Method for efficient desulfurization and mist capture of coke oven gas in wet desulfurization process

Abstract

This invention discloses a method for efficient desulfurization and mist elimination of coke oven gas in a wet desulfurization process, relating to the field of gas desulfurization technology. The method includes the following steps: S1: After being cooled by a pre-cooling tower, the gas is transported through a pipeline to a primary desulfurization absorption tower. Two sets of primary desulfurization absorption towers are used. The desulfurization liquid in the primary desulfurization absorption towers desulfurizes the incoming gas. S2: The desulfurized gas is transported from the top of the primary desulfurization absorption tower to a secondary desulfurization absorption tower through a pipeline. By adding a micro-absorber and a scrubbing mist eliminator after the secondary desulfurization absorption tower, the entrainment of gas mist can be reduced under normal circumstances, lowering the hydrogen sulfide content in the gas. Furthermore, by using pipeline valves to allow the gas to pass through the micro-absorber and scrubbing mist eliminator, the desulfurization effect is further enhanced, minimizing the amount of ammonium polysulfide in the gas, increasing the gas temperature, and ensuring the water balance in the ammonium sulfate section. This significantly reduces the frequency of clogging of the mist eliminator after the desulfurization tower.

Description

Technical Field

[0001] This invention relates to the field of coal gas desulfurization technology, specifically to a method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process. Background Technology

[0002] In the coke oven gas purification process, after desulfurization in a wet desulfurization tower, coke oven gas produces entrainment mist. The entrained desulfurization liquid contains substances such as ammonium polysulfides. Ammonium polysulfides, as an intermediate product in the desulfurization process, react with sulfuric acid in the ammonium sulfate mother liquor in the saturator of the next gas purification step—the ammonium sulfate step—to generate hydrogen sulfide, which is released into the gas. This leads to an abnormally high hydrogen sulfide content in the gas after the saturator. Actual data on hydrogen sulfide content in the gas before and after the ammonium sulfate step in coking plants with similar processes confirms this phenomenon. These factors ultimately result in SO2 emissions exceeding standards for users emitting coke oven gas as industrial or residential fuel. The relevant chemical equations are as follows:

[0003] H₂S + NH₃·H₂O = NH₄HS + H₂O;

[0004]

[0005] (NH4)2S x +1 / 2O2+H2OS x +2NH3·H2O

[0006] Due to the aforementioned problem of mist entrainment, the common industrial practice is to use a ring-shaped mist eliminator at the top of the desulfurization tower and a swirl plate mist eliminator on the gas pipeline after the desulfurization tower. However, the desulfurization liquid entrained in the gas still causes high resistance in the pipeline swirl plate mist eliminator and makes it difficult to clean online, resulting in increased pressure after the gas blower, increasing energy consumption and equipment operation safety risks.

[0007] The existing patent CN215365621U discloses a pipeline-type mist eliminator after a coking desulfurization tower, belonging to the field of coking gas mist elimination and purification technology. This pipeline-type mist eliminator includes a shell, a liquid collection hopper, a gas outlet, a gas inlet pipe, a fixing component, a drain pipe, and a manhole. The gas inlet pipe is welded to the shell by a fixing component. The drain pipe is inserted into the coking desulfurization tower through the shell, and the liquid collection hopper is connected to the drain pipe. A gas outlet is opened on the upper side of the shell, and a manhole is opened on the lower side of the shell. This patent only uses mechanical sedimentation to eliminate mist, which has poor effect.

[0008] CN205200046U discloses a cleaning device for a mist eliminator in a gas purification system, relating to the field of cleaning technology for various modules of a gas purification system. Specifically, it provides a cleaning device for a mist eliminator in a gas purification system, including a cleaning tank, a blowing device, a washing liquid storage tank, and a heating device. The blowing device is composed of a high-pressure air pump and a bubbling pipe connected sequentially via a blowing pipe. The bubbling pipe is laid at the bottom of the cleaning tank and has multiple bubbling holes. The washing liquid storage tank is connected to the cleaning tank via a washing liquid delivery pipe, and a washing liquid delivery pump is connected to the washing liquid delivery pipe. The heating device is connected to the blowing pipe between the high-pressure air pump and the bubbling pipe to heat the gas. However, this mist eliminator cannot be cleaned online, affecting continuous production.

