It is urgent to promote the five major coking environmental protection technologies

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With the rapid development of the coking industry, coking pollution has put great pressure on the environment. Therefore, preventing and controlling environmental pollution has become an extremely urgent task for the coking industry. Here is a summary of several coking environmental protection technologies that urgently need to be promoted or further promoted. Five major coking technologies that are in urgent need of promotion 1. Coal moisture control technology Loading coal moisture control technology is referred to as coal moisture control. It is a technology that removes part of the moisture from coking coal before loading to keep the moisture of the loaded coal stable. Coal humidity control technology has received widespread attention for its significant energy saving, environmental protection and economic benefits, and has developed rapidly. The basic principle of coal drying and coal humidification is to use external heating energy to dry and dehydrate the coking coal materials outside the coke oven to reduce the moisture of the coal entering the furnace or to adjust the moisture of the coal entering the furnace, thereby shortening the coking time, reducing coking energy consumption and residual ammonia production, stabilizing coke oven operation, improving coke quality or expanding the amount of weakly caking coal. my country's first thermal kerosene drying coal humidity control device was implemented in my country's Chongqing Iron and Steel Coking Plant in 1996. Baosteel and Taigang Coking Plants are currently implementing the construction of coal humidity control devices using steam as the heat source. The techniques currently used for coal humidity control mainly include the following:: The multi-tube rotary drum dryer coal humidification process uses steam as the heat source, and the fluidized bed coal humidification process uses coke oven flue gas as the heat source. 2. Coal dust and coke dust control: 95% of large and medium-sized machinery and coke enterprises adopt closed coal transfer stations, crusher rooms, and coal transportation corridors to prevent coal dust from escaping and causing pollution. Measures such as pulse bag dust collectors in the pulverizer room, coke transportation and storage system transfer station and coke screening building have a dust removal efficiency of 99.5%, effectively controlling the escape of coal dust and coke dust, and the emission rate and concentration of each emission outlet can meet the emission standards. 3. The main technologies for coke oven smoke pollution control and coal loading dust removal in my country are: Non-combustion dry ground station dust removal technology, combustion dry ground station dust removal technology, non-combustion dry dust removal coal loading car technology (especially suitable for double collection tube coke ovens), coal loading and coke removal non-combustion two-in-one dry ground station dust removal technology. The ground station purification technology developed in coke removal and dust removal includes: Ground station dust removal technology is adopted in the form of reverse suction bag dust collector filtration, and ground station dust removal technology in the form of pulse bag dust collector with full online filtration and full offline dust cleaning is adopted. The technologies developed in the conduction method between the coking flue gas and the ground station include: The interface flap valve is connected to the conduction method, and the mobile trolley tape sealing conduction method is used. Automatic control is adopted for the system control of coal loading and coke discharge dust removal, and the operation of the dust removal system is mechanically interlocked with the corresponding coke oven. When smoke and dust are generated, the dust removal fan runs at high speed ； When no smoke and dust are generated, the dust removal fan runs at low speed, achieving true automatic adjustment, energy saving and production automation. About 45% of mechanical coke production is equipped with smoke and dust removal treatment facilities such as coke oven coal loading and dust removal ground stations, coke oven coke discharge dust removal ground stations, and dry coal loading and dust removal trucks. The smoke and dust collection rate of the coke oven coal loading and dust removal ground station and the coke oven coke discharge and dust removal ground station can reach more than 95%. The smoke and dust collection rate of the dry coal loading and dust removal vehicle smoke and dust removal treatment facilities can reach 85% and 90%. The smoke and dust removal purification rate of each smoke and dust removal can reach more than 99.5%. The main pollutants in the smoke and dust all meet the emission standards. The top sealing equipment and furnace doors of large and medium-sized mechanized coke ovens adopt new sealing structures, mechanical cleaning devices, and stable adjustment of gas collecting pipe pressure to reduce the amount of smoke and dust escaping outside the furnace by 90% to 95%. 