A coke oven waste gas and waste gas waste heat recovery and reuse system

Abstract

A coke oven raw gas and waste gas waste heat recovery and reuse system comprises a coke oven, a high-temperature waste heat boiler, a waste gas purification device, a steam turbine, an oil-gas separator, a low-temperature waste heat boiler, a gas cooler, an oil-water separator, and a low-temperature waste heat recovery device. The high-temperature waste heat boiler, the low-temperature waste heat boiler, and the low-temperature waste heat recovery device are simultaneously provided in the scheme, so as to realize the effective recovery and reuse of the high-temperature sensible heat of the raw gas, the low-temperature waste heat of the heavy tar, and the low-temperature waste heat of the 60-100°C raw gas, and also to recover the heavy tar and light tar existing in large quantities in the raw gas, so as to create profits and increase revenue for the enterprise, and has good economic and social benefits. The raw gas is also transported to a first flue gas pipeline for heat exchange with the coke oven waste gas in a second flue gas pipeline, so as to realize the partial recovery and reuse of the high-temperature sensible heat in the raw gas. In the process of denitrification of the coke oven waste gas, no additional heater is required, so as to greatly reduce the investment and treatment cost of the coke oven waste gas, and is beneficial to energy saving and consumption reduction of the coking enterprise.

Description

Technical Field

[0001] The invention relates to the technical field of coke oven waste heat recovery, and in particular to a coke oven raw gas and waste gas waste heat recovery and reuse system. Background Art

[0002] A coke oven contains dozens of carbonization chambers (e.g., 56), which produce a large amount of 600-800℃ raw gas during operation, which has high thermal energy. The process commonly used by coke ovens at home and abroad is to collect the raw gas produced during the carbonization chamber distillation process into the top space of the carbonization chamber, and enter the gas collecting pipe through the riser and bridge pipe. The raw gas is directly sprayed with ammonia water in the bridge pipe to cool it to about 85℃. The cooled raw gas contains a large amount of tar and other components, and the temperature is still high. It needs to undergo multiple treatments to become coke oven gas, which makes the cost of coke oven gas to produce natural gas (SNG, CNG, LNG) too high, and the natural gas products lack obvious competitiveness. This process not only wastes a large amount of sensible heat of thermal energy in the raw gas, but also wastes light tar, heavy tar and other components with high economic value in the raw gas.

[0003] Coke ovens produce a large amount of raw coal gas as well as a large amount of coke oven exhaust gas. After the exhaust gas passes through the exhaust gas switch, its temperature is about 220-280℃, while the applicable temperature of the most mature catalytic reduction denitrification (SCR) catalyst is 300-400℃. If the coke oven exhaust gas is directly introduced into the denitrification tower, its low temperature leads to low efficiency of catalytic reduction denitrification and cannot meet the flue gas emission requirements. Therefore, coking enterprises usually set up a heater to heat the coke oven exhaust gas, and then send it into the SCR denitrification tower after heating it to above 300℃. During the denitrification process, not only can the heat energy in the coke oven exhaust gas not be recovered, but also additional heat energy must be added to the coke oven exhaust gas to make it meet the denitrification requirements, which increases the investment and treatment costs of coking enterprises' coke oven exhaust gas. Summary of the invention

[0004] In view of this, in order to address the above-mentioned shortcomings, it is necessary to propose a coke oven raw gas and waste gas waste heat recovery and reuse system.

[0005] A coke oven raw gas and waste gas waste heat recovery and reuse system, comprising a coke oven, a high-temperature waste heat boiler, a waste gas purification device, a steam turbine, an oil-gas separator, a low-temperature waste heat boiler, a gas cooler, an oil-water separator, and a low-temperature waste heat recovery device, wherein the coke oven raw gas outlet is connected to the first inlet of the high-temperature waste heat boiler, the coke oven waste gas outlet is connected to one end of the waste gas purification device, the other end of the waste gas purification device is connected to the third inlet of the refrigerant evaporator, the first outlet of the high-temperature waste heat boiler is connected to the first inlet of the oil-gas separator, one end of the steam turbine is connected to the second outlet of the high-temperature waste heat boiler, and the other end of the steam turbine is connected to the heat exchanger The second inlet of the oil-gas separator is connected, the first outlet of the oil-gas separator is connected to the first inlet of the gas cooler, the second inlet and outlet of the oil-gas separator are connected to the first inlet of the low-temperature waste heat boiler, the first outlet of the low-temperature waste heat boiler is connected to the second inlet of the oil-gas separator, the second outlet of the low-temperature waste heat boiler is connected to the second inlet of the high-temperature waste heat boiler, the third outlet of the low-temperature waste heat boiler is connected to the heavy tar storage tank, the first outlet of the gas cooler is connected to the first inlet of the oil-water separator, the first outlet of the oil-water separator is connected to the third inlet of the oil-gas separator, and the second outlet of the oil-water separator is connected to the light tar storage tank The second outlet of the oil-water separator is connected to the ammonia water tank, one end of the low-temperature waste heat recovery device is connected to the second outlet of the gas cooler, and the other end of the low-temperature waste heat recovery device is connected to the second inlet of the low-temperature waste heat boiler. The exhaust gas purification device includes a denitration tower, a desulfurization tower, and a glass fiber bag dust collector. One end of the denitration tower is connected to the exhaust gas outlet of the coke oven, one end of the desulfurization tower is connected to the other end of the denitration tower, one end of the glass fiber bag dust collector is connected to the other end of the desulfurization tower, and the other end of the glass fiber bag dust collector is connected to the third inlet of the refrigerant evaporator. The low-temperature waste heat recovery device includes a refrigerant evaporator, a vapor-liquid separator, and a compressor machine, heat exchanger, and hot water storage, the first inlet of the refrigerant evaporator is connected to the second outlet of the gas cooler, the first outlet of the refrigerant evaporator is connected to the coke oven gas tank, the third outlet of the refrigerant evaporator is connected to the external chimney, one end of the vapor-liquid separator is connected to the second outlet of the refrigerant evaporator, one end of the compressor is connected to the other end of the vapor-liquid separator, the first inlet of the heat exchanger is connected to the other end of the compressor, the first outlet of the heat exchanger is connected to the second inlet of the refrigerant evaporator, the first inlet of the hot water storage is connected to the second outlet of the heat exchanger, and the first outlet of the hot water storage is connected to the second inlet of the low-temperature waste heat boiler.

