Co-production system for treating coke oven gas

Abstract

The utility model relates to the technical field of coking combustible gas treatment, and particularly discloses a co-production system for treating coke oven gas, which comprises a cooling component, a gas inlet component and a gas outlet component, the separation assembly is communicated with the cooling assembly and is used for separating coke oven gas; nitrogen is continuously input into the nitrogen washing tower, the middle of the nitrogen washing tower is communicated with the gas phase outlet of the separation assembly, and hydrogen-rich gas is output from the top of the nitrogen washing tower; the top of the methane tower is communicated with the bottom of the nitrogen washing tower, and the middle of the methane tower is communicated with the liquid phase outlet of the separation assembly; the reboiler is used for heating liquid output from the bottom of the methane tower to obtain methane; the circulating cold supply assembly is used for providing a cold source for the cooling assembly; hydrogen and methane in the coke oven gas can be fully separated, the hydrogen and the methane can be conveniently used in production and manufacturing of various products, and compared with reburning of the coke oven gas singly, the utilization rate of the hydrogen and the methane can be effectively increased, and resource waste is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of coking combustible gas treatment, in particular to a cogeneration system for treating coke oven gas. Background Art

[0002] Coke oven gas refers to the combustible gas obtained when coking coal is dried at high temperature in the coking oven to produce coke and tar products. It is a by-product of coking products. The unpurified gas is called raw gas, and the purified gas is called clean gas (i.e. coke oven gas).

[0003] The hydrogen content in coke oven gas is as high as 54% to 59%, followed by methane. These gases have high recycling value and a wide range of uses. Traditionally, coke oven gas has been used as fuel gas or for power generation. However, in this utilization method, the supply and demand of coke oven gas is unbalanced, and the high-value-added H2 and CH4 are not properly utilized, resulting in a large amount of hydrogen and methane resources being wasted. Utility Model Content

[0004] In view of the above problems, the present invention provides a cogeneration system for treating coke oven gas, the purpose of which is to improve the utilization rate of hydrogen and methane resources.

[0005] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is as follows:

[0006] Provided is a cogeneration system for treating coke oven gas, comprising: a cooling assembly for staged cooling of the coke oven gas; a separation assembly connected to the cooling assembly for separating the coke oven gas; a nitrogen scrubber continuously fed with nitrogen, the middle portion of the nitrogen scrubber being connected to a gas phase outlet of the separation assembly, and the top of the nitrogen scrubber outputting hydrogen-rich gas; a methane tower, the top of the methane tower being connected to the bottom of the nitrogen scrubber, and the middle portion of the methane tower being connected to a liquid phase outlet of the separation assembly; a reboiler for heating liquid output from the bottom of the methane tower to obtain methane; and a circulating cooling assembly for providing a cold source to the cooling assembly.

[0007] Furthermore, the cooling assembly includes: at least three first heat exchangers, second heat exchangers and third heat exchangers connected in sequence.

[0008] Furthermore, the circulating cooling component includes: two compressors installed in sequence, which receive the refrigerant output by the cooling component and compress and cool it; a final-stage refrigerant separator, which receives the refrigerant output by the compressor, and the liquid-phase refrigerant obtained by the final-stage refrigerant separator is input into the first heat exchanger for supercooling and flows back to the compressor; the gas-phase refrigerant obtained by the final-stage refrigerant separator passes through the first heat exchanger and is condensed; a high-pressure refrigerant separator, which receives the gas-phase refrigerant output by the first heat exchanger, and the liquid-phase refrigerant obtained by the high-pressure refrigerant separator passes through the first heat exchanger and is input into the reboiler and flows back to the compressor; the gas phase obtained by the high-pressure refrigerant separator passes through the first heat exchanger and the second heat exchanger in sequence and flows back to the compressor.

[0009] Furthermore, the separation component comprises at least: at least two first separators and a second separator connected in sequence.

[0010] Furthermore, the system also includes a condenser and a condensation separator. The condenser is used to receive and condense the gas output from the top of the methane tower. The condensation separator is connected to the output end of the condenser, wherein the liquid obtained by the condensation separator is refluxed into the methane tower, and the gas obtained by the condensation separator is output through the cooling component.

