A tail gas treatment device for dcs production

Abstract

The utility model discloses a kind of tail gas treatment devices for bischlorosulfonimide production, it is related to tail gas processing field, and it includes: A line unit, it includes primary water absorption tower, secondary water absorption tower, tertiary water absorption tower, quaternary water absorption tower and bisulfite reaction tank, the primary water absorption tower gas phase outlet is connected with the secondary water absorption tower gas phase inlet, the secondary water absorption tower gas phase outlet is connected with the tertiary water absorption tower gas phase inlet, the tertiary water absorption tower gas phase outlet is connected with the bisulfite reaction tank gas phase inlet, the primary water absorption tower is used to receive the mixed gas of hydrogen chloride and sulfur dioxide, and basic absorbent is filled in the bisulfite reaction tank;B line unit, it includes the hydrochloric acid purification tank connected with the primary water absorption tower liquid phase outlet of the A line unit.The utility model can efficiently separate hydrogen chloride and sulfur dioxide in tail gas and produce high-purity byproduct.

Description

Technical Field

[0001] This utility model relates to the field of exhaust gas treatment, specifically to an exhaust gas treatment device for the production of dichlorosulfonamide. Background Technology

[0002] Lithium bisfluorosulfonyl imide (LiFSI), as a lithium salt electrolyte for lithium-ion batteries, is regarded as a key next-generation material to replace lithium hexafluorophosphate (LiPF6) due to its advantages such as high thermal stability, excellent electrical conductivity and good compatibility with electrode materials.

[0003] In the industrial production of LiFSI, the process typically involves the synthesis, fluorination, and lithiation of the bischlorosulfonylimide intermediate. The synthesis of bischlorosulfonylimide primarily uses thionyl chloride, chlorosulfonic acid, and aminosulfonic acid as raw materials, and this reaction generates a large amount of mixed sulfur dioxide and hydrogen chloride in the tail gas. Currently, the industry commonly uses water to absorb hydrogen chloride to produce hydrochloric acid as a byproduct, followed by treating the residual sulfur dioxide with alkaline substances for tail gas treatment. However, this process results in hydrochloric acid containing a high concentration of dissolved sulfur dioxide, and the sulfur dioxide gas also contains residual hydrogen chloride.

[0004] The existing processing methods result in low purity and poor quality of the byproducts hydrochloric acid and sulfite, which cannot be effectively utilized and sold as qualified chemical products, creating a large amount of waste that needs further processing, increasing overall production costs and environmental burden. Utility Model Content

[0005] This invention aims to address one of the technical problems in related technologies to a certain extent. To this end, this invention provides a tail gas treatment device for the production of dichlorosulfonylimide, which can efficiently separate hydrogen chloride and sulfur dioxide from the tail gas and produce high-purity by-products, thus realizing the resource utilization of waste gas.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A tail gas treatment device for the production of dichlorosulfonylimide includes: Unit A includes a primary water absorption tower, a secondary water absorption tower, a tertiary water absorption tower, a quaternary water absorption tower, and a bisulfite reaction tank. The gas phase outlet of the primary water absorption tower is connected to the gas phase inlet of the secondary water absorption tower, the gas phase outlet of the secondary water absorption tower is connected to the gas phase inlet of the tertiary water absorption tower, and the gas phase outlet of the tertiary water absorption tower is connected to the gas phase inlet of the bisulfite reaction tank. The primary water absorption tower is used to receive a mixture of hydrogen chloride and sulfur dioxide. The bisulfite reaction tank is filled with an alkaline absorbent. Line B includes a hydrochloric acid purification tank connected to the liquid phase outlet of the primary water absorption tower of Line A.

[0007] In this application, a primary water absorption tower is used to achieve initial separation of hydrogen chloride and sulfur dioxide. Secondary, tertiary, and quaternary water absorption towers then remove hydrochloric acid gas from the sulfur dioxide gas, avoiding the problem of cross-contamination between the two gases in traditional processes, thus ensuring that the produced sulfur dioxide is a high-purity product. The bisulfite reaction tank is filled with an alkaline absorbent, which reacts with the incoming sulfur dioxide to form bisulfite. Hydrochloric acid is further purified through a B-line unit to remove sulfur dioxide. This tail gas treatment device, through multi-stage treatment, completely converts the tail gas generated during the production of dichlorosulfonylimide into commercially valuable high-purity hydrochloric acid and industrial-grade bisulfite, realizing a transformation from waste treatment to resource recovery and improving the process's economic efficiency. Furthermore, the reaction process in the tail gas treatment device is based on water absorption, a low-cost operation, requiring no complex or expensive equipment or reagents, resulting in lower investment and operating costs and easy industrial-scale promotion.

[0008] Optionally, the A-line unit also includes a control unit. The primary water absorption tower, the secondary water absorption tower, the tertiary water absorption tower, the quaternary water absorption tower, and the bisulfite reaction tank are all equipped with level gauges for monitoring the material level inside. The level gauges are electrically connected to the control unit, and each absorption tower is equipped with a liquid pump.

