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AL-FARABI KAZAKH NATIONAL UNIVERSITY
TEST TASKS ON CHEMICAL TECHNOLOGY Educational manual
Almaty «Qazaq University» 2020
UDC 66. 0 (075) BBC 35.11я73 Т 38 Recommended for publication by the decision of the Academic Council of the Faculty of Chemistry and Chemical Technology and Editorial and Publishing Council of al-Farabi KazNU (Protocol No.3 dated 13.03.2020) Reviewer Doctor of Chemistry, Professor S.M. Tazhibayeva
Test tasks on chemical technology: educational manual / Y.A. Aubakirov, Zh.Kh. Tashmukhambetova, L.R. Sassykova, [et al.]. – Almaty: Qazaq University, 2020. – 284 p. ISBN 978-601-04-4588-8 The manual contains test tasks for the main sections of the course «General Chemical Technology» for the Specialty «5В072000 – Chemical Technology of Inorganic Substances». The educational manual is intended for the organization of independent work of students. The educational manual contains a very detailed glossary, questions for self-control to each chapter. It can be useful for bachelors, masters of chemical and technological specialties of higher educational institutions and for engineering and technical workers in the chemical and allied industries.
UDC 66. 0 (075) BBC 35.11я73 ISBN 978-601-04-4588-8
© Aubakirov Y.A., Tashmukhambetova Zh.Kh., Sassykova L.R., [et al.]., 2020 © Al-Farabi KazNU, 2020
PREFACE The basic discipline «General Chemical Technology» is aimed at generalizing and consolidating the fundamental theoretical knowledge in the most important areas of chemistry, deepening this knowledge with examples of practical implementation in the form of existing and promising chemical technologies. This is intended to contribute to the completion of university training in the chosen direction of chemical education. In accordance with the current main program of the specialty, the discipline includes the study of the theoretical foundations of chemical technology and their practical implementation by the example of learning the most important industrial technologies of inorganic production. Training of specialists in the field of chemical technology of inorganic substances and materials has its own specifics. First, the problem of studying the theoretical foundations of chemical technology is solved: the physicochemical laws of chemical technological processes, the fundamentals of economics, the organization and planning of the chemical industry, etc. Secondly, an attempt is being made to integrate theoretical concepts of the natural science and fundamental chemical disciplines with the practical aspects of implementation of modern industrial technologies of inorganic production based on the relevant requirements for raw materials, energy resources and the economy of processes. The purpose of the course «General Chemical Technology» is to provide students of the specialty «5В072000 – Chemical Technology of Inorganic Substances» of chemical faculties of universities with knowledge on general techniques of using the laws of chemical, physical and technological sciences to solve the final problems of technology applied to mass industrial production of inorganic substances and organization of modern industrial production and its economy. In this regard, the course of chemical technology of inorganic substances should: – provide basic information on the current development trends and the relationship of chemical production processes, integrated use of raw materials and energy, creation of non-waste production and use of the most important types of chemical products; 3
– provide basic information on the main methods of transition from experimental study of the process to industrial production, methods of physical and mathematical modeling of chemical-technological processes, as well as their optimization; – provide basic information on the main issues of labor protection and environmental protection from harmful wastes of chemical plants (when considering each specific technological process); – provide basic information on the main technological problems of chemical and related industries, including the Republic of Kazakhstan in terms of future economic development. The main task of the «Test tasks on chemical technology» is to form practical skills and competencies of students. Along with knowledge of the basics of the theory of chemical technological production, the principles of rational use of raw materials, fuel and energy resources, environmental protection, students should fully master the development and implementation of technological processes, design, construction and operation of chemical equipment and many other practical problems of chemical technology. The following questions must be included in the mandatory minimum content of tests in the educational program of the university course «General Chemical Technology» for specialty 5В072000 – Chemical Technology of Inorganic Substances: – chemical production: hierarchical organization of processes in chemical production; criteria for evaluating production efficiency; general laws of chemical processes; industrial catalysis; – chemical reactors: basic mathematical models of processes in chemical reactors; isothermal and non-isothermal processes in chemical reactors; industrial chemical reactors; – chemical process systems (CPS): structure and description of CPS; CPS synthesis and analysis; raw materials and energy subsystems CPS; – energy in chemical production: the most important industrial chemical production. This manual contains test tasks according to the main sections of the course «General Chemical Technology» and is intended for the organization of independent work of students and its educational and methodological support. 4
1. INTRODUCTION TO GENERAL CHEMICAL TECHNOLOGY
1.1. General questions of chemical technology The essence of the subject «General Chemical Technology». The history of the development of Chemical Technology. Chemical Industry of the Republic of Kazakhstan. The most important technological concepts and definitions. Classification of technological processes on the basis of phase Modern chemical production is based on the achievements of science and technology. The basis of chemical production is chemical technology. From the Greek language, the term «technology» is translated as the science of the ability to do or create (technos – art, craft; logos – science, teaching). The object of chemical technology is substances and systems of substances involved in chemical production, or chemical production itself. The processes of chemical technology are a combination of various operations carried out in the course of production in order to transform one substance into another. General chemical technology is a science studying the most economic chemical ways of processing of raw materials into target products and means of production. General Chemical Technology is divided into Mechanical Technology, which studies the processes associated with changes in size, shape, state of aggregation, the crystalline structure of substances, and Chemical Technology. Chemical technology considers not only methods of chemical processing, but also a variety of physical, chemical and mechanical processes. Chemical technology studies the processsing reactions that are associated with changes in the composition, structure and properties of substances, that is, with their chemical transformation into other substances. 5
The subject of study of chemical technology is chemical production, as a method of processing initial materials (raw materials) into useful products. The purpose of the study of chemical technology is to create appropriate ways to produce the necessary human products. Chemical technology is divided by industry into two groups: inorganic and organic. History The basis of foundations of chemical technology was laid back in antiquity, mainly in ancient China, the states of the Ancient East, America, and later in Europe, Russia and other countries. But as an independent scientific direction, chemical technology was formed by the middle of the 20th century, although the prerequisites for this were the achievements of scientists beginning in the 8th century and the succeeding centuries. Modern chemical production begins with the invention of the French chemist Leblanc of the technology of soda production in 1789. This led scientists to the need to develop new technologies for the production of sulfuric and hydrochloric acids, mineral fertilizers, ammonia and nitric acid, later synthetic rubber, synthetic dyes, catalytic raw materials, etc., which became the basis for the further development of industrial production. In Russia, chemical technology was separated from theoretical chemistry and became an independent science in the 1800s, when the first Department of Chemical Technology was established at the Academy of Sciences, the first «Technological Journal» and textbooks were published, the St. Petersburg Practical Technology Institute was organized and for the first time general courses in chemical technology began to be read. Later in the works of eminent chemists D.I. Mendeleev, N.N. Zinin, N.D. Zelinsky, I.N. Kablukov, N.N. Vorozhtsov, A.G. Kasatkin, S.I. Wolfkovich, P.M. Lukyanov, P.T. Romankov and others scientific foundations of chemical technology were laid. Only by 1914 in Russia there were more than 70 chemical plants. The organization of a number of scientific institutions of the corresponding chemical technology profile, the development of basic research on chemical technology, the publication of textbooks and a chemical technology journal played a significant role in the development of the science of chemical technology. 6
In Kazakhstan, chemical production as a technology, unlike Russia, was developed much later – only at the end of the 19th century (1885 – industrial production of wormwood for the production of the drug santonin). The development of the chemical industry in Kazakhstan was closely and directly connected with the study of natural resources. During this period the main attention was paid to the geological and geochemical research connected with specification of geological reserves and search for new mineral deposits. In 1928-1930 the Committee on Chemicalization of Kazakhstan was organized. Studying of raw material resources of the republic and training of chemists was its main direction. The most important practical problems were covered: study of mineral resources, development of advanced technology of enrichment and smelting of metals, production of refractories and building materials, etc. It is necessary to refer to works of geochemists, geologists-mineralogists V.I. Vernadsky and A.E. Fersman to number the most important in this area. In 1930 the Aktyubinsk chemical plant for the production of mineral fertilizers was built. In 1932, construction began on the Aralsulfat processing plant in the Kyzylorda region based on proven reserves of mirabilite and tenardite, from which anhydrous sodium sulfate was obtained for glass plants, production of sodium chloride, magnesium chloride, etc. In 1935, the domestic production of boron compounds from potassium-boron ore deposits Inder (work of academician A.B. Bekturov) was organized. In the post-war period (1945) the Kazakh metallurgical plant was built, the capacity of Aktobe ferroalloys plant increased, the first stage of Karatau mining and chemical plant was put into operation. Since 1958, the construction of new facilities of the chemical industry has been widely developed. The main direction was the production of mineral fertilizers. The development of Karatau phosphorites resolved the issue of supplying phosphate fertilizers throughout Central Asia. Phosphorite processing has allowed Kazakhstan to create powerful enterprises for obtaining elemental yellow phosphorus using an electrothermal process. It was decided to construct the Dzhambul double superphosphate plant. The production of sodium silicofluoride was mastered. 7
A workshop for the production of ammophos was put into operation. The technology of extraction of phosphoric acid by anhydride method was developed. In Chimkent hydrolysis and tire repair plants began to operate. In the 1960s due to the pronounced raw material orientation of the economy of the republic, extractive industries received priority development. In 1961-1965 years, 729 large industrial enterprises and 535 workshops were put into operation. In the second half of the 1960s, 445 large enterprises and workshops were put into operation, hundreds of factories and plants were reconstructed and technically re-equipped. The ferrous and non-ferrous metallurgy, oil and gas, chemical and petrochemical industries were accelerated, a number of new industries for the production of titanium, magnesium, alumina, cast iron, coke, synthetic rubber, cranes, electric motors, new drawing mills and forging machines, asbestos, etc. appeared. During these years, construction of the Aktyubinsk chemical plant in the city of Alga, for the production of precipitate, started. For processing of phosphate ores, a special technological enrichment scheme was developed to obtain standardized flotation concentrate. In 1963, the second phase of the Aktyubinsk plant of chromium compounds, the Karaganda synthetic rubber plant, and the Guryev chemical plant were commissioned. Tire-repair plants were built in Tselinograd, Kustanai, Karaganda, and Pavlodar. Sulfuric acid workshops were launched at the Balkhash Mining and Metallurgical Combine and at the Chimkent Lead Plant. At the Karaganda Metallurgical Plant, coke-chemical production was developed. In 1964, for processing of Karatau ores, the gravity enrichment method was used in heavy suspensions to produce final products in the form of concentrate and waste, as well as intermediate products – objects for flotation or roasting. The process is based on the technology developed by scientists L.I. Stremovsky and M.I. Baskakova. For the first time, the flotation separation of phosphates from magnesium carbonates was carried out by sequentially separating of first carbonates into the foam in an acidic medium, and then phosphate from the chamber product in an alkaline medium. The process of enrichment of Karatau carbonate ores using roasting was also developed. 8
In 1965, there were five plants in Karaganda, Aktyubinsk, Semipalatinsk, Ust-Kamenogorsk and Chimkent. The Karaganda and Semipalatinsk plants for asbestos-cement products and the Chimkent plant for asbestos-cement constructions were commissioned. In the 1970s capacities for production of mineral fertilizers at the Dzhambul superphosphate plant, where new workshops on production of sulfonated coal and defluorinated fodder phosphates were commissioned, considerably increased. Production by the method of melting of natural phosphates and defluorinatings in the cyclonic furnace was first developed. The company began to produce ammoniated superphosphate – a fertilizer with better physical and agrochemical properties than simple superphosphate. During these years, Kazakhstan produced in the country most of the yellow phosphorus, 40% of chromite salts, 20% of low-pressure polyethylene, over 10% of sulfuric acid. The power industry was successfully developing in the republic. The coal industry has gained significant development. In the Karaganda and Ekibastuz basins, coal production reached 61 million tons per year, of which 41% was mined in the most progressive, open, way. One of the leading industries was the steel industry. At the Sokolov-Sarbai mining and processing plant, ore enrichment and industrial production of high-quality iron ore pellets were established. The Karaganda Iron and Steel Combine became the largest enterprise with a full metallurgical cycle on production of special profiles of a hire, high-quality steel and cast iron. The first stage of the Ermakovsky plant of ferroalloys with production of ferrosilicium was commissioned. All this led to a significant increase in the share of Kazakhstan in the all-Union production of ferrous metals. The republic ranked first in the country in the extraction of chromite ores, the third in the production of iron and manganese ores; the role of the republic in the production of steel, rolled products, and ferroalloys increased. Non-ferrous metallurgy was further developed. Tishinsky mine and zinc plant at Leninogorsk polymetallic plant, the largest in the country mines of Dzhezkazgan mining and metallurgical complex were put into operation; the complex of alumina production of Pavlodar aluminum plant, Ust-Kamenogorsk titanium-magnesium plant reached initial design capacities. The production capacities of the Ust-Kamenogorsk Lead-Zinc and Balkhash Mining and Metallurgical Complex were expanded. The oil industry also developed at an acelerated pace. 9
All this created the necessary basis for the development of chemical technology in Kazakhstan and necessitated training of required engineering and technical personnel. Schemes of the movement of material and power flows. Periodic, semi-continuous and continuous processes. Essence and methods of drawing up and presentation of material and power balances. Definition of product yield and coefficient of useful energy application. Determination of power, productivity and intensity of production. The economic requirements imposed to rational production The economic efficiency of chemical production is one of its most important criteria. It depends on the scientific and technical level and production capacity. The level of chemical production is determined by a set of technical and economic indicators (TEI): the yield of the target product, the degree of conversion of raw materials, productivity, intensity of the apparatus, expenditure ratios for raw materials and energy, process selectivity, product quality, labor productivity, cost of production. They depend on a number of factors that characterize the state of production: the age of the enterprise, the technical condition of the equipment, the degree of automation of production, the qualifications of personnel, the level of work organization, the progressiveness of the technologies used, etc. Technical and economic indicators characterize the possibility of production of products of a given nomenclature and quality and are the criteria for assessing its economic feasibility and profitability. They are used to assess the status, plan and update production. The yield of the target product (η) is the ratio of the mass (quantity) of the obtained product to the mass of raw materials spent on its production. For a one-step process, A → B, the yield is: ηB = mB/mA.
For a multistage process, the total yield (ηΣ) is equal to the product of the yields of each stage of the equation A → B → D: ηΣ = ηА·ηВ…ηn. For irreversible reactions (A → B), the yield is defined as the ratio of the mass of the product obtained in practice mВ(p) to the theoretically possible mass according to the stoichiometric equation mВ(t): η = mВ(p)/mВ(t). For a reversible reaction (A ⇄ B), the yield is defined as the ratio of the mass of a product obtained in practice, mВ(p), to its theoretically maximum possible mass mВmax(t) under given conditions: η = mВ(p)/mВmax(t). The degree of conversion or conversion (X) is the ratio of the mass of the raw material that entered into chemical conversion during the time τ to its initial mass: XА = (mАo – mАτ)/mАo. where: mАτ is the amount of raw material that has not entered into the reaction by the time τ; mАo is the initial mass of the raw material; (mАo – mАτ) is the amount of raw material that entered into chemical transformation during the time τ. The product yield and the degree of conversion of raw materials are expressed in mass fractions or percent. Productivity (P) is the amount of the target product produced per unit of time, or the amount of raw materials processed per unit of time τ: P = т/τ, where т is the amount of product produced in time τ.
Productivity can be attributed both to a separate unit, and to the process line, workshop and enterprise as a whole. Power (M) is the highest possible productivity (performance). Productivity and power are expressed in kg/h, t/h, nm3/day, t/year, etc., depending on the scale of production. The intensity (I) is a criterion of overall performance of the device. It allows us to compare devices of various power by efficiency and is expressed in kg/m3 or kg/m2. The intensity of the device (the car, the reactor) is the ratio of its productivity to the unit of the size characterizing the sizes of the working part of the device – the volume of reactor V or the area of its section S: I = P/V or P/S, where P is productivity. Expense ratio (β) is the amount of raw materials, water or energy (Q) spent on production of a unit of mass or volume of the target product (m). For raw materials, β is expressed in t/t, nm3/t, nm3/nm3; for energy, respectively, in kW·h/t, kW·h/nm3. β = Q/m. Selectivity (σ) is the ratio of the mass of the target product to the total mass of the products obtained in the reaction. Selectivity characterizes the predominance of one of the directions of the process, if the transformation of raw materials leads to the formation of several final products. So, if the process proceeds according to a parallel scheme:
where: B is the target product, D is a by-product, then the selectivity for products B and D will be respectively equal to: σВ = mB/(mB + mD). 12
Since mB + mD = mАo – mА, then: σВ = mВ/(mАo – mА). The yield of the product, the degree of conversion of raw materials and selectivity are technical and economic indicators characterizing the depth of the chemical process. They are interconnected by the following system of equations, which were derived by appropriate substitutions: a) for an irreversible process А В: ηВ = ХA, b) for a simple reversible process А ⇄ В: ηВ = XA/ХA*, where XA* is the equilibrium degree of conversion of the initial reagent A, c) for a parallel reaction, the relationship between ηВ, ХA and σВ is determined by the equation: ηВ = ХA· σВ. Product quality is a combination of technical, operational, economic and other properties that determine its suitability for consumption. Product quality is measured in accordance with State Standards (SS) and technical specifications (TS) on products. The cost efficiency of production is caused by such indicators as capital expenditure, product cost and labor productivity. They are closely connected among themselves and depend on the structure of economy of chemical production, in particular, on specific weight in it of fixed and circulating assets and the wages fund. Financial resources intended for simple and expanded reproduction of fixed assets are characterized by capital expenditures. Capital expenditures are the sum of all costs incurred in the construction of a workshop or an enterprise as a whole. 13
They include the cost of purchasing equipment, machinery and equipment (the active part) and construction and installation work (the passive part). The efficiency of return on capital expenditures depends on the share of their active part and is estimated by the criterion «specific capital expenditures», that is, the cost per unit of output: P = Ce/M where: Ce are capital expenditures in tenge, M is an annual capacity of the installation (workshop, enterprise) t/year, therefore, specific capital expenditures are expressed in tenge/t/year. With the growth of the annual capacity of technological units and installations, the specific capital costs are reduced in accordance with the formula: P = a · M -0.4, where: a is a coefficient depending on the type of production. For example, if the annual capacity of an installation of the same production doubles (M2 =2M1), then the ratio of specific capital costs will be equal to: P1/P2 = (а ·M1-0.4/а ·M2 -0.4) = 0.5-0.4= 0.76. This means that specific capital costs will decrease by 24%. The economic indicator of profitability of production is the cost of production. The cost of production (S) is the sum of all the costs of the enterprise in monetary terms related to the manufacture and sale of a unit of mass (volume) of its products. The expenses of the enterprise which are directly connected with production represent factory prime cost and include costs of means of production, compensation and services of other enterprises, on management and service of production. High costs of raw materials about 70 – 80% of the total costs are characteristic of chemical industry. 14
Similar to capital costs, the cost of production decreases with an increase in the unit capacity of the aggregates in accordance with the dependence: S = а .M b where: S is the cost of production, tenge/t, M is the capacity of the unit (workshop, enterprise), t/year; a, b are coefficients, with b = -0.2 (to -0.3). S1/S2 = M1-0.2/M2-0.2= 0.5-0.2 = 0.87 From the equation it follows that with doubling of the capacity of the unit at b = -0.2, the prime cost of the products will be 0.87, that is, decrease by 13%. Labor productivity is the amount of the target product produced by the worker per unit of time. It depends on the achievements of scientific and technological progress, improvement of the organization of production, professional level of staff. For measurement of labor productivity the criterion of standard labor input as which labor input of industrial and production personnel on production of a unit of production is used. At the same time we distinguish: – technological labor input, that is labor input of the main production workers; – shop labor input, that is labor input of all personnel of the shop; – manufacturing labor input, that is labor input of all industrial and production personnel of the enterprise in general. Schemes of movement of material and power flows. Periodic, semi-continuous and continuous processes. Essence and methods of drawing up and presentation of material and power balances. The processes of chemical technology by the organizational and technical structure are divided into periodic (batch) and continuous. In batch processes, all stages: loading of raw materials, carrying out of the process, and unloading of the product, are carried out in the same apparatus, but at different times. 15
In continuous processes, all stages: loading of raw materials, carrying out the process and unloading of the product are carried out simultaneously, but in different devices or different sections of the same device. A characteristic that allows the process to be attributed to a particular group is Xcontinuous – the degree of continuity of the process: Хcontinuous = t/Δt, where: t is the duration of the process, that is, the time required for completion of all stages, Δt is the process period, that is, the time from the start of loading of raw materials of one batch to the beginning of loading of raw materials of the next batch. For a periodic process, Δt > 0, therefore, Xcontinuous < 1, for a continuous process, Δt → 0, therefore, Хcontinuous → ∞. The intermediate place between these extreme cases is occupied by semi-continuous processes, for which Хcontinuous = 1 ± ∞. Any chemical production can be considered as a combination of the movement of material flows, presented by the components of the raw materials, intermediate and by-products, the end product, production waste. During the process, there is a continuous movement and change in the nature of the substances taking part in it. The movement and transformation of all material participants in the technological process are depicted in the form of material-flow graphs. A material flow is a graphic display of the movement and change of substances involved in the chemical process. The material flow is expressed in the form of a material-flow graph (MFG) of the process, that is, a graphic scheme that reflects the nature of the substance, the direction of its movement, the change in the state of aggregation and chemical composition. In MFG, there are «knots», that is, devices and machines, and «edges» – substances moving in the process. Material flows can be of three types: – divergent, in which the number of products increases as a result of the process (for example, electrolysis of an aqueous solution of sodium chloride), 16
– converging, in which the number of products as a result of the process is reduced (for example, ammonia synthesis), – intersecting, in which the number of products as a result of the process does not change explicitly (for example, roasting of pyrites). Based on the analysis of MFG (the material flow graph), the material balance of the process is compiled. Material balance is an expression of the law of conservation of mass: the mass of substances (m) received for a technological operation (input) is equal to the mass of substances obtained in this operation (consumption), and is written in the form of a balance equation: Σminput = Σmconsumption Items of input and consumption in the material balance are the mass of the useful component of the raw material (m1), impurities or moisture in the raw material (m2), the target product (m3), by-products (m4), production waste (m5) and losses (m6) obtained in production or operation: m1 + m2 = m3 + m4 + m5 + т6 The material balance is compiled per unit mass of the target product or per unit (reactor) and is expressed in mass units (kg, t) or mass fractions (μ). For periodic processes, the material balance is compiled for one operation, for continuous processes – per unit of time. On the basis of the material balance, expenditure coefficients are calculated, the size of the apparatus is determined and the optimal values of the parameters of the technological mode of the process are established. The energy balance is based on the law of energy conservation, according to which in a closed system the sum of energies of all types is constant. A special and the most common type of energy balance in chemical production is heat balance: the heat input in this technological operation is equal to the heat consumption in it, which is written in the form of the heat balance equation: 17
ΣQinput = ΣQconsumption The elements of input and consumption in the heat balance are the thermal effects of ∆H reactions, the heat of phase transitions (Q1), the heat content of substances involved in the process (Q2), the heat supplied to the apparatus from the outside and output from the apparatus (Q3), the heat loss (Q4) in this operation: ∆H + Q1 + Q2 + Q3= ∆H' + Q1' + Q2' + Q3' + Q4', where: index (‘) refers to expense items. Thermal contributions to the balance are determined by the known formulas, and the thermal effect of a chemical reaction is calculated in accordance with the equation: ∆H = Σ ∆Hproduct – Σ ∆Hstarting materials, in which the enthalpy values of the reaction products (product) and the starting materials (starting materials) are tabular data. The heat content of substances is calculated by the formula: Q2 = т.с.t, where: m is the mass of a substance, c is its heat capacity, t is the temperature. The heat of phase transitions is calculated by the formula: Q1 = m.q, where: q is the specific heat of the corresponding phase transition (evaporation, condensation, dissolution, crystallization), t is the mass of the substance. Supply and removal of heat from the system are calculated by the heat loss by the coolant according to the formula: Q3 = m.с(ti – tf) where: t is the mass of the coolant, c is the heat capacity of the coolant, ti and tf are the initial and final temperature of the heat carrier, and according to the formula of heat transfer through the wall: 18
Q3 = CT · F (tτ – thр), where: CT is the heat transfer coefficient, F is the heat exchange surface, thc is the heat carrier temperature, thp is the temperature of the heated product, τ is the time. The heat balance is compiled based on the results of the material balance per unit of product produced or on the cycle of operation of the apparatus. The heat balance data is used to determine the flow rate of the coolant and refrigerant, calculate the surface of the heating and cooling elements, and select the optimal thermal mode of the process. TEST TASKS 1. Science about the most economic chemical ways of processing of raw materials in target products and means of production: A) organic chemistry; B) chemical technology; C) physical chemistry; D) technology; E) inorganic chemistry. 2. General chemical technology studies the processes: A) mass transfer; B) chemical; C) hydromechanical; D) thermal; E) energy exchange. 3. Graphic representation of a set of links between individual nodes of a chemical process: A) a technology map; B) a sequence of devices; C) a schematic diagram; D) a symbol of the apparatus; E) a chemical process system. 4. The combination of various technological processes (chemical, thermal, diffusion), occurring in one apparatus, is called: A) mixing; B) chemical transformation; C) operation; D) a set of processes; E) interaction.
5. Production of products based on processes occurring in a living cell refers to: A) technology of basic organic synthesis; B) high molecular technology; C) biotechnology; D) production of organic products; E) molecular chemistry. 6. Production of drugs and medicinal substances refers to: A) fine organic synthesis; B) biotechnology; C) basic organic synthesis; D) petrochemical synthesis; E) biochemical synthesis. 7. Preparation and processing of raw materials, preparation of auxiliary materials, product separation, waste disposal, water treatment, production management are: A) production; B) constituent parts of the proceedings; C) production components; D) production stages; E) auxiliary production. 8. Raw materials, auxiliary materials, products, waste, energy are: A) variable production components; B) permanent production components; C) production components; D) source materials; E) basic components. 9. Building structures, equipment, control and management devices, and maintenance personnel refer to: A) variable production components; B) the main components of production; C) permanent production components; D) original production components; E) basic production components. 10. Substances and materials to be further processed or sent for recycling are called: A) by-products; B) semi-products; C) supporting materials; D) secondary raw materials; E) conditioned products.
11. The chemicals entering for processing are called: A) expendables; B) raw materials; C) initial materials; D) reagents; E) catalysts. 12. The main chemicals obtained from the processing of raw materials and intended for consumption are called: A) products; B) semi-products; C) synthesized substances; D) target products; E) commodity products. 13. The selection of process parameters (temperature, pressure, concentration, catalyst, etc.) to increase the composition and yield of the target product is called: A) optimization; B) selection of the technological mode; C) preparation of the flow chart (technological map); D) drawing up a technological scheme; E) selection of technological operators. 14. The set of parameters that determine the operating conditions of the apparatus or system of apparatuses: A) technological mode; B) flow chart (technological map); C) technological scheme; D) optimal conditions; E) technological operators. 15. The mass transfer processes of the chemical process are: A) cooling; B) crystallization; C) crushing; D) filtering; E) sublimation. 16. The mechanical chemical process is: A) crushing; B) extraction; C) dissolving; D) filtering; E) evaporation.
17. The aggregate state of the reactants and reaction products characterizes: A) the ratio of components; B) volume; C) phase composition; D) concentration; E) dispersion. 18. If the starting materials and products are in the same phase, then the process is: A) homogeneous; B) heterogeneous; C) gas dynamic; D) mass transfer; E) equilibrium. 19. If the starting materials and products are in different phases, then the process is: A) homogeneous; B) gas dynamic; C) heterogeneous; D) hydrodynamic; E) catalytic. 20. If the reactor maintains a constant temperature throughout the reaction volume, then the process is: A) adiabatic; B) isothermal; C) polythermal; D) endothermic; E) exothermic. 21. A reactor in which there is no heat supply or removal and all energy is accumulated by the flow of reactants is: A) software adjustable; B) adiabatic; C) isothermal; D) polythermal; E) isochoric. 22. A reactor in which heat is only partially removed from the reaction zone or is compensated by the supply for endothermic processes is: A) isothermal; B) adiabatic; C) polythermal; D) exothermic; E) endothermic.
23. Exothermic reactions are accompanied by: A) a release of heat and a decrease in the enthalpy of the reaction system; B) absorption of heat and an increase in the enthalpy of the reaction system; C) a release of heat and an increase in the enthalpy of the reaction system; D) absorption of heat and a decrease in the enthalpy of the reaction system; E) heat release. 24. Endothermic reactions are accompanied by: A) a release of heat and a decrease in the enthalpy of the reaction system; B) absorption of heat and an increase in the enthalpy of the reaction system; C) a release of heat and an increase in the enthalpy of the reaction system; D) absorption of heat and a decrease in the enthalpy of the reaction system; E) heat absorption. 25. The amount of raw materials or energy spent on the production of a unit of product is called A) product yield; B) process power; C) expense ratio; D) intensity; E) performance (productivity). 26. The ratio of the amount of product obtained from raw materials to its maximum theoretically possible amount is: A) expense ratio; B) process intensity; C) product yield; D) power; E) performance (productivity). 27. The number of processed raw materials or the resulting product per unit of time describes: A) process power; B) the speed of the process; C) performance (productivity); D) reaction rate; E) the yield of the target product. 28. The share of feedstock, turned into a product, describes: A) degree of conversion; B) selectivity; C) product yield; D) performance (productivity); E) power. 29. The product value and consumer properties of the product are determined by: A) product quality;
B) the appearance of the product; C) the content of impurities in the product; D) water content; E) dispersion. 30. The average time of trouble-free operation, or the number of emergency stops of equipment or production for a certain period of time characterizes: A) quality of equipment; B) operating conditions; C) the correct service; D) reliability; E) effectiveness. 31. In a reactor with a volume of 2 m3 in 30 seconds, 80 kg of the starting material was converted. Determine the rate of transformation of the original substance: A) 2.67; B) 2.27; C) 2.01; D) 2.10; E) 3.00. 32. In a 3 m3 reactor in 60 seconds, 25 kg of the starting material was converted. Determine the rate of transformation of the original substance: A) 0.35; B) 0.39; C) 0.40; D) 0.46; E) 0.42. 33. The concentration of the initial substance at the entrance to the reactor is 10 mol/L, and at the exit of the reactor 0.07 mol/L. Determine the degree of conversion of the initial substance: A) 0.96; B) 0.79; C) 0.95; D) 0.84; E) 0.99. 34. The concentration of the initial substance at the reactor inlet is 13.8 mol/L, and at the reactor exit 0.6 mol/L. Determine the degree of conversion of the initial substance: A) 0.96; B) 0.93; C) 0.99; D) 0.79; E) 0.58.
35. The concentration of the initial substance A at the reactor inlet is 10 mol/L. The concentration of the product at the outlet of the reactor is 4 mol/L. The process is characterized by a stoichiometric equation: 2A = B. Determine the yield of product B: A) 0.80; B) 0.95; C) 0.68; D) 0.75; E) 0.67. 36. The concentration of the initial substance A at the reactor inlet is 15 mol/L. The concentration of the product B at the outlet of the reactor is 9.5 mol/L. The process is characterized by a stoichiometric equation: 2A = B. Determine the yield of product B: A) 1.27; B) 0.94; C) 1.33; D) 0.99; E) 1.17. 37. The concentration of raw material A at the reactor inlet was 12.45 mol/L. At the outlet of the reactor, the concentration of the initial substance A was 4 mol/L, and the target product B – 6 mol/L. Determine the selectivity of the process for the target product B, if the process is described by the equations: 2А → В; А → С. A) 1.45; B) 0.98; C) 1.53; D) 1.41; E) 1.46. 38. The concentration of raw material A at the reactor inlet was 15.0 mol/L. At the outlet of the reactor, the concentration of the initial substance A was 1 mol/L, and the target product B – 7 mol/L. Determine the selectivity of the process for the target product B, if the process is described by the equations: 2А → В; А → С. A) 1.08; B) 0.99; C) 0.97; D) 1.00; E) 1.12. 39. Substances and materials intended for processing in industrial production are called: A) raw materials; B) intermediate product; C) by-product; D) waste; E) reagents.
40. Substances formed during the processing of raw materials along with the target product, which are not the target product of this production, are called: A) intermediate; B) raw materials; C) by-product; D) waste; E) slags. 41. Residues of raw materials, materials, the semi-products which are formed in production and fully or partially lost their qualities, are called: A) production wastes; B) garbage; C) semi-product; D) by-product; E) pitch. 42. The cost of raw materials in the chemical industry as a part of the cost of production: A) less than 30%; B) up to 70-80%; C) 45-55%; D) 15-20%; E) up to 60 %. 43. Ways of intensifying a heterogeneous process occurring in the external diffusion region: A) pressure increase; B) an increase in the linear velocity of the gas stream, an increase in temperature; C) temperature increase; D) grinding the solid reagent; E) intensive mixing. 44. Ways to intensify a heterogeneous process occurring in the intra-diffusion region: A) grinding a solid product; B) an increase in the linear velocity of the gas stream, intensive mixing; C) an increase in temperature; D) increasing the temperature and concentration of the reagent; E) an increase in the linear velocity of the gas stream, an increase in the concentration of the reagent. 45. Ways to intensify a heterogeneous process occurring in the kinetic region: A) grinding a solid product; B) increasing the concentration of the reagent; C) an increase in the linear velocity of the gas stream; D) reducing the linear velocity of the gas stream; E) a decrease in temperature.
46. A method of increasing the contact surface of phases in a gas-solid system: A) supply of reagents to the reaction zone; B) increase in temperature and pressure; C) increasing the concentration of reagents; D) removal of products from the reaction zone; E) passing the gas stream through a fixed bed of granules of solid material. 47. A method for increasing the driving force of a heterogeneous process: A) grinding solids; B) removal of products from the reaction zone; C) intensive mixing; D) temperature increase; E) increase in selectivity. 48. The processes of chemical technology by the organizational and technical structure are divided into: A) cyclic and non-cyclic; B) periodic and continuous; C) discontinuous and continuous; D) stationary and non-stationary; E) rotational and translational. 49. The material balance of the chemical-technological system (CTS) is determined by the ratio of minput and mconsumption: A) Σ mconsumption.= Σ minput; B) Σmconsumption= 1/2Σ minput; C) Σ minput =1/2 Σmconsumption; D) Σ minput = Σmconsumption /Σmtheoretical consumption; E) Σminput = Σmconsumption 50. The heat or energy balance of the chemical-technological system (CTS) is determined by the ratio Qinput and Qconsumption: A) ΣQconsumption = ΣQ input; B) ΣQconsumption = 1/2ΣQinput; C) ΣQinput =1/2 ΣQconsumption; D) ΣQinput = ΣQconsumption./ ΣQ theoretical consumption; E) ΣQinput = ΣQconsumption
1.2. Basic laws and methods of chemical technology The importance of thermodynamic and kinetic (micro- and macro) laws in chemical technology. Factors determining the rate of homogeneous and heterogeneous reactions. The influence of the concentration of reagents, temperature, pressure, renewal of the contact surface of the reacting phases and other physical and chemical factors on the course of chemical-technological processes, methods of their regulation 27
Unlike theoretical chemistry, chemical technology takes into account the economic requirements for the production it studies. Chemical technology as a science cannot be reduced to purely theoretical chemistry, but at the same time it is based on the concepts, laws, and conclusions of theoretical chemistry. The goal of chemical technology is a comprehensive study of common chemical, physical and technological phenomena in such a multifactor system as an industrial chemical process. Chemical technology uses such parameters as temperature, heat effect, pressure, concentration of reactants, velocity, phase surface, volume of the reaction phase, the degree of conversion of raw materials into the target product, the yield of the product, the effect of the catalyst. A chemical approach is applied to chemical production processes and they introduce the concept of «the level of the process flow». This approach includes several subsystems or levels of increasing complexity, which are characterized by their method of study. The levels of chemical production are divided into: – molecular level, where the mechanism and kinetics of chemical transformations are described as molecular interaction («micro-kinetics»); – the level of small volume, where the phenomena are descrybed as the interaction of macroparticles (granules, drops, bubbles, catalyst grains, etc.) – «macrokinetics». «Macrokinetics» studies the effect of mass transfer of starting materials and reaction products, heat transfer and catalyst state on the rate of chemical transformations; – flow level, where phenomena are considered as the interaction of a set of particles, taking into account the nature of their movement in the flow (laminar, turbulent) and changes in temperature and concentration of reagents along the flow; – the level of the reactor, where the phenomena are described taking into account the design of the apparatus or reactor in which the technological process is implemented; – the level of the system, where for the consideration of phenolmena the interrelations between the technological units of the industrial installation and production as a whole are taken into account. Thus, the problem of distinction between theoretical chemistry and chemical technology is essentially the problem of differrence between basic scientific research and real industrial production. 28
Physical and chemical bases of chemical processes. Stoichiometry, thermodynamics, kinetics of chemical reactions. Classification of chemical processes. Homogeneous, heterogeneous chemical processes. The essence and importance of optimization and physico-chemical conditions of chemical and technological processes. Mathematical modeling of chemical-technological processes The stoichiometric equation shows the ratios of substances that enter into chemical interaction. General form of the stoichiometric equation is: νАА + νBВ + ... = νrR + νsS + ..., where A, B, ... are the starting materials; R, S, ... are products; νA, νB,νR, νS,... are the stoichiometric coefficients. The stoichiometric equation establishes the ratio between the amounts of converted substances: (NА0 – NА) / νA = (NВ0 – NВ) / νВ = (NR – NR0) / νR = (NS – NS0) / νs, where NА0, NВ0, NR0, NS0 is the initial amount of components А, В, R, S; and NА, NВ, NR, NS is the amount of the same components after transformation; (NА0 – NА), (NВ0 – NВ) is the amount of the converted initial substances A and B; (NR – NR0), (NS – NS0) is the amount of R and S products formed. A simple reaction is described by one stoichiometric equation, a complex reaction is described by several equations. An example of a simple reaction is the oxidation of sulfur dioxide: SO2 + 0.5O2 = SО3, An example of a complex reaction is methanol oxidation: 2СН3ОН +О2 = 2СН2О +2Н2О; 2СН3ОН +3О2 = 2СО2 +4Н2О. Processes of chemical technology, depending on the kinetic regularities characterizing their course are divided into five groups: 29
– hydromechanical processes, the rate of which is determined only by the laws of hydraulics; – thermal processes, the rate of which is determined by the laws of heat transfer; – mass transfer (diffusion) processes, the rate of which is determined by the laws of mass transfer; – mechanical processes; – chemical processes, the rate of which is determined by the laws of chemical kinetics (catalytic). Hydromechanical processes are: sedimentation, filtration, fluidization, mixing in the liquid phase. Thermal processes are: heating, cooling, condensation, evaporation, heat transfer. Mass transfer processes are: adsorption, absorption, rectifycation, extraction, drying. Extraction proceeds in extractors of different designs: mixing and settling; column; centrifugal and pulsation. Drying processes are: contact drying with heating the material through the wall; drying with heated gas or air; drying with high frequency currents; infrared radiation drying. Thermodynamics. The heat effect of the reaction A change in the chemical composition of the reacting mixture leads to a change in its heat content ΔHT, which can be calculated in terms of the enthalpy of formation of the components: ΔНТ = Σvi(ΔHТ)formation· i. If the enthalpy of formation of products is less than the enthalpy of formation of the starting materials, (ΔНТ < 0), then the heat Qp = -ΔHT, called the heat of reaction, is released. If during the chemical transformation the heat content of the mixture increases (ΔНТ > 0), then heat is absorbed. Depending on the sign of ΔН (or Qp), the reactions are exothermic (ΔH < 0, Qp > 0) and endothermic (ΔH > 0, Qp < 0). The heat effect of the reaction enters the thermochemical equation, which is a stoichiometric equation indicating its thermal result: 30
νАA + vBB + ... – νRR + νsS + ... + Qp The heat effect of the reaction is needed to determine the thermal phenomena in the process. The amount of heat released or absorbed qp depends on the amount of substance ΔN converted during the process: qp = Qp·ΔNА/νА. The sign Qp indicates whether during the course of the process heat is released or absorbed. A chemical process is possible if the reaction proceeds with a decrease in the chemical potential, called the isobaric potential or the Gibbs energy (G). The possibility of the reaction is determined by the following conditions: when ΔGT,P 0, the reaction is impossible; when ΔGT,P = 0, the system is in thermodynamic equilibrium. ΔGT,P is the change in the Gibbs energy during transformation of the initial substances into products at temperature T and pressure P. The change in the Gibbs energy in the reaction can be calculated by the equation: ΔGº298 = Σivi(Gº298)formation·i. The values of the standard Gibbs energy for the formation of substances at a standard temperature 298 K and pressure P = 1 atm (ΔGº298)formation·i are given in the reference literature on thermodynamics and mean the change in the Gibbs energy when converting such an amount of substance into the standard state, which is written in the stoichiometric equation. Example: there is an infinitely large amount of mixture containing H2, N2 and NH3 at a temperature T =298 K and a pressure РН2 = Р 2 = РН 3 = 1 . If 1 mole of N2 and 3 mole of H2 turn into this mixture (this will not affect the composition of an infinitely large amount of the mixture), then the change in the Gibbs energy will obey the given equation. 31
For the calculation in conditions different from the standard, use the dependence of the Gibbs energy on temperature: ΔGT,P =ΔНТ0 – ТΔS, where ΔНТ0, ТΔS, are the changes in enthalpy and entropy at standard pressure, which can be calculated using similar formulas. The dependence of the Gibbs energy on the composition of the reaction mixture reflects the Vant-Hoff equation: ΔGT,P = ΔGT0 + RTlnPiCivi, where R is the universal gas constant, equal to 8.314 j/mol·K; P is a product of numbers; Сi are concentrations of components; vi are the stoichiometric coefficients of the reaction equation in algebraic form: ΣiviAi = 0, where Ai are substances involved in the reaction (A, B, ..., R, S, ...); νi is the stoichiometric coefficient of the i-th substance. Equilibrium The yield of the target product of the chemical-technological process is determined by the degree of approximation of the reaction system to a state of stable equilibrium, which meets the following conditions: – invariance in time with the constancy of external conditions; – mobility or spontaneous rebalancing after the removal of external effects; – the dynamic nature of equilibrium due to the equalization of the rates of the direct and reverse processes; – the ability to influence the equilibrium from both the direct and reverse reactions; – the minimum value of the Gibbs energy in isobaric-isothermal processes and the Helmholtz energy in isochoric-isothermal processes. 32
The degree of approach of the system to the state of stable equilibrium is characterized by a change in the isobaric-isothermal potential and the equilibrium degree of transformation. The change in the isobarric-isothermal potential ΔG determines the thermodynamic probability of the reaction under these conditions and the depth of its course. The change in the isobaric-isothermal potential is equal to the difference between its values for the final reaction products and the initial reagents. So, for the reaction: аА + bВ → dD ± ΔН, ΔG = dΔGD) – (aΔGA + bΔGB). The sign and the order of magnitude ΔG allows us to estimate the equilibrium state of the system. Thus, at values ΔG < 0 the most probable is a direct reaction, and the greater is this inequality, the more likely is this direction of the process, at ΔG > 0 the most probable is the reverse reaction, the value ΔG = 0 corresponds to the equilibrium state of the system. According to the equation: ΔG = ΔН – TΔS, where: ΔH and ΔS are the standard enthalpy and entropy of a system, follows that the balance shift towards direct reaction is favorably influenced by high negative ΔH value (considerable thermal effect of reaction) and high positive ΔS value. Since entropy enters the equation in the form of a product TΔS, the increase in temperature increases the effect of the change in entropy. It is obvious that the equilibrium condition (ΔG = 0) is equality of ΔH = TΔS, that is, the influence of energy and entropy factors is equalized. At relatively low temperatures ΔG ≈ ΔN and a characteristic of the probability of the reaction can serve as its thermal effect and the more exothermic the reaction is, the more likely it is. To assess the equilibrium state in the reactor, an equilibrium degree of conversion is usually used (an equilibrium yield of the product). 33
The equilibrium degree of conversion (X*) is the degree of conversion of the starting materials into reaction products, corresponding to the state of stable equilibrium of the system. The equilibrium degree of conversion characterizes the depth of the process, the degree of approximation of its results to the optimum in given conditions. It is functionally related to the equilibrium constant (Kp), and the nature of this dependence is determined by the reaction order. For the 1st order reaction: Kp = Xp*/(1 – Xp*) or Xp*= Kp/(1 + Kp), for the reaction of the 2nd order: Kp = 4Xp*/(1 – Xp*)P. The relationship between the equilibrium constant and the equilibrium degree of conversion is one of the most important in chemical technology, since the latter characterizes the conditions for the maximum possible extraction of the target product from raw materials. The shift of equilibrium towards the formation of the target product can be achieved by changing the temperature, pressure and concentration of the reactants and reaction products. Influence of temperature From the equation of Van’t Hoff isobar it follows that K = f(T), and the equilibrium degree of transformation of X* depends on temperature: dlnK/dT = ΔН/RT2. The nature of this dependence is determined by the sign of the thermal effect of the reaction. For endothermic reactions, an increase in temperature shifts the equilibrium toward the formation of reaction products, that is, increases the equilibrium degree of conversion, and in the case of an exothermic reaction, vice versa, which is consistent with the Le Chatelier principle. 34
Influence of pressure Pressure has a significant effect on the state of equilibrium in gaseous systems. Three cases are possible: – the volume of the gaseous system decreases (ΔV < 0), for example, in the reaction: CO + 2H2 → CH3OH. In this case, an increase in pressure shifts the equilibrium towards the formation of reaction products; – the volume of the gaseous system increases (ΔV > 0), for example, in the reaction: СН4 → С + 2Н2. In this case, the equilibrium shift towards the formation of reaction products is achieved by lowering the pressure; – the volume of the gaseous system does not change, for example, in the reaction: CO + H2O → CO2 + H2. In this case, the change in pressure does not affect the equilibrium degree of conversion, but only the reaction rate. TEST TASKS 1. Specify the conditions under which the chemical process is fundamentally feasible at temperature T and pressure P, if ΔG298 =vi (G298)formation· i: A) ΔGT,P 0; C) for ΔGT,P = 1; D) 0 > GT,P < 1; E) for ΔGT,P < 0. 2. The reaction system is in thermodynamic equilibrium if the Gibbs energy change is: A) ΔGT,P < 0; B) ΔGT,P < 0; C) ΔGT,P = 0; D) 0 ΔGT,P < 1; E) ΔGT,P < 1.
3. The reaction equation: νAA + νBB + ... = νRR + νsS + ... + Qр, – represents: A) an equation of the exothermic reaction; B) an equation of the endothermic reaction; B) a stoichiometric reaction equation; D) a chemical reaction equation; D) a non-stoichiometric reaction equation. 4. The thermal effect of the chemical process qp depends on the amount of the converted substance ΔN. According to the thermochemical equation of a chemical reaction: vAA + vBB + ... = vRR + vsS + ... + Qр, the thermal effect corresponds to the formula: A) qp = NA/ Qp; B) qp = QpNA; C) qp = QpNRNA; D) qp = Qp(NA + NB+ … )/(vA+ vB + …); E) qp = QpNA/vA; 5. The aggregate state of the reacting substances and reaction products is characterized by: A) mass transfer in the reaction mixture; B) the phase composition of the reaction mixture; C) the ratio of the components in the reaction mixture; D) the volume of the reaction mixture; E) reaction stoichiometry. 6. Reaction: Ag+ + Cl- → AgCl↓ proceeds in one stage and is called: A) stoichiometric; B) one-molar; C) consecutive; D) single-stage; E) an elementary act. 7. The number of the molecules participating in the elementary act defines: A) reaction molecularity; B) reaction order; C) kinetic equation of the reaction; D) elementary act; E) staging of the reaction. 8. Determine the phase composition of the reaction: H2 (g) + I2 (g) = 2HI (g): A) heterogeneous reaction; B) gas phase reaction;
C) single phase reaction; D) heterophase reaction; E) homophasic reaction. 9. Determine the phase composition of the reaction: AgNO3 (solution) + NaCl (solution) = AgCl (solid phase) + NaNO3 (solution): A) liquid phase reaction; B) heterophase reaction; C) homogeneous reaction; D) liquid phase heterogeneous reaction; E) homophasic reaction. 10. Determine the phase composition of the reaction of formation of oxyhemoglobin in the cellular liquid of erythrocytes: Hb + O2 → HbO2: A) heterogeneous reaction; B) liquid-phase reaction; C) homogeneous reaction; D) liquid-phase homogeneous reaction; E) liquid-phase heterogeneous reaction. 11. In the kinetic equation: ν = k·[A]a·[B]b expressing the dependence of the reaction rate (v) on the concentration of reacting substances in the reaction: aА + bВ → cC + dD, – the sum of the indicators of the degrees of concentrations of the reacting substances (a+b) determines: A) reaction molecular weight; B) reaction rate; C) reaction order; D) molarity; E) direction. 12. Determine the reaction order: aA (gas) + bB (gas) + cC (gas) → dD (liquid) + eE (solid phase) A) a + b + c; B) (a + b + c)/2; C) 3/2 (a + b + c); D) a + b + c/d + e; E) (d + e)/2. 13. Determine the reaction order: aA (gas) + bB (gas) + cC (solid phase) → dD (liquid phase) + eE (solid phase) A) a + b + c; B) (a + b)/c; C) (d + e)/2; D) (a + b + c)/(d + e); E) (a + b + c)/2.
14. The amount of a substance that turns in a unit of time into a unit of reaction volume characterizes: A) rate of conversion; B) reaction rate; C) apparent speed constant; D) equilibrium constant; E) equilibrium concentration. 15. Complete the definition of the Le Chatelier principle: «if an equilibrium system is subjected to any influence from outside, the process taking place in the system ... and brings the system to a new equilibrium»: A) enhances this effect; B) attenuates this effect; C) is similar to this effect; D) eliminates this effect; E) opposes it. 16. In the system: 4NH3 (gas) + O2 (gas) ↔ 2N2 (gas) + 6H2O (gas), where ΔH < 0, the pressure increase will affect the equilibrium as follows: A) the balance does not change; B) the balance will shift to the right; C) the balance will shift to the left; D) the reaction becomes non-equilibrium; E) the reaction becomes equilibrium. 17. In the system: 4NH3 (gas) + O2 (gas) ↔ 2N2 (gas) + 6H20 (gas), where ΔH < 0, the temperature increase will affect the equilibrium in the following way: A) the reaction equilibrium does not change; B) the reaction equilibrium will shift to the right; C) the reaction equilibrium will shift to the left; D) the reaction will become non-equilibrium; E) the reaction will become equilibrium. 18. In the system: 2NO (gas) + O2 (gas) ↔ 2NO2 (gas), where ΔH < 0, the increase in pressure will affect the equilibrium in the following way: A) the reaction equilibrium does not change; B) the reaction equilibrium will shift to the right; C) the reaction equilibrium will shift to the left; D) the reaction will become non-equilibrium; E) the reaction will become equilibrium. 19. In the system: 2NO (gas) + O2 (gas) ↔ 2NO2 (gas), where ΔH > 0, the temperature increase will affect the equilibrium as follows: A) the reaction equilibrium does not change; B) the reaction equilibrium will shift to the right;
C) the reaction equilibrium will shift to the left; D) the reaction will become non-equilibrium; E) the reaction will become equilibrium. 20. In the system: H2O (liquid) ↔ H2O (gas), where ΔH > 0, the increase in pressure will affect the equilibrium as follows: A) the reaction equilibrium does not change; B) the reaction equilibrium will shift to the right; C) the reaction equilibrium will shift to the left; D) the reaction will become non-equilibrium; E) the reaction will become equilibrium. 21. In the system: H2O (liquid) ↔ H2O (gas), where ΔH > 0, – an increase in temperature will affect the equilibrium as follows: A) the reaction equilibrium does not change; B) the reaction equilibrium will shift to the right; C) the reaction equilibrium will shift to the left; D) the reaction will become non-equilibrium; E) the reaction will become equilibrium. 22. In an exothermic reaction with increasing temperature equilibrium is shifted to the side: A) formation of the starting materials; B) formation of reaction products; C) direct reaction; D) formation of intermediate products; E) the reverse reaction. 23. In the endothermic reaction with increasing temperature equilibrium is shifted to the side: A) formation of the starting materials; B) formation of reaction products; C) direct reaction; D) the formation of by-products; E) the reverse reaction. 24. With increasing pressure for a reaction that goes with a decrease in volume, the equilibrium shifts to the side: A) formation of the starting materials; B) formation of reaction products; C) direct reaction; D) formation of intermediate products; E) the reverse reaction. 25. For an exothermic reaction, the equilibrium constant with increasing temperature: A) decreases;
B) increases; C) does not change; D) becomes minimal; E) becomes maximum. 26. For an endothermic reaction, the equilibrium constant with increasing temperature: A) decreases; B) increases; C) does not change; D) becomes minimal; E) becomes maximum. 27. A reactor in which all particles move in a given direction, completely displacing, like a piston, the particles in front of the flow is called: A) batch reactor; B) ideal mixing reactor; C) ideal displacement reactor; D) batch mixing reactor; E) ideal mixing reactor. 28. A reactor in which the incoming particles are instantly mixed with the particles in it and evenly distributed throughout the volume of the apparatus is called: A) ideal displacement reactor; B) total mixing reactor; C) contact device; D) autoclave; E) distribution chamber. 29. The reactor operating in the mode – loading of raw materials, their chemical transformation and unloading of the finished product – is called: A) batch reactor; B) continuous reactor; C) ideal mixing reactor; D) ideal displacement reactor; E) contact action reactor. 30. The reactor in which concentration of reagents smoothly changes on its height and respectively influences the change of speed of the reaction, is called: A) reactor of continuous action; B) reactor of ideal replacement; C) reactor of periodic action; D) the reactor with a complete mixing; E) tubular reactor.