[0011] Furthermore, nitrogen is also cooled by a cooling assembly; wherein, the nitrogen is divided into a first throttling nitrogen, a second throttling nitrogen and a third throttling nitrogen, the first throttling nitrogen is input into a nitrogen washing tower, the second throttling nitrogen is used to mix with hydrogen and output, and the third throttling nitrogen can be input into a condenser for cooling.

[0012] Furthermore, the bottom outlet of the methane tower is connected to a cooling assembly for supercooling the methane.

[0013] The beneficial effects of the present invention are as follows: in the present invention, the coke oven gas is cooled by a cooling assembly, separated and purified by a separation assembly, and then fed into a nitrogen scrubber. The nitrogen purifies the coke oven gas in the nitrogen scrubber to obtain hydrogen-rich gas. Furthermore, a reboiler is provided to heat the liquid at the bottom of the methane tower to obtain liquid methane. By using the present invention, the hydrogen and methane in the coke oven gas can be fully separated, making it easier to use the hydrogen and methane in the production of a variety of products. Compared to simply reburning the coke oven gas, the utilization rate of hydrogen and methane can be effectively improved, reducing resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the overall installation of the system provided in the embodiment of the present application.

[0015] Among them, 1. first heat exchanger; 2. second heat exchanger; 3. first separator; 4. third heat exchanger; 5. second separator; 6. nitrogen scrubber; 7. methane tower; 8. condenser; 9. condensation separator; 10. first throttle valve; 11. second throttle valve; 12. third throttle valve; 13. reboiler; 14. fourth throttle valve; 15. fifth throttle valve; 16. sixth throttle valve; 17. seventh throttle valve; 18. compressor; 19. interstage cooler; 20. final stage cooler; 21. final stage refrigerant separator; 22. eighth throttle valve; 23. high-pressure refrigerant separator; 24. ninth throttle valve; 25. tenth throttle valve. DETAILED DESCRIPTION

[0016] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0017] Reference Figure 1 As shown, an embodiment of the present application discloses a cogeneration system for treating coke oven gas, including: a cooling component for staged cooling of coke oven gas; a separation component connected to the cooling component to separate the coke oven gas; a nitrogen scrubber 6, which continuously inputs nitrogen, the middle of the nitrogen scrubber 6 is connected to the gas phase outlet of the separation component, and the top of the nitrogen scrubber 6 outputs hydrogen-rich gas; a methane tower 7, the top of the methane tower 7 is connected to the bottom of the nitrogen scrubber 6, and the middle of the methane tower 7 is connected to the liquid phase outlet of the separation component; a reboiler 13, which is used to heat the liquid output from the bottom of the methane tower 7 to obtain methane; and a circulating cooling component for providing a cold source to the cooling component.

[0018] In the present invention, the coke oven gas is cooled by a cooling component, separated and purified by a separation component, and then sent to a nitrogen washing tower 6. The coke oven gas in the nitrogen washing tower 6 is purified by nitrogen to obtain hydrogen-rich gas. In addition, by setting a reboiler 13 to heat the liquid at the bottom of the methane tower 7, liquid methane can be obtained.

[0019] By using the utility model, hydrogen and methane in coke oven gas can be fully separated, which is convenient for using hydrogen and methane in the production of various products. Compared with simply reburning coke oven gas, the utility model can effectively improve the utilization rate of hydrogen and methane and reduce the waste of resources.

[0020] Specifically, the cooling assembly includes: at least three sequentially connected first heat exchangers 1, second heat exchangers 2 and third heat exchangers 4, which fully heat and cool the coke oven gas to ensure subsequent normal production efficiency.

[0021] Specifically, the circulating cooling component includes: two compressors 18 installed in sequence, which receive the refrigerant output by the cooling component and compress and cool it; a final-stage refrigerant separator 21, which receives the refrigerant output by the compressor 18, and the liquid-phase refrigerant obtained by the final-stage refrigerant separator 21 is input into the first heat exchanger 1 for supercooling and flows back to the compressor 18; the gas-phase refrigerant obtained by the final-stage refrigerant separator 21 passes through the first heat exchanger 1 and is condensed; a high-pressure refrigerant separator 23, which receives the gas-phase refrigerant output by the first heat exchanger 1, and the liquid-phase refrigerant obtained by the high-pressure refrigerant separator 23 passes through the first heat exchanger 1 and is input into the reboiler 13, passes through the ninth throttle valve 24 and flows back to the compressor 18; the gas phase obtained by the high-pressure refrigerant separator 23 passes through the first heat exchanger 1, the second heat exchanger 2 and the tenth throttle valve 25 in sequence and flows back to the compressor 18.

