A system for preparing dimethyl sulfoxide by using coal chemical acid gas

Abstract

The utility model belongs to a kind of system for preparing dimethyl sulfoxide by coal chemical acid gas;Including acid gas pipeline, the acid gas pipeline is connected with the impurity removal and concentration unit for realizing to hydrogen sulfide is carried out impurity removal and concentration, the outlet of impurity removal and concentration unit and methanol pipeline are connected with dimethyl sulfide synthesis unit respectively, the outlet of dimethyl sulfide synthesis unit and hydrogen peroxide pipeline are connected with dimethyl sulfoxide synthesis unit respectively, the product outlet of dimethyl sulfoxide synthesis unit is connected with dimethyl sulfoxide storage tank;With the characteristics of short process flow, safe and reliable and waste utilization to acid gas, improve product added value.

Description

Technical Field

[0001] This invention belongs to the field of caprolactam production technology, and particularly relates to a system for preparing dimethyl sulfoxide using acidic gas from coal chemical industry. Background Technology

[0002] Low-temperature methanol washing produces acidic gas, a byproduct of coal chemical production. Its main components include hydrogen sulfide, carbon dioxide, nitrogen, carbonyl sulfide, and methanol, making it highly toxic and foul-smelling, and a significant source of pollution in the coal chemical industry. Traditional sulfur recovery units (for acid and sulfur production) directly use denitrified waste gas followed by combustion with oxygen for product preparation. This method is highly corrosive and uneconomical. Traditional dimethyl sulfoxide (DMSO) production employs a nitrogen oxide oxidation process. Sodium nitrite reacts with sulfuric / nitric acid to produce nitrogen tetroxide. Nitrogen tetroxide then reacts with oxygen to oxidize dimethyl sulfide (a DMSO intermediate) in an oxidation tower to produce crude dimethyl sulfide. The crude dimethyl sulfide contains dissolved nitrogen oxides and requires alkali washing for neutralization, followed by evaporation to remove waste salts. The desalted sulfoxide is then refined. Therefore, the traditional DMSO production process is lengthy and has poor safety. Utility Model Content

[0003] To overcome the above deficiencies, this utility model provides a system for preparing dimethyl sulfoxide using acidic gas from coal chemical industry, thereby solving the technical problems existing in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A system for producing dimethyl sulfoxide using coal chemical acid gas includes an acid gas pipeline connected to an impurity removal and concentration unit for removing and concentrating hydrogen sulfide. The outlet of the impurity removal and concentration unit and a methanol pipeline are connected to a dimethyl sulfide synthesis unit. The outlet of the dimethyl sulfide synthesis unit and a hydrogen peroxide pipeline are connected to the dimethyl sulfoxide synthesis unit. The product outlet of the dimethyl sulfoxide synthesis unit is connected to a dimethyl sulfoxide storage tank.

[0005] The beneficial effects of this invention are as follows: This invention utilizes a purification and concentration unit to remove impurities from and concentrate acidic gas to meet the synthesis requirements of dimethyl sulfide. Dimethyl sulfide is obtained by reacting methanol and concentrated hydrogen sulfide. Furthermore, dimethyl sulfide is obtained by reacting hydrogen peroxide from the hydrogen peroxide pipeline with dimethyl sulfide. Compared with traditional technologies, the above process has the advantages of shorter process flow, safety and reliability, waste utilization of acidic gas, and increased product added value.

[0006] Preferably, the impurity removal and concentration unit includes a drying tower for removing moisture from hydrogen sulfide, an acid gas pipeline connected to the inlet of the drying tower, an outlet of the drying tower connected to the first heat exchange channel of a cooler via a compressor, an outlet of the first heat exchange channel of the cooler connected to a hydrogen sulfide light phase removal distillation tower, a liquid phase outlet of the hydrogen sulfide light phase removal distillation tower connected to the hydrogen sulfide distillation tower, and a gas phase outlet at the top of the hydrogen sulfide distillation tower connected to a dimethyl sulfide synthesis unit via a second heat exchange channel of the cooler.

