A demister and rectifying column facilitating purification of 3-methylthiopropanal

Abstract

The utility model provides a kind of demister and rectifying column facilitating 3-methylthiopropionaldehyde purification, it solves the technical problem that the existing 3-methylthiopropionaldehyde rectification temperature is too high, time is too long, causes to occur side reaction;Rectifying column includes tower body, tower body includes demister, demister is equipped with tank body, according to gas flow direction, baffle plate demister, silk screen demister are installed in tank body and are spaced, the air inlet of tank body is connected with baffle, and gas outlet is connected with MMP gas discharge pipe;Demister is equipped with first gas phase discharge demister, second gas phase discharge demister, first gas phase discharge demister is installed between first falling-film evaporator and second falling-film evaporator, and the MMP gas discharge pipe of first gas phase discharge demister is communicated with first MMP gas discharge port;Second gas phase discharge demister is installed in tower kettle, and the MMP gas discharge pipe of second gas phase discharge demister is communicated with second MMP gas discharge port;It can be widely applied in rectifying column technical field.

Description

Technical Field

[0001] This application relates to the field of distillation column technology, and in particular to a demister and distillation column for facilitating the purification of 3-methylthiopropionaldehyde. Background Technology

[0002] 3-Methylthiopropionaldehyde (MMP) is an important organic compound, usually a colorless to pale yellow liquid with a characteristic odor. It has wide applications in feed, food, and pharmaceutical industries. In the feed industry, MMP is a key intermediate in the synthesis of methionine, an essential amino acid that can significantly improve animal growth performance and feed conversion rate. In the food industry, MMP is used to formulate flavorings, giving food a unique taste. In the pharmaceutical industry, MMP is used as a pharmaceutical intermediate and an organic synthesis intermediate, participating in various chemical reactions.

[0003] In the production process, the purification of MMP is crucial. Distillation columns are commonly used purification equipment, utilizing the difference in volatility between MMP and other components to separate them from the mixture through multiple partial vaporization and condensation processes. Currently, the conventional MMP distillation process employs a series connection of light component removal columns and heavy component removal columns. The mixture containing MMP passes through these columns sequentially to remove the light and heavy components, respectively, yielding a high-purity MMP product. However, because MMP is a heat-sensitive material, the distillation purification process in the light and heavy component removal columns involves temperatures of 105–120°C and residence times of 5–30 minutes. These high temperatures and excessively long residence times can lead to side reactions in MMP, reducing the MMP product yield. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the above-mentioned technologies and provide a demister and distillation column for the purification of 3-methylthiopropionaldehyde, thereby shortening the residence time of MMP in the distillation process, reducing the generation of side reactions, and improving the yield of MMP products.

[0005] Therefore, this utility model provides a demister for easy purification of 3-methylthiopropionaldehyde. The demister is equipped with a tank. According to the gas flow direction, baffle demisters and wire mesh demisters are installed at intervals inside the tank. A baffle is connected to the air inlet of the tank, and an MMP gas outlet pipe is connected to the air outlet of the tank.

[0006] Preferably, the angle between the baffle and the plane where the air inlet of the tank is located is 45° to 65°.

[0007] Preferably, the projected area of ​​the baffle plate on the plane where the air inlet of the tank is located accounts for 1 / 2 to 2 / 3 of the area of ​​the plane where the air inlet of the tank is located.

[0008] Preferably, the distance between the baffle demister and the wire mesh demister is controlled at 100-150 mm.

[0009] Preferably, the surface roughness Ra of the baffle plate in the baffle demister is ≤0.8μm.

[0010] Preferably, the wire mesh demister has a porosity >97%, a pressure drop of 0.2–0.5 kPa, a wire diameter of 0.2 mm–0.25 mm, and a specific surface area controlled at 200–300 m². 2 / m 3 .

[0011] Preferably, both the baffle demister and the wire mesh demister are made of austenitic stainless steel.

[0012] This utility model also provides a distillation column for the purification of 3-methylthiopropionaldehyde. The distillation column includes a column body, which includes an upper column top, a rectification section, a stripping section, a falling film evaporator, and a column bottom connected in sequence from top to bottom.

[0013] The top of the upper tower is connected to a light component discharge port.

[0014] The rectification section is equipped with the first packing material.

[0015] A top distributor is installed between the top of the column and the rectification section, and the top distributor is connected to a reflux feed inlet.

[0016] A second packing material is installed in the stripping section.

[0017] A feed distributor is installed between the stripping section and the rectification section, and the feed distributor is connected to an MMP crude product inlet.

[0018] The first falling film evaporator is connected to a first steam inlet and a first steam condensate outlet.

[0019] The second falling film evaporator is connected to a second steam inlet and a second steam condensate outlet.

[0020] The bottom of the tower is connected to a discharge port for waste material.

