Purification device for coke oven gas and purification process thereof

Abstract

The invention provides a purification device for coke oven gas and a purification process thereof.The purification device comprises a water washing ammonia tower, the water washing ammonia tower is connected with an ammonia still, the ammonia still is connected with an ammonia water refining tower, the top of the water washing ammonia tower is connected with a normal-temperature methanol washing tower, the normal-temperature methanol washing tower is connected with an extraction tower, and the bottom of the extraction tower is connected with a methanol-water separation tower; the top of the methanol-water separation tower is connected with the methanol-water separation tower through a methanol-water separation tower top circulating pipeline; the top of the normal-temperature methanol washing tower is connected with the low-temperature methanol washing tower, a clean gas extraction pipeline is arranged at the top of the low-temperature methanol washing tower, a tower kettle of the low-temperature methanol washing tower is connected with the flash tower, the bottom of the flash tower is connected with the thermal regeneration tower, and the bottom of the thermal regeneration tower is connected with the middle upper part of the low-temperature methanol washing tower; the purification device is short in process, less in equipment investment, high in coke oven gas purification index and capable of being directly utilized; the method is free of waste liquid, waste residue and waste catalyst, environment-friendly and low in energy consumption.

Description

Technical Field

[0001] The present application relates to the technical field of chemical equipment, and in particular to a coke oven gas purification device and a purification process thereof. Background Art

[0002] Coke oven gas is an important by-product obtained during the coking process. One ton of coke produces 430-450 cubic meters of coke oven gas, which has great utilization value. Its composition is as follows: Figure 1 As shown, it mainly includes H2, CH4, CO, CO2, N4, C n H m , O2, but coke oven gas also contains many complex impurities, which affect its utilization. The main impurity composition is shown in the following table:

[0003]

[0004] Ammonia and benzene in the above impurities can be recycled as useful components. The traditional ammonia recovery method is to use sulfuric acid and ammonia to generate sulfur ammonia. A small part of the deamination process uses phosphoric acid to absorb ammonia and then distills it to generate liquid ammonia or ammonia water. These two processes have large investments and high production costs, and the deamination accuracy is not high. After deamination, the raw gas still contains 50 mg / m3 of ammonia. 3 , which leads to low product value; the traditional benzene removal process uses oil washing to remove benzene, which has large investment, high energy consumption, and low debenzenization accuracy. After debenzenization, the raw gas still contains 2-5 grams of benzene / m 3 , which not only requires subsequent deep purification, but also wastes benzene resources.

[0005] The core issue of recycling and utilizing useful components is desulfurization. The commonly used desulfurization methods for coke oven gas in the prior art are dry desulfurization and wet desulfurization. Dry desulfurization mainly uses a desulfurization catalyst synthesized from ferric hydroxide and other preparations to remove H2S from the gas. The regenerated desulfurizer can be reused. Dry desulfurization is mainly used for desulfurization of coke oven gas with a small gas volume or secondary desulfurization with high desulfurization accuracy. The wet desulfurization process uses a liquid desulfurizer to remove H2S and HCN from the coke oven gas. The commonly used wet desulfurization methods include the improved ADA method, naphthoquinone method, gum method, FRC method, TH method, HPF method, Large-scale coking enterprises usually adopt wet desulfurization, including PDS method, OPT method, complex iron method, and ammonia catalytic method. Wet desulfurization cannot remove organic sulfur, and inorganic sulfur can only be removed to 20 mg / cubic. The sulfur by-product of wet desulfurization is of poor quality and low value, and wet desulfurization inevitably produces side salts. In order to avoid the accumulation of side reaction salts in the desulfurization waste liquid, a small amount of waste liquid will be discharged. The previous measure was to send the discharged desulfurization waste liquid into the coal blending system, but this method will cause environmental problems and pollute the environment. At present, the treatment investment of desulfurization waste liquid is large, and although the treatment process seems to be recycling, it also has many shortcomings.

[0006] In summary, the desulfurization of coke oven gas faces the problems of dry desulfurization investment and high cost, which cannot meet the requirements of large-scale coke oven gas production. Traditional wet desulfurization has the problems of insufficient desulfurization depth and requires further deep treatment before it can be used, and the difficulty of treating waste liquid, which cannot guarantee the safe, stable, normal and optimal operation of subsequent equipment. If the desulfurized gas is used for other purposes, the organic sulfur needs to be converted into inorganic sulfur for removal, which requires large investment and high cost.