[0007] Preferably, the dimethyl sulfide synthesis unit includes a dimethyl sulfide synthesis reactor, the hydrogen sulfide inlet of which is connected to the outlet of the second heat exchange channel of the cooler, and the methanol inlet of which is connected to a methanol pipeline; the gas phase outlet of the dimethyl sulfide synthesis reactor is connected to a gas-liquid separator, the gas phase outlet of which is connected to the inlet of a sulfide light distillation column, the liquid phase outlet of which is connected to the inlet of an ether heavy distillation column, and the gas phase outlet of which is connected to the dimethyl sulfoxide synthesis unit via a preheater.

[0008] Preferably, the methanol pipeline is connected to the methanol inlet of the dimethyl sulfide synthesis reactor via a heater and a first channel of a heat exchanger, and the gas phase outlet of the dimethyl sulfide synthesis reactor is connected to the inlet of the gas-liquid separator via a second channel of a heat exchanger.

[0009] Preferably, the dimethyl sulfoxide synthesis unit includes a microreactor. The inlet of the microreactor is connected to the outlet of the preheater and a hydrogen peroxide pipeline, respectively. The outlet of the microreactor is connected to a sulfoxide dehydration tower. The liquid phase outlet of the sulfoxide dehydration tower is connected to a sulfoxide distillation tower. The liquid phase outlet of the sulfoxide distillation tower is connected to the inlet of the sulfoxide product distillation tower. The product outlet at the top of the sulfoxide product distillation tower is connected to a dimethyl sulfoxide storage tank. The liquid phase outlet at the bottom of the sulfoxide product distillation tower is connected to the dimethyl sulfoxide storage tank via a refining centrifuge.

[0010] Preferably, the gas phase outlet at the top of the hydrogen sulfide light distillation column, the liquid phase outlet at the bottom of the hydrogen sulfide distillation column, the gas phase outlet at the top of the sulfide light distillation column, and the liquid phase outlet at the bottom of the ether heavy distillation column are all connected to the sulfur recovery section of the coal chemical low-temperature methanol washing system.

[0011] Preferably, the liquid phase outlet at the bottom of the gas-liquid separator, the gas phase outlet of the sulfoxide dehydration tower and the sulfoxide distillation tower are respectively connected to the flash tower, the liquid phase outlet of the flash tower is connected to the water-coal slurry section of the coal blending system, and the gas phase outlet of the flash tower is connected to the sulfur recovery section of the coal chemical low-temperature methanol washing system.

[0012] Preferably, the microreactor is a microchannel reactor or a tubular reactor.