[0009] The gas phase inlet of the fourth-stage water absorption tower is connected to the gas phase outlet of the third-stage water absorption tower, and the gas phase outlet of the fourth-stage water absorption tower is connected to the bisulfite reaction tank. In other words, the fourth-stage water absorption tower is located after the third-stage tower and before the reaction tank in the gas path. Even if the purity of the gas exiting the third-stage water absorption tower is poor, the fourth-stage water absorption tower can compensate, ensuring that the purity of the sulfur dioxide gas entering the bisulfite reaction tank remains high. It should be noted that the fourth-stage water absorption tower is not always in use, but serves as a backup unit. Its operation depends on the purity of the sulfur dioxide gas exiting the third-stage water absorption tower. The fourth-stage tower contains low-temperature fresh water, which performs a final water wash on sulfur dioxide gas that does not meet the purity standards. Utilizing the property that hydrogen chloride is highly soluble in water at low temperatures, it deeply removes residual hydrogen chloride impurities.

[0010] The gas phase outlet of the fourth-stage water absorption tower is connected to the bisulfite reaction tank. The gas phase outlet of the third-stage water absorption tower is connected to the gas phase inlet of the fourth-stage water absorption tower and the gas phase inlet of the bisulfite reaction tank through pipelines, forming a switchable flow path. The control unit switches the flow path according to the detection results of the online gas analyzer, and directs the gas in the third-stage water absorption tower to the fourth-stage water absorption tower or the bisulfite reaction tank.

[0011] An online gas analyzer is installed at the gas phase outlet of a three-stage water absorption tower to monitor the mass ratio of sulfur dioxide to hydrogen chloride in the gas in real time. The online gas analyzer and control unit are connected by electrical signals to form a control structure from detection to execution.

[0012] Optionally, an online gas analyzer is installed between the three-stage water absorption tower and the four-stage water absorption tower, and the online gas analyzer is electrically connected to the control unit; a first gas valve is installed at the gas phase inlet of the four-stage water absorption tower, and a second gas valve is installed between the three-stage water absorption tower and the bisulfite reaction tank, both the first and second gas valves being electrically connected to the control unit; the online gas analyzer is used to detect the mass ratio of sulfur dioxide to hydrogen chloride in the gas output from the gas phase outlet of the three-stage water absorption tower; when the mass ratio is ≥100, the control unit closes the first gas valve; when the mass ratio is <100, the control unit opens the first gas valve.

[0013] When the online gas analyzer detects a mass ratio greater than or equal to 100, it indicates that the sulfur dioxide gas purity has met the standard. The control unit then closes the first gas valve controlling the opening and closing of the gas path of the fourth-stage water absorption tower and opens the second gas valve directly connecting the third-stage water absorption tower to the bisulfite reaction tank, allowing the qualified sulfur dioxide gas to directly enter the bisulfite reaction tank. Conversely, when the mass ratio is less than 100, it indicates that the sulfur dioxide gas purity is insufficient. The first gas valve controlling the opening and closing of the gas path of the fourth-stage water absorption tower and the second gas valve directly connecting to the bisulfite reaction tank are opened, forcing the gas into the fourth-stage water absorption tower to remove residual hydrogen chloride, ensuring that only high-purity sulfur dioxide gas can ultimately enter the bisulfite reaction tank.

[0014] Optionally, the gas phase inlet of the hydrochloric acid purification tank is connected to a gas source, and compressed air is introduced into the hydrochloric acid purification tank for stripping. A level gauge is used to monitor the material level in the tank, and the level gauge is electrically connected to the control unit.

[0015] The gas phase inlet of the hydrochloric acid purification tank is connected to an external gas source via a pipeline. When compressed air supplied by the gas source is introduced into the crude hydrochloric acid solution in the hydrochloric acid purification tank, the sulfur dioxide dissolved in the solution will spontaneously cross the gas-liquid interface due to its extremely high equilibrium partial pressure in the gas phase, diffuse from the liquid phase into the compressed air bubbles, and be carried away from the solution.

[0016] Optionally, the B-line unit further includes a control unit and a hydrochloric acid tank for storing finished hydrochloric acid. The liquid phase inlet of the hydrochloric acid tank is connected to the liquid phase outlet of the hydrochloric acid purification tank via a pipeline. The hydrochloric acid purification tank is equipped with a level gauge for monitoring the material level inside the tank. An online hydrochloric acid analyzer is installed between the hydrochloric acid purification tank and the hydrochloric acid tank. The online hydrochloric acid analyzer and the level gauge are electrically connected to the control unit.

[0017] The B-line unit also includes a hydrochloric acid tank, and the liquid phase inlet of the hydrochloric acid tank is connected to the liquid phase outlet of the hydrochloric acid purification tank through a pipeline. Therefore, the purified hydrochloric acid solution will be directly transported to the hydrochloric acid tank for storage.

[0018] Optionally, the B-line unit further includes a first absorption tower and a second absorption tower connected by pipelines. A liquid pump is installed between the first absorption tower and the second absorption tower, and a liquid pump is installed between the first absorption tower and the first-stage water absorption tower. The gas phase inlet of the first absorption tower is connected to the gas phase outlet of the hydrochloric acid purification tank. Both the first absorption tower and the second absorption tower are filled with water. The second absorption tower is provided with a gas outlet.

[0019] The gas phase inlet of the first absorption tower is directly connected to the gas phase outlet of the hydrochloric acid purification tank to receive the stripping tail gas from the purification process. Both the first and second absorption towers are filled with water to absorb sulfur dioxide and hydrogen chloride gases in the stripping tail gas. The outlet of the second absorption tower is used to discharge the finally purified gas, preventing environmental pollution caused by the direct emission of acidic gases.