[0022] It is worth mentioning that an interstage cooler 19 and a final stage cooler 20 are respectively installed at the outlet ends of the two compressors 18 for cooling the refrigerant; the liquid refrigerant is transported through the eighth throttle valve 22 .

[0023] Specifically, the separation assembly comprises at least: at least two first separators 3 and second separators 5 connected in sequence.

[0024] In the present invention, by setting up a circulating cooling component, a cold source can be continuously provided to the first heat exchanger 1 and the second heat exchanger 2 respectively, the coke oven gas is refrigerated in stages, and the workload of the third heat exchanger 4 can be reduced; in this embodiment, the first separator 3 is arranged between the second heat exchanger 2 and the third heat exchanger 4, and the second separator 5 is arranged between the third heat exchanger 4 and the nitrogen washing tower 6. The two separations can also prevent low-temperature freezing.

[0025] Specifically, the coke oven gas is cooled to about -167°C through the first heat exchanger 1 and the second heat exchanger 2 and enters the first separator 3 for gas-liquid separation. The gas phase separated by the first separator 3 is further condensed to about -182°C through the third heat exchanger 4 and enters the second separator 5 for gas-liquid separation. The gas phase separated by the second separator 5 is sent to the nitrogen scrubber 6, and the liquid phase separated by the second circulator is sent to the methane tower 7 through the second throttle valve 11.

[0026] Among them, the liquid phase outlet of the first separator 3 is connected to the first throttle valve 10, the second heat exchanger 2 and the methane tower 7 in sequence. The liquid phase obtained by the first separator 3 is pressurized and returned to the second heat exchanger 2 to exchange heat with the coke oven gas. After reheating, it is sent to the methane tower 7, which can reduce the heat exchange workload of the cold source in the second heat exchanger 2.

[0027] In this embodiment, the bottom of the nitrogen scrubber 6 is connected to the top of the methane tower 7 via the third throttle valve 12. Although the load of the condenser 8 is increased, the cost of the methane tower 7 can be effectively reduced.

[0028] In this embodiment, nitrogen is also cooled by the cooling component. The nitrogen is cooled by the first heat exchanger 1 and the second heat exchanger 2. The nitrogen passes through the third heat exchanger 4 and acts as a cold source in the third heat exchanger 4. The nitrogen is divided into a first throttled nitrogen, a second throttled nitrogen and a third throttled nitrogen. The first throttled nitrogen is input into the nitrogen washing tower 6, the second throttled nitrogen is used to mix with hydrogen to produce synthesis gas and output it, and the third throttled nitrogen can be input into the condenser 8 for cooling.

[0029] Specifically, in this embodiment, nitrogen (about 4 MPa) passes through the first heat exchanger 1, the second heat exchanger 2 and the third heat exchanger 4 in sequence, and after being supercooled to -188°C, the first throttled nitrogen passes through the fifth throttle valve 15 and is input into the top of the nitrogen scrubber 6 for coke oven gas purification. After the coke oven gas passes through the nitrogen scrubber 6, qualified hydrogen-rich gas is obtained at the top of the tower; the second-section nitrogen passes through the sixth throttle valve 16 and is mixed with the hydrogen-rich gas for nitrogen distribution, and refluxes through the third heat exchanger 4, which can also provide cooling for the third heat exchanger 4.

[0030] It is worth mentioning that when the second throttling nitrogen cannot meet the nitrogen distribution demand, the nitrogen output from the second heat exchanger 2 can also pass through the fourth throttling valve 14 and mix with the synthesis gas output from the third heat exchanger 4 stage, and then pass through the first heat exchanger 1 and the second heat exchanger 2 in sequence to exchange heat with the coke oven gas and be reheated to go to the synthetic ammonia process.

[0031] In some embodiments, the bottom outlet of the methane tower 7 is connected to a cooling assembly for supercooling the methane. The liquid methane output from the bottom of the methane tower 7 can be cooled by the third heat exchanger 4 and the second heat exchanger 2 before entering the LNG storage tank.