[0013] A system for preparing dimethyl sulfoxide (DMSO) from coal chemical acid gas, constructed according to the above scheme, utilizes an impurity removal and concentration unit to remove impurities and concentrate the acid gas to meet the synthesis requirements of dimethyl sulfide. Dimethyl sulfide is then obtained by reacting methanol with concentrated hydrogen sulfide. Further, dimethyl sulfide is obtained by reacting hydrogen peroxide from a hydrogen peroxide pipeline with the dimethyl sulfide. Specifically, this invention involves liquefying the acid gas after impurity removal under pressure, and then using low-temperature distillation technology to concentrate the hydrogen sulfide for use as a raw material in the production of dimethyl sulfide. Furthermore, by using hydrogen peroxide as an oxidant instead of nitrogen oxides and oxygen, there is no acid corrosion and no waste salt generated, making it safer and more environmentally friendly. Simultaneously, this invention can also recycle the waste gas and waste liquid produced in the dimethyl sulfoxide preparation system. This recycling process can return the waste gas and waste liquid to the coal chemical low-temperature methanol washing system or its preceding stages, thereby reducing the investment in waste gas and waste liquid treatment equipment in this invention, and reducing the waste gas and waste liquid treatment load in the original coal chemical low-temperature methanol washing system. It features a reasonable process design, safe and environmentally friendly operation, energy saving and consumption reduction, and increased product added value. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Legend: 1. Acid gas pipeline; 2. Methanol pipeline; 3. Hydrogen peroxide pipeline; 4. Dimethyl sulfoxide storage tank; 5. Drying tower; 6. Compressor; 7. Cooler; 8. Hydrogen sulfide light-light distillation tower; 9. Hydrogen sulfide distillation tower; 10. Methyl sulfide synthesis reactor; 11. Gas-liquid separator; 12. Sulfide light-light distillation tower; 13. Ether heavy-weight distillation tower; 14. Preheater; 15. Heater; 16. Heat exchanger; 17. Microreactor; 18. Sulfoxide dehydration tower; 19. Sulfoxide distillation tower; 20. Sulfoxide product distillation tower; 21. Refining centrifuge; 22. Dimethyl sulfoxide storage tank; 23. Sulfur recovery section; 24. Flash distillation tower; 25. Coal-water slurry section. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Reference Figure 1This utility model is a system for preparing dimethyl sulfoxide using coal chemical acid gas, including an acid gas pipeline 1, which is connected to a purification and concentration unit for removing and concentrating hydrogen sulfide. The outlet of the purification and concentration unit and the methanol pipeline 2 are respectively connected to a dimethyl sulfide synthesis unit. The outlet of the dimethyl sulfide synthesis unit and the hydrogen peroxide pipeline 3 are respectively connected to the dimethyl sulfoxide synthesis unit. The product outlet of the dimethyl sulfoxide synthesis unit is connected to a dimethyl sulfoxide storage tank 4. The essence of this invention lies in using the acidic gas in the acidic gas pipeline 1 as a raw material to produce high-value-added dimethyl sulfoxide, thereby turning waste into treasure and increasing the added value of the product. Furthermore, since the hydrogen sulfide content in the acidic gas in the acidic gas pipeline 1 is relatively low (not enough to meet the synthesis requirements of dimethyl sulfide) and the hydrogen sulfide content is unstable, a purification and concentration unit is used to purify and concentrate the acidic gas. The purification of the acidic gas includes the removal of moisture, carbon dioxide, and nitrogen, etc., to increase the concentration of hydrogen sulfide to not less than 99%, thereby meeting the requirements of subsequent production.

[0018] Furthermore, the impurity removal and concentration unit includes a drying tower 5 for removing moisture from hydrogen sulfide. An acid gas pipeline 1 is connected to the inlet of the drying tower 5. The outlet of the drying tower 5 is connected to the first heat exchange channel of the cooler 7 via a compressor 6. The outlet of the first heat exchange channel of the cooler 7 is connected to a hydrogen sulfide light-weight removal distillation tower 8. The liquid phase outlet of the hydrogen sulfide light-weight removal distillation tower 8 is connected to a hydrogen sulfide distillation tower 9. The gas phase outlet at the top of the hydrogen sulfide distillation tower 9 is connected to a dimethyl sulfide synthesis unit via a second heat exchange channel of the cooler 7. The impurity removal and concentration unit described in this invention includes a drying tower 5 for removing moisture from acidic gas, and a low-temperature distillation component for removing carbon dioxide and nitrogen using low-temperature distillation technology to concentrate hydrogen sulfide. Specifically, in this invention, a compressor 6 is used to pressurize the acidic gas after moisture removal and then condense it, laying the foundation for its entry into the subsequent low-temperature distillation component. The compressor 6 described in this invention can be a screw compressor or a diaphragm compressor, the compressor cooling medium is circulating water at 32-40°C, the pressurization pressure is ≥1.8MPa, and the refrigerant is propane or liquid ammonia.