[0020] Optionally, the A-line unit further includes a bisulfite solution tank, the liquid phase inlet of which is connected to the liquid phase outlet of the bisulfite reaction tank, and an online bisulfite analyzer is installed between the bisulfite solution tank and the bisulfite reaction tank, the online bisulfite analyzer being electrically connected to the control unit.

[0021] These features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of this utility model will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this utility model. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the exhaust gas treatment device in this utility model.

[0023] The components include: 1. Primary water absorption tower; 2. Secondary water absorption tower; 3. Tertiary water absorption tower; 31. Online gas analyzer; 4. Quaternary water absorption tower; 5. Bisulfite reaction tank; 6. Bisulfite solution tank; 7. Hydrochloric acid purification tank; 71. Gas source; 72. Hydrochloric acid tank; 8. First absorption tower; 9. Second absorption tower. Detailed Implementation

[0024] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this utility model and should not be construed as limiting it.

[0025] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this patent. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0026] Example: like Figure 1 As shown, this embodiment provides a tail gas treatment device for the production of dichlorosulfonylimide, comprising: Unit A includes a primary water absorption tower 1, a secondary water absorption tower 2, a tertiary water absorption tower 3, a quaternary water absorption tower 4, and a bisulfite reaction tank 5. The gas phase outlet of the primary water absorption tower 1 is connected to the gas phase inlet of the secondary water absorption tower 2, the gas phase outlet of the secondary water absorption tower 2 is connected to the gas phase inlet of the tertiary water absorption tower 3, and the gas phase outlet of the tertiary water absorption tower 3 is connected to the gas phase inlet of the bisulfite reaction tank 5. The primary water absorption tower 1 is used to receive a mixture of hydrogen chloride and sulfur dioxide. The bisulfite reaction tank 5 is filled with an alkaline absorbent. Unit B includes a hydrochloric acid purification tank 7 connected to the liquid phase outlet of the primary water absorption tower 1 of Unit A.

[0027] In this embodiment, the primary water absorption tower 1 receives and preliminarily treats the raw mixed tail gas, generating crude hydrochloric acid and residual gas containing sulfur dioxide. Unit A includes interconnected primary water absorption tower 1, secondary water absorption tower 2, tertiary water absorption tower 3, and bisulfite reaction tank 5. The residual gas containing sulfur dioxide passes sequentially through secondary water absorption tower 2, tertiary water absorption tower 3, and bisulfite reaction tank 5. Bisulfite reaction tank 5 is filled with an alkaline absorbent to absorb sulfur dioxide and generate bisulfite. Unit B includes a hydrochloric acid purification tank 7 for receiving and purifying crude hydrochloric acid.

[0028] Specifically, to better separate the exhaust gas, the temperature inside the primary water absorption tower 1 is 30-60℃. At this temperature, the solubility of sulfur dioxide is low, and hydrogen chloride in the mixed gas is first largely absorbed by water, forming a crude hydrochloric acid solution. Most of the sulfur dioxide remains unabsorbed and enters other absorption towers in unit A with the gas flow. Therefore, preliminary separation of the two gases and enrichment of hydrogen chloride are achieved in the primary water absorption tower 1. The temperatures of the secondary water absorption tower 2 and the tertiary water absorption tower 3 are both 0-15℃. The low temperature reduces the volatility of hydrogen chloride. At this point, the mixed gas, rich in sulfur dioxide and containing a small amount of hydrogen chloride after treatment in the primary water absorption tower 1, is further absorbed by the secondary and tertiary water absorption towers 2 and 3. The remaining small amount of hydrogen chloride in the gas is further absorbed, resulting in high-purity sulfur dioxide gas being discharged from the top of the tertiary towers. Inside the bisulfite reaction tank 5, the high-purity sulfur dioxide gas reacts with the alkaline absorbent to generate a high-value bisulfite product. It should be noted that the temperatures of the secondary water absorption tower 2 and the tertiary water absorption tower 3 are set lower than those of the primary water absorption tower 1. This utilizes the principle that the solubility of all gases increases at low temperatures, ensuring that any remaining trace amounts of hydrogen chloride are completely captured by the low-temperature water in the secondary and tertiary water absorption towers 2 and 3. The remaining high-purity sulfur dioxide gas then enters the bisulfite reaction tank 5. While lowering the temperatures of the secondary and tertiary water absorption towers 2 and 3 allows for the absorption of a small amount of sulfur dioxide by the water, it ensures that the residual hydrogen chloride gas in the sulfur dioxide gas is completely captured, thus producing high-purity sulfur dioxide gas and laying the foundation for the subsequent high-quality bisulfite product.

[0029] In addition, the primary water absorption tower 1, the secondary water absorption tower 2, the tertiary water absorption tower 3, and the quaternary water absorption tower 4 can be filled with deionized water, softened water, tap water, or industrial clean water, etc.

[0030] The A-line unit also includes a control unit. Level gauges for monitoring the material level inside each of the primary water absorption tower 1, secondary water absorption tower 2, tertiary water absorption tower 3, quaternary water absorption tower 4, and bisulfite reaction tank 5 are installed. The level gauges are electrically connected to the control unit, and each absorption tower is equipped with a liquid pump.

