Dimethyl sulfoxide rectification device and method
By optimizing the structural and operating parameters of the dimethyl sulfoxide distillation device, the problems of poor separation effect and high energy consumption of dimethyl sulfoxide crude product are solved, and high purity and stable dimethyl sulfoxide production are achieved.
Patent Information
- Application Number
- CN202510783143.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-12
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, dimethyl sulfoxide crude product has poor separation effect, unstable product quality, high maintenance cost, large energy consumption, and difficult to meet the needs of high purity and continuous production.
The device design is adopted that includes a distillation tower, a finished tower and a reboiler. By controlling pressure and temperature, combining the use of reflux and fixed discharge pipes, the material flow path is optimized, and a steam jacket is set to control feed and discharge, so as to achieve continuous separation and purification.
It improves the purity and yield of dimethyl sulfoxide, reduces the monowater content, meets electronic-grade standards, reduces maintenance frequency and energy consumption, and improves production efficiency.
Smart Images
Figure CN120437663A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of chemical industry, and in particular to a dimethyl sulfoxide distillation device and method. Background Art
[0002] The crude dimethyl sulfoxide synthesized by chemical companies contains impurities such as water and salt, and needs to be separated to obtain dimethyl sulfoxide products that meet purity requirements.
[0003] Currently, chemical companies use distillation towers to perform negative pressure distillation on crude dimethyl sulfoxide (DMSO) and collect the gas phase in a specific temperature range, which is then condensed to obtain the DMSO product. The distillation process presents the following problems: 1. The separation effect of crude dimethyl sulfoxide with complex components and high impurities is poor, which makes it difficult to meet the requirements of high-purity separation; 2. During the distillation process, as time goes by and the composition of the materials in the tower changes, it is difficult to maintain constant distillation conditions, resulting in large fluctuations in product quality and difficulty in ensuring product consistency and stability; 3. There are usually residues in the bottom product, which can easily lead to blockage of pipelines or feed ports. Regular cleaning and maintenance are required, which increases maintenance costs and downtime, affecting production continuity. 4. The distillation tower operates continuously, and heat and cooling need to be continuously provided to maintain the distillation process. The overall energy consumption is high, and the production cost also increases accordingly.
[0004] Therefore, designing a dimethyl sulfoxide distillation device with high operating efficiency and high separation purity is a problem that needs to be solved urgently by those skilled in the art. Summary of the Invention
[0005] One of the purposes of the present invention is to address the deficiencies of the prior art and provide a dimethyl sulfoxide distillation device with a simple structure and low modification cost, which can ensure the purity of the separated dimethyl sulfoxide product and improve the separation efficiency of the distillation device.
[0006] A second object of the present invention is to provide a method for separating and purifying dimethyl sulfoxide using the above-mentioned distillation device, which can continuously separate and obtain electronic grade dimethyl sulfoxide.
[0007] The technical solution for achieving one of the objectives of the present invention is: a dimethyl sulfoxide distillation device, comprising a distillation tower, a finished product tower, and a reboiler, wherein a feed pipe is provided in the middle of the side wall of the distillation tower, which is connected to a crude dimethyl sulfoxide source, a first gas phase pipe is provided at the top of the distillation tower, which is connected to a negative pressure source, a second gas phase pipe is provided at the top of the finished product tower, which is connected to the negative pressure source, a reflux pipe is provided at the top of the side wall of the finished product tower, which is connected to the reflux port of the distillation tower, the bottom of the side wall of the reboiler is connected to the bottom of the distillation tower and the finished product tower through a first pipeline and a second pipeline, respectively, the top of the side wall of the reboiler is connected to the middle of the side wall of the distillation tower and the finished product tower through a third pipeline and a fourth pipeline, respectively, the cross-sectional area of the fourth pipeline is larger than the cross-sectional area of the third pipeline, and a fixed row of pipes is provided at the bottom of the reboiler.
[0008] The feed pipe and the fixed row pipe are both provided with a steam jacket.
[0009] The downstream end of the reflux pipe is connected to a sprayer and is located in the distillation tower.
[0010] The bottoms of the distillation tower and the finished product tower are located at the same height, and the top of the finished product tower is lower than the top height of the distillation tower. The distillation tower is provided with a first reflux pipe and the finished product tower is provided with a second reflux pipe.
[0011] The first pipeline and the second pipeline both extend in a horizontal direction and are located at the same height.