[0021] The falling film evaporator includes a first falling film evaporator and a second falling film evaporator. The first falling film evaporator is spaced above the second falling film evaporator. The first falling film evaporator is connected to a first steam inlet and a first steam condensate outlet. The second falling film evaporator is connected to a second steam inlet and a second steam condensate outlet.

[0022] The tower body also includes a demister, which has a tank. According to the gas flow direction, baffle demisters and wire mesh demisters are installed at intervals inside the tank. A baffle is connected to the air inlet of the tank, and an MMP gas outlet pipe is connected to the air outlet of the tank.

[0023] The demister is equipped with a first gas phase discharge demister and a second gas phase discharge demister.

[0024] The first gas phase discharge demister is installed between the first falling film evaporator and the second falling film evaporator, and the MMP gas discharge pipe of the first gas phase discharge demister is connected to the first MMP gas discharge port.

[0025] The second gas phase discharge demister is installed inside the tower, and the MMP gas discharge pipe of the second gas phase discharge demister is connected to the second MMP gas discharge port.

[0026] Preferably, both the first packing and the second packing are wire mesh corrugated structured packing.

[0027] Preferably, the angle between the baffle and the plane where the air inlet of the tank is located is 45° to 65°.

[0028] Preferably, the projected area of ​​the baffle plate on the plane where the air inlet of the tank is located accounts for 1 / 2 to 2 / 3 of the area of ​​the plane where the air inlet of the tank is located.

[0029] Preferably, the distance between the baffle demister and the wire mesh demister is controlled at 100-150 mm.

[0030] Preferably, the surface roughness Ra of the baffle plate in the baffle demister is ≤0.8μm.

[0031] Preferably, the wire mesh demister has a porosity >97%, a pressure drop of 0.2–0.5 kPa, a wire diameter of 0.2 mm–0.25 mm, and a specific surface area controlled at 200–300 m². 2 / m 3 .

[0032] Preferably, both the baffle demister and the wire mesh demister are made of austenitic stainless steel.

[0033] The beneficial effects of this utility model are as follows: This utility model provides a demister and distillation column for easy purification of 3-methylthiopropionaldehyde. By coupling the distillation column with a falling film evaporator, the purification temperature of MMP is reduced, and the rapid separation of MMP from heavy components is achieved. This fundamentally solves the problem of excessively high MMP distillation temperature and excessively long residence time in the prior art, which leads to side reactions and reduces the yield of MMP products. This shortens the residence time of MMP in the distillation process, reduces the generation of side reactions, and ultimately improves the yield of MMP products. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the distillation column of this utility model; Figure 2 This is a schematic diagram of the structure of the demister of this utility model; Figure 3 for Figure 2 The diagram shows a partial cross-sectional view of the structure, with arrows indicating the direction of gas flow.

[0036] The diagram is labeled as follows: 1. Top of column; 2. Rectifying section; 3. Stripping section; 4. First falling film evaporator; 5. Second falling film evaporator; 6. Reboiler; 7. Light component outlet; 8. Top distributor; 9. Reflux feed inlet; 10. Feed distributor; 11. MMP crude product feed inlet; 12. By-product outlet; 13. Demister; 14. First MMP gas outlet; 15. Second MMP gas outlet; 21. First packing; 31. Second packing; 41. First steam feed inlet; 42. First steam condensate outlet; 51. Second steam feed inlet; 52. Second steam condensate outlet; 131. First vapor phase outlet demister; 132. Second vapor phase outlet demister; 133. Tank; 134. Baffle demister; 135. Wire mesh demister; 136. 137. Baffle plate; 138. MMP gas outlet pipe; 139. Open channel; α. The angle between the plane containing the baffle plate 136 and the air inlet of the tank body 133; d. The distance between the baffle plate demister 134 and the wire mesh demister 135. Detailed Implementation

[0037] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application. Unless otherwise specified, the methods used in this utility model are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.

[0038] Depend on Figure 1As shown, this utility model provides a distillation column for easy purification of 3-methylthiopropionaldehyde. The distillation column includes a column body, which includes an upper column top 1, a rectification section 2, a stripping section 3, a falling film evaporator, and a column bottom 6 connected sequentially from top to bottom.

[0039] The top of the upper tower 1 is connected to a light component discharge port 7.

[0040] The rectification section 2 is equipped with a first packing material 21.

[0041] A top distributor 8 is installed between the top of the column 1 and the rectification section 2, and the top distributor 8 is connected to a reflux feed inlet 9.

[0042] The stripping section 3 is equipped with a second packing material 31.

[0043] A feed distributor 10 is installed between the stripping section 3 and the rectification section 2, and the feed distributor 10 is connected to an MMP crude product inlet 11.

[0044] The first falling film evaporator 4 is connected to a first steam inlet 41 and a first steam condensate outlet 42.