[0032] Furthermore, the system also includes a condenser 8 and a condenser separator 9. The condenser 8 is used to receive and condense the gas output from the top of the methane tower 7. The condenser separator 9 is connected to the output end of the condenser 8, wherein the liquid obtained by the condenser separator 9 is refluxed into the methane tower 7, and the gas obtained by the condenser separator 9 is output through the cooling component; wherein the third throttling nitrogen passes through the seventh throttle valve 17 to provide a cold source for the condenser 8.

[0033] In the present invention, the nitrogen scrubber 6 and the methane tower 7 are used to purify the synthesis gas and extract and liquefy the methane from the coke oven gas, which has low cold energy consumption, eliminates the need for a dehydrogenation tower, and simplifies the process.

[0034] By using the utility model, coke oven gas can be effectively utilized to produce methanol and co-produce natural gas, and liquid nitrogen can be used to wash coke oven gas to synthesize ammonia and synthesis gas and co-produce LNG and natural gas and co-produce hydrogen, etc.; product diversification can be achieved, the market adaptability of coke oven gas can be improved, and thus the economic benefits can be improved.

[0035] Those skilled in the art will appreciate that, although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the underlying inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Clearly, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to encompass such changes and modifications if they fall within the scope of the claims and equivalents of the present invention.

Claims

1. A cogeneration system for treating coke oven gas, characterized in that: include: Cooling assembly for staged cooling of coke oven gas; The separation component is connected to the cooling component to separate the coke oven gas; A nitrogen washing tower (6) is continuously supplied with nitrogen, the middle portion of the nitrogen washing tower (6) is connected to the gas phase outlet of the separation component, and the top of the nitrogen washing tower (6) outputs hydrogen-rich gas; A methane tower (7), wherein the top of the methane tower (7) is connected to the bottom of the nitrogen washing tower (6), and the middle of the methane tower (7) is connected to the liquid phase outlet of the separation component; A reboiler (13) is used to heat the liquid output from the bottom of the methane tower (7) to obtain methane; The circulating cooling component is used to provide a cold source to the cooling component.

2. The cogeneration system for treating coke oven gas according to claim 1, characterized in that: The cooling assembly comprises: at least three first heat exchangers (1), second heat exchangers (2) and third heat exchangers (4) connected in sequence.

3. The cogeneration system for treating coke oven gas according to claim 2, characterized in that: The cooling system includes: Two compressors (18) installed in sequence receive the refrigerant output by the cooling assembly and compress and cool it; The final refrigerant separator (21) receives the refrigerant output by the compressor (18). The liquid refrigerant obtained by the final refrigerant separator (21) is input into the first heat exchanger (1) for subcooling and then flows back to the compressor (18). The gaseous refrigerant obtained by the final refrigerant separator (21) passes through the first heat exchanger (1) and is condensed. The high-pressure refrigerant separator (23) receives the gaseous refrigerant output by the first heat exchanger (1). The liquid refrigerant obtained by the high-pressure refrigerant separator (23) passes through the first heat exchanger (1), is input into the reboiler (13), and flows back to the compressor (18); the gaseous phase obtained by the high-pressure refrigerant separator (23) passes through the first heat exchanger (1) and the second heat exchanger (2) in sequence, and flows back to the compressor (18).

4. The cogeneration system for treating coke oven gas according to claim 1, characterized in that: The separation assembly comprises at least two first separators (3) and second separators (5) connected in sequence.

5. The cogeneration system for treating coke oven gas according to claim 1, characterized in that: The invention also includes a condenser (8) and a condensation separator (9), wherein the condenser (8) is used to receive the gas output from the top of the methane tower (7) and condense it, and the condensation separator (9) is connected to the output end of the condenser (8), wherein the liquid obtained by the condensation separator (9) is refluxed into the methane tower (7), and the gas obtained by the condensation separator (9) is output through the cooling component.

6. The cogeneration system for treating coke oven gas according to claim 5, characterized in that: The nitrogen is also cooled by the cooling assembly; wherein the nitrogen is divided into a first throttling nitrogen, a second throttling nitrogen and a third throttling nitrogen, the first throttling nitrogen is input into the nitrogen washing tower (6), the second throttling nitrogen is used to mix with hydrogen and output, and the third throttling nitrogen can be input into the condenser (8) for cooling.

7. The cogeneration system for treating coke oven gas according to claim 1, characterized in that: The bottom outlet of the methane tower (7) is connected to a cooling assembly for supercooling the methane.

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