[0012] The ratio of the cross-sectional area of the fourth pipeline to the cross-sectional area of the third pipeline is 1.5-2.5.
[0013] The third pipeline and the fourth pipeline have the same specifications, and the number of the third pipeline is one and the number of the fourth pipeline is two. The third pipeline and the fourth pipeline both extend in the horizontal direction and are located at the same height.
[0014] The technical solution for achieving the second object of the present invention is: a method for purifying dimethyl sulfoxide using any of the above-mentioned distillation devices, comprising the following steps: 1) Control the pressure in the distillation tower and the finished product tower to be less than -90Kpa; 2) Crude dimethyl sulfoxide is continuously fed to the distillation tower through the feed pipe, and the reboiler bottom temperature is controlled to be ≤155°C, the distillation tower top temperature to be ≤130°C, and the finished product tower top temperature to be ≤145°C; 3) Close the second gas phase pipe; 4) After the distillation system is stable, open the second gas phase pipe and control the flow rate of the reflux pipe to 0-100% of the feed pipe flow rate; 5) The gas phase discharged from the second gas phase pipe is condensed to obtain dimethyl sulfoxide product.
[0015] Furthermore, in step 2), the crude dimethyl sulfoxide is a mixture of dimethyl sulfoxide, dimethyl sulfone, water, sodium nitrate and sodium nitrite.
[0016] Preferably, in step 2), the temperature of the reboiler bottom is 145-155°C, preferably 152°C, the temperature of the top of the distillation tower is 100-135°C, preferably 120°C, and the temperature of the top of the finished product tower is 120-145°C, preferably 128°C.
[0017] The above technical solution has the following beneficial effects: 1. A dimethyl sulfoxide (DMSO) distillation apparatus comprises a distillation column, a finished product column, and a reboiler. A feed pipe is provided in the middle of the sidewall of the distillation column and is connected to a source of crude DMSO. Crude DMSO enters the distillation column through the feed pipe. A first gas phase pipe is provided at the top of the distillation column and is connected to a negative pressure source. Impurity water vapor and a small amount of DMSO formed by flash evaporation within the distillation column are discharged through the first gas phase pipe, completing water separation. A second gas phase pipe is provided at the top of the finished product column and is connected to a negative pressure source. Gas-phase DMSO formed by flash evaporation within the finished product column is discharged through the second gas phase pipe to produce finished DMSO. A reflux pipe is provided at the top of the sidewall of the finished product column and is connected to the reflux port of the distillation column. Gas-phase DMSO formed by flash evaporation within the finished product column passes through the reflux pipe, condenses, and then flows back into the distillation column. This effectively reduces DMSO loss during discharge from the distillation column, improves DMSO yield, and reduces the difficulty of handling the discharged impure water. The bottom of the sidewall of the reboiler is connected to the bottoms of the distillation tower and the finished product tower via a first pipeline and a second pipeline, respectively. That is, crude dimethyl sulfoxide entering the distillation tower enters the reboiler via the first pipeline, is heated to a boiling state, and forms a gaseous substance. The top of the sidewall of the reboiler is connected to the middle of the sidewalls of the distillation tower and the finished product tower via a third pipeline and a fourth pipeline, respectively. The cross-sectional area of the fourth pipeline is larger than the cross-sectional area of the third pipeline. The gaseous substance formed in the reboiler enters the distillation tower via the third pipeline and the finished product tower via the fourth pipeline, respectively. Moreover, the gaseous phase flow rate entering the finished product tower is large, while the gaseous phase flow rate entering the distillation tower is small. Under stable production conditions, the output of finished dimethyl sulfoxide can be increased, the reflux rate of the distillation tower can be increased, and the temperature regulation capacity of the distillation tower can be improved. The bottom of the reboiler is provided with a fixed discharge pipe for regularly discharging the heavy components remaining in the reboiler to achieve the purpose of continuous separation of dimethyl sulfoxide.
[0018] 2. Both the feed pipe and the fixed row pipe are equipped with steam jackets. The steam jacket installed on the feed pipe is used to increase the feed temperature and improve the flash evaporation effect of the impurity water in the crude dimethyl sulfoxide in the distillation tower; the steam jacket installed on the fixed row pipe is used to maintain the temperature. The heavy components remaining at the bottom of the reboiler are discharged through the fixed row pipe to prevent these heavy components from being blocked due to crystallization during the discharge process. In addition, the heat loss of the reboiler is reduced, ensuring the evaporation efficiency of the material in the reboiler.