[0031] In this embodiment, the gas phase inlet of the fourth-stage water absorption tower 4 is connected to the gas phase outlet of the third-stage water absorption tower 3, and the gas phase outlet of the fourth-stage water absorption tower 4 is connected to the bisulfite reaction tank 5. That is, the fourth-stage water absorption tower 4 is located after the third-stage tower and before the reaction tank in the gas path. Even if the purity of the gas exiting the gas phase outlet of the third-stage water absorption tower 3 is not good, the fourth-stage water absorption tower 4 can make up for it, ensuring that the purity of the sulfur dioxide gas entering the bisulfite reaction tank 5 is always high. It should be noted that the fourth-stage water absorption tower 4 is not always in use, but serves as a backup unit. Its use depends on the purity of the sulfur dioxide gas exiting the third-stage water absorption tower 3. That is, the fourth-stage tower is filled with low-temperature fresh water to perform a final water wash on the sulfur dioxide gas that does not meet the purity standard. Taking advantage of the fact that hydrogen chloride is very soluble in water at low temperatures, the residual hydrogen chloride impurities are deeply removed. The gas phase outlet of the fourth-stage water absorption tower 4 is connected to the bisulfite reaction tank 5. The gas phase outlet of the third-stage water absorption tower 3 is connected to the gas phase inlet of the fourth-stage water absorption tower 4 and the gas phase inlet of the bisulfite reaction tank 5 through pipelines, forming a switchable diversion path. The control unit switches the diversion path according to the detection results of the online gas analyzer 31, and directs the gas in the third-stage water absorption tower 3 to the fourth-stage water absorption tower 4 or the bisulfite reaction tank 5.

[0032] An online gas analyzer 31 is installed between the three-stage water absorption tower 3 and the four-stage water absorption tower 4, and the online gas analyzer 31 is electrically connected to the control unit. A first gas valve is installed at the gas phase inlet of the four-stage water absorption tower 4, and a second gas valve is installed between the three-stage water absorption tower 3 and the bisulfite reaction tank 5. Both the first and second gas valves are electrically connected to the control unit. The online gas analyzer 31 is used to detect the mass ratio of sulfur dioxide to hydrogen chloride in the gas output from the gas phase outlet of the three-stage water absorption tower 3. When the mass ratio is ≥100, the control unit closes the first gas valve; when the mass ratio is <100, the control unit opens the first gas valve.

[0033] In this embodiment, an online gas analyzer 31 is installed at the gas phase outlet of the three-stage water absorption tower 3 to monitor the mass ratio of sulfur dioxide to hydrogen chloride in the gas in real time. The online gas analyzer 31 and the control unit are connected by electrical signals to form a control structure from detection to execution. When the online gas analyzer 31 detects that the mass ratio is greater than or equal to 100, it indicates that the purity of the sulfur dioxide gas has met the standard. The control unit then closes the first gas valve controlling the opening and closing of the gas path of the four-stage water absorption tower 4 and opens the second gas valve directly connecting the three-stage water absorption tower 3 to the bisulfite reaction tank 5, allowing the qualified sulfur dioxide gas to directly enter the bisulfite reaction tank 5. Conversely, when the mass ratio is less than 100, it indicates that the purity of the sulfur dioxide gas is insufficient. The control unit opens the first gas valve controlling the opening and closing of the gas path of the four-stage water absorption tower 4 and the second gas valve directly connecting to the bisulfite reaction tank 5, forcing the gas to enter the four-stage water absorption tower 4 to remove residual hydrogen chloride, so as to ensure that only high-purity sulfur dioxide gas can ultimately enter the bisulfite reaction tank 5.

[0034] The solution fed from the liquid phase outlet of the primary water absorption tower 1 into the hydrochloric acid purification tank 7 has a hydrogen chloride content ≥30% and a sulfur dioxide content ≤1.5%.

[0035] In this embodiment, setting a target hydrogen chloride content of ≥30% ensures that the primary water absorption tower 1 produces crude hydrochloric acid with a sufficiently high concentration and purification value. Simultaneously, limiting the sulfur dioxide content to ≤1.5% reduces the contamination of sulfur dioxide into the hydrochloric acid product line, laying the foundation for obtaining high-purity hydrochloric acid through subsequent stripping. Therefore, by controlling the sulfur dioxide content in the crude hydrochloric acid entering the hydrochloric acid purification tank 7, the difficulty of subsequent purification is reduced, and high-purity hydrochloric acid with the required sulfur dioxide content can be obtained through stripping in the B-line unit. A detector is installed between the primary water absorption tower 1 and the hydrochloric acid purification tank 7 to detect whether the solution entering the hydrochloric acid purification tank 7 meets the standards.

[0036] The gas phase inlet of the hydrochloric acid purification tank 7 is connected to the gas source 71 to introduce compressed air into the hydrochloric acid purification tank 7 for stripping. A level gauge is used to monitor the material level in the tank, and the level gauge is electrically connected to the control unit.

[0037] In this embodiment, the gas phase inlet of the hydrochloric acid purification tank 7 is connected to the external gas source 71 through a pipeline. When the compressed air supplied by the gas source 71 is introduced into the crude hydrochloric acid solution in the hydrochloric acid purification tank 7, the sulfur dioxide dissolved in the solution will spontaneously pass through the gas-liquid interface due to its extremely high equilibrium partial pressure in the gas phase, diffuse from the liquid phase into the compressed air bubbles, and be carried away from the solution.

[0038] The B-line unit also includes a control unit and a hydrochloric acid tank 72 for storing finished hydrochloric acid. The liquid phase inlet of the hydrochloric acid tank 72 is connected to the liquid phase outlet of the hydrochloric acid purification tank 7 via a pipeline. The hydrochloric acid purification tank 7 is equipped with a level gauge for monitoring the material level inside the tank. An online hydrochloric acid analyzer is installed between the hydrochloric acid purification tank 7 and the hydrochloric acid tank 72. The online hydrochloric acid analyzer and the level gauge are electrically connected to the control unit.