[0009] CN204352660U discloses a high-efficiency ammonia desulfurization demister, including a demister module, blades, and flushing water pipes. The demister module consists of blades formed into blade plates, which are arranged in a ridge-like structure. Each blade plate is fixed by a positioning plate at the upper and lower parts of the horizontally arranged blades. The space between the blades is a channel for the demisting airflow. The cross-sectional shape of the blades is wavy or V-shaped. This type of demister is suitable for wet flue gas desulfurization processes, which are mainly used to remove SO2 from flue gas. It is not suitable for wet desulfurization processes in coke oven gas purification. Summary of the Invention

[0010] To overcome the aforementioned technical problems, the present invention aims to provide a highly efficient desulfurization and mist-catching method for coke oven gas in a wet desulfurization process. By adding a micro absorber and a scrubbing mist-catching tower after the secondary desulfurization absorption tower, the entrainment of gas mist can be reduced under normal circumstances, thus lowering the hydrogen sulfide content in the gas. Furthermore, through the design of pipeline valves, the gas can pass through the micro absorber and scrubbing mist-catching tower, further enhancing the desulfurization effect, minimizing the amount of ammonium polysulfide in the gas, increasing the gas temperature, ensuring the water balance in the ammonium sulfate section, and significantly reducing the frequency of clogging of the mist catching tower after the desulfurization tower.

[0011] The objective of this invention can be achieved through the following technical solutions:

[0012] A highly efficient desulfurization and mist-eliminating method for coke oven gas in a wet desulfurization process includes the following steps:

[0013] S1: After being cooled by the pre-cooling tower, the coal gas is transported to the primary desulfurization absorption tower through pipeline. There are two sets of primary desulfurization absorption towers. The desulfurization liquid in the primary desulfurization absorption tower desulfurizes the incoming coal gas.

[0014] S2: The desulfurized coal gas is transported from the top of the primary desulfurization absorption tower to the secondary desulfurization absorption tower through a pipeline;

[0015] S3: The secondary desulfurization absorption tower performs secondary desulfurization treatment on the coal gas using desulfurization liquid, and then the coal gas after secondary desulfurization is transported to the micro absorber through pipeline.

[0016] S4: The micro absorber performs three desulfurization treatments on the coal gas. The output end of the micro absorber is connected to the bottom of the scrubbing and mist-catching tower through a pipeline. The micro absorber transports the coal gas to the scrubbing and mist-catching tower through the pipeline.

[0017] S5: The internal structure of the washing mist tower is a three-layer mist-catching structure. The bottom layer first intercepts and collects the desulfurization liquid delivered by the micro absorber through the packing of the first-stage mist-catching section to the bottom storage tank of the tower. Then, the desulfurization liquid circulation pump at the bottom of the tower is used to circulate it to the top of the packing of the first-stage mist-catching section for spraying and washing.

[0018] S6: The coal gas passing through the primary mist-catching section packing will enter the intermediate layer of the washing mist-catching tower. The secondary mist-catching section packing is washed and sprayed with ammonia water. The secondary mist-catching section packing intercepts and collects the gas into the intermediate layer storage tank, and then uses the bottom desulfurization liquid circulation pump to circulate it to the top of the secondary mist-catching packing section for spraying and washing.

[0019] S7: The packing material in the upper three-stage mist-catching section of the washing mist-catching tower is washed with steam condensate, and the gas after mist catching is transported out through the pipeline at the top of the washing mist-catching tower.