31. The reactor, in which the concentrations at all points of the reaction volume are equalized by mixing, is called: A) continuous reactor; B) ideal displacement reactor; C) batch reactor; D) jet reactor; E) tubular reactor. 32. In order to achieve high degrees of transformation of the initial reagents in the reactor of complete mixing: A) increase in the reaction mixture; B) cascade of reactors with complete mixing; C) strengthening the mixing mode; D) ideal mixing mode; E) cascade of ideal displacement reactors. 33. CTS is a set of interconnected technological flows acting as a whole apparatus, in which the following sequence of operations is carried out: A) chemical transformations, selection of target products; B) preparation of raw materials for chemical transformations, chemical transformations; C) preparation of raw materials for chemical transformations, chemical transformations, isolation and purification of the target products; D) preparation of raw materials for chemical transformations, selection of the target product; E) chemical transformations. 34. In the composition and structure of the CTS, the functional subsystem that processes raw materials refers to: A) control subsystem; B) energy subsystem; C) technological subsystem; D) mechanical subsystem; E) subsystem of preparation. 35. In the hierarchical sequence of the composition and structure of the CTS, individual apparatuses are referred to: A) the first scale level; B) the second scale level; C) the third scale level; D) the fourth scale level; E) the fifth scale level. 36. In the hierarchical sequence of the composition and structure of the CTS units and assemblies are referred to: A) the first scale level;
B) the second scale level; C) the third scale; D) the fourth scale level; E) the fifth scale level. 37. The departments of chemical production in the structure of the CTS refer to: A) the third scale level; B) the second scale level; C) the first scale level; D) the fourth scale level; E) the fifth scale level. 38. Chemical production in a hierarchical sequence of the structure of the CTS on a scale level refers to: A) the third scale level; B) the second scale level; C) the first scale level; D) the fourth scale level; E) the fifth scale level. 39. The elements of the CTS are classified as intended. Elements that move, change the shape and size of the material are referred to as: A) chemical; B) hydro-mechanical; C) mass transfer; D) mechanical; E) technical. 40. Complete the definition: «... technological communication is a scheme with an open circuit, in which the flow leaving this element is incoming for the subsequent element». A) consistent; B) consistently – bypass; C) parallel; D) reverse (recycle); E) cyclical. 41. The most economically expedient technological process: A) semi-continuous; B) continuous; C) discontinuous; D) cyclic; E) combined.
42. The set of basic parameters affecting the speed of the process, the yield and quality of the product is called: A) technological mode; B) technological balance; C) capital costs; D) technical and economic balance; E) economic regime. 43. An apparatus, in which processes are carried out combining chemical reaction with diffusion mass transfer stages, is called: A) a synthesis column; B) an oven; C) a desiccator; D) a chemical reactor; E) a filter. 44. The set of interacting devices in which physical and chemical processes are carried out in order to process raw materials into final products is called: A) a technological system; B) a chemical system; C) a chemical-technological system; D) a closed system; E) a production system. 45. A consistent description of the processes and the corresponding devices that make up the chemical-technological system is called: A) a technological scheme; B) a chemical scheme; C) a physical scheme; D) a description of the process; E) a description of the devices. 46. The process of gas absorption by liquids with the formation of solutions is called: A) distillation; B) absorption; C) rectification; D) sublimation; E) adsorption. 47. The process of simple separation of a mixture of volatile liquids having different boiling points by evaporation followed by vapor condensation is called: A) sublimation; B) distillation; C) rectification; D) evaporation; E) drying.
48. The process based on repeated evaporation of liquid and condensation of its vapors in counterflow interaction with vapors rising from the bottom and the liquid (phlegm) which is flowing down from from the top of the column is called: A) rectification; B) distillation; C) fractionization; D) sublimation; E) evaporation. 49. Thermal processing of flammable materials without air access is called: A) pyrolysis; B) isomerization; C) aromatization; D) carbonization; E) thermal cleavage. 50. The process of absorption of gases by the surface of a solid absorber – the sorbent is called: A) adsorption; B) saturation; C) sorption; D) absorption; E) gasification. 51. Transformation of solid crystalline substances into vapors, bypassing the melting stage, is called: A) sublimation; B) evaporation; C) softening; D) liquefaction; E) boiling. 52. Transformation of solid crystalline substances into vapors, bypassing the melting stage, is called: A) sublimation; B) evaporation; C) gasification; D) liquefaction; E) softening. 53. The processing of solid materials at high temperature in order to isolate useful components and impart mechanical strength to them is called: A) smelting; B) heat treatment; C) roasting; D) distillation; E) sublimation.
54. Production of solid porous pieces of dust-like or powdery materials when heated below the melting temperature is called: A) fusion; B) sintering; C) agglomeration; D) slag formation; E) ashing. 55. Substances that increase the activity of the catalyst are called: A) accelerators; B) inhibitors; C) promoters; D) hardeners; E) crystallizers. 56. Substances that increase the activity of the catalyst are called: A) activators; B) inhibitors; C) structuring agents; D) fixers; E) initiators. 57. Heat-resistant porous substances, which in one way or another are applied to the catalyst, are called: A) activators; B) promoters; C) carriers or triggers; D) sorbents; E) substrates. 58. Chemical-technological process consists of the following elementary stages: A) loading of reacting components into the reactor; B) preparation and loading of raw materials, chemical interaction, unloading and cleaning of the target product; C) unloading of products from the reactor, storage; D) reagent supply to the reaction zone, chemical interaction, removal of products from the reaction zone; E) the chemical interaction itself. 59. A heterogeneous system corresponds to the equation: А) 2HBr = H2 + Br2; В) 4Н2О + 3Fe = 4H2 + Fe3O4; С) N2O4 = 2NO2; D) 2СО + О2 = 2CО2; Е) CO + Н2O(vapor) = Н2 + CO2.
60. A heterogeneous system corresponds to the equation: А) 2NO + O2 = 2NO2; В) 3Н2 + N2 = 2NH3; С) 2Al + 3Cl2 = 2AlCl3; D) 2SO2 + O2 = 2SO3; Е) CO + Н2O(vapor) = Н2 + CO2. 61. How many times will the speed of a chemical reaction increase with an increase in temperature by 30 °C, if the temperature coefficient of the reaction rate is 3? A) 3; B) 9; C) 10; D) 27; E) 30. 62. How many degrees is it necessary to raise the temperature to increase the reaction rate by 16 times, if the temperature coefficient of the reaction rate is 2? A) 32; B) 8; C) 40; D) 4; E) 25. 63. Two reactions at 10°C proceed with the same speed (υ1= υ2). The temperature coefficient of the speed of the first reaction is 2, the second is 3. How will the reaction rates υ1/υ2 be related if they are carried out at 30 °C? A) 8/27; B) 2/3; C) 3/2; D) 9/4; E) 27/8. 64. The expression of the law of mass action for the process 2SO2 + O2 = 2SO3 corresponds to: А) V = k[2SO2][O2]; В) V = k[SO2][O2]; С) V = k[SO2][2O2]; D) V = k[SO2]2[O2]; Е) V = k[SO2]3[O2]. 65. The dependence of the speed of reaction on concentration of the reacting substances is expressed by the law: A) Van’t Hoff’s law; B) the law of constancy of the composition;
C) the law of masses; D) Raul’s law; E) Avogadro’s law. 66. An increase in the concentration of NO by 2 times in the reaction 2NO + O2 = 2NO2 leads to an increase in the reaction rate by n times: А) 2; В) 4; С) 5; D) 3; Е) 6. 67. An increase in the concentration of nitrogen by a factor of 2 in the reaction N2 + 3H2 = 2NH3 leads to: A) an increase in the reaction rate by 2 times; B) a reduction of the reaction rate by 3 times; C) a reduction of the reaction rate by 6 times; D) a reduction of the reaction rate by 8 times; E) an increase in the reaction rate by 6 times. 68. An increase in the concentration of hydrogen by 3 times in the reaction N2 + 3H2 = 2NH3 leads to: A) an increase in the reaction rate by 27 times; B) an increase the reaction rate by 9 times; C) an increase in the reaction rate by 3 times; D) a reduction of the reaction rate by 9 times; E) a reduction of the reaction rate by 17 times. 69. An increase in the concentration of ammonia by 3 times in the reaction 4NH3 + 5О2 = 2NO + 6Н2О results in: A) an increase in the reaction rate by 3 times; B) an increase in the reaction rate by 27 times; C) an increase in the reaction rate by 23 times; D) an increase in the reaction rate by 15 times; E) an increase in the reaction rate by 10 times. 70. An increase in the concentration of oxygen by 3 times in the reaction 2СuS + 3О2 = 2СuО + 2SО2 results in: A) an increase in the reaction rate by 9 times; B) an increase in the reaction rate by 25 times; C) an increase in the reaction rate by 3 times; D) a reduction of the reaction rate by 9 times; E) a reduction of the reaction rate by 25 times. 71. An increase in the concentration of SO2 by a factor of 3 in the reaction 2SO2 + O2 = 2SO3 leads to: A) an increase in the reaction rate by 9 times;
B) a reduction of the reaction rate by 9 times; C) a reduction of the reaction rate by 8 times; D) a reduction of the reaction rate by 3 times; E) an increase in the reaction rate by 3 times. 72. An increase in the oxygen concentration by a factor of 2 in the reaction C2H4 + 3O2 = 2CO2 + 2H2O leads to: A) an increase in the reaction rate by 2 times; B) an increase in the reaction rate by 6 times; C) a decrease in the reaction rate by 6 times; D) an increase in the reaction rate by 8 times; E) a reduction of the reaction rate by 8 times. 73. Reducing the oxygen concentration by 2 times in the reaction СuS + + 3О2 = 2СuО + 2SО2 results in: A) an increase in the reaction rate by 2 times; B) a decrease in the reaction rate by 2 times; C) an increase in the reaction rate by 9 times; D) a reduction of the reaction rate by 6 times; E) a reduction of the reaction rate by 8 times. 74. Increasing the concentration of sulfur oxide (ІV) by 2 times in the reaction 2SO2 + O2 = 2SO3 results in: A) an increase in the reaction rate by 2 times; B) a reduction of the reaction rate by 3 times; C) an increase in the reaction rate by 3 times; D) an increase in the reaction rate 9 times; E) a reduction of the reaction rate by 9 times. 75. For the reaction 2X + Y = Z with Cx = 1.0 mol/L and Cy = 2.5 mol/L, the reaction rate is 0.5 mol/(L·h). Calculate the reaction rate constant: A) 0.01; B) 0.005; C) 0.2; D) 0.3; E) 0.05. 76. For the reaction A + B = R + D at CA = 1 mol/L and CB = 2 mol/L, the rate is 0.5 mol/ L·h. Determine the reaction rate constant: A) 0.15; B) 0.40; C) 0.60; D) 0.40; E) 0.25.
77. For the chemical reaction A + 2B + C = D, the dependence of the rate on the concentration of the reacting substances corresponds to: A) V = K·CA·CB2·CD; B) V = K·CA·CB·СС; C) V = K·CA·CВ2; D) V = K·CA·CB2·CС; E) V = K·CB·CС. 78. The reaction rate A + 2B = C with an increase in the concentration of B will increase in N number of times: A) 9; B) 2; C) 3; D) 4; E) 12. 79. With an increase in the concentration of reactants, the reaction rate: A) will increase; B) will not change; C) will decrease; D) will shift to the left; E) will stop. 80. An increase in the ammonia yield by the reaction: N2 + 3H2 = 2NH3 + Q will contribute to the condition: A) increase in the pressure in the system; C) temperature rise; C) reduction of hydrogen concentration; D) lowering of the system pressure; E) reduction of nitrogen concentrations. 81. In the reaction 2NO + O2 = 2NO2 + Q, determine the numbers of factors that shift the equilibrium to the right: 1. an increase in the concentration of oxygen; 2. a reduction in the concentration of nitric oxide (II); 3. an increase in the temperature; 4. a reduction in the pressure; 5. a reduction in the temperature; 6. an increase in the pressure; 7. introduction of the catalyst. A) 1, 3, 5; B) 2, 4, 6; C) 1, 4, 5; D) 2, 5, 6; E) 1, 5, 7.
82. On the balance of which of the above reactions pressure does not affect: A) 2SO2 + O2 = 2SO3; B) 2H2 + O2 = 2H2O; C) N2 + 3H2 = 2NH3; D) N2 + O2 = 2NO; E) 2CO + O2 = 2CO2. 83. The balance of which of the processes will shift to the left with increasing pressure: A) H2 + I2 = 2HI; B) СО + Н2О(g) = СО2 + Н2; C) 2SO2 + O2 = 2SO3; D) Cl2 + CO = COCl2; E) NH4NO2 = 2H2O + N2. 84. The balance of which of the processes will shift to the right with increasing temperature: А) CO2 + 2Mg = 2Mg + C + Q; B) 2SO2 + O2 = 2SO3 + Q; C) 2CO + O2 = 2CO2 + Q; D) MgCO3 = Mg + CO2 – Q; Е) N2 + 3H2 = 2NH3 + Q. 85. For the reaction H2 + I2 = 2HI + Q define a balance shift condition towards formation of a product: A) increase in pressure; C) heating; C) pressure reduction; D) cooling; E) radiation. 86. With increasing pressure equilibrium in the reaction 2NO + O2 = 2NO2 will shift: A) towards the formation of the product; B) towards the formation of precursors; C) will not change; D) mainly to the right; E) mainly to the left. 87. The speed of a heterogeneous process:
1 dn A s dτ ; 1 dn A v dτ ;
A) W het B) W het
C) W het R 0 l D) Whet = Rm·ΔC; E) W het
1 dn A v dc .
88. Heterogeneous processes are processes in which: A) the components involved in the reaction are in different phases; B) reagents and products are in the same phase; C) the starting reagents are in one phase and the products are in another; D) the process is carried out on a solid catalyst; E) the components involved in the reaction are in the same phase. 89. A method for increasing the driving force of a heterogeneous process: A) increasing the concentration of reagents; B) grinding solids; C) intensive mixing; D) temperature increase; E) increase in selectivity. 90. The exothermic reactions are those for which ΔH and Qp correspond to the values: A) Н < 0, Qp > 0; B) Н > 0, Qp < 0; C) Н < 0, Qp < 0; D) Н > 0, Qp > 0; E) Н = 0, Qp < 0.
1.3. Raw materials, water and energy in chemical industry Raw materials of chemical production. Characteristics and reserves of raw materials. Principles of enrichment of raw materials. Complex use of raw materials. Secondary raw materials and their processing Raw materials are natural materials (initial substances) used in industrial production. The profitability of production, the choice of technology and the equipment and quality of the final products substantially depend on raw materials.
The scheme of modern chemical production includes the following components at various stages of processing: raw materials (initial reagents), semi-products (intermediate products), by-products, the target product and waste. A semi-product is a raw material that has been processed at one or several stages of production, but not processed into the target product. The semi-product obtained at the previous stage of production can be a raw material for the subsequent stage. A by-product is a substance that is formed during the processing of raw materials along with the target product, but is not the goal of this production. By-products resulting from the production or enrichment of raw materials, are called co-products (passing products). Production wastes are residues of raw materials, materials and semi-products formed in production, which have completely or partially lost their qualities. Semi-products, by-products and production wastes after or without additional processing can be used as raw materials for other processes. The raw materials for chemical production are the products of the oil, gas, coal, coke-chemical, pulp and paper, mining industries, ferrous and non-ferrous metallurgy, etc. Chemical raw materials are classified: – by origin: mineral, animal, vegetable, water, air; – by chemical composition: organic, inorganic; – by types of reserves: renewable, non-renewable; – by the state of aggregation. Mineral raw materials are divided into ore, non-metallic and fuel. Raw materials are also classified as primary (natural sources) and secondary (intermediate and by-products of industrial production and consumption, waste); natural and artificial (obtained as a result of industrial processing of natural raw materials). A number of requirements are imposed on raw materials, which should provide: – minimum of process stages; – minimum energy consumption; – minimum dissipation of the input energy; – minimum energy loss with products; 52
– reduction of process parameters (temperature, pressure) and energy consumption to change the state of aggregation of reagents; – a large yield of the target product. The share of raw materials in the cost of production of the chemical industry reaches 70%-80%. Therefore, the problem of resources and the rational use of raw materials during its processing and production is very important. In the chemical industry, as a raw material, compounds of more than 80 elements, contained in the earth’s crust, are used. Quantitative characterization of the prevalence of elements in nature is estimated in clarks. Clark is a quantity that expresses the content of elements in the earth's crust in mass or atomic percentages, or grams per ton. More than 98% of the mass of the crust is made of 9 elements (O, Si, Al, Fe, Ca, Na, Mg, K, H); all other elements account for only 1.87%. The carbon content is only 0.35% of the mass of the earth’s crust. Raw materials reserves are divided into identified (studied) and potential resources. According to the degree of knowledge and serviceability of the reserves of raw materials, they are divided into three categories: 1) A – reserves, explored in detail and prepared for development; 2) B – reserves established as a result of geological exploration; 3) C – reserves determined by the results of exploration and study of natural discoveries. The possibility of using raw materials for industrial production is determined by its value, availability and concentration of the useful component. The value of raw materials depends on the level of development of technology and the challenges facing production and varies significantly over time. For example, in the second half of the 20th century, uranium, which was previously a waste in the production of radium, became the most valuable strategic raw material. A significant impact on the ability to use reserves of raw materials has a concentration of useful element. Many elements with a relatively high content in the earth’s crust are dispersed, making it difficult to use their compounds as chemical raw materials. 53
The place of Kazakhstan in the world mineral complex By extraction and production of mineral and raw products Kazakhstan is ranked in the world: by chromites – the 2nd place, by titanium – 2-3 place, by zinc – 6, by manganese – 8, by lead – 6, by silver – 9, by uranium – 5, copper – 10, by oil, gas, coal and iron – Kazakhstan is included into 20 leading countries of the world. Kazakhstan plays an important role in the world market of copper, uranium, titanium, ferroalloys and steel, is a monopolist in the Euro-Asian subcontinent on chromium, has a significant influence on the regional (CIS countries, first of all – Russia) market of iron, manganese, coal and aluminum. Kazakhstan will be able to effectively manage its oil reserves and occupy a worthy place in the global oil market. The most qualitative and competitive raw material base is ferrous metallurgy. The share of active explored reserves of chrome ores in the state balance is 99%, manganese ores – 91%. A significant proportion of active reserves (96%) is characterized by developed iron ore deposits. The raw material base of non-ferrous metallurgy is characterized by significantly lower reserves activity. For lead, it is 69%, for copper – 74%, zinc – 92%. Almost all active proven reserves of copper are localized in the fields of Central and Eastern Kazakhstan, which are currently being actively exploited. About half of the active reserves of lead and zinc is enclosed in the fields of East Kazakhstan that are being developed or are being prepared for development. The other half of the potentially competitive reserves is concentrated in the Zhairem field in Central Kazakhstan, which is unique in scale and requires significant investment. The number of active reserves does not include the huge reserves of zinc and lead from the Shalkiya deposit (South Kazakhstan), whose ores are characterized by low quality and require the use of high-performance and efficient mining and processing schemes. In the gold ore industry, the activity of explored reserves is quite high – at the level of current prices, it exceeds 80 years. The share of active proven reserves of aluminum is 51% (with low quality), tin – 69% (Syrymbet deposit), coal – 45%, uranium – 61% (most deposits suitable for mining by leaching), and titanium – up to 48%, nickel – 34%. 54
Complex use of raw materials. Secondary raw materials and their processing The main areas of rational use of chemical raw materials are: – the use of cheaper raw materials (with minimal costs for extraction); – the use of secondary material resources (waste, by-products of other industries); – the use of less concentrated raw materials (poor ores); – complex processing of raw materials, that is, a method in which all valuable components contained in raw materials are extracted and used to the maximum extent. Complex use of raw materials allows us to approach the solution of the major problem of modern chemical technology – to minimize technological losses of raw materials and to completely use production wastes. It allows us to expand a source of raw materials, to increase the volume of the target products, to lower expenses on raw materials and energy and also to substantially reduce environmental pollution by industrial emissions. Complex use of raw materials leads to reduction of capital investments in production, to decrease in product cost and improvement of all technical and economic indicators of production. Preparation of raw materials for processing The purpose of preparation of raw materials is to give them a composition and properties that ensure the optimal course of the chemical process. Preparation of raw materials allows us to increase the concentration of the useful component, to obtain the desired humidity, determined by the processing conditions, the content of impurities, the desired dispersion, etc. Methods of preparation of raw materials depend on its state of aggregation. Solid raw materials are prepared by the methods of classification, grinding (or, in certain cases, consolidation), dehydration and enrichment. Classification is the process of separating homogeneous bulk materials into fractions (classes) by the size of their constituent particles. Classification is carried out by sieving materials (screening), separation of the mixture of particles by the rate of their deposition in the liquid phase (hydraulic classification), separation of the mixture of particles by the rate of their deposition in the air using separators (air classification). 55
Grinding is a mechanical process of dividing a solid body into parts due to application of external forces. Grinding can be carried out by impact, crushing and abrasion. Grinding of particles up to 10-3 m is called crushing and is carried out in crushers, from 10-3 to 10-6 m is called grinding (splitting) and carried out in mills. The measure of grinding is the degree of grinding, defined as: i = Dinitial / Dfinal, where: Dinitial and Dfinal are the average particle sizes (equivalent diameter) before and after grinding, respectively. In some cases, the preparation process includes the operation of consolidating the powdered material by briquetting or agglomeration methods. Dehydration is a method of runoff, settling and drying. Drying is the process of removing moisture or other liquid from solid materials by evaporation and removal of the generated steam. The drying condition is to ensure the inequality Pm > Pc, where Pm is the vapor pressure in the wet material being dried, and Pc is the partial pressure of vapor in the environment. The drying process is carried out in dryers of various designs, at atmospheric pressure or in vacuum. Enrichment is the process of separating the useful part of the raw material (useful component) from the waste rock (ballast) in order to increase the concentration of the useful component. As a result of enrichment, the raw material is divided into a concentrate of the useful component and tails with a predominance of waste rock in them. Quantitative indicators of the enrichment process are: 1. The concentrate yield is the ratio of the mass of the obtained concentrate тconcentrate to the mass of the enriched raw material menriched: ηconcentrate = тconcentrate/menriched 2. The degree of extraction of the useful component is the ratio of the mass of the useful component in the concentrate mcc to its mass in the enriched raw material mcr: 56
Xextraction = mcc/mcr 3. The degree of enrichment of raw materials is the ratio of the mass fraction of the useful component in the concentrate μcc to its mass fraction in the enriched raw materials μcr: Хо = μcc/μcr The choice of enrichment method depends on the state of aggregation and differences in the properties of the components of the raw materials. In the enrichment of solid raw materials mechanical, chemical and physico-chemical methods are used. The mechanical methods of enrichment include: – gravity method based on different sedimentation rates of particles of different density and size in a gas or liquid flow, or in a field of centrifugal force; – electromagnetic method based on different magnetic permeability of raw material components; – electrostatic method based on different electrical conductivity of the components of the raw material. Chemical enrichment methods include dissolution when gold is extracted by mercury or cyanide methods. The most common method of flotation belongs to the physicochemical enrichment methods. Flotation, where: WR – is waste rock, and firing, for example, in the preparation of iron from iron pyrites, is a method of enrichment of solid raw materials, based on the difference in the wettability of its components. The wettability of particles of a substance is characterized by the work of adhesion at the interface of the phases of the system «solidliquid» Wliquid-solid: Wliquid-solid = σliquid-gas + σsolid-gas + σliquid-solid where: σliquid-gas, σsolid-gas, σliquid-solid are specific free surface energies at the interface of the corresponding phases. The specific surface energy is proportional to the phase interface, that is, σ = f (F), therefore the smaller the particles of the 57
material being floated, the greater the ratio of their surface to the volume (s/v) or mass (s/m) and the stronger the wettability phenomenon. Therefore, the floatable raw material is ground to a size of 0.050.3 mm. An indicator of wettability of the material is the «edge wetting angle» at the interface of the phases «solid – liquid – air» between perpendicular to the surface of the liquid and tangent to the meniscus of its particles due to the fact that the surface tension forces tend to align the level of the liquid, particles of non-wettable or hydrophobic materials (0 > 90°) are pushed out of the liquid (float), and particles of wetted or hydrophilic materials (0 < 90°) are immersed in the liquid. To speed up the flotation process, the system is foamed by intensive mixing (mechanical flotation machines) or air bubbling through the system (pneumatic flotation machines). The result of flotation depends on the difference in the hydrophobicity (hydrophilicity) of the components of the enriched raw material. Therefore, in case that the useful component and the waste rock are close in wettability, special reagents belonging to the group of surfactants are introduced into the system, which increase the hydrophobicity of the useful component (collectors). Their nature depends on the composition of the particular floatable raw material. To create a stable foam and improve separation of components of the floated raw materials, in addition to the collectors, other flotation reagents are introduced into the system: activators, suppressors, frothers and pH regulators of the medium. The value of water in chemical technology. Industrial and sanitary water requirements. Industrial water treatment. Chemical, mechanical, physico-chemical and biological methods of water purification from impurities. Desalting and desalination of water. Ways of water circulation in industry
Water is one of the main and popular raw materials of chemical and technological production. Water resources are natural surface and underground waters, waste waters of technological productions demand careful preliminary special preparation and cleaning. The most common methods of water treatment are: – primary sedimentation (with/without reagents, depending on its composition); 58
– coagulation by introducing salts of aluminum, iron or polyelectrolytes into the water to be purified in order to enlarge suspended and colloidal particles and transfer them to a filterable form; – mechanical water purification by filtration; – special wastewater treatment of enterprises using chemical, physico-chemical and biochemical methods. Industrial water treatment is carried out using mechanical, physical, chemical and physicochemical methods, such as clarification, softening, ion exchange, desiliconization, degassing, etc. For the clarification of water, methods based on the sedimentation of impurities released from water in the form of sediment are used. They are also called reagent methods, since special reagents are introduced into the water to separate them. Industrial deposition processes include coagulation, liming, and magnesia desiliconization, which are used to clarify water. Requirements for water, depending on its purpose, are established by the State Standards. If water coming from a water source does not meet the requirements of the relevant State Standard, it is sent for water treatment. Water is used in industrial production to solve a large number of problems. It plays the role of working agent in the cycle of steam machines and steam-water vacuum refrigeration machines. It is widely used for heat supply as a heat carrier (heating, heating of various materials, liquids, etc.) and for its removal (cooling of reaction apparatuses, internal combustion engines and compressors, etc.). With the addition of salts such as NaCl and CaCl2, water is used as a brine to remove heat at temperatures below 0 ºC. It also serves as a working fluid to transfer pressure during hydraulic strength and permeability testing of various pipes, to transfer work in hydraulic presses. Water is used for transportation of eroded soil, rock, peat, slag, ash, chemical intermediates and other purposes. Water is also used as a technological component for leaching, dissolution, as a medium for chemical processes. The requirements for the quality of water in industrial production are mainly reduced to the fact that impurities should not interfere with or harm its industrial use. Water should not cause corrosion of the equipment, boilers, pipes, equipment, various mechanisms, 59
and also should not contain excess of the weighed substances clogging channels of cooling system, to clog and wear out details of presses, pumps, pipes, to spoil production. Salts and other impurities that cause water hardness can form on the working surfaces of heat-power, water-heating and cooling plants scum (salt deposits that conduct little heat). This leads to damage to metal surfaces, reduces the vacuum in the condensers of turbines, increases the temperature of flue gases, impairs the operation of heat exchangers, which leads to fuel overruns and increased costs associated with the need to repair production equipment. Classification of natural waters by the content of impurities Natural water contains many organic and inorganic substances, which depending on the particle size can be divided into three groups: suspended or coarse (more than 100 nm), colloidal (from 1 to 100 nm), true or molecular dispersed (less than 1 nm). According to the chemical composition, impurities are divided into organic (complex in composition in colloidal or truly dissolved state) and inorganic (ions Na+, Ca+2, Mg2+, K+, Cl–, HCO3– and gases N2, CO2, O2). In accordance with sanitary rules and norms of protection of surface waters from pollution, the oxygen content in the water should be at least 4 mg/l at any time of the year. Removal of oxygen from water is carried out by deaeration and chemical reduction. Deaeration is based on the use of Henry’s law: С = К·Р, where P is the partial pressure of the gas above the surface of the liquid, kg / cm2; C is the oxygen concentration ml/l; K is Henry constant, solubility coefficient, mg/(l · kgf/cm2). In open systems with fresh water in the presence of oxygen with temperature up to 60-70 ºС, corrosion occurs, which then decreases due to a decrease in the solubility of oxygen in water. In a closed system, corrosion does not decrease with increasing temperature. The oxygen corrosion process is particularly intense at pH < 7. 60
It is possible to reduce the solubility of oxygen in water by lowering its partial pressure. This is achieved by reducing the total gas pressure or by displacing one gas with another. For example, water is purged with water vapor, and then degassed using thermal deaerators, in which the condensate and additional water are brought to a boil at an excess pressure of 2-4 kgf / cm2. The deaeration method fails to provide deep oxygen removal, therefore, chemical methods are also used. To bind the residual oxygen, sodium sulfite is used: 2Na2SO3 + O2 = 2Na2SO4 The method is accompanied by an increase in total salinity, which is not always desirable. The most common reagents are hydrazine hydrate and hydrazine sulfate (N2H4·H2SO4, which are strong reducing agents: N2H4 + O2 = N2 + 2H2O. The disadvantage of hydrazine is its high toxicity. Classification of water by the content of mineral salts The most common classification method is to assess the content of inorganic and partially dissolved organic substances in water. The total amount of substances dissolved in water (mineralization) is usually determined by the weight of the dry residue of the pre-filtered and evaporated sample after drying to a constant weight at a temperature of 105 ºC. According to the magnitude of mineralization, natural waters are divided into eight types or classes. Quality drinking water should contain no more than 0.5 g/l of salts. Ultra fresh water has the ability to remove calcium compounds from the human body, so it is not quite suitable for use in drinking purposes. Classification of natural waters by hardness The most important characteristic of water, which largely determines the possibility of its use, is its hardness. Hardness is determined by the content of calcium and magnesium ions in the water. It is measured in mol-eq/m3 (mol/m3) or mmol-eq / l (mmol/l). 61
According to the value of the total hardness, natural waters, as a rule, are divided into a number of groups: – very soft water (10.7 mol/m3). Among natural waters, the softest one is rainwater, the hardness of which is approximately 0.070-0.1 mol/m3. The hardness of groundwater varies widely from 0.7 mol/m3 to 18-20 mol/m3 and depends on the composition of the rocks in contact with them. In industrial production, there are three types of wastewater: – production (production water contaminated with insoluble and soluble substances, sometimes heated); – domestic (water from domestic premises located at enterprises); – surface (sedimentary water). Industrial waters are formed by direct evaporation of water in the technological and production process, during transportation of materials, during washing and water cooling of equipment. Water used for cooling, as a rule, acquires only thermal pollution, i.e. it has an increased temperature. The wastewater quantity allotted per unit time from source (install, workshop, production), is called the flow of wastewater and is determined depending on the performance of the source according to the norms of sanitation. The norm is the average amount of wastewater per m3 required to produce a unit of finished product or to process a unit of raw materials used. Technological and enlarged water recovery rates are distinguished. Waste water flow rate is determined by the formula: Qday = M·N, where M is the number of units of product or processed raw materials per day; N is the rate of water disposal per unit of production or processed raw materials (m3 / unit of production) The degree of pollution of wastewater is characterized by water quality – a set of physical, chemical, biological and bacteriological indicators. 62
These include: – T ºC; – odour; – chromaticity; – Pt-Co gradient scale (PCSh); – the concentration of hydrogen ions (pH); – the concentration of suspended solids mg/l (mg/m3); – dry and calcined residue, reflecting the total content of solutes and its mineral part mg/l (g/m3); – BOC (biological oxygen consumption); – ChOC (chemical oxygen consumption) mg/l (g/m3); – the content of components specific to this type of production, for example, phenols, turpentine, etc. mg/l (g/m3). The quantity and quality of industrial wastewater depends on: – the type of raw materials and products produced; – production capacity; – standards of sanitation; – specific consumption of fresh water per unit of production; – perfection of technological process; – completeness of waste production, – variety and type of equipment used; – equipment of process control and instrumentation, etc. There are sanitary and hygienic requirements for the MPC of pollutants in industrial wastewater. The water quality standard includes MPC, physical, chemical and biological composition of wastewater and their properties that meet the requirements of different consumers. Such properties include: – temperature, – suspended solids, – mineralized (dry residue), – chlorides, – sulfates, – dissolved oxygen, – pH, – BOC, – pathogens, – toxic substances and many others. 63
Assessment of the content of various chemicals in water is carried out according to the MPC set for more than 700 chemical compounds. Standards on the composition and properties of industrial waters are established for two categories of water use: 1) economic-drinking and cultural-household water use; 2) fisheries water use. Water treatment is a complex of operations to remove harmful impurities from natural water. Water treatment includes operations of clarification, softening, degassing, and in some cases desalination and disinfection for drinking water. Water clarification is achieved by its sedimentation, followed by its filtration through granular material of various dispersions. To coagulate colloidal impurities and absorb colored substances contained in water, electrolytes, aluminum and iron sulfates are added to it. Water disinfection is provided by its chlorination or ozonation. Degassing is the removal of dissolved gases from water by a chemical method in which gases are absorbed by chemicals, for example, in the case of carbon dioxide: СО2 + Са(ОН)2 = СаСО3 + Н2О, or by physical methods of thermal deaeration in air or in vacuum. Desalination is used in those industries where particularly stringent purity requirements are imposed on water, for example, in the preparation of semiconductor materials, chemically pure reagents, and pharmaceuticals. Desalination of water is achieved by ion exchange, distillation and electrodialysis. The ion exchange method is based on the property of some solids (ion exchangers) to absorb ions from solution in exchange for an equivalent amount of other ions of the same sign. Ionites are divided into cation exchangers and anion exchangers. Cation exchangers contain mobile sodium or hydrogen cations, while anion exchangers contain mobile hydroxyl ions. Sulfonated coal, aluminosilicates (permutite, zeolite, etc.) are used as cation exchangers, artificial resins, for example, urea resins, are used as anion exchangers. Accordingly, the processes of ion exchange are divided into: – H(Na)-cationization, for example: Na2[Cat] + Ca(HCO3) → Ca[Cat] + 2Na2CO3, 64
– anionization, for example: An [OH] + HC1 → An [C1] + H2O, where: [Cat] and [An] is the ion exchange matrix not participating in the exchange. Since the ion exchange process is reversible, the establishment of equilibrium in the system means the termination of the desalination process. The absorption capacity of an ion exchanger is characterized by its exchange capacity equal to the number of calcium and magnesium ions, which can be absorbed by a unit of the volume or mass of the ion exchanger, expressed in gram equivalents: g-eq / m3 and g-eq / kg. The duration of the working cycle of ion exchange filters depends on the exchange capacity for a given volume of ion exchanger. When the ion exchanger is saturated, it can be regenerated by washing with solutions for H acid cation exchangers, Na sodium chloride cation exchangers, and for anion exchangers with an alkali solution. In the above examples of the operation of anion exchangers, the following reactions occur: Са [Cat] + 2NaCl → Na2 [Cat] + СаС12 and [An] Сl + КОН →[An] ОН + КСl. One of the main and mandatory operations for the water treatment of process water is its softening. Softening is the treatment of water to reduce its hardness, that is, to reduce the concentration of Ca+2 and Mg+2 ions by various physical, chemical and physicochemical methods. In the physical method, water is heated to boiling, as a result of which soluble calcium and magnesium bicarbonates are converted into their carbonates, which precipitate: Са(НСО3)2 = СаСО3 + Н2О + СО2. This method removes only temporary hardness. Chemical softening methods include phosphate and lime-soda, consisting in the 65
treatment of water with trisodium phosphate or a mixture of calcium hydroxide and sodium carbonate. In the first case, the reaction of formation of insoluble tricalcium phosphate precipitates is: 3CaSО4 + 2Na3PО4 = 3Na2SО4 + Ca3(PО4)2. In the second case, two reactions proceed. Calcium and magnesium bicarbonates react with calcium hydroxide, thereby eliminating temporary hardness: Са(НСО3) + Са(ОН)2 = 2СаСО3 + 2Н2О, and sulfates, nitrates and chlorides – with sodium carbonate, which eliminates constant hardness: CaSО4 + Na2CО3 → CaCО3 + Na2SО4. Energy intensity of chemical production. Types and sources of energy. Alternative energy source. The essence of complex energychemical use of fossil fuels and heat of exothermic processes, regeneration and reuse of energy. Energy technology schemes. Secondary energy resources. The concept of full use of energy re-sources. Regeneration, utilization of heat and energy Chemical production is one of the most energy-intensive. This is the production of ammonia, phosphorus, calcium carbide, sodium carbonate, chemical fibers and plastics, which makes up more than 60% of the electric and 50% of the thermal energy of the entire industry. The energy consumption of chemical production is estimated by its energy intensity. Energy intensity of production is the amount of energy spent on obtaining a unit of production. It is expressed in kW·h (kJ) or in tons of conventional fuel (CF) per ton of production. According to energy intensity chemical production is divided into three classes: 1) Production with conventional fuel (CF) consumption of more than 2 tons (58-103 kJ) per ton of production. These include the production of chemical fibers, acetylene, caprolactam, polyethylene, acrylonitrile, etc. 66
2) Production with conventional fuel (CF) consumption from 1 to 2 tons (29·103 – 58·103 kJ) per ton of production. These include the production of sodium carbonate, ammonia, calcium carbide, methanol, etc. 3) Production with conventional fuel (CF) consumption of less than 1 ton (29·103 kJ) per ton of product. These include the production of diluted nitric acid, ethylene glycol, acetic acid, aniline, polystyrene, double superphosphate, etc. The energy intensity of individual industries varies very widely: from 20·103 kWh for aluminum to 60-100 kWh for sulfuric acid per ton of products. Energy is used for chemical reactions, compression of gases and liquids, heating of materials, implementation of thermal processes (rectification, evaporation, etc.), mechanical and hydrodynamic processes (grinding, filtering, etc.), transportation of materials. Electric, thermal, fuel, mechanical, light, nuclear and chemical energy is used. The energy of electricity is used to conduct electrochemical, electrothermal, electromagnetic and electrostatic processes, as well as to move materials and actuate various mechanisms and machines. Thermal energy is used for various purposes. High potential energy (more than 623 K) is used for high-temperature processing of raw materials (firing, etc.) and intensification of chemical reactions. It is obtained by burning various types of fuel directly in technological devices. Thermal energy of medium (373–623 K) and low (323–423 K) potential is used in production processes associated with changes in the physical properties of materials (heating, melting, distillation, evaporation), for heating components in chemical processes, and also for some chemical processes. Heat transfer is carried out due to the contact of the heated system through the wall of the apparatus with a coolant having a high heat content or in direct contact with the heated material. A heat carrier is a substance or a system of substances used as a medium for heating. As heat carriers for medium – and low-temperature processes in the chemical industry, hot air, hot water, saturated and superheated water vapor, flue gases, high-boiling organic compounds, solid granular materials (usually catalyst grains) are used. 67
Fuel energy during fuel combustion is used to produce heat and electricity in thermal power plants and special-purpose furnaces and makes up about 50% of the total energy balance used in the chemical industry. Mechanical energy is used to perform such physical operations as grinding, centrifuging, moving materials, displacement, in the operation of various compressor machines, pumps and fans, etc. Light energy is used in the form of irradiation to conduct photochemical synthesis processes, for example, in the production of hydrogen chloride, halogen alkanes, etc. Chemical energy is used in the work of chemical current sources of various devices and purposes. Nuclear energy is used for conducting radiation-chemical processes (for example, in polymerization processes), energy production in nuclear power plants, for analysis, control and regulation of production processes. Of all the energy consumed by the chemical industry, 40% is electric, 50% is thermal (in the form of heat carriers steam and water) and 10% is fuel energy. The main sources of energy are fossil fuels and products of their processing, water energy, biomass and nuclear fuel. To a much lesser extent, the energy of the wind, sun, tides, geothermal energy is used. The world reserves of the main types of fuel are estimated at 1.28·1013 tons of CF (conditional fuel), including fossil coal 1.12·1013 tons, oil 7.4·1011 tons and natural gas 6.3·1011 tons of CF (conditional fuel). Energy production on the planet at present is 2.93·1014 kW·h or 3.35·107 MW·year. All energy resources are divided into primary and secondary, renewable and non-renewable, fuel and non-fuel. Fuel energy resources are: coal, oil, natural gas, shale, tar sands, peat, biomass. Non-fuel energy resources are: hydropower, wind, sun, earth, etc. Secondary energy resources (SER) are the energy potential of final, by-products and intermediate products and wastes of chemical production used for power supply of units and installations. These include the thermal effects of exothermic reactions, the heat content of the process waste products, and the potential energy of compressed gases and liquids. 68
The most important source of energy is chemical fuel (fossil coals, peat, petroleum products, natural and technical gases), which make up 70% of the balance of energy resources of the chemical industry. The structure of chemical fuel consumption is as follows: gas 19.4%, solid fuel 30.9%, petroleum products 47.2%. The calorie equivalent characterizes the energy value of a chemical fuel and represents the ratio of the net calorific value of a given fuel to the calorific value of conventional fuel (CF), taken as 29,260 kJ: ɳc = Qn/29,260 CF (conventional fuel) is the amount of energy in kW·h obtained from the complete combustion of 1 kg or 1 nm3 of fuel. This value is: for coal 8.0, natural gas 10.6, coke 7.2, fuel oil 15.4, reverse coke oven gas 4.8. For comparison, the same value for enriched uranium is 22.5·106. The second place in terms of the energy contribution is occupied by hydropower (HPP) and nuclear energy (NPP). The share of energy generated by hydropower plants is about 12%. NPPs represent the most promising source of energy, both electric and thermal. Renewable energy sources are: – hydropower; – wind energy; – tidal energy; – geothermal energy. Hydrogen as a source of energy and fuel: – contained in the lithosphere (17 hydrogen atoms per 100 other atoms) and practically inexhaustible reserves in water; – high energy content 3.5 times exceeding the energy content of oil; – simplicity and low cost of transportation (hydrogen transmission is cheaper than electricity transmission); – environmental cleanliness of combustion products. Low-cost production of hydrogen: electrolysis of water, pyrolysis of water in a plasma torch, biomass treatment with water vapor, photodegradation of water in the presence of enzymes, thermochemical and thermoelectrochemical cycles of water decomposition. 69
The criterion of economical use of energy of all kinds is the energy use coefficient equal to the ratio of the amount of energy theoretically necessary for the production of a unit of production (Wτ) to the amount of energy practically spent on it (Wp). η = Wτ /Wp For high-temperature endothermic processes, the heat energy utilization coefficient does not exceed 0.7, that is, up to 30% of the energy is consumed with the reaction products in the form of heat losses. The rational use of energy in chemical production means the application of methods that increase the coefficient of energy use. These methods can be reduced to two groups: 1) development of energy-saving technologies; 2) improvement of energy use in production processes. The first group of measures includes: – development of new energy-efficient technological schemes; – increased activity of the catalysts; – replacement of existing methods for separating production products into less energy-intensive ones (for example, rectification for extraction, etc.); – creation of combined power technological schemes uniting the technological operations proceeding with allocation and absorption of energy (heat). The second group of energy saving measures includes: – reduction of heat losses due to effective thermal insulation and reduction of the radiating surface of the equipment; – reduction of resistance losses in electrochemical industries; – use of secondary energy resources (SER). SER (secondary energy resources) are divided into: – combustible (fuel), representing the chemical energy of waste from technological processes of fuel processing and combustible metallurgy gases; – thermal SER, representing the physical heat of the exhaust gases and liquids of technological units and waste from the main production; – SER of overpressure, representing the potential energy of gases and liquids released from process units operating under overpressure. 70
Directions for the use of SER (secondary energy resources): – fuel; – thermal; – power to generate mechanical or electrical energy; – combined. TEST TASKS 1. Natural raw materials are classified as: A) available; B) secondary; C) primary; D) consumed; E) limited. 2. Intermediate, by-products and industrial wastes are classified as: A) artificial raw materials; B) secondary raw materials; C) primary raw materials; D) renewable raw materials; E) non-renewable raw materials. 3. Primary sources of energy include: A) fossil liquid fuels; B) waste heat carriers; C) hot vent emissions; D) hot process streams; E) used fuel oils. 4. Secondary energy sources include: A) fossil fuel oil; B) wood; C) waste heat carriers; D) hot thermal waters; E) fossil fuels. 5. Renewable energy sources are: A) river energy; B) shales; C) coals; D) natural gas; E) oil. 6. Non-renewable energy sources are: A) river energy;
B) the energy of the sun; C) natural gas; D) wind power; E) hydrothermal energy. 7. Hot process streams are referred to the following energy sources: A) secondary; B) primary; C) renewable; D) non-renewable; E) intermediate. 8. Heated ventilation emissions are attributed to the following energy sources: A) secondary; B) primary; C) primary renewable; D) primary non-renewable; E) secondary renewable. 9. Water in chemical processes is used as a cooler: A) as a heat exchanger; B) as a reagent; C) as a wash liquid; D) as a solvent; E) as absorbent. 10. Process water is used: A) as a reagent; B) in heat exchangers; C) to produce steam; D) as a solvent; E) all of the above is true. 11. The salt content in one liter of fresh water is: A) up to 7 g; B) up to 5 g; C) up to 1 g; D) up to 10 g; E) up to 100 g. 12. Desalination and softening of water includes: A) removal of salts of magnesium, calcium, etc.; B) upholding; C) filtration; D) degassing; E) ozonation.
13. The main components of chemical production: A) raw materials, energy, water; C) raw materials, catalyst; C) catalyst, energy, solvent; D) energy, water, solvent; E) raw materials, fuel. 14. The proportion of oxygen in the air is: A) 98%; IN 3%; C) 50%; D) 78%; E) 21%. 15. The proportion of nitrogen in the air is: A) up to 21%; B) 35%; C) 50%; D) up to 78%; E) 100%. 16. The flotation process is based on the phenomenon of: A) absorption; B) coagulation; C) selective extraction; D) dissolution; E) selective wetting. 17. The process of preparing raw materials, which is aimed at increasing the useful component in it, is called: A) concentration; B) depletion; C) precipitation; D) laundering; E) enrichment. 18. Raw materials for coke production: A) coal; B) oil shale; C) semi-coke; D) pyrites; E) gas oil. 19. Temporary hardness of water is determined by the salt content: A) calcium and magnesium bicarbonates; B) calcium and magnesium carbonates;
C) calcium and magnesium sulfates; D) calcium and magnesium chlorides; E) calcium and magnesium nitrates. 20. Slaked lime is: A) Ca(NO3)2; B) Cu(OH)2; C) Ca(OH)2; D) CaCl2; E) CaSO4. 21. «Lime milk» is called: A) CaO powder; C) Ca(OH)2 powder; C) an aqueous solution of Ca(OH)2; D) CaCO3 solution; E) a solution of Ca(NO3)2. 22. Temporary hardness of water can be eliminated by the following method: A) filtration; C) upholding; C) boiling; D) distillation; E) acidification with reagents. 23. During the firing of 3 kg of calcium carbonate, 550 L of carbon dioxide were released, measured under normal conditions. The mass fraction of decomposed calcium carbonate is: A) 82%; B) 80%; C) 99%; D) 87%; E) 95%. 24. In the production of NH3, water is used as: A) a source of hydrogen; B) a refrigerant; C) a coolant; D) a solvent; E) a reagent. 25. The content of which ions determines the constant hardness: A) Na+, K+, Cl¯; B) Na+, Ca2+, Mg2+, Cl¯; C) SO42-, Cl¯, Ca2+, Mg2+; D) Ca2+, Mg2+, HCO3; E) Ca2+, Mg2+, HCO3, H+;
26. What water hardness is eliminated by this reaction 2NaAlSiO4 + CaCl2 = Ca(AlSiO4)2 + 2NaCl? A) temporary; B) carbonate; C) resistant; D) average; E) general. 27. Cation exchange resin to eliminate water hardness corresponds to the formula: A) [Cat+]An¯; B) [An¯] Cat+; C) [CatAn]; D) [CatAn]An¯; E) H [Cat]. 28. When boiling water, the following reaction occurs: A) Ca(HCO3 ) 2 CaCO3 H2O CO2 ; В) Ca ( HCO 3 ) 2 Ca (OH ) 2 CaCO 3 2H 2 O; С) Ca (OCI ) 2 CO 2 H 2 O CaCO 3 2HCIO; D) CaCI2 Na2CO3 2NaCI CaCO3 ; E) Ca(HCO3 ) 2 CaO H 2 O CO2 . 29. The constant water hardness is due to the content in water of: A) calcium and magnesium bicarbonates; B) bicarbonates and sulfates of calcium and magnesium; C) chlorides, sulfates, sodium nitrates; D) chlorides, sulfates, calcium and magnesium nitrates; E) sodium and potassium bicarbonates. 30. Temporary hardness of water is due to the content in water of: A) calcium and magnesium bicarbonates; B) sodium and potassium bicarbonates; C) chlorides, sulfates, calcium and magnesium nitrates; D) chlorides, sulfates, sodium nitrates; E) bicarbonates and chlorides of calcium and magnesium. 31. Water hardness is determined by: A) the content of salts of calcium and magnesium; B) the content of alkali metal sulfates; C) chloride content; D) borate content; E) the content of nitrates and sulfates of metals.
32. The equilibrium constant of the nitrogen oxidation reaction by air depends on: A) temperature; B) the concentration of nitrogen; C) the concentration of nitric oxide; D) heat effect; E) the concentration of oxygen. 33. The method of separation of gas mixtures into individual components is: A) absorption-desorption; B) chemical; C) thermal; D) mechanical; E) diffusion. 34. In the adsorption method, such solid sorbents are used: A) zeolites, bauxites; B) activated carbon, aluminum oxide; C) activated carbon, zeolites, silica gel; D) silica gel, pumice, coal; E) pumice, coal, diatomite. 35. The main factor affecting the purity of the product is: A) composition of raw materials; B) aggregate state; C) crystal structure; D) the content of impurities; E) moisture content. 36. To determine the concentration of a substance in a solution by constructing a calibration graph, a linear dependence is constructed: A) A = f (C); B) A = f (T); C) A = f (w); D) A = f (ελ); E) A = f (l). 37. The method of separation of one of the components of the solution using an immiscible organic solvent is called: A) absorption; B) rectification; C) extraction; D) adsorption; E) distillation.
38. The method of separation of substances using inorganic and organic collectors that remove impurities is called: A) crystallization method; B) coprecipitation method; C) distillation method; D) extraction method; E) recrystallization method. 39. Distillation methods are: A) distillation, rectification; B) sublimation; C) boiling; D) drying; E) dissolution. 40. Reagents that are used as adsorbents for deep purification of substances are: A) silica, ceramics; B) coals, pumice, expanded clay; C) activated carbons, silica gels, zeolites; D) sand, quartzite, phosphorus sludge; E) aluminosilicates, diatomite. 41. Factors on which the quality of products depends: A) stability of technology, low level of development; B) level of development, instability of technology, certification of products; C) low level of development, metrological support of production, certification of products; D) non-certified products, instability of technology, low level of development; E) perfection and stability of technology, level of development, certification of products, metrological support of production. 42. The highest category of quality includes products that: A) meet internal standards; B) meet regulatory requirements; C) are competitive at the global market; D) have a high cost; E) have a low cost. 43. The highest category of quality includes products that: A) meet internal standards; B) meet regulatory requirements; C) provide a significant increase in labor productivity, saving materials, fuel and energy; D) have a high cost; E) have a low cost.
44. A device for determining the density of liquids is: A) hydrometer; B) viscometer; C) pressure gauge; D) thermometer; E) dilatometer. 45. Granulation is a process: A) dispersing the raw materials into small fractions; B) obtaining granular powder materials; C) obtaining pelletized material from a fine fraction of raw materials in drum furnaces; D) obtaining granules from a fine fraction of raw materials on sinter machines; E) obtaining from a powdered raw material granules of approximately the same size. 46. Raw material preparation methods are: A) screening, adsorption, air separation; B) screening, grinding, granulation; C) air separation, grinding, filtration; D) hydraulic classification, filtration; E) screening, hydraulic classification, air separation. 47. Purification of gases from dust and harmful substances is carried out to solve the problem: A) disposal of harmful emissions into the atmosphere; B) improving the environmental situation in the workplace; C) process improvements; D) improving the quality of chemical products; E) compliance of the content of dust and harmful substances with MPC standards. 48. Technological methods for cleaning gas from dust are: A) mechanical; B) neutralizing; C) distillation; D) gas conversion; E) thermochemical. 49. Technological methods for cleaning gas from dust are: A) electrical; B) neutralizing; C) magnetic; D) conversion; E) thermochemical.