[0039] In this embodiment, the B-line unit also includes a hydrochloric acid tank 72, and the liquid phase inlet of the hydrochloric acid tank 72 is connected to the liquid phase outlet of the hydrochloric acid purification tank 7 via a pipeline. Therefore, the purified hydrochloric acid solution is directly transported to the hydrochloric acid tank 72 for storage. By setting up the hydrochloric acid tank 72 and specifying the quality of the materials it receives (sulfur dioxide content ≤ 0.2%), the purity of the hydrochloric acid products shipped from the factory or sold externally can be guaranteed to be stable and reliable. A detector is also installed between the hydrochloric acid purification tank 7 and the hydrochloric acid tank 72 to detect whether the sulfur dioxide content in the hydrochloric acid entering the hydrochloric acid tank 72 meets the standard.

[0040] The B-line unit also includes a first absorption tower 8 and a second absorption tower 9 connected by pipelines. A liquid pump is installed between the first absorption tower 8 and the second absorption tower 9. A liquid pump is installed between the first absorption tower 8 and the first-stage water absorption tower 1. The gas phase inlet of the first absorption tower 8 is connected to the gas phase outlet of the hydrochloric acid purification tank 7. Both the first absorption tower 8 and the second absorption tower 9 are filled with water. The second absorption tower 9 is provided with a gas outlet.

[0041] In this embodiment, the gas phase inlet of the first absorption tower 8 is directly connected to the gas phase outlet of the hydrochloric acid purification tank 7 to receive the stripping tail gas from the purification process. Both the first absorption tower 8 and the second absorption tower 9 are filled with water to absorb sulfur dioxide and hydrochloric acid gas in the stripping tail gas. The temperature of the first absorption tower 8 is controlled at 0-15°C, and the gas outlet of the second absorption tower 9 is used to discharge the finally purified gas to prevent environmental pollution caused by the direct emission of acidic gases.

[0042] The A-line unit also includes a bisulfite solution tank 6, the liquid phase inlet of which is connected to the liquid phase outlet of the bisulfite reaction tank 5. An online bisulfite analyzer is installed between the bisulfite solution tank 6 and the bisulfite reaction tank 5, and the online bisulfite analyzer is electrically connected to the control unit.

[0043] In this embodiment, when high-purity sulfur dioxide gas comes into contact with an aqueous solution of an alkali metal hydroxide (such as sodium hydroxide) in the bisulfite reaction tank 5, a neutralization reaction occurs, generating an aqueous solution of bisulfite (such as sodium bisulfite). This aqueous solution is then transported to the bisulfite solution tank 6, achieving the storage and separation of byproducts. In other embodiments, the alkaline absorbent can also be ammonia or an aqueous solution of an alkali metal carbonate, etc. Both the bisulfite solution tank 6 and the bisulfite reaction tank 5 are equipped with detectors to check whether the bisulfite solution entering the bisulfite solution tank 6 meets the required standards.

[0044] Furthermore, the tail gas treatment device for the production of dichlorosulfonamide in this embodiment includes the following steps during use: S1, The mixed tail gas of hydrogen chloride and sulfur dioxide is passed into the first-stage water absorption tower 1 at a temperature of 30-60℃ to obtain crude hydrochloric acid and residual gas containing sulfur dioxide. S2, the remaining gas is passed into a secondary water absorption tower 2, a tertiary water absorption tower 3 and a selective quaternary water absorption tower 4 at a temperature of 0-15℃ to obtain purified sulfur dioxide gas. S3, the purified sulfur dioxide gas is passed into the bisulfite reaction tank 5 filled with alkaline absorbent to react and generate an aqueous solution of bisulfite. S4, when the content of hydrogen chloride in the crude hydrochloric acid in the primary water absorption tower 1 is ≥30% and the content of sulfur dioxide is ≤1.5%, the crude hydrochloric acid is transferred to the hydrochloric acid purification tank 7 for stripping. The stripping tail gas passes through the first absorption tower 8 and the second absorption tower 9 in sequence, and the temperature of the first absorption tower 8 is controlled at 0-15℃.

[0045] In this embodiment, step S1 utilizes a relatively high temperature of 30-60°C to create an environment that inhibits the dissolution of sulfur dioxide in the primary water absorption tower 1, achieving preliminary separation of the two gases. Step S2 utilizes a low temperature of 0-15°C in the secondary water absorption tower 2 and the tertiary water absorption tower 3 (and optionally the quaternary water absorption tower 4) to absorb part of the sulfur dioxide and deeply remove residual hydrogen chloride, achieving deep purification of the gas. Step S3 then uses a chemical neutralization reaction in the bisulfite reaction tank 5 to generate a bisulfite aqueous solution. Step S4 removes the crude hydrochloric acid for purification when the hydrogen chloride content is ≥30% and the sulfur dioxide content is ≤1.5%. Finally, the harmful mixed tail gas is converted into high-purity hydrochloric acid and bisulfite solutions, creating economic benefits.

[0046] Pipelines and liquid pumps are installed between the primary water absorption tower 1, the secondary water absorption tower 2, the tertiary water absorption tower 3, and the quaternary water absorption tower 4.

