Coke-oven gas low-temperature purification system

Abstract

The utility model discloses a low-temperature purification system for coke-oven gas. The low-temperature purification system comprises a coke oven, a compressor, a cooling tower, a refined deoiler, a refined naphthalene remover, a filter, a cooling water heat exchanger, a wastewater stripping tower and a wastewater gas condensate storage tank, a water outlet of the wastewater stripping tower is communicated with an inlet of a wastewater gas condensate storage tank through a pipeline, an outlet of the wastewater gas condensate storage tank is communicated with a water replenishing port at the bottom of a cooling tower through a water replenishing pump, and a water outlet at the bottom of the cooling tower is communicated with a thermal medium inlet of a cooling water heat exchanger through a circulating pump; and a thermal medium outlet of the cooling water heat exchanger is communicated with a spray water inlet of the cooling tower through a pipeline. The method has the advantages that the coke-oven gas entering the cooling tower is sprayed and cooled by the waste water steam stripping condensate, so that the use amount of desalted water is reduced, and the treatment cost of the desalted water is saved. Meanwhile, the condensate amount of the steam stripping process of the wastewater sent to coking treatment is reduced, so that the water treatment cost is also saved, and the production cost and the operation burden of enterprises are reduced.

Description

Technical fields:

[0001] This utility model relates to the field of coke oven gas treatment technology, and in particular to a low-temperature purification system for coke oven gas. Background technology:

[0002] Coke oven gas mainly originates from coke ovens and is produced during the high-temperature dry distillation of coal at 900-1000℃ under air-isolated conditions. The lower heating value of coke oven gas is 16-18 MJ / Nm³. 3 Coke oven gas is a high-quality gaseous fuel with a wide range of applications. However, due to its complex composition, mainly containing combustible gases such as hydrogen (55-60%), methane (23-27%), and carbon monoxide (5-8%), as well as impurities such as tar, naphthalene, sulfides, and ammonia, it is highly flammable and explosive. A mixture with air is prone to explosion upon contact with an open flame. Furthermore, it contains toxic and harmful components such as carbon monoxide and hydrogen sulfide. Therefore, untreated coke oven gas cannot be used directly.

[0003] Currently, coke oven gas often requires multiple processing steps, specifically: first, it undergoes indirect or direct cooling to lower the temperature and remove some impurities; then, it is treated with dry or wet desulfurization and decyanation, ammonia stripping and acid washing to remove ammonia, oil washing and absorption to remove benzene, and cooling crystallization or adsorption to remove naphthalene. However, existing treatment methods have many problems. For example, when coke oven gas enters a cooling tower from the outlet of the compressor's intermediate-pressure cylinder and is sprayed with demineralized water to cool it down and wash away impurities, the cooling tower needs to be replenished with water after a period of operation. Currently, demineralized water is used to replenish the cooling tower, but due to the low pressure of the demineralized water, it is impossible to replenish the cooling tower, forcing the unit to be shut down for water replenishment, which seriously affects the continuity and efficiency of coke oven gas treatment. Utility Model Content:

[0004] In order to solve the above problems, the purpose of this utility model is to provide a low-temperature purification system for coke oven gas.

[0005] This utility model is implemented by the following technical solution:

[0006] A low-temperature purification system for coke oven gas includes a coke oven, a compressor, a cooling tower, a fine oil remover, a fine naphthalene remover, a filter, a cooling water heat exchanger, a wastewater stripping tower, and a wastewater gas condensate storage tank.

[0007] The coke oven gas outlet is connected to the inlet of the intermediate-pressure cylinder of the compressor via a pipeline. The outlet of the intermediate-pressure cylinder of the compressor is connected to the inlet of the cooling tower via a pipeline. The outlet of the cooling tower is connected to the inlet of the oil remover via a pipeline. The outlet of the oil remover is connected to the inlet of the naphthalene remover via a pipeline. The outlet of the naphthalene remover is connected to the inlet of the filter via a pipeline. The outlet of the filter is connected to the inlet of the high-pressure cylinder of the compressor via a pipeline. The outlet of the high-pressure cylinder of the compressor is connected to the inlet of the coke oven gas storage tank via a pipeline.

[0008] The outlet of the wastewater stripping tower is connected to the inlet of the wastewater gas condensate storage tank via a pipeline. The outlet of the wastewater gas condensate storage tank is connected to the water inlet at the bottom of the cooling tower via a water supply pump. The outlet at the bottom of the cooling tower is connected to the heat medium inlet of the cooling water heat exchanger via a circulating pump. The heat medium outlet of the cooling water heat exchanger is connected to the spray water inlet of the cooling tower via a pipeline.