50. The process of transition of a substance from a solid phase to a liquid is called: A) crystallization; B) precipitation; C) decomposition; D) dissolution; E) condensation. 51. The process of formation of a solid phase in solutions as a result of a chemical reaction is called: A) precipitation; B) dissolution; C) decomposition; D) crystallization; E) condensation. 52. The process of obtaining solid particles from dispersible in the form of droplets of solutions or suspensions by evaporation of moisture is called: A) electric drying; B) evaporation; C) spray drying; D) convective drying; E) evaporation. 53. The process of substance transition when heated from solid crystalline state to liquid state is called: A) dissolution; B) melting; C) decomposition; D) destruction; E) delamination. 54. The main factor determining the purity of the product: A) raw material composition; B) dispersion state; C) presence of impurities; D) crystal structure; E) moisture content. 55. A flotation enrichment product containing a useful component is called: A) concentrate; B) tail; C) fine matter; D) retour; E) waste.
56. Mechanical methods of enrichment of solid materials are: A) dispersion, gravitational separation; B) melting, screening; C) evaporation, condensation; D) flotation, sedimentation; E) crystallization, sedimentation. 57. Mechanical methods for the enrichment of solid materials are: A) evaporation, crystallization; B) melting; C) flotation; D) adsorption-desorption; E) absorption and desorption. 58. Fractions consisting of minerals not used in a given production are called empty (waste) rock, or: A) retour; B) concentrate; C) fines; D) tails; E) waste. 59. Method of raw material enrichment based on separation of magnetic rocks from non-magnetic rocks is: A) electromagnetic; B) screening; C) gravitational separation; D) separation; E) flotation. 60. The method of enrichment of raw materials, based on different sedimentation rates of particles of different sizes and densities in a liquid or gas stream, or on the action of centrifugal force: A) electromagnetic enrichment; B) gravitational dispersion, crushing; C) gravitational enrichment; D) electrostatic separation; E) flotation, deposition, sedimentation. 61. The method of enrichment of raw materials, based on various water wettability of the substances included in its composition, is called: A) separation; B) dispersion; C) electromagnetic enrichment; D) flotation; E) screening.
62. The method of enrichment of raw materials, due to different melting points of the substances included in its composition, is called: A) chemical; B) thermal; C) electrochemical; D) physicochemical; E) mechanical. 63. Methods of enrichment of sulfur pyrites are called: A) gravitational; B) flotation; C) sedimentation; D) electromagnetic; E) mechanical. 64. The process of separating the useful part of the raw material from waste rock in order to increase the concentration of the useful component is called: A) precipitation, filtration; B) melting, screening; C) enrichment; D) flotation, sedimentation; E) crystallization, sedimentation. 65. Kazakhstan deposits Ushtas, Koksu, Aksai belong to the following type of ores: A) phosphorites; B) bauxite; C) alumina; D) saltpeter; E) sylvinites. 66. The following mineral raw materials are extracted at Zhelyan field of Aktobe region: A) phosphorites; B) chromium ores; C) potassium salts; D) apatites; E) sulfide ores. 67. The following type of ore is classified as mineral deposit: A) iron-containing; B) vanadium-containing; C) sulfur-containing; D) magnetite; E) boron-containing.
68. Sulphate raw materials of Kazakhstan (mirabilite, tenartite, astrakhannite) are located in: A) the Aral Sea region; B) the Balkhash Basin; C) the Kyzylkum depression; D) Astrakhan plateau; E) Akchatau ridge. 69. Ores containing in their composition two or more valuable metal components are called: A) magnetic; B) monometallic; C) polymetallic; D) conjugate; E) alloyed. 70. Ores in which the content of non-sulfide minerals does not exceed 10% of their total mass are called: A) sulfide; B) sulfuric; C) non-sulfide; D) sulfate; E) sulfite. 71. The degree of enrichment of raw materials (Хо) is determined by the mass fractions of the useful component in the concentrate (μcc) and in the enriched raw materials (μcr) and is determined by the expression: A) Хо = μcc/μcr; B) Хо = μcr/μcc; C) Хо = μcc + μcr; D) Хо = μcc·μcr; E) Хо = μcc-μcr. 72. Ores, which contain 80-90% of non-ferrous metal sulfides and 10-20% of metal oxides, relate to: A) sulfide; B) combined; C) sulfate; D) mixed; E) oxide. 73. Ores, which contain more than 20% of the oxidized forms of metal, are called: A) oxidized; B) mixed; C) combined; D) acidic; E) alkaline.
74. Factor restraining the widespread use of pyrite cinders: A) the content of non-ferrous metals; B) sulfur content; C) selenium content; D) arsenic content; E) phosphorus content. 75. The principle of underground leaching of ores is based on: A) dissolving minerals in acids; B) dissolution of minerals in organic matter; C) dissolving minerals in water; D) precipitation of minerals in water; E) precipitation of minerals in acids and alkalis. 76. Underground leaching is used to isolate minerals: A) self-born; B) sulfides; C) sulfate; D) mixed; E) oxide. 77. Bacterial leaching is used to isolate minerals: A) sulfides; B) oxides; C) barites; D) apatites; E) phosphorites. 78. The most promising method of grinding ores is: A) planetary; B) self-grinding; C) shock resilient; D) ore-galic; E) ore-rotor. 79. The ore washing is carried out with the aim of: A) dissolution of minerals; B) relief from clay; C) ore swelling; D) improving the solubility of the base mineral; E) improving ore segregation. 80. Radiometric ore separation is based on: A) the combined interaction of minerals; B) the interaction of various types of radiation with minerals;
C) Coulomb repulsion of rock and mineral; D) the phenomenon of polarization of a liquid medium; E) the phenomenon of recombination. 81. The difference between chemical ore dressing and mechanical ore dressing: A) interaction with reagents to obtain a new substance; B) interaction of only dissolved components with flotation reagents; C) high speed of the process of extraction of the main mineral; D) lower capital costs per unit of output; E) carrying out the process only at high temperatures. 82. The phosphate fines formed during the extraction and preparation of raw materials from the Karatau basin are processed by the method of: A) firing; B) briquetting; C) flotation; D) agglomeration; E) segregation. 83. The widespread use of phosphorus slag for cement is limited to: A) phosphorus pentoxide; B) the content of REE; C) nickel and manganese content; D) sulfur content; E) chlorine content. 84. What is the purpose of classification of the material after crushing or grinding: A) separation of material into fractions; B) separation of minerals from each other and waste rock; C) separation of minerals from waste rock; D) separation of crystalline rock from amorphous rock; E) concentration of the main component of the rock. 85. Hydraulic or wet enrichment is based on the principle of: A) different segregation rates in the liquid of mineral grains and waste rock grains; B) different rates of dissolution in the liquid of ore material grains and waste rock; C) different flow rates of mineral grains and waste rock grains; D) different rates of deposition of ore mineral grains and waste rock in the liquid; E) different rates of enlargement of mineral grains and waste rock grains.
86. The main process for the enrichment of non-ferrous metal ores is: A) foam flotation; B) decrepitation; C) pneumatic enrichment; D) magnetic separation; E) gravitational enrichment. 87. The most important minerals containing aluminum are: A) bauxite, alunite, nepheline; B) apatite, phosphorite; C) borax, asharite; D) pyrites, sulfur; E) chalk, limestone. 88. The raw material for the production of boric acid and other boron compounds is: A) nepheline; B) dolomite; C) apatites; D) borax; E) barite. 89. The raw materials for alumina production are: A) bauxite; B) marble; C) apatites; D) limestone; E) chalk. 90. Potash ores are enriched by the following method: A) galurgy; B) decrepitation; C) magnetic separation; D) radiometric enrichment; E) electric enrichment. 91. From silvinite ore by galurgical method the following substances are obtained: A) calcium chloride; B) potassium chloride; C) magnesium chloride; D) barium chloride; E) copper chloride.
92. Processing of polymineral kainite-langbeinite ores by halurgical method gives: A) iron sulfate; B) barium sulfate; C) calcium sulfate; D) potassium sulfate; E) magnesium sulfate. 93. Chemical methods of enrichment include: A) liquid extraction; B) gravitational separation; C) electromagnetic separation; D) electrostatic separation; E) dispersion, flotation. 94. Salt, found in nature in the form of layers, rods and lenses, reaching a thickness of hundreds and thousands of meters, is called: A) stone; B) mountain; C) sedimentary; D) stalactite; E) stalagmite. 95. Natural raw materials containing calcium are called: A) limestone; B) sylvinite; C) tincal; D) pyrite; E) nepheline. 96. Mineral raw materials for sodium tetraborate or borax: A) asharite, hydroboracite; C) phosphorites, apatites; C) aluminosilicates; D) alumina, silica; E) sylvinite, nepheline. 97. The main sources of rare earth elements are minerals: A) asharite, feldspar, liparite; B) monazite, sylvinite, brown iron ore, sphene; C) bastnesitis, monazite, liparite, phosphorite, apatite; D) apatite, asharite, limonite, red iron ore; E) boracite, nepheline, chalcedony, phosphorite, bastnesitis. 98. Complex use of raw materials is: A) the use of renewable raw materials; B) expansion of volumes of extraction of raw materials;
C) the use of methods of chemical processing of raw materials; D) extraction of all useful components from raw materials; E) increasing the scale of production of raw materials. 99. The most universal way of enrichment of solid mineral raw materials: A) electromagnetic; B) gravitational; C) flotation; D) classification; E) adsorption. 100. Coefficient of energy use (η), is determined by the formula, where Wτ is an energy theoretically necessary, and Wps is an energy practically spent on the production of a unit of production: A) η = Wτ – Wps; B) η = Wτ/Wps; C) η = Wps/Wτ; D) η = Wτ·Wps; E) η = Wps -Wτ;.
2. MAIN CHEMICAL PRODUCTION 2.1. Sulfuric acid production Raw materials for the production of sulfuric acid. Production and purification of sulfur dioxide. Types of furnaces for roasting of sulfide ores and elemental sulfur. Use of waste sulfur dioxide of nonferrous metallurgy and thermal power plants, sulfur dioxide of oil refining Sulfur gas, as a raw material for sulfuric acid production, is obtainned by roasting sulfide ores, for example, in the chemical industry and non-ferrous metallurgy. In nature, sulfur is found mainly in three forms: sulfur compounds with metals (pyrite, copper pyrite, zinc blende, etc.); native sulfur mechanically mixed with other minerals; sulfates. Pure pyrite contains 53.5% S and 46.5% Fe. In sulfur pyrites, the sulfur content usually ranges from 35 to 50%, iron – from 30 to 40%. Pyrite firing in a stream of air is an irreversible non-catalytic heterogeneous process that proceeds with the release of heat through the stages of thermal dissociation of iron disulfide: 2FeS2 = 2FeS + S2 and oxidation dissociation of products: S2 +2O2 = 2SO2 4FeS2 +7O2 = 2Fe2O3 + 4SO2 The process is described by the general equation: 4FeS2 +11 O2 = 2Fe2O3 + 8SO2-ΔH where ΔН = 3,400 kJ.
The firing gas also contains a small amount of sulfur trioxide (SO3), since iron oxide at high temperatures is a catalyst for the oxidation of SO2 to SO3. Along with FeS2, sulfides of other metals contained in pyrites decompose. Their oxides, as well as quartz, some aluminosilicates together with iron oxide and undecomposed FeS2 form a cinder, which can contain from 0.5 to 3% sulfur. During burning of sulphurous iron, a layer of oxides forms on the grain surface, the thickness of which increases as the sulfur burns out of pyrite. The total rate of the process is determined by the rate of diffusion of gases in the pores of the oxide layer. Consequently, the combustion of pyrite proceeds in the intradiffusion region. The rate of the oxidative firing process is expressed by the general equation for heterogeneous processes: U = dm/dt = Km·F · ΔC where: Km is the mass transfer coefficient, F is the contact surface of the phases (catalyst), ΔC is the driving force of the process. Thus, the speed of the firing process depends on the temperature (through Km), the dispersion of the fired pyrite (through F, the concentration of iron disulfide in pyrite and the concentration of oxygen in the air (through ΔC). The combustion process can be accelerated by increasing Km, ΔC, and F. To increase the mass transfer coefficient, it is most effective to raise the temperature. However, at 850-1,000 °C the material in the furnace is sintered into large agglomerates; this sharply decreases the reaction surface. Therefore, the pyrite can be fired at a very specific temperature, depending, firstly, on the chemical composition and nature of pyrites, and secondly, on the design of the furnace in which the firing process is carried out. To increase the driving force of the ΔC process, it is necessary to increase the concentration of pyrite in pyrites and oxygen in the firing zone. Flotation enrichment is used to increase the pyrite concentration, and oxygen enriched air blasting can be used to increase the oxygen concentration. However, this method of increasing ΔC is quite expensive and therefore almost never used. To increase the oxygen concentration, an excess of air is used 1.5-2 times more often than stoichiometric method. 89
To reduce external diffusion inhibition, i.e. facilitate the supply of oxygen to the surface of the grain, apply vigorous mixing of the phases. The pyrite combustion process, as already mentioned, is limited by the internal diffusion of oxygen, i.e. supply of oxygen into the grain through its pores. Therefore, a more effective way to increase the burning speed of pyrite is to increase the contact surface of the phases due to fine grinding of the solid component. In practice, finely ground flotation pyrites with a particle size of 0.03 to 0.3 mm are used. Due to such a large difference in particle size, the rate of complete combustion of sulfur from pyrite for particles of different sizes differs tenfold. In a highly crushed pyrite on average up to 1.5% of unburned sulfur remains. Therefore, despite the fact that the stub contains up to 50% iron, it has not been used for a long time in the blast furnace process for the production of cast iron. Nowadays, the stub is agglomerated. In the process of agglomeration, sulfur burns out of it, and the stub is sintered into porous pieces-agglomerates. The stub prepared in this way is the raw material for the production of cast iron. The chemical composition of gas and cinder depends not only on the feedstock, but also on the design of the furnace in which pyrite is fired. The design of the furnace also affects the scheme for further purification and processing of sulfur dioxide. The most convenient apparatus for this reaction is a pyrite fluidized bed furnace (PFBF). The process temperature should be high enough to ensure a high reaction rate. At low temperatures (below 500 °C), the endothermic reaction of thermal decomposition of iron disulfide cannot occur. However, firing at very high temperatures can cause an undesirable physical process of sintering particles of burning material, leading to an increase in their size. The consequence of this may be an increase in the time of complete conversion of solid particles τn and a decrease in furnace productivity. The sintering temperature varies depending on the composition (grade) of pyrites from 800 to 900 °C. Carrying out the process in adiabatic mode would lead to heating to higher temperatures. Therefore, part of the heat of firing has to be removed inside the furnace. It is most convenient to do this in furnaces of the «fluidized 90
bed» type, since in the fluidized bed of solid material the heat transfer coefficient from the pyrite to the surface of the cooling elements is sufficiently high [≈1,000 kJ/(m2·h·K)] and cooling coils can be introduced into the «fluidized» layer. Several types of continuously operating furnaces are used for firing pyrite, in which the question of the nature of the movement of the solid phase is solved in different ways. In the old sulfuric acid plants mechanical (hearth) furnaces can be found. In such furnaces the crushed pyrite is on several hearths and burns as it is moved by strokes from one hearth to another. In furnaces firing pulverized particles of pyrites are burned during the fall in the hollow chamber. In cyclone furnaces pyrite is fed tangentially with hot air at high speed. Pyrite burns, rotating in the furnace with the air. The melted stub flows out through special holes. In the production of sulfuric acid, pyrite is mainly used for fluidized bed furnaces with a fluidized bed of solid material. In the fluidized bed, a high speed of diffusion and heat transfer processes is ensured (oxygen supply to the pyrite surface, removal of sulfur dioxide into the gas stream, removal of heat from the surface of the feed to the gas stream). The absence of inhibitory effect of mass and heat transfer allows pyrite firing in such furnaces at high speed. Fluidized Bed furnaces are characterized by maximum intensity in comparison with other designs used for firing pyrites. The disadvantages of the type of fluidized bed furnaces include high dust content of the calcining gas. In practice, during the firing of pyrites, the furnace gas contains 13-14% sulfur (IV) oxide, 2% oxygen and about 0.1% sulfur (VI) oxide. Since there must be an excess of oxygen in the furnace gas for the subsequent oxidation of sulfur (IV) oxide, its composition is adjusted by diluting with air to the content of sulfur oxide (IV) 7-9% and oxygen 11-9%. Cleaning of roasting (furnace) gas The firing gas must be cleaned of dust, sulfuric acid mist and substances that are catalytic poisons or of value as byproducts. The firing gas contains up to 300 g/m3 of dust, which at the contact stage clogs the equipment and reduces the activity of the catalyst, as well as sulfuric acid mist. 91
In addition, when firing pyrite simultaneously with the oxidation of iron, disulfide oxidizes sulfides of other metals contained in pyrite. In this case, arsenic and selenium form gaseous oxides As2O3 and SeO2, which pass into the firing gas and become catalytic poisons for vanadium contact masses. Dust and sulfuric acid mist are removed from the firing gas in the general gas cleaning process, which includes mechanical (coarse) and electrical (fine) cleaning operations. Mechanical cleaning of the gas is carried out by passing the gas through centrifugal dust collectors (cyclones) and fiber filters that reduce the dust content in the gas to 10-20 g/m3. Electric gas purification in electrofilters reduces the dust and mist content in the gas to 0.05-0.1 g/m3. After general cleaning, the firing gas obtained from pyrite is necessarily subjected to special cleaning to remove dust and mist residues and, mainly, arsenic and selenium compounds, which are disposed. The special gas purification includes operations of cooling it to a temperature below the melting points of arsenic oxide (315 ºC) and selenium (340 ºC) in towers irrigated successively with 50 % and 20 % sulfuric acid, removal of sulfuric acid mist in wet electrofilters and final drying of the gas in scrubbers irrigated with 95% sulfuric acid. From the special cleaning system, the roasting gas comes out at a temperature of 140-150 ºC. Selenium (IV) oxide extracted from the firing gas is reduced by sulfur (IV) oxide dissolved in sulfuric acid to metallic selenium, which is deposited in settling tanks:
SeO2 + 2SO2 + 2H2O = Se + 2H2SO4 A new progressive method of cleaning the roasting gas is the adsorption of impurities contained in it by solid absorbers, for example, silica gel or zeolites. With such dry cleaning, the firing gas is not cooled and enters the contact at a temperature of about 400 ºC, so that it does not require intensive additional heating. Sulphuric acid production. Physico-chemical bases and technological schemes of contact method of sulfuric acid production from sulfur dioxide and sulfur. Ways of intensification of sulfuric acid production 92
Sulfuric acid is a colorless viscous liquid, with a density of 1.83 g/ml (20º). The melting point of sulfuric acid is 10.3 ºC, the boiling point is 269.2 ºC. The chemical properties of sulfuric acid largely depend on its concentration. In laboratories and industry, diluted and concentrated sulfuric acid is used, although this division is conditional (a clear boundary between them cannot be drawn). Commodity types of sulfuric acid: – Tower H2SO4 (nitrous): C = 75-77%, Tcrystallization = -29.5 ºC – Contact H2SO4: C = 92.5%, Tcrystallization = -22.0 ºC and C = 98.3% – Concentrated H2SO4:C = 100% – Oleum H2SO4·nSO3: contains 18-20% free SO3, Tcrystallization = = +2 ºC. Sulfuric acid is transported in railway cars and tankers made of acid-resistant steel; stored in hermetically sealed containers made of polymer or stainless steel coated with an acid-resistant film. The main directions of use of sulfuric acid: production of mineral fertilizers, sulfates, synthetic fibers; ferrous and non-ferrous metallurgy; production of organic dyes, alcohols, acids, esters; food industry (molasses, glucose), emulsifier (thickener) E513; petrochemicals (mineral oils); explosives production; catalysis, etc. The raw materials for the production of sulfuric acid are: native sulfur, exhaust gases of thermal power plants, sulfates of iron, calcium, hydrogen sulfide, Cu2S, ZnS, PbS (non-ferrous metals), gypsum, FeS2 (pyrite) with a sulfur content of 54.3%. Pyrite mineral concentrates are obtained by enrichment of non-ferrous metal ores. Technology for production of sulfuric acid In industry for production of sulfuric acid, two main methods for the oxidation of SO2 are used: 1. contact – using solid catalysts; 2. nitrous – with nitrogen oxides. Contact method for production of sulfuric acid from pyrite FeS2 Before use, large pieces of pyrite are crushed in crushing machines. After grinding the pyrite, it is cleaned of impurities (gangue and earth) by flotation. For this, crushed pyrite is lowered into huge tanks with water, mixed, the waste rock floats up, then it is removed. 93
The first stage is burning of pyrite in a fluidized-bed kiln at t = 800 °C according to the reaction equation: 4FeS2 + 11O2 = 2Fe2O3 + 8SO2 + Q The crushed purified wet (after flotation) pyrite from above is poured into the kiln in a «boiling layer». Oxygen-enriched air is passed from below (counterflow principle) for better pyrite firing. The temperature in the kiln reaches 800 °C. Pyrite is heated to red and is in a «suspended state» because of the air blown from below in the form of a boiling liquid. The temperature in the furnace is maintained by the heat generated by the reaction. Excess heat is removed using a heat exchange system. The resulting iron oxide Fe2O3 (cinder) is not used in the production of sulfuric acid. But it is collected and sent to a metallurgical plant, where iron is obtained from iron oxide and its alloys with carbon – steel (2% carbon C in the alloy) and cast iron (4% carbon C in the alloy). In this way, the principle of chemical production is fulfilled – waste-free production. The furnace gas comes out of the furnace, the composition of which is: SO2, O2, water vapor (pyrite was wet!) and the smallest particles of cinder (iron oxide). Such a furnace gas must be cleaned of impurities of cinder solid particles and water vapor. Cleaning the furnace gas from solid particles of the cinder is carried out in two stages: – in a cyclone (centrifugal force is used, solid cinder particles hit the cyclone walls and crumble down); – in electrostatic precipitators (using electrostatic attraction, cinder particles stick to the electrified plates of the electrostatic precipitator, with sufficient accumulation under their own weight they crumble down). Concentrated sulfuric acid is used to remove water vapor in the furnace gas (drying the furnace gas), which is a very good desiccant because it absorbs water. The kiln gas is dried in a drying tower – kiln gas rises from bottom to top, and concentrated sulfuric acid flows from top to bottom. At the exit of the drying tower, the furnace gas does not contain any cinder particles or water vapor. The kiln gas is now a mixture of sulfur oxide SO2 and oxygen O2. 94
The second stage is the oxidation of SO2 to SO3 with oxygen in the contact apparatus in accordance with the reaction equation: 2SO2 + O2
2SO3 + Q
The optimum temperature for a direct reaction with the maximum formation of SO3 is a temperature of 400-500 °C. This is a fairly low temperature in chemical industries. In order to increase the reaction rate at such a low temperature, vanadium oxide (V2O5) is introduced into the reaction. A direct reaction proceeds with a decrease in gas volumes, so the process is carried out at elevated pressure. Before the mixture of SO2 and O2 enters the contact apparatus, it must be heated to a temperature of 400-500 °C. Heating of the mixture begins in the heat exchanger, which is installed in front of the contact apparatus. The mixture passes between the heat exchanger tubes and is heated. Inside the tubes, hot SO3 passes from the contact apparatus. Once in the contact apparatus, the mixture of SO2 and O2 continues to heat up to the desired temperature, passing between the tubes in the contact apparatus. The temperature in the contact apparatus is maintainned due to the released heat in the reaction of conversion of SO2 to SO3. As soon as the mixture of sulfur oxide and oxygen reaches the catalyst layers, the oxidation of SO2 to SO3 begins. The formed sulfur oxide SO3 leaves the contact apparatus and enters the absorption tower through a heat exchanger. The third stage is the absorption of SO3 by sulfuric acid in the absorption tower. If water is used to absorb sulfur oxide, sulfuric acid is formed in the form of a mist consisting of tiny droplets of sulfuric acid (sulfur oxide dissolves in water with the release of a large amount of heat, sulfuric acid is so hot that it boils and turns into steam). In order not to form a sulfuric acid mist, 98% concentrated sulfuric acid is used, while heating the liquid is insignificant and safe. Sulfur oxide dissolves very well in such an acid and forms oleum (H2SO4·nSO3). The reaction equation of this process: nSO3 + H2SO4 H2SO4·nSO3 95
The resulting oleum is poured into metal tanks and sent to a warehouse. Then the tanks are filled with oleum, the trains are formed and sent to the consumer. Contact sulfuric acid production from elemental sulfur The technological process for the production of sulfuric acid from elemental sulfur by the contact method differs from the production process from pyrites by a number of features. These include: – a special design of furnaces for producing furnace gas; – high content of sulfur oxide (IV) in the furnace gas; – lack of a stage of pre-treatment of furnace gas. Subsequent operations of contacting sulfur oxide (IV) on the physicochemical basis and hardware design do not differ from the pyrite-based process. The sulfuric acid production scheme from sulfur consists of: – air drying; – sulfur burning; – gas cooling; contacting; – absorption of sulfur oxide (IV) – formation of sulfuric acid. The «wet» catalysis There is also a method of producing sulfuric acid from hydrogen sulfide, called «wet» catalysis. It consists in that a mixture of sulfur (IV) oxide and water vapor produced by burning hydrogen sulfide in an air current is fed without separation to a contact where sulfur (IV) oxide is oxidized on a solid vanadium catalyst to sulfur (VI) oxide. The gas mixture is then cooled in a condenser, where the vapors of the sulfuric acid formed are converted into a liquid product. Thus, unlike the methods of sulfuric acid production from pyrite and sulfur, the wet catalysis process does not have a special stage of sulfur oxide (VI) absorption and the whole process involves only three consecutive stages: 1) hydrogen sulfide combustion: Н2S + 1.5О2 = SО2 + Н2О – ∆Н1, where ∆H1 = 519 kJ with the formation of a mixture of sulfur oxide (IV) and water vapor equimolecular composition (1:1). 96
2) oxidation of sulfur oxide (IV) to sulfur oxide (VI): SО2 + 0.5О2 = SО3 – ∆Н2, where ∆H2 = 96 kJ, while maintaining the equimolecularity of the composition of the mixture of sulfur oxide (IV) and water vapor (1:1). 3) vapor condensation and sulfuric acid formation: SО3 + Н2О = Н2SО4 – ∆Н3, where ∆H3 = 92 kJ. Thus, the wet catalysis process is described by the total equation: Н2S + 2О2 = Н2SО4 – ∆Н4, where ∆H4 = 707 kJ. The nitrous method for producing sulfuric acid was first used in the middle of the 18th century and until the 20s of the 20th century was carried out using the «chamber method» in lead chambers. Later it was carried out by the «tower method» in special towers. The acid obtained by the tower method (technical sulfuric acid), as a rule, contains 75-76% H2SO4 and is somewhat contaminated with various impurities. The main consumer of industrial acid is the mineral fertilizer industry. The towers are laid out of acid-resistant ceramic plates with an outer casing of sheet steel. Inside, they are loosely filled with an acid resistant ceramic nozzle. In the first stage of the tower method, the same for both methods, sulfur dioxide (SO2) is obtained. The feedstock can, in principle, be any substance containing sulfur: natural iron sulfides (primarily pyrite FeS2), as well as copper and nickel sulfides, sulfide polymetallic ores, gypsum CaSO4·2H2O and elemental sulfur. Sulfur-containing gases released during the processing and burning of fossil fuels (coal, oil) are also widely used. 97
The resulting SO2 is oxidized to H2SO4, and nitrogen oxides are used for this in the nitrous method. From this stage, both methods differ from each other. In a special oxidizing tower nitric oxide NO and NO2 are mixed with air in such a ratio that there is half of the available NO and NO2: 2NO + O2 → 2NO2 As a result, the gas mixture contains equal amounts of NO and NO2. It is fed to towers irrigated with 75% sulfuric acid; here the mixture of nitrogen oxides is absorbed with the formation of nitrosylsulfuric acid: NO + NO2 + 2H2SO4 → 2NO(HSO4) + H2O A solution of nitrosylsulfuric acid in sulfuric acid, called nitrosa, irrigates the towers, where SO2 flows in counterflow and water is added. As a result of hydrolysis of nitrosylsulfuric acid, nitric acid is formed: NO(HSO4) + H2O → H2SO4 + HNO2 Nitric acid then oxidizes SO2 to H2SO4: SO2 + 2HNO2 → H2SO4 + 2NO 75-76% sulfuric acid is accumulated in the lower part of the towers, naturally, in a larger amount than it was spent on the preparation of nitrosa (after all, «newborn» sulfuric acid is added). Nitric oxide NO returns again to oxidation. Since a certain amount of NO is lost with the exhaust gases, it is necessary to add HNO3 to the system, which serves as a source of nitrogen oxides. The disadvantage of the tower method is that the resulting sulfuric acid has a concentration of only 75-76% (at a higher concentration, the hydrolysis of nitrosylseric acid is bad). The concentration of sulphuric acid by evaporation presents an additional difficulty.
The advantage of this method is that the impurities contained in SO2 do not affect the process, so that the original SO2 is sufficiently cleaned of dust, i.e. mechanical contaminants. Naturally, tower sulfuric acid is not clean enough, which limits its use. TEST TASKS 1. Sulfur in nature is found in the form of: A) pyrite, barite, cinnabar; B) galena, asharite, oil; C) covelin, phosphorite, coal; D) arintitis, apatite, shale; E) antimonite, fluorspar. 2. Raw materials for sulfuric acid production: A) ferrous gases, coke oven gases, gypsum; B) enrichment tails, pyrite, phosphorite, barite; C) pyrite, gypsum, native sulfur, kaolin; D) bauxite, native sulphur, sylvinite, chrysocall; E) sulphuric pyrite ores, sulphide ore tailings; non-ferrous metals gases, petroleum sulphur, gypsum. 3. In Kazakhstan, the main raw material for the production of sulfuric acid is: A) sulfur pyrite; B) hydrogen sulfide; C) non-ferrous gases; D) monoclinic sulfur; E) native sulphur. 4. Sulfur-containing raw materials for the production of sulfuric acid is: A) bauxite; B) asharites; C) sylvinite; D) alunites; E) apatites. 5. Raw materials for sulfuric acid: A) trona, phosphorites, alunites; B) apatites, phosphorites; C) bauxite, apatite, gypsum; D) nepheline, phospholeum; E) gypsum, etching solutions, alunites.
6. Raw materials for the production of sulfuric acid: A) pyrites, apatites; B) sulfur, phosphorites; C) sulfur, pyrite; D) limestone, gypsum; E) trona, nepheline. 7. The following raw materials are used for the production of sulfuric acid:
A) sulphuric pyrite, sulphide ore enrichment tailings; non-ferrous metallurgy gases, gypsum; B) enrichment tailings, pyrite, alumina, barite, native sulfur; C) barite, pyrite, gypsum, native sulfur, kaolin; D) talc, native sulphur, silvinite; E) ferrous gases, coke oven gases, gypsum. 8. Secondary raw materials used to produce sulfuric acid: A) fuel oil; B) phosphogypsum; C) phosphoreum; D) stub; E) oil sludge. 9. In the production of sulfuric acid sulfurous gas is not subjected to further purification when used as a raw material: A) sulphur; B) pyrite; C) phosphogypsum; D) sulfides; E) gypsum. 10. The approximate concentration of sulfur in the gypsum: A) 15.6; B) 25.5; C) 32.5; D) 39.6; E) 18.6. 11. The main component of pyrite: A) FeS; B) Fe2O3; C) PbS; D) HgS; E) FeS2.
12. Natural raw materials, the inexhaustible reserves of which are in the Caspian, Aral and Balkhash reservoirs: A) potassium sulfate; B) potassium sulfide; C) sodium sulfate; D) sylvinite; E) sodium sulfite. 13. By dehydrating the natural raw materials of mirabilite, the following product is obtained: A) magnesium sulfate; B) potassium sulfide; C) calcium sulfite; D) sodium sulfate; E) zinc sulfide. 14. The raw materials for the production of sulfur dyes, thiosulfate and sodium hydrosulfide are: A) NaNO3; B) Na2SO3; C) Na3PO4; D) Na2S; E) Na2SO4. 15. The raw material for the production of sodium sulfate is: A) mirabilite; B) trona; C) silunite; D) apatite; E) nepheline. 16. In production of sodium sulfide as raw materials are used: A) sodium thiosulfate and coal; B) sodium sulfite and coke; C) sodium sulfide and anthracite; D) sodium sulfate and coal; E) sodium sulfite and coke. 17. Raw materials for the production of gas sulfur are: A) gases containing hydrogen sulfide; B) lump sulfur; C) gases containing carbon dioxide; D) gases containing sulfur dioxide; E) native sulfur.
18. The concentration of SO2 in the sulfur firing gas reaches: A) 50%; B) 19%; C) 21%; D) 75%; E) 93%. 19. Natural and process gases containing hydrogen sulfide include: A) converted gases, carbon dioxide, acetylene; B) flue gases, acetylene, ammonia; C) agglomeration gases, carbon monoxide; D) refinery waste gases, inert gases, ammonia; E) natural gas, coke oven gas, generator gas. 20. The reaction of producing sulfur dioxide from hydrogen sulfide: A) 2H2S + O2 = S2 + 2H2O; B) 2H2S + 4O2 = 2SO3 + 2H2O; C) 2H2S + SO2 = 3S + 2H2O; D) H2S + 2O2 = H2SO4; E) 2H2S + 3O2 = 2SO2 + 2H2O. 21. The composition of the gas obtained from hydrogen sulfide: A) SO2, SO3, N2, O2; B) O2, SO2, As2O3, NO2; C) H2O, SO2, N2, O2; D) SO3, SO2, N2, NO2; E) SeO2, SO3, N2. 22. To increase the degree of oxidation of SO2 to SO3 in the reaction SO2 + 0.5О2 = SO3, it is necessary to: A) reduce the concentration of SO3; B) increase the concentration of SO3; C) reduce the concentration of O2; D) increase the temperature of the process; E) lower the process pressure. 23. To increase the degree of SO3 absorption by sulfuric acid solutions, it is necessary to: A) reduce the concentration of SO3 in the gas; B) reduce pressure; C) increase the temperature; D) increase the concentration of SO3 in the gas; E) select the optimal concentration of sulfuric acid.
24. The oxidation process of sulfur dioxide in the presence of a catalyst is called: A) enrichment; B) firing; C) contacting; D) oxygenation; E) accession. 25. The method for purifying SO2-containing gases in the production of sulfuric acid is called: A) ammonia method; B) redox method; C) catalytic method; D) acid catalytic method; E) adsorption-desorption method. 26. The method for purifying SO2-containing gases in the production of sulfuric acid is: A) redox method; B) ozone-catalytic method; C) ammonia method; D) carbonate method; E) hydrochloride method. 27. Methods for extracting SO2 from various process gases are: A) absorption methods; B) neutralization methods; C) oxidative methods; D) electrochemical methods; E) restorative (recovery) methods. 28. The methods for extracting SO2 from various process gases are: A) hydrothermal; B) neutralizing; C) adsorption; D) restorative; E) electrothermal. 29. The methods for extracting SO2 from various process gases are: A) electrochemical; B) neutralizing; C) hydrothermal; D) catalytic; E) electrothermal.
30. Wet methods for the extraction of SO2 from exhaust gases, based on its absorption by aqueous solutions and suspensions, as well as some organic solvents, are called: A) adsorption; B) neutralizing; C) sorption; D) absorption; E) electrothermal. 31. The following reagents are used to extract SO2 from the exhaust gases by the adsorption method: A) Na2SO3, (NН4)2SO3, NaOН, Na2СО3, СаО, MgO, ZnO; B) K2SO3, NН4HSO3, KOН, K2СО3, СuО, MgO, PbO; C) CuS, NН4Cl, Ca(OН)2, CaСО3, СаCl2, MgCl2, ZnCl2; D) K2S, (NН4)2S, Ba(OН)2, BaСО3, СuО, Al2O3, UO3; E) CaSO4, (NН4)2SO4, LiOН, MgСО3, MgCl2, CuCl2, BaCl2. 32. Methods based on the extraction of SO2 from exhaust gases using solid sorbents are called: A) electrochemical; B) neutralizing; C) hydrothermal; D) adsorption; E) electrothermal. 33. The adsorption method for the extraction of SO2 from exhaust gases is carried out on the following adsorbents: A) bentonite, СаCl2, MgCl2, ZnCl2, CuCl2, BaCl2; B) alumina, CaСО3, MgСО3; C) alumina, MgO, ВaСО3, K2СО3; D) molecular sieves, СuSO4, Al2O3, (NН4)2SO3, K2СО3; E) activated carbon, MnO2, Na2СО3. 34. As catalysts for the extraction of SO2 from exhaust gases are used: A) Fe2О3, bentonite, СаCl2; B) MgO, alumina, H2SO4; C) СаО, Al2O3; D) MnO2, activated carbon, H2S2O8; E) ZnO, expanded clay, H2S2O3. 35. The following methods are used to reduce SO2 emissions from exhaust gases in the production of sulfuric acid: A) double contacting; B) adsorption; C) thermal neutralization; D) electrochemical; E) electrothermal.
36. The main method of purification of exhaust gases from SO2, which has found industrial application, is: A) carbonate method; B) calcareous method; C) sulfate method; D) sulfite method; E) ammonia method. 37. The following formula corresponds to an aqueous solution of sulfuric acid:
A) 2SO3·3.5Н2О; B) SO3·Н2О; C) 0.5SO3·2Н2О; D) SO3·2.5Н2О; E) SO3·3.5Н2О. 38. The main stages of obtaining sulfuric acid by contact method from pyrites are: A) firing of secondary raw materials → production of SO2 → purification and drying of gas → absorption of SO2 → evaporation and concentration of sulfuric acid; B) production of SO2 → gas drying → oxidation of SO2 to SO3 → absorption of SO3 → evaporation and concentration of sulfuric acid; C) firing of raw materials → production of SO2 → purification and drying of sulfur dioxide → absorption of SO2 to sulfur dioxide; D) production of SO2 → purification of gas from impurities → oxidation of SO2 to SO3 (on the catalyst) → absorption of SO3; E) firing of mineral raw materials → production of SO2 → oxidation of SO2 to SO3 → absorption of SO3 → evaporation and concentration → cooling of the product. 39. The main components of sulphurous gas of the pyrite firing process are:
A) H2, SO2, N2, O2, HCl, SiF4, NO; B) SO3, N2, NO2, NO, N2O4, HCl, Н2О; C) SO2, As2O3, SO3, HF, SiF4, SeO2, TeO2; D) O2, SeO2, NO2, N2O3, SiF4, NO; E) SO3, SiF4, NO, N2, SiF4, NO2. 40. The catalyst used in the reaction SO2 + 1/2O2 = SO3 + Q is: A) vanadium catalyst; B) ruthenium catalyst; C) rhodium catalyst; D) platinum-rhodium catalyst; E) iron-chromium catalyst.
41. The general reaction for firing sulfur pyrite is described by the equation:
A) 4FeS+ 7O2 = 4SO2 + 2Fe2O3; B) 2FeS2 + 3O2 = 2FeS + 2SO3; C) FeS2 → FeS + S; D) 4FeS2 + 11O2 = 8SO2 + 2Fe2O3; E) 3FeS + 5O2 = 3SO2 + Fe3O4. 42. Pyrite firing is carried out at a temperature of ºC: A) 350-420; B) 1,000-1,020; C) 300-450; D) 750-850; E) 1,300-1,400. 43. Sulfuric acid concentration at the inlet and outlet of the 1st drying tower, %: A) 98.3-98.7; B) 93-92.5; C) 25-27; D) 95-98; E) 37-38.5. 44. The concentration of sulphuric acid, irrigating the 2nd drying tower, %: A) 93-92.5; B) 95; C) 75-76; D) 25; E) 25-27. 45. Causes of pyrite sintering in the kiln: A) high content of SO3 in the gas; B) no mixing; C) formation of fusible mixtures; D) lowering the temperature; E) high SO2 content in the gas. 46. The composition of the cinder in the sulfuric acid production includes the following components: A) ZnS, MgO, CaS, Na2S; B) Fe2O3, MgSO4, Na2SiO3; C) Fe2O3, FeO, FeS, CuS, ZnS, CaSO4; D) CaO, MgS, PbS, K2S; E) FeO, CaSO4, MgSO4, Al2O3.
47. The waste of sulfuric acid production, which is a valuable raw material for the production of pig iron, is: A) gypsum; B) cinder; C) slag; D) sludge; E) sulfates and sulfites. 48. The method of obtaining technical (tower, 75% -77%) sulfuric acid is: A) sulfate; B) contact; C) sulfide; D) catalytic; E) nitrous. 49. Technical sulfuric acid according to SS 2184-77 corresponds to the following concentration, %: A) 75.0 – 77.0; B) 90.0 – 91.1; C) 85.5 – 90.0; D) 92.5 – 94.0; E) 66.0 – 78.5. 50. The reasons for formation of acid mist in the production of sulfuric acid: A) excess moisture in the contact reactor; B) overheating in the apparatus of a monohydrate absorber; C) low atmospheric pressure in the oleum absorber; D) high temperature in the drying tower; E) mixing of exhaust gases with atmospheric moisture. 51. In the production of sulfuric acid by the nitrous method, the following substances are used: A) nitrogen oxides; B) sodium sulfate; C) carbon monoxide; D) carbon dioxide; E) ammonia. 52. In the production of sulfuric acid by the nitrous method, nitrosa is understood as: A) a solution of N2O3 in H2SO3; C) a mixture of NO and N2O3; C) a solution of NO2 in H2SO3; D) a solution of N2O3 in H2SO4; E) a mixture of N2O3 and NO2.
53. Sulfuric acid (100% H2SO4), which is a compound of one molecule of sulfuric anhydride with one molecule of water, is called: A) crystalline hydrate; B) hemihydrate; C) monohydrate; D) an aqueous solution; E) fuming acid. 54. Sulfuric acid containing a mixture of 1 mole of SO3 and more than 1 mole of water is called: A) fuming acid; B) monohydrate; C) hemihydrate; D) crystalline hydrate; E) an aqueous solution. 55. Sulfuric acid containing a mixture of 1 mole of water and more than 1 mole of SO3 is called: A) oleum; B) monohydrate; C) phospholeum; D) hemihydrate; E) crystalline hydrate. 56. Fuming sulfuric acid is called: A) crystalline hydrate; B) monohydrate; C) phospholeum; D) hemihydrate; E) oleum. 57. In the monohydrate absorber in the production of sulfuric acid by contact method is obtained: A) oleum; B) monohydrate; C) phospholeum; D) semihydrate; E) crystallohydrate. 58. In the production of sulfuric acid by contact method, a monohydrate absorber is irrigated with acid with a concentration of: A) 96.5%; B) 99.9%; C) 100.0%; D) 98.3%; E) 40.0%.
59. In the production of contact sulfuric acid, the following types of filters are used for cleaning from spray and fog: A) mesh; B) sleeve; C) pressing; D) teflon; E) porolithic. 60. In the production of contact sulfuric acid, which catalyst is used: A) WS2; B) MoS2; C) V2O5; D) NiO; E) WO3. 61. In sulfuric acid production, contact poisons poisoning a vanadium catalyst are: A) S, H2S; B) Se, Te; C) NH3, HCl; D) As, F; E) NH3, H2S. 62. The role of the catalyst in the production of sulfuric acid is: A) maintaining the process temperature; B) reduction in the concentration of sulfur dioxide; C) acceleration of the oxidation of sulfur dioxide; D) stabilization of pressure in the reactor; E) an increase in the activation energy. 63. The processing method of sulfur dioxide by sulfuric acid, in which oxides of nitrogen (nitrosa) are dissolved, is called: A) ammonia; B) sulfate; C) sulfite; D) nitrous; E) sulfide. 64. Oleum composition corresponds to the formula: A) SO3·1.5Н2О; B) SO3·3.5Н2О; C) SO3·Н2О; D) 0.5SO3·2.5Н2О; E) 1.5SO3·Н2О.
65. In the production of sulfuric acid by the contact method, the following substance is obtained as a product: A) cinder; B) sludge; C) oleum; D) trona; E) potash. 66. In the production of sulfuric acid by contact method, along with the main product, the following product is obtained: A) oleum; B) monohydrate; C) phosphoreum; D) semihydrate; E) crystallohydrate. 67. The concentration of oleum at the inlet and outlet of the oleum absorber is equal to: A) 95 – 95.5% Н2SO4; B) 20 – 25% SO3 free; C) 12 – 16% SO3 free; D) 18.5 – 205% SO3 free; E) 98.3 – 98.8% Н2SO4. 68. Concentration of SO3 (free) in production oleum, %: A) not less than 18.5; B) not more than 16.5; C) less than 15.0; D) more than 13.8; E) more than 10.9. 69. By what method can oleum be obtained: A) contact; B) nitrous; C) sulfide; D) catalytic; E) sulfate. 70. In the production of contact sulfuric acid oleum absorber is irrigated with oleum with a concentration of free SO3, %: A) 40; B) 25-40; C) 19-24; D) 10-14; E) 12-15.
71. A valuable product contained in the firing gas of sulfuric acid production, used in photography, television, glass industry is: A) antimony; B) arsenic; C) tellurium; D) fluorine; E) selenium. 72. Before feeding the roasting gas for sulfuric acid production to the contact apparatus, it is necessary to remove from it the impurities that are poisons for the catalyst: A) lead; B) selenium, tellurium; C) lead, zinc; D) arsenic, fluorine; E) antimony, arsenic. 73. Before supplying the roasting gas for sulfuric acid production to the contact apparatus it is necessary to extract valuable impurities from it: A) lead, zinc; B) arsenic, fluorine; C) selenium, tellurium; D) chromium, manganese; E) gold, silver. 74. Scope of selenium usage: A) light industry; B) the textile industry; C) electronic industry; D) pharmacy; E) metallurgy. 75. The process of selenium extraction in the production of sulfuric acid consists of three stages: A) firing of raw materials → production of SO2 → purification and drying of sulfur dioxide → absorption of SO2 to sulfur dioxide; B) absorption of SO2 from the burning gas by sulfuric acid → reduction of SO2 to elemental sulfur → emission of particles of elemental sulfur from sulfuric acid; C) absorption of SеO2 from the calcining gas by sulfuric acid → reduction of SеO2 to elemental selenium → separation of particles of elemental selenium from sulfuric acid; D) firing of secondary raw materials → production of SO2 → purification and drying of gas → absorption of SO2 → evaporation and concentration of sulfuric acid; E) firing of mineral raw materials → production of SO2 → oxidation of SO2 to SO3 → absorption of SO3 → evaporation and concentration → cooling of the product.
76. The content of selenium in poor selenium sludge of sulfuric acid production is: A) up to 5%; B) up to 15%; C) up to 25%; D) up to 40%; E) up to 35%. 77. At what stage are the off-gases produced in the production of H2SO4 obtained by the contact method: A) absorption of SO3; B) dry gas cleaning; C) firing of pyrite; D) cooling the acid; E) oxidation of SO2 to SO3. 78. Solid waste product of sulfuric acid obtained by the contact method is: A) ferrophosphorus; B) gypsum; C) cinder; D) sludge; E) phosphogypsum. 79. The stage in the production of sulfuric acid, accompanied by the formation of large-tonnage waste – cinder is: A) absorption of gases and dust; B) drying of sulfur dioxide; C) absorption of sulfuric anhydride; D) firing of pyrite; E) oxidation of SO2 to SO3. 80. Stage in the production of sulfuric acid, accompanied by the formation of poor and rich selenium sludge: A) firing of pyrite; B) dry gas cleaning; C) wet gas cleaning; D) cooling the acid; E) oxidation of SO2 to SO3. 81. When cleaning the roasting gas from the spray and mist of sulfuric acid on wet electrofilters, selenium sludge containing selenium is released, %: A) up to 50; B) up to 15; C) up to 25; D) up to 35; E) up to 45.
82. To which compound does selenium go when firing pyrites: A) SeO2; B) SeCl4; C) Н2SеO3; D) Н2SеO4; E) Н2Se. 83. Neutralization of wastewater in sulfuric acid production is carried out by:
A) persulphuric acid; B) potash, salt; C) alumina, coal; D) lime, soda; E) chalk. 84. Neutralization wastewater treatment using lime in sulfuric acid production proceeds according to the reaction:
А) Na2СО3 + H2SO4 = Nа2SO4 + Н2О + CO; В) NaCl + 2C + H2SO4 = 2HCl + Na2S + 2CO2; С) СаО + Н2О + H2SO4 = СаSO4 + 2Н2О; D) K2СО3 + H2SO4 = K2SO4 + Н2О + CO; E) 2NH3 + H2SO4 = (NH4)2SO4. 85. For preparation of 100 ml of 1 M solution of H2SO4 acid (g) is required: A) 9.8; B) 980; C) 0.098; D) 4.9; E) 0.98. 86. Calculate the amount of sulfur pyrite (kg) required to produce 100m3 of roasting gas with a SO2 concentration of 15% by reaction: 4FeS2 + 11O2 = 2Fe2O3 + 8SO2: A) 75.1; B) 65.5; C) 40.1; D) 120.3; E) 145.5. 87. Calculate the amount of pyrite (kg) containing 45% S needed to produce 1 ton of H2SO4: A) 150.3; B) 126.5;
C) 246.6; D) 518.3; E) 725.6. 88. The concentration of sulfuric acid obtained by double adsorption and double contacting from pyrite firing gas is equal to: A) 96%; B) 75%; C) 98.3 %; D) 73%; E) 92.5%. 89. The process of firing sulfur pyrite is carried out in accordance with the following technological scheme: A) complex cyclical; B) cyclical; C) open circuit; D) bypass; E) parallel. 90. Sulfuric acid production is carried out in accordance with the following scheme: A) parallel; B) cyclical; C) open; D) bypass; E) combined. 91. Calculate the expenditure coefficient of sulfur pyrite by the reaction: 4FeS2+11O2 = 2Fe2O3+8SO2, – if it contains 35% sulfur: A) 1.5340; B) 1.6672; C) 2.5158; D) 1.4286; E) 1.2324. 92. The optimal SO2 content in the firing gas supplied to contact oxidation is: A) 3%; B) 15%; C) 20%; D) 12%; E) 7%. 93. The purpose of the drying tower in the production of sulfuric acid: A) purification from sulfuric acid fog; B) dust removal;
C) purification from catalytic poisons; D) acid condensation; E) gas heating. 94. The purpose of the wash towers in the production of sulfuric acid: A) gas cooling; B) purification from sulfuric acid fog; C) dust removal; D) acid condensation; E) purification from catalytic poisons. 95. The most productive furnace for burning sulfur: A) rotating; B) fluidized bed; C) shelf; D) pulverized firing; E) cyclone. 96. The concentration of tower sulfuric acid is equal to: A) 99.9%; B) 75-77%; C) 96-97%; D) 93%; E) 92.5%. 97. Oleum concentration: A) 99.5%; B) 92.5%; C) up to 20% free SO3; D) 93%; E) 75%. 98. After firing pyrites, the following devices are used for dry gas purifycation: A) wet electrostatic precipitators; B) wash towers; C) drying towers; D) a cyclone; E) wet electrostatic precipitators. 99. After firing pyrites for dry gas purification, the following devices are used: A) dry electrostatic precipitator; B) wash towers; C) drying towers; D) wet electrostatic precipitator; E) solid adsorbent.
100. The optimal firing temperature of sulfur pyrite in sulfuric acid production: A) 450 ºC; B) 500 ºC; C) 800 ºC; D) 650 °C; E) 440 ºC.