[0047] In this embodiment, when the primary water absorption tower 1 is emptied, the solution in the secondary water absorption tower 2 is transferred to the primary water absorption tower 1 via a liquid pump, the solution in the tertiary water absorption tower 3 is transferred to the secondary water absorption tower 2 via a liquid pump, and the solution in the quaternary water absorption tower 4 is transferred to the tertiary water absorption tower 3 via a liquid pump. This achieves continuous tail gas treatment and solves the problem of needing to shut down and replace the absorbent in a single absorption tower. When a certain absorption tower needs regeneration, the system can transfer liquid to ensure uninterrupted operation of the tail gas treatment process, improving equipment utilization and production efficiency.

[0048] In addition, when the primary water absorption tower 1 is emptied, the solution in the first absorption tower 8 can be transferred to the primary water absorption tower 1, and the solution in the second absorption tower 9 can be transferred to the first absorption tower 8.

[0049] Preparation Example 1: The mixed tail gas of hydrogen chloride and sulfur dioxide produced during the synthesis of dichlorosulfonylimide was fed into a primary water absorption tower 1, with the tower temperature controlled at 40°C. The gas output from the primary water absorption tower 1 was then sequentially fed into a secondary water absorption tower 2 and a tertiary water absorption tower 3, with the temperatures of both towers controlled at 15°C. The mass ratio of sulfur dioxide to hydrogen chloride in the gas phase outlet gas of the tertiary water absorption tower 3 was measured to be 92. This gas was then further fed into a quaternary water absorption tower 4, where the mass ratio increased to 101. This purified sulfur dioxide gas was then fed into a bisulfite reaction vessel 5 filled with 25% ammonia solution, with the reaction temperature controlled to not exceed 60°C, to prepare an ammonium bisulfite solution. When the pH of the ammonium bisulfite solution dropped to 3, it was transferred to a bisulfite solution vessel 6 to obtain an aqueous solution with an ammonium bisulfite content of 75.1%. When the solution output from the primary water absorption tower 1 contains 35.4% hydrogen chloride and 1.4% sulfur dioxide, the solution is transferred to the hydrochloric acid purification tank 7, and compressed air is introduced into the hydrochloric acid purification tank 7 for stripping. The hydrochloric acid obtained after stripping is transported to the hydrochloric acid tank 72 to obtain the finished hydrochloric acid, which contains 34.1% hydrogen chloride and 0.19% sulfur dioxide. The exhaust gas discharged from the hydrochloric acid purification tank 7 is sequentially passed into the first absorption tower 8 and the second absorption tower 9, which contain water, for absorption treatment. The temperature of the first absorption tower 8 is controlled at 15°C, ultimately achieving compliant exhaust gas emissions.

[0050] Preparation Example 2: The mixed tail gas of hydrogen chloride and sulfur dioxide produced during the synthesis of dichlorosulfonylimide was fed into a primary water absorption tower 1, with the tower temperature controlled at 50°C. The gas output from the primary water absorption tower 1 was then sequentially fed into a secondary water absorption tower 2 and a tertiary water absorption tower 3, with the temperatures of both towers controlled at 10°C. The mass ratio of sulfur dioxide to hydrogen chloride in the gas phase outlet gas of the tertiary water absorption tower 3 was measured to be 10:3. This purified sulfur dioxide gas was then passed into a bisulfite reaction vessel 5 filled with 25% ammonia solution, with the reaction temperature controlled to not exceed 60°C, to prepare an ammonium bisulfite solution. When the pH of the ammonium bisulfite solution dropped to 3, the solution was transferred to a bisulfite solution vessel 6 to obtain an aqueous solution with an ammonium bisulfite content of 74.6%. When the solution output from the primary water absorption tower 1 contains 34.6% hydrogen chloride and 1.2% sulfur dioxide, the solution is transferred to the hydrochloric acid purification tank 7, and compressed air is introduced into the hydrochloric acid purification tank 7 for stripping. The hydrochloric acid obtained after stripping is transported to the hydrochloric acid tank 72 to obtain the finished hydrochloric acid, which contains 33.5% hydrogen chloride and 0.15% sulfur dioxide. The exhaust gas discharged from the hydrochloric acid purification tank 7 is sequentially passed into the first absorption tower 8 and the second absorption tower 9, which contain water, for absorption treatment. The temperature of the first absorption tower 8 is controlled at 15°C, ultimately achieving compliant exhaust gas emissions.

[0051] Preparation Example 3: The mixed tail gas of hydrogen chloride and sulfur dioxide produced during the synthesis of dichlorosulfonylimide was fed into a primary water absorption tower 1, with the tower temperature controlled at 50°C. The gas output from the primary water absorption tower 1 was then sequentially fed into a secondary water absorption tower 2 and a tertiary water absorption tower 3, with the temperatures of both towers controlled at 10°C. The mass ratio of sulfur dioxide to hydrogen chloride in the gas phase outlet gas of the tertiary water absorption tower 3 was measured to be 10:4. This purified sulfur dioxide gas was then passed into a bisulfite reaction tank 5 filled with 25% ammonia solution, with the reaction temperature controlled to not exceed 60°C, to obtain a solution containing ammonium bisulfite. When the pH of the ammonium bisulfite solution reached 5, the solution was transferred to a bisulfite solution tank 6 to obtain an aqueous solution with an ammonium bisulfite content of 46.5% and an ammonium sulfite content of 15.2%. When the solution output from the primary water absorption tower 1 contains 34.8% hydrogen chloride and 1.3% sulfur dioxide, the solution is transferred to the hydrochloric acid purification tank 7, and compressed air is introduced into the hydrochloric acid purification tank 7 for stripping. The hydrochloric acid obtained after stripping is transported to the hydrochloric acid tank 72 to obtain the finished hydrochloric acid, which contains 33.6% hydrogen chloride and 0.16% sulfur dioxide. The exhaust gas discharged from the hydrochloric acid purification tank 7 is sequentially passed into the first absorption tower 8 and the second absorption tower 9, which contain water, for absorption treatment. The temperature of the first absorption tower 8 is controlled at 10℃, ultimately achieving compliant exhaust gas emissions.