4. Dry coke quenching technology Dry coke quenching has the advantages of energy saving, environmental protection and coke improvement. a) Recovery of sensible heat from red coke: Dry coke quenching recovers heat energy from red-hot coke to generate steam and generate electricity. Dry coke quenching can recover about 80% of the sensible heat of red coke. On average, more than 0.5t of 3.9MPa 450°C steam can be recovered for every ton of coke quenched. b) Reduce environmental pollution: When wet coke quenching is used, 0.5t of steam containing phenol, cyanide, sulfide and dust will be discharged into the air for every ton of red coke quenched. Dry coke quenching uses inert gas to quench red coke in a closed system and is equipped with good dust removal facilities, which basically does not pollute the environment. Dry coke quenching can produce steam (5t~6t of steam requires 1 ton of thermal coal), which can be used for power generation, and can avoid atmospheric pollution from boilers that produce the same amount of steam, especially reducing SO2 and CO2 emissions. For a coking plant with a scale of 1 million tons/a, the use of dry coke quenching can reduce atmospheric pollution caused by the combustion of thermal coal by 80,000 to 100,000 tons per year. c) Can improve coke quality: Dry coke quenching can improve the strength of coke, making the coke have good wear resistance, uniform block size, low coke powder content and low moisture content. These factors are conducive to reducing the ironmaking coke ratio and smooth blast furnace operation, thereby increasing the blast furnace production capacity. d) While maintaining the quality of the original coke, dry coke quenching can reduce the amount of highly cohesive coke and fat coal by 10% to 20%, which is beneficial to protecting resources and reducing coking costs. 5. Coking wastewater treatment technology Coking wastewater is one of the most difficult industrial wastewaters to treat. It has the characteristics of high concentration of pollutants, complex components and high hazards. High-concentration phenols, cyanides, petroleum, suspended solids, sulfides and other pollutants in coking sewage can all reach discharge standards after biochemical treatment. However, water pollution of CODcr and ammonia nitrogen has not yet been completely controlled. 5.1 Biological denitrification technology of coking sewage According to the different configurations of aerobic, anaerobic, anoxic and other reaction devices in the biological denitrification process, the biological denitrification process can be divided into A/O biological denitrification process, A/OO biological denitrification process, etc. a) A/O biological denitrification process A/O biological denitrification process is the earliest biological denitrification process for coking sewage developed and has been applied in various coking plants. The A/O biological denitrification process has the following characteristics:: Utilize the carbon source in raw sewage as electron donor during denitrification without adding external carbon source ； This process belongs to nitric acid type denitrification and denitrification, that is, the ammonia nitrogen in the sewage is directly oxidized to nitrate nitrogen in the O section, and then flows back to the A section for denitrification, so the process flow is short. ； The process operation is stable and management is convenient. b) A/OO biological denitrification process. This process has the following advantages:: The nitrification process is carried out separately from the nitrification process, and the nitrification liquid after nitrification is used for denitrification and denitrification. ； Denitrification still uses the carbon source in the raw sewage, but compared with the A/O process, denitrification can save 40% of the carbon source. When the C/N ratio is constant, the total nitrogen removal rate can be improved. ； Oxygen demand can be reduced by about 25%, and power consumption is low ； Alkali consumption can be reduced by about 20%, reducing processing costs ； The hydraulic retention time can be shortened and the reactor volume can also be reduced accordingly. ； The amount of sludge can be reduced by about 50%. 5.2 Catalytic wet oxidation technology is a method in which sewage is introduced into the air under high temperature, high pressure and maintained in a liquid state, and under the action of a catalyst, the pollutants are oxidized and decomposed more thoroughly, converting them into harmless substances, so that the sewage can be deeply purified. After the sewage is treated by catalytic wet oxidation, the soluble and suspended pollutants in the water are completely oxidized and decomposed, which can meet the requirements of deep purification. At the same time, the sewage can achieve the purpose of decolorization, deodorization and sterilization. Domestic and foreign tests have shown that after one-time catalytic wet oxidation of coking residual ammonia and Gumalon sewage, all indicators of the effluent can meet emission standards and meet reuse requirements. Since catalytic wet oxidation treatment starts directly from the one-step deep purification of high-concentration raw sewage in the process, compared with the traditional ammonia steaming and a series of treatments such as removal of phenol, pretreatment, biological denitrification, and coagulation, the treatment operation cost is roughly the same, but it is about 40% lower than activated carbon treatment. For high-concentration sewage with high COD value (10000-15000mg/l) and high ammonia nitrogen (4000-6000mg/l) and sewage that is difficult to biodegrade, such as Gumalon sewage, high-concentration coal gasification sewage, etc., the catalytic wet oxidation method should be used. my country's future direction of coking environmental protection management During the "Eleventh Five-Year Plan" period, the development principles of pollution prevention and control in the coking industry are: Adhere to the principles of comprehensive planning, overall consideration, and comprehensive management, and regard structural optimization, resource conservation, and environmental protection as a key task in the economic development process of the coking industry ； Adhere to the principle of harmonious unity of economic benefits, social benefits and environmental benefits ； Adhere to the self-development of enterprises and * * Promote the principle of integration at all levels * * Provide policy guidance and economic support for the prevention and control of pollution in the coking industry. The coking industry continues to enhance the self-discipline and self-development capabilities of enterprises through management innovation and technological innovation. 