[0020] As a further aspect of the present invention: the number of primary desulfurization absorption towers is two sets, and the bottom of the two sets of primary desulfurization absorption towers are connected to regeneration towers through pipelines. The regeneration towers are used to recover and regenerate the desulfurization liquid transported from the primary desulfurization absorption towers, and after regeneration, it is transported back to the primary desulfurization absorption towers for continued desulfurization treatment.

[0021] As a further aspect of the present invention: the tower body of the secondary desulfurization absorption tower is divided into a desulfurization section and a regeneration section. The two streams of coal gas washed by the desulfurization liquid in the two primary desulfurization towers are gathered together, and then two pipelines are set up to transport them to the desulfurization section and the micro absorber of the secondary desulfurization absorption tower respectively.

[0022] As a further aspect of the present invention: the temperature of the steam condensate used in the packing of the upper three-stage mist-catching section of the washing mist-catching tower is 50℃-70℃.

[0023] As a further aspect of the present invention: the primary mist-catching section packing, the secondary mist-catching section packing, and the tertiary mist-catching section packing have the same structure, all including a packing body. The packing body has several internal through grooves evenly distributed inside. An arc-shaped through groove is provided in the middle of the internal through groove, and a backflow buckle is provided on the side wall of the arc-shaped through groove.

[0024] As a further aspect of the present invention: the outlet pipeline of the circulating pump installed on the side of the washing and mist-catching tower is provided with a branch, which is connected to the primary desulfurization absorption tower or the secondary desulfurization absorption tower, for transporting the desulfurization liquid in the washing and mist-catching tower to the primary desulfurization absorption tower or the secondary desulfurization absorption tower for recycling.

[0025] As a further aspect of the present invention: the desulfurization liquid in the primary desulfurization absorption tower and the secondary desulfurization absorption tower is made of complexed iron or DDS desulfurization catalyst or a mixture of the two in any proportion.

[0026] As a further aspect of the present invention: the ammonia water used in the intermediate layer of the washing and mist-catching tower is ammonia water from the salt extraction section, concentrated ammonia water from the ammonia stripping section, concentrated ammonia water from the phosphoric acid washing section, or any mixture of the above ammonia waters in any proportion.

[0027] As a further aspect of the present invention: the desulfurization liquid used for spraying desulfurization in the micro absorber comes from the regeneration tower matched with the primary desulfurization absorption tower or the regeneration section at the top of the secondary desulfurization absorption tower, and preferably the desulfurization liquid regenerated by the regeneration tower matched with the primary desulfurization absorption tower.

[0028] The beneficial effects of this invention are:

[0029] 1. In this invention, by adding a micro absorber, on the one hand, the entrainment of gas mist can be reduced under normal circumstances, thus reducing the hydrogen sulfide content of the gas; on the other hand, through the design of pipeline valves, the gas can also pass through the micro absorber and the scrubbing mist tower.

[0030] 2. In this invention, after the micro absorber is installed in the secondary desulfurization absorption tower, the desulfurization liquid generated by the micro absorber is collected in the washing and mist-catching tower and then circulated and sprayed again on the packing material in the lower layer of the washing and mist-catching tower, which further enhances the desulfurization effect.

[0031] 3. In this invention, the washing mist tower is set as a three-stage mist-catching structure. At the same time, in combination with the actual process requirements, ammonia water is added in the second stage mist-catching section. On the one hand, it further absorbs the gas mist droplets and washes away the impurities in the absorption process. On the other hand, it maintains the stability of the system pH. The introduction of steam condensate at 50℃-70℃ in the third stage is to reduce the amount of ammonium polysulfide in the gas as much as possible, increase the gas temperature, and ensure the water balance of the ammonium sulfate section.

[0032] 4. In this invention, the washing method is used to capture mist, which avoids the problems of the commonly used static packing mist capture method. That is, if mist is captured but not washed, impurities in the gas will remain in the packing. Over time, the packing will be easily blocked, which will require production shutdown for maintenance and affect the continuity of production.