[0052] Preparation Example 4: The mixed tail gas of hydrogen chloride and sulfur dioxide produced during the synthesis of dichlorosulfonylimide was fed into a primary water absorption tower 1, with the tower temperature controlled at 60°C. The gas output from the primary water absorption tower 1 was then sequentially fed into a secondary water absorption tower 2 and a tertiary water absorption tower 3, with the temperatures of both towers controlled at 5°C. The mass ratio of sulfur dioxide to hydrogen chloride in the gas phase outlet gas of the tertiary water absorption tower 3 was measured to be 1:10. This purified sulfur dioxide gas was then fed into a bisulfite reaction tank 5 filled with 25% ammonia solution, with the reaction temperature controlled not to exceed 60°C, to obtain a solution containing ammonium bisulfite. When the pH of the ammonium bisulfite solution reached 5.5, the solution was transferred to a bisulfite solution tank 6 to obtain an aqueous solution with an ammonium bisulfite content of 43.5% and an ammonium sulfite content of 17.8%. When the hydrogen chloride content in the solution output from the primary water absorption tower 1 is 34.2% and the sulfur dioxide content is 1.1%, the solution is transferred to the hydrochloric acid purification tank 7, and compressed air is introduced into the hydrochloric acid purification tank 7 for stripping treatment. The hydrochloric acid obtained after stripping is transported to the hydrochloric acid tank 72 to obtain the finished hydrochloric acid, which has a hydrogen chloride content of 33.1% and a sulfur dioxide content of 0.11%. The tail gas discharged from the hydrochloric acid purification tank 7 is sequentially passed into the first absorption tower 8 and the second absorption tower 9, which are filled with water, for absorption treatment. The temperature of the first absorption tower 8 is controlled at 5°C, ultimately achieving the goal of achieving compliant emissions of the tail gas.

[0053] Preparation Example 5: The mixed tail gas of hydrogen chloride and sulfur dioxide produced during the synthesis of dichlorosulfonylimide was fed into a primary water absorption tower 1, with the tower temperature controlled at 50°C. The gas output from the primary water absorption tower 1 was then sequentially fed into a secondary water absorption tower 2 and a tertiary water absorption tower 3, with the temperatures of both towers controlled at 10°C. The mass ratio of sulfur dioxide to hydrogen chloride in the gas phase outlet gas of the tertiary water absorption tower 3 was measured to be 10:3. This purified sulfur dioxide gas was then passed into a bisulfite reaction vessel 5 containing a 25% sodium hydroxide aqueous solution, with the reaction temperature controlled to not exceed 50°C, to obtain a sodium bisulfite-containing solution. When the pH of the sodium bisulfite-containing solution dropped to 4, the solution was transferred to a bisulfite solution vessel 6 to obtain an aqueous solution with a sodium bisulfite content of 46.1%. When the solution output from the primary water absorption tower 1 contains 34.6% hydrogen chloride and 1.4% sulfur dioxide, the solution is transferred to the hydrochloric acid purification tank 7, and compressed air is introduced into the hydrochloric acid purification tank 7 for stripping. The hydrochloric acid obtained after stripping is transported to the hydrochloric acid tank 72 to obtain the finished hydrochloric acid, which contains 33.7% hydrogen chloride and 0.17% sulfur dioxide. The exhaust gas discharged from the hydrochloric acid purification tank 7 is sequentially passed into the first absorption tower 8 and the second absorption tower 9, which contain water, for absorption treatment. The temperature of the first absorption tower 8 is controlled at 10℃, ultimately achieving compliant exhaust gas emissions.

[0054] Preparation Example 6: The mixed tail gas of hydrogen chloride and sulfur dioxide produced during the synthesis of dichlorosulfonylimide was fed into a primary water absorption tower 1, with the tower temperature controlled at 50°C. The gas output from the primary water absorption tower 1 was then sequentially fed into a secondary water absorption tower 2 and a tertiary water absorption tower 3, with the temperatures of both towers controlled at 10°C. The mass ratio of sulfur dioxide to hydrogen chloride in the gas phase outlet gas of the tertiary water absorption tower 3 was measured to be 10:5. This purified sulfur dioxide gas was then passed into a bisulfite reaction vessel 5 containing a 25% sodium hydroxide aqueous solution, with the reaction temperature controlled to not exceed 50°C, to obtain a sodium bisulfite-containing solution. When the pH of the sodium bisulfite-containing solution reached 7, the solution was transferred to a bisulfite solution vessel 6, yielding an aqueous solution with a sodium bisulfite content of 25.1% and a sodium sulfite content of 14.8%. When the solution output from the primary water absorption tower 1 contains 34.4% hydrogen chloride and 1.3% sulfur dioxide, the solution is transferred to the hydrochloric acid purification tank 7, and compressed air is introduced into the hydrochloric acid purification tank 7 for stripping. The hydrochloric acid obtained after stripping is transported to the hydrochloric acid tank 72 to obtain the finished hydrochloric acid, which contains 33.4% hydrogen chloride and 0.15% sulfur dioxide. The exhaust gas discharged from the hydrochloric acid purification tank 7 is sequentially passed into the first absorption tower 8 and the second absorption tower 9, which contain water, for absorption treatment. The temperature of the first absorption tower 8 is controlled at 10℃, ultimately achieving compliant exhaust gas emissions.