[0007] With the expansion of coking scale and industrial agglomeration, coke oven gas has become an important chemical raw material gas. The change in the use of coke oven gas has resulted in the original coke oven gas chemical product purification design indicators being far from meeting the current usage indicator requirements; abnormal chemical product desulfurization causes the desulfurizer of fine desulfurization to fail prematurely, affecting production operations, mainly due to sulfur penetration, forcing the early replacement of the desulfurizer. The resulting frequent replacement of the desulfurizer increases the cost of coke oven gas purification; in addition, the coke oven gas after chemical product purification contains tar and naphthalene, which seriously affects the normal operation of the compressor. The main reason is that the coke oven gas contains high tar and naphthalene content. During compression, the temperature rises and the tar gasifies and cokes, and the naphthalene condenses and crystallizes, causing naphthalene blockage in the compressor, making it impossible for the compressor to operate normally and forced to stop for repairs; sometimes the compressor has to be stopped for emergency repairs after only 1-2 days of operation, which makes production very passive, and often there is a situation of 1 on and 2 on standby or 1 on and 3 on standby.

[0008] The applicant intended to solve the above technical problem by absorbing methanol, but after a detailed search, no relevant technical solution was found.

[0009] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the Invention

[0010] The present application provides a coke oven gas purification device, comprising a water-washing ammonia tower, a feed pipeline being provided on one side of the water-washing ammonia tower, and the bottom of the water-washing ammonia tower being connected to an ammonia distillation tower;

[0011] The bottom of the ammonia still is provided with an ammonia still wastewater extraction pipeline, the top of the ammonia still is connected to the ammonia refining tower, one side of the ammonia refining tower is provided with an ammonia-containing material extraction pipeline, and the bottom of the ammonia refining tower is provided with an ammonia refining tower wastewater extraction pipeline;

[0012] The top of the water-washing ammonia tower is connected to the normal temperature methanol washing tower, the bottom of the normal temperature methanol washing tower is connected to the extraction tower, the top of the extraction tower is provided with an oil production pipeline, the bottom of the extraction tower is connected to the methanol water separator, the tower kettle of the methanol water separator is connected to the methanol water separator wastewater production pipeline, the top of the methanol water separator is connected to the middle and upper part of the methanol water separator through the methanol water separator tower top circulation pipeline, one end of the circulation pipeline is connected to the methanol water separator tower top circulation pipeline, and the other end of the circulation pipeline is connected to the normal temperature methanol washing tower;

[0013] The top of the normal temperature methanol washing tower is connected to the low temperature methanol washing tower through the normal temperature methanol washing tower top production pipeline. The top of the low temperature methanol washing tower is provided with a clean gas production pipeline. The bottom of the low temperature methanol washing tower is connected to the flash tower. The top of the flash tower is connected to the normal temperature methanol washing tower top production pipeline through the flash gas pipeline; the bottom of the flash tower is connected to the thermal regeneration tower, and the bottom of the thermal regeneration tower is connected to the middle and upper part of the low temperature methanol washing tower through the thermal regeneration tower kettle circulation pipeline.

[0014] As a preferred solution, the thermal regeneration tower kettle circulation pipeline is connected to the circulation pipeline one through a methanol replenishment pipeline.

[0015] As a preferred solution, the wastewater extraction pipeline of the ammonia refining tower is connected to the wastewater extraction pipeline of the ammonia distillation tower.

[0016] As a preferred solution, the wastewater extraction pipeline of the ammonia distillation tower is connected to the ammonia washing tower through a wastewater circulation pipeline, and a filter is provided on the wastewater circulation pipeline.

[0017] As a preferred solution, the top of the water-washing ammonia tower is connected to the normal-temperature methanol washing tower through a water-washing ammonia tower top pipeline, and a cooling device is provided on the water-washing ammonia tower top pipeline.

[0018] As a preferred solution, the cooling device includes a water cooling device and an ammonia cooling device connected in sequence.

[0019] As a preferred solution, a saturator is provided at the front of the cooling device.

[0020] As a preferred solution, the methanol-water separator wastewater utilization pipeline is connected to one end of the wastewater utilization pipeline, and the other end of the wastewater utilization pipeline is connected to the upper part of the extraction tower.

[0021] As a preferred solution, a compressor and a condensing device are provided on the extraction pipeline at the top of the normal temperature methanol washing tower.

[0022] As a preferred solution, the condensing device includes a water cooler, a condenser, and an ammonia cooler connected in sequence.

[0023] As a preferred solution, the clean gas production pipeline is connected to the input end and the output end of the condenser.

[0024] The present application provides a coke oven gas purification process, comprising the following steps:

[0025] S1: Coke oven gas enters the ammonia washing tower through the feed pipeline for ammonia washing;

[0026] S2: The washing water after washing ammonia at the bottom of the water washing ammonia tower enters the ammonia evaporation tower to evaporate ammonia;

[0027] S3: The ammonia produced at the top of the ammonia still tower enters the ammonia refining tower to separate the acid gas, which is then extracted from the top of the ammonia refining tower. Ammonia vapor is extracted from the side line in the middle of the ammonia refining tower and subjected to multiple cooling and separation to obtain 20% refined ammonia water or be processed into liquid ammonia.