2.2. Technology of nitrogen fixation Atmospheric nitrogen binding methods (arc, cyanamide, ammonia). Methods of producing nitrogen-hydrogen mixture (separation of gases by the method of deep cooling, conversion of generator and natural gas). Technology of purification of gases. The main methods for fixing atmospheric nitrogen: – arc; – cyanamide; – ammonia; – variant of the ammonia method. The arc method was developed in the late XVIII and early XX centuries. Nitrogen was bound from atmospheric air by oxidation with oxygen at an arc temperature of 3,000 – 4,000 ºС and an energy consumption per 1 ton of bound nitrogen of 60,000 kW · h: N2 +O2 ↔ 2NO-181.2 kJ NO +1/2O2 → NO2 +Q 3NO2 +H2O → HNO3 +NO Today, instead of the electric arc, the plasma method is used, which is less energy-consuming. The cyanamide method was developed in the twentieth century in the production of CaСN2 fertilizer:
The energy consumption per 1 ton of bound nitrogen by the cyanamide method is 12,000 kW · h. The ammonia method was developed in Germany and Russia in the XIX-XX centuries. The basic reaction equation is: N2 + 3H2 ↔ 2NH3 + 112 kJ The energy consumption per 1 ton of bound nitrogen by the ammonia method is 5,000 kW · h with a process capacity of 100,000300,000 tons/year. The ammonia method is the most energy-efficient process. A variant of the ammonia method is to obtain NH3 and Al2O3 from bauxite through Al nitride (early 20th century). Methods for producing a nitrogen-hydrogen mixture (NHM) Methods for producing nitrogen: 1) the physical separation of air into nitrogen and oxygen; 2) the joint production of nitrogen and hydrogen by binding O2 to CO2 and its separation. Hydrogen production. The main industrial methods for synthesis of hydrogen (carbon and carbon monoxide conversion, water electrolysis and coke oven gas processing). Synthesis of ammonia. Physico-chemical basis of the process of ammonia synthesis (composition of the nitrogen-hydrogen mixture, catalysts, pressure, temperature). The choice of optimal synthesis conditions. Technological (circulating) ammonia production scheme Sources of hydrogen: – natural gas; – methane and its homologs; – water, semi-water, coke oven gases; – water. The liquefaction of air is carried out by throttling, followed by distillation. Hydrogen production by methane conversion (co-production of nitrogen and hydrogen by binding O2 to CO2 and separating it): a) methane conversion by water vapor: 117
CH4 + H2O ↔ 3H2 + CO-206 kJ b) conversion of methane by oxygen: CH4 + 1/2 O2 ↔ 2H2 + CO + 35 kJ c) CO steam reforming: CO + H2O ↔ H2 + CO2 + 41 kJ The total conversion process of CH4 with water vapor: CH4 + 2H2O ↔ CO2 + 4H2-165 kJ Methods of separation of CO2, CO, H2S, O2, Ar, CH4 from nitric mixture: Wet method: a) chemisorption by alkaline solutions: CO2 and H2S (ethanolmine, diethanolamine, K2CO3 solution); CO (copper acetate ammonia solution); b) hydrogenation:
CO 3H 2 CH 4 H 2O Q CO 2 4H 2 CH 4 2H 2 O Q
O 2 2H 2 2H 2O Q The dry method – adsorption by solid adsorbents The process is carried out at T = 420-500 ºС, P = 32 MPa, on the catalysts – Feporous /Al2 О3 , K₂ O, CaO, SiO₂ , with a ratio of N2:H2 = 1:3 and the reverse process speed V = 15,000-25,000 h-1. The productivity of the process is P = 20-40 tons per day with 1 m3 of catalyst, the degree of ammonia conversion is XNH3 = 15-20%. c) washing with liquid nitrogen at -190 ºС (СО, CH₄, Ar). Industrial methods of ammonia production depending on the pressure are divided into: 118
– under low pressure up to 10 (10-15) MPa; – under middle pressure 20-30 (25-60) MPa; – high pressure 75-100 (60-100) MPa. Physical and chemical bases of ammonia synthesis process The exothermic, reversible; ratio of N2:H2 = 1:3; because the process is by reducing the amount necessary to reduce T and increase R (much lower T is disadvantageous because it decreases the speed of the process and the performance of Toptimal = 400-500 °C). The maximum conversion reaches 97% at T = 400 °C and at P > 350 MPa. Lowering the pressure increases the equilibrium yield of ammonia, so application of a very high pressure is disadvantageous (Poptim = 32 MPa). Industrial ammonia synthesis catalyst-GIAP: |Fe|
+ |Al O + K O + CaO + siO |
Also as catalysts of process are applied: Mn, Rh, W, Re, U, Os, Pt. The main areas of ammonia use: production of nitric acid, mineral fertilizers (urea, ammophos), nitrates, sulfates, ammonium carbonates, herbicides, hydrazine, polyamides, polyurethanes, polyacrylonitriles, urea-aldehyde polymers, urotropin, etc. Nitric acid production. General scheme of nitric acid production. Physico-chemical basis of the synthesis of nitric acid from ammonia. Oxidation of ammonia and nitrogen oxides. Chemisorption of nitrogen oxides. Production of dilute nitric acid. Production of concentrated nitric acid. Methods of nitric acid concentration. Nitric acid is one of the most important mineral acids. In terms of production, it ranks second after sulfuric acid. It is used for the production of nitrogen and complex mineral fertilizers (up to 40%), synthetic dyes, explosives, nitro-varnishes, plastics, medicinal substances; for passivation and protection of iron from corrosion, etc. In laboratory practice, nitric acid with a concentration of 65% is usually used. Two types of HNO3 are used in industry: diluted (50-60%) and concentrated (96-98%). It has Tmelting = – 41.6 ºC, Tboiling point = – 82.6 ºC. Its density is 1.552 g/cm3. It mixes with water in any proportions, forming an azeotrope (68.4% by weight of HNO3 Tboil = 121.9 ºC).
The following equilibrium processes occur in anhydrous nitric acid:
3HNO3 H 3O NO 3- H 3O 2NO3 NO 2 Pure nitric acid is self-ionized, and the molar concentration of each type of particle is 0.51 mol/L at -10 ºC:
2HNO3 NO 2 NO3- H 2 O In the solid state, the acid molecule is nitronium hydroxide:
Na OH 2
History of nitric acid production The method of obtaining nitric acid by heating a mixture of saltpetre with iron vitriol or alum was first described in the eighth century. Later it was found that nitric acid is also formed by the action of concentrated sulfuric acid on nitrate, this method was used until the early 20th century:
NaNO3 H 2SO 4 NaHSO4 HNO3 In 1839, the French scientist Kulman obtained nitrogen oxides by the contact oxidation of ammonia on sponge platinum. Upon cooling the formed nitrogen oxides, nitrous and nitric acids were obtained from them. In modern industries, the method of synthesis of nitric acid from nitrogen oxides obtained by the oxidation of ammonia on platinum is used. In 1913, the industrial synthesis of ammonia from elementary substances was mastered, it quickly became widespread. Soon, a method for production of nitric acid from ammonia was developed. The priority in the development of the method for production of nitric acid from nitrogen oxides obtained by oxidation of ammonia on platinum belongs to V. Ostwald and II. Andreev, who solved this problem independently of each other. The first plant for the production of nitric acid, according to a scheme operating at atmospheric 120
pressure with a capacity of 8,000 t/year, was built in 1916 in the city of Yuzovka. The method was based on the oxidation of ammonia obtained from coke oven gas, proposed by Russian scientist I.I. Andreev. Platinum nets were used as process catalysts. In 1906, a method was proposed for fixing atmospheric nitrogen in an electric arc flame. The method did not require the use of artificial raw materials and the complex design of the process, but consumed a large amount of electricity, which was not profitable from the economic point of view. The arc method of nitrogen bonding over time has been completely superseded by the contact oxidetion of synthetic ammonia. Thus, in a relatively short period of time, two methods for producing nitric acid were developed: – the arc method of direct oxidation of atmospheric nitrogen to nitric oxide and further processing into nitric acid; – a method of contact oxidation of ammonia, in which nitrogen is first bound to hydrogen, and then the resulting ammonia is sequentially oxidized to nitric oxide and nitrogen dioxide and absorbed by water to form nitric acid. Currently, a method for producing nitric acid by the electric arc method is being studied in detail. It is likely that in the future, due to widespread electrification, the temporarily forgotten method of producing nitric acid in electric furnaces of a special design will be used (1907-1909 A.I. Gorbov and V.F. Mitkevich). The raw materials for the nitric acid production are ammonia, air and water. Synthetic ammonia is more or less contaminated with impurities. Such impurities are catalyst dust, lubricating oil (when compressed by a piston compressor). To obtain pure gaseous ammonia, evaporation stations and distillation compartments of liquid ammonia are used. Atmospheric air used in the production of nitric acid is taken in or near the plant. This air is contaminated with gaseous impurities and dust. Therefore, it is thoroughly cleaned to prevent poisoning of the ammonia oxidation catalyst. Air purification is carried out, as a rule, in a scrubber, and then in a two-stage filter. Water used for technological needs is subjected to special preparation: sedimentation of mechanical impurities, filtration and chemical purification from salts dissolved in it. Pure steam condensate is required to produce reactive nitric acid. 121
There are productions of dilute and concentrated nitric acid. Dilute acid is mainly used for the production of nitrogen-containing mineral fertilizers. Concentrated nitric acid is used for the manufacture of explosives, dyes, plastics, nitrovarnishes, films, and other important products. Nitric acid is produced from ammonia. The process for the production of dilute nitric acid consists of three stages: 1) the conversion of ammonia in order to obtain nitric oxide:
4NH3 5O2 4NO 6H2 O Q; 2) the oxidation of nitric oxide to nitrogen dioxide:
2NO O 2 2NO 2 Q; 3) absorption of nitrogen oxides by water:
4NO2 O 2 2H2 O 4HNO3 Q. The total reaction of nitric acid formation is expressed by the equation:
NH3 2O2 HNO3 H 2O The process catalysts The vast majority of metals and their compounds are active in the ammonia oxidation reaction, but very few of them provide a high NO yield (above 90%). So, in 1902 W. Ostwald showed the superiority of platinum in the activity and selectivity over all other types of catalysts. With high activity and selectivity, platinum has a low ignition temperature (about 200 °C), and good plasticity. The disadvantage of platinum is its rapid destruction at high temperatures under the influence of high-speed flows of reagents and catalyst poisons. This leads to the loss of an expensive catalyst and a decrease in the yield of NO, which was the reason for the search for catalytically active alloys of platinum with other metals. The conducted industrial tests showed stable operation of catalysts made of platinum with palladium additives, as well as from the triple alloy Pt-Rh-Pd; this was the basis for their industrial implementation. As catalysts, platinoid catalysts (Pt, Pt-Rh and Pt-Pd-Rhalloys with a platinum content of 81– 92%) are used. 122
The catalysts used for contact oxidation of NH3 are made in the form of nets. This form of catalyst is convenient in operation, associated with minimal metal costs, allows you to use the most convinient type of contact apparatus in operation. In Russia, wire meshes with a diameter of 0.09 mm (SS 3193 – 74) are used, the cell side size is 0.22 mm, the number of cells per 1 cm of length is 32, per 1 cm2 – 1,024. Platinum-rhodium (GIAP-1) and platinum rhodiumpalladium (alloy No.5) catalysts are very sensitive to a number of impurities that are contained in ammonia and air. Such impurities include: – phosphorus and arsenic hydrides, – fluorine and its compounds, – dichloroethane, – mineral oils, – acetylene, – sulfur dioxide, – hydrogen sulfide, etc. The most powerful catalyst poisons are sulfur and fluorine compounds. Impurities significantly reduce selectivity of the catalyst, contribute to an increase in the loss of platinum. To maintain a stable degree of ammonia conversion, thorough purification of the ammonia-air mixture from mechanical impurities, especially from iron oxides and dust of an iron ammonia synthesis catalyst, is necessary. Dust and iron oxides, getting on the catalyst grids, clog them, reducing the contact surface of gases with the surface of the catalyst, and reduce the degree of oxidation of ammonia. In the process of ammonia oxidation reaction, the surface of platinoid meshes is strongly loosened, elastic filaments of the meshes become brittle. In this case, the surface of the grid increases by about 30 times. First, this leads to an increase in the catalytic activity of the catalyst, and then to the destruction of the grids. In practice, it has been established that catalyst meshes for work under pressure of 0.73 MPa withstand service life from 8 to 9 months. The effect of the catalyst One of the problems of increasing the yield of nitric acid is the creation of such a catalyst that would act selectively on the reaction of contact oxidation of ammonia to nitric oxide (II), with little effect 123
on side reactions. The main reaction proceeds very quickly in the external diffusion region, and the process is limited by the diffusion of oxygen to the catalyst surface. This causes an increased concentration of ammonia on the catalyst surface compared to oxygen and an increase in the specific gravity of the side reactions of incomplete oxidation with the formation of nitrogen and nitrous oxide. Therefore, a significant excess of oxygen at the surface is needed to displace ammonia from it. Then its oxidation to NO will be deeper. Effect of O2:NH3 flow ratio on NO yield With the O2:NH3 ratio of more than 1.8, the NO selectivity reaches a constant maximum value close to 100% and then practically does not change, which corresponds to the ammonia content in the ammonia-air mixture of 9.5-10.5 (vol.%). It should be borne in mind that at ordinary temperature the mixture of ammonia with air explodes in the range 16-27 (vol. %), and with increasing temperature and pressure the explosive limit expands. The effect of temperature Temperature has a slightly accelerating effect on the process, since the reaction is limited by external diffusion. At the same time, the NO yield varies with extreme temperature with a maximum in the range 900–920 ºС due to the progression in this region of the reaction, which proceeds with the formation of nitrogen and also thermal dissociation of ammonia and other side reactions:
4NH3 3O2 2N2 6H2O Q;
2NH3 N2 3H2 . In addition, with increasing temperature, the entrainment of the catalyst in the form of volatile oxide – PtO2 increases. To capture Pt, a CaO-based absorber is placed under the nets, which traps more than 50% of platinum. Taking into account the action of these opposite factors leads to the choice of the optimal temperature of 830-930 ºС (depending on the combination of other parameters). The optimum temperature position depends on pressure. With increasing 124
pressure, it shifts to the region of higher temperatures, although the value of the maximum yield decreases due to an increase in the specific gravity of the reaction with increasing pressure:
4NH3 6NO 5N2 6H2O Q The effect of pressure Pressure is a factor in accelerating the process, as it is the driving force of external diffusion. At the same time, with an increase in pressure, a decrease in the yield of nitric oxide (II) is observed. Therefore, the pressure is the optimal value combining the mutually opposite requirements of increasing productivity and reducing the dimensions of the installation and increasing the yield of NO. It should also be borne in mind that with increasing pressure, the entrainment of the smallest particles of platinum with gases increases significantly, which increases the cost of commercial acid, as platinum has a high cost. The process of capturing platinum from nitrous gases after the contact apparatus is very complex and does not provide a complete compensation for losses. In modern high-power installations, the optimum pressure is 0.4–0.7 MPa. Contact time The high selectivity of the catalysts allows the process, under conditions of optimal pressures, temperatures, and the O2: NH3 ratio, to reach 97–98% of the NO yield at almost complete ammonia conversion. Since NO can further decompose into elementary N2 and O2 as the contact time increases, the minimum time at which almost complete conversion is achieved and which provides the minimum reactor volume under conditions of almost complete NH3 conversion is selected during the contact time. This time is (1-2)·10-1 s. TEST TASKS 1. The ratio of nitrogen and hydrogen (N2:H2) in the nitrogen-hydrogen mixture of ammonia synthesis is: A) 1:4; B) 1:1; C) 1:2; D) 1:3; E) 2:3.
2. The starting material for nitrogen production is: A) process gas; B) natural gas; C) air; D) water; E) nitric acid. 3. The feedstock for producing hydrogen is: A) ammonia; B) nitrate; C) synthesis gas; D) natural gas; E) coal, coke. 4. The feedstock for the production of hydrogen is: A) water; B) petroleum products; C) ammonia; D) trona; E) pyrolysis gases. 5. In the production of ammonia, the separation of liquid air into its components is carried out by the method of: A) sublimation; B) sublimation; C) neutralization; D) rectification; E) vacuum distillation. 6. The method of air separation in the production of ammonia, based on the difference in boiling points of individual gases, is called: A) rectification; B) sublimation; C) aeration; D) vacuum distillation; E) volatilization. 7. Nitrogen in industry is obtained by: A) decomposition of ammonium nitrate; B) reduction of NO; C) chemical binding of atmospheric oxygen; D) oxidation of ammonia; E) decomposition of ammonia. 8. Method of binding atmospheric nitrogen: A) ammonia-soda;
B) lime C) ammonia D) ammonium; E) oxidative. 9. The nitrogen-hydrogen mixture for the production of ammonia is prepared from nitrogen in the air obtained by the following method: A) physical separation of air; B) selective extraction of nitrogen from the exhaust gases; C) physical absorption of nitrogen-containing gas; D) chemical separation of air; E) cryogenic separation of exhaust gases. 10. Sources of hydrogen for the production of ammonia are: A) natural gas, associated gas, off-gas; B) methanol, air, unsaturated hydrocarbons; C) methyl alcohol, aromatic hydrocarbons; D) methane, water, saturated hydrocarbons, coke oven gas; E) aliphatic hydrocarbons, flue gases. 11. In industry, the hydrogen required for the synthesis of ammonia is obtained by: A) chemical separation of air; B) catalytic conversion of methanol; C) conversion of ethane from exhaust gases; D) methane conversion from natural gas; E) thermal gas neutralization. 12. In industry, the hydrogen required for the synthesis of ammonia is obtained by: A) conversion of carbon monoxide from aqueous or semi-aqueous gas; B) selective extraction of nitrogen from the exhaust gases; C) physical absorption of a hydrogen-containing gas; D) chemical separation of air into components; E) thermal neutralization of a hydrogen-containing gas. 13. In industry, the hydrogen required for the synthesis of ammonia is obtained by: A) physical absorption of a hydrogen-containing gas; B) selective extraction of nitrogen from the exhaust gases; C) electrolysis of water or a solution of sodium chloride; D) chemical separation of air; E) thermal neutralization of a hydrogen-containing gas.
14. In the production of ammonia, the most common systems operating under pressure are: A) partial; B) low; C) high; D) atmospheric; E) medium. 15. The main steps for the preparation of the nitrogen-hydrogen mixture for ammonia synthesis are as follows: A) methanation, СО2 purification, СН4 conversion, CO conversion; B) СО2 purification, СН4 conversion, CO conversion, methanation; C) СН4 conversion, CO conversion, СО2 purification, methanation; D) purification from sulfur compounds, CO conversion, СН4 conversion; E) СН4 conversion, purification from sulfur compounds, CO conversion. 16. The nitrogen-hydrogen mixture is passed through a condensation column in order to: A) capture CO and CO2; B) pressure increase; C) purification from methane; D) purification from water vapor; E) temperature exchange. 17. The nitrogen mixture was purified from СО2 to prevent: A) poisoning of ammonia synthesis catalyst; B) poisoning of methane conversion catalyst; C) overheating of the reaction system; D) poisoning of CO conversion catalyst; E) overcoolings of the reactor. 18. In the reaction of the synthesis of ammonia, an increase in the yield of a product depends on: A) the use of a catalyst; B) reduction in nitrogen concentration; C) pressure reduction; D) an increase in methane concentration; E) temperature reduction. 19. In the reaction of the synthesis of ammonia, an increase in the yield of a product depends on: A) pressure increase; B) reduction in nitrogen concentration; C) pressure reduction; D) an increase in methane concentration; E) the use of a catalyst.
20. The following factors affect the reaction rate of ammonia synthesis: A) a decrease in activation energy; B) lowering the temperature; C) an increase in the concentration of ammonia; D) an increase in activation energy; E) pressure reduction. 21. The optimal conditions for the synthesis of ammonia correspond to the conditions: A) Т = 600-700 ºС, Р = 5-7 MPa, catalyst – Fe-Cr; B) Т = 430-450 ºС, Р = 1 MPa, catalyst – Co-Ni; C) T = 430-530 ºC, P = 30 MPa, catalyst – Pt; D) T = 430-530 ºC, P = 30 MPa, catalyst – Fe; E) T = 700-800 ºC, P = 10 MPa, catalyst – Cr. 22. The following catalysts are used in the technology of ammonia synthesis: A) titanium; B) rhodium; C) nickel; D) iron; E) aluminosilicate. 23. The industrial catalyst used in the synthesis of ammonia: A) activated clay; B) potassium vanadate; C) platinum rhodium; D) promoted iron; E) synthetic zeolite. 24. Industrial catalyst used in the synthesis of ammonia: A) iron chromium; B) ruthenium; C) vanadium; D) cobalt. E) rhodium. 25. The degree of condensation of ammonia from the nitrogen-hydrogenammonia mixture increases depending on the following factors: A) pressure reduction; B) an increase in catalyst activation energy; C) reducing the concentration of hydrogen; D) lowering the temperature; E) increase in nitrogen concentration.
26. The main stages of the technology of synthesis of ammonia: A) synthesis, gas compression, heating, condensation; B) 1 stage of condensation, synthesis, gas compression, 2 stage of condensation; C) condensation, heating, synthesis, gas compression; D) gas compression, synthesis, 1 stage of condensation, 2 stage of condensation; E) synthesis, heating, 1 stage of condensation, 2 stage of condensation. 27. To increase the speed of the ammonia synthesis process it is necessary to: A) increase pressure; B) lower the pressure; C) increase the temperature; D) reduce catalyst consumption; E) increase catalyst consumption. 28. To increase the speed of the ammonia synthesis process it is necessary to: A) increase the temperature; B) lower the pressure; C) lower the temperature; D) reduce catalyst consumption; E) increase catalyst consumption. 29. In the technology of synthesis of ammonia, the main apparatus is: A) an absorber; B) a separator; C) a fluidized bed furnace; D) a synthesis column; E) condenser column. 30. The most important apparatus for the synthesis of ammonia is: A) a neutralization column; B) a distillation column; C) a production column; D) a wash column; E) a synthesis column. 31. Ammonia synthesis columns are made of the following structural material: A) steel; B) cast iron; C) aluminum alloy; D) brass; E) silunite. 32. The temperature of condensation of ammonia, °C: A) 40; B) 60;
C) 25-30; D) 50-55; E) 65. 33. The directions of consumption of commodity ammonia are the production of: A) nitric acid, urea, ammophos; B) sulfuric acid, ammophos; C) hydrochloric acid, ammonium nitrate, ammonium chloride; D) hydrochloric acid, ammonium sulfate; E) milk of lime, TNT. 34. The explosive limit of ammonia in air (NH3, %) corresponds to the values: A) 5-15; B) 29-57; C) 15.5-27; D) 17.5-46.5; E) 45-77. 35. The main stages of obtaining diluted nitric acid: A) electrolysis of sodium chloride solution → hydrogen production → ammonia synthesis; B) contact oxidation of pyrites to SO2 → oxidation of SO2 to SO3 → absorption of SO3 by water; C) methane conversion from natural gas → hydrogen production → ammonia synthesis; D) the conversion of carbon monoxide from water gas → hydrogen production → ammonia synthesis; E) contact oxidation of ammonia to NO → oxidation of NO to NO2 → absorption of NO2 by water. 36. The catalyst for the oxidation of ammonia to nitric oxide in the production of dilute nitric acid is: A) Cobalt; B) Nickel; C) Platinum; D) Vanadium; E) Manganese. 37. The main stages of the technology for producing nitric acid: A) ammonia oxidation, gas cooling, NO oxidation, NO2 absorption; B) ammonia oxidation, NO oxidation, gas cooling, NO2 absorption; C) NO oxidation, gas cooling, ammonia oxidation, NO2 absorption; D) NO oxidation, NO2 absorption, gas cooling, ammonia oxidation; E) NO2 absorption, NO oxidation, ammonia oxidation, gas cooling.
38. The optimal conditions for the process of ammonia oxidation in nitric acid production technology: A) T = 800 °C, P = 0.42 MPa, the catalyst is platinum-rhodium; B) T = 900 °C, P = 0.1 MPa, the catalyst is iron-nickel; C) T = 450 °C, P = 3.5 MPa, the catalyst is iron; D) T = 670 °C, P = 0.01 MPa, the catalyst is iron-nickel; E) T = 550 °C, P = 1.5 MPa, the catalyst is iron-molybdenum. 39. Industrial methods for the production of ammonia, depending on pressure, are divided into: A) under low pressure of 15-25 MPa; B) under an average pressure of 20-30 MPa; C) under high pressure of 125-130 MPa; D) under high pressure of 75-110 MPa; E) under an average pressure of 40-60 MPa. 40. The conditions necessary for the effective operation of the absorption column in the production technology of nitric acid: A) an increase in temperature and pressure; B) a decrease in temperature and pressure; C) a decrease in temperature and an increase in pressure; D) an increase in temperature and an increase in oxygen concentration; E) an increase in oxygen concentration and a decrease in pressure. 41. The neutralization of nitrogen oxides in nitric acid production is carried out in accordance with the reaction: A) NO + 0.5O2 = NO2; B) N2O3 + H2O = 2HNO2; C) 2HNO3 + Ca(OH)2 = Ca(NO3)2 + 2H2O; D) 2NO + CH4 = N2 + CO2 + H2O; E) 3NO2 + H2O = 2HNO3 + NO. 42. The reaction of neutralization of nitrogen oxides in the production of nitric acid: A) N2O3 + H2O = 2HNO2; B) 2NO2 + 4H2 = N2 + 4H2O; C) 2HNO3 + Ca(OH)2 = Ca(NO3)2 + 2H2O; D) NO + 0.5O2 = NO2; E) 3NO2 + H2O = 2HNO3 + NO. 43. For the production of diluted nitric acid from ammonia, the following system is used: A) operating at atmospheric pressure; B) operating under reduced pressure; C) operating at very low temperatures; D) operating at elevated temperatures; E) operating at elevated pressure.
44. To conduct alkaline absorption in the absorption towers for the production of diluted nitric acid, a solution is used: A) CaOH2; B) Na3PO4; C) CaCl2; D) Na2CO3; E) CaCO3. 45. In the production of diluted nitric acid, an apparatus is used to purify air from mechanical and chemical impurities: A) a mesh foam washer; B) an acid absorber; C) a centrifugal scrubber; D) an alkaline absorber; E) a flushing tower. 46. The azeotropic mixture contains HNO3, %: A) 98.9; B) 68.4; C) 100; D) 47.5; E) 92.5. 47. The concentration of commercial nitric acid is, %: A) 45; B) 56; C) 37; D) 47; E) 46. 48. In the production of concentrated nitric acid as a dewatering agent is used: A) H2SO4; B) H2SO3; C) H2S; D) P2O5; E) H3PO4. 49. Direct synthesis of concentrated nitric acid is carried out in accordance with the equation: A) N2О3+H2SO4 → HNSО5+ H2O; B) 3NO2+H2O → 2HNO3+NO; C) 2N2O4 + 2H2O + O2 = 4 HNO3 + Q; D) 2NO2+H2SO4 → HNSO5+ HNO3; E) N2O3+ H2O → 2HNO2. 50. In which apparatus the diluted nitric acid is distilled with concentrated sulfuric acid to obtain concentrated nitric acid: A) denitration towers;
B) absorbing towers; C) rectification plate columns; D) distillation columns; E) plate bubbling columns. 51. In which devices direct synthesis of concentrated nitric acid is carried out: A) cyclones; B) reactors; C) autoclaves; D) scrubbers; E) furnaces. 52. What catalysts are used to oxidize ammonia in nitric acid production technology: A) Fe2O3; B) Сr2O3; C) Ni-Pd-Rh; D) Pt-Pd-Rh; E) Al2O3. 53. What equation corresponds to the reaction of ammonia oxidation: A) 2NO2 N 2O4 ;
B) 2NO O 2 2NO 2 ; C) 4NH 3 5O 2 4NO 6H 2 O. D) NO NO 2 N 2 O 3 ; E) 3NO2 H 2O 2HNO3 NO; 54. In the presence of a catalyst, the oxidation reaction of ammonia can go with the formation of: A) N2; B) NH4 NO3 ;
C) N2O5; D) HNO3 ; E) NO. 55. Reaction: 4NH3 + 5O2 → 4NO + 6H2O – is one of the stages of the following production: A) 1st stage of nitric acid production; B) 2nd stage of the nitrous method for producing sulfuric acid; C) 1st stage for the production of ammonia; D) 3th stage of nitric acid production;
E) the stage of oxidation of the nitrogen-hydrogen mixture of ammonia production. 56. The chemical-technological scheme for the production of diluted nitric acid includes the following stages: A) 3NO2 H2O 2HNO3 NO; B) 4NH3 5O2 4NO 6H 2O; NO 0,5O2 NO2 ;
4NO2 O2 2H2O 4HNO3 ; С) Ca(NO3 ) 2 2HCI CaCI2 2HNO3 ; D) NH4 NO3 NH3 HNO3; E) 2NaNO3 H2SO4 Na2SO4 2HNO3. 57. Stage of production of diluted nitric acid: A) decomposition of ammonia in the presence of a catalyst; B) hydration of nitric oxide; C) absorption of nitrogen dioxide by water; D) oxidation of nitric oxide to nitric pentoxide; E) decomposition of ammonia to nitrogen and hydrogen. 58. The oxidation reaction of ammonia with oxygen in the presence of a catalyst is described by the equation: A) 4NH 3 8O 2 2N 2O5 6H 2O;
B) 2NH 3 O 2 2NO 3H 2 ; C) 4NH3 O2 2N2O 6H2 ; D) 2NH 3 3O 2 N 2 3H 2O 2 ; E) 4NH 3 4O 2 2N 2 O 6H 2 O. 59. In the production of nitric acid, the catalytic stage is the reaction: A) 4NH3 3O2 2N2 6H2O; B) NO + 0.5O2 ↔ NO2 C) 3NO 2 H 2 O 2HNO 3 NO D) 4NH3 4O 2 2N 2 O 6H 2 O;
E) 4NH3 + 5O2 → 4NO + 6H2O. 60. The concentration of nitric acid by conventional distillation is impossible due to: A) its low concentration in the azeotropic mixture; B) the need for high energy costs; C) explosion and fire hazard of the azeotropic mixture; D) loss of acid activity during distillation; E) impossibility of azeotrope separation.
2.3. Technology of production of salts and fertilizers Mineral salts and fertilizers. Areas of use of mineral fertilizers and their classification. Technology of processes of production of potash fertilizers (flotation, halurgical methods). Technology of nitrogen fertilizer production processes. Production of ammonium nitrate (with evaporation and without evaporation of the solution). Carbamide production. Technology of production processes of phosphorus fertilizers. Production of complex and concentrated fertilizers (double superphosphate, ammonium phosphates). Technology of electrothermal processes of production of double superphosphate. Physical and chemical bases of processes and technological schemes. Fertilizers are substances that contain elements necessary for plant nutrition or regulation of soil properties. Classification of fertilizers: Mineral fertilizers are inorganic compounds that contain essential elements for plants. Organomineral fertilizers are humic fertilizers, fertilizers consisting of organic matter and related chemical or adsorption-mineral compounds. Classification of mineral fertilizers by the composition: – nitrogen; – phosphoric; – potassium; – trace elements; – complex; – specialized complex chlorine-free. Classification of organomineral fertilizers: – humic fertilizer; – liquid humic organo-mineral fertilizers and top dressing; – bacterial; – phytohormones; – growth stimulants; 136
– reclamation and drainage. Classification of fertilizers by agrochemical purpose: – direct – source of nutrients for plants; – indirect – serve to mobilize soil nutrients by improving its physical, chemical and biological properties. Classification of fertilizers by the number of nutrients: – simple (one-sided) fertilizers – contain one main nutrient: nitrogen, phosphorus or potassium. These are nitrogen, phosphorus and potash fertilizers; – complex fertilizers (CF) – contain two or three main nutrient elements. They are divided into: – double (such as, for example, nitrogen-phosphorus (NPh), nitrogen-potassium (NP) or phosphorus-potassium (Ph-P)) and – triple (nitrogen-phosphorus-potassium (NPhP)). Complex fertilizers (CF) are divided into: – mixed CF, i.e. mechanical fertilizer mixtures consisting of dissimilar particles; – complex CF, i.e. complex compounds resulting from chemical interaction. According to the state of aggregation, fertilizers are divided into solid and liquid (for example, ammonia water, aqueous solutions and suspensions). Potash fertilizers are used in combination with nitrogen and phosphorus fertilizers. There are chloride and chloride-free potash fertilizers: – potassium chloride (KCl) (up to 60% K2O); – cainite (or kainit) (KCl·MgSO4) (up to 10% K2O); – silvinite (KCl·NaCl) (22-25% K2O); – carnalite (KCl·MgCl2·6H2O) (up to 17% K2O); – potassium nitrate (KNO3); – potassium-magnesia (K2SO4·MgSO4) (up to 30% K2O); – K2SO4 (up to 47% K2O). The main methods for producing KCl are flotation (mark F) and gallurgy (selective dissolution and separate crystallization method) (mark K). Gallurgical preparation of KCl is carried out at Tlye = 105-115°C by vacuum crystallization. 137
Nitrogen fertilizers are used in the form of: – Ammonia fertilizers: ammonium sulfate, ammonium chloride, ammonium bicarbonate, liquid ammonia fertilizers. – Ammonium-nitrate fertilizers: ammonium nitrate, lime nitrate (ammonium sulfonitrate, leina-nitrate, montan-nitrate, ammonium nitrosulfate). – Nitrate fertilizers – sodium saltpeter (sodium nitrate, the chilean saltpeter), calcic saltpeter (calcium nitrate, nitrate calcium, limy saltpeter, the Norwegian saltpeter), potash saltpeter (potassium nitrate, nitrate potassium). – Amide fertilizers – urea (carbamide), calcium cyanamide, urea-formaldehyde fertilizers. The technological process for the production of ammonium nitrate is carried out at T = 220 °C, for 60 minutes, with a ratio of NH3:CO2 = 2:1. The process consists of several stages: – neutralization of nitric acid with ammonia; – evaporation of ammonium nitrate from the solution; – crystallization and subsequent granulation of melt; – cooling; – classification by size; – dusting the product at the exit. The production of urea is based on the interaction of ammonia with carbon monoxide (IV), followed by distillation of the synthesis products and processing of the resulting solutions. In the synthesis of urea, two reversible reactions proceed sequentially: Ammonium carbamide formation: 2NH3+СO2↔CO(NH2)(ONH4) – ∆H, where: ∆H-125.6 kJ
Further, the dehydration of ammonium carbamate to urea: CO(NH2)(ONH4) ↔ CO(NH2)2 + H2O + ∆H where: ∆H = 15.5 kJ (2). 138
The synthesis process is described by the summary equation: 2NH3 + CO2 =CO(NH2)2 + H2O – ∆H, where: ∆H =110.1 kJ Phosphoric fertilizers and phosphoric raw materials The average phosphorus content in the earth’s crust is less than 0.1% (or 0.25% P2O5). The highest concentrations of P2O5 are observed in igneous alkaline and basic rocks. Apatite Ca5[PO4]3F(Cl, OH) is a compound with volcanic origin. Depending on the content, fluorine, chlorine, and hydroxyllapatite are released. Phosphorites are sedimentary rocks, a significant part of which are phosphates and numerous inclusions of other minerals (quartz, glauconite, calcite, clay minerals, etc.). The content of impurity elements is often observed: U, Tr, Sr, less often V, Ti, Zr, etc.: – Simple superphosphate (Ca(H2PO4)2·H2O) – 19-21% P2O5. – Double superphosphate (Ca(H2PO4)2·H2O) – 42-50% P2O5. – Phosphorite flour (Ca3(PO4)2·CaF2) – 19-30% P2O5. Phosphorus in it is in a form inaccessible to plants and can be applicable only on acidic soils. – Precipitate (CaHPO4·2H2O)- 46-48% P2O5. Methods for producing phosphate fertilizers: – mechanical (grinding); – thermal decomposition; – chemical decomposition. Methods of production of double superphosphate: – Chamber method using continuous superphosphate chambers and holding the product for ripening in the warehouse. For the decomposition of phosphates, thermal or extraction acid with a concentration of 50-58% P2O5 is used. – Chamber-flow method using similar chambers, but without operation of warehouse maturation. To decompose phosphates, an extraction acid with a concentration of 47-49% is used. – Flow (tubeless) method using unpaired acid concentration of 30% P2O5.
Production of double superphosphate: 2Сa5(PO4)3F + 7H2SO4 + 6.5H2O = 3[Ca(H2PO4)2H2O] + + 7[CaSO4·0.5H2O] + 2HF + 227.4 kJ; Сa5(PO4)3F + 7H3PO4 + 5H2O = 5[Ca(H2PO4)2·H2O] + HF. Production of phosphoric acid by extraction Sulfuric acid decomposition of calcium phosphate is a heterogeneous irreversible process occurring in the «solid-liquid» system and described by the equation: Сa5(PO4)3F + 5H2SO4 + nH3PO4 + 5mH2O = = (n + 3)H3PO4 + 5CaSO4·mH2O + HF. Conditions for the extraction method for production of phosphoric acid: – the dihydrate method is carried out at 70-80 ºC, a concentration of P2O5 in the liquid phase is 25-32%, the heat of reaction is 384.4 kJ⁄mol; – the hemihydrate method is carried out at 95-100 ºC, the concentration of P2O5 in the liquid phase is 38-48%, the heat of reaction is 371.0 kJ⁄mol. TEST TASKS 1. Nitrogen fertilizers include: A) nitroammophos; B) ammophos; C) urea; D) sylvinite; E) potassium nitrate. 2. Nitrogen fertilizers include: A) potassium nitrate; B) ammophos; C) nitroammophos; D) urea; E) sylvinite. 3. Phosphorus fertilizers include: A) urea; B) saltpeter;
C) precipitate; D) sylvinite; E) kainite. 4. Phosphorus fertilizers include: A) kainite; B) sylvinite; C) nitrate; D) superphosphate; E) carbamide. 5. Complex fertilizers include: A) double superphosphate; B) nitroammophos; C) simple superphosphate; D) carnaite; E) carbamide. 6. Secondary energy resource used in ammonium nitrate production: A) heat of neutralization reaction; B) calcination gas; C) heat of oxidation reaction; D) water vapor; E) secondary steam. 7. The reaction equation for the production of ammonium nitrate: A) 2NH3 + H2SO4 → (NH4)2SO4; B) 2NH3 + H3PO4 → (NH4)2HPO4; C) NH3 + HNO3 → NH4NO3; D) N2 + 3H2 + 2HNO3 → 2NH4NO3; E) NH3 + H3PO4 → NH4H2PO4. 8. The technological process for the production of ammonium nitrate includes: A) decomposition of ammonia; B) neutralization of nitric acid with ammonia; C) concentration of nitric acid; D) decomposition of ammonium nitrate; E) neutralization of sulfuric acid with ammonia. 9. The double superphosphate is produced according to the reaction: A) Ca 3 (PO 4 ) 2 5C 5SiO 2 P2 3CaO 5SiO 2 5CO;
B) CaH 2 PO4 2 4CaOH2 2CaHPO4 2H2 O; C) Ca 3 (PO 4 ) 2 4H 3 PO 4 3Ca(H 2 PO 4 ) 2 ;
D) 2Ca 5 FPO 4 3 7H 2 SO 4 3H 2 O 3Ca H 2 PO 4 2 H 2 O 7CaSO 4 2HF; E) P2 O 5 H 2 O 2HPO 3 .
10. In the production of fertilizers, the raw materials for producing potassium chloride are: A) clay; B) pyrites; C) sylvinite; D) mirabelite; E) potassium sulfite. 11. The translation of insoluble natural salts into soluble is carried out by: A) decomposition by acids; B) decomposition with bases; C) dissolution; D) coprecipitation; E) leaching. 12. One of the main operations for the production of superphosphate: A) granulation of superphosphate; B) dilution of sulfuric acid; C) sulfuric acid concentration; D) dosage of sulfuric acid and phosphate flour; E) grinding of phosphate flour. 13. Methods of processing natural phosphates: A) wet; B) physical and chemical; C) sulfate; D) dry; E) mechanical. 14. One of the main stages of the cyclic process for producing KCl from sylvinite: A) cold leaching of KCl from sylvinite; B) cooling the mother liquor and leaching sylvinite to it; C) leaching of KCl from sylvinite mother liquor after crystallization; D) heating the liquor saturated with NaCl and KCl; E) drying of KCl crystals. 15. In order to intensify the process of sulfuric acid decomposition of phosphates, the following measures are applied: A) dilute sulfuric acid is used; B) sulfuric acid for the decomposition of phosphates is taken in a slight deficiency; C) sulfuric acid for the decomposition of phosphates is taken in a small excess; D) concentrated sulfuric acid is used; E) heating of the superphosphate chamber is increased.
16. The technological process for the production of ammonium nitrate includes: A) decomposition of ammonium nitrate; B) neutralization of ammonia; C) neutralization of nitric acid with ammonia; D) neutralization of sulfuric acid with ammonia; E) leaching of nitrate. 17. The raw material for the production of monosodium phosphate is: A) baking soda, pyrophosphoric acid; B) caustic soda, superphosphoric acid; C) heavy soda, tripolyphosphoric acid; D) soda ash, phosphoric acid; E) table salt, thermal acid. 18. The raw material for the production of monosodium phosphate is: A) H4P2O7 and NaOH; B) H3PO3 and Na3PO3; C) H3PO4 and Na2CO3; D) H5P3O10 and NaHCO3; E) H3P3O9 and Na2SO3. 19. The raw material for disodium phosphate is: A) H3PO4 and Na2CO3; B) H3PO4 and CaCO3; C) H3PO4 and K2CO3; D) H4P2O7 and Na2CO3. 20. The raw materials for the production of di- and trisodium phosphate are: A) H3PO4, Na2CO3, NaOH; B) H3PO3 and Na3PO3, NaOH; C) H4P2O7 and NaOH, NaOH; D) H5P3O10 and NaHCO3, KOH; E) H3P3O9 and Na2SO3, KOH. 21. The main raw materials for the production of sodium tripolyphosphate are: A) superphosphate and sodium chloride; B) phosphoric acid and alkali; C) phosphoric acid and soda; D) phosphorite and sodium sulfate; E) phosphoric acid and sodium chloride. 22. When reactive orthophosphoric acid is neutralized with a soda solution, a reactive salt is obtained: A) monocalcium phosphate; B) sodium dipolyphosphate;
C) sodium pyrophosphate; D) monosodium phosphate; E) dicalcium phosphate. 23. The main stages of the technology for the production of sodium phosphate monosubstituted two-water (monosodium phosphate two-water): A) neutralization of extraction phosphoric acid with a soda solution → filtration → crystallization → centrifugation of the pulp → dissolution of crystals → recrystallization of the solution → packing; B) neutralization of phosphoric acid with soda solution → evaporation of the solution → filtration → crystallization → centrifugation of the pulp → dissolution of crystals → recrystallization of the solution → packing; C) neutralization of thermal phosphoric acid by brine → filtration → crystallization → pulp centrifugation → crystal dissolution → drying → packing; D) neutralization of pyrophosphoric acid with caustic soda solution → filtration → crystallization → pulp centrifugation → crystal dissolution → evaporation → granulation → packing; E) neutralization of sulfuric acid with soda solution → filtration → crystallization → pulp centrifugation → dissolution of crystals → recrystallization of the solution → packing of the finished product. 24. The production of disodium phosphate is based on: A) neutralization of Н3РО4 with soda; C) neutralization of Н3РО4 with ammonia; C) neutralization of Н3РО4 with sodium phosphate; D) neutralization of НРО4 with soda; E) neutralization of H5P3O10 with ammonia. 25. The main stages of the disodium phosphate production process: A) neutralization → granulation → crushing → classification → packaging; B) neutralization → drying → cooling → packing → packaging; C) neutralization → filtration → drying → crushing → cooling → packaging; D) grinding → evaporation → drying → packaging → consumption; E) mixing → drying → crushing → packaging → finished product. 26. In the Na2HPO4 production technology the following concentration of Н3РО4 is applied: A) 56%; B) 30%; C) 43%; D) 25%; E) 66%. 27. In the production of disodium phosphate, the neutralization of H3PO4 occurs at a temperature of: A) 90-105 ºС;
B) 180-210 ºС; C) 250-255 ºС; D) 120-150 ºС; E) 126-180 ºС. 28. Determine the content of P2O5 in sodium tripolyphosphate containing 94% Na5P3O10: A) 54.4% ; B) 66.0%; C) 44.0%; D) 14.0%; E) 18.0%. 29. Determine the content of P2O5 in sodium pyrophosphate containing 99% Na4P2O7· 10H2O: A) 11.5%; B) 24.5%; C) 31.5%; D) 18.0%; E) 15.0%. 30. Calculate the mass of soda (99.5% Na2CO3) to obtain sodium tripolyphosphate weighing 368 kg: A) 266.3; B) 275.0; C) 376.02; D) 78.0; E) 16.02. 31. The content of the main substance (Na5P3O10) in the highest grade sodium tripolyphosphate: A) 98%; B) 88%; C) 94%; D) 78%; E) 95.5%. 32. The temperature of the stage of neutralization in the production technology of sodium tripolyphosphate, °C: A) 80-90; B) 120-130; C) 70-80; D) 30-45; E) 190-200. 33. The temperature of the calcination stage in the production technology of sodium tripolyphosphate, °C: A) 80-90;
B) 120-130; C) 350-380; D) 30-45; E) 290-310. 34. Sodium tripolyphosphate is used as: A) pharmaceutical product; B) reagent for the production of fertilizers; C) fungicide; D) reagent for the production of synthetic detergents; E) defoliant. 35. The composition of the condensed sodium phosphate corresponds to the formula: A) NaNH4HPO4·6H2O; B) NaH2PO4; C) Na4P2O7; D) Na2HPO4 ·7H2O; E) Na3PO4. 36. The main stages of the technology for producing sodium tripolyphosphate: A) mixing, filtering the solution, neutralization, drying; B) solution filtration, drying, neutralization, calcination; C) drying, calcination, solution filtration, neutralization; D) neutralization, solution filtration, drying, calcination; E) neutralization, purification, calcination, drying. 37. The main reaction of the technology for producing sodium pyrophosphate: A) NaH2PO4 = NaPO3 + H2O; B) 2Na2HPO4 = Na4P2O7 + H2O; C) 2H3PO4 + 4NaCl = Na4P2O7 + 4HCl + H2O; D) H3PO4 + Na2CO3 = Na2HPO4 + CO2 + H2O; E) 2Na2HPO4 + NaH2PO4 = Na5P3O10 + H2O. 38. The main stages of obtaining sodium tripolyphosphate: A) neutralization of soda → drying → calcination; B) decomposition → filtration → drying → sieving → crushing → packaging → finished product; C) neutralization of Н3РО4 with soda ash → filtration → drying → calcination; D) decomposition → filtration → washing → drying; E) ammonization → carbonization → filtration → drying → calcination → finished product.
39. Sodium pyrophosphate decahydrate as the main component contains: A) Ca2B6O11·10H2O; B) Na2B4O7·10H2O; C) Mg2B2O5· 10H2O; D) Na4Р2O7·10H2O; E) Ca4B10O19·10H2O. 40. The raw materials for the production of sodium pyrophosphate are: A) H2SO4, Na2CO3; B) H3PO4, К2CO3; C) H3PO4, Na2CO3; D) H3PO3, Na2SO4; E) HNO3, Na2CO3. 41. In the technologies of baking, artificial yeast, cheese and sausage production, in the cement industry and drilling equipment, in the production of synthetic rubber as raw materials are used: A) potassium hydroxide; B) soda ash; C) sodium hydroxide; D) sodium pyrophosphate; E) calcium hydroxide. 42. The main stages of the technology for producing sodium pyrophosphate: A) ammonization of disodium phosphate → carbonization → drying → calcination → finished product; B) decomposition → filtration → drying → packaging → finished product; C) acid neutralization with soda ash → disodium phosphate dehydration → calcination; D) decomposition → filtration → washing → drying → finished product; E) neutralization of ether with soda → drying → calcination. 43. The neutralization of phosphoric acid in the production of sodium pyrophosphate goes according to the equation: A) 2H3PO4 + CaCO3 = Ca(H2PO4)2·H2O + CO2; B) H3PO4 + Na2CO3 = Na2HPO4 + H2O + CO2; C) 4H3PO4 + Ca3(PO4 )2 +3 H2O = 3Ca(H2PO4)2·H2O; D) 3H3PO4 + 2.5Na2CO3 = 2Na2HPO4 + NaH2PO4 + 2,5H2O + 2.5CO2; E) 2H3PO4 + MgCO3 = Mg(H2PO4)2·H2O + CO2. 44. TPA (thermal phosphoric acid) and soda ash are used as raw materials in the production of salts: A) Ca(H2PO4)2·H2O and MgSO4; B) Na3PO3 and CaCl2;
C) Na4Р2O7 and Na5P3O10; D) Mg(H2PO4)2·H2O and CaCl2; E) AlPO4·2H2O and MgSO4. 45. The first form of sodium tripolyphosphate includes: A) lumpy, high temperature (above 450 ºC); B) non-lumpy, low temperature (below 450 ºС); C) soluble, low temperature (below 250 ºC); D) non-hygroscopic, high temperature (above 350 ºC); E) granular, low temperature (below 350 ºC). 46. The second form of sodium tripolyphosphate includes: A) non-compacting, low temperature (below 450 ºC); B) clumping, high temperature (above 450 ºC); C) soluble, low temperature (below 250 ºC); D) non-hygroscopic, high temperature (above 350 ºC); E) granular, low temperature (below 350 ºC). 47. The following additives are used to stabilize the low-temperature form of sodium tripolyphosphate: A) soda ash, ammonium sulfate, limestone; B) precipitate, soda, kieselguhr; C) ammonium nitrate, potash, trona; D) kieselguhr, urea, ammonium nitrate; E) sodium nitrate, urea, limestone. 48. The best method for purifying sodium phosphates from impurities is: A) adsorption; B) neutralization; C) distillation; D) recrystallization; E) absorption. 49. The following substances are used to soften water in power and industrial installations and to prevent precipitation: A) baking soda; B) caustic soda; C) soda ash; D) sodium pyrophosphate; E) sodium tripolyphosphate. 50. In the manufacture of paper for pulp bleaching are used: A) baking soda; B) caustic soda; C) soda ash;
D) sodium pyrophosphate; E) sodium tripolyphosphate. 51. In the textile and leather industries for the bleaching of fabrics and wool washing are used: A) sodium tripolyphosphate; B) diammonium phosphate; C) caustic soda; D) monocalcium phosphate; E) disodium phosphate. 52. In the production of sodium tripolyphosphate, neutralization of phosphoric acid with soda ash is carried out in the apparatus: A) a thermostat; B) a collection tank; C) a reactor; D) an economizer; E) a scrubber. 53. Sodium tripolyphosphate is obtained by neutralizing phosphoric acid with soda ash according to the total reaction: A) 2Na2CO3 + 2H3PO4 = Na4P2O7 + 2CO2 + 3H2O; B) 3Na2CO3 + 2H3PO4 = 2Na3PO4 + 3H2O + 3CO2 ; C) 2.5Na2CO3 + 3H3PO4 = Na5P3O10 + 2.5CO2 + 2.5H2O; D) Na2CO3 + H3PO4 = Na2HPO4 + CO2 + H2O; E) Na2CO3 + 2H3PO4 = 2 NaPO3 + CO2 + 3H2O. 54. The following mineral impurities are part of phosphorite ores: A) sylvinite, green earth, kaolin; B) coal, lime, marble; C) anthracite, kaolin, zeolite; D) glauconite, calcite, dolomite, quartz; E) shale, zeolites, aluminosilicates. 55. The composition of apatite ores includes the following minerals: A) apatite, nepheline, ilmenite, sphene, feldspar; B) apatite, magnetic iron ore; C) apatite, brown iron ore; D) apatite, copper-zinc ore. 56. In apatite ores, the main phosphorus-containing mineral is: A) calcium phosphate; B) kurskite, tincal; C) carbonate, apatite; B) calcium fluoroapatite; E) sulfides of copper, trona.
57. In Kazakhstan, deposits of phosphorites, vanadium and polymetals are mainly found in the mountains: A) Altai; B) Ala-Tau; C) Tien Shan; D) Kara-Tau; E) Ulutau. 58. From apatite-nepheline rock in complex use as a result of chemical processing of nepheline it is possible to obtain: A) gallium, soda, phosphorus fertilizers; B) aluminium, phosphogypsum, zinc, cement; C) soda, gypsum, cement, phosphogypsum; D) potash, soda, aluminium, cement, gallium; E) aluminium, fluoride salts, phosphogypsum. 59. With the complex use of apatite-nepheline rock, by chemical processsing of apatite can be obtained: A) soda, aluminum, zinc, phosphogypsum, salt, fertilizer; B) phosphoric acid, phosphoric fertilizers and salts, gypsum; C) cement, gallium, aluminum, complex fertilizers; D) vanadium, phosphoric acid, soda, phosphogypsum; E) aluminium, fluoride salts, phosphogypsum. 60. According to what characteristics the suitability of phosphorites for acid processing is estimated: A) Na2O content; B) moisture content; C) ratio of CaO to P2O5; D) ratio of MgO to P2O5; E) maintenance of SiO2. 61. In phosphate raw materials, minerals of insoluble residue (i.r.) are present mainly in the form of: A) chlorides; C) chalcedony and quartz; C) dolomite and sylvinite; D) fluorides and chlorides; E) carbonates and phosphates. 62. The content of P2O5 in apatite concentrate is: A) 24-26%; B) 65.4-68.6%; C) 80.5-90.6%; D) 39.4-42.6%; E) 45-65%.
63. In the electric distillation of natural phosphorites as the main product is obtained: A) ferrophosphorus; B) red phosphorus; C) phosphoreum; D) white phosphorus; E) yellow phosphorus. 64. The use of phosphorus slag to obtain cement becomes impossible due to the presence in it: A) Р2О5; B) Sr; C) Pb; D) V2O5; E) As. 65. The composition of the host rock of Karatau phosphorites includes the mineral: A) chalcore; B) dolomite; C) muscovite; D) chrysocolla; E) smithsonite. 66. The modern method of processing fine phosphate raw materials is: A) agglomeration; B) briquetting; C) flotation; D) roasting (burning); E) segregation. 67. For production of phosphoric acid from phosphorites by extraction (sulfuric) method, the minimum content of P2O5 must correspond to: A) 34%; B) 24%; C) 18%; D) 35%; E) 29%. 68. Rich phosphorite ores of the Karatau basin contain P2O5 in the amount of: А) 35-55 %; В) 38-40 %; С) 28-30 %; D) 70-80%; E) 92-95%.
69. Methods for production of double superphosphate: A) flowing; B) cascading; C) chamber; D) fluidized bed; E) flow chamber. 70. Methods for production of double superphosphate: A) flow chamber; B) cascading; C) flow chamber; D) fluidized bed; E) a rotating drum.