[0055] Based on the preparation examples 1 to 6, it can be seen that the finished hydrochloric acid produced by the exhaust gas treatment device of this invention has a hydrogen chloride content ≥32% and a sulfur dioxide content ≤0.2%, and the bisulfite aqueous solution obtained also has a high bisulfite content, which is economically beneficial.

[0056] The above are merely specific embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Those skilled in the art should understand that this utility model includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this utility model will be included within the scope of the claims.

Claims

1. A tail gas treatment device for the production of dichlorosulfonylimide, characterized in that, include: Unit A includes a primary water absorption tower, a secondary water absorption tower, a tertiary water absorption tower, a quaternary water absorption tower, and a bisulfite reaction tank. The gas phase outlet of the primary water absorption tower is connected to the gas phase inlet of the secondary water absorption tower, the gas phase outlet of the secondary water absorption tower is connected to the gas phase inlet of the tertiary water absorption tower, and the gas phase outlet of the tertiary water absorption tower is connected to the gas phase inlet of the bisulfite reaction tank. The primary water absorption tower is used to receive a mixture of hydrogen chloride and sulfur dioxide. The bisulfite reaction tank is filled with an alkaline absorbent. Line B includes a hydrochloric acid purification tank connected to the liquid phase outlet of the primary water absorption tower of Line A.

2. The tail gas treatment device for the production of dichlorosulfonylimide according to claim 1, characterized in that, The A-line unit also includes a control unit. The primary water absorption tower, the secondary water absorption tower, the tertiary water absorption tower, the quaternary water absorption tower, and the bisulfite reaction tank are all equipped with level gauges for monitoring the material level inside. The level gauges are electrically connected to the control unit, and each absorption tower is equipped with a liquid pump.

3. The tail gas treatment device for the production of dichlorosulfonylimide according to claim 1, characterized in that, The gas phase outlet of the fourth-stage water absorption tower is connected to the bisulfite reaction tank. The gas phase outlet of the third-stage water absorption tower is connected to the gas phase inlet of the fourth-stage water absorption tower and the gas phase inlet of the bisulfite reaction tank through pipelines, forming a switchable flow path. The control unit switches the flow path according to the detection results of the online gas analyzer, and directs the gas in the third-stage water absorption tower to the fourth-stage water absorption tower or the bisulfite reaction tank.

4. The tail gas treatment device for the production of dichlorosulfonylimide according to claim 2, characterized in that, An online gas analyzer is installed between the three-stage and four-stage water absorption towers, and the online gas analyzer is electrically connected to the control unit. A first gas valve is installed at the gas phase inlet of the four-stage water absorption tower, and a second gas valve is installed between the three-stage water absorption tower and the bisulfite reaction tank. Both the first and second gas valves are electrically connected to the control unit. The online gas analyzer is used to detect the mass ratio of sulfur dioxide to hydrogen chloride in the gas output from the gas phase outlet of the three-stage water absorption tower. When the mass ratio is ≥100, the control unit closes the first gas valve; when the mass ratio is <100, the control unit opens the first gas valve.

5. The tail gas treatment device for the production of dichlorosulfonylimide according to claim 1, characterized in that, The gas phase inlet of the hydrochloric acid purification tank is connected to a gas source, and compressed air is introduced into the hydrochloric acid purification tank for stripping. A level gauge is used to monitor the material level in the tank, and the level gauge is electrically connected to the control unit.

6. The tail gas treatment device for the production of dichlorosulfonylimide according to claim 1, characterized in that, The B-line unit also includes a control unit and a hydrochloric acid tank for storing finished hydrochloric acid. The liquid phase inlet of the hydrochloric acid tank is connected to the liquid phase outlet of the hydrochloric acid purification tank through a pipeline. The hydrochloric acid purification tank is equipped with a level gauge for monitoring the material level inside the tank. An online hydrochloric acid analyzer is installed between the hydrochloric acid purification tank and the hydrochloric acid tank. The online hydrochloric acid analyzer and the level gauge are electrically connected to the control unit.

7. The tail gas treatment apparatus for the production of dichlorosulfonylimide according to any one of claims 1-6, characterized in that, The B-line unit also includes a first absorption tower and a second absorption tower connected by pipelines. A liquid pump is installed between the first absorption tower and the second absorption tower, and a liquid pump is installed between the first absorption tower and the first-stage water absorption tower. The gas phase inlet of the first absorption tower is connected to the gas phase outlet of the hydrochloric acid purification tank. Both the first absorption tower and the second absorption tower are filled with water. The second absorption tower is provided with a gas outlet.

8. The tail gas treatment apparatus for the production of dichlorosulfonylimide according to any one of claims 1-6, characterized in that, The A-line unit also includes a bisulfite solution tank, the liquid phase inlet of which is connected to the liquid phase outlet of the bisulfite reaction tank, and an online bisulfite analyzer is installed between the bisulfite solution tank and the bisulfite reaction tank. The online bisulfite analyzer is electrically connected to the control unit.

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