Apparatus and method for reducing the attrition of fixed bed washed activated coke

Abstract

This invention relates to a device for reducing the pulverization of activated coke in a fixed-bed water-washing system. The device includes a desulfurization tower, a waste heat boiler, hot water pipes, cold water pipes, hot water pipe valves, a dilute sulfuric acid tank, and a concentrated sulfuric acid tank. The hot water pipes are connected to the waste heat boiler, and both the hot and cold water pipes are connected to a spray pipe. A hot water pipe flow meter and a hot water pipe valve are installed on the hot water pipes, as are a cold water pipe flow meter and a cold water pipe valve. A water thermometer is installed on the spray pipe. An upper flue gas pipe is located above the desulfurization tower. In this design, the activated coke is layered in the desulfurization tower according to its length-to-diameter ratio. The lower activated coke bears high pressure during use and is difficult to replace; using activated coke with a larger length-to-diameter ratio results in higher pressure resistance and a longer service life. The upper activated coke has a lower length-to-diameter ratio, resulting in lower pressure resistance. After pulverization, a portion can be replaced promptly, ensuring that the pulverized particles do not affect the overall permeability of the desulfurization tower and reducing the overall activated coke replacement cost.

Description

Technical Field

[0001] This invention relates to a device, specifically a device for reducing the pulverization of activated coke used in fixed-bed desulfurization, which can extend the service life of activated coke used in fixed-bed desulfurization, and belongs to the field of metallurgical environmental protection technology. Background Technology

[0002] Activated coke is a porous carbonaceous material. It is an activated coke adsorbent that has not been fully dry distilled or activated through a specific process. It has a large specific surface area and strong adsorption capacity.

[0003] Activated coke desulfurization technology is widely used in the treatment of pollutants in sintering and coking flue gas. Based on the arrangement of the activated coke, it is divided into fluidized bed and fixed bed processes. In fluidized bed processes, the activated coke is slowly pushed out for screening and renewal, thus the activated coke pulverization problem can be dynamically controlled. In fixed bed processes, the activated coke is filled into the desulfurization tower once and then replaced entirely every 2-3 years. Although its management and operation are simple, once the activated coke pulverizes inside the tower, it is difficult to remove, causing problems such as increased tower resistance and decreased desulfurization efficiency. When pulverization is severe, the activated coke needs to be replaced.

[0004] After activated coke desulfurization reaches saturation, SO3 is released from the activated coke and produced as sulfuric acid through heating or water washing regeneration. In fixed-bed regeneration using water washing, activated coke pulverization is unavoidable. Water washing regeneration requires activated coke to have high strength to withstand frequent rinsing by the regeneration solution.

[0005] Fixed-bed activated coke desulfurization technology is not widely used, and there is limited research on the pulverization problem of activated coke during its use. A search using keywords such as activated coke, desulfurization, and pulverization revealed that most patents describe activated coke desulfurization devices and activated coke manufacturing methods, which differ from the purpose of this patent. Patent CN201110111363.9 discloses a method to reduce activated coke loss, which involves repairing surface functional groups of moving-bed activated coke and spraying agents during transportation. This patent, however, is for fixed-bed activated coke and does not involve a transportation process, making it significantly different from the former. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by providing a device to reduce the pulverization of fixed-bed washed activated coke. The main purpose of this technical solution is to address the serious pulverization problem of fixed-bed washed activated coke during use by proposing a method to reduce the pulverization of fixed-bed washed activated coke and extend the service life of the washed activated coke used in fixed-bed desulfurization.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: an apparatus for reducing the pulverization of activated coke in a fixed-bed water washing system, comprising a desulfurization tower, a waste heat boiler, a hot water pipe, a cold water pipe, an upper flue gas pipe, a lower flue gas pipe, a hot water pipe flow meter, a cold water pipe flow meter, a water thermometer, a spray pipe, a hot water pipe valve, a cold water pipe valve, a dilute sulfuric acid tank, and a concentrated sulfuric acid tank; wherein the hot water pipe is connected to the waste heat boiler, the hot water pipe and the cold water pipe are connected together to the spray pipe, a hot water pipe flow meter and a hot water pipe valve are installed on the hot water pipe, a cold water pipe flow meter and a cold water pipe valve are installed on the cold water pipe, a water thermometer is installed on the spray pipe, an upper flue gas pipe is provided above the desulfurization tower, a lower flue gas pipe is provided below the desulfurization tower, and the dilute sulfuric acid tank and the concentrated sulfuric acid tank are respectively connected to the desulfurization tower through pipes.