[0033] 5. In this invention, the desulfurization liquid uses complexed iron or DDS desulfurization catalyst. The sulfur foam generated in the desulfurization system of complexed iron or DDS desulfurization catalyst is viscous and the sulfur particles are small, which are easily carried out by the gas. The set-in scrubbing mist eliminator can greatly reduce the number of times the mist eliminator after the desulfurization tower is blocked. At the same time, the set-in scrubbing mist eliminator can significantly reduce the gas resistance of the desulfurization system because of its low resistance and continuous stability. This can reduce the pressure loss of the gas blower and save energy. As for PDS desulfurization catalyst, the desulfurization efficiency can be increased by adding micro absorbers, which also has a very high application prospect.

[0034] 6. The use of two sets of primary desulfurization absorption towers is a measure adopted for desulfurization systems that handle large amounts of coal gas, such as coke oven gas with a capacity of 100,000 m3 / h or more. If the coal gas volume is small, one set of primary desulfurization absorption towers can be adopted, and a secondary desulfurization + micro absorber + scrubbing mist eliminator or a tertiary desulfurization + micro absorber + scrubbing mist eliminator type can be used. The pipeline layout is simpler than that described in this invention. Attached Figure Description

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] Figure 1 This is a process flow diagram of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the mist-catching section packing in this invention.

[0038] In the diagram: 1. Packing body; 2. Internal through groove; 3. Arc-shaped through groove; 4. Backflow buckle. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1:

[0041] like Figure 1 and Figure 2 As shown, a highly efficient desulfurization and mist-eliminating method for coke oven gas in a wet desulfurization process includes the following steps:

[0042] S1: After being cooled by the precooling tower, the coal gas is transported through pipeline to the bottom of the primary desulfurization absorption tower. There are two sets of primary desulfurization absorption towers. The desulfurization liquid in the primary desulfurization absorption tower desulfurizes the incoming coal gas.

[0043] S2: The desulfurized coal gas is transported from the top of the primary desulfurization absorption tower to the secondary desulfurization absorption tower through a pipeline, while the desulfurization liquid at the bottom of the primary desulfurization absorption tower is transported from the bottom to the regeneration tower through a pipeline. The generated sulfur foam overflows from the top to the sulfur foam tank for treatment, and the regenerated desulfurization liquid is then transported back to the primary desulfurization absorption tower for further desulfurization treatment.

[0044] S3: The secondary desulfurization absorption tower is divided into a desulfurization section and a regeneration section. The two streams of coal gas washed by the desulfurization liquid in the two primary desulfurization towers are gathered together, and then two pipelines are set up to transport them to the desulfurization section and the micro absorber of the secondary desulfurization absorption tower, respectively. The coal gas undergoes secondary desulfurization treatment in the desulfurization section. The amount of coal gas in the two towers is balanced by setting valves. After secondary desulfurization in the desulfurization section, the coal gas is transported to the micro absorber through pipelines. The desulfurization liquid in the primary and secondary desulfurization absorption towers is made of complexed iron.

[0045] S4: The micro absorber performs three desulfurization treatments on the coal gas. The desulfurization liquid used for spraying desulfurization in the micro absorber comes from the regeneration tower matched with the primary desulfurization absorption tower or the regeneration section at the top of the secondary desulfurization absorption tower. The desulfurization liquid regenerated by the regeneration tower matched with the primary desulfurization absorption tower is preferred. The output end of the micro absorber is connected to the bottom end of the scrubbing and mist-catching tower through a pipeline. The micro absorber transports the coal gas to the scrubbing and mist-catching tower through the pipeline.

[0046] S5: The washing mist-catching tower is set up with a three-stage mist-catching structure. The bottom layer intercepts and collects the desulfurization liquid delivered by the micro absorber through the packing of the first-stage mist-catching section to the bottom storage tank of the tower. Then, the desulfurization liquid circulation pump at the bottom of the tower is used to circulate it to the top of the packing of the first-stage mist-catching section for spraying and washing. After the desulfurization liquid level at the bottom of the tower rises, it is sent to the second-stage desulfurization absorption tower for mixing and regeneration through the branch of the circulation pump outlet pipeline.