[0019] Furthermore, the dimethyl sulfide synthesis unit includes a dimethyl sulfide synthesis reactor 10, the hydrogen sulfide inlet of the dimethyl sulfide synthesis reactor 10 is connected to the outlet of the second heat exchange channel of the cooler 7, and the methanol inlet of the dimethyl sulfide synthesis reactor 10 is connected to the methanol pipeline 2; the gas phase outlet of the dimethyl sulfide synthesis reactor 10 is connected to the gas-liquid separator 11, the gas phase outlet of the gas-liquid separator 11 is connected to the inlet of the sulfide light distillation column 12, the liquid phase outlet of the sulfide light distillation column 12 is connected to the inlet of the ether heavy distillation column 13, and the gas phase outlet of the ether heavy distillation column 13 is connected to the dimethyl sulfoxide synthesis unit through the preheater 14. This invention utilizes hydrogen sulfide and methanol as raw materials to synthesize dimethyl sulfide in a methyl sulfide synthesis reactor 10. Impurities are then removed to meet the requirements for subsequent production of dimethyl sulfoxide. Specifically, a gas-liquid separator 11 is used to separate moisture, and a sulfide light component removal distillation column 12 is used to remove light components, while a heavy component removal distillation column 13 is used to remove heavy components. This ensures that the final dimethyl sulfide has a purity of ≥99.5%, laying the foundation for subsequent production of dimethyl sulfoxide.

[0020] Furthermore, the methanol pipeline 2 is connected to the methanol inlet of the dimethyl sulfide synthesis reactor 10 via the heater 15 and the first channel of the heat exchanger 16, and the gas phase outlet of the dimethyl sulfide synthesis reactor 10 is connected to the inlet of the gas-liquid separator 11 via the second channel of the heat exchanger 16. This arrangement allows the methanol from the methanol pipeline 2 to be heated and completely vaporized, laying the foundation for rapid reaction within the dimethyl sulfide synthesis reactor 10; simultaneously, it cools the reaction synthesis gas at the gas phase outlet of the dimethyl sulfide synthesis reactor 10, achieving efficient utilization of thermal energy. Furthermore, the methanol in the methanol pipeline 2 in this invention can be liquid methanol, and this methanol must be of national standard grade one or higher.

[0021] Furthermore, the dimethyl sulfoxide synthesis unit includes a microreactor 17. The inlet of the microreactor 17 is connected to the outlet of the preheater 14 and the hydrogen peroxide pipeline 3, respectively. The outlet of the microreactor 17 is connected to the sulfoxide dehydration tower 18. The liquid phase outlet of the sulfoxide dehydration tower 18 is connected to the sulfoxide distillation tower 19. The liquid phase outlet of the sulfoxide distillation tower 19 is connected to the inlet of the sulfoxide product distillation tower 20. The product outlet at the top of the sulfoxide product distillation tower 20 is connected to the dimethyl sulfoxide storage tank 4. The liquid phase outlet at the bottom of the sulfoxide product distillation tower 20 is connected to the dimethyl sulfoxide storage tank 22 through a refining centrifuge 21. The microreactor 17 described in this invention carries out an oxidation reaction, and the products obtained from the oxidation reaction are crude dimethyl sulfoxide and water, with dimethyl sulfone as a byproduct. The reactants are dehydrated by setting up a sulfoxide dehydration tower 18, and impurities are removed by using a sulfoxide distillation tower 19 and a sulfoxide product distillation tower 20. At the same time, taking advantage of the different boiling points of dimethyl sulfoxide and dimethyl sulfone, the two are separated and enter the dimethyl sulfoxide storage tank 4 and the dimethyl sulfone storage tank 22 respectively.

[0022] Furthermore, the gas phase outlet at the top of the hydrogen sulfide light-light distillation column 8, the liquid phase outlet at the bottom of the hydrogen sulfide distillation column 9, the gas phase outlet at the top of the sulfide light-light distillation column 12, and the liquid phase outlet at the bottom of the ether heavy-light distillation column 13 are respectively connected to the sulfur recovery section 23 of the coal chemical low-temperature methanol washing system. This invention can also recover waste gas and waste liquid generated during the production process. The recovery mainly targets the waste gas and waste liquid generated in the distillation columns of the impurity removal and concentration unit and the dimethyl sulfide synthesis unit. Specifically, utilizing the characteristics of the aforementioned waste gas and waste liquid, they are fed into the sulfur recovery section 23 of the coal chemical low-temperature methanol washing system to achieve sulfur recovery.