[0008] As an improvement of the present invention, the device further includes an annular pipe, a multi-tube dust collector, a circulating fan, and a radiator. The annular pipe is connected to the lower part of the desulfurization tower, the multi-tube dust collector is connected between the circulating fan and the annular pipe, and the radiator is connected between the circulating fan and the upper part of the desulfurization tower.

[0009] As an improvement of the present invention, the desulfurization tower is provided with upper activated coke and lower activated coke arranged from top to bottom.

[0010] As an improvement of the present invention, an annular pipe is distributed on the lower outer ring of the desulfurization tower. The pipe diameter is 10cm, and 20 to 30 steel pipes with a diameter of 5cm are welded on the inner side along the horizontal direction. The steel pipes are fixed on the desulfurization tower and communicate with the inside of the desulfurization tower. The steel pipes are evenly distributed outside the desulfurization tower, which can make the cooling uniform.

[0011] As an improvement of the present invention, the activated coke is in the form of cylindrical particles. The upper activated coke has an aspect ratio of 1 to 4 and a filling height of 50 cm, while the lower activated coke has an aspect ratio of 5 to 10 and a filling height of 50 cm. Both types of activated coke contain more than 4% active components, have a wear resistance greater than 98%, a sulfur adsorption capacity greater than 80 mg / g, and a compressive strength greater than 200 N, resulting in excellent performance. The upper and lower activated coke sections are separated by their length-to-diameter ratio. Higher-strength activated coke is placed at the bottom, and lower-strength activated coke at the top. This is because the lower activated coke bears its own weight and is difficult to replace after pulverization; secondly, the upper activated coke bears less weight, and even if it pulverizes, it can be partially replaced, resulting in lower performance and production costs. Fixed-bed water washing and desorption processes cannot be set according to conventional strength and sulfur capacity indicators. Meeting national standards may not be suitable for this process, as national standards are designed for fluidized-bed thermal desorption processes, and there are currently no corresponding standards for activated coke used in fixed-bed water washing processes. Limiting the indicator range ensures that the activated coke does not pulverize under water washing, better matching the process. Common practices require an abrasion resistance greater than 96%, an active component of 2%, a compressive strength of 200N, and a sulfur capacity of 35mg / g. However, these indicators easily lead to pulverization in our process. A higher proportion of active component and higher sulfur capacity result in better desulfurization performance and fewer water washing cycles; higher abrasion resistance and compressive strength reduce pulverization caused by gravity, water washing impact, and thermal expansion and contraction.

[0012] As an improvement of the present invention, hot water from the hot water pipe and cold water from the cold water pipe are mixed in a ratio of 1:1 to 1:0.5 to produce warm water at 40 to 60°C. The activated coke is then washed with water through a spray pipe. Laboratory tests have shown that washing with water at 40 to 60°C can reduce the pulverization of activated coke caused by thermal expansion and contraction.

[0013] A method for reducing activated coke powdering in a fixed-bed water-washing system, the method comprising the following steps:

[0014] (1) Open the upper flue gas pipe and the lower flue gas pipe, and the desulfurization tower desulfurizes the flue gas;

[0015] (2) After desulfurization, close the upper flue gas duct and the lower flue gas duct;

[0016] (3) Turn on the circulating fan to extract the gas in the tower, use the radiator to cool the activated coke in the desulfurization tower for 30 minutes, and then turn off the circulating fan.

[0017] (4) Open the hot water pipe valve and the cold water pipe valve, adjust the hot water pipe flow meter and the cold water pipe flow meter, control the water temperature at 40-60℃, use the spray pipe to spray water to wash the activated coke for 10 minutes, close the hot water pipe valve and the cold water pipe valve, and after washing, the solution is stored in the dilute sulfuric acid tank.

[0018] (5) Draw concentrated sulfuric acid from the concentrated sulfuric acid tank to wash the activated carbon for 10 minutes, and then put the solution into the concentrated sulfuric acid tank.

[0019] (6) Draw dilute sulfuric acid from the dilute sulfuric acid tank to wash the activated carbon for 20 minutes. After washing, the solution is transferred to the concentrated sulfuric acid tank and the concentration of concentrated sulfuric acid is controlled at 3% to 7%.

