A process for preparing sodium sulfite using sodium bisulfite generated from sulfur-containing tail gas
By incinerating the sulfur-containing tail gas produced in dimethyl sulfoxide production and absorbing it with sodium hydroxide solution to form a sodium bisulfite solution, combined with ion exchange resin and sodium hydroxide solution, the high-purity anhydrous sodium sulfite was finally obtained through evaporation and centrifugal drying, solving the problems of sulfur-containing tail gas treatment and sodium sulfite preparation, and achieving efficient and economical product preparation.
Patent Information
- Application Number
- CN202411811222.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-10
- Publication Date
- 2025-04-08
AI Technical Summary
The sulfur-containing exhaust gases produced during the dimethyl sulfoxide production process are difficult to effectively treat, resulting in environmental pollution. At the same time, the prior art has not fully utilized these exhaust gases to prepare high-purity sodium sulfite.
The sodium bisulfite solution was formed by incineration of sulfur-containing tail gas and absorption with sodium hydroxide solution, followed by treatment by ion exchange resin and sodium hydroxide solution, and finally drying by evaporation and centrifugation to obtain high-purity anhydrous sodium sulfite.
The preparation of high purity (more than 90%) sodium sulfite is achieved, the problem of sulfur-containing exhaust gas treatment is solved, and economic benefits are increased. The product is high purity, easy to obtain raw materials, and simple operation process.
Smart Images
Figure SMS_1 
Figure SMS_2 
Figure SMS_3
Abstract
Description
Technical Field
[0001] The invention relates to a process for producing sodium sulfite by utilizing sulfur-containing tail gas, and in particular to a method for preparing sodium sulfite by utilizing sodium bisulfite generated by sulfur-containing tail gas. Background Art
[0002] In the production process of dimethyl sulfoxide, a large amount of sulfur-containing tail gas is generated, which pollutes the environment. Therefore, the treatment of sulfur-containing tail gas becomes a key problem to be solved in the production of dimethyl sulfoxide. The present invention utilizes the sulfur-containing waste gas in the factory to prepare sodium sulfite, which not only reduces environmental pollution but also realizes economic value.
[0003] Sodium sulfite is a common chemical raw material. There are various methods for producing sodium sulfite. The main methods for preparing anhydrous sodium sulfite include sulfur dioxide soda ash method, sulfur dioxide caustic soda method, sulfur dioxide sodium chloride method and Glauber's salt lime method. Most existing technologies focus on burning sulfur to produce high-purity sulfur dioxide, which is then further converted into sodium sulfite. The potential of preparing sodium sulfite by incinerating sulfur-containing tail gas has not been fully explored. Summary of the invention
[0004] In view of this, the purpose of the present invention is to provide a process for preparing sodium sulfite using sodium bisulfite generated from sulfur-containing tail gas, which not only solves the problem of sulfur-containing tail gas treatment in the existing dimethyl sulfoxide production, but also prepares sodium sulfite by-product to increase economic benefits.
[0005] In order to achieve the above object, the present invention is implemented in the following ways: The sulfur-containing tail gas (including sulfur-containing compounds such as methyl mercaptan, dimethyl sulfide, methanol, carbon disulfide and hydrogen sulfide) generated in the production process of dimethyl sulfoxide is incinerated and absorbed by sodium hydroxide solution to obtain a sodium bisulfite solution with a mass concentration of 15-40%. The 15%-40% sodium bisulfite solution is then discharged into the bottom of the desulfurization liquid intermediate tank through a pump, passes through the ion exchange resin area, and is maintained at a temperature of 40-60°C; The sodium bisulfite solution enters the neutralization kettle, and the liquid level is added to the half position of the neutralization kettle; 18%-50% sodium hydroxide solution is added through the pipeline to adjust the solution pH to 9.5-10.5. In this process, the sodium hydroxide solution needs to be added multiple times, and the pH change is constantly observed; then add 4-6 kg of activated carbon and stir for more than 30 minutes.
[0006] The neutralized solution is pumped through a plate and frame filter and a secondary filter to remove solid impurities such as activated carbon added to the neutralization kettle, thereby obtaining a clarified sodium sulfite solution with a mass concentration of 15-28%. The presence of a secondary filter is very necessary here to prevent leakage from the plate and frame filter.
[0007] The ion exchange resin is a mixture of any one or more of Amberlite HPR1100 Na, Amberlite HPR1200 Na, D113SC, Tulsimer® T-42, D201, CH-90 and CD552 resins.