[0045] The second falling film evaporator 5 is connected to a second steam inlet 51 and a second steam condensate outlet 52.

[0046] The bottom of the tower 6 is connected to a foot material discharge port 12.

[0047] The falling film evaporator is provided with a first falling film evaporator 4 and a second falling film evaporator 5. The first falling film evaporator 4 is spaced above the second falling film evaporator 5. The first falling film evaporator 4 is connected to a first steam inlet 41 and a first steam condensate outlet 42. The second falling film evaporator 5 is connected to a second steam inlet 51 and a second steam condensate outlet 52.

[0048] The tower body also includes a demister 13, which has a tank 133. According to the gas flow direction, baffle demisters 134 and wire mesh demisters 135 are installed at intervals inside the tank 133. A baffle 136 is connected to the air inlet of the tank 133, and an MMP gas outlet pipe 137 is connected to the air outlet of the tank 133.

[0049] The demister 13 is equipped with a first gas phase discharge demister 131 and a second gas phase discharge demister 132.

[0050] The first gas phase discharge demister 131 is installed between the first falling film evaporator 4 and the second falling film evaporator 5, and the MMP gas discharge pipe 137 of the first gas phase discharge demister 131 is connected to the first MMP gas discharge port 14.

[0051] The second gas phase discharge demister 132 is installed inside the tower 6, and the MMP gas discharge pipe 137 of the second gas phase discharge demister 132 is connected to the second MMP gas discharge port 15.

[0052] The working process of this utility model is as follows: [The process is described in the original text.] Figure 1 As shown, crude MMP liquid enters the distillation column through crude MMP inlet 11 and is evenly distributed on the second packing 31 of the stripping section 3 via feed distributor 10. The temperature is controlled at 65-70℃ and the pressure is controlled at 2.0-2.5 kPa(A). Utilizing the principles of gas-liquid phase equilibrium, heat transfer, and mass exchange, the purity of the feed product is improved. Specifically, within the second packing 31, the light components (including methanethiol, water, methanol, and a small amount of MMP, etc.) in the feed crude MMP liquid are converted into gaseous components and volatilized upwards. The remaining feed crude MMP liquid mainly consists of liquid containing heavy components, which falls under its own gravity. After vaporization in stripping section 3, the light component passes upward through the first packing 21 in rectification section 2 and exits through the top of the column 1, where the temperature is 30–40°C and the pressure is 0.8–1.1 kPa(A). Then, the light component enters the external top condenser through the light component outlet 7 for condensation to 10–20°C, before entering the receiving tank of the external top condenser. Next, the condensed material is divided into two parts: top distillate and top reflux. The top distillate is sent as the top fraction to the external light component buffer tank, and finally enters the light component... Waste liquid tank; The reflux liquid at the top of the column is refluxed through the reflux inlet 9 and evenly distributed on the first packing 21 of the rectification section 2 through the top distributor 8. It enters the first packing 21 and fully contacts and mixes with the light components that rise into the first packing 21 after vaporization in the stripping section 3. The temperature is 55-65℃, the pressure is 1.4-2.0KPa(A), and the reflux ratio is 1-5. The light components are separated, so that the light components gradually accumulate at the top of the column 1 after vaporization, while the liquid containing heavy components gradually accumulates under its own gravity and falls onto the second packing 31 of the stripping section 3.

[0053] In the stripping section 3, the liquid containing heavy components falls into the first falling film evaporator 4, where most of the MMP in the liquid evaporates and vaporizes through heat transfer, and the liquid is concentrated. Steam is supplied to the first falling film evaporator 4 through the first steam inlet 41, and the condensate from the steam in the first falling film evaporator 4 is discharged to the external condensate recovery system through the first steam condensate outlet 42, which heats and concentrates the liquid in the first falling film evaporator 4. Among them, the vaporized MMP (purity of about 99.3%, recovery rate of about 90%) is discharged from the bottom of the first falling film evaporator 4 and enters the first gas phase discharge demister 131. By adjusting the steam feed rate, the temperature of the vaporized MMP is controlled at 75-85°C and the pressure at 1.2-1.5 kPa(A). The concentrated liquid (including MMP polymer, acrolein polymer, and a small portion of MMP, etc.) is discharged from the drain outlet at the bottom of the first falling film evaporator 4 and falls into the second falling film evaporator 5.