[0006] Preferably, a condenser is further provided between the steam turbine and the heat exchanger.

[0007] Preferably, a deaerator is further provided between the first outlet of the hot water storage device and the second inlet of the low-temperature waste heat boiler, and the hot water storage device is further provided with a second outlet.

[0008] Preferably, a first regulating valve is also provided on the flue connecting the coke oven raw gas outlet end with the first inlet of the high-temperature waste heat boiler, and a second regulating valve is also provided on the pipeline connecting the first inlet of the refrigerant evaporator with the second outlet of the gas cooler.

[0009] Preferably, a first temperature sensor is also provided on the pipe connecting the first inlet of the refrigerant evaporator and the second outlet of the gas cooler, and a second temperature sensor is also provided on the pipe connecting the first outlet of the refrigerant evaporator and the coke oven gas tank.

[0010] Preferably, a first flue gas pipe is further arranged on the flue between the coke oven raw gas outlet end and the first inlet of the high-temperature waste heat boiler, a first air inlet is arranged at one end of the first flue gas pipe, a first air outlet is arranged at the other end of the first flue gas pipe, a second flue gas pipe is further arranged on the flue connected with the coke oven exhaust gas outlet end at one end of the denitration tower, both ends of the second flue gas pipe are sealed, the second flue gas pipe is arranged in the first flue gas pipe, the axis of the second flue gas pipe coincides with the axis of the first flue gas pipe, and a second flue gas pipe is arranged on one side of the end of the second flue gas pipe Two air inlets, a second air outlet is arranged on the other side of the end of the second smoke duct, and a plurality of horizontal fixing plates and vertical fixing plates are arranged between the first smoke duct and the second smoke duct, one end of the horizontal fixing plate is arranged on the inner wall of the first smoke duct, and the other end of the horizontal fixing plate is arranged on the outer wall of the second smoke duct, one end of the vertical fixing plate is arranged on the inner wall of the first smoke duct, and the other end of the vertical fixing plate is arranged on the outer wall of the second smoke duct, and the horizontal fixing plates and the vertical fixing plates are staggered along the axial direction of the first smoke duct.

[0011] Preferably, the horizontal fixing plate includes an upper left fixing plate and a right fixing plate, and the left fixing plate and the right fixing plate are staggered along the axial direction of the first flue gas duct; the vertical fixing plate includes an upper fixing plate and a lower fixing plate, and the upper fixing plate and the lower fixing plate are staggered along the axial direction of the first flue gas duct.

[0012] Preferably, a plurality of heat absorbing units are further provided inside the second smoke duct, one end of the heat absorbing unit is provided on the inner wall of the second smoke duct and contacts the other ends of the upper fixing plate, the lower fixing plate, the left fixing plate and the right fixing plate, the other end of the heat absorbing unit extends into the second smoke duct, the heat absorbing unit comprises a connecting plate and a tilting piece, one end of the connecting plate contacts the other ends of the upper fixing plate, the lower fixing plate, the left fixing plate and the right fixing plate in the inner wall of the second smoke duct, and a plurality of tilting pieces are provided on the upper and lower surfaces of the connecting plate.

[0013] Preferably, the flap is a plate-fin flap, a tube-fin flap, or a spiral flap.

[0014] Preferably, a heat-insulating layer is also provided on the outer wall of the first flue gas duct.

[0015] This plan also sets up a high-temperature waste heat boiler, a low-temperature waste heat boiler, and a low-temperature waste heat recovery device, which realizes the full recovery and reuse of the high-temperature sensible heat and low-temperature waste heat of the raw coal gas, effectively reducing the waste of thermal energy resources of the raw coal gas. At the same time, the recovered superheated steam will drive the steam turbine to generate electricity, effectively saving the company's electricity costs, further reducing the cost of coke production, and improving the competitiveness of coke products. It also realizes precise control of the coke oven gas temperature, which helps to significantly reduce the subsequent production cost of coke oven gas to natural gas and improve the competitiveness of natural gas products.

[0016] This scheme can also recover the low-temperature waste heat of heavy tar and separate it by setting up a low-temperature waste heat boiler, and most of the heavy tar is transported to the heavy tar storage tank as a by-product. By setting up an oil-water separator, light tar and ammonia water can be separated, and most of the light tar is transported to the light tar storage tank as a by-product. This scheme can not only realize the recovery of high-temperature sensible heat of raw gas, low-temperature waste heat of heavy tar, 60-100℃ low-temperature waste heat of raw gas, and superheated steam power generation, but also recover the heavy tar and light tar in large quantities in the raw gas. The recovered heavy tar and light tar become by-products of the coking enterprise, creating profits and increasing revenue for the enterprise, and have good economic benefits.

[0017] This solution is provided with a first flue gas pipeline on the flue between the coke oven raw gas outlet and the first inlet of the high-temperature waste heat boiler, and a second flue gas pipeline is also provided on the flue connected to the coke oven exhaust gas outlet at one end of the denitrification tower, and the raw gas is transported to the first flue gas pipeline for heat exchange with the coke oven exhaust gas in the second flue gas pipeline, on the one hand, the high-temperature sensible heat of the raw gas is reduced, and on the other hand, the coke oven exhaust gas in the second flue gas pipeline absorbs part of the high-temperature sensible heat in the raw gas, and its temperature reaches the requirement for efficient denitrification of the coke oven exhaust gas. By setting up the first flue gas pipeline and the second flue gas pipeline at the same time, the partial recovery and reuse of the high-temperature sensible heat in the raw gas is realized. In the process of denitrification of the coke oven exhaust gas, there is no need to set up another heater, which reduces the process links of the coke oven exhaust gas treatment, greatly reduces the investment and treatment costs of the coke oven exhaust gas, and is beneficial to energy saving and consumption reduction of coking enterprises, and reduces the operating costs of coking enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the coke oven raw gas and exhaust gas waste heat recovery and reuse system.