[0008] The clarified liquid obtained by filtration directly enters two single-effect evaporators, and when the liquid level reaches 1 / 2-2 / 3 in the kettle, it is evaporated and concentrated under reduced pressure, and the amount of water evaporated is measured until the kettle contains 50%-65% of a solid-liquid mixture of sodium sulfite. The mixture is then discharged into a centrifuge for centrifugation and dried at 150°C to obtain anhydrous sodium sulfite with a mass concentration of more than 90%. The mother liquor from the centrifugation is returned to the neutralization kettle for reuse. At the same time, another set of two single-effect evaporators start working, evaporate and concentrate under reduced pressure, and dry by centrifugation. This cycle is repeated.
[0009] Beneficial effects: The present invention solves the problem of difficult treatment of sulfur-containing mixed tail gas in the production of dimethyl sulfoxide, and at the same time prepares a sodium sulfite product with a purity of more than 90%. The sulfur-containing tail gas is incinerated and absorbed by liquid alkali to generate a sodium bisulfite solution, eliminating the influence of carbon dioxide; an ion exchange resin is used to better remove iron ions in the absorption liquid under acidic conditions; then the sodium bisulfite solution is reacted with a sodium hydroxide solution to obtain a sodium sulfite solution, which is evaporated and concentrated in a single-effect evaporator, centrifugally dried, and the mother liquor is recycled to obtain an anhydrous sodium sulfite product with a purity higher than 90%. The raw materials of the invention are easy to obtain, the operation process is simple, and the product purity is high. DETAILED DESCRIPTION
[0010] The present invention is further described below in conjunction with embodiments, but the scope of protection claimed in the patent application of the present invention is not limited to the scope described in the embodiments.
[0011] Example 1 Sulfur-containing tail gas (including sulfur-containing compounds such as methyl mercaptan, dimethyl sulfide, methanol, carbon disulfide and hydrogen sulfide) is incinerated and absorbed by 18% sodium hydroxide solution to obtain a sodium bisulfite solution with a mass concentration of 17%, which is passed through the desulfurization liquid intermediate tank filled with Amberlite HPR1100 Na resin and maintained at a temperature of 40-60°C; then the sodium bisulfite solution enters the neutralization kettle, and 18% sodium hydroxide solution is added to adjust the pH to 9.5-10.5; 5 kg of activated carbon is added and stirred for more than 30 minutes; the neutralized liquid passes through a plate and frame filter and a secondary filter to remove solid impurities to obtain a clarified sodium sulfite solution with a mass concentration of 15%, which enters a single-effect evaporator and is evaporated under reduced pressure to concentrate to a 55% sodium sulfite solid-liquid mixture, which is centrifuged in a centrifuge and dried at 150°C to obtain anhydrous sodium sulfite, and the centrifuged mother liquor is returned to the neutralization kettle for reuse. The indicators of anhydrous sodium sulfite are as follows:
[0012] Example 2 Sulfur-containing tail gas (including sulfur-containing compounds such as methyl mercaptan, dimethyl sulfide, methanol, carbon disulfide and hydrogen sulfide) is incinerated and absorbed by 18% sodium hydroxide solution to obtain a sodium bisulfite solution with a mass concentration of 25%. It passes through a desulfurization liquid intermediate tank filled with Tulsimer® T-42 ion exchange resin and maintains a temperature of 40-60°C; then the sodium bisulfite solution enters the neutralization kettle, and 18% sodium hydroxide solution is added to adjust the pH to 9.5-10.5; 5 kg of activated carbon is added and stirred for more than 30 minutes; the neutralized liquid passes through a plate and frame filter and a secondary filter to remove solid impurities to obtain a clarified sodium sulfite solution with a mass concentration of 20%, which enters a single-effect evaporator and is evaporated under reduced pressure to concentrate to a 55% sodium sulfite solid-liquid mixture, which is centrifuged in a centrifuge and dried at 150°C to obtain anhydrous sodium sulfite. The centrifuged mother liquor is returned to the neutralization kettle for reuse. The indicators of anhydrous sodium sulfite are as follows:
