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INTRODUCTION
The purpose of this work is development of ways which optimize the process of catching of coking products. The improvement of economic and ecological indices in the departments of catching of chemical products at the Plants can be attained by means of installation of scrubbers Venturi for washing of coke gas with water-gum emulsion, eventual cooling of coke gas in heat-exchanger at irrigation with water-gum emulsion, cleaning of coke gas from hydrogen cyanide with water in the existing eventual gas refrigerators of shelf type with subsequent decyanidation of circulating water in the regenerators of absorptive solution of desulphurization departments. ANALYSIS OF MODEL CHART OF CATCHING OF CHEMICAL PRODUCTS OF COKING The model chart of catching of coking products, realized at the most of by-product plants of Ukraine, foresees the primary cooling of gas, cleaning from vapor-phase gum in electric separators, compression in the gas blower, absorption of ammonia in carbonators, eventual cooling of gas, absorption of ammonia with sulphuric acid with the production of raw benzol, gas cleaning from the hydrogen sulphide. Considerable difficulties in work of departments of catching of chemical products of coking are related to placing of cleaning process from sulphur at the end of the chart. The presence of hydrogen cyanide in coke gas causes intensive corrosion of pipelines and apparatus, creation of cracks and, as a result, losses of chemical products, their ingress in the atmosphere or ingress of air in the apparatus of regeneration departments working under vacuum. Hydrogen cyanide and oxygen promote the creation of cleaning from sulphur of the unregenerated salts in absorptive solution. To delete these salts it is necessary to remove part of solution in dumps, and to compensate losses at the additional discharge of soda. At the by-product coke plants with the open water cycle of eventual gas refrigerators considerable amount of hydrogen cyanide dissolves in water, and then it is given off in the atmosphere. It worsens sharply the ecological situation and causes corrosion of fabricated metals in adjoining territory. Closing of water cycle of eventual refrigerators is hardly realized in existing conditions because of blocking up aquatic refrigerators with naphthalene and resin and, in addition, does not provide the effective solution of problem of harmful effluent, because it results in the increase of amount of liquid waste in the workshops of desulfurization and in benzol sections. The presence of hydrogen cyanide, naphthalene and resinous matters in coke gas hampers the work of sulfate section, worsens quality of ammonium sulfate, and promotes the formation of sour resin. Low degree of utilization of the second sources of heat, large discharge of technical water and considerable volume of industrial sewages, belong to the disadvantages of existing technology. The approach of sewages dephenolization used at by-products coke plants is ineffective and uneconomical. Thus, the "classic" chart of catching of chemical products of coking, which is popular at by-products coke plants, does not provide the required cleaning of coke gas and production of high-quality products. It promotes formation of harmful liquid waste and gas effluents in the atmosphere. Meantime only the change of the sequence of chemical products catching can provide a considerable economic and ecological effect as compared to the classic chart. In connection with the intensification of ecological situation and deficit of power resources in Ukraine, the choice of optimum chart of treatment of direct coke gas appears to be an important task. © DonNTU Anna Akhremenko 2009 |