[0019] Figure 2 It is a longitudinal cross-sectional view of the first flue gas duct and the second flue gas duct.

[0020] Figure 3 It is a transverse cross-sectional view of the first flue gas duct and the second flue gas duct.

[0021] In the figure: coke oven 10, first regulating valve 11, first flue gas duct 12, first air inlet 121, first air outlet 122, horizontal fixing plate 123, left fixing plate 1231, right fixing plate 1232, vertical fixing plate 124, upper fixing plate 1241, lower fixing plate 1242, insulation layer 125, second flue gas duct 13, second air inlet 131, second air outlet 132, heat absorption unit 133, connecting plate 1331, warping plate 13 32. High-temperature waste heat boiler 20, steam turbine 30, condenser 31, oil-gas separator 40, low-temperature waste heat boiler 50, gas cooler 60, second regulating valve 61, first temperature sensor 62, oil-water separator 70, refrigerant evaporator 81, second temperature sensor 811, gas-liquid separator 82, compressor 83, heat exchanger 84, hot water storage tank 85, deaerator 851, denitrification tower 91, desulfurization tower 92, glass fiber bag dust collector 93. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] See also Figures 1 to 3The present invention provides a coke oven raw gas and waste gas waste heat recovery and reuse system, comprising a coke oven 10, a high-temperature waste heat boiler 20, a steam turbine 30, an oil-gas separator 40, a low-temperature waste heat boiler 50, a gas cooler 60, an oil-water separator 70, and a low-temperature waste heat recovery device. The raw gas outlet end of the coke oven 10 is connected to the first inlet of the high-temperature waste heat boiler 20 to transport a large amount of 600-800°C raw gas in the coke oven 10 to the high-temperature waste heat boiler 20, so that the water in the high-temperature waste heat boiler 20 is heated and vaporized to generate 4-25MPa superheated steam, and the raw gas temperature is reduced to 300-450°C. The waste gas outlet end of the coke oven 10 is connected to one end of the waste gas purification device, and the other end of the waste gas purification device is connected to the refrigerant evaporator 81. The three inlets are connected, the first outlet of the high-temperature waste heat boiler 20 is connected to the first inlet of the oil-gas separator 40, so as to transport the raw gas of 300-450°C to the oil-gas separator 40, one end of the steam turbine 30 is connected to the second outlet of the high-temperature waste heat boiler 20, so as to transport the superheated steam to the steam turbine 30, and the superheated steam drives the steam turbine 30 to generate electricity. After the steam turbine 30 generates electricity, the process steam becomes the exhaust steam of 30-70°C, the other end of the steam turbine 30 is connected to the second inlet of the heat exchanger 84, so as to transport the exhaust steam to the heat exchanger 84, so as to exchange heat between the exhaust steam and the high-temperature and high-pressure gaseous refrigerant medium transported by the compressor 83, and tar is sprayed in the oil-gas separator 40 to separate the heavy tar from the raw gas, and the temperature of the heavy tar is 13 0~240℃, still has high thermal energy, and reduces the temperature of raw gas from 300~450℃ to 180~260℃, the first outlet of the oil-gas separator 40 is connected to the first inlet of the gas cooler 60, so as to transport the raw gas after heavy tar removal to the gas cooler 60, the second inlet and outlet of the oil-gas separator 40 is connected to the first inlet of the low-temperature waste heat boiler 50, so as to transport the heavy tar to the low-temperature waste heat boiler 50, the heavy tar is separated after heat exchange with water in the low-temperature waste heat boiler 50, the water in the low-temperature waste heat boiler 50 is heated and vaporized to generate superheated steam of 0.1~3MPa, the first outlet of the low-temperature waste heat boiler 50 is connected to the second inlet of the oil-gas separator 40, so as to transport a small part of the heavy tar to the oil-gas separator 40 In the embodiment, the low temperature waste heat boiler 50 is used for spraying raw gas. The second outlet of the low temperature waste heat boiler 50 is connected to the second inlet of the high temperature waste heat boiler 20 to transport the superheated steam of 0.1-3 MPa to the high temperature waste heat boiler 20. The third outlet of the low temperature waste heat boiler 50 is connected to the heavy tar storage tank to transport most of the heavy tar by-products to the heavy tar storage tank. Ammonia water is sprayed in the gas cooler 60 to reduce the temperature of the raw gas from 180-260°C to 60-100°C to separate the light tar from the raw gas. The first outlet of the gas cooler 60 is connected to the first inlet of the oil-water separator 70 to transport the light tar and ammonia water mixture to the oil-water separator 70. The oil-water separator 70 separates the light tar and ammonia water mixture.The first outlet of the oil-water separator 70 is connected to the third inlet of the oil-gas separator 40 to transport a small part of the light tar to the oil-gas separator 40 for spraying the raw gas. The second outlet of the oil-water separator 70 is connected to the light tar storage tank to transport most of the light tar by-products to the light tar storage tank. The second outlet of the oil-water separator 70 is connected to the ammonia water pool to transport the separated ammonia water to the ammonia water pool for recycling by the gas cooler 60 to reduce the cost of ammonia water. One end of the low-temperature waste heat recovery device is connected to the second outlet of the gas cooler 60, and the other end of the low-temperature waste heat recovery device is connected to the second inlet of the low-temperature waste heat boiler 50. The exhaust gas purification device includes a denitrification tower 91, a desulfurization tower 92, and a glass fiber bag dust collector. The denitrification tower 91 is connected to the exhaust gas outlet of the coke oven 10 at one end, and the denitrification tower 91 removes NOx from the exhaust gas of the coke oven. The desulfurization tower 92 is connected to the other end of the denitrification tower 91 at one end, and the desulfurization tower 92 removes SOx from the exhaust gas of the coke oven. The glass fiber bag filter 93 is connected to the other end of the desulfurization tower 92 at one end, and the glass fiber bag filter 93 removes dust particles from the exhaust gas of the coke oven. At this time, the temperature of the exhaust gas of the coke oven is 100-200°C, and it still has low-temperature waste heat. The other end of the glass fiber bag filter 93 is connected to the third inlet of the refrigerant evaporator 81 to transport the exhaust gas of the coke oven with low-temperature waste heat to the refrigerant evaporator 81. The refrigerant medium in the refrigerant evaporator 81 exchanges heat with the exhaust gas of the coke oven to reduce the temperature of the exhaust gas of the coke oven. The temperature of the raw coal gas is reduced from 100-200°C to 20-60°C to become waste gas. The low-temperature waste heat recovery device includes a refrigerant evaporator 81, a vapor-liquid separator 82, a compressor 83, a heat exchanger 84, and a hot water storage device 85. The first inlet of the refrigerant evaporator 81 is connected to the second outlet of the gas cooler 60 to transport the raw coal gas of 60-100°C to the refrigerant evaporator 81. The refrigerant medium in the refrigerant evaporator 81 exchanges heat with the raw coal gas to reduce the temperature of the raw coal gas from 60-100°C to 20-40°C to become coke oven gas. The first outlet of the refrigerant evaporator 81 is connected to the coke oven gas tank to transport the coke oven gas to the coke oven gas tank. The third outlet of the refrigerant evaporator 81 is connected to the external chimney to transport the waste gas to In the external chimney, the coke oven exhaust gas is discharged in compliance with the standards. One end of the vapor-liquid separator 82 is connected to the second outlet of the refrigerant evaporator 81 to separate the vaporized refrigerant from the liquid. One end of the compressor 83 is connected to the other end of the vapor-liquid separator 82 to transport the gaseous refrigerant to the compressor 83. The compressor 83 compresses the gaseous refrigerant into a high-temperature and high-pressure gaseous refrigerant. The first inlet of the heat exchanger 84 is connected to the other end of the compressor 83 to exchange heat between the high-temperature and high-pressure gaseous refrigerant and the exhaust steam in the heat exchanger 84. After absorbing heat, the exhaust steam becomes hot water at 80-100°C. The first outlet of the heat exchanger 84 is connected to the second inlet of the refrigerant evaporator 81 to transport the refrigerant whose temperature is reduced after heat exchange to the refrigerant evaporator 81.For circulation, the first inlet of the hot water storage tank 85 is connected to the second outlet of the heat exchanger 84 to transport the hot water to the hot water storage tank 85, and the first outlet of the hot water storage tank 85 is connected to the second inlet of the low-temperature waste heat boiler 50 to transport the hot water to the low-temperature waste heat boiler 50.