[0020] (7) Open the cold water pipe valve and close the hot water pipe valve. Spray the activated coke with water for 10 minutes. After washing, the solution is stored in the dilute sulfuric acid tank.

[0021] (8) After cleaning, repeat step (1) and the desulfurization tower desulfurizes the flue gas again.

[0022] Compared with the prior art, the present invention has the following advantages: 1) In this scheme, the activated coke is layered in the desulfurization tower according to different length-to-diameter ratios. The activated coke in the lower part bears high pressure during use and is not easy to replace. Activated coke with a large length-to-diameter ratio has high pressure resistance and a long service life. The activated coke in the upper part has a low length-to-diameter ratio, so its pressure resistance is low. After pulverization, a portion of it can be replaced in time to ensure that the pulverized particles do not affect the overall air permeability of the desulfurization tower and reduce the overall activated coke replacement cost; 2) The scheme uses a circulating cooling device to reduce the temperature difference between the water and the activated coke, weaken the thermal expansion and contraction effect, and the rapid cooling helps to speed up the desulfurization tower switching time and improve desulfurization efficiency; 3) The scheme uses hot water and cold water generated by the waste heat boiler in the desulfurization front section to mix. The warm water used for cleaning is cheap and readily available, saving energy. Attached Figure Description

[0023] Figure 1 A schematic diagram of a method for reducing reactive carbonization;

[0024] Figure 2 This is a top view of a ring-shaped pipe.

[0025] In the diagram: 1-Waste heat boiler; 2-Hot water pipe; 3-Hot water pipe valve; 4-Hot water pipe flow meter; 5-Spray water pipe; 6-Water thermometer; 7-Cold water pipe flow meter; 8-Cold water pipe valve; 9-Cold water pipe; 10-Upper flue gas pipe; 11-Desulfurization tower; 12-Upper activated coke; 13-Lower activated coke; 14-Dilute sulfuric acid tank; 15-Ring pipe; 16-Lower flue gas pipe; 17-Multi-tube dust collector; 18-Circulating fan; 19-Radiator; 20-Concentrated sulfuric acid tank. Detailed implementation method:

[0026] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0027] Example 1: See Figure 1 , Figure 2An apparatus for reducing the pulverization of activated coke in a fixed-bed water washing system includes a desulfurization tower 11, a waste heat boiler 1, a hot water pipe 2, a cold water pipe 9, an upper flue gas pipe 10, a lower flue gas pipe 16, a hot water pipe flow meter 4, a cold water pipe flow meter 7, a water thermometer 6, a spray pipe 5, a hot water pipe valve 3, a cold water pipe valve 8; a dilute sulfuric acid tank 14 and a concentrated sulfuric acid tank 20; wherein the hot water pipe 2 is connected to the waste heat boiler 1, the hot water pipe 2 and the cold water pipe 9 are connected together to the spray pipe 5, the hot water pipe 2 is equipped with a hot water pipe flow meter 4 and a hot water pipe valve 3, the cold water pipe 9 is equipped with a cold water pipe flow meter 7 and a cold water pipe valve 8, the spray pipe 5 is equipped with a water thermometer 6, the upper flue gas pipe 10 is provided above the desulfurization tower 11, the lower flue gas pipe 16 is provided below the desulfurization tower 11, and the dilute sulfuric acid tank 14 and the concentrated sulfuric acid tank 20 are respectively connected to the desulfurization tower 11 through pipes. The device also includes an annular pipe 15, a multi-tube dust collector 17, a circulating fan 18, and a radiator 19. The annular pipe 15 is connected to the lower part of the desulfurization tower 11. The multi-tube dust collector 17 is connected between the circulating fan 18 and the annular pipe 15. The radiator 19 is connected between the circulating fan 18 and the upper part of the desulfurization tower 11. Inside the desulfurization tower 11, from top to bottom, there are upper activated coke 12 and lower activated coke 13. The annular pipe 15 is distributed on the lower outer ring of the desulfurization tower. The pipe diameter is 10cm, and 20-30 steel pipes with a diameter of 5cm are welded horizontally along its inner side. The steel pipes are fixed on the desulfurization tower and communicate with the inside of the desulfurization tower. The steel pipes are evenly distributed outside the desulfurization tower, which has a good effect and can make the cooling uniform. The activated coke consists of cylindrical granules. The upper activated coke has an aspect ratio of 1-4 and a filling height of 50cm, while the lower activated coke has an aspect ratio of 5-10 and a filling height of 50cm. Both types of activated coke contain more than 4% active components, have a wear resistance greater than 98%, a sulfur adsorption capacity greater than 80mg / g, and a compressive strength greater than 200N, exhibiting excellent performance. The upper and lower activated cokes are distinguished by their aspect ratio, with the higher-strength activated coke placed at the bottom and the lower-strength activated coke at the top. This is because the lower activated coke bears its own weight and is difficult to replace after pulverization; secondly, the upper activated coke bears less weight, and even if it pulverizes, it can be partially replaced, resulting in lower performance and production costs. Fixed-bed water washing and desorption processes cannot be set according to conventional strength and sulfur capacity indicators. Meeting national standards may not be suitable for this process because national standards are designed for fluidized-bed thermal desorption processes, and there are currently no corresponding standards for activated coke used in fixed-bed water washing processes. Limiting the indicator range ensures that the activated coke does not pulverize under water washing, allowing for better matching with the water washing process. The common practice is to require an abrasion resistance greater than 96%, an active component of 2%, a compressive strength of 200N, and a sulfur capacity of 35mg / g. However, these specifications are prone to pulverization in our process. A higher proportion of active components and a higher sulfur capacity result in better desulfurization performance and fewer washing cycles; higher abrasion resistance and compressive strength also reduce pulverization caused by gravity, washing impact, and thermal expansion and contraction.