2.4. Production of phosphorus and phosphoric acids Electrothermal phosphorus production. The device of electric furnaces. Physico-chemical basis for the production of phosphorus from natural phosphates. Scheme for obtaining elemental phosphorus. Processes for processing of phosphorus into phosphoric and polyphosphoric acids. Acidic methods of processing phosphorus raw materials. Extraction of phosphoric acid and methods for its concentration. Hydrothermal processing of phosphates. Mass fraction of phosphorus in the earth’s crust is 0.08%. The most important phosphorus minerals found in nature are fluorapatite Ca5(PO4)3F and phosphorite Ca3(PO4)2. Phosphorus is one of the most important elements of plant nutrition, as it is a part of proteins. If nitrogen in the soil can be replenished by fixing it from the air, phosphates can only be added to the soil in the form of fertilizers. The main sources of phosphorus are phosphorites, apatites, vivianite and waste from the metallurgical industry – thomas slag, phosphate slag. Phosphorus forms several allotropic modifications, which differ markedly in properties. White phosphorus is a soft crystalline substance. It is composed of P4 molecules. It melts at a temperature of 44.1°C. It is very soluble in CS2 – carbon disulfide, highly poisonous and flammable. By heating white pho-
sphorus, red phosphorus is obtained. It is a mixture of several modifications that have different lengths of molecules. The color of red phosphorus depending on the method and conditions of production can vary from light red to purple and dark brown. Its melting point is 585-600 °C. The most stable modification is black phosphorus, which is similar in appearance to graphite. Red and black phosphorus unlike white phosphorus do not dissolve in carbon disulfide, are not poisonous and are not flammable. Phosphorus is chemically more active than nitrogen. The chemical activity of phosphorus depends on the allotropic modification in which it is found. So, the most active phosphorus is white phosphorus, and the least active – black phosphorus. White phosphorus corresponds to the designation -P4, which corresponds to the composition of its molecules. The red and black phosphorus modifications are usually written as P. The same symbol is used if the modification is unknown. The phosphorus production process consists of the following main stages: preparation of raw materials; sublimation of phosphorus in electric furnaces; purification of furnace gas from dust; condensation of phosphorus. In the production of phosphorus, the initial ore is preliminarily subjected to heat treatment, in which the decomposition of mineral impurities, the combustion of organic components of the ores, and the destruction of the crystalline structure of the basic substance occur. These processes are accompanied by dehydration and decarbonizetion. The raw materials for the production of phosphorus are natural phosphates – apatites and phosphorites, coke or anthracite. Depending on the amount of silica in the feedstock, sand or crushed quartz is introduced into the charge to obtain slags of a certain composition. Raw materials, since the process for producing phosphorus is heterogeneous, are crushed to pieces from 5 to 60 mm and mixed. For completeness of recovery in the mixture, there is approximately 10% excess carbon material. Furnaces for the production of phosphorus operate at an overpressure of 5-15 mm water column and therefore must be carefully sealed. In case of the powerful furnaces, self-sintering electrodes are used. In industry, phosphorus is obtained from calcium phosphate Ca3(PO4)2, which is isolated from phosphorites and fluorapatites. 153
The production method is based on the reaction of reduction of Ca3(PO4)2 to phosphorus. Coke (carbon) is used as a reducing agent. To bind calcium compounds, silica sand SiO2 is added to the reaction system. The process is carried out in electric furnaces (production is referred to as electrothermal). The reaction proceeds according to the equation: 2Ca3(PO4)2 + 6SiO2 + 10C = 6CaSiO3 + P4 + 10CO. The reaction product is white phosphorus (P4). Due to the presence of impurities, technical phosphorus is yellow; therefore, in industry it is called yellow phosphorus. Phosphorus is used for the production of basic phosphate fertilizers: superphosphate and phosphate rock. All phosphate fertilizers are amorphous substances, whitish-gray or yellowish in color. Oxygen acids of phosphorus are products of hydration of phosphoric anhydride. There is orthophosphoric acid (commonly called phosphoric acid) and condensed phosphoric acids. The most studied and important is orthophosphoric acid H3PO4, formed when P4O10 (or P2O5) is dissolved in water. Phosphoric acids Orthophosphoric acid is colorless hygroscopic crystals with density of 1.87 g/cm3 and melting Tmelting = 42.35°C, H3PO4·0.5 H2O crystal hydrate with melting Tmelting = 29.32 °C is known. Density of commonly used 85% H3PO4 at 25 °C is 1.685 g/cm3, viscosity at 20 °C = 47·10-3 ml· sec/m2, specific heat capacity in the temperature range 20-120 °C – 2,064.1 J/kg·K (0.493 cal/g·°C). With water, orthophosphoric acid is mixed in any ratio. Dissociation constants at 25°C are: K1 = 7·10-3, K2 = 8·10-8, K3 = 4·10-13. Orthophosphoric acid is a tribasic acid, of medium strength. It forms three rows of salts-phosphates. When acid solutions are heated, their dehydration occurs with the formation of condensed phosphoric acids. In industry, orthophosphoric acid is obtained by extraction (sulfuric acid) or thermal methods. 154
The extraction method consists in the decomposition of natural phosphates sulfuric and phosphoric acids by reaction: Ca5(PO4)3F + 5H2SO4 + nH3PO4 = (n + 3) H3PO4 + 5CaSO4 + HF Further, the formed acid and insoluble CaSO4 are separated on the filters. The thermal method is based on the combustion of phosphorus to phosphoric anhydride and hydration of the latter to acid: P4 + 5O2 = P4O10 P4O10 + 6H2O = 4H3PO4. Industrial orthophosphoric acid is the most important intermediate product for the production of phosphoric and complex fertilizers and technical phosphates. It is also widely used for phosphating metals, as a catalyst in organic synthesis. Food phosphoric acid is used for preparation of soft drinks, medicines, dental cements, etc. Condensed phosphoric acids are obtained by dehydration of orthophosphoric acids, hydration of phosphoric anhydride with an appropriate amount of water, and by ion exchange from the correspondding condensed phosphates. It is mainly used for production of highly concentrated phosphorus fertilizers, as catalysts in production of petroleum products and in organic synthesis, for production of various polyphosphates. Condensed (polymeric) phosphoric acids are divided into: – polyphosphoric with linear structure of phosphate anion of gneral formula Hn+2PnO3n+1; – metaphosphoric with cyclic structure of phosphate anion of gneral formula (HPO3)n; – ultraphosphoric acids having a branched, reticular structure. Polyphosphoric acids are of the greatest practical importance. Of the polyphosphoric acids, the most fully studied is diphosphoric (pyrophosphoric) acid H4P2O7, isolated in crystalline form in two forms with melting temperatures of 54.3°C and 71.5°C. Pyrophosphoric acid is tetrabasic, dissociation constants at 18 °C are: 155
K1 = 1.4·10-1, K2 = 1.1·10-2, K3 = 2.1·10-7, K4 = 4.1·10-10. Tri-and tetrapolyphosphoric acids are isolated as dilute soluteons. The existence of more condensed phosphoric acids containing up to 12 atoms in the chain is proved by paper chromatography. Polyphosphoric acids are polyelectrolytes. Cyclic metaphosphoric acids (e.g. H3P3O9, H4P4O12) are strong acids. Ultraphosphoric acids are little studied. TEST TASKS 1. The main modifications of phosphorus are: A) grey, white, brown; B) blue, red; C) yellow, orange; D) blue, yellow; E) white, red, black. 2. Modification of phosphorus, which is obtained by electric distillation of natural phosphates, is: A) red; B) black; C) white; D) green; E) purple. 3. The main product produced by the combustion of phosphorus is: A) sulphurous anhydride; B) phosphoreum; C) sulfuric anhydride; D) phosphoric anhydride; E) metaphosphoric acid. 4. Phosphorus-containing substance that is used in the match industry: A) white phosphorus; B) phosphorus chloride; C) a sulfide of phosphorus; D) black phosphorus; E) blue phosphorus. 5. What properties does white phosphorus have: A) soluble in water; B) melts at room temperature;
C) glow in the dark, has a peculiar smell; D) freezes at low temperature; E) does not ignite in air. 6. Basic reaction of phosphorus sublimation: A) Са5(PO4 )3F + 10HNO3 = 3H3PO4 + 5Ca(NO3)2 + HF; B) H3PO4 + Na2CO3 = Na2HPO4 + H2O + CO2; C) Са3(РО4)2 + 5С + 2SiO2 → P2 + 5CO + Ca3Si2O7 – Q; D) Ca5(PO4)3F + 5 H2SO4 + nH2O = 3 H3PO4 + 5CaSO4·nH2O + HF; E) Ca5(PO4)3F + 7H3PO4 + 5H2O = 5Ca(H2PO4)2·H2O + HF. 7. When sublimating phosphorus in the charge as a flux is introduced: A) asharites; B) phosphorites; C) barites; D) silicon earth (silica); E) limestone. 8. When sublimating phosphorus, the moisture of the charge stock reacts with phosphorus, forming: A) FeCl3; B) РН3; C) PCl3; D) P2O5; E) Fe2O3. 9. A useful secondary product of phosphorus sublimation is: A) ferrophosphorus; B) ferrosilicon; C) ferromanganese; D) phosphoreum; E) zinc phosphide. 10. A useful secondary (by-product) of phosphorus sublimation is: A) ferrosilicon; B) red sludge; C) lime slurry; D) silicate slag; E) phosphoreum. 11. A valuable waste of the electrothermal production of elemental phosphorus is high-calorie furnace gas containing 80–85 %: A) NO2; B) NO; C) SO2; D) SO3; E) СО.
12. The composition of the mixture to obtain yellow phosphorus includes: A) apatite, halite; B) phosphorite, coal, nepheline; C) phosphorite, quartz; D) phosphorite, coke, silica; E) apatite, slate, quartz. 13. The method for producing phosphoric acid from elemental phosphorrus is called: A) electrothermal; B) extraction; C) electrochemical; D) absorption; E) catalytic. 14. The electrothermal method for producing phosphoric acid from lowquality phosphate feedstock, unlike extraction, has several advantages: A) low acid concentration; B) purity and high concentration of acid; C) proceeds in the presence of a catalyst; D) low degree of contamination with heavy metals; E) accompanied by high energy consumption. 15. The method for producing phosphoric acid by decomposing natural phosphates with sulfuric acid is called: A) catalytic; B) electrothermal; C) extraction; D) absorption; E) electrochemical. 16. The raw materials for obtaining extraction phosphoric acid are: A) apatites, phosphorites; B) carnalite, nepheline, tincal; C) limestone, bauxite; D gypsum, alunites, soda; E) kainite, sylvinite. 17. Stages of obtaining extraction phosphoric acid: A) decomposition of apatite → pulp filtration → drying → flushing of sediment; B) carnalite decomposition → pulp filtration → flushing of sediment; C) decomposition of phosphates → pulp filtration → flushing of sediment; D) decomposition of phosphates → pulp filtration → drying → calcination; E) decomposition of phosphates → pulp filtration → crystallization.
18. Extraction phosphoric acid is obtained by decomposition of phosphate feedstock with sulfuric acid by the reaction: А) 2Ca5(PO4)3F + 14HNO3 + 3H2O → 3Ca(H2PO4)2·H2O + 7Ca(NO3)2 + 2HF; B) Ca5(PO4)3F + 2H2SO4 → 3CaHPO4 + 2CaSO4 + HF; C) 2Ca5(PO4)3F + 7H2SO4 + 3H2O → 3Ca(H2PO4)2·H2O + 7CaSO4 + 2HF; D) Ca3(PO4)2 + 6HNO3 → 3Ca(NO3)2 + 2H3PO4; E) Ca5(PO4)3F + 5H2SO4 + nH3PO4 + H2O → (n+3)H3PO4 + 5CaSO4·2H2O + HF. 19. The process of obtaining extraction phosphoric acid is affected by: A) apparatus design; B) low pressure; C) low temperature; D) a catalyst; E) impurities. 20. The composition of extraction phosphoric acid includes: A) Н3РО4, Н2SО3, H2O, MgSiF6; B) Н3РО4, H2O, CaO, SO3, MgO, R2O3, F; C) Н3РО4, BaO, NiO, Na2O; D) Н3РО4, H2O, Н2SО4, SiF4; E) Н3РО4, MgO, As, K2O, Н2SО4. 21. What is released into the gas phase in the process of sulfuric acid decomposition of natural phosphates: A) SiF4; B) РН3; C) SО2; D) SiО2; E) Р2О5. 22. What impurities does extraction phosphoric acid obtained by sulfuric acid method contain, as opposed to thermal phosphoric acid: A) SO2, P2O5, Al2O3, CaO, H2O; B) P2O5, Na2O, K2O, Fe2O3, Al2O3; C) SO3, Fe2O3, Al2O3, CaO, MgO, F; D) P2O5, Al2O3, H2O, CaO, Na2O; E) Fe2O3, P2O5, SO2, CaO, CO2. 23. Waste process gases of extraction phosphoric acid production contain: А) HCl, H2SiF6; В) HF, SiF4; С) NH3, SO3; D) HBr, SO2; E) HI, NO2. 24. In the production of extraction phosphoric acid in the process of decomposition of phosphorites with sulfuric acid, gases are formed: A) agglomeration;
C) chloride; C) furnace; D) inert; E) fluoride. 25. In the extraction method for producing phosphoric acid, the degree of extraction of phosphorus from phosphorite is: A) 98%; B) 78%; C) 90%; D) 94%; E) 85%. 26. The hemihydrate method of obtaining wet-process phosphoric acid is different from the dehydrate method by: A) corrosion resistance; B) formation of small crystals of calcium sulfate; C) contamination of acid by calcium sulfate; D) mode of washing the precipitate on the filter; E) low cost. 27. When obtaining extraction phosphoric acid by the dihydrate method, the role of «seed» performs: A) circulating slurry; B) a solvent; C) phosphogypsum, water; D) phosphoric acid; E) sulphuric acid. 28. The dihydrate method of production of extraction phosphoric acid corresponds to the following technological regime: A) T = 65-85 ºC, P2O5 = 28-32%; B) T = 85-95 ºC, P2O5 = 35-47%; C) T = 95-100 ºC, P2O5 = 45-50%; D) T = 110-115 ºC, P2O5 = 39-45%; E) T = 100-125 ºC, P2O5 = 55-58%. 29. The hemihydrate method for production of extraction phosphoric acid corresponds to the following process conditions: A) T = 85-100 ºC, P2O5 = 30-48%; B) T = 65-85 ºC, P2O5 = 28-32%; C) T = 95-110 ºC, P2O5 = 48-50%; D) T = 110-115 ºC, P2O5 = 49-55%; E) T = 115-135 ºC, P2O5 = 55-58%. 30. The technological mode of the anhydrite method for production of extraction phosphoric acid is as follows: A) T = 95-110 ºC, P2O5 = 48-50%;
B) T = 85-100 ºC, P2O5 = 30-48%; C) T = 65-85 ºC, P2O5 = 28-32%; D) T = 110-115 ºC, P2O5 = 49-55%; E) T = 115-135 ºC, P2O5 = 55-58%. 31. The disadvantages of the anhydrite method for producing extraction phosphoric acid are: A) formation of large crystals of anhydrite; B) the possibility of corrosion; C) fewer washes of the precipitate; D) low content of P2O5 in the product; E) low temperature neutralization process. 32. Waste dihydrate method for production of extraction phosphoric acid: A) ferrophosphorus; B) phosphohemihydrate; C) phosphogypsum; D) phosphoanhydrite; E) phospholeum. 33. Waste hemihydrate method for production of extraction phosphoric acid: A) phosphohemihydrate; B) phosphogypsum; C) phosphoanhydrite; D) ferrophosphorus; E) phospholeum. 34. The waste production of wet-process phosphoric acid – phosphorgypsum is used with the aim: A) production of Portland cement, construction gypsum, sulfuric acid, ammonium sulfate; B) production of sodium tripolyphosphate and sulfuric acid; C) production of sulphides and sulphites; D) sulphate and sulphuric acid production; E) production of mineral fertilizers, herbicides, insecticides. 35. The process of utilization of phosphogypsum proceeds by reaction: А) СаS + 3СаSO4 = 4СаО + 4SO2; В) СаSO4 + С = СаS + 2СО2; С) СаSO4 + С = 2СаО + 2SO2 + СО2; D) СаSO4 + 4СО = СаS + 4СО2; E) СаSO4 + 4H2 = СаS + 4H2О. 36. The process of utilization of phosphogypsum to produce ammonium sulfate occurs in accordance with the reaction: А) СаSO4 + 4СО = СаS + 4СО2;
В) СаSO4 + С = СаS + 2СО2; С) СаS + 3СаSO4 = 4СаО + 4SO2; D) СаSO4 + (NН4)2СO3 = (NН4)2SO4 + СаСО3; E) СаSO4 + 4H2 = СаS + 4H2О. 37. Methods of purification of extraction phosphoric acid from impurities are: A) neutralization, evaporation; B) sublimation; C) recrystallization, precipitation; D) filtration, co-precipitation; E) distillation. 38. Method of purification of extraction phosphoric acid from impurities are: A) distillation, osmotic separation; B) sublimation; C) distillation, filtration; D) organic solvent extraction, filtration; E) sublimation. 39. Impurities are removed from the extraction phosphoric acid by filtration: A) Al2O3, Fe2O3; B) K2SiF6, As, SiF4; C) SiO2, CaSO4; D) CaF2, Na2SiF6; E) MgH2PO4, SiF4. 40. For purification of extraction phosphoric acid by extraction method the following substances are used: A) nitric acid, fertilizers, salts; B) sulfuric acid, bases, salts; C) alcohols, esters, ketones, sulfonic acids; D) alkalis, bases; E) salts of magnesium, aluminum, iron. 41. Decomposition of phosphates by nitric acid to form nitric acid extract proceeds by reaction: A) (Са, Мg)CO3 + HNO3 = Ca, Mg(NO3)2 + CO2 + H2O; B) Са5F(PO4)3 + 10HNO3 = 3H3PO4 + 5Ca(NO3)2 + HF; C) FeO + 3HNO3 = Fe(NO3)3 + NO2 + 2H2O; D) CaF2 + 2HNO3 = Ca(NO3)2 + 2HF; E) Al2O3 + 6HNO3 = 2 Al(NO3)3 + 3H2O. 42. The raw material for production of thermal phosphoric acid is: A) yellow phosphorus; B) phosphorites; C) apatites; D) carnallites; E) red phosphorus.
43. The main stages of obtaining thermal phosphoric acid are: A) storage and transportation of phosphorus → combustion and hydration of P4 → gas cooling and hydration of P4O10 → gas purification; В) calcination of the charge → leaching → filtration → smelting → cooling → finished product; С) charge sintering → crushing → classification → packing → gas purification → finished product; D) charge preparation → calcination → quenching and leaching → solution evaporation → dehydration and melting; E) charge mixing → leaching → solution evaporation → melting → gas cooling and hydration P4O10 → gas purification. 44. According to the State Standard, thermal phosphoric acid (technical) of grades 1 and 2 contains: A) not less than 70% H3PO4; B) not less than 70% H3PO3; C) not less than 80% H3PO4; D) not less than 70% H5P3O10; E) not less than 80% H4P2O7. 45. According to the State Standard, reactive thermal phosphoric acid contains: A) 85-87% Н3РО4; B) 30-47% Н3РО3; C) 50-60% Н3РО4; D) 45-55% Н5Р3О10; E) 70-90% Н4Р2О7. 46. The mass fraction of orthophosphoric acid of qualification «pure» and «pure for analysis» is not less than: А) 85% Н3РО4; B) 100% Н3РО4; C) 55% Н3РО4; D) 15% Н3РО4; E) 99% Н3РО4. 47. The raw materials for the production of phosphoric acid of the qualifications «pure» and «pure for analysis» are: A) tripolyphosphoric acid, potassium sulphide and activated carbon; B) extraction phosphoric acid, potassium sulphide and charcoal; C) pyrophosphoric acid, sodium sulfate and activated carbon; D) superphosphoric acid, calcium sulphide and activated carbon; E) thermal phosphoric acid, sodium sulfide and activated carbon. 48. To purify thermal phosphoric acid from arsenic and lead, the following substance is used: А) H2S2О8; B) H2SО3;
C) H2SО4; D) H2S2О3; E) H2S. 49. Dehydration of 85% reactive orthophosphoric acid in graphite furnaces at 250-260 ºС produces: A) pyrophosphoric acid; B) thermal phosphoric acid; C) extraction phosphoric acid; D) superphosphoric acid; E) tripolyphosphoric acid. 50. Neutralization of phosphoric acid in order to obtain reactive calcium salts is carried out in the presence of: A) CaSO4, (NH4)3PO4; B) MgO, MgCO3, Ca(OH)2; C) CaO, Ca(OH)2, CaCO3; D) Ca3(PO4)2, Ca2P2O7; E) NaNO3, CaF2, MgO.
2.5. Catalysis in chemical production The importance of catalysis in the chemical industry. Catalysis and catalysts. Homogeneous and heterogeneous catalysis. Proper-
ties of solid catalysts (shape, degree of dispersion, porosity, strength, etc.). Methods for preparation of industrial catalysts. Types of industrial catalysts. In the chemical industry and related industries (petrochemistry, etc.), more than 90% of existing and newly introduced technologies are catalytic processes. With the use of catalysts, tens of thousands of names of inorganic and organic products are produced, including such as ammonia, nitric and sulfuric acids, methanol, butadiene, styrene, etc., promising methods of production of motor fuels, wastewater treatment and gas emissions are carried out. Most catalytic processes can be organized as continuous, wastefree, low-energy. They are characterized by high technical and economic indicators, provide a high yield of the target product. The use of catalysts allows us to: – intensify chemical-technological processes; – carry out transformations that cannot be implemented in practice without a catalyst due to a very high activation energy; – direct the process in the right direction; – regulate the structure and properties of manufactured products (for example, stereospecific catalysts in the production of synthetic rubbers and plastics). Of particular importance is the use of catalysts in reversible exothermic processes, in which an increase in temperature in order to accelerate the reaction sharply reduces the equilibrium degree of conversion and makes the reaction thermodynamically unresolved. In such processes, the role of catalysts is paramount. Unlike other factors intensifying the chemical process, the catalyst only affects the rate of the chemical reaction and does not affect thermodynamics, only accelerating the achievement of the equilibrium state. At the same time, the catalyst does not accelerate diffusion processes and affects only the rate of processes occurring in the kinetic region. 165
Catalytic processes are divided into: – homogeneous, in which the reacting substances and the catalyst are in the same phase; – heterogeneous, in which the reacting substances and the catalyst are in different phases; – microheterogeneous, flowing in the liquid phase with the participation of catalysts in the colloidal state; – enzymatic, occurring in biological systems under the influence of enzymes. In the chemical industry, heterogeneous catalytic processes in which the phase boundary is the surface of a solid catalyst in contact with a gaseous or liquid phase are most common. Chemical reactions on the surface of the catalyst are a complex process consisting of several successive elementary stages, differing in chemical and physical nature: – diffusion of reagents from the stream to the surface of the catalyst grains (stage of external diffusion); – diffusion of reagent molecules into the pores of the catalyst (stage of internal diffusion); – absorption of reagent molecules on the surface of the catalyst, proceeding in the form of physical absorption or chemisorption (activated absorption); – the stage of chemisorption consists in the formation of an activated complex of the reagent and catalyst and determines specificity of the action of the catalyst in catalytic reactions; – surface chemical reaction as a result of rearrangement of an activated complex or interaction of molecules of one adsorbed reagent with molecules of another; – desorption of the resulting reaction products from the surface of the catalyst; – diffusion of products from the pores of the catalyst to its outer surface (reverse internal diffusion); – diffusion of products from the surface of the catalyst into the stream. In chemical technological processes, not individual catalytically active substances are used, but contact masses representing complex systems, the composition and nature of the components of which should ensure the most effective and stable course of the catalytic process. 166
The contact mass consists of a catalytically active substance (catalyst), an activator and a carrier. The nature of heterogeneous catalysts is very diverse and depends on the type of catalyzed reactions. As catalysts, mainly metals in the free state (platinum, silver, copper, iron) and metal oxides (zinc, chromium, aluminum, molybdenum, vanadium) are used. In cases where two reactions catalyzed by different substances occur simultaneously in the system, bifunctional catalysts consisting of two corresponding components (for example, zinc oxide and aluminum oxide in the process of dehydration and dehydration of ethanol to butadiene) are used. An activator (promoter) is a substance introduced into the contact mass to increase the activity of the catalyst and increase its duration. Activators have a selective effect, so their nature depends on the nature of the catalyst. A carrier (treger) is a material on which a catalyst is applied in order to increase its surface, give the mass a porous structure, increase its mechanical strength and reduce the cost of the contact mass. Pumice, asbestos, silica gel, diatomaceous earth, and porous ceramics are used as carriers in contact masses. Contact masses are made by the methods: – precipitation of hydroxides and carbonates from salt solutions with subsequent formation and calcination; – joint pressing of a mixture of components with a binder; – fusion of components; – impregnation of the porous carrier with solutions of the catalyst and activator. Contact masses are formed in the form of granules, tablets or elements of various configurations. Metal catalysts are made and used in the form of fine nets and blocks. The effectiveness of the use of catalysts in industrial heterogeneous catalytic processes substantially depends on their technological characteristics. These include: – activity; – ignition temperature; – selectivity of action; – resistance to poisons; 167
– porosity; – mechanical strength; – thermal conductivity; – availability; – cheapness. Although the action of the catalysts is different, their common property is an increase in the rate of the catalyzed reaction. The same reaction can occur in the presence of catalysts of different nature and without them. The difference lies in the speed of the process. For example, the rate of hydrogenation of ethylene on a chromium catalyst is 1.0; on a nickel catalyst – 13.0; platinum – 100.0; palladium – 1,000.00; on rhodium – 1,800.00. It follows that rhodium has the greatest activity. Namely, the rate of this reaction, depending on the nature of the catalysts, determines their activity. The most important property of the catalyst is its ability to maintain activity over time, called stability. In homogeneous catalysis, the catalyst can be deactivated due to the accumulation of products in the reaction zone that reduce the concentration of active centers. In heterogeneous catalysis, the decrease in stability is due to both physical and chemical changes. Prolonged temperature exposure leads to recrystallization of the catalyst, which is accompanied by a decrease in its specific surface area and the number of active centers. To prevent the process of recrystallization, special substances are added to the catalyst – promoters, which help to strengthen the crystal lattice of the catalyst embedded in its structure. The structure of the catalyst can also be disturbed due to mechanical and thermal effects. Chemical changes are associated with chemisorption on the surface of the catalyst of impurities and reaction products, which are called catalytic poisons. Over time, coking of the catalyst may occur, resulting in blocking of its active surface by coke deposits, and the overall activity of the catalyst decreases, accordingly. The activity of the coked catalyst can be restored by treating it with air oxygen or water vapor at elevated temperatures. 168
The activity of a catalyst (A) is a measure of its accelerating effect in relation to a given chemical reaction. It is defined as the ratio of the rate constants of catalytic and non-catalytic reactions. =
where E is the activation energy of the reaction without catalyst, Еcat is the activation energy of the reaction with the catalyst. Kcat is the reaction constant with the catalyst. For those cases when the catalytic and non-catalytic reactions are of the same order and, therefore, their pre-exponential coefficients in the Arrhenius equation are equal, the catalyst activity will be determined from the previous equation as: A = eE/RT, where: Е = Еnon-cat Еcat. By reducing the activation energy of the reaction, the catalyst accelerates it by many orders of magnitude. So, for example, for the reaction: 2SО2 + О2 2SО3 the activity of the vanadium catalyst used in it is A = 3·1011, that is, the reaction rate increases hundreds of billions of times. In most cases, the catalyst the stronger reduces the order of the reaction, the higher is its activity. So, for example, if the order of the above reaction without a catalyst is 3, then in the presence of a vanadium catalyst it is only 1.8. The ignition temperature of the catalyst Tignition is the minimum temperature at which the process begins to proceed with sufficient speed for technological purposes. The higher the activity of the catalyst, the lower the ignition temperature. At a low ignition temperature, the working interval between Tignition and the process temperature mode is extended, the reactor design is simplified, the heat 169
consumption for heating the reagents is reduced, and the process mode is stabilized. For exothermic catalytic reactions, at a certain value of Tignition, the rate of heat release becomes equal to the rate of heat removal (heat consumption for heating the reaction mixture and heat entrainment with the reaction products). In this case, Tignition represents the minimum temperature at which the process is autothermic. The selectivity of a catalyst is its ability to selectively accelerate one of the reactions if several reactions are thermodynamically possible in the system. For a complex parallel reaction that proceeds according to the scheme: + ;
where A and B are the initial reactants, R is the target product; D is a byproduct. Then: mR ; S mR mD where mR and mD are the mass of the target and by-product, respectively. Thus, it is possible to define the catalysis process as a selective acceleration of one of the thermodynamically possible reaction directions. It follows from this that at a given temperature T, it is possible to change the difference Еnon-cat – Еcat by selecting a catalyst and, consequently, to direct the process towards the formation of the target product. Selectivity of the catalyst is of great importance in such chemical processes as oxidation of ammonia in production of nitric acid, various processes of organic synthesis. Using catalysts, it becomes possible to obtain various target products from the common raw material. The porosity of the catalyst characterizes its specific surface and, therefore, affects the contact surface of the catalyst with the 170
reagents. For catalytic processes, the availability of the solid catalyst surface for reactants is of great importance, since the larger the contact surface, the higher the rate of conversion to the target products per unit time on the same catalyst. Porosity of the catalyst is expressed as the ratio of free volume of pores to the total volume of the catalyst and is characterized by its specific surface, i.e., surface per unit mass or volume of the catalyst. Modern catalysts have a very developed specific surface area, reaching 10-100 m2/g. The mechanical strength of the contact mass should be such that it does not collapse under the action of its own weight in apparatuses with a fixed catalyst bed and does not wear out in apparatuses with a moving catalyst bed and in FB («Fluidized bed») apparatus. Contact Poison Resistance The practical use of heterogeneous catalytic processes is hindered by the phenomenon of a decrease in catalyst activity during the process. The reasons for this are: 1) a decrease in the active surface of the catalyst during the deposition of dust or reaction products on it; 2) mechanical destruction of the catalyst; 3) poisoning of the catalyst with catalytic (contact) poisons. Catalyst poisoning is a partial or complete loss of its activity under the influence of an insignificant amount of some substances – contact poisons. Contact poisons form surface chemical compounds with activeted catalyst centers and block them, reducing the activity of the catalyst. For each group of catalysts, there are certain types of contact poisons. Catalyst poisoning can be reversible when contact poisons decrease the activity of the catalyst temporarily while they are in the catalysis zone, and irreversible when catalyst activity is not restored after contact poisons are removed from the catalysis zone. Contact poisons can be contained in the reagents entering the catalytic process, and also form as by-products in the process itself. Resistance to contact poisons is an essential property of industrial catalysts. In order to lengthen the life of contact masses in chemical technological processes, a stage of thorough purification of reagents from harmful impurities and a catalyst regeneration opera171
tion (for example, burning high-carbon polymer film enveloping catalyst grains in catalytic cracking processes, oil products, isomerization, and dehydrogenation of organic compounds) are provided. Chemical reactors for conducting heterogeneous catalytic processes are called contact devices. Depending on the state of the catalyst and the mode of its movement in the apparatus, they are divided into: – contact apparatuses with a fixed catalyst bed; – contact apparatuses with a moving bed; – contact apparatuses with a fluidized bed. In addition, contact devices differ in: – the structure of the material flows of the components; – a method of supplying or removing heat; – and a number of other design features. In contact devices with a fixed catalyst layer (contact mass), the contact mass in them is placed in several layers on shelves (shelf units) or in pipes (tubular devices). Multi-shelf contact apparatuses containing several catalyst layers are used in processes with a high positive or negative thermal effect. To maintain the optimal thermal regime of the process, after passing through each catalyst layer, it is heated or cooled by feeding cold gas into the space between the layers, or in external and built-in heat exchangers. The combination of a contact apparatus with devices for removing or supplying heat is called a contact node. For processes occurring at very high speeds, designs are used in which the contact masses are placed in the grids, which ensures their best contact with the reagents. The disadvantages of contact devices with a fixed catalyst bed include: – low productivity of the catalyst due to difficulties in using the inner surface of its grains; – the inability to use a fine-grained catalyst due to its caking; – the difficulty of maintaining optimal thermal conditions; – complexity (layering) of the structure; – the need to stop the contact apparatus for replacing the spent catalyst. 172
Contact devices with a moving catalyst layer operate in the mode of continuous and periodic reactors. In them, the catalyst is sprayed in a moving stream of gas or liquid and transferred with it. In this case, to provide a counterflow, the gas enters the apparatus from below, and the catalyst from above. Contact devices with a fluidized bed of the catalyst are used mainly in the production of organic synthesis, in which the catalyst quickly loses activity and requires continuous regeneration. Therefore, in these installations, as in installations with a moving catalyst layer, the contact device is coupled to the catalyst regenerator. The advantages of contact devices with a moving and fluidized bed of the catalyst include: – the ability to supply reagents with a temperature below the ignition temperature of the catalyst; – easy regeneration and replacement of the catalyst; – possibility of using fine-grained catalysts; – more complete use of the inner surface of the catalyst grains and, as a result, its high performance; – optimal temperature mode of the device. The disadvantages of these types of contact devices include: – rapid abrasion of catalyst grains; – contamination of reaction products with catalyst dust. The operating mode and performance of the contact device depends on such parameters as the contact time, the volume velocity of the gas (liquid) and the specific performance of the catalyst. Contact time – the contact time of the reactants with the catalyst is determined as follows: tc = Vg / Vc, where: Vg is the volume of the gaseous (liquid) reaction mixture passing through the catalyst per unit time, nm3/s; Vc is the catalyst volume (contact mass), m3; tc is the contact time in seconds, s. Volumetric velocity (W) is the volume of the reaction mixture passing through a unit volume of catalyst per unit time, nm3/m3-h or h-1. It should be borne in mind that the second notation is very arbitrary, since volume units differ. 173
TEST TASKS 1. Basic requirements for the properties of solid catalysts: A) amortization and reproducibility; B) selectivity and temperature resistance; C) cheapness and affordability; D) substitutability and amortization; E) porosity and granularity. 2. Technological characteristics of solid catalysts: A) wear resistance; B) cheapness and affordability; C) accessibility. D) activity and stability; E) porosity and crystallinity. 3. Requirements for industrial catalysts: A) high performance; B) specificity; C) reproducibility; D) high conversion rate; E) environmental friendliness. 4. Requirements for industrial catalysts: A) specificity; B) high ignition temperature; C) cycle and periodicity of operation; D) recyclability and environmental friendliness; E) resistance to poisons, mechanical strength. 5. The activity of the catalyst is determined according to the equation: ΔE
A) A e RT ; B) A K 0 e KT
E KT RT
C) A K 0 e K ; D) A K KT ΔE E) A . RT
E KT RT
6. The activity of the catalyst is determined by the corresponding equation:
A) A K 0 e B) A K 0 C)
E KT RT
E KT RT
K КТ ; К ΔE E) A . RT D) A
7. The activity of the catalyst is determined by the ratio:
A) A K 0
E KT RT
K B) A ; K KT RT
A eΔE ;
а1 е ЕКТ/RT ; a 2 e E/RT
ΔE . RT
8. The method of increasing the contact surface of the phases in the gasliquid system: A) an increase in the concentration of reagents; B) bubbling and vigorous stirring; C) a direct-flow motion of phases; D) an increase in temperature; E) pressure reduction. 9. The method of increasing the contact surface of the phases in the gasliquid system: A) a direct-flow phase motion; B) an increase in temperature; C) a decrease in the concentration of reagents; D) counterflow and cross phase movement; E) pressure reduction.
10. The accelerating effect of the catalyst is: A) an increase in temperature; B) an increase in the product yield; C) reducing activation energy and lowering the potential barrier; D) reducing the concentration of the starting reagent; E) increasing the conversion of raw materials into products. 11. The accelerating effect of the catalyst is manifested in: A) an increase in temperature; B) an increase in product yield; C) reducing the concentration of the starting reagent; D) an increase in activation energy; E) an increase in the reaction rate. 12. The main disadvantage of homogeneous catalysis technology: A) the difficulty of separating the catalyst from the production mixture; B) high temperature; C) low conversion; D) low driving force of the process; E) low selectivity. 13. Initiators are substances that: A) increase the driving force of the process; B) increase the resistance of reagents; C) reduce the driving force of the process; D) enter into a chemical reaction and contribute to its acceleration; E) increase activation energy. 14. Initiators are substances that: A) increase the driving force of the process and reduce the activation energy; B) increase the resistance of reagents; C) reduce the driving force of the process and increase the activation energy; D) increase the activation energy and increase the yield of the target product; E) participate in the intermediate interaction and reduce the activation energy. 15. Inhibitors are substances that: A) increase the degree of conversion and increase the speed of the process; B) reduce activation energy and increase product yield; C) reduce the driving force of the process and reduce the activation energy; D) reduce the rate of adverse reactions and prevent the formation of by-products; E) increase activation energy. 16. Inhibitors are substances that: A) increase the rate of adverse reactions; B) reduce activation energy;
C) reduce the driving force of the process; D) shift the equilibrium of the process towards the formation of the starting reagents; E) increase activation energy. 17. A significant increase in the activity of the catalyst with the introduceion of a small addition of another substance is: A) poisoning; B) initiation; C) intensification; D) establishment of additional active centres; E) compounding. 18. A significant increase in the activity of the catalyst with the introducetion of a small addition of another substance is: A) inhibition; B) initiation; C) intensification; D) modification and promotion; E) compounding. 19. Methods used to increase the degree of use of the inner surface of the grain of the catalyst: A) an increase in the grain size of the catalyst; B) a decrease in the grain size of the catalyst, an increase in pore size; C) reduction of the diffusion coefficient, uniform mixing; D) an increase in temperature, an increase in the grain size of the catalyst; E) a decrease in pore size, an increase in the degree of dispersion. 20. Methods used to increase the degree of use of the inner surface of the grain of the catalyst: A) an increase in the grain size of the catalyst; B) a decrease in the diffusion coefficient; C) an increase in temperature; D) a decrease in temperature; E) an increase in the value of free energy. 21. Methods of intensification of the catalytic process occurring in the kinetic region: A) grinding the catalyst and increasing the specific surface area; B) temperature increase and pressure increase; C) a decrease in temperature and pressure; D) pressure reduction in the apparatus; E) organization of fluidization. 22. Methods of intensification of the catalytic process occurring in the kinetic region: A) grinding the catalyst;
B) lowering the temperature; C) an increase in the concentration of starting materials in the volume of the stream; D) a decrease in pressure in the apparatus; E) organization of fluidization. 23. The role of the catalyst in chemical interaction: A) the catalyst takes part in one of the elementary reactions; B) the catalyst does not participate in elementary reactions; C) the catalyst increases the activation energy; D) the catalyst reduces the rate of the overall reaction; E) the catalyst increases the rate of side reactions. 24. The role of the catalyst in chemical interaction: A) the catalyst increases the activation energy; B) the catalyst reduces the activation energy and increases the speed; C) the catalyst only takes part in elementary reactions; D) the catalyst reduces the rate of the overall reaction; E) the catalyst increases the rate of side reactions. 25. Catalysts are classified by the value of the activity index into: A) highly active – a little over 45; B) highly active – more than 50; C) medium active – 45-50; D) inactive – less than 45; E) highly active – more than 55. 26. Catalysts are classified by the value of the activity index into: A) medium-active – about 35; B) highly active – more than 50; C) medium active – 45-50; D) inactive – less than 45; E) medium active – 45-55. 27. The catalysts are classified by the value of the activity index into: A) inactive – less than 35; B) highly active – more than 50; C) inactive – less than 45; D) highly active – more than 55; E) medium active – 45-55. 28. Chemical catalytic processes are called homogeneous if: A) the feedstock, the catalyst and reaction products are in one phase; B) the starting reagents and reaction products are in different phases; C) the feedstock, the catalyst and products are in different aggregate states; D) the starting reagents are in one phase, and the catalyst is in another phase; E) the process proceeds in the gas phase on the surface of the solid catalyst.
29. Chemical catalytic processes are called homogeneous if: A) the starting reagents, the catalyst and the reaction products are in different phases; B) raw materials, catalyst and products are in different aggregate states; C) the starting reagents are in one phase and the catalyst is in another phase; D) there is no phase boundary between the raw material, the catalyst and the reaction products; E) there is a phase boundary between the raw material, the catalyst and the reaction products. 30. The rate of a homogeneous reaction is determined by the equation:
A) V 1 dnj ;
B) V 1 dc ;
s dn A
1 dnA ; v dτ
D) V R F C; E) V k(C
C B )n .
31. The rate of a homogeneous reaction is determined by the equation:
A) V 1 dn A ;
B) V 1 dc ; s dnA C) V R F C; D) V k C A C B ; E) V k(CA C B ) n . 32. The rate of a homogeneous reaction is determined by the equation:
1 dn A ; s dτ
B) V 1 dnj ;
τ dc 1 C) V dc ; s dn A
D) V R F C; E) V k C
Cn B B . 179
33. Methods to intensify homogeneous processes: A) increase in concentration, decrease in temperature; B) increase in pressure and concentration; C) pressure and temperature reduction; D) decrease in concentration and temperature; E) pressure reduction. 34. Methods to intensify homogeneous processes: A) increase in concentration, decrease in temperature; B) decrease in pressure and temperature; C) pressure reduction; D) the use of catalysts; E) decrease in concentration. 35. Chemical catalytic processes are called heterogeneous if: A) reagents, catalyst and products are in one phase; B) the starting reagents and the catalyst are in the same phase, and the products are in different phases; C) occur at the phase boundary; D) only immiscible liquids are components; E) the use of a catalyst is mandatory. 36. Chemical catalytic processes are called heterogeneous if: A) reagents, catalyst and products are in one phase; B) the starting reagents and the catalyst are in the same phase, and the products are in different phases; C) only immiscible liquids are components; D) proceed at the interface-reacting substances-catalyst; E) occur only in the liquid phase. 37. Methods to intensify heterogeneous processes: A) a decrease in temperature, an increase in pressure and concentration; B) an increase in the product yield; C) an increase in the contact surface of the phases and an increase in temperature; D) the use of catalysts, improving the quality of products; E) vigorous stirring. 38. Methods to intensify heterogeneous processes: A) an increase in the product yield; B) an increase in the concentration of the reagent, an increase in the cost of the product; C) the use of catalysts, improving the quality of products; D) the formation of the porous structure of the catalyst; E) vigorous stirring. 39. The disadvantages of contact devices with a fixed catalyst bed: A) contamination of reaction products with catalyst dust;
B) rapid abrasion of the catalyst grains; C) low productivity of the catalyst due to difficulties in using the inner surface of its grains; D) low efficiency; E) bulkiness. 40. The disadvantages of contact devices with a fixed catalyst bed: A) the inability to use a fine-grained catalyst due to its caking; B) contamination of reaction products with catalyst dust; C) a low efficiency; D) bulkiness; E) high catalyst load of the reactor. 41. The disadvantages of contact devices with a fixed catalyst bed: A) the need to stop the contact apparatus to replace the spent catalyst; B) rapid abrasion of the catalyst grains; C) contamination of reaction products with catalyst dust; D) low efficiency; E) bulkiness. 42. The advantages of contact devices with a moving and fluidized bed of catalyst: A) efficiency and stability; B) simplicity of hardware design; C) the purity of the products obtained; D) simplicity of supply of raw materials and simple construction. E) the ability to supply reagents with a temperature below the ignition tem-perature of the catalyst. 43. The advantages of contact devices with a moving and fluidized bed of catalyst: A) simplicity of regeneration and replacement of the catalyst; B) efficiency and stability; C) simplicity of hardware design; D) the purity of the products obtained; E) simplicity of feed and construction. 44. Advantages of contact devices with a moving and fluidized catalyst bed:
A) the full use of the inner surface of the catalyst grains and high performance; B) efficiency and stability; C) simplicity of hardware design; D) ease of supply of raw materials and simplicity of construction. E) a high degree of conversion of the feedstock.
45. A heterogeneous process occurs in the transition region if: A) the chemical reaction proceeds most slowly; B) the convective transfer of the reagent proceeds most slowly; C) the reagent diffusion proceeds most slowly through the boundary gas layer; D) the diffusion rates of the reactants and their chemical interactions are comparable; E) the fastest stage is limiting. 46. A heterogeneous process occurs in the transition region if: A) the diffusion of the gaseous reactant proceeds most slowly through the ash layer; B) the convective transfer of the reagent proceeds most slowly; C) the reagent diffusion proceeds most slowly through the boundary gas layer; D) it is impossible to determine the limiting stage; E) the fastest stage is limiting. 47. The main methods of preparation of active catalysts: A) precipitation and impregnation; B) neutralization; C) absorption; D) suspension and sedimentation; E) casting and impregnation. 48. Basic methods of preparation of active catalysts: A) neutralization and ion exchange; B) absorption; C) magnetic and electromagnetic; D) co-precipitation and sol-gel method; E) sublimation. 49. Substances used as carriers in the manufacture of catalysts: A) pumice, asbestos, silica gel; B) silica, expanded clay, agloporite; C) sodium chloride, sodium sulfate; D) potassium sulfate, sodium sulfide; E) calcium phosphate, calcium carbonate. 50. Minerals used as catalysts: A) bauxites and zeolites; B) phosphorites, gypsum; C) monazites; D) asharites; E) apatites, phosphates.
2.6. Production of hydrochloric acid, chlorine and alkali Electrochemical production. Electrochemical process. Theoretical bases of electrolysis of aqueous solutions and molten medium. Production of chlorine and alkali. Types of chemical baths (diaphragm and mercury cathode). Electrolytic production of hydrochloric acid. Electrochemistry is a branch of physical chemistry that considers systems containing ions (solutions or melts of electrolytes) and processes occurring at the boundary of two phases with the participation of charged particles. Now electrochemistry is divided into theoretical and applied. Thanks to the use of electrochemical methods, it is associated with other branches of physical chemistry, as well as analytical chemistry and other sciences. Electrode processes are processes associated with the transfer of charges across the boundary between the electrode and the solution. The cathodic processes are associated with the reduction of molecules or ions of the reacting substance, the anodic processes are associated with the oxidation of the reacting substance and with the dissolution of the electrode metal. The possibility of a particular electrode process is generally determined by the change of ΔH and ΔS in the course of the corresponding chemical reaction. Knowing these changes, the Helmholtz equation can be used to calculate the minimum value of the voltage that must be applied to the electrodes for this electrode process to occur. For example, based on the thermodynamic data for the reaction: 2H2 + O2 = 2H2O, it was found that the minimum voltage required for the electrochemical decomposition of H2O into H2 and O2 is 1.23 V. However, at this voltage between the Hg cathode and the Pt anode it would take about 400 thousand years to obtain only 1 cm3 of H2. To increase the speed of electrode processes without changing the nature of the electrodes, it is necessary to impose a much larger potential difference on the electrodes. For example, for the passage of an electric current with a density of 1 A/cm2 in the considered system, the potential difference between the electrodes should be 3.5 183
V. In this case, only 35% of the electric energy is spent on the implementation of the electrode process, the remaining 65% is spent on heating the electrolyte. However, the efficiency of electrical energy can be dramatically increased if the Hg cathode is replaced with Pt. This example shows that the thermodynamic approach to the study of the electrode process is insufficient. Much more important is the study of the kinetics of electrode processes. With the help of labeled atoms, it can be shown that the electrode processes always go in two directions. For example, when Cu2+ is reduced on a copper electrode, simultaneously with the reaction: Cu2+ + 2e- → Cu0, Cu ionization occurs, although at a lower rate. In the absence of an external current, the speeds of the forward and reverse electrode processes are equal to each other and equal to the density of the exchange current, which characterizes the intrinsic speed of the electrode process. When passing an external current, the speed of the electrode process in the forward and reverse directions differs by the value of the current density i. Under these conditions, the potential of the electrode differs from its equilibrium value. The shift of the potential of the electrode from its equilibrium value during the electrode process is polarization. Absolute value of polarization (overvoltage) The higher the exchange current density, the smaller the deviation of the electrochemical system from equilibrium at a given value i, and the smaller the overvoltage. Thus, at a given value i, the value characterizes the intrinsic speed of this electrode process. Therefore, the task of electrochemical kinetics is to link the speed value with the current density and other parameters of the electrochemical system by an equation. Knowing this pattern, you can consciously adjust the speed of the studied electrode processes. Electrode processes are heterogeneous, and therefore consist of a series of successive stages. The total speed of the electrode process under these conditions is determined by the speed of the slowest stage. This means that the total velocity value is the sum of the velocity values for different stages: the slowest stage for a given i will give the largest velocity component, in comparison with which other velocity components are neglected. 184
Electrochemical processes are chemical-technological processes in which the energy of an electric current is spent on the implementation of chemical transformations and as a result is converted into chemical energy. In chemical technology, electrochemical processes are used to produce: – halogens; – alkalis; – oxygen and hydrogen by electrolysis of water; – inorganic oxidizers: permanganate, hydrogen peroxide, chlorates, perchlorates, persulfates, hypochlorites, etc.; – lithium, sodium, potassium, magnesium, aluminum, chromium, etc.; – non-ferrous metals (zinc, copper, nickel, silver, etc.) by refining; – alcohols, aldehydes, ketones by anodic oxidation; – nitro derivatives of nitrogen-containing compounds by cathodic reduction; – electroplating-application, production and reproduction of metal copies of protective coatings from non-ferrous metals; – electrotypes. Advantages of electrochemical processes: – simplicity of the hardware design of the technology and lowstep process; – high utilization of raw materials and energy; – simultaneous production of several target products from one raw material; – high purity of products; – the ability to perform transformations and produce products that are not available when using purely chemical methods. The main drawback of these processes is high energy intensity. Main electrochemical processes: electrolysis and galvanic cell. For quantitative characteristics of electrochemical processes the value of the current output (Co) is used: Co = mp/mt 185
where: mproduct and mtheoretical is the amount of energy spent on the production of a unit of production, and the amount of energy theoretically needed to produce a unit of production; mtheoretical is calculated by the formula according to the Faraday law: m =
EJτ K Jτ kg , = F ∙ 10 10
where: F is the Faraday constant (26.8 A·h); E is the chemical equivalent of a substance; J is the current strength, A; τ is the electrolysis time, h; Kx is the electrochemical coefficient, (g / A · h); 103 is a convert of g to kg. Electrolytic production of chlorine and alkali Electrolysis of sodium chloride solution is carried out on the installation in the form of an electrolysis cell with an iron cathode, a perforated coating by a semipermeable membrane, and a graphite anode. The electrolysis process is carried out at a concentration of the initial brine (NaCl) – 305-315 g/l and a temperature of 70-90°C. The concentration of liquor obtained in the electrolysis process is 130-140 g/l. As raw materials for the process, natural salt sources (brine) and sodium chloride solutions are used. The electrolysis proceeds with the formation of chlorine, hydrogen and alkali (caustic soda) in accordance with the reaction equation: NaCl + H O =
0.5H + NaOH
The electrolysis of a sodium chloride solution with a mercury cathode proceeds according to the reaction equation: NaCl + H O = NaOH + 0.5H
The plant consists of a pump for pumping mercury, a mercury cathode and graphite anodes located in the electrolyzer and decomposer. The process is carried out at room (ambient) temperature. Solutions of pure table salt are used as raw materials. The purity and yield of the resulting products are several orders of magnitude higher, but the process is energy-consuming and harmful to the environment. Production of hydrochloric acid Hydrochloric acid is a solution of hydrogen chloride gas HCl in water. It is a hygroscopic colorless gas with a pungent smell. Concentrated hydrochloric acid usually contains 36-38% of hydrogen chloride and has a density of 1.19 g/cm3. It smokes in the air, as it is released from the gaseous HCl, which when combined with the moisture of the air forms droplets of acid. Dilute acid containing up to 10% hydrogen chloride is often used. Dilute solutions do not emit gaseous HCl and do not smoke in either dry or wet air. Pure acid is colorless, and technical acid has a yellowish tint caused by traces of compounds of iron, chlorine and other elements (FeCl3). Hydrochloric acid is used in the chemical, food industry, nonferrous and ferrous metallurgy. It produces a variety of salts for laboratory or technical use. In metallurgy, it is used for etching the surface of metals. Hydrochloric acid is used in the analysis of ferrous and non-ferrous metals. In a mixture with nitric acid, it is used to dissolve platinum and in the processing of precious metals. Significant amounts of dry hydrogen chloride are used in industry to produce various chlorine derivatives from unsaturated hydrocarbons (for example, ethyl chloride, vinyl chloride, etc.). In industry hydrochloric acid is obtained by the following main methods: – sulphate; – synthetic; – from waste or exhaust gases (gas side) of a number of processes. It should be noted that the first two methods are now losing their industrial value. 187
The production of synthetic hydrochloric acid involves two successive stages: – synthesis of hydrogen chloride from chlorine and hydrogen; – absorption of hydrogen chloride by water. The raw materials for the production of synthetic hydrochloric acid are hydrogen, chlorine and water. Hydrogen is produced in the production of caustic soda and chlorine by diaphragm, mercury and membrane electrochemical methods. The hydrogen content in the technical product is not less than 98 vol.%. The oxygen content is regulated at the level of 0.3-0.5%. When using hydrogen obtained by mercury electrolysis of sodium chloride, the mercury content should be no more than 0.01 mg / m3. Depending on the method of removal of heat absorption, which reaches 72.8 kJ/mol processes are divided into isothermal (at a constant temperature), adiabatic (without heat exchange with the environment) and combined. The sulfate method of HCI production is based on the interaction of sodium chloride NaCl with concentrated sulfuric acid H2SO4 at 500-550 °C. Reaction gases coming from muffle furnaces contain 50-65% hydrogen chloride, and gases from fluidized bed reactors up to 5% HCl. It is currently proposed to replace sulfuric acid with a mixture of SO2 and O2 using Fe2O3 as a catalyst and conducting the process at a temperature of 540°C. The synthetic method of HCI production is based on direct synthesis of hydrochloric acid through a chain reaction of combustion: Н2 + CI2 → 2HCI +184.7 kJ The reaction is initiated by light, moisture, solid porous substances (charcoal, porous platinum) and some minerals (quartz, clay). Synthesis is carried out in combustion chambers with an excess of H2 in 5-10%. The chambers are made of steel, graphite, quartz, and refracttory bricks. The most modern material that prevents contamination of the product is graphite impregnated with phenol-formaldehyde resins. To prevent explosive nature of combustion reagents, they are mixed directly in the flame of the burner. 188
In the upper zone of the combustion chambers, heat exchangers are installed to cool the reaction gases to 150-160 °C. The capacity of modern graphite furnaces reaches 65 t/day (in terms of hydrochloric acid containing 35% HCl). In the case of hydrogen deficiency, various modifications of the process are used. For example, a mixture of Cl2 with water vapor is passed through a layer of porous hot coal: CO + H2O + CI2 = 2HCI + CO2 To obtain synthetic hydrochloric acid, it is possible to use waste chlorine from the condensation stage, electrolytic chlorine, and evaporated chlorine. More than 90% of HCl is obtained from waste hydrogen chloride produced during chlorination and dehydrochlorination of organic compounds, pyrolysis of organochlorine wastes, metal chlorides, production of potassium non-chlorinated fertilizers, and others. Offgases contain various amounts of hydrogen chloride, inert impurities (N2, H2, CH4), sparingly soluble organic substances (chlorobenzene, chloromethanes), water-soluble substances (acetic acid, chloral), acidic impurities and water. In industry, adiabatic absorption schemes are most widely used to produce hydrochloric acid. Waste gases are introduced into the lower part of the absorber, and water (or dilute hydrochloric acid) is introduced countercurrently to the upper one. The dissociation of HCl into elements becomes noticeable at very high temperatures – more than 1,500° C. During adiabatic combustion of a stoichiometric mixture of chlorine and hydrogen at a temperature of 0 °C, the theoretical flame temperature is 2,500 °C. In practice, due to some dissociation of HCl, the flame temperature decreases to 2,200-2,400 °C. An excess of one of the components of the gas mixture (usually hydrogen) somewhat lowers the combustion temperature. At ordinary temperature, in the absence of light rays, the reaction of the formation of HCl from elements proceeds very slowly. When a mixture of chlorine and hydrogen is heated or under the influence of bright light, an explosion occurs due to a chain reaction: 189
hv → Cl·+ Cl·+H2 → HCl+H·+Cl2 → HCl+Cl·+H2 → HCl+H· and so on. In the presence of oxygen, the reaction of chlorine with hydrogen slows down. The direct connection of chlorine and hydrogen is carried out in contact furnaces made of heat-resistant steel, their height sometimes reaches several meters and a diameter of more than half a meter. In the lower part of the furnace there is a burner consisting of two pipes inserted one into the other. Dry chlorine enters the inside of the pipe, and hydrogen enters the outside of the pipe. At the exit, hydrogen and chlorine burn with the formation of a flame; since the reaction generates heat (22,000 cal per g-mol HCl), the flame temperature reaches 2,400 °C. In order to prevent contamination of hydrogen chloride with chlorine, a certain excess of hydrogen is fed into the burner, up to 5% against the theoretically necessary amount. The resulting hydrogen chloride is then sent from the top of the furnace for absorption by water or transferred to a liquid state. Previously, the absorption of hydrogen chloride was carried out in special vessels, cooled to remove generated heat by cold water or air acting on the principle of counterflow. Liquid hydrogen chloride from the collection is sent to casting in steel cylinders. It contains up to 99.5% HCl. It should be noted that in dry hydrogen chloride, the bond between chlorine and hydrogen is covalent and therefore, without heating, it does not react with iron and most other metals. According to the State Standard, hydrochloric acid must contain at least 27.5% HCl. Hydrogen chloride can also be converted to a liquid state. To do this, hydrogen chloride is sent to the refrigerator, where the condensation of hydrochloric acid vapor occurs. Further drying is carried out in a tower irrigated with sulfuric acid. Then, hydrogen chloride is compressed by a compressor to 100 atm. for the purpose of purification from oxides. TEST TASKS 1. The main indicator of the electrochemical process: A) reagent concentration; B) product yield; C) current output; D) the degree of purity of the product; E) product concentration.