[0028] S4: After the ammonia washing in the water washing tower, the coke oven gas is cooled and then enters the normal temperature methanol washing tower, where methanol is used to wash the coke oven gas to remove oil substances and some ammonia and sulfur in the coke oven gas;

[0029] S5: The washed methanol enters the extraction tower for extraction, and the oily substances are extracted from the top of the extraction tower. The methanol-water at the bottom of the extraction tower enters the methanol-water separator to remove water. The methanol is partially returned to the methanol-water separator for use as a circulating washing liquid, and partially returned to the normal temperature methanol washing tower for recycling. The water extracted from the bottom of the methanol-water separator is partially returned to the extraction tower for recycling, and the excess is sent to biochemical treatment.

[0030] S6: The coke oven gas washed with normal temperature methanol in the normal temperature methanol washing tower is pressurized by the compressor. The pressurized coke oven gas is cooled by the water cooler, condenser, and ammonia cooler, and then enters the low temperature methanol washing tower for washing to remove all other impurities in the coke oven gas and achieve the purification index;

[0031] S7: The methanol-rich solution after washing in the low-temperature methanol washing tower enters the flash tower for flash evaporation, and part of the carbon dioxide is flashed out. After being compressed by the compressor, it is mixed with the coke oven gas at the top of the normal temperature methanol washing tower and continues to enter the low-temperature methanol washing tower for washing; the flashed rich methanol enters the hot regeneration tower for regeneration, and the hot regeneration tower removes the acid gas, and the acid gas is extracted from the top of the hot regeneration tower; the regenerated methanol extracted from the kettle of the hot regeneration tower enters the low-temperature methanol washing tower for recycling.

[0032] As a preferred solution, the coke oven gas in S1 is first cooled in the cooling drum section to separate the tar and ammonia water, then pressurized by a blower and subjected to an electric tar replenisher to remove the tar entrainment before entering the water washing ammonia tower through the feed pipeline.

[0033] As a preferred solution, the ammonia content in the water washing ammonia tower in S1 is reduced to below 2 PPM after washing ammonia.

[0034] As a preferred solution, the remaining ammonia water in the cooling drum section of S2 and the washing water after washing ammonia at the bottom of the water-washing ammonia tower are fed into the ammonia evaporation tower to evaporate ammonia.

[0035] As a preferred solution, the acid gas produced in S3 is used to produce sulfur or sulfuric acid through Claus.

[0036] As a preferred solution, after the wastewater at the bottom of the ammonia distillation tower in S3 is filtered through a filter, a portion is circulated to the ammonia washing tower to wash ammonia, and the remaining portion is sent to biochemical treatment.

[0037] As a preferred solution, methanol at 0-5°C is used to wash the coke oven gas in the normal temperature methanol washing tower in S4.

[0038] As a preferred solution, the methanol in S5 is used as a circulating washing liquid and then partially returns to the methanol-water separator for use after heat exchange and cooling in the extraction tower kettle heat exchanger, and partially returns to the normal temperature methanol washing tower for recycling.

[0039] As a preferred solution, the compressor in S5 is pressurized to 2.5 MPa, and the waste liquid from the separation tanks of each stage of the compressor is returned to the extraction tower.

[0040] As a preferred solution, the pressurized coke oven gas in S6 is cooled to -25°C through a water cooler, a condenser and an ammonia cooler.

[0041] As a preferred solution, the rich methanol flashed out in S7 is subjected to heat exchange with the flash tower kettle heat exchanger and then enters the hot regeneration tower for regeneration.

[0042] As a preferred solution, the acid gas produced in S7 is used to produce sulfur or sulfuric acid through Claus.

[0043] This application has the following advantages:

[0044] 1. The purification device of this application has a short process, requires less equipment and investment, and the product coke oven gas has high purification index and can be directly used;

[0045] 2. No waste liquid, waste residue, or waste catalyst, green and environmentally friendly with low energy consumption;

[0046] 3. It can produce 20% ammonia water or liquid ammonia, with high product value;

[0047] 4. Acid gas can be used to produce sulfur or sulfuric acid through Claus, and the product value is high;

[0048] 5. The debenzene is quite thorough, the recovery rate is close to 100%, and the profit is high.

