Device for recycling sulfur dioxide in flue gas desulfurization desorption gas

Abstract

The utility model discloses a device for recycling sulfur dioxide in flue gas desulfurization desorption gas. Comprising a sulfur dioxide absorption tower, a clarifying tank connected with the sulfur dioxide absorption tower, a filter press connected with the clarifying tank, an ammonium sulfate clear liquid tank connected with the filter press and the clarifying tank, an acid preparation tank connected with the ammonium sulfate clear liquid tank, and an acid pickling tower for receiving mixed acid liquor from the acid preparation tank. According to the device for recycling sulfur dioxide in the flue gas desulfurization desorbed gas, sulfur dioxide in the desorbed gas can be effectively recycled, pollution to the atmosphere is reduced, the yield of ammonium sulfate is improved, generated ammonium sulfate clear liquid is matched with dilute acid generated in an acid making process and then recycled into a VOCs pickling tower system, and the aim of recycling sulfur dioxide in the desorbed gas is achieved. The dilute acid liquor generated in daily operation is treated, the consumption of the original concentrated sulfuric acid is reduced, the production cost can be reduced, and water introduction is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of biochemical waste gas treatment, and specifically relates to a device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas. Background Art

[0002] Sulfur dioxide and nitrogen oxides in the flue gas generated by coke oven heating are important sources of pollutants in coking production. Relevant national regulations require that end-of-pipe desulfurization and denitrification must be carried out.

[0003] The SO2 in the flue gas treated by the activated coke desulfurization and denitrification process used in the steel and coking industries is a weak acidic substance. After being absorbed by the activated coke, it is heated and decomposed in the desorption tower. The SO2 in the generated desorption gas can be removed by reacting with appropriate alkaline substances. Coking plants generally use the ammonia method to remove sulfur dioxide from the desorption gas. Ammonia desulfurization is to use a circulating liquid mixed with concentrated ammonia water to spray the desorption gas to absorb the SO2 in the desorption gas. The free ammonia sprayed in the ammonia desulfurization technology will form ammonium sulfite salt with SO2, and then form ammonium sulfate salt after oxidation. The produced ammonium sulfate product can also enter the ammonium sulfate system in the coking plant recovery workshop for treatment and utilization.

[0004] Ammonia desulfurization uses liquid absorbent to wash the analytical gas to remove SO2. The equipment used is relatively simple, easy to operate, and has high desulfurization efficiency. The ammonium sulfate byproduct produced is added to the ammonium sulfate system in the recovery workshop and then merged with the original ammonium sulfate solution in the saturator to participate in the concentration, crystallization, filtration, drying, and packaging processes. To avoid affecting the ammonium sulfate system, the quality of ammonia water is high, and the impurities in the liquid need to be treated to prevent impurities from entering the chemical ammonium sulfate system.

[0005] The VOCs pickling process in the chemical production workshop is to remove the alkaline substances (ammonia) in various VOCs tail gases in the washing area with an acidic solution. When the pickling solution reaches a certain concentration, a part of it will be discharged into the ammonium sulfate mother liquor tank for recovery, and the pickling tower will then be replenished with acid and water.

[0006] Concentrated sulfuric acid is usually added to the VOCs pickling process. The addition of concentrated sulfuric acid may cause the acid concentration and temperature in the pickling tower to be too high, which may cause serious corrosion to the pickling tower. In particular, the tower wall and tower bottom need to be inspected frequently, which may even lead to premature overhaul.

[0007] The acid-making process of desulfurization waste liquid in coking enterprises will produce a large amount of dilute sulfuric acid of about 12%. The desulfurization acid-making process generally adopts wet acid-making, dry acid-making and semi-dry acid-making processes. All three processes produce a large amount of dilute sulfuric acid, especially wet acid-making. The large amount of dilute acid makes it difficult to handle the ammonium sulfate process, which increases the burden on the coking industry. The excess dilute sulfuric acid is generally neutralized with sodium hydroxide and sent to the biochemical process, which increases the burden of biochemical treatment and deep treatment. Alternatively, the dilute sulfuric acid can be concentrated by membrane filtration, which requires a large amount of investment and operating expenses.