[0009] Furthermore, the bottom outlets of the oil remover, the naphthalene remover, and the filter are all connected to the inlet of the wastewater tank via pipelines. The outlet of the wastewater tank is connected to the heat medium inlet of the wastewater heat exchanger via a pipeline, and the heat medium outlet of the wastewater heat exchanger is connected to the wastewater inlet of the coking and chemical production section via a pipeline.

[0010] Furthermore, a liquid level sensor is installed inside the cooling tower. The signal output terminal of the liquid level sensor is connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the signal input terminal of the water supply pump.

[0011] Furthermore, the outlet of the chilled water inlet pipeline is connected to the cold medium inlet of the cooling water heat exchanger via a chilled water pump, and the cold medium outlet of the cooling water heat exchanger is connected to the cooling water return pipeline.

[0012] The signal output terminal of the controller is also connected to the signal input terminal of the chilled water pump.

[0013] Furthermore, an air inlet temperature sensor is provided at the air inlet of the cooling tower, and a spray water flow regulating valve is provided at the spray water inlet of the cooling tower. The signal output terminal of the air inlet temperature sensor is connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the signal input terminal of the spray water flow regulating valve.

[0014] Furthermore, an intake pressure sensor and an intake flow regulating valve are respectively installed at the air inlet of the cooling tower, and an outlet shut-off valve is installed at the air outlet of the intermediate pressure cylinder of the compressor; the signal output terminal of the intake pressure sensor is connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the signal input terminals of the intake flow regulating valve and the outlet shut-off valve respectively.

[0015] Advantages of this utility model:

[0016] 1. Through the synergistic effect of the cooling tower, oil remover, naphthalene remover and filter, tar droplets, naphthalene and impurities in coke oven gas are effectively removed, achieving the purpose of purifying coke oven gas, ensuring safe and stable operation after the coke oven gas enters the compressor, extending the service life of the compressor and reducing equipment maintenance costs.

[0017] 2. By using wastewater stripping condensate to spray and cool the coke oven gas entering the cooling tower, the amount of demineralized water used was reduced, saving on demineralized water treatment costs. Simultaneously, the reduced amount of wastewater stripping condensate sent to coking plants also saved on water treatment costs, lowering the company's production costs and operational burden.

[0018] 3. Through the interlocking circuit control device, automatic monitoring and control of temperature, pressure, liquid level and equipment operating status are realized, which improves the automation level and operational stability of the system, reduces manual operation and intervention, reduces the risk of failure caused by human factors, and improves production efficiency and safety. Attached image description:

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the system connection in this embodiment;

[0021] Figure 2 This is a control principle diagram for this embodiment.

[0022] In the diagram: 1. Coke oven; 2. Compressor; 3. Cooling tower; 4. Fine oil remover; 5. Fine naphthalene remover; 6. Filter; 7. Cooling water heat exchanger; 8. Wastewater stripping tower; 9. Wastewater gas condensate storage tank; 10. Coke oven gas temporary storage tank; 11. Make-up water pump; 12. Circulation pump; 13. Wastewater tank; 14. Wastewater heat exchanger; 15. Coking chemical production section; 16. Chilled water inlet pipeline; 17. Cooling water return pipeline; 18. Chilled water pump; 19. Liquid level sensor; 20. Inlet air temperature sensor; 21. Inlet air pressure sensor; 22. Controller; 23. Spray water flow regulating valve; 24. Inlet air flow regulating valve; 25. Outlet air shut-off valve. Detailed implementation method:

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Example 1:

[0025] like Figure 1 , Figure 2 The coke oven gas low-temperature purification system shown includes a coke oven 1, a compressor 2, a cooling tower 3, a fine oil remover 4, a fine naphthalene remover 5, a filter 6, a cooling water heat exchanger 7, a wastewater stripping tower 8, and a wastewater gas condensate storage tank 9.

[0026] The coke oven gas outlet of coke oven 1 is connected to the inlet of the intermediate pressure cylinder of compressor 2 via a pipeline. The outlet of the intermediate pressure cylinder of compressor 2 is connected to the inlet of cooling tower 3 via a pipeline. The outlet of cooling tower 3 is connected to the inlet of the oil remover 4 via a pipeline. The outlet of oil remover 4 is connected to the inlet of the naphthalene remover 5 via a pipeline. The outlet of naphthalene remover 5 is connected to the inlet of filter 6 via a pipeline. The outlet of filter 6 is connected to the inlet of the high pressure cylinder of compressor 2 via a pipeline. The outlet of the high pressure cylinder of compressor 2 is connected to the inlet of coke oven gas storage tank 10 via a pipeline.