[0049] 6. This device can use the residual pressure of the gas from the coke oven to enter the expander to drive ammonia compression refrigeration, providing cooling capacity for this device and also providing part of the cooling capacity outside the boundary. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a schematic diagram of this application;

[0051] 1. Ammonia washing tower; 2. Feed pipeline; 3. Ammonia washing tower kettle pipeline; 4. Ammonia still; 5. Ammonia pipeline; 6. Ammonia still wastewater extraction pipeline; 7. Wastewater circulation pipeline; 8. Filter; 9. Ammonia still top pipeline; 10. Ammonia refining tower; 11. Ammonia-containing material extraction pipeline; 12. Ammonia refining tower wastewater extraction pipeline; 13. Ammonia washing tower top pipeline; 14. Normal temperature methanol washing tower; 15. Water cooling device; 16. Ammonia cooling device; 17. Saturator; 18. Normal temperature methanol washing tower kettle pipeline; 19. Extraction tower; 20. Oil extraction pipeline; 21. Extraction tower kettle pipeline; 22. Methanol-water separation tower; 23. Extraction tower kettle heat exchanger 1; 24. Extraction tower kettle heat exchanger 2; 25. Methanol-water separator wastewater extraction pipeline; 26. Wastewater utilization pipeline; 27. Wastewater cooler; 28. Methanol-water separator top circulation pipeline; 29. ​​Circulation pipeline; 30. Circulation pipeline water cooling device; 31. Circulation pipeline ammonia cooling device; 32. Reflux tank; 33. Reflux pump; 34. Normal temperature methanol wash tower top production pipeline; 35. Low temperature methanol wash tower; 36. Compressor; 37. Water cooler; 38. Condenser; 39. Ammonia cooler; 40. Clean coal gas production pipeline; 41. Low temperature methanol wash tower kettle pipeline; 42. Flash tower; 43. Condensate pipeline; 44. Condensate air cooler; 45. Flash gas pipeline; 46. Compressor 1; 47. Flash tower kettle pipeline; 48. Thermal regeneration tower; 49. Flash tower kettle heat exchanger; 50. Acid gas production pipeline; 51. Thermal regeneration tower kettle circulation pipeline; 52. Condensate ammonia cooler; 53. Methanol replenishment pipeline. DETAILED DESCRIPTION

[0052] The following is combined with Figure 1 The specific embodiments of the present invention are described in detail. It should be noted that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0053] Example 1:

[0054] This embodiment provides a coke oven gas purification device, comprising a water-washing ammonia tower 1, a feed pipeline 2 being provided on one side of the water-washing ammonia tower 1, the coke oven gas first being cooled in a cold drum section to separate tar and ammonia water, then being pressurized by a blower and an electric tar remover to remove tar entrainment, after which the coke oven gas enters the water-washing ammonia tower 1 through the feed pipeline 2 for ammonia washing to reduce the ammonia content to below 2 PPM; the bottom of the water-washing ammonia tower 1 is connected to the upper part of an ammonia still 4 through a water-washing ammonia tower kettle pipeline 3; the water-washing ammonia tower kettle pipeline 3 is connected to an ammonia water pipeline 5, and the residual ammonia water in the cold drum section enters the ammonia still 4 through the ammonia water pipeline 5 together with the washing water after ammonia washing at the bottom of the water-washing ammonia tower 1 to evaporate ammonia; the ammonia still 4 The bottom of the ammonia still is provided with an ammonia still wastewater extraction pipeline 6. Preferably, the ammonia still wastewater extraction pipeline 6 is connected to the ammonia washing tower 1 through a wastewater circulation pipeline 7. The wastewater circulation pipeline 7 is provided with a filter 8. The filtered wastewater enters the ammonia washing tower 1 to continue washing ammonia. The top of the ammonia still 4 is connected to the ammonia refining tower 10 through an ammonia still top pipeline 9. An ammonia-containing material extraction pipeline 11 is provided on one side of the ammonia refining tower 10. The ammonia-containing material extraction pipeline 11 extracts pure ammonia gas or 20% ammonia water. The bottom of the ammonia refining tower 10 is provided with an ammonia refining tower wastewater extraction pipeline 12. Preferably, the ammonia refining tower wastewater extraction pipeline 12 is connected to the ammonia still wastewater extraction pipeline 6.

[0055] The top of the water-washing ammonia tower 1 is connected to the normal temperature methanol washing tower 14 through the water-washing ammonia tower top pipeline 13. The water-washing ammonia tower top pipeline 13 is provided with a cooling device, and the cooling device includes a water cooling device 15 and an ammonia cooling device 16 connected in sequence; preferably, a saturator 17 is provided in front of the water cooling device 15 for fine washing and deammonification. When the water-washing ammonia tower 1 can meet the deammonification standard, there is no need to set the saturator 17, and the technicians can make corresponding settings according to the specific situation;