[0008] For example, the patent document with publication number CN103736385A discloses a system and method for recovering sulfur dioxide from flue gas. Among them, the system for recovering sulfur dioxide from flue gas includes: a high-efficiency pipeline reaction desulfurization tower, which is used to make flue gas containing sulfur dioxide contact with zinc oxide slurry in countercurrent to obtain post-contact liquid and tail gas; a vacuum belt filter, which is connected to the high-efficiency pipeline reaction desulfurization tower and is used to filter press at least a part of the post-contact liquid to obtain filtrate and filter cake; and an acid hydrolysis reaction tank, which is connected to the vacuum belt filter and is used to acid hydrolyze and desorb the filter cake to obtain sulfur dioxide gas. The system can effectively achieve the treatment and recovery of sulfur dioxide in smelting flue gas, and it is economical, scientific and environmentally friendly. The technical solution disclosed in the patent document also cannot solve the technical problems recorded above. Utility Model Content

[0009] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas, the purpose of which is to reduce costs and reduce the introduction of moisture.

[0010] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas, including a sulfur dioxide absorption tower, a clarification tank connected to the sulfur dioxide absorption tower, a filter press connected to the clarification tank, an ammonium sulfate clear liquid tank connected to the filter press and the clarification tank, an acid preparation tank connected to the ammonium sulfate clear liquid tank, and a pickling tower for receiving mixed acid from the acid preparation tank.

[0011] A packing mist catching layer is arranged on the top of the pickling tower.

[0012] A jet-type venturi absorber for receiving sulfur-containing analytical gas is arranged on the top of the sulfur dioxide absorption tower.

[0013] A delivery pump is arranged between the sulfur dioxide absorption tower and the clarification tank, and the delivery pump is connected to the sulfur dioxide absorption tower and the clarification tank.

[0014] A sludge pump is arranged between the clarification tank and the filter press, and the sludge pump is connected to the clarification tank and the filter press.

[0015] A clear liquid pump is arranged between the ammonium sulfate clear liquid tank and the acid preparation tank, and the clear liquid pump is connected to the ammonium sulfate clear liquid tank and the acid preparation tank.

[0016] A cleaning liquid pump is arranged between the pickling tower and the cleaning liquid tank, and the cleaning liquid pump is connected to the pickling tower and the cleaning liquid tank. Production water and 12% dilute sulfuric acid are added to the cleaning liquid tank, and the acid concentration of the cleaning liquid transported to the pickling tower is 2-5%.

[0017] The concentration of the dilute sulfuric acid added to the acid preparation tank is 12%. After the ammonium sulfate clear solution added to the acid preparation tank is combined with the dilute sulfuric acid, the acid concentration of the combined acid solution is 1-5%.

[0018] The utility model discloses a device for recovering and treating sulfur dioxide in the flue gas desulfurization analysis gas, which can effectively recover sulfur dioxide in the analysis gas, reduce pollution to the atmosphere and increase the yield of ammonium sulfate. The generated ammonium sulfate clear liquid is combined with the dilute acid generated in the acid making process and then recovered into the VOCs acid washing tower system, which not only treats the dilute acid liquid generated in daily operation, but also reduces the consumption of original concentrated sulfuric acid, thereby reducing production costs and reducing the introduction of moisture. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This specification includes the following drawings, which show the following contents:

[0020] Figure 1 It is a structural schematic diagram of an ammonium sulfate mother liquor preparation system;

[0021] Figure 2 It is a partial structural schematic diagram of a device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas according to the utility model;

[0022] The markings in the figure are: 1. Sulfur dioxide absorption tower; 2. Clarification tank; 3. Filter press; 4. Ammonium sulfate clear liquid tank; 5. Acid preparation tank; 6. Pickling tower; 7. Packing mist capture layer; 8. Jet Venturi absorber; 9. Absorption column; 10. Reaction tank; 11. Circulating washing pump; 12. Sludge pump; 13. Clear liquid pump; 14. Delivery pump; 15. Pickling pump; 16. Cleaning liquid tank; 17. Water pump. DETAILED DESCRIPTION

[0023] The specific implementation methods of the utility model are further explained in detail below with reference to the accompanying drawings through the description of embodiments, with the aim of helping technicians in the field to have a more complete, accurate and in-depth understanding of the concept and technical solution of the utility model and facilitating its implementation.