[0047] During the maintenance of the secondary desulfurization tower, the inlet valve of the secondary desulfurization tower can be closed, and the gas can be bypassed and directly enter the micro absorber before entering the scrubbing mist tower. This is because the micro absorber also has a desulfurization efficiency of 30%-50%, thus reducing the problems of increased hydrogen sulfide content in the coal gas and mist entrainment caused by system maintenance.

[0048] S6: The packing material in the intermediate layer of the mist-catching tower is washed and sprayed with ammonia water. The ammonia water itself can also absorb residual hydrogen sulfide in the coal gas. The packing material in the intermediate layer intercepts and collects the hydrogen sulfide in the coal gas and then uses the desulfurization liquid circulation pump at the bottom of the tower to circulate it to the top of the secondary mist-catching packing material for spraying and washing. After the desulfurization liquid level in the intermediate layer storage tank rises, it is sent to the secondary desulfurization absorption tower for mixing and regeneration through a branch of the circulation pump outlet pipeline. The ammonia water itself can also absorb residual hydrogen sulfide in the coal gas. This design can reduce the phenomenon of coal gas entrainment.

[0049] S7: The packing material in the upper three-stage mist-catching section of the washing mist-catching tower is washed with 60℃ steam condensate. On the one hand, this can increase the temperature of the coal gas, which helps to reduce the amount of steam used for heating in the ammonium sulfate section; on the other hand, the ammonium sulfate section is a water-deficient process, which is prone to water shortage and water balance disruption, causing the liquid level in the full-flow tank of the ammonium sulfate section to drop and creating a risk of coal gas leakage. The coal gas will carry away some of the clean steam condensate, which can alleviate this situation. At the same time, the steam condensate has extremely low impurities, which can fully dissolve and absorb the polysulfide ammonium salts contained in the coal gas and enter the ammonia absorption section below before finally being added to the primary and secondary desulfurization systems. The coal gas after mist catching is transported out through the pipeline at the top of the washing mist-catching tower.

[0050] The primary mist-catching section packing, the secondary mist-catching section packing, and the tertiary mist-catching section packing have the same structure, all including a packing body 1. Several internal through grooves 2 are evenly opened inside the packing body 1. An arc-shaped through groove 3 is provided in the middle of the internal through groove 2. A backflow buckle 4 is provided on the side wall of the arc-shaped through groove 3.

[0051] Example 2:

[0052] like Figure 1 and Figure 2 As shown, a highly efficient desulfurization and mist-eliminating method for coke oven gas in a wet desulfurization process includes the following steps:

[0053] S1: After being cooled by the precooling tower, the coal gas is transported through pipeline to the bottom of the primary desulfurization absorption tower. There are two sets of primary desulfurization absorption towers. The desulfurization liquid in the primary desulfurization absorption tower desulfurizes the incoming coal gas.

[0054] S2: The desulfurized coal gas is transported from the top of the primary desulfurization absorption tower to the secondary desulfurization absorption tower through a pipeline, while the desulfurization liquid at the bottom of the primary desulfurization absorption tower is transported from the bottom to the regeneration tower through a pipeline. The generated sulfur foam overflows from the top to the sulfur foam tank for treatment, and the regenerated desulfurization liquid is then transported back to the primary desulfurization absorption tower for further desulfurization treatment.

[0055] S3: The secondary desulfurization absorption tower is divided into a desulfurization section and a regeneration section. The two streams of coal gas washed by the desulfurization liquid in the two primary desulfurization towers are gathered together, and then two pipelines are set up to transport them to the desulfurization section and the micro absorber of the secondary desulfurization absorption tower, respectively. The coal gas undergoes secondary desulfurization treatment in the desulfurization section. The amount of coal gas in the two towers is balanced by setting valves. After secondary desulfurization in the desulfurization section, the coal gas is transported to the micro absorber through pipelines. The desulfurization liquid in the primary and secondary desulfurization absorption towers is made of DDS desulfurization catalyst.