[0024] The present invention is provided with a high-temperature waste heat boiler 20, a low-temperature waste heat boiler 50, and a low-temperature waste heat recovery device. The high-temperature waste heat boiler 20 fully recovers the high-temperature sensible heat in the 600-800°C raw gas, so that the water in the high-temperature waste heat boiler 20 is heated and vaporized to generate 4-25MPa superheated steam, which is transported to the steam turbine 30 for power generation, and the raw gas temperature is reduced to 300-450°C. The low-temperature waste heat boiler 50 fully recovers the heavy gas of 130-240°C separated by the oil-gas separator 40. The low-temperature waste heat of tar causes the heavy tar to be separated after heat exchange with water in the low-temperature waste heat boiler 50. The water in the low-temperature waste heat boiler 50 is heated and vaporized to produce superheated steam of 0.1-3MPa. The low-temperature waste heat recovery device fully recovers the low-temperature waste heat of 60-100°C raw gas, converting the raw gas into 20-40°C coke oven gas. At the same time, the exhaust steam / cooling water exchanges heat with the high-temperature and high-pressure gaseous refrigerant medium in the heat exchanger 84, so that the exhaust steam / cooling water absorbs heat and becomes 80-100°C hot water. By simultaneously setting the high-temperature waste heat boiler 20, the low-temperature waste heat boiler 50, and the low-temperature waste heat recovery device, the high-temperature sensible heat and low-temperature waste heat of the raw gas are fully recovered and reused, effectively reducing the waste of raw gas thermal energy resources. At the same time, the recovered superheated steam drives the steam turbine 30 to generate electricity, effectively saving the enterprise's electricity costs.

[0025] In this scheme, the water used in the heat exchanger 84, hot water storage 85, low-temperature waste heat boiler 50, high-temperature waste heat boiler 20, and steam turbine 30 is arranged in a circulation manner. The high-temperature waste heat boiler 20 generates superheated steam, which drives the steam turbine 30 to generate electricity and then becomes exhaust steam / cooling water. The exhaust steam / cooling water is transported to the heat exchanger 84 and heat-exchanged with the high-temperature and high-pressure gaseous refrigerant medium to become hot water. The hot water is transported to the low-temperature waste heat boiler 50 to generate 0.1-3MPa superheated steam, and then the superheated steam is transported to the high-temperature waste heat boiler 20 to generate 4-25MPa superheated steam. In the process of water circulation, water resources are fully utilized, effectively reducing water costs. At the same time, the hot water in the hot water storage tank 85 is first transported to the low-temperature waste heat boiler 50, and the low-temperature waste heat boiler 50 heats the hot water to generate superheated steam. Compared with directly heating cold water, the low-temperature waste heat boiler 50 has a higher utilization rate of the waste heat of heavy tar and generates a higher pressure of superheated steam. The superheated steam of 0.1-3MPa is then transported to the high-temperature waste heat boiler 20 for heat exchange with 600-800℃ raw coal gas, which can generate higher pressure superheated steam. The high-temperature waste heat boiler 20 can generate 4-25MPa superheated steam under a lower workload, which greatly improves the utilization rate of the high-temperature sensible heat of 600-800℃ raw coal gas by the high-temperature waste heat boiler 20.