[0023] Furthermore, the liquid phase outlet at the bottom of the gas-liquid separator 11, the gas phase outlets of the sulfoxide dehydration tower 18 and the sulfoxide distillation tower 19 are respectively connected to the flash tower 24. The liquid phase outlet of the flash tower 24 is connected to the coal-water slurry section 25 of the coal blending system, and the gas phase outlet of the flash tower 24 is connected to the sulfur recovery section 23 of the coal chemical low-temperature methanol washing system. This invention can also recover the liquid phase produced in the gas-liquid separator 11 and the waste liquid and waste gas produced in the dimethyl sulfoxide synthesis unit. During the recovery process, the liquid phase is flashed in the flash tower 24. The flashed gas phase is sent to the sulfur recovery section 23, and the flashed liquid phase is sent to the coal mill in the coal-water slurry section 25 as raw water for preparing coal-water slurry.

[0024] Furthermore, the microreactor 17 is a microchannel reactor or a tubular reactor.

[0025] This invention also provides a method for preparing dimethyl sulfoxide using acidic gas from coal chemical industry. The method involves: removing impurities and concentrating the acidic gas from the acidic gas pipeline 1 in the low-temperature methanol washing system of coal chemical industry; the hydrogen sulfide gas after removal and concentration and the methanol from the methanol pipeline 2 enter the dimethyl sulfide synthesis unit to generate dimethyl sulfide; and using the dimethyl sulfide and the hydrogen peroxide from the hydrogen peroxide pipeline 3 to enter the dimethyl sulfoxide synthesis unit to synthesize dimethyl sulfoxide.

[0026] This invention also provides a method for preparing dimethyl sulfoxide using acidic gas from coal chemical industry, the method comprising the following steps: Step 1: In the low-temperature methanol washing system of coal chemical industry, the acidic gas in the acidic gas pipeline 1 enters the drying tower 5 to remove moisture from the acidic gas. After moisture removal, the acidic gas enters the compressor 6 for compression. After compression, it enters the first heat exchange channel of the cooler 7 to be cooled into a liquid phase. The concentration of acidic gas in the acidic gas pipeline 1 is not less than 15%. The drying tower 5 is equipped with a molecular sieve for removing moisture from the acidic gas. The compressor 6 compresses the acidic gas to 1.8-2.2 MPa. Step 2: The liquid phase from Step 1 enters the hydrogen sulfide light-light-removal distillation column 8 for distillation to remove CO2 and N2; the liquid phase after distillation in the hydrogen sulfide light-light-removal distillation column 8 enters the hydrogen sulfide distillation column 9 for further distillation and purification; the purified gas phase enters the dimethyl sulfide synthesis reactor 10 through the outlet of the second heat exchange channel of the cooler 7; the heat source for the bottom of the hydrogen sulfide light-light-removal distillation column 8 is recycled water return or hot water, and the heat source for the bottom of the hydrogen sulfide distillation column 9 is recycled water return or hot water; the purity of the hydrogen sulfide entering the dimethyl sulfide synthesis reactor 10 is not less than 99%. Step 3: Methanol in methanol pipeline 2 is heated through the first channel of heater 15 and heat exchanger 16 and then enters dimethyl sulfide synthesis reactor 10. In dimethyl sulfide synthesis reactor 10, methanol and hydrogen sulfide undergo a catalytic reaction at high temperature to produce dimethyl sulfide and water. The heat transfer medium in heater 15 is molten salt or high-temperature heat transfer oil, and the temperature is 350–400°C. The reaction temperature in dimethyl sulfide synthesis reactor 10 is 350–400°C, and the pressure is 0.06–0.3 MPa. The reactor material is S321, and the catalyst is γ-Al2O3. Step 4: The reactants in the dimethyl sulfide synthesis reactor 10 are cooled by heat exchange in the second channel of the heat exchanger 16 to obtain crude sulfide and water. The crude sulfide and water are separated by the gas-liquid separator 11. The crude sulfide in the gas phase outlet of the gas-liquid separator 11 enters the sulfide light component removal distillation column 12 for distillation to remove light components. The material after removing light components enters the ether heavy component removal distillation column 13 for distillation. The gas phase after distillation in the ether heavy component removal distillation column 13 is dimethyl sulfide, which enters the microreactor 17. The distillation pressure in the sulfide light component removal distillation column 12 and the ether heavy component removal distillation column 13 is atmospheric pressure, and the distillation temperature is 38-50℃. Step 5: The hydrogen peroxide in the hydrogen peroxide pipeline 3 enters the microreactor 17 and oxidizes with the aforementioned dimethyl sulfide to produce dimethyl sulfoxide and water, with dimethyl sulfone as a byproduct. The above materials enter the sulfoxide dehydration tower 18 for dehydration treatment. The liquid phase at the bottom of the sulfoxide dehydration tower 18 enters the sulfoxide distillation tower 19 for distillation. The distilled liquid phase enters the sulfoxide product distillation tower 20 for distillation. The gas phase produced by distillation is dimethyl sulfoxide and is sent to the dimethyl sulfoxide storage tank 4. The liquid phase produced by distillation is centrifuged in the centrifuge 21 and then sent to the dimethyl sulfone storage tank 22. The oxidation reaction temperature in the microreactor 17 is 40-70℃, and the pressure is 0.2-0.5MPa. The oxidation heat transfer medium in the microreactor 17 is low-temperature water with a temperature of 7-12℃. The pressure in the sulfoxide dehydration tower 18 is -0.06 to -0.09MPa, and the temperature is 135-155℃. Step 6: The gas phase from hydrogen sulfide light distillation column 08, the gas phase from sulfur ether light distillation column 12, the liquid phase from hydrogen sulfide distillation column 9, and the liquid phase from ether heavy distillation column 13 are respectively fed into the sulfur recovery section 23 of the coal chemical low-temperature methanol washing system for sulfur recovery. Step 7: The liquid phase in the gas-liquid separator 11, the gas phase in the sulfoxide dehydration tower 18, and the gas phase in the sulfoxide distillation tower 19 are respectively fed into the flash tower 24 for flash evaporation. The liquid phase after flash evaporation is fed into the coal-water slurry section 25 of the coal blending system and used as water in the coal-water slurry. The gas phase after flash evaporation is fed into the sulfur recovery section 23 of the coal chemical low-temperature methanol washing system for sulfur recovery.