[0024] like Figure 1 and Figure 2As shown, the utility model provides a device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas, comprising a sulfur dioxide absorption tower 1, a clarification tank 2 connected to the sulfur dioxide absorption tower 1, a filter press 3 connected to the clarification tank 2, an ammonium sulfate clear liquid tank 4 connected to the filter press 3 and the clarification tank 2, an acid preparation tank 5 connected to the ammonium sulfate clear liquid tank 4, and a pickling tower 6 connected to the acid preparation tank 5 and used for receiving a mixed acid solution from the acid preparation tank 5, wherein the mixed acid solution is a mixture of dilute sulfuric acid and ammonium sulfate clear liquid or ammonium sulfate mother liquor.

[0025] Specifically, if Figure 1 As shown, a jet venturi absorber 8 for receiving sulfur-containing analytical gas is arranged at the top of the sulfur dioxide absorption tower 1, and a reaction tank 10 of the sulfur dioxide absorption tower 1 is connected to the jet venturi absorber 8 via a circulating washing pump 11. The concentration of ammonia water added to the sulfur dioxide absorption tower 1 is 20%, and the ammonia water can be ammonia water (concentration of 20%) produced by the phosphoric acid washing ammonia system of the coking plant itself, or ammonia water (concentration of 20%) can be purchased from outside to ensure the quality of ammonium sulfate and reduce the introduction of water.

[0026] In the utility model, for the preparation of ammonium sulfate mother liquor after desulfurization and denitrification of coke oven flue gas, an ammonia absorption process is adopted, concentrated ammonia water is added to the circulating liquid of the sulfur dioxide absorption tower 1, and the sulfur-containing analysis gas treated by the desulfurization and denitrification analysis tower enters the jet venturi absorber 8 at the top of the sulfur dioxide absorption tower 1 through the inlet pipe, and the circulating liquid and the analysis gas are fully contacted to absorb and remove most of the smoke and sulfur dioxide in the analysis gas.

[0027] The analytical gas from which sulfur dioxide is removed in the sulfur dioxide absorption tower 1 passes through the absorption column 9 of the sulfur dioxide absorption tower 1 to remove the entrained circulating liquid and then returns to the desulfurization and denitration adsorption tower. The circulating liquid that absorbs sulfur dioxide is blown into the reaction tank 10 of the sulfur dioxide absorption tower 1 by a blower to react the ammonium sulfite in the circulating liquid to prepare an ammonium sulfate solution of a certain concentration and then sent to the clarification tank 2. The sludge at the bottom of the clarification tank 2 (mainly the carbon powder of activated coke) is transported to the filter press 3 for dehydration through the sludge pump 12. The filtrate produced in the filter press 3 returns to the ammonium sulfate clear liquid tank 4, and the carbon powder sludge is sent to the coal blending. The clear liquid on the top of the clarification tank 2 flows to the ammonium sulfate clear liquid tank 4 by overflow. After the clear liquid tank reaches a certain liquid level, it is pumped to the ammonium sulfate mother liquid tank or the acid blending tank 5 in the plant area through the clear liquid pump 13.

[0028] like Figure 1 As shown, a delivery pump 14 is provided between the sulfur dioxide absorption tower 1 and the clarification tank 2, and the delivery pump 14 is connected to the sulfur dioxide absorption tower 1 and the clarification tank 2. A sludge pump 12 is provided between the clarification tank 2 and the filter press 3, and the sludge pump 12 is connected to the clarification tank 2 and the filter press 3.

[0029] like Figure 2As shown, a clear liquid pump 13 is arranged between the ammonium sulfate clear liquid tank 4 and the acid preparation tank 5 , and the clear liquid pump 13 is connected to the ammonium sulfate clear liquid tank 4 and the acid preparation tank 5 .