2. The main indicator of the electrochemical process: A) product yield; B) energy efficiency; C) the degree of purity of the product; D) product concentration; E) current strength. 3. The main indicator of the electrochemical process: A) reagent concentration; B) the degree of purity of the product; C) product concentration; D) specific energy consumption; E) current strength. 4. The main methods of producing hydrogen chloride for the synthesis of hydrochloric acid: A) synthesis from chlorine and hydrogen; B) synthesis from ammonium chloride; C) isolation from hydrochloric acid; D) thermal decomposition of chlorides; E) electrolysis of sodium chloride. 5. The main methods of producing hydrogen chloride for the synthesis of hydrochloric acid: A) sulfate synthesis by reaction of NaCl and H2SO4; B) synthesis from metal chlorides; C) synthesis from ammonium chloride; D) isolation from hydrochloric acid; E) thermal decomposition of chlorides. 6. The main methods of producing hydrogen chloride for the synthesis of hydrochloric acid: A) extraction of hydrogen chloride from products of chlorination of organic compounds (chlorination, dehydrochlorination, pyrolysis, etc.); B) synthesis from metal chlorides; C) isolation from hydrochloric acid; D) thermal decomposition of chlorides; E) synthesis by electrolysis of table salt. 7. Electrolysis of the NaCl solution proceeds with the formation of: A) sodium; B) oxygen; C) water; D) hydrogen; E) sodium oxide.
8. Electrolysis of the NaCl solution proceeds with the formation of: A) sodium; B) oxygen; C) chlorine; D) sodium hypochlorite; E) sodium oxide. 9. Electrolysis of the NaCl solution proceeds with the formation of: A) sodium; B) oxygen; C) water; D) sodium hypochlorite. E) sodium hydroxide. 10. The current output is the ratio of the mass of the substance actually obtained by electrolysis to the mass of the substance: A) which should be obtained according to the equation of chemical reactions; B) electrolyte; C) which is consumed in the process; D) which should be obtained according to Faraday’s law; E) empirically calculated. 11. The current output is the ratio of the mass of the substance actually obtained by electrolysis to the mass of the substance: A) electrolyte; B) which is consumed in the process; C) empirically calculated; D) according to the estimated quantity; E) after electrolysis. 12. The current output is the ratio of the mass of the substance actually obtained by electrolysis to the mass of the substance: A) which should be obtained according to the chemical reaction equation; B) electrolyte; C) empirically calculated; D) theoretically calculated; E) after electrolysis. 13. Main indicators of the electrochemical process: A) product yield, reagent concentration, energy coefficient; B) current output; C) reagent concentration, current efficiency; D) product concentration, degree of conversion; E) the degree of purity of the product, the degree of use of electricity, power consumption coefficient.
14. Main indicators of the electrochemical process: A) product yield, reagent concentration, power factor; B) product concentration, degree of transformation; C) the degree of purity of the product, the degree of use of electricity, the power consumption coefficient; D) the extent to which electricity is used; E) electricity selectivity. 15. Main indicators of the electrochemical process: A) reagent concentration, current output; B) product concentration, degree of transformation; C) the degree of purity of the product, the degree of use of electricity, the power consumption coefficient; D) power consumption coefficient; E) electricity selectivity. 16. The Faraday number is: A) the amount of electricity required to produce 1 kg of a substance; B) the amount of electricity needed to produce a unit of a substance; C) the amount of electricity required to produce 1 g-eq. of a substance; D) the amount of electricity needed to carry out the process; E) the ratio of theoretical energy consumption to practical consumption. 17. The Faraday number is: A) the amount of electricity required to produce 1 kg of a substance; B) the amount of electricity needed to produce a unit of a substance; C) the amount of electricity needed to carry out the process; D) a physical quantity equal to 96,485.33 (83) coulomb · mol-1; E) a physical quantity that depends on the charge on the electrode. 18. The Faraday number is: A) the amount of electricity needed to produce 1 kg of a substance; B) the amount of electricity needed to produce a unit of a substance; C) the amount of electricity needed to carry out the process; D) the ratio of theoretical energy consumption to practical consumption; E) a physical quantity equal to the product of the Avogadro number and the elementary charge of the electron. 19. According to the second law of Faraday, when passing the same amount of electricity through various electrolytes, the amount of substance obtained by electrolysis is directly proportional to: A) the amount of electricity; B) electric current; C) electrolyte area; D) the technological mode of electrolysis; E) electrochemical equivalent.
20. According to the second Faraday law, when passing the same amount of electricity through various electrolytes, the amount of substance obtained by electrolysis is directly proportional to: A) electric current; B) electrolyte area; C) the technological mode of electrolysis; D) the equivalent mass of the element; E) electron charge. 21. According to the second law of Faraday, when passing the same amount of electricity through various electrolytes, the amount of substance obtained by electrolysis is directly proportional to: A) the amount of electricity; B) electric current; C) electrolyte area; D) the technological mode of electrolysis; E) time of electrolysis. 22. Electrolysis of an aqueous solution of NaCl is carried out at temperatures: A) 10-13 ºC; B) 45-50 ºC; C) 85-90 ºC; D) 90-105 ºC; E) 55 ºC. 23. Electrolysis of an aqueous solution of NaCl is carried out at temperatures: A) 90-110 ºC; B) 55-65 ºC; C) 45-54 ºC; D) 82 ºC; E) 50 ºC. 24. Electrolysis of an aqueous solution of NaCl is carried out at temperatures: A) 115-125 ºC; B) 900-1,050 ºC; C) 450-540 ºC; D) 89 ºC; E) 78 ºC. 25. Advantages of electrochemical production methods over chemical ones are as follows: A) simplification of the technological process; B) high yield of the target product; C) cost-effectiveness; D) low power consumption; E) production of only one product.
26. Advantages of electrochemical production methods over chemical ones are as follows: A) better utilization of raw materials and energy; B) partial use of raw materials and energy; C) high yield of the target product; D) cost-effectiveness; E) low power consumption. 27. The advantages of electrochemical production methods over chemical ones are as follows: A) partial use of raw materials and energy; B) simultaneous production of several products; C) high yield of the target product; D) profitability; E) low power consumption. 28. Technological parameters of the process of liquefaction of chlorine: A) P = 10-12 atm; B) P = 10-12 atm, T = -50 ºC; C) P = 3-6 atm, T = 25 ºC. D) T = 1 atm, Tambient; E) T = 40 atm, T = -50 ºC; 29. Technological parameters of the process of liquefaction of chlorine: A) P = 10-12 atm, T = -50 ºC; B) P = 3-6 atm, T = 25 ºC; C) T = 1 atm, Tambient; D) T = 1 atm T = -50 ºC; E) T = 1 atm, T = 10 ºC. 30. Technological parameters of the process of liquefaction of chlorine: A) P = 10 atm, T = 25 ºC; B) T = 1 atm, Tambient; C) P = 3-6 atm, T = -5 ºC to +25 ºC; D) P = 10 atm, T = -50 ºC; E) T = 1 atm, Tambient. 31. Disadvantage of the sulphate method of hydrogen chloride production: A) uneconomical process; B) hydrochloric gas contains only 30-40% HCl, which makes it possible to obtain hydrochloric acid containing 27.5 % HCl; C) bulkiness of the furnace; D) nitric acid is consumed; E) hydrochloric acid is obtained with a concentration of no more than 10 %.
32. Disadvantage of the sulphate method of hydrogen chloride production: A) uneconomical process; B) bulkiness of the furnace; C) the presence of impurities in the gas that pollute hydrochloric acid; D) nitric acid is consumed; E) explosion hazard. 33. The disadvantage of the sulphate method of hydrogen chloride production: A) the complexity of the process; B) high consumption of nitric acid; C) high consumption of sulfuric acid; D) explosion hazard; E) hydrochloric acid is obtained with a concentration of no more than 10 %. 34. The advantage of the synthesis of hydrogen chloride from elements over the sulfate method: A) high efficiency of the process; B) hydrochloric gas contains only 80-90% HCl, which allows one to obtain hydrochloric acid with a concentration of more than 31%; C) compactness of the furnace; D) hydrochloric gas contains only 80-90% HCl, which allows one to obtain hydrochloric acid with a concentration of more than 35%; E) sulfuric acid is consumed in small quantities. 35. The advantage of the synthesis of hydrogen chloride from elements over the sulfate method: A) hydrochloric acid is obtained in a high degree of purity; B) nitric acid is not consumed; C) compactness of the furnace; D) hydrochloric gas contains only 80-90% HCl, which allows one to obtain hydrochloric acid with a concentration of more than 35%; E) sulfuric acid is consumed in small quantities. 36. The advantage of the synthesis of hydrogen chloride from elements over the sulfate method: A) process efficiency. B) hydrochloric acid is obtained with a concentration of more than 31%; C) convenient furnace design; D) hydrochloric acid is obtained with a concentration of more than 35%; E) low consumption of sulfuric acid. 37. One of the industrial methods of producing hydrochloric acid: A) ammonia. B) sulfate;
C) electric arc; D) absorption; E) sulfuric acid. 38. One of the main industrial methods of producing hydrochloric acid: A) off-gas (waste gas); B) sulfite; C) absorption; D) ammonia; E) electrolysis. 39. The synthetic method for the production of hydrochloric acid includes the steps: A) synthesis of HCl from chlorine and hydrogen, absorption by water; B) production of chlorine by electrolysis of salt, production of hydrogen by pyrolysis of hydrocarbons, synthesis of HCl; C) production of gaseous HCl in the process of splitting hydrocarbons, absorption by water; D) production of hydrochloric acid by irrigation of the products of electrolysis of a salt solution; E) decomposition of hydroxylamine hydrochloride. 40. According to the State Standard, hydrochloric acid must contain HCl, %:
A) not more than 17.5; B) not less than 27.5; C) less than 25; D) not more than 15; E) about 20.
2.7. Production of soda products Production of soda products. Production of lime and carbon dioxide. Production of soda by the ammonia method Soda is produced in the form of several main products: – soda ash – anhydrous sodium carbonate Na2CO3; – bicarbonate soda – sodium bicarbonate NaHCO3, or drinking soda; – crystalline soda Na2CO3·10H2O and Na2CO3·H2O; – caustic soda (NaOH). 197
Ordinary soda, depending on the method of preparation, is Leblanc and ammonia. The latter is a cleaner product. In addition, soda is either in the calcined (anhydrous, calcined), or crystalline form. It contains up to 10 parts of water. Natural soda is found in solid form as part of the throne mineral Na₂CO3·NaНCO3·2Н2О; as an aqueous solution, it is found in soda lakes and alkaline mineral springs, as well as in the ash of some plants. Until the beginning of the XIX century natural soda was used, but with the increase in its consumption, the need arose for the technological production of soda on a large scale. Modern industrial soda production uses sodium carbonate (or crude bicarbonate) of sodium, as well as carbon dioxide from lime kilns, as a raw material for producing purified baking soda. Currently, the world produces several million tons of soda per year. Soda and soda products: – soda (Na₂CO3) – from the ash of the plant Salsola Soda; – sodium salts of carbonic acid: Na₂CO3 – soda ash (the product of heating soda crystalline hydrate over Ca), Na2CO3·10Н2О – sodium carbonate decahydrate, 62.5% water; Na2CO3 · Н2О; Na2CO3 · 7Н2О – washing soda, NaНCO3 – baking soda (bicarbonate, sodium bicarbonate, sodium bicarbonate). NaOH – caustic soda. Raw Material: – algae and coastal plants; – minerals: – nacholite – NaHCO3; – throna – Na2CO3 · NaHCO3 · 2H2O; – sodium (soda) – Na2CO3 · 10H2O; – termonatrite – Na2CO3 · Н2О; – davsonite → soda and alumina. The largest reserves are discovered and developed in the United States (40% of the minerals, green river, lake Searles), Africa (Tanzania, lake Natron), Russia (Transbaikalia and Western Siberia).
History of soda production In 1791 N. Leblanc (France) developed a method for producing soda from glauber’s salt (Na2SO4), chalk and charcoal at T = 1,000 °C: 1) Na2SO4 + 2C → Na2S + 2CO2↑, 2) Na2S + CaCO3 → Na2CO3 + CaS (solid melt), 3) Na2CO3 solid + CaS solid + Н2О → Na2CO3 liquid + CaSO4↓, 4) Recrystallization 5) Dehydration of soda crystalline hydrate by calcination. Preparation of Glauber’s salt: 2NaCl + H2SO4 → Na2SO4 + 2HCl ↑. Until the beginning of the 19th century, soda (Na2CO3) was obtained from the seaweed ash and coastal plants. In 1764, Laxman proposed a method for producing soda by sintering natural sodium sulfate by the reaction: Na2SO4 + charcoal → Na2CO3. Laxman’s method was tested at a glassworks in Taltsinsk (near Irkutsk) in 1784. In 1861 E. Solve (Belgium) developed a method for producing soda from a solution of sodium chloride: NaClsolution + NH3 + CO2→ NaHCO3↓ + NH4Cl → calcination: 2NaHCO3↓ (140-160 °С) → Na2CO3 + CO2↑ + Н2О, 2NH4Cl + Ca(OH)2 → CaCl2↓ + 2NH3↑ + 2H2O CaCO3 → CaO + CO2 → Ca(OH)2 In 1930 a method for producing soda according to Hou (Hou Debang) was developed: NaCl solution + NH3 + CO2 (Т = 40°С) → NaHCO3 ↓ + NH4Cl → → (cooled to Т = 10°С) → NH4Cl ↓ → → the solution is fed back to the process, 199
NaHCO3 ↓ → calcinate (Т, °С) → Na2CO3 + CO2 ↑ + Н2О. The main difference of this method is that CaCO3 is not used. The chemical scheme for production of soda by the ammonia method was proposed by Ernest and Solve: СaCl₂ → electrolysis → Са → СaCO₃ Sodium bicarbonate is widely used in the chemical industry for production of dyes, foams, organic products, fluoride reagents, household chemicals, fillers in fire extinguishers, for separation of carbon dioxide and hydrogen sulfide from gas mixtures. In the light industry, it is used in the manufacture of rubber soles, artificial leather, for tanning and skin neutralization. In the textile industry, it is used for finishing silk and cotton fabrics. In the food industry, sodium bicarbonate is used in bakery, manufacture of confectionery products, preparation of drinks, etc. In medicine, it is used for preparation of anti-TB drugs, antibiotics, solutions for injection, etc. In metallurgy, it is used for deposition of rare-earth metals, for flotation concentration of ores. Lime production Lime is an astringent material obtained by firing and subsequent processing of limestone, chalk and other calcareous-magnesian rocks. Pure lime is a colorless product, poorly soluble in water (about 0.1% at 20 °C), with a density of 3.4 g/cm3. Lime was mainly used for preparation of binding solutions in the construction of buildings. Over time, its application has expanded, and now it and substances based on it are used in many industries, agriculture, and even in environmental protection. In the metallurgical industry, lime allows the metal to be purified from phosphorus, sulfur, or silicon impurities that are formed when oxygen is introduced into molten iron or steel. Lime is introduced into the production process at three stages: – firstly, for the production of pellets (semi-finished products of iron that are loaded into the smelter); – secondly, to purify the material from sulfur before melting; 200
– thirdly, after oxygen is mixed with the fused material, lime in a solid or crushed state is added to the furnace to form hard slags that can be easily removed at this stage. Such use makes the steel ultra-pure: it is in this form that it is most appreciated in the market. Lime is also actively used for the production of metal products: in the creation of wire or shaped elements, it is indispensable as a kind of «lubricant». In the first case, the wire without problems extends through the matrix, and the finished product easily departs from the form sprinkled with «chalk». The use of quicklime in the production of colormet has also been mastered: the smelting of precious metals is not complete without it. It is known that gold and silver ore are ground at a certain stage, mixed with a solution of cyanide and lime. The latter provides the necessary acid balance, which prevents the evaporation of harmful substances into the atmosphere. No less well-known to us copper or lead are also produced not without the participation of this universal material. The harm from dangerous fumes is reduced when they are passed through the socalled «lime milk». Raw materials for the production of air lime are calcareous-magnesian carbonate rocks (limestones, chalk, dolomitized limestones, dolomites, etc.). The composition of limestone includes calcium carbonate (СаСО3) and a small amount of various impurities (clay, quartz sand, dolomite, pyrite, gypsum, etc.). Theoretically, the calcium carbonate is composed of 56% CaO and 44% CO2. It occurs as two crystalline minerals – calcite and aragonite. When heated to a temperature of 300400°C, aragonite turns into calcite, crumbling into a powder. In dolomitic limestones, dolomite CaCO3 · MgCO3 is present as an impurity. Theoretically, it consists of 54.27% CaCO3 and 45.73% MgCO3, or 30.41% CaO, 21.87% MgO, and 47.72% CO2. Dolomite rocks contain dolomite and clay, sand, glandular and other impurities. Typically, clean and dense limestones are fired at temperatures up to 1,100-1,250°C. The more carbonate rock contains impurities of dolomite, clay, sand, etc., the lower the optimum calcination temperature (900–1,150°С) to obtain softly burnt lime. Such lime is well quenched with water and gives a dough with high plastic properties. 201
The best quality lime is obtained from rocks in which impurities are present in the form of uniformly distributed particles up to 1 μm in size. Impurities of gypsum are undesirable, with their content in lime even about 0.5-1%, the plasticity of the lime test is greatly reduced. Iron impurities (especially pyrite) significantly affect the properties of lime, which even at temperatures of 1,200°C and more cause formation of fusible eutectics during firing, which contribute to the intensive growth of large crystals of calcium oxide, slowly reacting with water during quenching and causing phenomena associated with the concept of «burnout». The main operations for production of lump quicklime: extraction and preparation of limestone, preparation of fuel and calcination of limestone. Before firing, limestone is suitably prepared: sorted by size of pieces and crushed. In mine furnaces, it is most expedient to burn limestone separately in fractions of 40-80, 80-120 mm across, and in rotary kilns – 5-20 and 20-40 mm. Limestone calcination is the main technological operation in the production of air lime. At the same time, a number of complex physical and chemical processes that determine the quality of the product occur. The following processes occur during firing: – complete decomposition of CaCO3 and MgCO3, CaCO3 into CaO, MgO and CO2; – formation of a high-quality product with an optimal microstructure of particles and their pores. If clay and sand impurities are present in the raw material, then during firing reactions with formation of silicates, aluminates, calcium and magnesium ferrites occur between them and carbonates. The decomposition reaction (decarbonization) of the main component of limestone – calcium carbonate: СаСО3 ↔ СаО+СО2 Theoretically, 1790 J or 1,790 kJ per 1 kg of CaCO3 are consumed for decarbonization of 1 mole of CaCO3 (100 g). In terms of 1 kg of the resulting CaO, the costs are 3,190 kJ. 202
The firing duration is also determined by the size of the pieces of the fired product. The main difference in the technologies for the production of lump quicklime is the firing method. Limestone is fired in various furnaces: mine, rotary, fluidized bed, in suspension, etc. The most widespread are lime kilns. Three zones are distinguished by the nature of the processes occurring in a mine furnace, by its height. In the upper part of the furnace there is a heating zone – in it the raw material is dried and heated by hot flue gases, organic impurities burn out. In the middle part of the furnace there is a firing zone, where the temperature of the fired material varies between 850-1,200-900 °C, where limestone decomposes and carbon dioxide is removed from it. In the cooling zone in the lower part of the furnace, lime is cooled by air from below from 900 to 50-100 °C; the air in turn heats up and enters the firing zone to maintain combustion. TEST TASKS 1. Caustification of soda solution is carried out at a temperature of: A) 140 ºC; B) 110 ºC; C) 150 ºC; D) 80 ºC; E) 100 ºC. 2. Caustification of soda solution is carried out at a temperature of: A) 140 ºC; B) 190 ºC; C) 85 ºC; D) 150 ºC; E) 40 ºC. 3. Caustification of soda solution is carried out at a temperature of: A) 90 ºC; B) 100 ºC; C) 110 ºC; D) 150 ºC; E) 40 ºC. 4. The optimal concentration of soda solution in the process of caustification: A) 75-80%;
B) 10-15%; C) 25-30%; D) 55%; E) 48%. 5. The optimal concentration of soda solution in the process of caustification: A) 35-40%; B) 20%; C) 48%; D) 12%; E) 55%. 6. The optimal concentration of soda solution in the process of caustification: A) 70-80 %; B) 25-30 %; C) 20 %; D) 65 %; E) 14 %. 7. The temperature regime of the chemical method for production of caustic soda: A) 35-55 ºC; B) 99-120 ºC; C) 45-54 ºC; D) 80-100 ºC; E) 180 ºC. 8. The temperature regime of the chemical method for production of caustic soda: A) 180-190 ºC; B) 45-54 ºC; C) 180 ºC; D) 90 ºC; E) 35 ºC. 9. The temperature regime of the chemical method for production of caustic soda: A) 25-35 ºC; B) 180-200 ºC; C) 450-540 ºC; D) 85 ºC; E) 30 ºC. 10. One of the advantages of the electrochemical method for producing caustic soda: A) high purity of the product;
B) low energy consumption; C) high process speed; D) high degree of caustification; E) low degree of caustification. 11. Advantage of the electrochemical method for producing caustic soda: A) low energy consumption; B) high process speed; C) high degree of caustification; D) low degree of caustification; E) formation of a highly concentrated, chemically pure solutions; 12. Point out one of the advantages of the electrochemical method for producing caustic soda: A) low energy consumption; B) high process speed; C) high degree of caustification; D) the process refers to low-waste production; E) the process is cheaper. 13. Advantage of the lime method for producing caustic soda: A) high degree of caustification; B) low energy consumption; C) high process speed; D) high concentration of alkali; E) low degree of caustification. 14. One of the advantages of the lime method of producing caustic soda: A) high process speed; B) high concentration of alkali; C) low degree of caustification; D) low cost of the target product; E) low raw material consumption. 15. Point out one of the advantages of the lime method of producing caustic soda: A) high degree of caustification; B) high process speed; C) high concentration of alkali; D) low degree of caustification; E) the principle of energy conservation is fulfilled. 16. The process of producing caustic soda by electrolysis of an aqueous solution is carried out: A) on an iron cathode and a copper anode; B) on platinum electrodes;
C) on an iron cathode and a ruthenium anode; D) on an iron cathode and a graphite or titanium anode; E) on an iron cathode and a copper anode. 17. Electrolysis of an aqueous solution of table salt for production of caustic soda is carried out: A) on a mercury cathode and a graphite or titanium anode; B) on nickel electrodes; C) on platinum electrodes; D) on an iron cathode and a nickel anode; E) on an iron cathode and a copper anode. 18. Production of caustic soda by electrolysis of an aqueous solution of table salt is carried out: A) on an iron cathode and a nickel anode; B) on nickel electrodes; C) on platinum electrodes; D) by diaphragm or mercury methods; E) on a nickel cathode and an anode. 19. In the processes of obtaining caustic soda by electrolysis of an aqueous solution as the anode is used: A) copper-cobalt anode impregnated with resin; B) platinum anode; C) ruthenium oxide anode; D) graphite anode impregnated with linseed oil; E) copper anode. 20. In the production of caustic soda from an aqueous solution by electrolysis as the anode is used: A) platinum anode coated with a layer of titanium oxide; B) nickel anode coated with a layer of titanium oxide; C) titanium anode coated with a layer of titanium oxide; D) ruthenium oxide anode; E) cobalt anode. 21. Electrolysis of an aqueous solution of table salt is carried out on the following anodes: A) ruthenium oxide anode; B) nickel anode coated with a layer of titanium oxide; C) graphite or titanium anodes; D) cobalt anode; E) a copper anode coated with a layer of ruthenium oxide. 22. The main stages and technological process of production of sodium hydroxide, chlorine and hydrogen from NaCl by electrolysis: A) distillation of electrolysis products;
B) grinding of raw materials; C) flotation separation of electrolysis products; D) extraction separation of electrolysis products; E) preparation of raw materials for electrolysis. 23. The process of production of sodium hydroxide, chlorine and hydrogen from NaCl by electrolysis passes through the following stages: A) distillation and purification of electrolysis products; B) flotation separation of electrolysis products; C) extraction separation of electrolysis products; D) purification of electrolysis products; E) distillation of electrolysis products. 24. The stages of the technological process for production of sodium hydroxide, chlorine and hydrogen from NaCl by electrolysis are: A) flotation separation of electrolysis products; B) grinding raw materials for electrolysis; C) processing of electrolysis products; D) extraction separation of electrolysis products; E) distillation and purification of electrolysis products. 25. The main advantage of the membrane method of electrolytic production of caustic soda compared with diaphragm: A) sodium ions and partially water do not pass through the membrane to the cathode; B) the polymer membrane separates the anode and cathode space and facilitates the passage of NaCl from the brine to the cathode; C) the polymer membrane promotes the transfer of OH ions to the anode of the cell; D) the polymer membrane separates the anode and cathode space and prevents NaCl from entering the brine on the cathode; E) no advantage. 26. Indicate the advantages of the membrane method of electrolytic production of caustic soda in comparison with the diaphragm: A) the polymer membrane facilitates the transfer of OH- ions to the anode of the electrolyzer; B) the polymer membrane separates the anode and cathode space and facilitates the ingress of NaCl from the brine to the cathode; C) the polymer membrane prevents the transfer of OH- ions to the anode of the electrolyzer; D) sodium ions and partially water do not pass through the membrane to the cathode; E) both processes increase the yield of alkali. 27. Advantage of the membrane method of electrolytic production of caustic soda in comparison with the diaphragm method: A) the polymer membrane separates the anode and cathode space and facilitates the penetration of NaCl from the brine to the cathode;
B) chlorine is released at the anode and excreted together with the depleted brine, and sodium ions and partially water pass through the membrane to the cathode and participate in the formation of lye of a given concentration; C) the polymer membrane facilitates the transfer of OH-ions to the anode of the electrolyzer; D) sodium ions and partially water do not pass through the membrane to the cathode; E) both processes increase the yield of alkali. 28. Advantage of the membrane method of electrolytic production of caustic soda in comparison with the diaphragm method: A) the membrane type electrolyzer contains from 20 to 25 cells; B) capacity of the membrane electrolyzer is up to 50 thousand tons per year; C) the membrane type electrolyzer contains from 40 to 80 cells; D) the load on the cell (current) of the membrane electrolyzer does not exceed 15 kA; E) both electrolyzers are cost-effective. 29. Indicate the advantage of the membrane method of electrolytic production of caustic soda in comparison with the diaphragm: A) the load on the cell (current) of the membrane electrolyzer does not exceed 17 kA; B) capacity of the membrane electrolyzer is up to 50 thousand tons per year; C) the membrane type electrolyzer contains from 20 to 25 cells; D) capacity of the membrane electrolyzer is up to 80 thousand tons per year; E) the output and cost of production from both electrolyzers are comparable. 30. One of the advantages of the membrane method of electrolytic production of caustic soda in comparison with the diaphragm: A) capacity of the membrane electrolyzer is up to 50 thousand tons per year; B) the load on the cell (current) of the membrane electrolyzer does not exceed 7.5 kA; C) the membrane type electrolyzer contains from 20 to 25 cells; D) the load on the cell (current) of the membrane electrolyzer does not exceed 20 kA; E) both electrolyzers are cost-effective. 31. The main stages of obtaining soda ash and sodium bicarbonate according to the Solve method: A) grinding sodium bicarbonate; B) calcination of limestone; C) neutralization of ammonia solution; D) obtaining sodium bicarbonate; E) synthesis of ammonia. 32. One of the stages of obtaining soda ash and sodium bicarbonate according to the Solve method: A) preparation of limestone for roasting; B) calcination with the formation of soda; C) calcination of limestone; D) separation of CaCl2; E) dissolution of limestone.
33. One of the stages of obtaining soda ash and sodium bicarbonate according to the Solve method: A) obtaining a solution of limestone; B) preparation of limestone for roasting; C) regeneration of ammonia; D) separation of CaCl2; E) grinding of raw materials and synthesis of ammonia. 34. The stage of obtaining soda ash according to the Leblanc method: A) 2NaCl + H2SO4 = Na2SO4 + 2HCl; B) ammonia regeneration: 2NH4Cl + CaO = CaC12 + H2O + 2NH3 C) calcination with the formation of soda: 2NaHCO3 = Na2CO3 + CO2 + H2O; D) separation of CaC12; E) grinding of raw materials and synthesis of ammonia. 35. One of the stages of obtaining soda ash according to the Leblanc method: A) separation of CaCl2; B) calcination with the formation of soda: 2NaHCO3 = Na2CO3 + CO2 + H2O; C) Na2SO4 + 3C + CaO = Na2CO3 + CaS + 2CO; D) grinding of raw materials and synthesis of ammonia; E) synthesis of ammonia. 36. Specify the steps of producing soda ash by the LeBlanc method: A) calcination with the formation of soda: 2NaHCO3 = Na2CO3 + CO2 + H2O, partial regeneration of sulfur from calcium sulfide; B) ammonia regeneration: 2NН4Сl + CaO + H2O = СаС12 + 2NN3 and separation СаС12; C) leaching, evaporation and crystallization of Na2CO3·10H2O, calcination with the formation of Na2CO3, partial regeneration of sulfur from calcium sulfide; D) regeneration of sulfur from calcium sulfide; E) 2NaC1 + H2SO4 = Na2SO4 + 2HCl, neutralization of HCl with alkali, partial regeneration of sulfur from sodium sulfate. 37. During calcination of limestone in a mine furnace, the following processes occur: A) complete decomposition of calcium and magnesium carbonates to their oxides; B) formation of low quality soda; C) deposition of clay and sand; D) separation of calcium carbonate from magnesium carbonate; E) production of iron and silicon oxides. 38. If there are clay and sand impurities in the limestone, the following reactions occur during firing between them and the carbonates with formation of: A) aluminum, iron and silicon carbonates;
B) silicates, aluminates, ferrites of calcium and magnesium; C) iron, silicon and aluminum oxides; D) iron and silicon silicates; E) aluminosilicates. 39. The following kilns are mainly used for calcining limestone: A) horizontal; B) mine; C) vertical; D) shelves; E) latticed. 40. Zones of the mine kiln for calcination of limestone are divided into: A) grinding, heating, cooling zones; B) heating, firing, cooling zones; C) drying, firing, condensing zones; D) firing and cooling zones; E) grinding, firing and drying zones.
2.8. Aluminum production Properties and directions of application of aluminum. Raw materials for production of aluminum. The general scheme of aluminum production. Alumina production. Electrolytic production of aluminum. Cleaning and refining of aluminum. Production of cryolite and coal products. Aluminum is widespread in nature and takes the first place among metals, and is also one of the most popular elements. The raw materials for the production of aluminum are bauxite: HAlO2 (diasporas); Al(OH)3 (hydroargelite); Al2O3 · 2SiO2 · 2H2O (coalinite); α-Al2O3 (corundum); nepheline: (Na, K)2O · Al2O3 · 2SiO2 (from fluoroappatite); alunites: (Na, K)2SO4 · Al2 (SO4)3 · 4Al (OH)3; kaolins (clays): Al2O3 · SiO2 · MeOx · xH₂O; feldspar (orthoclase): K2O Al2O3 · 6SiO2. The composition of bauxite includes such basic components as: alumina (28-70%); silica (0.5-20%); Fe2O3 (2-50%); TiO2 (0.1%) and other oxides. Alumina consists of hydroxides, corundum and kaolinite. 210
An important component of aluminum-containing raw materials is the silicon module (Al2O3/SiO2): bauxite (30-60% Al2O3); nepheline concentrate (30% Al2O3); alunites (20% Al2O3); kaolins (up to 40% Al2O3). Alumina production There are three methods for producing aluminum oxide from ores: – acidic; – electrolytic; – alkaline. Technologies for producing alumina from bauxite include alkaline processing and melt electrolysis: 1) Alkaline treatment (Si < 5% Bayer method; if > 5% – sintering method) (3 t of bauxite + 0.25 t (42%) NaOH = 1 t Al2O3; E = 300 kWh): HAlO₂ + NaOH → NaAlO₂ + H₂O; Al(OH)₃ + NaOH → NaAlO₂ + H₂O; SiO₂+ NaOH → Na₂SiO₃ + H₂O; 2Al(OH)₃ → Al₂O₃ + 3H₂O (1,200 °C, calcination); 2) Melt electrolysis (10-13%) of Al2O3 in cryolite 3NaF·AlF3 (Na2AlF6) (I = 150 000 A; Ubath = 4-5 B; T = 950-960 °C; products: Al and O2) The device and principle of operation of the electrolysis furnace: Tmelting Al₂O₃ = 2,050 °С; T melting cryolite = 1,100 °C. The cell is an iron casing, lined with refractory bricks from the inside; the bottom is the cathode (blocks of compressed coal); top anode – aluminum frames filled with coal briquettes. 211
Al₂O₃ = Al³ + AlO₃³⁻ Al³+ 3ē = Al (at the cathode) 4AlO₃³⁻ – 12 ē = 2Al₂O₃ + 3О₂ (at the anode) The generalized electrolysis equation is as follows: 2 types of electrodes are used: self-firing and fired (continuous). C + O = CO; C + O₂ = CO₂ Al₂O₃ + 3C = 2Al + 3CO 2Al₂O₃ + 3C = 4Al + 3CO₂ Refining of aluminium Refining is carried out in order to purify Al from impurities and dissolved gases. The selected batch of aluminum is chlorinated in a vacuum ladle, hydrogen and metals are converted to chlorides and mechanically separated from Al: Al + Mg + Ca → MgCl ₂, CaCl₂, AlCl₃ + Al Absolutely pure aluminum is obtained by subsequent zone melting of the metal in an inert gas or vacuum. It has high electrical conductivity at cryogenic temperatures. Production of aluminum is completed with its purification up to 99.99%. Recycling of secondary raw materials A quarter of the total demand for aluminum is met by recycling of raw materials. Shaped casting is poured from recycled products. Aluminum combines such exceptional properties as low density, low electrical and thermal resistance, high plasticity, corrosion resistance, high mechanical strength, which ensures its wide application, both as a metal and as an alloy. Pure aluminum due to its plasticity has found application in the production of foil, widely used for production of electrolytic capacitors and packaging materials for food products (tea, dairy products, confectionery). Due to the low cost and high conductivity, aluminum has almost completely replaced copper from the production of conductor products (installation and winding wires, cables, busbars, etc.). 212
In the metallurgical industry, aluminum is used as a reducing agent in the production of a number of metals (for example, chromium, calcium, manganese) by aluminothermic methods, for deoxidation of steel, welding of steel parts. The dominant part of the total world production of aluminum (about 83 %) is made up of deformed alloys, including about 43% for production of sheets, more than 18% for pressed semi – finished products, and 7% for production of wire and foil. In addition, about 15% of primary aluminum is used for shaped casting and about 1% is spent on production of powders. The main uses of aluminum: – transport (aircraft structures, engines, pipes, ship hulls, railcar finishing) – 18-21%; – construction (hangars, structural parts of buildings, frames, storage, chemical products – 24-30%); – electrical industry (cables, busbars, capacitors, rectifiers – 12-14%); – machine and instrumentation (motors, cylinder blocks, pumps, crankcases, film and photo equipment; control and measuring equipment – 5-7%); – containers and packaging materials (food foil, containers for canning and storage of products – 14-17%); – household items (dishes, cutlery – 7-10%); – other consumption – up to 10%. The vast majority of aluminum is used in the form of alloys that have high mechanical properties and depending on the application are divided into two large groups – deformable (about 80% of the total production of alloys) and foundry (about 20%). Castings of various configurations are obtained from casting alloys. Widely known casting alloys are based on aluminum-silumins, in which the main alloying additive is silicon (up to 13%). TEST TASKS 1. Advantages of cryolite as a solvent for alumina in aluminum production:
A) dissolves alumina; B) gives alloys with alumina whose melting point is much higher than the melting point of pure alumina;
C) poorly dissolves alumina; D) contains many positive ions, in addition to aluminum; E) forms a stable alloy with alumina. 2. Advantages of cryolite as a solvent for alumina in aluminum production:
A) gives alloys with alumina whose melting point is much higher than the melting point of pure alumina; B) gives alloys with alumina whose melting point is much lower than the melting point of pure alumina; C) poorly dissolves alumina; D) contains many positive ions, in addition to aluminum; E) dissolves aluminum well. 3. Advantages of cryolite as a solvent for alumina in aluminum production: A) gives alloys with alumina whose melting point is much higher than the melting point of pure alumina; B) does not contain more positive ions than aluminum; C) poorly dissolves alumina; D) contains many positive ions, in addition to aluminum; E) forms a stable alloy with alumina. 4. Specify how impurities affect Al properties: A) significantly degrade mechanical properties; B) contribute to the strengthening of forging; C) promote wear resistance; D) contribute to reducing brittleness; E) contribute to increased elasticity. 5. Indicate how impurities affect the properties of Al: A) contribute to the reduction of fragility; B) contribute to the strengthening of forging; C) contribute to wear resistance; D) significantly degrade electrolytic and casting properties; D) have no influence. 6. Specify how impurities affect the properties of Al: A) contribute to increased wear resistance; B) contribute to an increase in malleability; C) reduce the corrosion resistance; D) contribute to reducing fragility; E) contribute to increased elasticity. 7. Raw materials for aluminum production: A) zeolite, aluminosilicate; B) alumina, diatomite;
C) bauxite, nepheline, alunite, kaolin; D) clay, zeolite; E) zeolite, kaolin, alunite. 8. Raw materials for aluminum production: A) alumina, diatomite; B) zeolite, aluminosilicate; C) clay, zeolite; D) zeolite, kaolin, alunite; E) bauxite, nepheline. 9. Raw materials for aluminum production: A) zeolite, aluminosilicate; B) clay, zeolite; C) zeolite, kaolin, alunite; D) alunite, kaolin; E) bauxite, zeolite, clay. 10. Production of aluminium involves: A) process chain-alumina-aluminum; B) process chain-ore-aluminum; C) production of alumina, production of fluoride salts and cryolite; D) production of alloy mass; E) production of aluminum wire. 11. Production of aluminium involves: A) production of coal products, production of electrolytic aluminum; B) process chain-alumina-aluminum; C) production of alloy mass; D) production of aluminum wire; E) production of aluminosilicates. 12. Production of aluminium involves: A) process chain-ore-aluminum; B) process chain-ore-alumina-aluminum; C) production of alloy mass; D) production of aluminum wire; E) production of aluminosilicates. 13. The primary method of aluminum production: A) the method of hydrolysis; B) the method of electrolysis; C) method of Bayer; D) solvation method; E) flotation separation method.
14. The primary method of aluminum production: A) wet method; B) saturation method; C) the method of electrolysis; D) method of hydrolysis; E) flotation separation method. 15. The primary method of aluminum production: A) the method of hydrolysis; B) saturation method; C) the method of electrolysis; D) the method of leaching; E) solvation method. 16. Methods of extraction of alumina from ore: A) crystallization; B) melting and leaching; C) chemical-thermal, acidic and alkaline; D) leaching and crystallization; E) flotation and gallurgical. 17. Methods for separation of alumina from ore: A) pyrometallurgical; B) melting and leaching; C) crystallization; D) leaching and crystallization; E) gallurgy method. 18. Methods for separation of alumina from ore: A) leaching and crystallization; B) crystallization; C) hydrometallurgical; D) gallurgic; E) flotation and gallurgic. 19. Method of electrolytic separation of metallic Al from its oxide: A) electrolysis of the melt of Al2O3 and Na3AlF6 in the presence of fluorides of Al, Ca, Mg; B) electrolysis of molten cryolite; C) melting and leaching of γ-Al2O3; D) leaching and crystallization of aluminosilicate; E) electrolysis of the melt of Al2O3 and Na3AlF6 in the presence of rare metals. 20. Method of electrolytic separation of metallic Al from its oxide: A) electrolysis of cryolite-alumina melt; B) melting and leaching of γ-Al2O3;
C) leaching and crystallization of aluminosilicate; D) electrolysis of the melt of Al2O3 and Na3AlF6 in the presence of rare metals; E) electrolysis of the Na3AlF6 melt in the presence of metal fluorides. 21. Method of electrolytic separation of metallic Al from its oxide: A) melting and leaching of γ-Al2O3; B) electrolysis of Al2O3 and Na3AlF6 melt in the presence of metal fluorides; C) leaching and crystallization of aluminosilicate; D) electrolysis of the melt of Al2O3 and Na3AlF6 in the presence of rare metals; E) electrolysis of the Na3AlF6 melt in the presence of metal fluorides. 22. Introduction of metal fluorides into the melt during the electrolytic separation of Al from oxides causes: A) better electrolysis of the alumosilicate melt; B) enhanced electrolysis of Na3AlF6 melt; C) improved leaching and crystallization of aluminosilicate; D) better electrolysis of molten Al2O3; E) higher electrical conductivity of the electrolyte. 23. Introduction of metal fluorides into the melt during the electrolytic separation of Al from oxides causes: A) a decrease in the melting temperature of the electrolyte; B) an increase in melting and leaching of aluminum; C) enhanced electrolysis of the Na3AlF6 melt; D) improved leaching and crystallization of aluminosilicate; E) improved electrolysis of the Al2O3 melt. 24. Introduction of metal fluorides into the melt during the electrolytic separation of Al from the oxides causes: A) better wettability of the anode by the melt of the electrolyte; B) enhanced electrolysis of Na3AlF6 melt; C) improved leaching and crystallization of aluminosilicate; D) improved electrolysis of molten Al2O3; E) improved electrolysis of the alumosilicate melt. 25. In electrolytic production Al with Tmelting = 938 ºC eutectic is obtained when the content of cryolite in the melt is equal to: A) from 15 to 20% by wt.; B) 15% by wt.; C) 35% by wt.; D) 45% by wt.; E) from 25 to 60% by wt. 26. In electrolytic production Al with Tmelting = 938 ºC eutectic is obtained when the content of cryolite in the melt is equal to: A) ≈15% by wt.;
B) 35% by wt.; C) 45% by wt.; D) from 20 to 40% by wt.; E) > 50% by wt. 27. In electrolytic production Al with Tmelting = 938 ºC eutectic is obtained when the content of cryolite in the melt is equal to: A) 35% by wt.; B) 50% by wt.; C) 15% by wt.; D) from 18 to 38% by wt.; E) < 65% by wt. 28. In the production of aluminum, secondary processes of cryolite-alumina melt electrolysis are: A) at the anode: C O 2 CO 2 ;
B) 2Al 2 O 3 3C 4Al 3CO 2 ; C) Al 2 O 3 3C 2Al 3CO; C O CO ; D) 2Al 2 O 3 3C 4Al 3CO 2 ; C O CO ; E) Al 2 O 3 3C 2Al 3CO; 2Al 2 O 3 3C 4Al 3CO 2 . 29. In the production of aluminum, secondary processes of cryolite-alumina melt electrolysis are: A) at the anode: C + O2 = CO; B) Al 2 O 3 3C 2Al 3CO;
C) 2Al 2 O 3 3C 4Al 3CO 2 ; D) Al 2 O 3 3C 2Al 3CO ; C O CO ; E) 2Al2 O3 3C 4Al 3CO2 ; C O CO . 30. In the production of aluminum, secondary processes of cryolite-alumina melt electrolysis are: A) Al 2 O 3 3C 2Al 3CO; C O CO;
B) Al 2 O 3 3C 2Al 3CO; C) 2Al 2 O 3 3C 4Al 3CO 2 ; D) oxidation of carbon electrodes to form CO and СО2; E) Al 2 O 3 3C 2Al 3CO; 2Al 2 O 3 3C 4Al 3CO 2 . 31. Processes of electrolysis of cryolyte-alumina melt in aluminium production: A) at the anode: C + O = CO; B) at the anode: C + O2 = CO2;
C) oxidation of carbon electrodes to form CO and СО2; D) Al2O3 + 3C = 2Al + 3CO; E) 2Al2O3 + 3C = 4Al + 3CO2, C + O = CO. 32. Processes of electrolysis of cryolyte-alumina melt in aluminium production: A) at the anode: C + O = CO; B) at the anode: C + O2 = CO2; C) oxidation of carbon electrodes to form CO and СО2; D) 2Al2O3 + 3C = 4Al + 3CO2; E) Al2O3 + 3C = 2Al + 3CO. 33. Processes of electrolysis of cryolyte-alumina melt in aluminium production: A) at the anode: C + O = CO; B) at the anode: C + O2 = CO2; C) oxidation of carbon electrodes to form CO and СО2; D) 2Al2O3 + 3C = 4Al + 3CO2, C + O = CO; E) Al2O3 + 3C = 2Al + 3CO, 2Al2O3 + 3C = 4Al + 3CO2. 34. Types of anodes for electrolytic aluminium production: A) previously burned; B) self-restoring; C) self-regenerated; D) self-reducing and self-regenerating; E) periodic action. 35. Types of anodes for the electrolytic production of aluminum: A) periodic; B) semi-continuous; C) a self-reducible; D) self-firing; E) self-regenerating. 36. Types of anodes for the electrolytic production of aluminum: A) self-reducible; B) self-firing and pre-fired; C) self-regenerating; D) a self-recovering and self-regenerating; E) periodic action. 37. Cast aluminum alloys are: A) bauxite; B) appatites; C) argelites; D) silumins; E) alumina.
38. Aluminum alloys are divided into: A) crystalline and amorphous; B) granular and lumpy; C) molding and foundry; D) deformable and foundry; E) corrosive and non-corrosive. 39. Aluminum alloys – silumins contain alloying additives of silicon in the amount of: A) more than 1%; B) 1-3%; C) up to 0.5%; D) up to 13%; E) more than 13%. 40. Aluminum refining is carried out with the aim of: A) increasing the yield of the main product; B) purification from impurities and dissolved gas; C) imparting a crystalline structure; D) improving the ductility of the metal; E) eliminate the fragility of the metal.