[0026] This solution sets a low-temperature waste heat boiler 50 to recover the low-temperature waste heat of the heavy tar and then separate it. A small part of the heavy tar is transported to the oil-gas separator 40 for spraying raw gas, and most of the heavy tar is transported to the heavy tar storage tank as a by-product. By setting an oil-water separator 70, the light tar and ammonia water are separated, a small part of the light tar is transported to the oil-gas separator 40 for spraying raw gas, and most of the light tar is transported to the light tar storage tank as a by-product. This scheme can not only realize the recovery of high-temperature sensible heat of raw coal gas, low-temperature waste heat recovery of heavy tar, 60-100℃ low-temperature waste heat recovery of raw coal gas, and superheated steam power generation, but also recover the heavy tar and light tar existing in large quantities in the raw coal gas. The recovered heavy tar and light tar become by-products of the coking enterprise, which can create profits and increase revenue for the enterprise, have good economic benefits, and can also greatly reduce the workload of the subsequent coke oven gas to natural gas purification section for processing heavy tar and light tar, effectively reducing the processing cost of the subsequent sections.

[0027] In this scheme, a first flue gas duct 12 is arranged on the flue between the raw gas outlet end of the coke oven 10 and the first inlet of the high-temperature waste heat boiler 20, and a second flue gas duct 13 is arranged on the flue connected to the coke oven exhaust gas outlet end at one end of the denitrification tower 91. The second flue gas duct 13 is arranged in the first flue gas duct 12. The raw gas in the first flue gas duct 12 has a large amount of raw gas and high high-temperature sensible heat, and the coke oven exhaust gas in the second flue gas duct 13 has a large amount of waste heat. The raw gas is transported to the first flue gas duct 12 for heat exchange with the coke oven exhaust gas in the second flue gas duct 13. On the one hand, the high-temperature sensible heat of the raw gas is reduced, such as reducing its temperature by about 100°C, so as to reduce the maintenance cost of the raw gas high-temperature resistant flue gas duct. On the other hand, the coke oven exhaust gas in the second flue gas duct 13 absorbs part of the high-temperature sensible heat in the raw gas and increases its temperature to between 300-400°C, thereby allowing the coke oven exhaust gas to meet the requirements of efficient denitrification. By simultaneously setting up the first flue gas duct 12 and the second flue gas duct 13, part of the high-temperature sensible heat in the raw gas is recovered, and the recovered heat is transferred to the coke oven exhaust gas in the second flue gas duct 13, so that the temperature of the coke oven exhaust gas rises to 300-400°C, thereby realizing the recovery and reuse of the heat of the raw gas. In the process of denitrification of the coke oven exhaust gas, there is no need to set up an additional heater, which reduces the subsequent treatment process links of the coke oven exhaust gas, greatly reduces the investment and treatment costs of the coke oven exhaust gas, and is beneficial to energy conservation and consumption reduction of coking enterprises, and reduces the operating costs of coking enterprises.

[0028] Specifically, the first inlet of the refrigerant evaporator 81 is connected to the second outlet of the gas cooler 60 to transport the 60-100°C raw gas to the refrigerant evaporator 81. The third inlet of the refrigerant evaporator 81 is connected to the other end of the glass fiber bag filter 93 to transport the 100-200°C coke oven exhaust gas to the refrigerant evaporator 81. Two independent gas delivery chambers are respectively arranged in the refrigerant evaporator 81, and the two sides of the refrigerant evaporation pipe are respectively arranged in the two independent gas delivery chambers, so that the raw gas and the coke oven exhaust gas are mixed with the refrigerant in the refrigerant evaporator 81. The medium performs heat exchange independently, and the refrigerant evaporator 81 can absorb the low-temperature waste heat of the raw coal gas and the coke oven exhaust gas at the same time, and then convert the recovered low-temperature waste heat into hot water through the subsequent heat exchanger 84, and the hot water is then transported to the production line for recycling. Through the above settings, it is possible to effectively avoid a large amount of low-temperature waste heat in the raw coal gas and the coke oven exhaust gas from escaping into the atmosphere, and a large amount of low-temperature waste heat in the raw coal gas and the coke oven exhaust gas can be recovered and reused, which greatly increases the heat utilization rate of the raw coal gas and the coke oven exhaust gas, and converts it into hot water for recycling in subsequent work sections, which has good economic benefits.

[0029] Furthermore, a condenser 31 is provided between the steam turbine 30 and the heat exchanger 84 to reduce the temperature of the exhaust steam and condense the exhaust steam into cooling water at a temperature of 15-30°C.

[0030] Specifically, the cooling water temperature is lower than the exhaust steam. When exchanging heat with the high-temperature and high-pressure gaseous refrigerant medium in the heat exchanger 84, it can absorb more heat from the high-temperature and high-pressure gaseous refrigerant medium under the same conditions, so that the temperature of the refrigerant medium returned to the refrigerant evaporator 81 for circulation is lower, which can further increase the refrigerant medium's heat absorption capacity for raw coal gas, thereby significantly reducing the temperature of the raw coal gas after passing through the refrigerant evaporator 81, that is, controlling the temperature of the coke oven gas at 20-40°C.

[0031] As the raw gas for producing natural gas, coke oven gas needs to undergo a variety of subsequent process treatments, but the temperature of the coke oven gas at the inlet is required to be at a relatively low temperature. However, in the actual production process, conventional processes such as water spraying are often used, which causes the coke oven gas temperature at the inlet to be often greater than 50°C, resulting in an increase in the production cost of subsequent processes and making it difficult to meet production needs.

[0032] This scheme converts the exhaust steam into cooling water by setting up a condenser 31, and then transports the cooling water to the heat exchanger 84 for heat exchange with the high-temperature and high-pressure gaseous refrigerant medium, so that the temperature of the coke oven gas is maintained at 20-40°C, which can greatly reduce the workload of the refrigerant evaporator 81 and effectively reduce the operating cost of the low-temperature waste heat recovery device. At the same time, by increasing the workload of the condenser 31, the cooling water temperature can be reduced to a lower level, such as 5-10°C, and then the cooling water at this temperature can be transported to the heat exchanger 84 for heat exchange with the high-temperature and high-pressure gaseous refrigerant medium, which can further reduce the coke oven gas temperature, such as to 10-20°C, which is beneficial to increase the use range of the temperature at the coke oven gas inlet and effectively reduce the subsequent coke oven gas to natural gas processing costs.