[0028] Hot water from the hot water pipe and cold water from the cold water pipe are mixed in a ratio of 1:1 to 1:0.5 to produce warm water at 40 to 60 degrees Celsius. This warm water is then used to wash the activated coke through a spray pipe. Laboratory tests have shown that washing with water at 40 to 60 degrees Celsius can reduce the pulverization of activated coke caused by thermal expansion and contraction.

[0029] Example 2: See Figure 1 A method for reducing activated coke powdering in a fixed-bed water-washing system, the method comprising the following steps:

[0030] (1) Open the upper flue gas pipe and the lower flue gas pipe, and the desulfurization tower desulfurizes the flue gas;

[0031] (2) After desulfurization, close the upper flue gas duct and the lower flue gas duct;

[0032] (3) Turn on the circulating fan to extract the gas in the tower, use the radiator to cool the activated coke in the desulfurization tower for 30 minutes, and then turn off the circulating fan.

[0033] (4) Open the hot water pipe valve and the cold water pipe valve, adjust the hot water pipe flow meter and the cold water pipe flow meter, control the water temperature at 40-60℃, use the spray pipe to spray water to wash the activated coke for 10 minutes, close the hot water pipe valve and the cold water pipe valve, and after washing, the solution is stored in the dilute sulfuric acid tank.

[0034] (5) Draw concentrated sulfuric acid from the concentrated sulfuric acid tank to wash the activated carbon for 10 minutes, and then put the solution into the concentrated sulfuric acid tank.

[0035] (6) Draw dilute sulfuric acid from the dilute sulfuric acid tank to wash the activated carbon for 20 minutes. After washing, the solution is transferred to the concentrated sulfuric acid tank and the concentration of concentrated sulfuric acid is controlled at 3% to 7%.

[0036] (7) Open the cold water pipe valve and close the hot water pipe valve. Spray the activated coke with water for 10 minutes. After washing, the solution is stored in the dilute sulfuric acid tank.

[0037] (8) After cleaning, repeat step (1) and the desulfurization tower desulfurizes the flue gas again.

[0038] In this invention, the activated coke is specifically for flue gas desulfurization and is in the form of cylindrical particles; the hot water used in this invention is produced by the waste heat boiler in the pre-desulfurization stage, thus saving energy.

[0039] According to the inventors' research findings, the key factors affecting activated coke pulverization are its wear resistance, compressive strength, and desulfurization performance. The number of water washes and the water wash temperature also have a significant impact on the strength of activated coke. The strength of activated coke is related to its length-to-diameter ratio; the longer the ratio, the greater the strength. By controlling the water wash temperature and cooling the gas in the extraction tower through circulation, the cracking caused by thermal expansion and contraction of activated coke can be reduced.