1. Large-scale coke ovens With the implementation of the "Steel Industry Policy" and "Coking Industry Access Conditions", enterprises will develop in the direction of large-scale and diversified operations. Eliminate those soil coke, improved coke, which are high energy consumption, low efficiency, serious pollution and waste of resources, and transform small machine coke. Independent coking plants will be gradually integrated and the scale of the enterprise will gradually increase. Coke ovens with a carbonization chamber height of 6 meters or above will become the dominant furnace type for coking production, and coke ovens with a carbonization chamber height of less than 4.3 meters will be gradually eliminated. Coking enterprises will achieve comprehensive environmental protection management, comprehensive utilization of resources and energy, and circular economic development. Based on China's national conditions, it is imperative to develop and design top-loading coke ovens above 6.5 meters and tamping coke ovens above 5.5 meters with independent intellectual property rights. Currently, my country's Yanzhou Mining Group, Taigang, Maanshan Iron and Steel, Wuhan Iron and Steel and Shougang Caofeidian are building 12 7.63-meter ultra-large volume coke ovens, three of which have been put into operation. Anshan Iron and Steel Co., Ltd. Bayuquan and Handan Iron and Steel Co., Ltd., Panzhihua Iron and Steel Co., Ltd. and Benxi Iron and Steel Co., Ltd. are building 10 large-volume coke ovens with a capacity of 6.98 meters. More than a dozen 5.5-meter tamped coke ovens and the world's tallest Tangshan Jiahua 6.25-meter tamped coke oven are also under construction. 2. Saving coking coal resources and energy-saving coal blending, coking technology and equipment will develop in the direction of saving coal resources, improving coke quality and protecting the environment. From the implementation of coal blending technology that predicts coke quality to the coal blending optimization expert system, furnace coal humidification technology and dry coke quenching environmental protection and energy saving technology with comprehensive benefits of environmental protection and energy saving will be further developed. All existing coke ovens in iron and steel enterprises are equipped with dry coke quenching devices, and coal humidity control technology and dry coke quenching environmental protection and energy-saving technology are vigorously promoted. 3. Actively carry out coking smoke and dust control, focusing on the development and promotion of smoke and dust control technologies in various coke oven production processes, improving the smoke and dust collection rate and purification rate, and reducing coke oven gas leakage. The key technologies developed include: High-temperature and high-concentration smoke pretreatment and dust removal and purification technology, coke oven machine side smoke control technology, tamped coke oven coal loading smoke control technology, and nitrogen oxide control technology. Key promotion technologies include: Dry quenching and dust removal purification technology, fully dry coal loading and coke removal dust removal ground station technology, coal loading and coke removal dust removal two-in-one ground station technology, sticky dust adsorption pre-spraying technology, dry dust removal coal loading truck technology and dust removal system special flue gas conversion valve application technology, furnace door, furnace frame, mechanized cleaning technology, furnace door high pressure water cleaning technology, mechanized opening and closing of the furnace cover and mechanized processing of head and tail coke and other clean production technologies. The matching rate of existing coke oven coal loading, coke extraction, smoke and dust removal devices has increased from the current 45% to 100%. 4. Promote technologically advanced gas purification, comprehensive gas utilization and chemical product recovery technologies and equipment to develop and promote technologically advanced, energy-saving and environmentally friendly industrial chain technologies that form a virtuous cycle. The key technologies developed include: New processes and technologies for gas desulfurization and decyanization, acid-making process technology from desulfurization waste liquid, optimized control technology for gas purification and chemical product recovery and refining systems. All existing coking enterprises have rebuilt or improved coke oven gas purification and utilization devices, and the coke oven gas desulfurization treatment compliance rate and coke oven gas recovery and utilization rate have reached 100%. 5. Comprehensively realize the discharge of coking sewage up to the standard. Coking sewage treatment focuses on the development and promotion of sewage treatment technology with high efficiency, low construction costs, low operating costs and space saving. The key technologies developed include: Coking sewage treatment reuse and "zero discharge" technology, application of MBR (membrane bioreactor) technology, ultrafiltration or nanofiltration membrane technology for advanced sewage treatment, efficient static mud-water separation technology, intelligent control mode of coking sewage treatment automatic detection technology, application of ozone, ultraviolet and other non-secondary pollution disinfection technology, high concentration phenol cyanide sewage wet catalytic oxidation purification treatment technology. The equipped coking wastewater treatment equipment (approximately 30%) without ammonia nitrogen removal function should be technologically transformed so that the coking wastewater treatment compliance rate reaches 100%, and the coking production industrial water reuse rate is increased from the current 80% to ≥95%. 6. Zero discharge of coking solid waste. The treatment of coking solid waste achieves zero discharge. On the basis of improving existing solid waste recycling technology, we will focus on developing tar residue, acid tar treatment technology, sludge treatment technology, desulfurization waste liquid and low-quality sulfur recycling technology, and coke oven treatment of waste plastics and waste tires to solve environmental pollution problems.