[0056] S4: The micro absorber performs three desulfurization treatments on the coal gas. The desulfurization liquid used for spraying desulfurization in the micro absorber comes from the regeneration tower matched with the primary desulfurization absorption tower or the regeneration section at the top of the secondary desulfurization absorption tower. The desulfurization liquid regenerated by the regeneration tower matched with the primary desulfurization absorption tower is preferred. The output end of the micro absorber is connected to the bottom end of the scrubbing and mist-catching tower through a pipeline. The micro absorber transports the coal gas to the scrubbing and mist-catching tower through the pipeline.

[0057] S5: The washing mist-catching tower is set up with a three-stage mist-catching structure. The bottom layer intercepts and collects the desulfurization liquid delivered by the micro absorber through the packing of the first-stage mist-catching section to the bottom storage tank of the tower. Then, the desulfurization liquid circulation pump at the bottom of the tower is used to circulate it to the top of the packing of the first-stage mist-catching section for spraying and washing. After the desulfurization liquid level at the bottom of the tower rises, it is sent to the first-stage desulfurization absorption tower for mixing and regeneration through the branch of the circulation pump outlet pipeline.

[0058] When one of the primary desulfurization towers is under maintenance, a portion of the coal gas can be passed through the bypass pipe of this desulfurization tower, while about half of the coal gas enters the primary desulfurization tower that is not under maintenance. After the gas is combined, it enters the secondary desulfurization tower, the micro absorber and the scrubbing mist tower in sequence. This can also ensure that the hydrogen sulfide content in the coal gas meets the standards and that the entrained mist is captured.

[0059] S6: The packing material in the intermediate layer of the mist-catching tower is washed and sprayed with ammonia water. The ammonia water itself can also absorb the residual hydrogen sulfide in the coal gas. The packing material in the intermediate layer intercepts and collects the hydrogen sulfide in the intermediate layer storage tank. Then, the desulfurization liquid circulation pump at the bottom of the tower is used to circulate the liquid to the top of the secondary mist-catching packing section for spraying and washing. After the desulfurization liquid level in the intermediate layer storage tank rises, it is sent to the primary desulfurization absorption tower for mixing and regeneration through a branch of the circulation pump outlet pipeline.

[0060] S7: The packing material in the upper three-stage mist-catching section of the washing mist-catching tower is washed with 70℃ steam condensate. On the one hand, this can increase the temperature of the coal gas, which helps to reduce the amount of steam used for heating in the ammonium sulfate section; on the other hand, the ammonium sulfate section is a water-deficient process, which is prone to water shortage and water balance disruption, causing the liquid level in the full-flow tank of the ammonium sulfate section to drop and creating a risk of coal gas leakage. The coal gas will carry away some of the clean steam condensate, which can alleviate this situation. At the same time, the steam condensate has extremely low impurities, which can fully dissolve and absorb the polysulfide ammonium salts contained in the coal gas and enter the ammonia absorption section below before finally being added to the primary and secondary desulfurization systems. The coal gas after mist catching is transported out through the pipeline at the top of the washing mist-catching tower.

[0061] The primary mist-catching section packing, the secondary mist-catching section packing, and the tertiary mist-catching section packing have the same structure, all including a packing body 1. Several internal through grooves 2 are evenly opened inside the packing body 1. An arc-shaped through groove 3 is provided in the middle of the internal through groove 2. A backflow buckle 4 is provided on the side wall of the arc-shaped through groove 3.