[0033] Furthermore, a deaerator 851 is provided between the first outlet of the hot water storage tank 85 and the second inlet of the low-temperature waste heat boiler 50 to remove free oxygen in the hot water and ensure that the free oxygen entering the circulating water circuit of the steam turbine 30 does not exceed the standard. The hot water storage tank 85 is also provided with a second outlet to transport the hot water to other hot water usage locations in the plant, such as the methane chemical section, heating pipelines, etc., to reduce the cost of other hot water usage locations in the plant.

[0034] Furthermore, a first regulating valve 11 is provided on the flue connecting the raw gas outlet of the coke oven 10 and the first inlet of the high-temperature waste heat boiler 20 , and a second regulating valve 61 is provided on the pipeline connecting the first inlet of the refrigerant evaporator 81 and the second outlet of the gas cooler 60 .

[0035] Specifically, the first temperature sensor 62 monitors the temperature of the raw gas at the first inlet of the refrigerant evaporator 81, and compares the raw gas temperature with the preset temperature: when the raw gas temperature is not less than the preset temperature, the first regulating valve 11 is not adjusted; when the raw gas temperature is less than the preset temperature, it means that the raw gas flow rate output from the raw gas outlet of the coke oven 10 is too low, or the workload of the high-temperature waste heat boiler 20 is too high, and the raw gas flow rate output from the coke oven 10 is increased by adjusting the first regulating valve 11, thereby increasing the raw gas flow rate to the high-temperature waste heat boiler 20. The total inflow amount is adjusted so that more raw gas is transported to the high-temperature waste heat boiler 20 to release heat without adjusting the working load of the high-temperature waste heat boiler 20, the oil-gas separator 40 and the gas cooler 60, so that the temperature of the raw gas at the first inlet of the refrigerant evaporator 81 is increased to a preset temperature; or by reducing the working load of the high-temperature waste heat boiler 20 and reducing the degree of heat exchange of the raw gas by the high-temperature waste heat boiler 20, the temperature of the raw gas at the first inlet of the refrigerant evaporator 81 is increased to a preset temperature without adjusting the flow rate of the raw gas output by the coke oven 10.

[0036] Specifically, the second temperature sensor 811 monitors the temperature of the coke oven gas and compares the coke oven gas temperature with the preset temperature: when the coke oven gas temperature is lower than the preset temperature, the second regulating valve 61 is not adjusted; when the coke oven gas temperature is not lower than the preset temperature, it indicates that the raw gas flow rate in the refrigerant evaporator 81 is too high, or the workload of the refrigerant evaporator 81 is too low. By adjusting the second regulating valve 61, the raw gas flow rate delivered to the refrigerant evaporator 81 is reduced, and the total amount of raw gas delivered to the refrigerant evaporator 81 is reduced. Without adjusting the workload of the refrigerant evaporator 81, the refrigerant medium in the refrigerant evaporator 81 fully exchanges heat with the limited raw gas, thereby causing the coke oven gas temperature to drop to the preset temperature; or by increasing the workload of the refrigerant evaporator 81, the degree of heat exchange of the refrigerant evaporator 81 with the raw gas is increased, and without adjusting the raw gas flow rate, the coke oven gas temperature is dropped to the preset temperature.

[0037] By providing the first regulating valve 11 and the first temperature sensor 62, the temperature of the raw gas at the first inlet of the refrigerant evaporator 81 is precisely controlled; by providing the second regulating valve 61 and the second temperature sensor 811, the temperature of the coke oven gas is precisely controlled; while ensuring full recovery and reuse of the waste heat of the raw gas, the temperature of the coke oven gas can also be controlled within an appropriate range, which helps to significantly reduce the subsequent production cost of natural gas from coke oven gas and enhance the competitiveness of natural gas products.

[0038] Furthermore, a first temperature sensor 62 is provided on the pipe connecting the first inlet of the refrigerant evaporator 81 and the second outlet of the gas cooler 60 to detect the temperature of the raw gas at the first inlet of the refrigerant evaporator 81, and a second temperature sensor 811 is provided on the pipe connecting the first outlet of the refrigerant evaporator 81 and the coke oven gas tank to detect the temperature of the coke oven gas.

[0039] Furthermore, a first flue gas duct 12 is also arranged on the flue between the raw gas outlet end of the coke oven 10 and the first inlet of the high-temperature waste heat boiler 20. The first flue gas duct 12 is a rigid corrosion-resistant hollow cylinder. A first air inlet 121 is arranged at one end of the first flue gas duct 12 to be connected to the flue gas duct in the upper half between the raw gas outlet end of the coke oven 10 and the first inlet of the high-temperature waste heat boiler 20. A first air outlet 122 is arranged at the other end of the first flue gas duct 12 to be connected to the flue gas duct in the lower half between the raw gas outlet end of the coke oven 10 and the first inlet of the high-temperature waste heat boiler 20. A second flue gas duct 13 is also arranged on the flue where one end of the denitrification tower 91 is connected to the exhaust gas outlet end of the coke oven. The second flue gas duct 13 is a rigid corrosion-resistant heat-conductive hollow cylinder with sealed ends. The second flue gas duct 13 is arranged in the first flue gas duct 12, and the axis of the second flue gas duct 13 coincides with the axis of the first flue gas duct 12 A second air inlet 131 is provided at one side of the end of the second flue gas duct 13 to transport the coke oven exhaust gas in the exhaust gas outlet end of the coke oven 10 to the second flue gas duct 13, and a second air outlet 132 is provided at the other side of the end of the second flue gas duct 13 to transport the coke oven exhaust gas heated in the second flue gas duct 13 to the denitrification tower 91. A plurality of horizontal fixing plates 123 and vertical fixing plates 124 are provided between the first flue gas duct 12 and the second flue gas duct 13, one end of the horizontal fixing plate 123 is provided on the inner wall of the first flue gas duct 12, and the other end of the horizontal fixing plate 123 is provided on the outer wall of the second flue gas duct 13, one end of the vertical fixing plate 124 is provided on the inner wall of the first flue gas duct 12, and the other end of the vertical fixing plate 124 is provided on the outer wall of the second flue gas duct 13, and the horizontal fixing plates 123 and the vertical fixing plates 124 are staggered along the axial direction of the first flue gas duct 12.