[0013] Example 3 Sulfur-containing tail gas (including sulfur-containing compounds such as methyl mercaptan, dimethyl sulfide, methanol, carbon disulfide and hydrogen sulfide) is incinerated and absorbed by 18% sodium hydroxide solution to obtain a sodium bisulfite solution with a mass concentration of 34%. It passes through a desulfurization liquid intermediate tank equipped with D113SC and D201 mixed ion exchange resins and maintains a temperature of 40-60°C; then the sodium bisulfite solution enters the neutralization kettle, and 18% sodium hydroxide solution is added to adjust the pH to 9.5-10.5; 5 kg of activated carbon is added and stirred for more than 30 minutes; the neutralization liquid passes through a plate and frame filter and a secondary filter to remove solid impurities to obtain a clarified sodium sulfite solution with a mass concentration of 25%, which enters a single-effect evaporator to be evaporated under reduced pressure and concentrated to a 55% sodium sulfite solid-liquid mixture, which is centrifuged in a centrifuge and dried at 150°C to obtain anhydrous sodium sulfite. The centrifuged mother liquor is returned to the neutralization kettle for reuse. The indicators of anhydrous sodium sulfite are as follows:
[0014] Example 4 Sulfur-containing tail gas (including sulfur-containing compounds such as methyl mercaptan, dimethyl sulfide, methanol, carbon disulfide and hydrogen sulfide) is incinerated and absorbed by 18% sodium hydroxide solution to obtain a sodium bisulfite solution with a mass concentration of 33%. It passes through the desulfurization liquid intermediate tank equipped with CD552 ion exchange resin and maintains the temperature at 40-60°C; then the sodium bisulfite solution enters the neutralization kettle, and 50% sodium hydroxide solution is added to adjust the pH to 9.5-10.5; 5 kg of activated carbon is added and stirred for more than 30 minutes; the neutralization liquid passes through a plate and frame filter and a secondary filter to remove solid impurities to obtain a clarified sodium sulfite solution with a mass concentration of 27%, which enters a single-effect evaporator and is evaporated under reduced pressure to concentrate to a 55% sodium sulfite solid-liquid mixture, which is centrifuged in a centrifuge and dried at 150°C to obtain anhydrous sodium sulfite. The centrifuged mother liquor is returned to the neutralization kettle for reuse. The indicators of anhydrous sodium sulfite are as follows: .
Claims
1. A process for preparing sodium sulfite using a sodium bisulfite solution generated from sulfur-containing tail gas, characterized in that: The steps include: (1) The sulfur-containing tail gas generated in the production process of dimethyl sulfoxide is incinerated and absorbed by sodium hydroxide solution to obtain sodium bisulfite solution; (2) A sodium bisulfite solution with a mass concentration of 15-40% is introduced from the bottom into the desulfurization liquid intermediate tank to remove iron ions. The middle area of the desulfurization liquid intermediate tank is filled with ion exchange resin and maintained at a temperature of 40-60°C; (3) adding sodium hydroxide solution to the sodium bisulfite solution after the iron removal treatment to carry out a neutralization reaction, adding activated carbon to the reaction solution after the neutralization reaction, and stirring to obtain a sodium sulfite solution; (4) The sodium sulfite solution obtained in step (3) is filtered, evaporated, concentrated, centrifuged, and dried to obtain anhydrous sodium sulfite.
2. The process for preparing sodium sulfite by utilizing sodium bisulfite solution generated by sulfur-containing tail gas according to claim 1, characterized in that: In step (1), the sodium hydroxide solution is absorbed into a sodium bisulfite solution with a mass concentration of 15-40%, preferably, the sodium bisulfite solution has a concentration of 25-36%.
3. The process for preparing sodium sulfite by utilizing sodium bisulfite solution generated by sulfur-containing tail gas according to claim 1, characterized in that: In step (2), the ion exchange resin is a mixture of any one or more of Amberlite HPR1100 Na, Amberlite HPR1200 Na, D113SC, Tulsimer® T-42, D201, CH-90 and CD552 resins.
4. The process for preparing sodium sulfite by utilizing sodium bisulfite solution generated by sulfur-containing tail gas according to claim 1, characterized in that: In step (3), the mass concentration of the sodium hydroxide solution is 18%-50%, the pH is adjusted to 9.5-10.5, and the temperature is in the range of 60-100°C. It is particularly preferred that the pH is 10.5 and the temperature is in the range of 80-85°C.
5. The process for preparing sodium sulfite by utilizing sodium bisulfite solution generated by sulfur-containing tail gas according to claim 1, characterized in that: In step (4), the solution is evaporated and concentrated until the mass concentration of the solution reaches 50%-65%; the drying temperature is 145-150°C.