[0056] The bottom of the normal temperature methanol washing tower 14 is connected to the extraction tower 19 through the normal temperature methanol washing tower kettle pipeline 18. The top of the extraction tower 19 is provided with an oil extraction pipeline 20, which is used to extract oil substances and part of the ammonia and sulfur in the coke oven gas; the bottom of the extraction tower 19 is connected to the methanol-water separation tower 22 through the extraction tower kettle pipeline 21. The extraction tower kettle pipeline 21 is provided with an extraction tower kettle heat exchanger 1 23 and an extraction tower kettle heat exchanger 24. The kettle of the methanol-water separation tower 22 is connected to the methanol-water separation tower wastewater extraction pipeline 25. Preferably, the methanol-water separation tower wastewater extraction pipeline 25 passes through the extraction tower kettle heat exchanger 24 and exchanges heat with the extraction tower kettle heat exchanger 24. The wastewater after heat exchange is subjected to biochemical treatment. Further, the methanol-water separation tower wastewater extraction pipeline 25 is connected to one end of the wastewater utilization pipeline 26, and the other end of the wastewater utilization pipeline 26 is connected to the upper part of the extraction tower 19. A wastewater cooler 27 is provided on the wastewater utilization pipeline 26. Part of the wastewater extracted from the methanol-water separation tower 22 enters the extraction tower 19 for further extraction, and part is directly subjected to biochemical treatment.

[0057] The top of the methanol-water separation tower 22 is connected to the middle and upper part of the methanol-water separation tower 22 through the methanol-water separator top circulation pipeline 28, one end of the circulation pipeline 29 is connected to the methanol-water separation tower top circulation pipeline 28, and the other end of the circulation pipeline 29 is connected to the normal temperature methanol washing tower 14. The circulation pipeline 29 is provided with a circulation pipeline cooling device. Furthermore, the circulation pipeline cooling device includes a circulation pipeline water cooling device 30 and a circulation pipeline ammonia cooling device 31 connected in sequence, both of which are commonly used cooling devices in the prior art. Different description methods are used to distinguish different installation positions; preferably, the methanol-water separator top circulation pipeline 28 passes through the extraction tower kettle heat exchanger 23, and the methanol-water separator top circulation pipeline 28 is also provided with a reflux tank 32 and a reflux pump 33 respectively;

[0058] The top of the normal temperature methanol washing tower 14 is connected to the low temperature methanol washing tower 35 through the normal temperature methanol washing tower top extraction pipeline 34. The normal temperature methanol washing tower top extraction pipeline 34 is provided with a compressor 36 and a condensing device. The condensing device includes a water cooler 37, a condenser 38, and an ammonia cooler 39 connected in sequence; the top of the low temperature methanol washing tower 35 is provided with a clean gas extraction pipeline 40. Preferably, the clean gas extraction pipeline 40 passes through the condenser 38 for heat exchange, that is, the clean gas extraction pipeline 40 is connected to the input end and the output end of the condenser 38;

[0059] The bottom of the low-temperature methanol washing tower 35 is connected to the flash tower 42 through the low-temperature methanol washing tower bottom pipeline 41, and the low-temperature methanol washing tower bottom pipeline 41 is provided with a condensate air cooler 44; further, the water cooler 37, the condenser 38, and the ammonia cooler 39 are commonly connected to the condensate pipeline 43, and the condensate pipeline 43 is connected to the low-temperature methanol washing tower bottom pipeline 41; the top of the flash tower 42 is connected to the normal temperature methanol washing tower top extraction pipeline 34 through the flash gas pipeline 45, and the normal temperature methanol washing tower top extraction pipeline 34 is provided with a compressor 46, and the bottom of the flash tower 42 is connected to the hot regeneration tower 48 through the flash tower bottom pipeline 47, and the flash tower A flash tower kettle heat exchanger 49 is provided on the kettle pipeline 47. An acid gas extraction pipeline 50 is provided at the top of the thermal regeneration tower 48. The extracted acid gas is used to produce sulfur or sulfuric acid through Claus, and the product has high value. The bottom of the thermal regeneration tower 48 is connected to the middle and upper part of the low-temperature methanol washing tower 35 via a thermal regeneration tower kettle circulation pipeline 51. The thermal regeneration tower kettle circulation pipeline 51 passes through the flash tower kettle heat exchanger 49 and the condensate air cooler 44 in sequence. Furthermore, a condensate ammonia cooler 52 is provided on the rear side of the condensate air cooler 44. The thermal regeneration tower kettle circulation pipeline 51 is connected to the circulation pipeline 29 via a methanol replenishment pipeline 53 for replenishing methanol liquid.

[0060] The specific working principle of this application is:

[0061] The coke oven gas is first cooled in the cooling drum section to separate tar and ammonia water. After being pressurized by a blower and removed by an electric tar remover, the coke oven gas enters the water ammonia washing tower 1 through the feed pipeline 2 for ammonia washing to reduce the ammonia content to below 2PPM.