[0030] like Figure 2 As shown, the bottom of the pickling tower 6 is connected to the pickling pump 15, and the concentration of the dilute sulfuric acid added to the acid preparation tank 5 is about 10-14%, preferably 12%.

[0031] The dilute acid pump installed in the underground tank of the acid-making workshop replenishes the dilute acid into the ammonium sulfate mother liquor tank or the acid preparation tank 5 of the pickling tower 6 of the VOCs treatment device through a pipeline. Part of the ammonium sulfate mother liquor sent from the desulfurization and denitrification section is sent to the acid preparation tank 5 of the pickling tower 6 of the VOCs treatment device in the area through a pipeline, and part is sent to the ammonium sulfate mother liquor tank. The mixed acid prepared in the acid preparation tank 5 is used to replenish the pickling tower 6. When the concentration of the mother liquor in the pickling tower 6 is high, it is replenished into the mother liquor tank of the ammonium sulfate section and enters the ammonium sulfate saturator system to circulate and generate ammonium sulfate products.

[0032] The acid concentration in the acid preparation tank 5 of the pickling tower 6 is maintained at 3-5% by adding ammonium sulfate mother liquor from the desulfurization and denitration section. If it exceeds 5%, it will cause corrosion of the pickling tower 6 and the associated pipeline equipment.

[0033] like Figure 2 As shown, a packed mist-collecting layer 7 is provided on the top of the pickling tower 6 to collect the circulating liquid that may be entrained in the VOCs gas after washing. To prevent the packed mist-collecting layer 7 from being blocked, a cleaning liquid prepared with dilute sulfuric acid and produced water is sprayed regularly to clean the packed mist-collecting layer 7.

[0034] like Figure 2 As shown, a water pump 17 is arranged between the pickling tower 6 and the cleaning liquid tank 16, and the water pump 17 is connected to the pickling tower 6 and the cleaning liquid tank 16. Production water and dilute sulfuric acid with a concentration of 12% are added to the cleaning liquid tank 16. The production water and dilute sulfuric acid in the cleaning liquid tank 16 are mixed to form a cleaning liquid. The acid concentration of the cleaning liquid is 2-5%. The water pump 17 transports the cleaning liquid to the pickling tower 6.

[0035] The device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas of the above structure has the following advantages:

[0036] 1. A mist capture layer is set at the top of the pickling tower 6, which can effectively reduce the pickling circulating liquid from entering the alkali washing tower of the next process through mist entrainment, causing the subsequent VOCs gas to contain excessive ammonia.

[0037] 2. The sulfur dioxide in the analytical gas is effectively recovered, which reduces the pollution to the atmosphere and increases the output of ammonium sulfate. At the same time, the specific gravity of the circulating washing liquid in the sulfur dioxide absorption tower is increased to more than 1.2 due to the swelling of the ammonium sulfate section and the inability to discharge the ammonium sulfate clear liquid to the ammonium sulfate section in time, so that part of the sulfur dioxide in the analytical gas returns to the adsorption tower.

[0038] 3. Reduce the consumption of production water added to the VOCs pickling tower 6.

[0039] 4. Regularly clean the mist collecting layer on the top of the VOCs pickling tower 6 to reduce the resistance of the pickling tower 6, while reducing the concentration of the circulating liquid and extending the circulation period. At the same time, even if the cleaning liquid is entrained into the subsequent alkaline washing process through the mist, no ammonia will return to the VOCs gas.

[0040] 5. The dilute acid produced by the acid production process is recovered into the VOCs pickling tower 6 system, which not only treats the dilute acid liquid produced by daily operation, but also reduces the consumption of original concentrated sulfuric acid.

[0041] 6. Because the dilute sulfuric acid from the acid-making section is mixed with the ammonium sulfate mother liquor and production water from the desulfurization and denitrification section and then fed into the pickling tower 6, it will not cause corrosion to the pickling tower 6, thus avoiding frequent maintenance and welding repairs, and extending the equipment maintenance cycle.