[0040] Furthermore, the horizontal fixing plate 123 includes a left fixing plate 1231 and a right fixing plate 1232, and the left fixing plate 1231 and the right fixing plate 1232 are staggered along the axial direction of the first flue gas duct 12; the vertical fixing plate 124 includes an upper fixing plate 1241 and a lower fixing plate 1242, and the upper fixing plate 1241 and the lower fixing plate 1242 are staggered along the axial direction of the first flue gas duct 12.

[0041] Specifically, the upper fixed plate 1241, the lower fixed plate 1242, the left fixed plate 1231, and the right fixed plate 1232 have the same structure and are staggered along the axial direction of the first flue gas duct 12. The setting direction is perpendicular to the raw gas transportation direction, so as to slow down the flow velocity of the raw gas in the first flue gas duct 12 and form local turbulence, thereby extending the flow distance of the raw gas in the first flue gas duct 12, thereby increasing the contact time between the raw gas and the second flue gas duct 13, increasing the heat exchange between the raw gas in the first flue gas duct 12 and the coke oven exhaust gas in the second flue gas duct 13, and promoting the temperature increase of the coke oven exhaust gas in the second flue gas duct 13; at the same time, it can also increase the contact time between the raw gas and the horizontal fixed plate 123 and the vertical fixed plate 124, so that the horizontal fixed plate 123 and the vertical fixed plate 124 absorb more heat in the raw gas, so as to transfer more heat to the connecting plate 1331 inside the second flue gas duct 13.

[0042] Preferably, the upper fixed plate 1241 is a copper plate having excellent thermal conductivity, and can effectively absorb the high-temperature sensible heat in the raw coal gas in the first flue gas duct 12 to transfer more heat to the coke oven exhaust gas in the second flue gas duct 13, thereby improving the thermal conductivity of the raw coal gas in the first flue gas duct 12 and the coke oven exhaust gas in the second flue gas duct 13, and effectively increasing the temperature of the coke oven exhaust gas.

[0043] Further, a plurality of heat absorbing units 133 are further arranged inside the second flue gas duct 13, one end of the heat absorbing unit 133 is arranged on the inner wall of the second flue gas duct 13 and contacts with the other ends of the upper fixing plate 1241, the lower fixing plate 1242, the left fixing plate 1231 and the right fixing plate 1232, and the other end of the heat absorbing unit 133 extends into the second flue gas duct 13, the heat absorbing unit 133 comprises a connecting plate 1331 and a tilting piece 1332, the shape of the connecting plate 1331 matches the shape of the upper fixing plate 1241, the lower fixing plate 1242, the left fixing plate 1231 and the right fixing plate 1232, and the size is consistent, preferably, the connecting plate 1331 is a copper plate, One end of the connecting plate 1331 is in contact with and fixed to the inner wall of the second flue gas duct 13 with the other ends of the upper fixing plate 1241, the lower fixing plate 1242, the left fixing plate 1231, and the right fixing plate 1232, so that the heat absorbed by the upper fixing plate 1241, the lower fixing plate 1242, the left fixing plate 1231, and the right fixing plate 1232 can be directly transferred to the connecting plate 1331, so that the coke oven exhaust gas in the second flue gas duct 13 can be fully heat exchanged with the upper fixing plate 1241, the lower fixing plate 1242, the left fixing plate 1231, and the right fixing plate 1232. A number of flaps 1332 are evenly arranged on the upper and lower surfaces of the connecting plate 1331 to improve the heat exchange efficiency of the coke oven exhaust gas.

[0044] Specifically, when the raw coal gas in the first flue gas duct 12 and the coke oven exhaust gas in the second flue gas duct 13 are heat exchanged, the thermal conductivity of the second flue gas duct 13 is limited due to the influence of the material and mechanics of the second flue gas duct 13, and the temperature of the coke oven exhaust gas can be increased, but the heating efficiency is relatively limited, and it is difficult to make the temperature of the coke oven exhaust gas reach the requirement of 300-400°C after the heat exchange. In this solution, a plurality of upper fixing plates 1241, lower fixing plates 1242, left fixing plates 1231, and right fixing plates are alternately arranged between the first flue gas duct 12 and the second flue gas duct 13. Plate 1232, and a plurality of connecting plates 1331 are also arranged on the inner wall of the second flue gas duct 13, and a plurality of tilting pieces 1332 are also arranged on the connecting plates 1331, and the upper fixing plate 1241, the lower fixing plate 1242, the left fixing plate 1231, the right fixing plate 1232 and the connecting plate 1331 are in contact with and fixed in the pipe wall of the second flue gas duct 13, so as to achieve consistency in heat conduction efficiency between the raw coal gas in the first flue gas duct 12 and the coke oven exhaust gas in the second flue gas duct 13, and effectively improve the temperature of the coke oven exhaust gas in the second flue gas duct 13.

[0045] Furthermore, the flaps 1332 are plate-fin flaps, tube-fin flaps, or spiral flaps to enhance the heat absorption capacity and heat exchange efficiency of the connecting plate 1331 .

[0046] Furthermore, a heat-insulating layer 125 is provided on the outer wall of the first flue gas duct 12 to prevent the high-temperature heat in the first flue gas duct 12 from escaping to the external environment, thereby improving the utilization rate of the high-temperature sensible heat of the raw gas.

[0047] The modules or units in the device of the embodiment of the present invention may be combined, divided or deleted according to actual needs.