[0062] The washing water from the bottom of the ammonia washing tower 1 and the remaining ammonia water from the cooling drum section are fed into the ammonia still 4 for ammonia distillation. Approximately 10% ammonia water is produced at the top of the ammonia still 4 and then fed into the ammonia refining tower 10 to separate acid gas. The acid gas is extracted from the top of the ammonia still 4 and can be used to produce sulfur or sulfuric acid through Claus, which has high product value. Ammonia vapor is extracted from the side line in the middle of the ammonia refining tower 10 and subjected to multiple cooling and separation to obtain 20% refined ammonia water or further processed into liquid ammonia. The wastewater at the bottom of the ammonia still 4 passes through the filter 8, and part of it is recycled to the ammonia washing tower 1 for ammonia washing, while the excess is sent to biochemical treatment.

[0063] After ammonia washing in the water washing ammonia tower, the coke oven gas is cooled to about 5°C using a water cooling device 15 and an ammonia cooling device 16. The gas then enters a normal temperature methanol washing tower 14, where methanol at 0-5°C is used for washing to remove oil and some ammonia and sulfur from the coke oven gas. The washed methanol then enters an extraction tower 19 where it is extracted with water. The oil is removed from the top of the extraction tower 19 and sent to the tank farm for sale as crude benzene.

[0064] The methanol-water at the bottom of the extraction tower 19 enters the methanol-water separation tower 22 to remove water. The methanol is used as a circulating washing liquid and is heat-exchanged with the extraction tower kettle heat exchanger 23. After cooling, part of the methanol-water separation tower 22 is used, and part of it is returned to the normal temperature methanol washing tower 14 for recycling. Part of the water produced from the kettle of the methanol-water separation tower 22 is returned to the extraction tower 19 for recycling, and the excess is sent to biochemical treatment.

[0065] The coke oven gas washed with normal temperature methanol in the normal temperature methanol washing tower 14 is pressurized in the compressor 36 to 2.5 MPa. The waste liquid from the separators of the compressor 36 is returned to the extraction tower 19. The pressurized coke oven gas is cooled to about -25°C through the water cooler 37, condenser 38, and ammonia cooler 39. It then enters the low temperature methanol washing tower 35 for washing to remove all other impurities in the coke oven gas, achieving the purification indicators of 0.1 ppm total sulfur, 0.1 ppm ammonia, and no oil. The coke oven gas washed with low temperature methanol can be directly supplied to downstream users.

[0066] The methanol-rich solution after washing in the low-temperature methanol washing tower 35 enters the flash tower 42 for flash evaporation, flashing out part of the carbon dioxide, which is compressed by the compressor 46 and mixed with the coke oven gas at the top of the normal-temperature methanol washing tower 14 before continuing to enter the low-temperature methanol washing tower 35 for washing; the flashed rich methanol exchanges heat with the flash tower kettle heat exchanger 49 and then enters the hot regeneration tower 48 for regeneration. The hot regeneration tower 48 removes the acid gas, which is extracted from the top of the hot regeneration tower 48 and can subsequently be used to produce sulfur or sulfuric acid through Claus, with high product value; the regenerated methanol extracted from the kettle of the hot regeneration tower 48 enters the low-temperature methanol washing tower 35 for recycling after heat exchange.

[0067] Example 2:

[0068] This embodiment provides a coke oven gas purification process, comprising the following steps:

[0069] S1: The coke oven gas enters the water-washing ammonia tower 1 through the feed pipeline 2 for ammonia washing to reduce the ammonia content to below 2 PPM. Preferably, before entering the water-washing ammonia tower 1, the coke oven gas is first cooled in a cooling drum section to separate tar and ammonia water, then pressurized by a blower and subjected to an electric tar remover to remove tar entrainment before entering the water-washing ammonia tower 1 through the feed pipeline.

[0070] S2: The washing water after washing ammonia at the bottom of the water-washing ammonia tower 1 enters the ammonia still 4 to evaporate ammonia; preferably, the remaining ammonia water in the cold drum section and the washing water after washing ammonia at the bottom of the water-washing ammonia tower 1 enter the ammonia still 4 together to evaporate ammonia;

[0071] S3: Ammonia produced at the top of ammonia still 4 enters ammonia refining tower 10 to separate acid gas. The acid gas is extracted from the top of ammonia refining tower 10 and can be used to produce sulfur or sulfuric acid through Claus. Ammonia vapor is extracted from the side line in the middle of ammonia refining tower 10 and subjected to multiple cooling and separation to obtain 20% refined ammonia water or be processed into liquid ammonia. The wastewater at the bottom of ammonia still 4 is filtered through filter 8, a portion of which is recycled to ammonia washing tower 1 for ammonia washing, and the remaining portion is sent to biochemical treatment.