ANSWERS TO TEST TASKS 1. INTRODUCTION TO GENERAL CHEMICAL TECHNOLOGY 1.1. GENERAL QUESTIONS OF CHEMICAL TECHNOLOGY
1-B 11-A 21-B 31-A 41-A
2-B 12-D 22-C 32-E 42-B
3-E 13-A 23-A 33-E 43-E
4-B 14-A 24-B 34-A 44-A
5-C 15-D 25-C 35-A 45-B
6-A 16-A 26-C 36-A 46-E
7-D 17-C 27-C 37-D 47-B
8-C 18-A 28-A 38-D 48-B
9-A 19-C 29-A 39-A 49-E
10-D 20-B 30-B 40-C 50-E
9-D 19-B 29-A 39-D 49-A 59-B 69-A 79-A 89-A
10-D 20-A 30-D 40-A 50-A 60-C 70-C 80-D 90-А
1.2. BASIC REGULARITIES AND METHODS OF CHEMICAL TECHNOLOGY
1-E 11-C 21-B 31-B 41-B 51-A 61-B 71-E 81-C
2-C 12-A 22-A 32-B 42-A 52-A 62-C 72-A 82-D
3-C 13-A 23-B 33-C 43-D 53-C 63-A 73-B 83-E
4-E 14-B 24-A 34-C 44-C 54-B 64-D 74-A 84-D
5-B 15-C 25-C 35-A 45-A 55-C 65-C 75-C 85-D
6-E 16-C 26-C 36-B 46-B 56-A 66-A 76-E 86-A
7-A 17-C 27-C 37-A 47-C 57-C 67-A 77-D 87-A
8-B 18-B 28-B 38-А 48-A 58-D 68-C 78-B 88-A
1.3. RAW MATERIALS, WATER, ENERGY IN CHEMICAL INDUSTRY
1-С 11-C 21-C 31-A 41-E 51-A 61-D 71-A 81-A 91-B
2-B 12-A 22-C 32-A 42-C 52-C 62-B 72-D 82-D 92-D
3-A 13-A 23-A 33-A 43-C 53-B 63-B 73-A 83-A 93-A
4-C 14-E 24-D 34-C 44-A 54-A 64-C 74-A 84-A 94-A
5-A 15-D 25-C 35-A 45-E 55-A 65-A 75-A 85-D 95-A
6-C 16-E 26-E 36-A 46-E 56-A 66-C 76-E 86-A 96-A
7-A 17-E 27-A 37-C 47-E 57-C 67-E 77-A 87-A 97-C
8-A 18-A 28-A 38-B 48-A 58-D 68-A 78-B 88-D 98-D
9-A 19-A 29-D 39-A 49-A 59-A 69-C 79-B 89-A 99-C
10-E 20-C 30-A 40-C 50-D 60-C 70-A 80-B 90-A 100-B
9-A 19-E 29-D 39-C
10-E 20-E 30-D 40-A
2. MAIN CHEMICAL PRODUCTION 2.1. SULFURIC ACID PRODUCTION
1-A 11-E 21-C 31-A
2-E 12-C 22-A 32-D
3-C 13-D 23-E 33-E
4-D 14-D 24-C 34-D
5-E 15-A 25-D 35-A
6-C 16-D 26-B 36-E
7-A 17-A 27-A 37-E
8-B 18-C 28-C 38-D
41-D 51-A 61-D 71-E 81-A 91-D
42-A 52-D 62-C 72-D 82-A 92-E
43-B 53-C 63-D 73-C 83-D 93-A
44-C 54-E 64-E 74-C 84-C 94-E
45-C 55-A 65-C 75-C 85-A 95-E
46-C 56-E 66-A 76-A 86-C 96-B
47-B 57-B 67-A 77-A 87-E 97-C
48-E 58-D 68-A 78-C 88-E 98-D
49-D 59-A 69-A 79-D 89C 99-A
50-E 60-C 70-C 80-C 90-E 100-C
2.2. TECHNOLOGY OF FIXED NITROGEN
1-D 11-D 21-D 31-A 41-D 51-C
2-C 12-A 22-A 32-A 42-B 52-D
3-D 13-C 23-D 33-A 43-A 53-C
4-A 14-E 24-A 34-C 44-D 54-C
5-A 15-C 25-D 35-E 45-A 55-B
6-A 16-D 26-D 36-C 46-B 56-B
7-C 17-A 27-A 37-A 47-B 57-C
8-A 18-E 28-C 38-A 48-A 58-A
9-A 19-A 29-D 39-B 49-C 59-C
10-D 20-A 30-E 40-C 50-E 60-A
2.3. TECHNOLOGY OF SALTS AND FERTILIZERS
1-C 11-A 21-C 31-C 41-D 51-A 61-B
2-C 12-D 22-D 32-A 42-C 52-C 62-D
3-C 13-E 23-B 33-C 43-B 53-C 63-D
4-D 14-C 24-A 34-D 44-C 54-D 64-A
5-B 15-C 25-C 35-C 45-A 55-A 65-B
6-A 16-C 26-A 36-D 46-A 56-D 66-A
7-D 17-D 27-A 37-B 47-D 57-D 67-A
8-D 18-C 28-A 38-C 48-D 58-D 68-C
9-D 19-A 29-C 39-D 49-E 59-B 69-C
10-B 20-A 30-A 40-C 50-E 60-D 70-C
2.4. PRODUCTION OF PHOSPHORUS AND PHOSPHORIC ACIDS
1-E 11-E 21-A 31B 41-B
2-A 12-D 22-C 32-C 42-A
3-D 13-A 23-B 33-A 43-A
4-C 14-B 24-E 34-A 44-A
5-C 15-C 25-A 35-C 45-A
6C 16-A 26-D 36-D 46-A
7-D 17-C 27-A 37-C 47-E
8-B 18-E 28-A 38-D 48-E
9-A 19-E 29-A 39-C 49-A
10-D 20-B 30-A 40-C 50-C
9-D 19-A 29-D 39-C 49-A
10-C 20-D 30-C 40-A 50-A
2.5 CATALYSIS IN CHEMICAL PRODUCTION
1-B 11-E 21-B 31-D 41-A
2-D 12-A 22-C 32-E 42-E
3-A 13-D 23-A 33-B 43-A
4-E 14-E 24-B 34-D 44-A
5-B 15-D 25-A 35-C 45-D
6-D 16-D 26-A 36-D 46-D
7-D 17-D 27-A 37-C 47-A
8-B 18-D 28-A 38-D 48-D
2.6. PRODUCTION OF HYDROCHLORIC ACID, CHLORINE AND ALKALI
1-С 11-D 21-E 31-B
2-B 12-D 22-C 32-C
3-D 13-B 23-D 33-C
4-A 14-D 24-D 34_B
5-A 15-D 25-A 35-A
6-A 16-C 26-A 36-B
7-D 17-D 27-B 37-B
8-C 18-E 28-A 38-A
9-E 19-E 29-D 39-A
10-D 20-D 30-C 40-B
8-D 18-D 28-C 38-B
9-D 19-D 29-D 39-B
10-A 20-C 30-B 40-B
8-E 18-C 28-A 38-D
9-D 19-A 29-A 39-D
10-C 20-A 30-D 40-B
2.7. PRODUCTION OF SODA PRODUCTS
1-D 11-A 21-C 31-D
2-C 12-D 22-E 32-B
3-A 13-B 23-D 33-D
4-B 14-D 24-C 34-A
5-D 15-E 25-D 35-C
6-E 16-D 26-C 36-C
7-D 17-A 27-B 37-A
2.8. ALUMINUM PRODUCTION
1-A 11-A 21-B 31-D
2-B 12-A 22-E 32-D
3-B 13-C 23-A 33-E
4-A 14-A 24-A 34-A
5-D 15-D 25-B 35-D
6-A 16-C 26-A 36-B
7-C 17-A 27-C 37-D
GLOSSARY A Absolute humidity of the gas is the amount of water vapor in the unit volume or mass of the gas (g/m3 or g/kg). Accident is a dangerous technogenic event creating at the site, territory or waters a threat to life and health of people and leading to the destruction of buildings, equipment and vehicles, disruption of production or transport process, as well as damage to the environment. Accidents are events that occur unintentionally or are unexpected, unwanted, unforeseen, and cause damage, injury, etc. Accidents can result in pollutant discharges and physical effects on the environment (e.g., fire and explosions), which are neither expected nor allowed during the course of normal industrial operations. The basic differences between accidents and routine operations, in terms of their potential pressures on the environment and human populations, are characterized by the following general parameters: the toxicity of discharges, the volume and rate of the release, and flammability and explosiveness. Good planning, management and control of the routine activities is necessary to prevent accidents. Accidental pollution is an unexpected occurrence, losses at a plant or on a transportation route, resulting in a release of a potentially polluting material. ACEA (European Automobile Manufacturers Association) is an organization that develops and monitors the use of quality standards for lubricants for automotive engines in Europe. Acid-base catalysis is a catalytic reaction, where acids or bases are involved as catalysts. In general, this term can refer to both Brönsted and Lewis acids and bases. However, more specific terms for electrophilic and nucleophilic catalysis are also used for Lewis acids and bases. In the case of Brönsted acids and bases, the specific and general acid-base catalyses are distinguished, which are determined by the specific features of the mechanism of the catalytic process. Acidic center is grouping of atoms in the structure of a macromolecule or on the surface of a solid body, which is capable of attaching a base with transferring it to a conjugate acid. Acidity is the ability of a substance to interact with a base. In this case, the base passes into the conjugate acid. The Act legal (statutory) on protection of the (person) environment is the international or government decision (the convention, the agreement, the pact, the law, the resolution), decisions of local public authorities, the departmental instructtion, etc. regulating legal relationship or setting restrictions in the field of protection of the environment surrounding the person. The activation energy, for an elementary chemical transformation, is the minimum energy of the reagents, sufficient to overcome the barrier at the surface of the potential energy that separates the reactants from the products. If the reaction is complex (consisting of several stages), this term usually indicates an effective (apparent) activation energy.
Activation of the catalyst is a technological stage which prepares the catalyst for work with a reactionary mixture. In some cases it is convenient to carry out activation of the catalyst after its loading into the reactor. At a stage of activation there is a final formation of necessary phase structure of the catalyst including, for example, reduction, sulfonation, oxidation, dehydroxylation (removal of water), addition of the activator and other processes. Activation of chemical reactions is a phenomenon of increasing the rates of chemical reactions in the presence of acids or bases, accompanied by their consumption. Such processes are sometimes called pseudo-catalytic processes. For such reactions, the mechanism of intermediate reaction of the reactants with the acid or base is similar to the true catalytic reaction, however, catalyst regeneration does not occur at the end of the catalytic cycle. Example: the hydrolysis of carboxylic acid esters is accelerated in the presence of acid and represents a true catalytic reaction. The hydrolysis of amides of carboxylic acids should be considered as a pseudo-catalytic reaction, since it is also accelerated in the presence of an acid, but at the end of the catalytic cycle, an ammonium ion is formed instead of H+. Activator is a substance which interacts with the catalyst and causes an increase in the speed of the catalytic reaction, but itself isn't spent. For example, the rate of polymerization of α-olefins on metallocene catalysts increases significantly when methylaluminoxane is added to the system. Active phase – this term has the same meaning as the active component. It is used in those cases when it is required to specify the phase composition of the active component under catalytic process conditions. Example: the melt of potassium pyrosulfonadate is the active phase in the vanadium catalyst for the oxidation of SO2 into SO3. Active component is the substance which is a component of the multicomponent catalyst and direct catalytic transformation. Other components of the catalyst perform support functions, for example, are the carrier or the promotor. Example: for the (deposited) catalyst of hydrogenation Ni/SiO2, an active component is metal nickel, while silicon oxide is the carrier. Additives are chemicals added to petroleum products in small amounts to improve quality or add special characteristics. They are non-hydrocarbon compounds added to or blended with a product to modify fuel properties (octane, cetane, cold properties, etc.). Examples: oxygenates: alcohols (methanol, ethanol), ethers such as MTBE (methyl tertiary butyl ether), ETBE (ethyl tertiary butyl ether), TAME (tertiary amyl methyl ether); esters (for example, rapeseed or dimethyl ether, etc.); chemical compounds (tetramethyl lead, tetraethyl lead and detergents). It must be remembered that the quantities of ethanol listed in this category should refer to amounts intended for fuel use. Adhesion coefficient is the ratio of the number of adsorbed molecules per a unit of time to the frequency of concussions of molecules with the surface of adsorbent. The coefficient of adhesion depends on the filling factor of the surface, temperature, structure of the surface of the adsorbent and other parameters. Adhesive lubricants are lubricants with components that improve adhesion, which do not break from the surfaces by centrifugal forces.
Agglomerates are particles of matter obtained by combining smaller particles, for example, associates from primary particles. The aggregate state of a substance is a state of a substance characterized by certain qualitative properties: the ability or inability to maintain volume and shape, and the presence or absence of a far and near order. Changes in the aggregate state can be accompanied by abrupt changes in free energy, entropy, density, and other basic physical properties. In terrestrial conditions, a substance can be in four aggregate states: solid, liquid, gas, and plasma. Aging of the catalyst is a slow and irreversible decrease in the catalytic activity as a result of changes in the structure of the catalyst. Afterburn is the combustion of carbon monoxide (CO) to carbon dioxide (CO,); usually in the cyclones of a catalyst regenerator. Aftertreatment system is a system that treats post-combustion exhaust gases prior to tailpipe emission. It differs from emission reduction techniques in the combustion process and allows for greater power from the engine without worrying about increasing emissions. Air is a physical mixture of gases that make up the atmosphere of the Earth, the most important ecological product. From the air plants draw carbon dioxide for photosynthesis, the vast majority of organisms – oxygen for breathing, biological nitrogen fixers – nitrogen. At the surface of the earth, dry and clean air contains 78.9% of nitrogen, 20.95% of oxygen, and 0.03% of carbon dioxide. Other gases account for less than 0.01%. Due to intensive mixing, the air composition in the horizontal and vertical direction up to a height of 80-100 km is constant. Air fin coolers is a radiator-like device used to cool or condense hot hydrocarbons. Air emissions are any substances (gases and particulate matter) emitted into the air from industrial processes or from households, such as carbon monoxide, nitrogen oxide, nitrogen dioxide, sulphur dioxide or any other mixture of particulates and air that are airborne. In many countries, emissions are regulated by countrywide emission standards. These can be either related to specific industries or to general emissions regulations. Air indoors is an atmospheric air, warmed (cooled) and partially filtered through wall coverings and glazed window openings. It is close in composition to the air of populated areas, but it has a higher content of carbon dioxide, lower oxygen and, usually, higher radioactivity, especially in houses of certain types of concrete and silica brick and in the presence of granites in the foundations. To maintain the normal air composition in such houses, the speed of its movement is about 0.1 m/s. The best material for the walls is wood. Heating systems and kitchens, especially with gas stoves, have an important influence on the air quality of the rooms. Air pollutant is any substance in air that in high enough concentration could harm man, animals, vegetation, or material. Pollutants may include almost any natural or artificial composition of airborne matter capable of being airborne. They may be in the form of solid particles, liquid droplets, gases, or in combination thereof. Generally, they may be: 1) emitted directly from identifiable sources, 2) produced in the air by interaction between two or more primary pollutants, or by reaction with normal atmospheric constituents, with or without photo activation.
Air pollution is the discharge of toxic gases and particulate matter into the atmosphere, mainly, as a result of human activity. Air quality index is a general air pollution index freely available to the public in major West European cities. This daily index, rated from 1 (excellent) to 10 (extremely polluted), takes into account ozone, sulphur dioxide and nitrogen dioxide levels, all of which are toxic for human health and are regulated at the European level. The concentrations close to the warning limit correspond to an index of 4 to 5. However, this daily index, which does give a general idea of the air quality, does not reveal which substance is causing the pollution. A traffic index characterizes the air quality in a dense traffic environment, taking into account the pollutants typical for traffic, nitrogen oxides and carbon monoxide. Any index greater than 6 corresponds to an abnormal situation, index 7 to strong air pollution caused by traffic, and the indices 8, 9 and 10 to increasingly heavy pollution up to an exceptionally high level. Air sweetening is a process in which air or oxygen is used to oxidize lead mercaptides to disulfides instead of using elemental sulfur. Alicyclic hydrocarbon is a compound containing carbon and hydrogen only, which has a cyclic structure (e.g., cyclohexane); also collectively called naphthenes. Aliphatic hydrocarbon is a compound containing carbon and hydrogen only, which has an open-chain structure (e.g., ethane, butane, octane, butene) or a cyclic structure (e.g., cyclohexane). Alkanes (paraffins, saturated hydrocarbons) are a homologous series of noncyclic hydrocarbons that do not contain double or triple bonds. The simplest alkane is methane, the subsequent terms of the series (propane, butane, pentane, etc.) are obtained by adding to one ethylene one carbon atom – a methyl group. The general formula for the series is CnH2n+2. Alkenes (unsaturated hydrocarbons, olefins) is a homologous series of noncyclic hydrocarbons containing double bonds. The simplest member of the series – ethylene contains two carbon atoms. It is followed by propylene, butylenes, etc. The general formula for the series is CnH2n. Alternative fuels are fuel types (compressed and liquefied gas, biogas, generator gas, biomass processing products, water-coal fuel, etc.), the use of which reduces or replaces the consumption of energy resources of more expensive and scarce species. Alumina (A12O3) is an oxide of aluminium used in separation methods as an adsorbent and in refining as a catalyst. Aniline point is the temperature, usually expressed in ºF, above which equal volumes of a petroleum product are completely miscible; a qualitative indication of the relative proportions of paraffins in a petroleum product which are miscible with aniline only at higher temperatures; a high aniline point indicates low aromatics. Anode is an electrode in electrochemical devices (galvanic cells, batteries, electrolyzers), on which the oxidation process takes place. Anode coating is a method of protecting iron and other metals from corrosion by electrolytic deposition of a thin film of another metal (Cr, Ni, Cd, Zn, Al, Sn) on the surface. The product to be protected during coating is the cathode, and the deposited metal is the anode. During electrolysis, metal is transferred from the anode to the cathode.
Anodizing is the electrochemical oxidation of the surface of products made of aluminum, chromium and other metals. The product is placed in the electrolyzer as an anode, and the electrolyte is sulfuric, chromic or oxalic acid. The metal is oxidized by the oxygen released on it. Anodizing of metals is used to decorate products, protect against corrosion, increase the coefficient of reflection of light, impart electrical insulation properties, etc. Antiknock is resistance to detonation or pinging in spark-ignition engines. Antiknock agent is a chemical compound such as tetraethyl lead which, when added in a small amount to the fuel charge of an internal-combustion engine, tends to reduce knocking. Antistripping agent is an additive used in an asphaltic binder to overcome the natural affinity of an aggregate for water instead of asphalt. Anthropogenic landscape is the natural landscape transformed by human activity. Anthropogenous pollution is pollution resulting from people’s activities, including their direct or indirect impact on the intensity of natural pollution. Anthropogenic factor is an environmental factor associated with human exposure to the environment: pollution, depletion of resources, reduction of animal and plant species. API Gravity is an arbitrary scale expressing the density of petroleum products. Apparent density is the density of a solid porous substance, which is calculated as the ratio of the mass of the particle to its volume. Since part of this volume falls on the pores inside the particle, the apparent density of the porous substance is less than its true density. Aromatic hydrocarbons are organic compounds containing a cycle with conjugated double bonds in their structure. In the petrochemical industry, this name usually involves benzene, toluene and xylenes (ortho-, meta- and para-). Aromatics are organic compounds with one or more benzene rings. Aromatization is the conversion of nonaromatic hydrocarbons into aromatic hydrocarbons by: (1) rearrangement of aliphatic (noncyclic) hydrocarbons into aromatic ring structures; (2) dehydrogenation of alicyclic hydrocarbons (naphthenes). ART process is a process for increasing the production of liquid fuels without hydrocracking. Asphalt is a nonvolatile product obtained by distillation and treatment of an asphaltic crude oil with liquid propane or liquid butane; usually consists of asphalttenes, resins, and gas oil; a manufactured product. Asphaltene is a fraction of petroleum, heavy oil, or bitumen that is precipitated when a large excess (40 volumes) of a low-boiling liquid hydrocarbon (e.g., pentane or heptane) is added to (1 volume) of the feedstock; usually a dark brown to black amorphous solid that does not melt prior to decomposition and is soluble in benzene or aromatic naphtha or other chlorinated hydrocarbon solvents.
Asphaltenes are the asphalt compounds soluble in carbon disulfide but insoluble in paraffin naphthas. They are the most high-molecular components of oil. Associated petroleum gas, APG is an oil product. In reservoir conditions, it is dissolved in oil and released when the fossil is extracted to the surface. The composition of associated gas varies greatly, but its main component is methane, as well as a certain amount of ethane, pentane and butanes, etc. ATF liquid is a special gear oil that has a liquid consistency and has a mineral or synthetic base. It is intended for cars operating on «automation». ATF transmission fluid is responsible for performing many functions, for example: smooth operation of the gearbox – its control and management; cooling and proper lubrication of parts that can be rubbed; transmission of torque, which through the torque converter passes from the motor to the box; friction disco operation Atmosphere is a gaseous shell of the Earth, held by gravity and taking part in its rotation, consisting of a mixture of different gases, extending for approximately 100 km (there is no strict upper boundary of the atmosphere). Dry atmospheric air consists of nitrogen (78.09%), oxygen (20.93%), argon (0.93%), carbon dioxide (0.03%), hydrogen, helium and other gases. The modern atmosphere is largely the result of activity of living matter. Complete renewal of oxygen by living matter takes place over 5,200-5,800 years. All its mass is assimilated by living organisms for 2,000 years, all СО2 – for 300-400 years. Under the influence of economic human activity negative changes occur in the atmosphere – an increase in the amount of greenhouse gases, the destruction of the ozone layer. This leads to negative consequences for the biosphere (warming of the climate, acid rains, etc.). Atmospheric air is a vital component of the natural environment, which is a natural mixture of atmospheric gases outside the residential, industrial and other premises. Audit of environmental management systems is a systematic and documentted process for verifying objectively obtained and evaluated audit data to determine whether an organization's environmental management system (or nonconformity) is in compliance with the audit criteria for such a system, and to communicate the results obtained during this process to the client. Auditor in the field of ecology (auditor-ecologist) is a person having the appropriate qualifications and a certificate for conducting environmental audits. Aviation gasoline is any of the special grades of gasoline suitable for use in certain airplane engines. It is motor spirit prepared especially for aviation piston engines, with an octane number suited to the engine, a freezing point of –60 °C and a distillation range usually within the limits of 30 C and 180 °C. B Barrel is the unit of measurement of liquids in the petroleum industry; equivalent to 42 U.S. standard gallons or 33.6 imperial gallons. It is a unit of measure for volume equal to ≈ 159 l. Barium complex, lubrication is a grease based on barium complex and mineral and/or synthetic base oils, has the property of watertightness and good shear stability, often has a narrow operating temperature range.
Base oils are light oil products or synthetic hydrocarbons, used together with additives for production of lubricating oils – motor and transmission oils and ATF liquids. Battery is a series of stills or other refinery equipment operated as a unit. Batteries (drives) are chemical sources of current that can repeatedly accumulate electrical energy and give it away for consumption. Unlike galvanic cells, batteries are secondary chemical current sources. Battery electrodes immersed in an electrolyte solution, when electric energy is supplied, acquire different potentials (battery charging), and when electricity is consumed, the electrode potentials decrease (battery discharge). The most widely used are lead and cadmium-nickel batteries. Bauxite (French: bauxite), named after Baux in the south of France, is an aluminum ore consisting of aluminum hydroxide, iron oxides and silicon. These are raw materials for producing alumina and alumina-containing refractories. The alumina content in industrial bauxite ranges from 40 to 60% and higher. It is also used as a flux in the steel industry. Bentonite is montmorillonite (a magnesium-aluminum silicate); used as a treating agent. Benzo(a)pyrene is a compound from the group of polycyclic aromatic hydrocarbons, a widely spread carcinogen substance. It is present in gaseous industrial wastes, in automobile exhausts, in tobacco smoke, in food combustion products. Ferrous metallurgy accounts for up to 40%, heat-power engineering –26%, the chemical industry – 16% of benzene(a)pyrene, supplied to the environment. Benzene is an unsaturated, colorless, six-carbon ring, basic aromatic liquid compound (C6H6). Berthollet’s salt is potassium chlorate KClO3. It was first obtained by K. Bertollet in 1786 by passing chlorine through a hot concentrated solution of potassium hydroxide:
6KOH + 3Cl2 = KClO3 + 5KCl + 3H2O. Mixtures of potassium chlorate with reducing agents (phosphorus, sulfur, organic compounds) are explosive and sensitive to friction and shock; used in pyrotechnic products. BET is the method of determination of specific surface area of solid bodies based on the model of physical adsorption of molecules of gases (nitrogen, argon, etc.) using the accepted value of molecular cross section. The method has received the name by the names of three scientists (S. Brunauer, P. Emmett, E. Teller), who developed the corresponding model for polymolecular adsorption. Despite some shortcomings in the theoretical description, this method is widely used as a standard technique for determining the surface area of catalysts and adsorbents. Binary compounds (borides, halides, hydrides, carbides, oxides, pnictogenides, silicides, chalcogenides) are chemicals formed, as a rule, by two chemical elements. The term «binary compounds» is usually not applied to basic and acid oxides. Non-salt forming oxides are included in binary compounds. Bitumen is a solid, semi-solid or viscous hydrocarbon with a colloidal structure, brown to black in colour, obtained as a residue in the distillation of crude oil, by vacuum distillation of oil residues from atmospheric distillation. Bitumen is often referred to as asphalt and is primarily used for construction of roads and as roofing material. This category includes fluidised and cut back bitumen.
Bituminous is containing bitumen or constituting the source of bitumen. Bituminous sand is a formation in which the bituminous material (see Bitumen) is found as a filling in veins and fissures in fractured rocks or impregnating relatively shallow sand, sandstone, and limestone strata; a sandstone reservoir that is impregnated with a heavy, viscous black petroleum-like material that cannot be retrieved through a well by conventional production techniques. Blending is the process of mixing two or more petroleum products with different properties to produce a finished product with desired characteristics. A block (honeycomb) catalyst is a heterogeneous catalyst in which a carrier is used in the form of a monolithic block. Usually the block has a set of parallel not crossed channels and is manufactured of ceramic silicate or metal materials. The active component is applied to the surface of the channels. The block catalyst is used in such processes where a large pressure drop is undesirable, for example, in the neutralization of exhaust gases in automobiles. Boiling range is the range of temperatures usually determined at atmospheric pressure in standard laboratory over which boiling (or distillation) of a hydrocarbon liquid commences, proceeds, and finishes. Borax is a natural compound (mineral), the chemical formula of Na2B4O7 · · 10H2O is sodium tetraborate. It is used for soldering metals as a flux, in the production of enamels, glazes, optical and non-colored glasses, in the paper and phar-maceutical industries, etc. Broad (wide) fraction of light hydrocarbons (BFLH or WFLH) is a product of processing of associated petroleum or natural gas. It is a mixture of volatile hydrocarbons with a number of carbon atoms from 2 to 5 and valuable petrochemical raw materials. Bronze is an alloy of copper with various metals (tin, aluminum, beryllium, lead, cadmium, chromium, etc.). Accordingly, bronze is called tin, aluminum, beryllium, etc. Buffer solutions (from English buff – to soften blow) are solutions with a certain steady concentration of hydrogen ions; it is a mixture of a weak acid and its salt (for example, CH3COOH and CH3COONa) or a weak base and its salt (for example, NH3 and NH4CI). The pH of the buffer solution changes little when small amounts of acid or alkali are added, when diluted or concentrated. Buffer solutions are widely used in various chemical research, they are of great importance for the processes in living organisms. A large number of buffer solutions are known (acetate-ammonia, phosphate, borate, formate, etc.). Bulk density is the density of a solid-phase material calculated as a ratio of the mass of the sample to the volume occupied by the sample. At the same time, the volume considers the free space which is available in particles and between particles. Thus, bulk density depends both on porosity of individual particles, and on the density of their packing, which in turn depends on the geometrical form of particles (powder, granules, tablets, etc.). Butane dehydrogenation is a process of removing hydrogen from butane to produce butenes and, on occasion, butadiene. Butane vapor-phase isomerization is a process for isomerizing n-butane to isobutene using aluminum chloride catalyst on a granular alumina support and with hydrogen chloride as a promoter.
Butane-butylene fraction (BBP) is a gaseous product of a catalytic cracking process containing normal (unbranched) alkanes and alkenes with 4 carbon atoms. By-product is a substance that is formed during the processing of raw materials along with the target product, but is not the goal of this production. Byproducts resulting from the production or enrichment of raw materials, are called coproducts (passing products). C The calorie equivalent characterizes the energy value of a chemical fuel and represents the ratio of the net calorific value of a given fuel to the calorific value of conventional fuel (CF), taken as 29,260 kJ: ɳc = Qn/29,260 C1, C2, C3, C4, C5 fractions are a common way of representing fractions containing a preponderance of hydrocarbons having 1, 2, 3, 4, or 5 carbon atoms, respectively, and without reference to hydrocarbon type. Capital expenditures are the sum of all costs incurred in the construction of a workshop or an enterprise as a whole. They include the cost of purchasing equipment, machinery and equipment (the active part) and construction and installation work (the passive part). The efficiency of return on capital expenditures depends on the share of their active part and is estimated by the criterion «specific capital expenditures», that is, the cost per unit of output A car is a common vehicle, the most important factor in the formation of an urbanized territory. The number of cars, especially in megacities, is very large and growing. Carbene is the pentane- or heptane-insoluble material that is insoluble in benzene or toluene but soluble in carbon disulfide (or pyridine); a type of rifle used for hunting bison. Carboid is the pentane- or heptane-insoluble material that is insoluble in benzene or toluene and also insoluble in carbon disulfide (or pyridine). Carbon residue is the amount of carbonaceous residue remaining after thermal decomposition of petroleum, a petroleum fraction, or a petroleum product in a limited amount of air; also called the coke- or carbon-forming propensity. Carbonate washing is processing using a mild alkali (e.g., potassium carbonate) process for emission control by the removal of acid gases from gas streams. Carbonization is formation of coke on the surface of heterogeneous catalysts. Deposits of coke block the surface of the catalyst therefore its activity can significantly decrease and change selectivity of the catalyst. It is one of the main reasons for the deactivation of catalysts used in refining processes (cracking, reforming, dehydrogenation, etc.). It is the removal of all lighter distillable hydrocarbons that leave a residue of carbon in the bottom of units or as buildup or deposits on equipment and catalysts. Carrier is a solid phase component in the deposited (supported) catalyst, on the surface of which the active component is located. The main functions of the
carrier are maintenance of an active component in a disperse state, creation of a porous system, ensuring mechanical durability of granules of the catalyst. Simple and complex oxides, and also materials on the basis of carbon are widely used as carriers. As a rule, the carrier in pure form doesn't show catalytic activity in relation to reagents and is an inert substance. But many examples when the carrier enters into chemical interaction with the reactionary medium, or with an active component are known. Catalysis is the phenomenon of initiation of chemical reactions or change of their speed under the influence of substances – catalysts, which repeatedly enter into intermediate chemical interaction with the participants of the reaction and restore the structure after each cycle of intermediate interactions. At the same time, the catalyst doesn't displace chemical balance of reactions. Catalyst is a substance that changes the rate of chemical reactions without shifting their chemical equilibrium, which repeatedly enters into an intermediate chemical interaction with reagents and regenerates its chemical composition after each cycle of such interactions. An important feature is that the catalyst is regenerated in each catalytic cycle, which allows conversion of large amounts of reagents in the presence of a relatively small amount of catalyst. As a rule, for each chemical reaction it is required to select a specific catalyst. Practical application as catalysts is found by extremely different substances – from solutions of acids and complexes of metals to complex solid-phase multicomponent compounds of strictly specified composition and structure. Catalyst durability is ability of particles of the solid-phase catalyst to maintain mechanical loadings. There are various experimental techniques for determination of durability (for example, durability on attrition, durability on crush). For commercial catalysts high durability allows us to minimize losses during catalytic process, as well as during transportation the catalyst and its loading in the reactor. Catalyst plugging is deposition of carbon (coke) or metal contaminants that decreases flow through the catalyst bed. Catalyst poisoning is deposition of carbon (coke) or metal contaminants that makes the catalyst nonfunctional. Catalyst selectivity is a relative activity of the catalyst with respect to a particular compound in a mixture, or the relative rate in competing reactions of a single reactant. Catalyst poisoning is a partial or complete loss of its activity under the influence of an insignificant amount of some substances – contact poisons. Contact poisons form surface chemical compounds with activated catalyst centers and block them, reducing the activity of the catalyst. For each group of catalysts, there are certain types of contact poisons. Catalyst poisoning can be reversible when contact poisons decrease the activity of the catalyst temporarily while they are in the catalysis zone, and irreversible when catalyst activity is not restored after contact poisons are removed from the catalysis zone. Contact poisons can be contained in the reagents entering the catalytic process, and can also be formed as by-products in the process itself. Catalyst productivity is the amount of product produced per unit time, referred to the mass or volume of the catalyst.
Catalyst stripping is the introduction of steam, at a point where spent catalyst leaves the reactor, in order to strip, i.e., remove deposits retained on the catalyst. Catalytic activity is the rate of a chemical reaction, referred to the number of active catalyst centers or to a unit of mass or volume of the catalyst. The activity of the catalyst is determined by the nature and strength of the chemical bonds that are formed when reactants and reaction intermediates are bound to the catalyst. For a correct measurement of the catalytic activity it is necessary to exclude the impact of mass and heat transfer. The catalytic center is the center in which catalytic chemical transformations occur. If the number of the catalytic centers is unknown, for example, in case of a heterogeneous photocatalysis, for determination of specific parameters BET surface measured on nitrogen adsorption is used. Catalytic combustion is a technology developed to produce thermal energy by oxidizing combustible compounds with oxygen in the presence of a catalyst. In the presence of catalysts, oxidation occurs at lower temperatures (without open flame). Multicomponent catalysts containing Cu, Cr, Pd, Mn and other components are used. Catalytic combustion is used in catalytic heat generators (CHG). The catalytic converter (neutralizer) of exhaust gases of the car engine is a device for neutralization of the exhaust gases of the car engine by the method of catalytic action. It is a catalyst that provides removal of a number of harmful substances from the exhaust gases in the internal combustion engines. The main catalytic processes are oxidation of CO, post-combustion of hydrocarbons to CO2 and reduction of nitrogen oxides. The most suitable are noble metal catalysts (Pt). The neutralization process is complicated due to temperature fluctuations in the exhaust gases (from 200 to 1,000°C) and changes in the composition of the gas mixture (from oxidizing with excess oxygen to reducing with oxygen deficiency). Catalytic cracking is a secondary process of oil refining (process of conversion), which consists in splitting of long hydrocarbonic molecules into shorter ones. It is the process of breaking up heavier hydrocarbon molecules into lighter hydrocarbon fractions by use of heat and catalysts and a source of petrochemical raw materials, such as propane-propylene fraction. Catalytic reforming is a secondary process of oil refining, the essence of which is the conversion of hydrocarbon chains into aromatic compounds – components of fuels and petrochemical raw materials. Catalytic cycle is a system of elementary reactions with participation of the catalyst at which the sequence is closed, a cyclic process of binding and regeneration of the catalyst occurs and the conversion of the starting materials to the products proceeds. An important feature is that after completion of the catalytic cycle, the catalyst passes to the initial chemical state and the catalytic cycle can be repeated many times with the same catalyst. Catalytic erosion is the destruction of the catalyst in the dendritic mechanism of coke formation. Separate components of the catalyst are mechanically separated and carried away with the growth of primary dendrites, which can lead to the complete destruction of the catalyst. The catalytic reaction is a chemical reaction proceeding through a sequence of stages forming a catalytic cycle. The catalytic route of the reaction is proved by
the fact that the catalytic cycle can be realized several times (the number of revolutions exceeds one). Currently, more than 80% of all industrial chemical processes are carried out using catalytic reactions. Catalytic poison is a substance that forms strong chemical bonds (usually covalent) with atoms and ions entering the active sites of the catalyst to form catalytically inactive centers and, thus, leads to deactivation of the catalyst. In most cases, the catalytic activity and/or selectivity cannot be restored without a significant change in the reaction conditions. Special regeneration procedures are required, and most often the characteristics can only be partially recovered. The catalytic poison may be present as an impurity in a mixture of reagents, or it may enter the catalyst during the preparation stage. Typical poisons are sulfur and arsenic compounds, and also the compounds of transition metals contained in raw materials can act as catalytic poisons. Cementing materials are substances that can harden as a result of physicochemical processes. Passing from a pasty to a stone-like state, an astringent holds together stones or grains of sand, gravel, crushed stone. This property of binders is used for the manufacture of concrete, silicate brick, asbestos cement and other unbaked artificial materials, mortars – masonry, plaster and special. Cementing materials are divided into inorganic materials (lime, cement, building gypsum, magnesia cement, water glass, etc.), which are put into working condition (shut) with water (less often with aqueous solutions of salts); organic (bitumen, tar, animal glue, polymers), which transform into working condition by heating, melting or dissolving in organic liquids. Chemical technology is the basis of chemical production. From the Greek language, the term «technology» is translated as the science of the ability to do or create (technos – art, craft; logos – science, teaching). The object of chemical technology is substances and systems of substances involved in chemical production, or chemical production itself. The processes of chemical technology are a combination of various operations carried out in the course of production in order to transform one substance into another. Chemical technology considers not only methods of chemical processing, but also a variety of physical, chemical and mechanical processes. Chemical technology studies the processing reactions that are associated with changes in the composition, structure and properties of substances, that is, with their chemical transformation into other substances. The subject of study of chemical technology is chemical production, as a method of processing starting materials (raw materials) into useful products. The purpose of the study of chemical technology is to create appropriate ways to produce the necessary human products. Chemical technology is divided by industry into two groups: inorganic and organic. The bases of creation of the foundations of chemical technology were laid back in antiquity mainly in ancient China, the states of the Ancient East, America, and later in Europe, Russia and other countries. But as an independent scientific direction, chemical technology was formed by the middle of the 20th century, although the prerequisites for this were the achievements of scientists beginning in the 8th century and the succeeding centuries. Modern chemical production begins with the invention of the French chemist Leblanc of the soda production method in 1789.
CHP is a combined heat and power plant, a system in which steam produced in a power station as a by-product of electricity generation is used to heat nearby buildings. Clark is a quantity that expresses the content of elements in the earth's crust in mass or atomic percentages, or grams per ton. Classification is the process of separating homogeneous bulk materials into fractions (classes) by the size of their constituent particles. It is carried out by sieving materials (screening), separation of the mixture of particles by the rate of their deposition in the liquid phase (hydraulic classification), separation of the mixture of particles by the rate of their deposition in the air using separators (air classification). Clay is silicate minerals that also usually contain aluminum and have particle sizes less than 0.002 micron; used in separation methods as an adsorbent and in refining as a catalyst. Clay refining is a treating process in which vaporized gasoline or other light petroleum product is passed through a bed of granular clay such as fuller’s earth. Clay regeneration is a process in which the spent coarse-grained adsorbent clays from percolation processes are cleaned for reuse by de-oiling them with naphtha, steaming out the excess naphtha, and then roasting in a stream of air to remove carbonaceous matter. Clay wash is a light oil, such as kerosene (kerosine) or naphtha, used to clean fuller’s earth after using it in a filter. The Clean Development Mechanism (CDM) is the cooperation mechanism created in the framework of the Kyoto Protocol, which opens potential opportunities for the help to developing countries in ensuring sustainable development due to support of the ecologically favorable investments of the governments and businesses of industrially developed countries. Closed pores are pores that do not communicate with the outer surface of the particle. Molecules from the surrounding space cannot penetrate into the closed pores, therefore, such pores cannot participate in adsorption and catalysis. Closed system of water management in a territorial industrial complex, district or center is a system that includes the use of surface water, treated industrial and municipal sewage in industrial plants, agricultural irrigation fields for growing crops, for watering forest lands, for maintaining the volume (level) of water reservoirs, excluding formation of any waste and discharge of sewage into the reservoir. Closed water system of an industrial enterprise is a system in which water is used in production many times without treatment or after appropriate treatment, excluding formation of any waste and discharge of waste water into the body of water. Coagulation is the process of combining (cohesion) of small particles in a dispersed system with the formation of larger particles. Example: as a result of coagulation, the sol passes into the suspension. Coalescence is the process of merging droplets or gas bubbles in disperse systems. Coke means the condensed aromatic hydrocarbons whose structure approximates to graphite. The formation of coke on the surface of catalysts is a harmful byproduct of hydrocarbon processing.
Coking is formation of coke on the surface of heterogeneous catalysts. Deposits of coke block the surface of the catalyst therefore its activity can significantly decrease and change selectivity of the catalyst. Coking is one of the main reasons for the deactivation of catalysts used in refining processes (cracking, reforming, dehydrogenation, etc.). A colloidal solution is a dispersed system occupying an intermediate position between true solutions and coarsely dispersed systems. The particles of the dispersed phase in the colloidal solution have a size from 1 to 100 nm. Combustible gases are the natural gases having ability to burn. They usually consist of gaseous hydrocarbons (methane, ethane, etc.) and are satellites of oil, although purely gas fields are also known. If combustible gas contains a significant amount of vapors of natural gasoline, such a gas is called fat, at very small content of natural gasoline, or at its absence the gas is called dry. B. Comenar’ laws can be expressed in the following laconic formulas: – everything is connected with everything (reflects the property of generality of ties); – everything has to disappear somewhere (option of conservation laws); – nature knows better (human knowledge of natural processes is limited); – nothing is given by a gift, nothing is free (the use of any resource needs to be compensated). Compounding is mixing of several components in a certain ratio to obtain a petroleum product of a given quality. The concept of sustainable development proclaimed by the international community is a conceptual base for the development of international and national policy in the field of environmental management and environmental protection considering close interrelation of the nature protection activity with economy and the social sphere. Concrete is an artificial stone material obtained from a rationally selected mixture of binder and aggregates. It is one of the main building materials. Condensate is a natural mixture of mainly light hydrocarbon compounds that are in a dissolved gas and are converted into a liquid phase, with a decrease in pressure, below the condensing pressure. Condensation is transition of a substance from the gaseous state into a liquid or solid phase. In case of a disperse system this term designates formation of a heterogeneous system from a homogeneous one as a result of association of molecules, atoms or ions in units. Contact devices are chemical reactors for conducting heterogeneous catalytic processes. Depending on the state of the catalyst and the mode of its movement in the apparatus, they are divided into: – contact apparatuses with a fixed catalyst bed; – contact apparatuses with a moving bed; – contact apparatuses with a fluidized bed. In addition, contact devices differ in: – the structure of the material flows of the components; – a method of supplying or removing heat; – and a number of other design features.
Contact node is the combination of a contact apparatus with devices for removing or supplying heat. Contaminant is a substance that causes deviation from the normal composition of the environment. Conventional fuel (CF) is the amount of energy in kW·h obtained from the complete combustion of 1 kg or 1 nm3 of fuel. This value is: for coal 8.0, natural gas 10.6, coke 7.2, fuel oil 15.4, reverse coke oven gas 4.8. For comparison, the same value for enriched uranium is 22.5·106. Conversion is the ratio of the amount of reagent converted into products to the total amount of reagent fed to the reactor inlet. At the same time the amount of reagent can be measured in various units (mole number, weight, etc.). The cost of production (S) is the sum of all the costs of the enterprise in monetary terms related to the manufacture and sale of a unit of mass (volume) of its products. The expenses of the enterprise which are directly connected with production represent factory prime cost and include costs of means of production, compensation and services of other enterprises, management and service of production. High costs of raw materials about 70-80% of the total costs are characteristic of chemical industry. Cracking is the process of breaking C-C bonds in a hydrocarbon molecule to form fragments with a lower molecular mass. This is one of the most important processes in oil refining, used to convert high-boiling oil fractions to components with a higher octane number. There is catalytic cracking and thermal cracking. Crude condensate is a liquid released from the gas directly in the field separators at the separation pressure and temperature. Crude oil is a naturally occurring mixture of hydrocarbons that usually includes small quantities of sulfur, nitrogen, and oxygen derivatives of hydrocarbons as well as trace metals. It exists in the liquid phase under normal surface temperature and pressure and its physical characteristics (density, viscosity, etc.) are highly variable. Crystallization is a process of formation of a crystal phase of solution, steam or other solid phase, usually by a decrease in temperature or evaporation of solvent. Cumene is a colorless liquid [C6H5CH(CH3)2] used as an aviation gasoline blending component and as an intermediate in the manufacture of chemicals. Curing (vulcanizing, vulcanization) is the process of rubber formation from rubber under the influence of vulcanizing agents, for example, sulfur. It consists in the cross-linking of polymer chains of rubber with each other into a single spatial grid. The current efficiency is the ratio of the practical mass of the electrolysis product to the theoretical calculated according to the laws of Faraday; it is indicated by the Greek letter η, expressed as a percentage. Cyclone is a device for extracting dust from industrial waste gases. It is in the form of an inverted cone into which the contaminated gas enters tangentially from the top; the gas is propelled down a helical pathway, and the dust particles are deposited by means of centrifugal force onto the wall of the scrubber.
D Deactivation of the catalyst is a partial reduction or complete loss of catalytic activity during operation of the catalyst. This term unites a fairly wide range of different processes and phenomena responsible for reducing catalytic activity. The most frequent reasons for the deactivation of catalysts are the change in the chemical composition of the catalyst under the conditions of the reaction medium, volatility of the active component, interaction of the active component with the carrier to form new phases, change in the dispersion of the active component, poisoning, crystallization, sintering, coking and catalyst contamination. Dealkylation is the removal of an alkyl group from aromatic compounds. Deasphaltened oil is the fraction of petroleum after the asphaltenes have been removed using liquid hydrocarbons such as n-pentane and n-heptane. Deasphaltening is a removal of a solid powdery asphaltene fraction from petroleum by the addition of the low-boiling liquid hydrocarbons such as n-pentane or n-heptane under ambient conditions. Deasphalting is a process of removing asphaltic materials from reduced crude using liquid propane to dissolve nonasphaltic compounds. Debutanization is distillation to separate butane and lighter components from higher boiling components. Debutanizer is a fractionating column used to remove butane and lighter components from liquid streams. De-ethanization is distillation to separate ethane and lighter components from propane and higher-boiling components; also called de-ethanation. De-ethanizer is a fractionating column designed to remove ethane and gases from heavier hydrocarbons. Degassing is the removal of dissolved gases from water by a chemical method in which gases are absorbed by chemicals, for example, in the case of carbon dioxide:
СО2 + Са(ОН)2 = СаСО3 + Н2О, or by physical methods of thermal deaeration in air or in vacuum. Degradation of the environment (from the French degradation – reduction, backward movement, deterioration, decline in quality): 1) general deterioration of the natural environment, joint deterioration of the natural and social environments (landscape degradation, soil degradation, etc.); 2) deterioration of the natural environment of human life as a result of natural phenomena (for example, volcanic eruptions, floods) or as a result of economic activities of man (destruction of natural ecosystems, pollution of natural waters, etc.). Degradation of the environment occurs due to the destruction or disturbance of the bonds that ensure the exchange of substances and energy within nature, between nature and man, which is caused by the activity of man, carried out without taking into account the laws of nature development. The degree of conversion or conversion (X) is the ratio of the mass of the raw material that entered into chemical conversion during the time τ to its initial mass. The product yield and the degree of conversion of raw materials are expressed in mass fractions or percent.
Dehydrogenation is the process of splitting off a hydrogen molecule from an organic compound. It is removal of hydrogen from a chemical compound; for example, removal of two hydrogen atoms from butane to make butene(s) as well as removal of additional hydrogen to produce butadiene. In industry it is used to convert ethane, propane, and butane into olefins (ethylene, propylene, and butenes). Dehydrocyclization is any process by which both dehydrogenation and cyclizetion reactions occur. Demethanization is the process of distillation in which methane is separated from the higher boiling components. The deposited catalyst is a heterogeneous catalyst in which the finely divided particles of the active component are located on the surface of the carrier. Example: in the Pt/Al2O3 hydrogenation catalyst, the dispersed particles of metallic platinum (the active component) are deposited on the surface of alumina (carrier). The deposition is a step of preparing the supported (put) catalysts, as a result of which the precursor of the active component passes from the solution or from the gas phase to the surface of the solid support. Different methods of application have their own names (for example, impregnation, deposition-precipitation, etc.). Desulfurization is a chemical treatment to remove sulfur or sulfur compounds from hydrocarbons. Detergent oil is a lubricating oil possessing special sludge-dispersing properties. Detoxication means: 1) destruction and neutralization of various toxic substances by chemical, physical or biological methods; 2) the process of neutralization within the biological system of harmful substances that have entered it. Detoxication of waste means their release from harmful (toxic) components on specialized installations. Dewaxing is the removal of wax from petroleum products (usually lubricating oils and distillate fuels) by solvent absorption, chilling, and filtering. Diesel engine (in common parlance – «diesel») is a reciprocating internal combustion engine that operates on the principle of spontaneous ignition of sputtered fuel from the action of air heated by compression. It is used mainly on ships, diesel locomotives, buses and trucks, tractors, diesel power stations, and by the end of the 20th century it became common on passenger cars. The diesel engine is named by its inventor. The first compression-ignition engine was created by Rudolf Diesel in 1897. The range of fuel for diesel engines is very wide, it includes all fractions of oil refining from kerosene to fuel oil and a number of products of natural origin – rapeseed oil, frying oil, palm oil and many others. The diesel engine can with some success work on crude oil. Diesel fuel is fuel used for internal combustion in diesel engines; usually that fraction which distills after kerosene. Differential selectivity is the ratio of the rate of formation of the target product to the total rate of consumption of the reagent due to all reactions. Unlike integral selectivity, differential selectivity depends only on the temperature and composition of the reaction mixture, and does not depend on the type of reactor.
Differential mode of the reactor is the mode of operation of the ideal displacement reactor, in which the conversion of the initial reactants at the outlet from the reactor remains low. Under such conditions, it can be assumed that the entire volume of the catalyst interacts with the reaction mixture in which the concentration of the reactants is the same. Diseases ecological is disruption of the normal life of the human body, caused by negative changes in environmental factors. Examples of such diseases are «itaita», «Minamata», «Yusho», etc. The disease «ita-ita» (literally translated – «oh-oh») is the result of poisoning by cadmium, known from 1955, from sewage waters of the Japanese concern «Mitsui» in the irrigation system of rice fields. Eating poisoned rice caused apathy, pain in different parts of the body, damage to kidneys and softening of bones. The disease «Minamata» is poisoning with methylmercury. The name of the disease is connected with Minamata Bay (Japan), where in the 1950s mercury-containing wastewater from the Chisso campaign was discharged. Mercury accumulated in fish, which was eaten by local people. The consequence was severe damage to the nervous system in the population, mental and physiological anomalies in every third newborn. The disease «Yusho» is poisoning with polychlorinated biphenyls (PCBs). In 1968, in Japan, in the process of cleaning rice oil, PCBs got into the oil, which resulted in poisoning of the population, accompanied by loss of weight, development of malignant tumors, liver, spleen, kidneys, skin darkening. The dispersed phase is a finely divided substance in the composition of a dispersed system. Dispersing is crushing or grinding of macroscopic particles of matter. Dispersion is a quantity that is equal to the ratio of the number of surface atoms to the total number of atoms in the particle. Dispersion is inversely proportional to the particle size. The higher the dispersion of the particles, the smaller their size and, hence, the higher the fraction of surface atoms. The dispersion medium is a part of the disperse system, in the volume of which the disperse phase is distributed. The dispersion system is a heterogeneous system containing a finely divided substance (dispersed phase), which is distributed in the volume of some other substance and does not mix with it (dispersion medium). Distillation is a process of physical separation of oil and gas into fractions (components), different from each other and from the initial mixture by temperature limits (or temperature) of boiling. By the process a simple and a complex distillation are distinguished. Doping is the formation of a solid solution when small amounts of foreign atoms are added to the crystal lattice of a nonmetallic catalyst. The term is generally applied to catalysts that are semiconductors. Doping changes the electronic properties of the catalyst, which can affect the rate of catalytic conversion. Dry gas is natural gas with such a little amount of natural gas liquids that it is nearly all methane with some ethane. Drying is the stage of preparation of catalysts, as a result of which the excess solvent is removed from the catalyst. Typically, drying takes place at elevated temperatures, but without any chemical transformation in the catalyst structure.
Drying in chemical technology is the process of removing moisture or other liquid from solid materials by evaporation and removal of the generated steam. The drying condition is to ensure the inequality Pm > Pc, where Pm is the vapor pressure in the wet material being dried, and Pc is the partial pressure of vapor in the environment. The drying process is carried out in dryers of various designs, at atmospheric pressure or in vacuum. Dry stripped gas (DSG) is a product of processing associated petroleum or natural gas. It is a methane with minor impurities of other hydrocarbons. It is used mainly as a fuel. E Eco-Industrial Park (EIP) is an association of producers of goods and services wishing to improve the economic and environmental situation through joint management of natural resources (energy, water and materials) and the environment. Working together, manufacturers hope to get a better collective effect than they would have individually. The goal of Eco-Industrial Park is to improve the economic status of participating producers and to reduce environmental pollution. Ecology is a synthetic science, which comprises three main directions: – general ecology or bioecology studies the relationship of living systems with the environment and with each other; – geoecology studies the dynamics of geospheres, including the biosphere, their interaction and geophysical conditions of life; – applied ecology studies aspects of engineering and social protection of human environment. The term «ecology» was proposed by E. Haeckel in 1886 and originally designnated one of the branches of biology, which studies the interrelationship of the species of living beings and their habitat. Ecology basic laws, which are directly related to the geoecology of subsoil use, include: – limitation of natural resources and a decline in natural and resource potential; – internal dynamic balance of ecological systems; – decrease in energy efficiency of subsoil use: optimality or rationality in geoecology. Ecology task as a science is to study human activity in the environment, as well as to study the processes of restoring the environment disturbed by man. Ecology is also a scientific basis for the rational use of natural resources, including minerals. Electrical Desalting Plants (EDP) are plants that are necessary to remove salt from crude oil in order to avoid corrosion of oil refining technology, increase its service life, reduce the cost of maintenance and repair of chemical reactors. EDP is the first installation through which the oil entering the plant must pass.
Effective density is the density of solid phase catalysts, determined on the basis of the volume of liquid that is displaced by the sample when it is placed in this liquid. The effective density values can differ significantly for different liquids due to the fact that a different degree of penetration of liquids into the pores of the catalyst is observed. The effective pore size is the diameter of the maximum circumference, which can be inscribed in a flat pore cross section. In this case, the plane section of the pore can have an arbitrary geometric shape. Efficiency of the catalyst is the number of molecules of the formed products referred to one molecule of the active centers of the catalyst. It is the cumulative characteristic of catalytic properties considering activity, selectivity and period of operation of the catalyst without loss of catalytic activity. Electrochemistry is a branch of physical chemistry that considers systems containing ions (solutions or melts of electrolytes) and processes occurring at the boundary of two phases with the participation of charged particles. It is divided into theoretical and applied. Thanks to the use of electrochemical methods, it is associated with other branches of physical chemistry, as well as analytical chemistry and other sciences. Electrode processes are processes associated with the transfer of charges across the boundary between the electrode and the solution. The cathodic processes are associated with the reduction of molecules or ions of the reacting substance, the anodic processes are associated with the oxidation of the reacting substance and with the dissolution of the electrode metal. Electrophilic catalysis is a catalytic reaction in which the catalyst is a Lewis acid. Example: Friedel-Crafts alkylation in the presence of aluminum chloride AlCl3. Emergency emission is unintentional release of pollutants into the environment (atmosphere, water, soil) as a result of an accident in technical systems. Emergency environment is an accident in which pollutants enter the environment in an amount that poses a threat to the environment, people and property. Emergency rescue works are actions to save people, material and cultural values, protect the natural environment in the emergency zone, localize emergencies and suppress or minimize the impact of specific hazards. They require special training, equipment and devices. Emissions are gas-dust substances to be discharged (released into the atmosphere) beyond production limits, including hazardous and / or valuable components that are trapped by the process gases and are disposed of in accordance with the requirements of national legislation and / or regulations. EMS-1 is a station, consisting of a KAMAZ automobile (a variant was developed on the basis of the Ural motor vehicle), in the back of which a multi-purpose universal modular laboratory is installed, equipped with instruments and equipment for sampling and analysis of water, soil air, meteorological parameters. The EMS-1 instrument complex consists of separate functional blocks, which can be combined into the following groups: – a set of instruments and equipment for sampling and analysis of air, water, soil samples;
– a meteorological station (measurement of temperature, air humidity, atmospheric pressure, wind speed and direction); – a radiation monitoring unit. The instrumentation of the station allows specialists to measure and monitor the following parameters: hydrogen sulfide, ammonia, nitrogen dioxide, carbon monoxide, sulfur dioxide in the air; hydrocarbon gas content in air samples; phenol in water samples; oil products in water and soil samples; phosphates, chlorides, sulfides in water samples; ionic composition and pH of water; heavy metals in water and soil samples; meteorological parameters; gamma radiation intensity. Energy intensity of production is the amount of energy spent on obtaining a unit of production. It is expressed in kW·h (kJ) or in tons of conventional fuel (CF) per ton of production. The energy intensity of individual industries varies very widely: from 20·103 kWh for aluminum to 60-100 kWh for sulfuric acid per ton of products. Enrichment is the process of separating the useful part of the raw material (useful component) from the waste rock (ballast) in order to increase the concentration of the useful component. As a result of enrichment, the raw material is divided into a concentrate of the useful component and tails with a predominance of waste rock in them. The degree of enrichment of raw materials is the ratio of the mass fraction of the useful component in the concentrate to its mass fraction in the enriched raw materials. The choice of enrichment method depends on the state of aggregation and differences in the properties of the components of the raw materials. Environmental disaster is an extraordinary event caused by a change in the state of land, atmosphere, hydrosphere and biosphere under the influence of anthropogenic factors, and consists in the manifestation of a sharp negative impact of these changes on human health, spiritual sphere, habitat, economy or gene pool. Environmental disease (ecogenic) is a disease that belongs to a group of diseases associated with unfavorable ecological conditions of the vital activity of the population – first of all, high content of heavy metals, chemical toxicants, increased radiation. Environmental expertise of chemical technologies is an estimate of the lowwaste production in comparison with the developed standards or the best available samples. At the same time, the degree of economic and ecological danger of the method of production and technological redistribution into the environment, etc., is determined. Environmental impact is any negative or positive change in the environment, wholly or partly resulting from the activities of the organization, its products or services. Environmental monitoring is a system for monitoring the environment from anthropogenic pollution associated with human activities. Since natural ecological systems closely interact with each other, this predetermines the complexity and necessity of taking into account various natural and chemical factors when controlling the quality of the environment. To assess the degree of negative impact of pollution, environmental monitoring is carried out as a system for observing and monitoring changes in the composition and functions of various ecological systems. Environmental monitoring can be carried out on a global, national, regional or local scale.