[0048] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A coke oven waste gas and waste gas waste heat recovery and reuse system, characterized by: The invention comprises a coke oven, a high-temperature waste heat boiler, an exhaust gas purification device, a steam turbine, an oil-gas separator, a low-temperature waste heat boiler, a gas cooler, an oil-water separator, and a low-temperature waste heat recovery device. The raw gas outlet of the coke oven is connected to the first inlet of the high-temperature waste heat boiler, the exhaust gas outlet of the coke oven is connected to one end of the exhaust gas purification device, the other end of the exhaust gas purification device is connected to the third inlet of the refrigerant evaporator, the first outlet of the high-temperature waste heat boiler is connected to the first inlet of the oil-gas separator, one end of the steam turbine is connected to the second outlet of the high-temperature waste heat boiler, the other end of the steam turbine is connected to the second inlet of the heat exchanger, and the oil-gas separator is connected to the second outlet of the high-temperature waste heat boiler. The first outlet of the gas cooler is connected to the first inlet of the gas cooler, the second inlet and outlet of the oil-gas separator is connected to the first inlet of the low-temperature waste heat boiler, the first outlet of the low-temperature waste heat boiler is connected to the second inlet of the oil-gas separator, the second outlet of the low-temperature waste heat boiler is connected to the second inlet of the high-temperature waste heat boiler, the third outlet of the low-temperature waste heat boiler is connected to the heavy tar storage tank, the first outlet of the gas cooler is connected to the first inlet of the oil-water separator, the first outlet of the oil-water separator is connected to the third inlet of the oil-gas separator, the second outlet of the oil-water separator is connected to the light tar storage tank, the second ... second inlet of the oil-water separator, the second outlet of the oil-water separator is connected to the light tar storage tank, the second outlet of the oil-water separator is connected to the second inlet of the oil-water separator. The outlet is connected to the ammonia pool, one end of the low-temperature waste heat recovery device is connected to the second outlet of the gas cooler, and the other end of the low-temperature waste heat recovery device is connected to the second inlet of the low-temperature waste heat boiler. The exhaust gas purification device includes a denitration tower, a desulfurization tower, and a glass fiber bag dust collector. One end of the denitration tower is connected to the outlet of the coke oven exhaust gas, one end of the desulfurization tower is connected to the other end of the denitration tower, one end of the glass fiber bag dust collector is connected to the other end of the desulfurization tower, and the other end of the glass fiber bag dust collector is connected to the third inlet of the refrigerant evaporator. The low-temperature waste heat recovery device includes a refrigerant evaporator, a vapor-liquid separator, a compressor, and a heat exchanger. , a hot water storage device, the first inlet of the refrigerant evaporator is connected to the second outlet of the gas cooler, the first outlet of the refrigerant evaporator is connected to the coke oven gas tank, the third outlet of the refrigerant evaporator is connected to the external chimney, one end of the vapor-liquid separator is connected to the second outlet of the refrigerant evaporator, one end of the compressor is connected to the other end of the vapor-liquid separator, the first inlet of the heat exchanger is connected to the other end of the compressor, the first outlet of the heat exchanger is connected to the second inlet of the refrigerant evaporator, the first inlet of the hot water storage device is connected to the second outlet of the heat exchanger, and the first outlet of the hot water storage device is connected to the second inlet of the low-temperature waste heat boiler.

2. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 1, characterized in that: A condenser is also arranged between the steam turbine and the heat exchanger.

3. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 1, characterized in that: A deaerator is further provided between the first outlet of the hot water storage device and the second inlet of the low-temperature waste heat boiler, and the hot water storage device is further provided with a second outlet.

4. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 1, characterized in that: A first regulating valve is also provided on the flue connecting the coke oven raw gas outlet end with the first inlet of the high-temperature waste heat boiler, and a second regulating valve is also provided on the pipeline connecting the first inlet of the refrigerant evaporator with the second outlet of the gas cooler.

5. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 1, characterized in that: A first temperature sensor is also provided on the pipeline connecting the first inlet of the refrigerant evaporator and the second outlet of the gas cooler, and a second temperature sensor is also provided on the pipeline connecting the first outlet of the refrigerant evaporator and the coke oven gas tank.

6. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 1, characterized in that: A first flue gas duct is also arranged on the flue between the coke oven raw gas outlet end and the first inlet of the high-temperature waste heat boiler, a first air inlet is arranged at one end of the first flue gas duct, and a first air outlet is arranged at the other end of the first flue gas duct, a second flue gas duct is also arranged on the flue connecting one end of the denitrification tower with the coke oven waste gas outlet end, both ends of the second flue gas duct are sealed, the second flue gas duct is arranged in the first flue gas duct, the axis of the second flue gas duct coincides with the axis of the first flue gas duct, a second air inlet is arranged on one side of the end of the second flue gas duct, and a second air outlet is arranged on the other side of the end of the second flue gas duct, a plurality of horizontal fixing plates and vertical fixing plates are arranged between the first flue gas duct and the second flue gas duct, one end of the horizontal fixing plate is arranged on the inner wall of the first flue gas duct, and the other end of the horizontal fixing plate is arranged on the outer wall of the second flue gas duct, one end of the vertical fixing plate is arranged on the inner wall of the first flue gas duct, and the other end of the vertical fixing plate is arranged on the outer wall of the second flue gas duct, and the horizontal fixing plates and the vertical fixing plates are staggered along the axis direction of the first flue gas duct.

7. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 6, characterized in that: The horizontal fixing plate includes an upper left fixing plate and a right fixing plate, and the left fixing plate and the right fixing plate are staggered along the axis direction of the first flue gas duct; the vertical fixing plate includes an upper fixing plate and a lower fixing plate, and the upper fixing plate and the lower fixing plate are staggered along the axis direction of the first flue gas duct.

8. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 6, characterized in that: A plurality of heat absorbing units are further arranged inside the second smoke duct, one end of the heat absorbing unit is arranged on the inner wall of the second smoke duct and contacts the other ends of the upper fixing plate, the lower fixing plate, the left fixing plate and the right fixing plate, the other end of the heat absorbing unit extends into the second smoke duct, the heat absorbing unit comprises a connecting plate and a tilting piece, one end of the connecting plate contacts the other ends of the upper fixing plate, the lower fixing plate, the left fixing plate and the right fixing plate in the inner wall of the second smoke duct, and a plurality of tilting pieces are arranged on the upper and lower surfaces of the connecting plate.

9. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 8, characterized in that: The flaps are plate-fin flaps, tube-fin flaps or spiral flaps.

10. The coke oven raw gas and waste gas waste heat recovery and reuse system as claimed in claim 6, characterized in that: A heat-insulating layer is also provided on the outer wall of the first flue gas duct.

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