[0072] S4: After the ammonia washing in the water washing ammonia tower 1, the coke oven gas is cooled and then enters the normal temperature methanol washing tower 14, where methanol at 0°C-5°C is used to wash the coke oven gas to remove oil substances and part of the ammonia and sulfur in the coke oven gas;

[0073] S5: The washed methanol enters the extraction tower 19 for extraction, and the oily substances are extracted from the top of the extraction tower 19; the methanol water at the bottom of the extraction tower 19 enters the methanol-water separation tower 22 to remove water, and the methanol is used as a circulating washing liquid. After heat exchange with the extraction tower kettle heat exchanger 23 and cooling, part of it returns to the methanol-water separation tower 22 for use, and part of it returns to the normal temperature methanol washing tower 14 for recycling; part of the water extracted from the kettle of the methanol-water separation tower 22 is returned to the extraction tower for recycling, and the excess part is sent to biochemical treatment;

[0074] S6: The coke oven gas washed with normal temperature methanol in the normal temperature methanol washing tower 14 is pressurized in the compressor 36, which pressurizes the gas to 2.5 MPa. The waste liquid from the separators of the compressor 36 is returned to the extraction tower 19. The pressurized coke oven gas is cooled to about -25°C through the water cooler 37, condenser 38, and ammonia cooler 39 and then enters the low temperature methanol washing tower 35 for washing to remove all other impurities in the coke oven gas and achieve the purification index.

[0075] S7: The methanol-rich solution after washing in the low-temperature methanol washing tower 35 enters the flash tower 42 for flash evaporation, flashing out part of the carbon dioxide, which is compressed by the compressor 46 and mixed with the coke oven gas at the top of the normal-temperature methanol washing tower 14, and then continues to enter the low-temperature methanol washing tower 35 for washing; the flashed rich methanol exchanges heat with the flash tower kettle heat exchanger 49 and then enters the hot regeneration tower 48 for regeneration. The hot regeneration tower 48 removes the acid gas, and the acid gas is extracted from the top of the hot regeneration tower 48. The extracted acid gas can be used to produce sulfur or sulfuric acid through Claus; the regenerated methanol extracted from the kettle of the hot regeneration tower 48 enters the low-temperature methanol washing tower 35 for recycling.

[0076] In summary, due to the adoption of the above-mentioned technical solution, the present application has a shorter purification process, less equipment investment, less floor space, and a high coke oven gas purification index compared to the purification device in the prior art, and can be directly used; in addition, it has the advantages of no waste liquid, waste residue, or waste catalyst, being green and environmentally friendly; low energy consumption; relatively thorough debenzenization, a recovery rate of nearly 100%, and high profits.

[0077] The preferred embodiment of the present application is described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the specific details in the above-mentioned embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, the various possible combinations of this application will not be described separately.

[0079] In addition, the various implementation methods of the present application can be arbitrarily combined, as long as they do not violate the concept of the present application, and they should also be regarded as the contents disclosed in the present application.

Claims

1. A coke oven gas purification device, comprising a water washing ammonia tower (1), a feed pipeline (2) being provided on one side of the water washing ammonia tower (1), characterized in that: The bottom of the ammonia washing tower (1) is connected to the ammonia distillation tower (4); The bottom of the ammonia evaporation tower (4) is provided with an ammonia evaporation tower wastewater extraction pipeline (6), the top of the ammonia evaporation tower (4) is connected to the ammonia refining tower (10), one side of the ammonia refining tower (10) is provided with an ammonia-containing material extraction pipeline (11), and the bottom of the ammonia refining tower (10) is provided with an ammonia refining tower wastewater extraction pipeline (12); The top of the water-washing ammonia tower (1) is connected to the normal temperature methanol washing tower (14), the bottom of the normal temperature methanol washing tower (14) is connected to the extraction tower (19), the top of the extraction tower (19) is provided with an oil extraction pipeline (20), the bottom of the extraction tower (19) is connected to the methanol water separation tower (22), the tower bottom of the methanol water separation tower (22) is connected to the methanol water separator wastewater extraction pipeline (25), the top of the methanol water separation tower (22) is connected to the middle and upper part of the methanol water separation tower (22) through the methanol water separation tower top circulation pipeline (28), one end of the circulation pipeline (29) is connected to the methanol water separation tower top circulation pipeline (28), and the other end of the circulation pipeline (29) is connected to the normal temperature methanol washing tower (14); The top of the normal temperature methanol washing tower (14) is connected to the low temperature methanol washing tower (35) through the normal temperature methanol washing tower top extraction pipeline (34), the top of the low temperature methanol washing tower (35) is provided with a clean coal gas extraction pipeline (40), the bottom of the low temperature methanol washing tower (35) is connected to the flash tower (42), the top of the flash tower (42) is connected to the normal temperature methanol washing tower top extraction pipeline (34) through the flash gas pipeline (45); the bottom of the flash tower (42) is connected to the thermal regeneration tower (48), and the bottom of the thermal regeneration tower (48) is connected to the middle and upper part of the low temperature methanol washing tower (35) through the thermal regeneration tower bottom circulation pipeline (51).