[0040] In the process of completing this invention, the inventors conducted an in-depth study on the causes of pulverization of fixed-bed activated coke. Through research, they found that the pressure resistance and wear resistance of activated coke are different when the aspect ratio is different. Adding water washing after cleaning with dilute sulfuric acid makes the cleaning more thorough and can reduce the impact of salt substances on the desulfurization performance of activated coke. The test results are shown in the table below.

[0041] Table 1. Effect of aspect ratio on the pressure resistance of activated coke

[0042] Average compressive strength, N 45 50 82 90 111 134 168 196 212 235

[0043] Table 2 Effect of washing temperature on abrasion resistance

[0044] Abrasion resistance, % 97.97 98.09 98.3 97.95

[0045] Table 3 Desulfurization performance after cleaning activated coke using different methods

[0046] Acid-washed activated coke 722 532 30.7 Water-washed activated coke 732 541 41.6

[0047] Table 1 shows that the larger the aspect ratio, the greater the pressure resistance of activated coke; Table 2 shows that when the water washing temperature is 40-60℃, the wear resistance is relatively large, and the activated coke is not easy to pulverize at this temperature; Table 3 shows that the iodine value, specific surface area, and desulfurization value of water-washed activated coke are higher than those of acid-washed activated coke. Adding a water washing after acid washing is beneficial to maintaining the desulfurization capacity of activated coke, reducing the number of water washing cycles, and ultimately reducing pulverization.

[0048] Specific embodiment 1, taking the desulfurization of flue gas from a fixed-bed activated coke plant as an example, uses activated coke containing 5% catalytic active components, with an adsorption sulfur capacity of 85 mg / g, a wear resistance of 98.5%, a compressive strength of 207 N, an aspect ratio of 1 to 10, a circulating fan of type 4-72, a multi-tube dust collector of type TD-1T, a radiator of type LK45 plate-fin heat exchanger, valves of type 316L ball valves, a flow meter of type LWGY-DN50 liquid flow meter, and a water thermometer of type WSS bimetallic thermometer; all pipes are made of type 316L stainless steel.

[0049] When initially filling activated coke, a sieve is used for screening. Coke with a length-to-diameter ratio of 5 to 10 is filled at the bottom of the desulfurization tower to a height of 50 cm; coke with a length-to-diameter ratio of 1 to 4 is filled at the top of the desulfurization tower to a total height of 50 cm. The waste heat boiler uses hot water at 80°C and cold water at 25°C. The hot water and cold water are mixed at a ratio of 1:1, and the resulting water temperature is approximately 52.5°C.

[0050] A method for reducing activated coke powdering in a fixed-bed water-washing system includes the following steps:

[0051] Open the upper flue gas duct 10 and the lower flue gas duct 16, and the desulfurization tower 11 desulfurizes the flue gas; after desulfurization, close the upper flue gas duct 10 and the lower flue gas duct 16.

[0052] Turn on the circulating fan 18 to extract the gas in the tower, use the radiator 19 to cool the activated coke in the desulfurization tower 11 for 30 minutes, and then turn off the circulating fan 18.

[0053] Open hot water pipe valve 3 and cold water pipe valve 8, adjust hot water pipe flow meter 4 and cold water pipe flow meter 7 to control the water temperature between 40 and 60°C, spray the activated coke with water for 10 minutes using water spray pipe 5, then close hot water pipe valve 3 and cold water pipe valve 8. After washing, the solution enters the dilute sulfuric acid tank 14 for storage. Draw concentrated sulfuric acid from concentrated sulfuric acid tank 20 to wash the activated coke for 10 minutes, and the solution enters the concentrated sulfuric acid tank 20. Draw dilute sulfuric acid from dilute sulfuric acid tank 14 to wash the activated coke for 20 minutes, and the solution enters the concentrated sulfuric acid tank 20, controlling the concentrated sulfuric acid concentration to 3% to 7%. Open cold water pipe valve 8, close hot water pipe valve 3, spray the activated coke with water for 10 minutes, then close cold water pipe valve 8. After washing, the solution enters the dilute sulfuric acid tank for storage. After cleaning, one flue gas desulfurization process is completed. Repeat the above steps, and the desulfurization tower will desulfurize the flue gas again.