[0027] The outlet of the wastewater stripping tower 8 is connected to the inlet of the wastewater gas condensate storage tank 9 via a pipeline. The outlet of the wastewater gas condensate storage tank 9 is connected to the water supply inlet at the bottom of the cooling tower 3 via a water supply pump 11. The outlet at the bottom of the cooling tower 3 is connected to the hot medium inlet of the cooling water heat exchanger 7 via a circulating pump 12. The hot medium outlet of the cooling water heat exchanger 7 is connected to the spray water inlet of the cooling tower 3 via a pipeline. The outlet of the chilled water inlet pipeline 16 is connected to the cold medium inlet of the cooling water heat exchanger 7 via a chilled water pump 18. The cold medium outlet of the cooling water heat exchanger 7 is connected to the cooling water return pipeline 17.

[0028] The bottom outlets of the oil remover 4, the naphthalene remover 5, and the filter 6 are all connected to the inlet of the wastewater tank 13 via pipelines. The outlet of the wastewater tank 13 is connected to the heat medium inlet of the wastewater heat exchanger 14 via pipelines. The heat medium outlet of the wastewater heat exchanger 14 is connected to the wastewater inlet of the coking and chemical production section 15 via pipelines.

[0029] This embodiment also adds interlock control, specifically: a liquid level sensor 19 is installed in the cooling tower 3, an air inlet temperature sensor 20 is installed at the air inlet of the cooling tower 3, an air inlet pressure sensor 21 and an air inlet flow regulating valve 24 are installed at the air inlet of the cooling tower 3, a spray water flow regulating valve 23 is installed at the spray water inlet of the cooling tower 3, and an outlet shut-off valve 25 is installed at the outlet of the intermediate pressure cylinder of the compressor 2.

[0030] The signal output terminals of the liquid level sensor 19, the air intake temperature sensor 20, and the air intake pressure sensor 21 are all connected to the signal input terminal of the controller 22. The signal output terminal of the controller 22 is connected to the signal input terminals of the water replenishment pump 11, the chilled water pump 18, the spray water flow regulating valve 23, the air intake flow regulating valve 24, and the air outlet shut-off valve 25, respectively.

[0031] Job Description:

[0032] The coke oven gas produced by coke oven 1 is pressurized by the intermediate pressure cylinder of compressor 2, and the coke oven gas at 40℃ and 0.7MPa enters the lower part of cooling tower 3. Meanwhile, the wastewater stripping condensate produced by wastewater stripping tower 8 is pumped into the bottom of cooling tower 3 by makeup water pump 11 as circulating liquid. At the same time, circulating pump 12 is started to send the circulating liquid to the tube side of cooling water heat exchanger 7, where it exchanges heat with the 16℃ chilled water in the shell side. After the heat exchange, the temperature of the circulating liquid decreases and it is sent to the spray nozzle at the top of cooling tower 3 to spray and cool the coke oven gas. The cooled coke oven gas enters the bottom of the oil remover 4, where residual tar droplets are removed by the selective adsorption of the degreasing agent in the tower. The coke oven gas is then sent out from the top of the oil remover 4. Finally, the gas enters the bottom of the naphthalene removal unit 5, where activated carbon adsorbents further remove naphthalene from the coke oven gas. It then enters filter 6, where it undergoes liquid separation and dust filtration. Liquid impurities and circulating condensate from cooling tower 3 enter wastewater tank 13. After heat exchange and cooling in wastewater heat exchanger 14, the gas is discharged into coking and chemical production section 15 for further treatment. The clean coke oven gas discharged from filter 6 enters the high-pressure cylinder of compressor 2, ensuring the long-term safe and stable operation of compressor 2. The pressurized clean coke oven gas is then buffered in coke oven gas storage tank 10 for subsequent use.

[0033] To ensure the safe and stable operation of the system throughout the entire process, the following interlocking controls are implemented, including:

[0034] Temperature interlock control: An inlet air temperature sensor 20 is installed at the air inlet of cooling tower 3 to monitor the temperature of the coke oven gas entering cooling tower 3. When the temperature of the coke oven gas at the inlet of cooling tower 3 exceeds 45℃, the controller 22 controls the opening of the spray water flow regulating valve 23 to increase, thereby increasing the spray volume of wastewater stripping condensate to improve the cooling effect of cooling tower 3 on coke oven gas.