[0042] 7. At present, the coking industry uses wet acid production, dry acid production and semi-dry acid production in the desulfurization and acid production section, all of which produce a large amount of dilute sulfuric acid, especially wet acid production. Using dilute sulfuric acid for VOCs pickling tower 6 system for treatment can effectively reduce the burden of desulfurization and acid production in the coking industry, and reduce the heavy burden of using dilute acid membrane concentration or using sodium hydroxide lye to neutralize the dilute acid and then send it to biochemical treatment and deep treatment.

[0043] Example

[0044] A coking company produces 30 tons of concentrated sulfuric acid and 3 tons of dilute sulfuric acid per day, with an acid concentration of 12%. Every day, 6 tons of ammonium sulfate mother liquor sent from the desulfurization and denitrification section are added to make the acid concentration reach about 4-5%, which is used to add to the VOCs pickling tower 6 of the ammonium sulfate section as the pickling circulating liquid. It can replace the production water consumption of 5-6 tons / day, and at the same time avoid the liquid swelling of the ammonium sulfate saturator system. When the ammonium sulfate crystal ratio in the mother liquor of the VOCs pickling tower 6 reaches 10-15%, it is replenished into the mother liquor tank of the ammonium sulfate section. The pH of the mother liquor of the VOCs pickling tower 6 is maintained at 3-6. The mist catching layer on the top of the pickling tower 6 is sprayed and cleaned once a day, and the amount of cleaning liquid is 1m 3 .

[0045] The above is an exemplary description of the utility model in conjunction with the accompanying drawings. Obviously, the specific implementation of the utility model is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the utility model; or the above concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. A device for recovering and treating sulfur dioxide in flue gas desulfurization analysis gas, characterized in that: The invention comprises a sulfur dioxide absorption tower, a clarification tank connected to the sulfur dioxide absorption tower, a filter press connected to the clarification tank, an ammonium sulfate clear liquid tank connected to the filter press and the clarification tank, an acid preparation tank connected to the ammonium sulfate clear liquid tank, and an acid washing tower for receiving mixed acid from the acid preparation tank.

2. The device for recovering sulfur dioxide from flue gas desulfurization analysis gas according to claim 1 is characterized in that: A packing mist catching layer is arranged on the top of the pickling tower.

3. The device for recovering sulfur dioxide in flue gas desulfurization analysis gas according to claim 1 is characterized in that: A jet-type venturi absorber for receiving sulfur-containing analytical gas is arranged on the top of the sulfur dioxide absorption tower.

4. The device for recovering sulfur dioxide from flue gas desulfurization analysis gas according to any one of claims 1 to 3, characterized in that: A delivery pump is arranged between the sulfur dioxide absorption tower and the clarification tank, and the delivery pump is connected to the sulfur dioxide absorption tower and the clarification tank.

5. The device for recovering sulfur dioxide from flue gas desulfurization analysis gas according to any one of claims 1 to 3, characterized in that: A sludge pump is arranged between the clarification tank and the filter press, and the sludge pump is connected to the clarification tank and the filter press.

6. The device for recovering sulfur dioxide from flue gas desulfurization analysis gas according to any one of claims 1 to 3, characterized in that: A clear liquid pump is arranged between the ammonium sulfate clear liquid tank and the acid preparation tank, and the clear liquid pump is connected to the ammonium sulfate clear liquid tank and the acid preparation tank.

7. The device for recovering sulfur dioxide from flue gas desulfurization analysis gas according to any one of claims 1 to 3, characterized in that: A cleaning liquid pump is arranged between the pickling tower and the cleaning liquid tank, and the cleaning liquid pump is connected to the pickling tower and the cleaning liquid tank. Production water and 12% dilute sulfuric acid are added to the cleaning liquid tank, and the acid concentration of the cleaning liquid transported to the pickling tower is 2-5%.

8. The device for recovering sulfur dioxide from flue gas desulfurization analysis gas according to any one of claims 1 to 3, characterized in that: The concentration of the dilute sulfuric acid added to the acid preparation tank is 12%. After the ammonium sulfate clear solution added to the acid preparation tank is combined with the dilute sulfuric acid, the acid concentration of the combined acid solution is 1-5%.

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