[0062] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process, characterized in that, It includes the following steps: S1: After being cooled in the pre-cooling tower, the coal gas is transported through a pipeline to the primary desulfurization absorption tower. The number of primary desulfurization absorption towers is two groups. The desulfurization liquid in the primary desulfurization absorption tower desulfurizes the incoming coal gas. S2: The desulfurized coal gas is transported from the top of the primary desulfurization absorption tower through a pipeline to the secondary desulfurization absorption tower. S3: The secondary desulfurization absorption tower conducts secondary desulfurization treatment on the coal gas with desulfurization liquid, and then transports the coal gas after secondary desulfurization through a pipeline to the micro-absorber. S4: The micro-absorber conducts tertiary desulfurization treatment on the coal gas. The output end of the micro-absorber is connected to the bottom end of the washing and demisting tower through a pipeline. The micro-absorber transports the coal gas through a pipeline to the washing and demisting tower. S5: There are three layers of demisting structures inside the washing and demisting tower. The bottom layer first intercepts and collects the desulfurization liquid transported by the micro-absorber through the packing of the primary demisting section into the bottom storage tank, and then uses the bottom desulfurization liquid circulation pump to circulate and send it above the packing of the primary demisting section for spraying and washing. S6: The coal gas passing through the packing of the primary demisting section will enter the middle layer of the washing and demisting tower. The packing of the secondary demisting section is washed and sprayed with ammonia water. The packing of the secondary demisting section is intercepted and collected into the middle layer storage tank, and then uses the bottom desulfurization liquid circulation pump to circulate and send it above the secondary demisting packing section for spraying and washing. S7: The packing of the upper layer's tertiary demisting section of the washing and demisting tower is washed with steam condensate. The coal gas after demisting is transported out through the pipeline at the top of the washing and demisting tower. The temperature of the steam condensate used in the packing of the upper layer's tertiary demisting section of the washing and demisting tower is 5°0C - 70°C. The coal gas will carry away some clean steam condensate, reduce ammonium polysulfide in the coal gas, increase the temperature of the coal gas, and ensure the water balance in the ammonium sulfate section.

2. The method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process according to claim 1, characterized in that, The number of the primary desulfurization absorption towers is two groups. The bottoms of the two groups of primary desulfurization absorption towers are connected to a regeneration tower through pipelines. The regeneration tower is used to recover and regenerate the desulfurization liquid transported from the primary desulfurization absorption tower, and after regeneration, it is transported back to the primary desulfurization absorption tower to continue the desulfurization treatment.

3. The method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process according to claim 1, characterized in that, The tower body of the secondary desulfurization absorption tower is divided into a desulfurization section and a regeneration section. The two streams of coal gas washed with desulfurization liquid in the two groups of primary desulfurization towers are collected together, and then two pipelines are set up to be respectively transported to the desulfurization section of the secondary desulfurization absorption tower and the micro-absorber.

4. The method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process according to claim 1, characterized in that, The outlet pipeline of the circulation pump set on the side of the washing and demisting tower has a branch, and the branch is connected to the primary desulfurization absorption tower or the secondary desulfurization absorption tower, and is used to transport the desulfurization liquid in the washing and demisting tower to the primary desulfurization absorption tower or the secondary desulfurization absorption tower for recycling.

5. The method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process according to claim 1, characterized in that, The desulfurization liquid in the primary desulfurization absorption tower and the secondary desulfurization absorption tower is made of complex iron or DDS desulfurization catalyst or a mixture of the two in any proportion.

6. The method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process according to claim 1, characterized in that, The ammonia water used in the middle layer of the washing and demisting tower is the ammonia water from the salt extraction section, the concentrated ammonia water from the ammonia distillation section, the concentrated ammonia water from the phosphoric acid washing ammonia section, or a mixture of any proportion of the above ammonia water.

7. The method for efficient desulfurization and mist capture of coke oven gas in a wet desulfurization process according to claim 1, characterized in that, The desulfurization liquid for spraying desulfurization in the micro-absorber comes from the regenerated desulfurization liquid of the regeneration tower supporting the primary desulfurization absorption tower or the regeneration section at the top of the secondary desulfurization absorption tower.

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