[0027] This invention is a complete reaction system in which acidic gas from the acidic gas pipeline 1 in the low-temperature methanol washing system of coal chemical industry is used as raw material to produce dimethyl sulfoxide. Dimethyl sulfone is produced as a byproduct during the production of dimethyl sulfoxide, thereby increasing the added value of the product. Furthermore, this invention recovers the cold energy in the hydrogen sulfide distillation column 9 through the cooler 7 and the heat energy in the dimethyl sulfide synthesis reactor 10 through the heat exchanger 16. These methods enable the effective utilization of heat (or cold energy) within the system, achieving energy savings. Even further, the dimethyl sulfoxide production system of this invention is integrated with the low-temperature methanol washing system of coal chemical industry. The waste gas and waste liquid produced in the production process can be recycled back to the low-temperature methanol washing system of coal chemical industry (or the preceding stage of the low-temperature methanol washing system) for recovery and treatment. This recovery and treatment not only recycles and reuses the waste gas or waste liquid according to its characteristics but also avoids the production of waste gas and waste liquid in this system, thus eliminating the need for a separate waste gas and waste liquid treatment system and reducing the treatment load on the waste gas and waste liquid in the low-temperature methanol washing system of coal chemical industry. Assuming no price is charged for the acidic gas, processing approximately 2200 m³ / h of acidic gas annually can produce 10,000 tons / year of dimethyl sulfoxide. With a selling price of approximately 12,000 yuan / ton for dimethyl sulfoxide, it is estimated that this will generate sales revenue of 120 million yuan / year and net profit of over 20 million yuan / year.

[0028] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A system for preparing dimethyl sulfoxide using coal chemical acid gas, comprising an acid gas pipeline (1), characterized in that: The acid gas pipeline (1) is connected to a purification and concentration unit for removing and concentrating hydrogen sulfide. The outlet of the purification and concentration unit and the methanol pipeline (2) are connected to the dimethyl sulfide synthesis unit. The outlet of the dimethyl sulfide synthesis unit and the hydrogen peroxide pipeline (3) are connected to the dimethyl sulfoxide synthesis unit. The product outlet of the dimethyl sulfoxide synthesis unit is connected to the dimethyl sulfoxide storage tank (4).

2. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 1, characterized in that: The impurity removal and concentration unit includes a drying tower (5) for removing water from hydrogen sulfide. An acid gas pipeline (1) is connected to the inlet of the drying tower (5). The outlet of the drying tower (5) is connected to the first heat exchange channel of the cooler (7) through a compressor (6). The outlet of the first heat exchange channel of the cooler (7) is connected to the hydrogen sulfide light phase distillation tower (8). The liquid phase outlet of the hydrogen sulfide light phase distillation tower (8) is connected to the hydrogen sulfide distillation tower (9). The gas phase outlet at the top of the hydrogen sulfide distillation tower (9) is connected to the dimethyl sulfide synthesis unit through the second heat exchange channel of the cooler (7).

3. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 2, characterized in that: The dimethyl sulfide synthesis unit includes a dimethyl sulfide synthesis reactor (10), the hydrogen sulfide inlet of the dimethyl sulfide synthesis reactor (10) is connected to the outlet of the second heat exchange channel of the cooler (7), the methanol inlet of the dimethyl sulfide synthesis reactor (10) is connected to the methanol pipeline (2); the gas phase outlet of the dimethyl sulfide synthesis reactor (10) is connected to the gas-liquid separator (11), the gas phase outlet of the gas-liquid separator (11) is connected to the inlet of the sulfide light distillation column (12), the liquid phase outlet of the sulfide light distillation column (12) is connected to the inlet of the ether heavy distillation column (13), and the gas phase outlet of the ether heavy distillation column (13) is connected to the dimethyl sulfoxide synthesis unit through the preheater (14).

4. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 3, characterized in that: The methanol pipeline (2) is connected to the methanol inlet of the dimethyl sulfide synthesis reactor (10) through the first channel of the heater (15) and the heat exchanger (16), and the gas phase outlet of the dimethyl sulfide synthesis reactor (10) is connected to the inlet of the gas-liquid separator (11) through the second channel of the heat exchanger (16).

5. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 3, characterized in that: The dimethyl sulfoxide synthesis unit includes a microreactor (17). The inlet of the microreactor (17) is connected to the outlet of the preheater (14) and the hydrogen peroxide pipeline (3). The outlet of the microreactor (17) is connected to the sulfoxide dehydration tower (18). The liquid phase outlet of the sulfoxide dehydration tower (18) is connected to the sulfoxide distillation tower (19). The liquid phase outlet of the sulfoxide distillation tower (19) is connected to the inlet of the sulfoxide product distillation tower (20). The product outlet at the top of the sulfoxide product distillation tower (20) is connected to the dimethyl sulfoxide storage tank (4). The liquid phase outlet at the bottom of the sulfoxide product distillation tower (20) is connected to the dimethyl sulfoxide storage tank (22) through a refining centrifuge (21).

6. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 5, characterized in that: The gas phase outlet at the top of the hydrogen sulfide light distillation column (8), the liquid phase outlet at the bottom of the hydrogen sulfide distillation column (9), the gas phase outlet at the top of the sulfide light distillation column (12), and the liquid phase outlet at the bottom of the ether heavy distillation column (13) are respectively connected to the sulfur recovery section (23) of the coal chemical low-temperature methanol washing system.

7. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 6, characterized in that: The liquid phase outlet at the bottom of the gas-liquid separator (11), the gas phase outlet of the sulfoxide dehydration tower (18) and the sulfoxide distillation tower (19) are respectively connected to the flash tower (24). The liquid phase outlet of the flash tower (24) is connected to the water-coal slurry section (25) of the coal blending system. The gas phase outlet of the flash tower (24) is connected to the sulfur recovery section (23) of the coal chemical low-temperature methanol washing system.

8. The system for preparing dimethyl sulfoxide using coal chemical acid gas according to claim 5, characterized in that: The microreactor (17) is a microchannel reactor or a tubular reactor.

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