[0035] Pressure interlock control: An inlet pressure sensor 21 is installed at the inlet of cooling tower 3 to monitor the pressure of coke oven gas entering cooling tower 3. When the inlet pressure of cooling tower 3 exceeds 0.8MPa, the controller 22 controls the opening of the inlet flow regulating valve 24 to decrease, reducing the amount of coke oven gas entering; if the pressure continues to rise to 0.9MPa, the controller 22 interlocks and closes the outlet shut-off valve 25 of the intermediate pressure cylinder of compressor 2 to prevent excessive pressure from damaging cooling tower 3 and other equipment.

[0036] Liquid level interlock control: A liquid level sensor 19 is installed at the bottom of the cooling tower 3 to monitor the liquid level inside the cooling tower 3. When the liquid level at the bottom of the cooling tower 3 is detected to be lower than the preset minimum set value, the controller 22 interlocks and starts the water supply pump 11 to replenish the cooling tower 3 with wastewater gas condensate; if the liquid level continues to drop and falls below the preset danger level value, the controller 22 interlocks and stops the operation of the chilled water pump 18 to prevent the chilled water pump 18 from running dry and being damaged.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A low-temperature purification system for coke oven gas, characterized in that, This includes coke ovens, compressors, cooling towers, oil removers, naphthalene removers, filters, cooling water heat exchangers, wastewater stripping towers, and wastewater gas condensate storage tanks. The coke oven gas outlet is connected to the inlet of the intermediate-pressure cylinder of the compressor via a pipeline. The outlet of the intermediate-pressure cylinder of the compressor is connected to the inlet of the cooling tower via a pipeline. The outlet of the cooling tower is connected to the inlet of the oil remover via a pipeline. The outlet of the oil remover is connected to the inlet of the naphthalene remover via a pipeline. The outlet of the naphthalene remover is connected to the inlet of the filter via a pipeline. The outlet of the filter is connected to the inlet of the high-pressure cylinder of the compressor via a pipeline. The outlet of the high-pressure cylinder of the compressor is connected to the inlet of the coke oven gas storage tank via a pipeline. The outlet of the wastewater stripping tower is connected to the inlet of the wastewater gas condensate storage tank via a pipeline. The outlet of the wastewater gas condensate storage tank is connected to the water inlet at the bottom of the cooling tower via a water supply pump. The outlet at the bottom of the cooling tower is connected to the heat medium inlet of the cooling water heat exchanger via a circulating pump. The heat medium outlet of the cooling water heat exchanger is connected to the spray water inlet of the cooling tower via a pipeline.

2. The low-temperature purification system for coke oven gas according to claim 1, characterized in that, The bottom outlets of the oil remover, the naphthalene remover, and the filter are all connected to the inlet of the wastewater tank via pipelines. The outlet of the wastewater tank is connected to the heat medium inlet of the wastewater heat exchanger via a pipeline. The heat medium outlet of the wastewater heat exchanger is connected to the wastewater inlet of the coking and chemical production section via a pipeline.

3. The low-temperature purification system for coke oven gas according to claim 1, characterized in that, A liquid level sensor is installed inside the cooling tower. The signal output terminal of the liquid level sensor is connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the signal input terminal of the water supply pump.

4. The low-temperature purification system for coke oven gas according to claim 3, characterized in that, The outlet of the chilled water inlet pipeline is connected to the cold medium inlet of the cooling water heat exchanger via a chilled water pump, and the cold medium outlet of the cooling water heat exchanger is connected to the cooling water return pipeline. The signal output terminal of the controller is also connected to the signal input terminal of the chilled water pump.

5. The low-temperature purification system for coke oven gas according to claim 1, characterized in that, An air inlet temperature sensor is installed at the air inlet of the cooling tower, and a spray water flow regulating valve is installed at the spray water inlet of the cooling tower. The signal output terminal of the air inlet temperature sensor is connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the signal input terminal of the spray water flow regulating valve.

6. The low-temperature purification system for coke oven gas according to claim 1, characterized in that, An intake pressure sensor and an intake flow regulating valve are respectively installed at the air inlet of the cooling tower, and an outlet shut-off valve is installed at the air outlet of the intermediate pressure cylinder of the compressor; the signal output terminal of the intake pressure sensor is connected to the signal input terminal of the controller, and the signal output terminal of the controller is connected to the signal input terminals of the intake flow regulating valve and the outlet shut-off valve respectively.

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