Environmental Monitoring Station (EMS) is a station (post) of environmental monitoring of air, an independent block design (block-box), designed to monitor atmospheric air, working area air and at the border of the sanitary protection zone. Environmental protection is a set of measures aimed at ensuring safety of human settlements, rational use of land and water, prevention of pollution of surface and groundwater, air basin, preservation of forest areas, nature reserves, protected zones, etc. EPA (The United States Environmental Protection Agency) is an agency of the US federal government established to protect the environment and human health, for which it develops and monitors compliance with the regulations based on laws, adopted by the Congress. The agency was proposed by Richard Nixon and began operating on December 2, 1970. The Agency is managed by an administrator appointted by the president and approved by the Congress. Since February 2017, this position has been occupied by Scott Pruitt. The administrator of the agency is a member of the US Cabinet. The EPA is headquartered in Washington, with regional offices in each of the 10 regions and 27 laboratories. The Agency conducts the environmental assessment, does research and engages in educational work. Its job is to monitor the implementation of the adopted standards and norms, some of these responsibilities are delegated to the states. The agency has about 15,000 full-time employees, and also works with many people on a contract basis. In March 2017, the Trump administration proposed to reduce by one-quarter the budget of the Environmental Protection Agency. By 2018, environmental spending will be reduced by 25% – to $ 6.1 billion. Each fifth employee will fall under reduction. At the same time, Trump guarantees that the project will not endanger the safety of air and water. The cost of the program in 2018 will be $ 29 million. Priority will be the sewage treatment programs, including industrial wastewater, and the modernization of the water supply system. Ethane is a naturally gaseous straight-chain hydrocarbon (C2H6) extracted from natural gas and refinery gas streams. Ethyl alcohol (ethanol or grain alcohol) is an inflammable organic compound (C2H5OH) formed during fermentation of sugars; used as an intoxicant and as a fuel. Evaporation is the process of concentration of solutions by evaporation of the solvent; most often this process is carried out at elevated temperatures, sometimes boiling, and / or under vacuum. Exhaust gases (off-gases) are the spent substances in the engine, products of oxidation and incomplete combustion of hydrocarbon fuel. Emissions of exhaust gases are the main reason for exceeding the permissible concentrations of toxic substances and carcinogens in the atmosphere of large cities, formation of smogs, which are a frequent cause of poisoning in confined spaces. Exhaust gas recirculation of the vehicle’s engine is restart-up of the fulfilled gases in the system of the car’s engine intake. Expanding clays are clays that expand or swell in contact with water, e.g., montmorillonite. Expense ratio (β) is the amount of raw materials, water or energy (Q) spent on the production of a unit of mass or volume of the target product (m). For raw materials, β is expressed in t/t, nm3/t, nm3/nm3; for energy, respectively, in kW·h/t, kW·h/nm3.
Explosive limits are the limits of percentage composition of mixtures of gases and air within which an explosion takes place when the mixture is ignited. External surface is an external surface of particles of catalysts and adsorbents without their internal porous structure (an internal surface). Usually, superficial pores and cavities are also referred to the external surface if their width exceeds the depth. Extinction is disappearance of any systematic category of living species (from subspecies and higher) as a result of natural processes or human impact. In the epoch of extinction of dinosaurs, one species disappeared in 1000 years, from 1600 to 1950 – one species disappeared in 10 years, and now – 1 species per year. Extrudate is a product obtained by extrusion. Extrusion is a formation method in which a paste is extruded through a spinneret. The size of the holes in the spinneret determines the size and shape of the resulting particles. The quality of the product (extrudate) depends to a large degree on the water content and rheological properties in the initial paste, which are regulated by special additives. F Faujasite is a naturally occurring silica-alumina (SiO2-A12O3) mineral. Feedstock is petroleum as it is fed to the refinery; a refinery product that is used as the raw material for another process; the term is also generally applied to raw materials used in other industrial processes. So, it is a stock from which material is taken to be fed (charged) into a processing unit. Fertilizers are substances that contain elements necessary for plant nutrition or regulation of soil properties. Classification of fertilizers: mineral fertilizers are inorganic compounds that contain essential elements for plants; organomineral fertilizers are humic fertilizers, fertilizers consisting of organic matter and related chemical or adsorption-mineral compounds. Classification of fertilizers by agrochemical purpose: – direct – source of nutrients for plants; – indirect – serve to mobilize soil nutrients by improving its physical, chemical and biological properties. Classification of fertilizers by the number of nutrients: – simple (one-sided) fertilizers – contain one main nutrient: nitrogen, phosphorus or potassium. These are nitrogen, phosphorus and potash fertilizers; – complex fertilizers (CF) – contain two or three main nutrient elements. They are divided into double (such as, for example, nitrogen-phosphorus (NPh), nitrogen-potassium (NP) or phosphorus-potassium (Ph-P)) and triple (nitrogenphosphorus-potassium (NPhP)). Complex fertilizers (CF) are divided into: – mixed CF, i.e. mechanical fertilizer mixtures consisting of dissimilar particles; – complex CF, i.e. complex compounds resulting from chemical interaction.
According to the state of aggregation, fertilizers are divided into solid and liquid (for example, ammonia water, aqueous solutions and suspensions). The Fischer-Tropsch process is a catalytic process for production of liquid hydrocarbons from synthesis gas. Metal catalysts containing iron and cobalt are generally used. Due to exhaustion of world reserves of hydrocarbonic raw materials this process was of particular importance for production of synthetic fuels and lubricant coal oils. The fixed catalyst is an immobilized catalyst in which the active site is attached to the carrier by a covalent chemical bond. Typically, this term refers to systems in which the surface functional group of a carrier is covalently bound to one of the ligands in the organometallic complex. Such a system retains the properties inherent to free metal complexes in solution, including, for example, the mechanism of catalytic conversion. The advantage of fixed catalysts compared with metal complexes in solution is the possibility to separate the catalyst from the reaction mixture by filtration. Flame neutralizer of exhaust gases of the car engine is the device for neutralization of the exhaust gases of the engine by a method of afterburning in an open flame. The flammability group – the term is used in determining the category of production in case of fire and depending on the flash point. Flammable liquids (FL) are combustible liquids with a flash point in a closed crucible not above 61 °C. FL are subdivided into especially dangerous – having a flash point below -18 °C, constantly dangerous – with a flash point from-18 to 23 °C and dangerous at elevated temperature – with a flash point from 23 to 61 °C. The flash point is the lowest temperature of a combustible substance, at which vapor or gases are generated above its surface that can flare in the air from the ignition source, but the rate of their formation is still insufficient for sustainable combustion. The flowing and circulating reactor is the reactor used in laboratory research in which the catalyst is in a circulating contour with rapid circulation of reactionary mixture through the catalyst. Reagents with a constant speed are entered into a contour, and products with a constant speed are taken away from a contour. Due to rapid circulation of a mixture in the contour a number of advantages is reached (constant temperature is established, influence of external diffusion, etc., is eliminated). Flotation is a method of enrichment of solid raw materials, based on the difference in the wettability of its components, for example, in the preparation of iron from iron pyrites. To speed up the flotation process, the system is foamed by intensive mixing (mechanical flotation machines) or air bubbling through the system (pneumatic flotation machines). The result of flotation depends on the difference in the hydrophobicity (hydrophilicity) of the components of the enriched raw material. The flowing reactor is the reactor of continuous action having a constant stream of reagents at the entrance to the reactor and a constant stream of products at the exit from the reactor. The fluidized bed reactor is a reactor in which solid catalyst particles (0.01-0.1 mm in size) are suspended in an upward flow of gaseous reactants. The advantages of this type of reactor are the intensive heat exchange between the catalyst particles, the absence of external diffusion inhibition, and the ease of catalyst loading. The lack of
a fluidized bed is an increased abrasion of the catalyst particles. Reactors of this type are suitable for reactions with very high heat release, or in cases where the catalyst needs frequent replacement. The fluidized bed reactor is a fluidized bed reactor containing a gas, liquid, and a solid phase. Forming is a stage of preparation of catalysts which is responsible for the external sizes and a form of particles of the ready catalyst. Forming can be carried out by various methods (spray drying, extrusion, tabletting, granulation, etc.). Fraction is one of the portions of fractional distillation having a restricted boiling range. It is the share of petroleum which is boiling away in a particular interval of temperatures. Fraction С2+ is a mixture of hydrocarbons with the number of carbon atoms from 2 and above. Most often, this term means light hydrocarbons with a carbon number of up to 5. Fractional composition is an important indicator of quality of petroleum. It is defined at laboratory distillation in the course of which at gradually increasing temperature the parts – the fractions differing from each other in the range of boiling are distillated from petroleum. Fractional composition of petroleum shows the content of various fractions in it which are boiling away in particular temperature intervals and shows the content of substanses in them. Fractionating column is a process unit that separates various fractions of petroleum by simple distillation, with the column tapped at various levels to separate and remove fractions according to their boiling ranges. Free sulfur is sulfur that exists in the elemental state associated with petroleum; sulfur that is not bound organically within the petroleum constituents. A free-dispersing system is a dispersed system in which the particles of a dispersed phase freely participate in Brownian motion, for example, sol. Fuel Gas is a refinery gas used for heating. Fuel oil is also called heating oil, it is a distillate product that covers a wide range of properties. Functional group is the portion of a molecule that is characteristic of a family of compounds and determines the properties of these compounds. G Gallon is a unit of measurement of volume, equal to ≈ 3,785 l. Gas is a natural mixture of hydrocarbon, non-hydrocarbon compounds and elements that are in formation conditions in the gaseous phase, or dissolved in oil or water conditions, and under standard conditions – only in the gaseous phase. Gas analyzers are devices for determining the qualitative and quantitative composition of gas mixtures contained in the atmosphere. Gas analyzers make it possible to obtain continuous air pollution characteristics and to identify maximum concentrations of impurities that may not be recorded during periodic sampling of air several times a day. The gas cap is the accumulation of free oil gas in the most elevated part of the oil reservoir above the oil deposit.
Gas cleaning is a set of measures and (or) technologies aimed at capturing solid, liquid or gaseous substances contained in the gas emissions of industrial enterprises in the atmosphere. The gas field – the term means one or several gas deposits, confined territorially to one area, or associated with a favorable tectonic structure (anticlinal fold, dome, etc.) or other type of trap. Gas factor is the amount of natural gas (in cubic meters) per 1t or 1m3 of oil. Gas flow is the amount of gas in volume or weight terms, released from a well or from any source per unit of time (per hour, per day, etc.). Gas-condensate deposit is a deposit in which hydrocarbons in the conditions of the existing reservoir pressure and temperature are in gaseous state. At decrease of pressure and temperatures the phenomenon of the so-called «return condensation» at which hydrocarbons partially pass into a liquid phase takes place and remain in pore channels of layer from which it is difficult to extract. The operation of the gas condensate deposit in order to avoid these losses must be done with maintaining the pressure above the reverse condensation point, for which the injection of extracted gas back into the formation after its topping is organized. Gas condensate factor is the amount of gas (m3) from which 1 m3 of condensate is extracted. The value of gas condensate factor can be for the various fields from 1, 500 to 25, 000 m3/m3. Gas hydrates are solid compounds (clathrates) in which the gas molecules under certain temperature and pressure fill the structure cavities of the crystal lattice formed by water molecules by means of hydrogen bonding. The water molecules are moved apart by gas molecules – density of water in hydrated state is increased to 1.26-1.32 cm3/g (ice density – 1.09 cm3/g). Externally, the hydrates look like snow. They are typically formed at temperatures below 30°C, at pressures greater than 0.5 MPa. Disintegration of gas hydrates is possible when the temperature rises with decreasing pressure, and by entering into the reservoir of substances which decompose hydrate, such as calcium bromide. Gas mode (dissolved gas mode) is the mode of operation of the oil deposit in which oil is entrained to the bottom of the wells by the more mobile masses of the expanding gas that have passed when the pressure in the reservoir decreases below the saturation pressure from the dissolved state to the free state. Gas oil is a middle-distillate petroleum fraction with a boiling range of about 175 – 400 ºC, usually includes diesel fuel, kerosene, heating oil, and light fuel oil. It is a petroleum distillate with a viscosity and boiling range between those of kerosine and lubricating oil. Gas-oil ratio is a ratio of the number of cubic feet of gas measured at atmospheric (standard) conditions to barrels of produced oil measured at stocktank conditions. Gaseous pollutants are gases released into the atmosphere that act as primary or secondary pollutants. Gasoline is a blend of naphthas and other refinery products with sufficiently high octane and other desirable characteristics to be suitable for use as fuel in internal combustion engines. It is fuel for the internal combustion engine that is commonly, but improperly, referred to simply as gas.
The gas-oil reservoir is a reservoir in which free gas occupies the entire higher part of the structure and is directly in contact with oil occupying a reduced part of the structure in the form of a rim, and the volume of the oil part of the deposit is much smaller than the volume of the gas cap. At a large depth of bedding, the gas cap, regardless of its size, may contain petroleum hydrocarbons in the gascondensate state. Gasoline type jet fuel (naphtha type jet fuel) includes all light hydrocarbon oils for use in aviation turbine power units, distilling between 100°C and 250°C. It is obtained by blending kerosenes and gasoline or naphthas by the method at which the aromatic content does not exceed 25% in volume, and the vapour pressure is between 13.7kPa and 20.6kPa. Gas processing plant (GPP) is an enterprise where drying, desulfurization (removal of sulfur compounds) and separation of associated oil or natural gas into components – methane and other hydrocarbons takes place. The gas saturation pressure is a pressure at which a certain volume of gas is in a dissolved state in the oil. The general chemical technology is a science about the most economic chemical ways of processing of raw materials into target products and means of production. General chemical technology is divided into mechanical technology, which studies the processes associated with changes in size, shape, state of aggregation, the crystalline structure of substances, and chemical technology. Geoecology is a scientific direction that studies the Earth as a system of geospheres in the process of their interaction with the whole aggregate of living matter. Global ecology is a complex scientific discipline that studies the biosphere as a whole. The fundamentals of global ecology were formulated by M.I. Budyko, who considered it as a central problem of the cycle of substances in the biosphere. Global warming is an increase in the average temperature of the atmosphere in the scale of the planet, caused by a combination of natural and / or technogenic factors. Granules are the substances in the form of unbound particles with a size of more than 1 mm. Granulation is a method for forming granules from powders. Usually, this procedure is performed when the powder is moistened in a rotating drum. Grinding is a mechanical process of dividing a solid body into parts due to the application of external forces. Grinding can be carried out by impact, crushing and abrasion. Grinding of particles up to 10-3 m is called crushing and is carried out in crushers, grinding from 10-3 to 10-6 m is called grinding (splitting) and is carried out in mills. H Hardness of water is the most important characteristic of water, which largely determines the possibility of its use. Hardness is determined by the content of calcium and magnesium ions in the water. It is measured in mol-eq / m3 (mol / m3) or mmol-eq / l (mmol / l).
According to the value of the total hardness, natural waters, as a rule, are divided into a number of groups: – very soft water (10.7 mol/m3). Among natural waters, the softest water is rainwater, the hardness of which is approximately 0.070-0.1 mol/m3. The hardness of groundwater varies widely from 0.7 mol/m3 to 18-20 mol/m3 and depends on the composition of the rocks in contact with them. Harmful substances are called substances which at contact with a human body, in case of violation of safety requirements, can cause the production injuries, professsional diseases or deviations in the state of health found by the modern methods both in the course of work, and in the remote terms of life of this and subsequent generations. They are chemical or biological substances or a mixture of such substances that are contained in the ambient air and which in certain concentrations have harmful effects on human health and the environment. Heterogeneous catalysis is a phenomenon of the change in the rates of chemical reactions under the influence of catalysts, which form a separate phase, while the reagents are in a different phase. The reactants contact with the catalyst at the interface. The most widespread systems are those in which reactants from a liquid or gaseous phase interact with a solid catalyst. The heterogeneous catalyst is a catalyst existing in the reaction mixture as a separate phase. A catalytic reaction involving a heterogeneous catalyst necessarily takes place at the phase boundary. Unlike a homogeneous catalyst, the advantage of a heterogeneous catalyst is the ease of separating the reaction products from the catalyst. High-boiling distillates are fractions of petroleum that cannot be distilled at atmospheric pressure without decomposition, e.g., gas oils. High-sulfur petroleum is a general expression for petroleum having more than 1 wt % sulfur; this is a very approximate definition and should not be construed as having a high degree of accuracy because it does not take into consideration the molecular locale of the sulfur. All else being equal, there is little difference between petroleum having 0.99 wt% sulfur and petroleum having 1.01 wt% sulfur. Hydrocarbon compounds are chemical compounds containing only carbon and hydrogen. Hydrocarbon gasification process is a continuous, noncatalytic process in which hydrocarbons are gasified to produce hydrogen by air or oxygen. Hydrocarbon resources are resources such as petroleum and natural gas that can produce naturally occurring hydrocarbons without the application of conversion processes. Hydrocarbon-producing resource is a resource such as coal and oil shale (kerogen) which produces derived hydrocarbons by the application of conversion processes; the hydrocarbons so-produced are not naturally-occurring materials.
Hydrocracking is a catalytic process, the cracking of heavy hydrocarbons in the presence of hydrogen H2. In addition to cracking reactions, hydrogenolysis, hydrogenation of aromatic hydrocarbons, the opening of cycles in naphthenes, hydrodealkylation of alkylaromatic compounds and naphthenes occur. Hydrocracking catalysts can be oxides and sulphides of Ni, Co and Mo. Hydrodenitrogenation is the removal of nitrogen by hydrotreating. Hydrodemetallization is the removal of metallic constituents by hydrotreating. Hydrogeneration is the chemical addition of hydrogen to a material in the presence of a catalyst. Hydrodesulfurization is a catalytic process of removal of sulfur from oil or its fractions by hydrogenation of sulfur-containing compounds to form hydrogen sulfide and convert to hydrocarbons and H2S. The process is carried out in the presence of hydrogen H2. The catalysts are supported oxides of Co and Mo, which under the process conditions become sulfides. Hydrogenolysis is a catalytic process of rupture of C-C or C-X bonds (X = N, S, O, etc.) in hydrocarbons under the action of hydrogen H2. It is carried out on catalysts of hydrogenation and dehydrogenation (for example, metal catalysts). Often, the hydrogenolysis reaction requires high temperatures and a strong binding of the reactants to the catalyst and is therefore difficult to implement. A hydrometer is a device for measuring the density of liquids and solutions, made in the form of a float (a tube with divisions and a load below). By the depth of immersion of the hydrometer in a liquid or solution, their relative density is found. Hydrothermal synthesis is a method of obtaining carriers and catalysts in aqueous solutions at temperatures above 100°C and pressures above 1 atm. Under such conditions, water can dissolve many substances (oxides, silicates, sulfides), which under normal conditions are practically insoluble. Advantages of the method are the ability to synthesize large crystals of high quality, as well as the possibility of obtaining crystals of substances that are unstable near the melting point. The main parameters of hydrothermal synthesis are the initial pH of the medium, the duration and temperature of the synthesis, the amount of pressure in the system. Hydrotreating is the removal of heteroatomic (nitrogen, oxygen, and sulfur) species by treatment of a feedstock or product at relatively low temperatures in the presence of hydrogen. I The ignition temperature is a temperature of combustible substance at which it emits combustible vapors and gases with such a speed that after their inflaming from a source of ignition there is a steady combustion. The Ili-Ridil mechanism is a mechanism of a heterogeneous catalytic reaction, in which the compound adsorbed on the surface of a solid catalyst reacts with a molecule from the gas or liquid phase. The impact of anthropogenic is the sum of direct and indirect effects of human activities on the environment, including human health and safety, flora, fauna, soil, air, water, climate, landscape and historical monuments or other physical structures or the interaction among these factors.
Impact on climate are changes in the global energy of the Earth as a result of the accumulation of carbon dioxide and other «greenhouse gases», changes in the density of the ozone screen, direct release of energy, etc. It is assumed that, while maintaining current trends in the climate, the average world air temperature by the middle of the 21st century can rise by 2-4.5 °C. Impurities are substances that are present in small (trace) amounts in the feed, or in the catalyst. Usually this term implies that within the developed chemical technology it is difficult to control the composition of these substances and their quantity. The inhibitor is a substance that slows down the chemical reaction. This term is applied to any reactions (catalytic, non-catalytic, chain). Sometimes for such substances the term negative catalyst is used, which is not recommended by IUPAC rules. The effect of inhibitors can be due to a variety of mechanisms. For example, some inhibitors are irreversibly consumed during the reaction. In case of enzymatic reactions chemical linkng of inhibitor with enzyme is the frequent reason of delay of reaction. Industrial cleaning (or purification) is the purification of gases for the purpose of subsequent utilization or return to production of separated gas or a product transformed into a harmless state. This type of purification is a necessary stage of the technological process with this technological equipment connected to each other by material flows in accordance with the strapping of the apparatus. Industrial ecology is the scientific basis of rational nature management. It is the independent scientific studying of the influence of industrial activity on the biosphere and its evolution in a technosphere and also defining ways of transition of a technosphere, rather painless for a human civilization, to a noosphere. The methodical basis of a course of industrial ecology is scientific analysis of the ecological characteristic of production (technological process, hardware, raw and auxiliary materials, their possible impact on the environment). On the basis of a detailed analysis, the real impact of production (production complexes) on the biosphere is evaluated, a forecast of the state of the environment is given, and measures to minimize the impact of economic entities on nature are planned. The main areas of industrial ecology are: – greening of technologies; – creation of low-waste processes; – cleaning the atmosphere and water resources from harmful impurities; – processing of solid waste (or its burial); – use of economic and legal levers for environmental protection. Industrial ecology purposes are solution of problems of rational use of natural resources, prevention (at the first stage – restriction) of environmental pollution, combination of technogenic and biogeochemical circulations of substances. In other words, industrial ecology is a means for sustainable functioning of ecological and economic systems. Index group is a part of atoms of the reacting molecule which directly interacts with the surface of the catalyst at adsorption. The induction period is the initial stage of the chemical transformation, during which an increase in the reaction rate is observed (self-acceleration of the reac-
tion). The induction period can be observed in catalytic processes due to various factors (for example, autocatalysis, heating of the system in the case of highly exothermic reactions, adsorption of interfering impurities from the reaction mixture onto the catalyst, etc.). The integrated mode of the reactor is an operating mode of the reactor of ideal replacement at which considerable conversion of initial reagents at the outlet from the reactor is reached. The intensity (I) is a criterion of overall performance of the device. It allows us to compare devices of various powers by efficiency and is expressed in kg/m3 or kg/m2. The intensity (the device, the car, the reactor) is the ratio of its productivity to the unit of the size characterizing the sizes of the working part of the device – the volume of the reactor V or the area of its section S: I = P/V or P/S, where P is productivity. The interface of the phases is the boundary separating the two neighboring phases. Sometimes this term refers to a surface layer thickness of a few atoms, which are different in energy from atoms in the bulk of each phase. For solid particles, this is an external monolayer consisting of a regular matrix of surface atoms (or ions), as well as internal and external surface defects of various types. Internal surface is a part of an interface of phases which belongs to pores in particles of the catalyst or adsorbent. The other part of the surface belongs to the external (geometrical) surface of particles. At high porosity the internal surface can considerably (to 106 times) surpass the external surface in the area. Isomerization is a catalytic process for obtaining high-octane components of commercial gasoline from low-octane oil fractions. As a result of the process, linear hydrocarbons are isomerized into branched hydrocarbons. Heterogeneous acid catalysts of various types are used: aluminoplatinum fluorinated catalysts (high-temperature isomerization, 360-440 °C), zeolite catalysts (medium-temperature isomerization, 250-300 °C); alumina promoted by chlorine, or sulfated zirconium oxide (lowtemperature isomerization, 120-180 °C). Isomerism is the phenomenon of existence of compounds that have the same composition (the same molecular formula), but a different structure. K Kerosene (kerosine) is a fraction of petroleum that was initially used as an illuminant in lamps; a precursor to diesel fuel. Kerosene type jet fuel is a distillate used for aviation turbine power units. It has the same distillation characteristics between 150 °C and 300 °C (generally not above 250 °C) and flash point as kerosene. The kinetic mode is implementation of catalytic reaction in conditions when the kinetics of the process isn't complicated by diffusion processes (for example, the intra kinetic mode for the heterogeneous catalyst).
The Kipp apparatus is a device for producing gases in laboratory conditions, based on the interaction of an acid with an appropriate reagent (with a metal to produce hydrogen, with calcium carbonate to produce carbon dioxide, with iron (II) sulfide to produce hydrogen sulfide, etc.) L Labor productivity is the amount of the target product produced by the worker per unit of time. It depends on the achievements of scientific and technological progress, improvement of the organization of production, professional level of staff. Laminar flow is the flow of a liquid or gas, in which particles of matter move in the direction of flow in an orderly and constant linear velocity. An increase in the flow rate or a decrease in the viscosity of the medium can lead to the transition of a laminar flow into a turbulent flow. The Langmuir-Hinshelwood mechanism is the mechanism of a heterogeneous catalytic reaction, in which the slowest stage is the reaction between chemisorbed particles. In this case, the adsorption (chemisorption) of the reagents and the desorption of the products are considered as fast equilibrium processes. Leaching is the transition into a solution of one or more components of a solid substance when it interacts with a solvent. The selectivity of the leaching of a particular component is determined by the solubility of the compounds, the chemical properties of the solvent, and the structure of the solid. Examples of leaching: alkaline extraction of lignin from wood, dissolution of sugar from beet and sugar cane in hot water, extraction of metals from ores and concentrates. Leaded gasoline is gasoline containing tetraethyl lead or other organometallic lead antiknock compounds. Lean gas is the residual gas from the absorber after the condensable gasoline has been removed from the wet gas. Lean oil is the absorption oil fed to absorption towers in which gas is to be stripped. After absorbing the heavy ends from the gas, it becomes fat oil. When the heavy ends are subsequently stripped, the solvent again becomes lean oil. The level of pollution of the environment by the waste production is estimated by the multiplicity of excess of maximum permissible (allowable) concentration (MPC or MAC) of entering substances in natural objects. The biggest part of hydrocarbon pollution goes to the atmosphere, about 75%, 20% goes to the surface and ground waters, and 5% – in the soil. The lifetime, τ, is the lifetime of the molecule, which is destroyed by the firstorder kinetics, the time of the molecule concentration decrease by 1/e from its initial value. The lifetime is equal to the reciprocal of the rate constants of the first-order reactions leading to the death of the molecule. The lifetime of particles in reactions not of the first order depends on the initial concentration of the substance. In this case it is called the «observed time of life» or the «death time». In some cases one must use the half-decay time that is the time of reduction in the concentration of the substance by half from the initial. Light hydrocarbons are hydrocarbons with molecular weights less than that of heptane (C7H16).
Light oil is the products distilled or processed from crude oil up to, but not including, the first lubricating-oil distillate. Light petroleum is petroleum having an API gravity greater than 20º. Ligroine (Ligroin) is a saturated petroleum naphtha boiling in the range of 20 to 135 °C (68 to 275 °F) and suitable for general use as a solvent; also called benzine or petroleum ether. Lime is an astringent material obtained by firing and subsequent processing of limestone, chalk and other calcareous-magnesian rocks. Pure lime is a colorless product, poorly soluble in water (about 0.1% at 20 °C), with a density of 3.4 g/cm3. Lime was used mainly for the preparation of binding solutions in the construction of buildings. Over time, its application has expanded, and now it and substances based on it are used in many industries, agriculture, and even in environmental protection. In the metallurgical industry, lime allows the metal to be purified from phosphorus, sulfur, or silicon impurities that are formed when oxygen is introduced into molten iron or steel. The limiting stage is the elementary stage in the complex process (consisting of several consecutive stages) which is characterized by the difference of chemical potentials, maximum for the process, between the interacting reactionary groups. For simple and quite often for complex chemical processes the limiting stage can coincide with the speed – defining (speed – controlling) stage. The Liquefied Hydrocarbon Gases (LHG) are the hydrocarbonic gases or their mixtures with temperatures of boiling from –50 to 0 °C compressed under pressure. The major LHG are propane, butane, isobutane, butylene of various structure and their mixtures of different structure. They are made generally from associated petroleum gas, and also at oil refineries. Liquefied natural gas (LNG) is natural gas cooled to approximately –160 °C under atmospheric pressure, when it condenses to its liquid form called LNG. LNG is odourless, colourless, non-corrosive and non-toxic. Liquefied petroleum gases (LPG) are light paraffinic hydrocarbons derived from the refinery processes, crude oil stabilisation and natural gas processing units. They consist mainly of propane (C3H8) and butane (C4Hl0) or a combination of the two. They could also include propylene, butylene, isobutene and isobutylene. LPG are normally liquefied under pressure for transportation and storage. The liquid neutralizer of exhaust gases of the car engine is the device for neutralization of the exhaust gases of the engine of the car by a method of chemical binding by liquid reagents. Liquid Off Take System (LOT system) is an advanced concept in multi-cylinder installations. This system is widely used in commercial and industrial applications only where high pressure is required, and not for domestic purposes. The LOT system picks up the liquid LPG using the LOT valves and turns into steam using an evaporator. LOT systems are compact, safe and economical, since the liquid is completely drawn out of the cylinder and has no residual losses. About a half of losses of oil when transporting is the share of loading of ballast and cleaning of tankers. Though 80% of the world tanker fleet use the system of control actions of Liquid off Take System (LOT) for reduction of amount of the oil products getting to the sea in the course of release from ballast more than 70% of pollution of the sea are the share of 20% of the tankers which do not apply the LOT system. The LOT
system differs in the fact that as ballast in it water and oil products at the same time are used. Less dense oil products settle down in the top part of tanks, and rather clear sea water merges from the lower part in the sea. The oil products mixed with a small amount of sea water remain in tanks and then are overloaded on the next tanker at its filling except for some special cases when oil doesn’t contain impurity of sea water. Advantages of LOT systems: – less space is required than volumetric installations, – there are no residual losses – constant pressure. Lubricants are hydrocarbons produced from distillate by-products; they are mainly used to reduce friction between bearing surfaces. They include all finished grades of lubricating oil, from spindle oil to cylinder oil, and those used in greases, including motor oils and all grades of lubricating oil base stocks. M Macrokinetics is the study of kinetic regularities of chemical reactions, under conditions when they are accompanied by heat transfer and mass transfer phenolmena. Macropores are the pores with an effective size of more than 50 nm. A massive catalyst is a heterogeneous catalyst, consisting entirely of an active component, for example, Raney nickel. Mass transfer is the diffusion of substance or convection resulting from the difference in concentrations or electric potentials in the considered initial and final states. Material balance is an expression of the law of conservation of mass: the mass of substances (m) received for a technological operation (input) is equal to the mass of substances obtained in this operation (consumption), and is written in the form of a balance equation:
Σminput = Σmconsumption The material balance is compiled per unit mass of the target product or per unit (reactor) and is expressed in mass units (kg, t) or mass fractions (μ). For periodic processes, the material balance is compiled for one operation, for continuous processes – per unit of time. On the basis of the material balance, expenditure coefficients are calculated, the size of the apparatus is determined and the optimal values of the parameters of the technological mode of the process are established. A material flow is a graphic display of the movement and change of substances involved in the chemical process. The material flow is expressed in the form of a material-flow graph (MFG) of the process, that is, a graphic scheme that reflects the nature of the substance, the direction of its movement, the change in the state of aggregation and chemical composition. In MFG, there are «knots», that is, devices and machines, and «edges» – substances moving in the process.
Material flows can be of three types: – divergent, in which the number of products increases as a result of the process (for example, electrolysis of an aqueous solution of sodium chloride), – converging, in which the number of products as a result of the process is reduced (for example, ammonia synthesis), – intersecting, in which the number of products as a result of the process does not change explicitly (for example, roasting of pyrites). The maximum allowable (permissible) concentrations (MAC or MPC) are concentrations of substances that, with daily (except weekend) work for 8 hours or with a different working day, but not more than 41 hours a week, cannot cause diseases or abnormalities in the state of health during the whole working period. The harmfulness of the substance can be judged by MAC of them in the air of the working area. The mechanism of the chemical process is the set of all intermediates and transition states of the chemical process, which explains the transformation of the initial reagents into final products. Mercaptans are organic compounds having the general formula R-SH. Mercury porometry is a method of porosimetry based on the property of liquid mercury not moisten (wet) the majority of solid bodies. The volume of mercury entering the pores is measured, depending on the applied pressure. The method can be used to determine the pore size in a wide range (from 3 nm to 400 μm). Mesopores are pores with an effective size of 2 nm to 50 nm. Methanation is a catalytic process of removing small amounts of carbon monoxide from a gas stream. It leads to the production of methane by the reaction CO + 3H2 → CH4 + H2O. Nickel supported on alumina is used as the catalyst. The process can be carried out at any pressure, typical process temperatures are 200370°C. Methyl alcohol (methanol; wood alcohol) is a colorless, volatile, inflammable, and poisonous alcohol (CH3OH) traditionally formed by destructive distillation of wood or, more recently, as a result of synthetic distillation in chemical plants. Micropores are pores with effective size less than 2 nm. The microspherical catalyst is the catalyst in the form of microspheres with a diameter from 20 to 200 microns used in a fluidized bed reactor. The moisture capacity of the carrier is the amount of solvent that is absorbed when the porous system is filled in a pre-dried carrier. Mineral oil is the older term for petroleum; the term was introduced in the nineteenth century as a means of differentiating petroleum (rock oil) from whale oil which, at the time, was the predominant illuminant for oil. Mineral seal oil is a distillate fraction boiling between kerosine and gas oil. Mineral wax – from yellow to dark brown, solid substances that occur naturally and are composed largely of paraffins; usually found associated with considerable amount of mineral matter, as a filling in veins and fissures or as an interstitial material in porous rocks. Mineralization is the process of complete conversion of organic matter to carbon dioxide, water and other simple inorganic substances, depending on the heteroatom in the starting material.
A mixed catalyst is a catalyst consisting of two or more components, each of which is catalytically active with respect to the reaction. Usually, in mixed catalysts, the components are in commensurate amounts. An increase in the activity of such catalysts can be achieved through the interaction of the components with the formation of a new more active phase. Example: iron-molybdenum catalyst for the oxidation of methanol to formaldehyde has the highest activity at a ratio of iron and molybdenum oxides of 1.5 : 1 (the phase of iron molybdate is formed). Modifier – this term is used in asymmetric catalysis and means a chiral substance, without which the catalyst cannot produce an optically active product. For example, the Raney nickel catalyst is capable of performing asymmetric hydrogenation reactions if an optically active isomer of tartaric acid is present on its surface. Monitoring is a system of long-term observation, assessment, monitoring and forecasting of the state and change of the objects. A monomer is a component of a polymer, its structural unit, a molecule capable of polymerization or polycondensation. It usually contains one (olefins) or two (dienes) double bonds involved in the polymerization. The morphology is geometrical features of the structure of solid substances, including a geometrical form and degree of crystallinity of particles of the substance, and also a geometrical form of the agglomerates formed of primary particles and the presence in them of porous structure. Motor gasoline consists of a mixture of light hydrocarbons distilling between 35°C and 215°C. It is used as a fuel for land-based spark ignition engines. Motor gasoline may include additives, oxygenates and octane enhancers. Motor gasoline can be divided into two groups: – unleaded motor gasoline: motor gasoline where lead compounds have not been added to enhance octane rating. It may contain traces of organic lead. – motor gasoline with Pb added to enhance octane rating. They include motor gasoline blending components (excluding additives/oxygenates), e.g. alkylates, isomerate, reformate, cracked gasoline destined for use as finished motor gasoline. Motor octane method is a test for determining the knock rating of fuels for use in spark-ignition engines. Multifunctional (polyfunctional) catalysis is a complex difficult multistage catalytic reaction with participation of the multifunctional (polyfunctional) catalyst. Multifunctional (polyfunctional) catalyst is a catalyst containing active centers with different functions. Such catalysts are effective in reactions with several intermediate stages, each of which requires catalytic centers of its own type. N Naphtha is a generic term used for low boiling hydrocarbon fractions that are a major component of gasoline. Aliphatic naphtha refers to those naphthas containing less than 0.1% benzene and with carbon numbers from C3 through C16. Aromatic naphthas have carbon numbers from C6 through C16 and contain significant quantities of aromatic hydrocarbons such as benzene (>0.1%), toluene, and xylene. Naphtha is a feedstock destined for petroche-
mical industry (e.g. ethylene manufacture or aromatics production). Naphtha comprises material in the 30°C and 210°C distillation range or part of this range. This term is also applied to refined, partly refined, or unrefined petroleum products and liquid products of natural gas, the majority of which distills below 240°C (464°F). Naphthenes are hydrocarbons (cycloalkanes, cycloparaffins) with the general formula CnH2n, in which the carbon atoms are arranged to form a ring. Natural gas comprises gases, occurring in underground deposits, whether liquefied or gaseous, consisting mainly of methane. It includes both «nonassociated» gas originating from fields producing hydrocarbons only in gaseous form, and «associated» gas produced in association with crude oil as well as methane recovered from coal mines (colliery gas). Natural gas liquids (NGL) are the hydrocarbon liquids that condense during the processing of hydrocarbon gases that are produced from oil or gas reservoir; see also natural gasoline. Natural gasoline is a mixture of liquid hydrocarbons extracted from natural gas suitable for blending with refinery gasoline. Natural hydrocarbon gases are a mixture of saturated hydrocarbon type СnН2n+2. The main component – methane, CH4. Natural gasoline plant is a plant for the extraction of fluid hydrocarbon, such as gasoline and liquefied petroleum gas, from natural gas. Neutralization – is a decrease of neutralization of exhaust gases with the help of devices installed in the engine’s exhaust system. Negative catalyst – see inhibitor. Nitric acid HNO3 is one of the main products of large-tonnage chemistry; it is produced in the form of 60-65% aqueous solution. It refers to strong acids. It is a strong oxidizing agent, interacts with all metals except gold and platinum metals; some metals do not interact with HNO3 due to their passivation. Nitric acid is obtained from ammonia in the following reactions: 4NH3 + O2 = 4NO + 6H2O, 2NO +O2 = 2NO2, 4NO2 + O2 +2H2O = 4HNO3. Nitric acid is used for the production of fertilizers, explosives and for other purposes. The noosphere is the new geological envelope of Earth created by human society on a scientific basis (according to ideas and conclusions of V.I. Vernadsky). Normal hydrocarbons are hydrocarbons of unbranched, linear structure of the chain. The NOx storage and reduction system (NSR) is a practical method for removing NOx in excess oxygen conditions. O Octane number is a measure of the detonation resistance of fuel, that is, the ability of the fuel to withstand self-ignition when compressed in the combustion
chamber of a gasoline engine. The number indicating the relative antiknock characterristics of gasoline. The name comes from the fact that in the conventional scale of detonation resistance the number 100 is assigned to a normal octane. Oil (petroleum) is an oily liquid, usually brown to almost black, less often brownish-red to light orange, with a specific odor. It is a mixture of hydrocarbons of methane, naphthenic and aromatic series with an admixture of (usually minor) sulfur, nitrogen and oxygen compounds. The specific gravity is seldom below 0.7 and above 1, fluctuating usually in the range 0.82-0.89. The low specific gravity of oils (light oils) can be due to both their chemical character – the predominant content of methane hydrocarbons and the fractional composition – high content of gasoline. Heavy oils have a high specific gravity due to the high content of asphalt-resinous substances, the predominance of cyclic structures in the structure of hydrocarbons and the low content of easily boiling fractions (the initial boiling point sometimes exceeds 200 ºC). The sulfur content of the oils is usually lower than 1%, but sometimes reaches 5 – 5.5%. The amount of paraffins varies from trace amounts to 10% or more. Oils with the high content of paraffin differ in the increased freezing temperatures (it is higher than 0 ºC also to + 20 ºC), oils with the low content of paraffin stiffen at temperatures sometimes below – 20 ºC. The maintenance of asphalt and resinous components and viscosity of heavy oil are, as a rule, above than that of light oil. Oil-bearing characteristics – 1) the direct separation of liquid oil, 2) the impregnation of rocks with oil; 3) deposits of solid bitumens (asphalt, ozocerite); 4) release of combustible gas; 5) the presence of mud volcanoes; 6) an oil or bituminous smell emitted by the rock, sometimes only after its strong heating; 7) coloring of the gasoline or benzene extract of the determined rock. Oil-bearing characteristics indicate the possible presence of oil in the rocks in the considered rocks of this area. Oil-bearing rocks are rocks impregnated with oil. Typically, oil impregnates well-porous rocks – sands, sandstones, fossilized limestones, etc., creating from such rocks the industrial-oil-bearing horizons to be developed. Oil-bearing rocks are also clays, etc., dense rocks, but the oil in them is dispersed and slightly concentrated only in bends and crushed parts. The oil-bearing region is a set of several adjacent genetically linked structures with signs of oil or a set of similar oil deposits with similar oil-bearing suites. Oil recovery is a degree of completeness of oil recovery. Oil reservoir is a layer of rock, more or less impregnated with oil. Oil saturation of layer is the amount of oil which is available in the layer in relation to the total volume of pores, cavities and cracks in the oil-containing rock. In natural conditions, oil saturates a small part of the pores, and the larger ones. Small pores, due to the action of surface tension forces, are occupied by water. The smaller the pores, the more «buried» water in the layer. In some layers, the amount of this water is quite significant – up to 40%. «Buried» water in the process of exploitation of the reservoir does not usually manifest itself, and the wells give waterless oil. Olefins – it is a family of unsaturated hydrocarbons with one carbon-carbon double bond and the general formula CnH2n.
Open pores are channels or cavities that communicate with the outer surface of the particle. Molecules from the surrounding space can freely penetrate into the open pores by diffusion. Oxidation catalysts are catalysts that provide a quick solution to lowering emissions. Conversion of carbon monoxide, hydrocarbons and aldehydes into H2O and CO2 are the result of an oxidation catalyst at work. Products of incomplete combustion – HC and CO – are oxidized in the exhaust system by a catalyst that creates CO2 (carbon dioxide) and H2O (water). Oxygenate is an oxygen-containing compound that is blended into gasoline to improve its octane number and to decrease gaseous emissions. Ozone «hole» is a significant space in the ozonosphere of the planet with a markedly (up to 50%) reduced ozone content. In 1985 – 1988 years ozone «holes» were recorded over Antarctica, Australia and the Arctic. Their anthropogenic origin is supposed, for example, freons (chlorofluorocarbons), oxides of sulfur and nitrogen, which are recognized as ozone destroyers. P Paraffins – it is a family of saturated aliphatic hydrocarbons (alkanes) with the general formula CnH2n+2. Paraffin waxes are saturated aliphatic hydrocarbons. These waxes are residues extracted when dewaxing lubricant oils. They have a crystalline structure which is more or less fine according to the grade. Their main characteristics are: they are colourless, odourless and translucent, with a melting point above 45 °C. Particle size distribution is a statistical distribution of the number of particles, depending on their size. It is determined by microscopic methods. Passivation is a method of protecting metal catalysts by means of a small controlled oxidation of the surface in an oxygen medium. The resulting oxide layer on the surface of metal particles prevents further oxidation of the metal. Particulate matter (PM), also known as particle pollution, is a complex mixture of extremely small particles and liquid droplets that get into the air. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. Petroleum (crude oil) is a naturally occurring mixture of gaseous, liquid, and solid hydrocarbon compounds usually found trapped deep underground beneath impermeable cap rock and above a lower dome of sedimentary rock such as shale; most petroleum reservoirs occur in sedimentary rocks of marine, deltaic, or estuarine origin. Petroleum coke is a black solid by-product, obtained mainly by cracking and carbonising petroleum-derived feedstock, vacuum bottoms, tar and pitches in such processes as delayed coking or fluid coking. It consists mainly of carbon (90% to 95%) and has a low ash content. It is used as a feedstock in coke ovens for the steel industry, for heating purposes, for electrode manufacture and for production of chemicals. Petroleum natural gases are gases consisting of a mixture of gaseous hydrocarbons of the paraffin series (СnН2n+2): methane CH4 (sometimes up to 99%),
ethane C2H6, propane C3H8, butane C4H10, with an admixture of nitrogen, carbon dioxide, hydrogen sulfide and gasoline vapors. They are subdivided into dry gases (with a predominance of methane) and fatty gases (with a high content of heavy hydrocarbons). Pitch is the nonvolatile, brown to black, semi-solid to solid viscous product from the destructive distillation of many bituminous or other organic materials, especially coal; it has also been incorrectly applied to residua from petroleum processes where thermal decomposition may not have occurred. The plasticizer is a substance that is introduced into the material to give it plastic properties. Plastics are materials based on natural or synthetic polymers, which, under the influence of heating and pressure, can be molded into products of complex configuration and then stably retain the given shape. The production of synthetic plastics is based on polymerization, polycondensation or polyaddition reactions of low molecular weight raw materials derived from coal, oil or natural gas, such as benzene, ethylene, phenol, acetylene and other monomers. In this case, high-molecular bonds are formed with a large number of initial molecules. Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. Platforming is a reforming process using a platinum-containing catalyst on an alumina base. Point pollution is the ratio of the average concentration of pollution to the average MAC. Poisoning is a decrease in the activity of the catalyst, which is caused by the interaction of the active sites of the catalyst with the catalytic poison present in the reaction mixture. There is reversible poisoning and irreversible poisoning. In reversible poisoning, the catalytic activity is restored to its original level after removal of the poison from the reaction mixture. In case of irreversible poisoning, for example, due to strong adsorption of the poison on the active centers of the catalyst, the catalytic activity remains low even after removal of the poison from the reaction mixture. In this case, the catalytic activity can be recovered by regenerating the catalyst, or by complete chemical processing of the poisoned catalyst. Pollution is the introduction into the land, water and air systems of a chemical or chemicals that are not indigenous to these systems or the introduction into the land, water and air systems of indigenous chemicals in greater than natural amounts. Pollution (environment or surrounding medium) is the occurrence, introduction into the environment of usually not characteristic physical, chemical, biological agents or their excess during the considered time in the natural background, often leading to negative consequences. Protection from pollution is ensured by a system of laws, rules and regulations, assessments of the impact of the projected facilities on the environment and environmental impact assessment. It is believed that the necessary protection against pollution is observed, if the maximum permissible concentration of harmful substances is not exceeded. Reducing pollution is an integral part of the sustainable development society model. To overcome, evaluate and predict pollution, environmental monitoring is used, a system of environmental standards such as MPC (MAC) is developed.
Pollution anthropogenic is pollution that has arisen as a result of people’s activities. Pollution of atmospheric air means emission into the air or formation in it of pollutants (particles of dust, smoke, acid droplets, exhaust combustion and automobile gases, etc.) in concentrations exceeding the hygienic and environmental quality standards for atmospheric air. The main polluters of air are industrial enterprises (the most toxic emissions are generated by the enterprises of non-ferrous and ferrous metallurgy, chemical, petrochemical industry), motor transport, heat and power engineering, agriculture. Pollution of atmospheric air leads to the destruction of the ozone layer, formation of smog, erosion of metal structures, cement stone and other building materials, causing degradation of ecosystems of soils and natural waters, increasing diseases of plants, animals, and the population. Pollution of the catalyst is blocking of the active centers of the catalyst by the mechanical impurity contained in raw materials. In case of the heterogeneous catalyst mechanical impurity can also block porous system in granules of the catalyst and, thus, reduce the degree of use of its surface. Pollutions organized are pollutions caused by investigation, drilling, production, transportation, processes of primary (separation) and secondary (conversion) oil refining. Pollution prevention is a process of reduction or prevention of generation of pollutants. For example, pollution prevention may include changing a manufacturing process so that pollutants are no longer generated or their amount is greatly reduced. Alternatively it may require the installation of equipment that removes the pollutant before it is emitted or discharged to the environment so that it can be disposed of in a more appropriate manner. Pollution score is the ratio of the average annual concentration of this pollution to the average daily MAC. Pollutions unorganized are pollutions caused by leakage of oil and oil products due to leakage of equipment, emergency emissions, accidents during transportation, oil spills during fountains from wells, seepage of hydrocarbons through soil into reservoirs and other unforeseen circumstances that may also arise during drilling, production, pumping oil at pumping stations, operation of processing, oil-loading and pipeline transport equipment, etc. Pores are cavities (emptiness) or channels in solid particles. It is commonly be-lieved that the depth of the pores exceeds their width. There are open pores and closed pores. Pore size distribution is the statistical distribution of pore volume, depending on their size in the material under study. It is determined experimentally by the results of porosimetry or by calculation methods (by the adsorption isotherm). The pore size distribution affects the diffusion of the reactants and products in the solidphase catalyst particles. The pore volume is the total volume of all pores present in the solid material. Porous structure of the substance is the structure of porous space, i.e. a spatial arrangement and the sizes of pores in substance particles. The predecessor is an initial or intermediate chemical compound which at the subsequent stages of synthesis passes into target substance.
The pressure of the beginning of condensation is the pressure at which condensate in a layer is released from the gas into a liquid. Primary particles are particles of the smallest size, which can be identified as independent discrete constituents of the substance. Since the resolution of methods can depend strongly on a particular sample, usually when specifying the primary particles, it is also necessary to indicate the identification method (for example, transmission or scanning electron microscopy). The production rate of a well is the amount of production that is obtained from a well in a unit of time. Oil always has as its companion the oil gas released from the oil when it leaves the surface. Therefore, one should distinguish oil production and gas production. Some wells produce oil with water, sometimes in the form of an emulsion. For these wells, the water production rate and the emulsion discharge are distinguished in addition to the oil and gas production rate. In oil field practice, oil, emulsion and water flow rates are usually measured in tons per day, and gas production in cubic meters per day. Sometimes the water flow rate is expressed as a percentage of all the liquid produced by the well. Production wastes are residues of raw materials, materials and semi-products formed in production and which have completely or partially lost their qualities. Semi-products, by-products and production wastes after or without additional processsing can be used as raw materials for other processes. Product quality is a combination of technical, operational, economic and other properties that determine its suitability for consumption. Product quality is measured in accordance with State Standards (SS) and technical specifications (TS) on products. Product yield is the relation of amount of the reagent which has turned into this product to the total of reagent given on a reactor entrance. The amount of reagent can be measured in various units (mol number, weight, etc.). Productivity (P) is the amount of the target product produced per unit of time, or the amount of raw materials processed per unit of time τ:
P = т/τ, where т is the amount of product produced in time τ. Productivity can be attributed both to a separate unit, and to the process line, workshop and enterprise as a whole. A promoter is a substance added in small amounts to a catalyst in order to improve its activity, selectivity or stability. At the same time, the improvement in the properties of the catalyst is much greater than that which could be obtained as a result of the independent action of the promoter itself. Promoters can be a variety of substances. There are textural promoters (have a physical effect on the catalyst) and structural promoters (change the chemical properties of the catalyst). Propane-propylene fraction is a mixture of gaseous hydrocarbons with the number of carbon atoms 3, formed in the course of catalytic cracking during oil processing. Proved reserves are mineral reserves that have been positively identified as recoverable with current technology. The pulse reactor is a flow reactor operating in a pulsed mode. It is used in laboratory studies to study fast processes. In a pulsed reactor, a carrier gas stream is
continuously fed through the catalyst, into which a stream of reagents is periodically added in the form of a short pulse. After each pulse, the reaction products can be analyzed, or the changes that have occurred to the catalyst are studied. The purity index is the ratio of the average daily MAC to the average annual concentration of this pollution. Pyrolysis is a thermal process of decomposition of hydrocarbon feedstock to produce ethylene, propylene, benzene, butadiene, hydrogen and a number of other products. Pyrolysis gasoline is a by-product from the manufacture of ethylene by steam cracking of hydrocarbon fractions such as naphtha or gas oil. R Raffinate is the product resulting from a solvent extraction process and consisting mainly of those components that are least soluble in the solvents. The product recovered from an extraction process is relatively free of aromatics, naphthenes, and other constituents that adversely affect physical parameters. Rain acid means all types of precipitation (rain, hail, snow), in which the pH