[0054] During the operation of the circulating fan, the powder in the multi-tube dust collector can be cleaned in a timely manner, reducing dust in the desulfurization tower. After the desulfurization tower has been running continuously for 6 to 8 months, the activated carbon in the upper 30cm of the desulfurization tower is replaced. After 15 to 20 months of operation, the activated carbon in the upper 20cm of the desulfurization tower is replaced. After 24 to 30 months of operation, the activated carbon is replaced entirely. During this period, the pressure difference of the desulfurization tower is significantly improved and stabilized at 1400pa to 1700pa. Compared with the current method of replacing the activated carbon entirely after two years of operation, this invention saves production costs.

[0055] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. An apparatus for reducing the pulverization of fixed bed water washed activated coke, characterized by, The system includes a desulfurization tower, a waste heat boiler, hot water pipes, cold water pipes, an upper flue gas pipe, a lower flue gas pipe, a hot water pipe flow meter, a cold water pipe flow meter, a water thermometer, a spray pipe, hot water pipe valves, cold water pipe valves, a dilute sulfuric acid tank, and a concentrated sulfuric acid tank. The hot water pipe is connected to the waste heat boiler, and the hot water pipe and cold water pipe are connected together to the spray pipe. The hot water pipe is equipped with a hot water pipe flow meter and a hot water pipe valve, the cold water pipe is equipped with a cold water pipe flow meter and a cold water pipe valve, and the spray pipe is equipped with a water thermometer. An upper flue gas pipe is located above the desulfurization tower, and a lower flue gas pipe is located below the desulfurization tower. The dilute sulfuric acid tank and the concentrated sulfuric acid tank are connected to the desulfurization tower through pipes. The device also includes an annular pipe, a multi-tube dust collector, a circulating fan, and a radiator. The annular pipe is connected to the lower part of the desulfurization tower, the multi-tube dust collector is connected between the circulating fan and the annular pipe, and the radiator is connected between the circulating fan and the upper part of the desulfurization tower. The desulfurization tower contains, from top to bottom, upper activated coke and lower activated coke; the upper activated coke has an aspect ratio of 1-4 and a filling height of 50cm, while the lower activated coke has an aspect ratio of 5-10 and a filling height of 50cm. The ring-shaped pipe is distributed on the lower outer ring of the desulfurization tower. The pipe diameter is 10cm. 20 to 30 steel pipes with a diameter of 5cm are welded horizontally on the inner side of the pipe. The steel pipes are fixed on the desulfurization tower and communicate with the inside of the desulfurization tower. The steel pipes are evenly distributed outside the desulfurization tower. The activated coke is in the form of cylindrical particles, containing a catalytically active component ratio greater than 4%, with a sulfur adsorption capacity greater than 80 mg / g, a wear resistance greater than 98%, and a compressive strength greater than 200 N. Hot water from the hot water pipes and cold water from the cold water pipes are mixed in a ratio of 1:1 to 1:0.5 to produce warm water at 40 to 60 degrees Celsius, which is then used to wash the activated coke through a spray pipe.

2. A method of reducing the attrition of fixed bed washed activated coke using the apparatus of claim 1, characterized in that, The method includes the following steps: Open the upper and lower flue gas ducts, and the desulfurization tower will desulfurize the flue gas; After desulfurization, close the upper flue gas duct and the lower flue gas duct; Turn on the circulating fan to extract the gas inside the tower, use the radiator to cool the activated coke inside the desulfurization tower for 30 minutes, and then turn off the circulating fan. Open the hot water pipe valve and the cold water pipe valve, adjust the hot water pipe flow meter and the cold water pipe flow meter to control the water temperature at 40~60℃, spray the activated coke with water for 10 minutes using the spray pipe, close the hot water pipe valve and the cold water pipe valve, and store the solution in the dilute sulfuric acid tank after water washing. Draw concentrated sulfuric acid from the concentrated sulfuric acid tank and wash the activated carbon for 10 minutes. The washed solution is then put back into the concentrated sulfuric acid tank. Draw dilute sulfuric acid from the dilute sulfuric acid tank and wash the activated carbon for 20 minutes. After washing, the solution is transferred to the concentrated sulfuric acid tank, and the concentration of concentrated sulfuric acid is controlled at 3%~7%. Open the cold water pipe valve and close the hot water pipe valve. Spray the activated coke with water for 10 minutes. After washing, the solution is stored in a dilute sulfuric acid tank. After cleaning, repeat step (1) to desulfurize the flue gas again.

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