[0019] 3. The bottoms of the distillation tower and the finished product tower are at the same height, and the top of the finished product tower is lower than the top of the distillation tower. Under the same vacuum degree, in the early stage of the device operation, the second gas phase pipe can be closed and the reflux pipe can be fully opened. The light components (mainly water) in the finished product tower can enter the distillation tower through the second gas phase pipe and be separated. The heavy components (dimethyl sulfoxide and trace amounts of dimethyl sulfoxide) in the finished product tower can be retained in the finished product tower, thereby improving the purity of the gas phase dimethyl sulfoxide in the finished product tower. When the distillation device is running stably, the second gas phase pipe can be opened and the opening of the reflux pipe can be adjusted to achieve the purpose of continuously producing dimethyl sulfoxide finished product.
[0020] 4. The purification method of the present invention controls the pressure in the distillation tower and the finished product tower to be less than -90KPa, the temperature of the reboiler bottom of the distillation tower to be ≤155°C, the temperature of the top of the distillation tower to be ≤130°C, and the temperature of the top of the finished product tower to be ≤145°C, so that the volatile gas phase in the crude dimethyl sulfoxide, water, dimethyl sulfoxide, and dimethyl sulfone form a mixed gas phase in the reboiler, a small part of which enters the distillation tower and most of which enters the finished product tower. The water vapor in the mixed gas phase entering the distillation tower almost remains in the gas phase and is separated through the first gas phase pipe. Most of the dimethyl sulfoxide and dimethyl sulfone are liquefied and enter the bottom liquid of the tower, and continue to enter the reboiler through the first pipeline. The mixed gas phase entering the finished product tower is first passed through The reflux line completely refluxes back into the distillation tower, where water vapor remains in the gas phase, while some dimethyl sulfoxide and dimethyl sulfone are liquefied and used as reflux liquid. This reduces the amount of dimethyl sulfoxide and dimethyl sulfone escaping from the distillation tower and ensures the dimethyl sulfoxide yield. Furthermore, as the device operates, because the top of the finished product tower is lower than the top of the distillation tower, more light components, such as water vapor, in the mixed gas phase in the finished product tower flow back through the reflux line to the distillation tower and are separated, while less heavy components, such as dimethyl sulfoxide and dimethyl sulfone, flow back through the reflux line to the distillation tower. This increases the purity of the target product in the finished product tower and improves the dimethyl sulfoxide purification capacity. Once the distillation system stabilizes, the second gas phase pipeline can be opened to discharge the mixed gas phase, resulting in a dimethyl sulfoxide product containing very little water and meeting electronic-grade dimethyl sulfoxide standards.
[0021] Industrial verification by the applicant has shown that the distillation and separation method of the present invention increases the production capacity of dimethyl sulfoxide by about 11% compared with the traditional double-tower distillation device, reduces the single-phase moisture content from an average of 270 ppm to 170 ppm, and increases the product purity from 99.99% to 99.999%, meeting the standards for electronic-grade dimethyl sulfoxide.
[0022] The following is a further description with reference to the accompanying drawings and specific implementations. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a connection diagram of the distillation device of the present invention.