2. A coke oven gas purification device according to claim 1, characterized in that: The thermal regeneration tower kettle circulation pipeline (51) is connected to the circulation pipeline (29) through the methanol supplement pipeline (53).

3. The coke oven gas purification device according to claim 1, characterized in that: The ammonia evaporation tower wastewater extraction pipeline (6) is connected to the ammonia washing tower (1) through a wastewater circulation pipeline (7), and a filter (8) is provided on the wastewater circulation pipeline (7).

4. The coke oven gas purification device according to claim 1, characterized in that: The ammonia refining tower wastewater extraction pipeline (12) is connected to the ammonia distillation tower wastewater extraction pipeline (6).

5. The coke oven gas purification device according to claim 1, characterized in that: The top of the water-washing ammonia tower (1) is connected to a normal-temperature methanol washing tower (14) via a water-washing ammonia tower top pipeline (13), and a cooling device is provided on the water-washing ammonia tower top pipeline (13).

6. The coke oven gas purification device according to claim 5, characterized in that: A saturator (17) is provided at the front of the cooling device.

7. The coke oven gas purification device according to claim 1, characterized in that: The methanol-water separator wastewater extraction pipeline (25) is connected to one end of the wastewater utilization pipeline (26), and the other end of the wastewater utilization pipeline (26) is connected to the upper part of the extraction tower (19).

8. A coke oven gas purification process, characterized in that: The steps include: S1: Coke oven gas enters the ammonia washing tower (1) through the feed pipeline (2) for ammonia washing; S2: The washing water after washing ammonia at the bottom of the water washing ammonia tower (1) enters the ammonia evaporation tower (4) to evaporate ammonia; S3: The ammonia water produced at the top of the ammonia distillation tower (4) enters the ammonia water refining tower (10) to separate the acid gas, and the acid gas is extracted from the top of the ammonia water refining tower (10); the ammonia vapor is extracted from the side line in the middle of the ammonia water refining tower (10) and subjected to multiple cooling and separation to obtain 20% refined ammonia water or processed into liquid ammonia; S4: The coke oven gas after ammonia washing in the water washing ammonia tower (1) is cooled and then enters the normal temperature methanol washing tower (14), where methanol is used to wash the coke oven gas to remove oil substances and part of the ammonia and sulfur in the coke oven gas; S5: The washed methanol enters the extraction tower (19) for extraction, and the oily substances are extracted from the top of the extraction tower (19); the methanol water at the bottom of the extraction tower (19) enters the methanol water separation tower (22) to remove water, and the methanol is partially returned to the methanol water separation tower (22) for use as a circulating washing liquid, and partially returned to the normal temperature methanol washing tower (14) for recycling; the water extracted from the bottom of the methanol water separation tower (22) is partially returned to the extraction tower (19) for recycling, and the excess is sent to biochemical treatment; S6: The coke oven gas washed with normal temperature methanol in the normal temperature methanol washing tower (14) is pressurized in the compressor (36). The pressurized coke oven gas is cooled by the water cooler (37), condenser (38), and ammonia cooler (39) and then enters the low temperature methanol washing tower (35) for washing to remove all other impurities in the coke oven gas and achieve the purification index; S7: The methanol-rich solution after washing in the low-temperature methanol washing tower (35) enters the flash tower (42) for flash evaporation, flashing out part of the carbon dioxide, which is then compressed by the compressor 1 (46) and mixed with the coke oven gas at the top of the normal-temperature methanol washing tower (14), and then continues to enter the low-temperature methanol washing tower (35) for washing; the flashed rich methanol enters the hot regeneration tower (48) for regeneration, and the hot regeneration tower (48) removes the acid gas, which is extracted from the top of the hot regeneration tower (48); The regenerated methanol extracted from the bottom of the thermal regeneration tower (48) enters the low-temperature methanol washing tower (35) for recycling.

9. A coke oven gas purification process according to claim 8, characterized in that: After the wastewater at the bottom of the ammonia evaporation tower (4) in S3 is filtered through the filter (8), a portion of it is circulated to the ammonia washing tower (1) for ammonia washing, and the remaining portion is sent to biochemical treatment.

10. A coke oven gas purification process according to claim 8, characterized in that: The rich methanol flashed out in S7 exchanges heat with the flash tower kettle heat exchanger and then enters the hot regeneration tower for regeneration.

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