[0024] In the accompanying drawings, 1 is a distillation tower, 2 is a finished product tower, 3 is a reboiler, 4 is a feed pipe, 5 is a first gas phase pipe, 6 is a second gas phase pipe, 7 is a reflux pipe, 8 is a fixed row pipe, 11 is a first pipeline, 12 is a second pipeline, 13 is a third pipeline, and 14 is a fourth pipeline. DETAILED DESCRIPTION Example
[0025] See also Figure 1 The dimethyl sulfoxide distillation device includes a distillation tower 1, a finished product tower 2, and a reboiler 3. Specifically, the distillation tower is provided with a first reflux pipe and the finished product tower is provided with a second reflux pipe. This is a conventional setting. The distillation tower 1 and the finished product tower 2 are located at the same height, and the top of the finished product tower 2 is lower than the top height of the distillation tower 1. The reboiler is located between the distillation tower and the finished product tower. A feed pipe 4 is provided in the middle of the side wall of the distillation tower 1, which is connected to the crude dimethyl sulfoxide source. In this embodiment, the feed pipe 4 is provided with a steam jacket. A first gas phase pipe 5 is provided at the top of the distillation tower 1, which is connected to the negative pressure source. Obviously, the first gas phase pipe passes through the condenser and is connected to the negative pressure source, which is common chemical knowledge. A second gas phase pipe 6 is provided at the top of the finished product tower 2, which is connected to the negative pressure source. Similarly, the second gas phase pipe passes through the condenser and is connected to the negative pressure source, which is common chemical knowledge. A reflux pipe 7 is provided at the top of the side wall of the finished product tower 2, which is connected to the reflux port of the distillation tower 1. The reflux pipe 7 is independent of the reflux pipes of the finished product tower and the distillation tower. The gaseous dimethyl sulfoxide generated in the finished product tower passes through the reflux pipe and is condensed into a liquid state before being refluxed to the distillation tower. In addition, a sprayer is connected to the downstream end of the reflux pipe 7, which is located in the distillation tower 1 and is in countercurrent contact with the gas phase generated in the distillation tower to reduce the content of dimethyl sulfoxide in the gas phase discharged from the distillation tower. The bottom of the side wall of the reboiler 3 is connected to the bottom of the distillation tower 1 and the finished product tower 2 respectively through a first pipeline 11 and a second pipeline 12. Specifically, the first pipeline 11 and the second pipeline 12 extend horizontally and are located at the same height. That is, the crude dimethyl sulfoxide entering the distillation tower is sent to the reboiler to be heated to a boiling state, and heats the liquid phase materials in the distillation tower and the finished product tower. The top of the side wall of the reboiler 3 is connected to the middle of the side wall of the distillation tower 1 and the finished product tower 2 through a third pipeline 13 and a fourth pipeline 14, respectively. The cross-sectional area of the fourth pipeline is larger than the cross-sectional area of the third pipeline. Usually, the third pipeline 13 and the fourth pipeline 14 are designed to have the same specifications, and the number of the third pipeline 13 is one and the number of the fourth pipeline 14 is two. Specifically, the third pipeline 13 and the fourth pipeline 14 both extend horizontally and are located at the same height. This allows the gaseous dimethyl sulfoxide generated by the reboiler to enter the finished product tower at a greater flow rate. The bottom of the reboiler 3 is provided with a fixed row of pipes 8, specifically, the fixed row of pipes 8 is provided with a steam jacket. Example
[0026] The method for purifying crude dimethyl sulfoxide using the distillation apparatus of Example 1 comprises the steps of: 1) Control the pressure in the distillation tower and the finished product tower to be less than -90Kpa. Generally, the lower the pressure, the lower the overall energy consumption; 2) Crude dimethyl sulfoxide is continuously fed to the distillation column through a feed pipe at a feed rate of 5500-6500 kg / h. The crude dimethyl sulfoxide composition is as follows: dimethyl sulfoxide content 80-90%, dimethyl sulfone 0.8-1.2%, water content 7-10%, and nitrate 4-8.7%. The reboiler bottom temperature is controlled at 152°C, the distillation column top temperature is 120°C, and the finished product column top temperature is controlled at 128°C. 3) Close the second gas phase pipe and fully open the reflux pipe to form full reflux; 4) After the distillation system stabilizes, open the second gas phase pipe and control the flow rate of the reflux pipe to 0 (after the second gas phase is opened, there is generally no flow here. When parameters such as moisture fluctuate, flow will only occur when internal sampling is used). Control the reflux flow rate of the distillation tower to 500-700 kg / h, and the reflux flow rate of the finished product tower to 400-600 kg / h; 5) The gas phase discharged from the second gas phase pipe is condensed to obtain a dimethyl sulfoxide product with a flow rate of 2500-3000 kg / h. According to the test of GB / T21395-2024 standard, the water content is 170 ppm, the dimethyl sulfoxide content is ≥99.999%, and the luminosity (Haizen) is 2.77. The gas phase discharged from the first gas phase pipe of the distillation tower is condensed and separately treated at a flow rate of 500-700 kg / h, with a dimethyl sulfoxide content of 90-95% and a water content of 4381 ppm. The flow rate of the reboiler bottom liquid is 2000-3000 kg / h.
[0027] Comparative Example 1 The third pipeline and the fourth pipeline are designed to have the same specifications and the same number, both of which are one. Other aspects are the same as in Example 1. The same batch of crude dimethyl sulfoxide is used as raw material, and the distillation parameters are controlled the same as in Example 2.
[0028] The gas phase discharged from the second gas phase pipe is condensed to obtain dimethyl sulfoxide product with a flow rate of 2252-2727 kg / h. According to the GB / T21395-2024 standard, the water content is 270 ppm and the dimethyl sulfoxide content is ≥99.99%.
[0029] Comparative Example 2 The heights of the distillation tower and the finished product tower were designed to be consistent. Other aspects were the same as in Example 1. The same batch of crude dimethyl sulfoxide was used as the raw material, and the distillation parameters were controlled the same as in Example 2.
[0030] The gas phase discharged from the second gas phase pipe is condensed to obtain a dimethyl sulfoxide product with a flow rate of 2880-3200 kg / h. According to the GB / T21395-2024 standard, the water content is 2330 ppm and the dimethyl sulfoxide content is 95-98%.
Claims
1. A dimethyl sulfoxide distillation device, characterized in that: It includes a distillation tower (1), a finished product tower (2), and a reboiler (3). A feed pipe (4) is provided in the middle of the side wall of the distillation tower (1), which is connected to a crude dimethyl sulfoxide source. A first gas phase pipe (5) is provided at the top of the distillation tower (1), which is connected to a negative pressure source. The top of the finished product tower (2) is provided with a second gas phase pipe (6) connected to the negative pressure source, and the top of the side wall of the finished product tower (2) is provided with a reflux pipe (7) connected to the reflux port of the distillation tower (1). The bottom of the side wall of the reboiler (3) is connected to the bottom of the distillation tower (1) and the bottom of the finished product tower (2) through the first pipeline (11) and the second pipeline (12), respectively. The top of the side wall of the reboiler (3) is connected to the middle of the side wall of the distillation tower (1) and the finished product tower (2) through the third pipeline (13) and the fourth pipeline (14), respectively. The cross-sectional area of the fourth pipeline is larger than the cross-sectional area of the third pipeline. A fixed row of pipes (8) is provided at the bottom of the reboiler (3).
2. The dimethyl sulfoxide distillation device according to claim 1, characterized in that: The feed pipe (4) and the fixed row pipe (8) are both provided with a steam jacket.
3. The dimethyl sulfoxide distillation device according to claim 1, characterized in that: The downstream end of the reflux pipe (7) is connected to a sprayer and is located in the distillation tower (1).
4. The dimethyl sulfoxide distillation device according to claim 1, characterized in that: The bottoms of the distillation tower (1) and the finished product tower (2) are located at the same height, and the top of the finished product tower (2) is lower than the top of the distillation tower (1). The distillation tower (1) is provided with a first reflux pipe, and the finished product tower (2) is provided with a second reflux pipe.
5. The dimethyl sulfoxide distillation device according to claim 1, characterized in that: The first pipeline (11) and the second pipeline (12) both extend in a horizontal direction and are located at the same height.
6. The dimethyl sulfoxide distillation device according to claim 1, characterized in that: The ratio of the cross-sectional area of the fourth pipeline to the cross-sectional area of the third pipeline is 1.5-2.
5.
7. The dimethyl sulfoxide distillation device according to claim 1 or 6, characterized in that: The third pipeline (13) and the fourth pipeline (14) have the same specifications, and the number of the third pipeline (13) is one, and the number of the fourth pipeline (14) is two. The third pipeline (13) and the fourth pipeline (14) both extend in the horizontal direction and are located at the same height.
8. A method for purifying dimethyl sulfoxide using any one of the distillation apparatuses according to claims 1 to 7, characterized in that: The following steps are involved: 1) Control the pressure in the distillation tower and the finished product tower to be less than -90Kpa; 2) Crude dimethyl sulfoxide is continuously fed to the distillation tower through the feed pipe, and the reboiler bottom temperature is controlled to be ≤155°C, the distillation tower top temperature to be ≤130°C, and the finished product tower top temperature to be ≤145°C; 3) Close the second gas phase pipe; 4) After the distillation system is stable, open the second gas phase pipe and control the flow rate of the reflux pipe to 0-100% of the feed pipe flow rate; 5) The gas phase discharged from the second gas phase pipe is condensed to obtain dimethyl sulfoxide product.
9. The method according to claim 8, characterized in that Step 2) The crude dimethyl sulfoxide is a mixture of dimethyl sulfoxide, dimethyl sulfone, water, sodium nitrate and sodium nitrite.
10. The method according to claim 8, characterized in that Step 2) The temperature of the reboiler bottom is 145-155°C, preferably 152°C, the temperature of the top of the distillation tower is 100-135°C, preferably 120°C, and the temperature of the top of the finished product tower is 120-145°C, preferably 128°C.