[0054] Depend on Figures 1-3 As shown, the MMP vaporized and discharged from the first falling film evaporator 4 enters the first gas phase discharge demister 131 through the opening channel 138 between the baffle plate 136 and the air inlet of the tank 133. It first passes through the baffle plate demister 134 to remove larger droplets entrained in the vaporized MMP, and then through the wire mesh demister 135 to remove smaller droplets. The combined use of the baffle plate demister 134 and the wire mesh demister 135 achieves efficient gas-liquid separation and improves the purity of the vaporized MMP. Then, it enters the external MMA condenser through the MMP gas discharge pipe 137 and the first MMP gas discharge port 14, where it is condensed to 0°C. The condensed MMP is then stored in the external MMA finished product tank. A small amount of non-condensable gases (including oxygen, nitrogen, carbon dioxide, and sulfur-containing waste gas from decomposition) are incinerated, ensuring compliance with environmental emission requirements. The function of the baffle plate 136 is to block large particles or viscous polymers entrained in the vaporized MMP, and to prevent large particles and viscous substances from being carried by the airflow through the opening channel 138 to the lower surface of the baffle plate demister 134, which would increase the resistance at the outlet of the tank 133, or even cause the vaporized MMP to be unable to pass through the first gas phase discharge demister 131.

[0055] Depend on Figure 1As shown, the concentrated liquid discharged from the bottom of the first falling film evaporator 4 falls into the second falling film evaporator 5, where residual MMP in the liquid evaporates and vaporizes through heat transfer, further concentrating the liquid. Steam is supplied to the second falling film evaporator 5 through the second steam inlet 51, and the condensate from the steam inlet 5 is discharged to the external condensate recovery system through the second steam condensate outlet 52, completing the further concentration of the concentrated liquid in the second falling film evaporator 5 by heating and evaporation. The vaporized MMP (purity of 80-85%) is discharged from the bottom of the second falling film evaporator 5 into the reboiler 6. By adjusting the steam feed rate, the temperature of the vaporized MMP is controlled at 85-100℃ and the pressure at 1-2 kPa(A). The further concentrated liquid is discharged from the drain outlet at the bottom of the second falling film evaporator 5 and falls into the reboiler 6.

[0056] Depend on Figures 1-3 As shown, the MMP vaporized and discharged from the second falling film evaporator 5 enters the second gas phase discharge demister 132 (which has the same structure and function as the first gas phase discharge demister 131, and will not be described again). Then, it enters another external MMA condenser through the second MMP gas outlet 15. After condensing to 0°C, the condensed MMP is mixed with the crude MMP liquid that needs to be purified and enters the distillation column through the crude MMP inlet 11 for distillation purification. A small amount of non-condensable gases (including oxygen, nitrogen, carbon dioxide, and sulfur-containing waste gas from decomposition) are incinerated, ensuring compliance with environmental emission requirements.

[0057] Depend on Figure 1 As shown, the further concentrated liquid (i.e. waste material, which includes MMP polymer, acrolein polymer, a small amount of MMP with a purity of about 1%) discharged from the bottom of the second falling film evaporator 5 falls into the bottom of the tower 6 and is discharged to the external waste liquid treatment system from the waste material outlet 12.

[0058] In some embodiments, preferably, by Figure 1 As shown, both the first packing 21 and the second packing 31 are wire mesh corrugated structured packings. The metal wire mesh is corrugated, which effectively increases the specific surface area of ​​the packing and has a strong capillary effect, making it particularly suitable for vacuum distillation of heat-sensitive materials such as MMP.

[0059] In some embodiments, preferably, by Figure 3 As shown, the angle α between the baffle 136 and the plane where the air inlet of the tank 133 is located is 45° to 65°, and the baffle 136 is effective in blocking large particles or viscous polymers entrained in the MMP gas.

[0060] In some embodiments, preferably, by Figure 3As shown, the projected area of ​​the baffle 136 on the plane where the air inlet of the tank 133 is located accounts for 1 / 2 to 2 / 3 of the area of ​​the plane where the air inlet of the tank 133 is located. The baffle 136 has a good technical effect in blocking large particles or viscous polymers entrained in MMP gas.

[0061] In some embodiments, preferably, by Figure 3 As shown, the distance d between the baffle demister 134 and the wire mesh demister 135 is controlled at 100-150mm to ensure that the small amount of liquid entrained in the MMP gas can be completely separated, so that the quality of the MMA product can be further guaranteed.

[0062] In some embodiments, preferably, by Figure 3 As shown, the surface roughness Ra of the baffle plate of the baffle plate demister 134 is ≤0.8μm. The surface of the baffle plate is treated by external polishing technology to reduce the surface roughness, reduce the micro-unevenness of the surface, make the surface smoother, improve the defoaming efficiency, reduce gas resistance, and make it easier for the liquid to form droplets and detach from the surface.

[0063] In some embodiments, preferably, by Figure 3 As shown, the porosity of the wire mesh demister 135 is >97%, the pressure drop is 0.2–0.5 kPa, the wire diameter is 0.2–0.25 mm, and the specific surface area is controlled at 200–300 m². 2 / m 3 It has advantages such as high porosity and low pressure drop, small wire diameter, large specific surface area, efficient gas-liquid separation, and reduced energy consumption.

[0064] In some embodiments, preferably, by Figure 3 As shown, both the baffle demister 134 and the wire mesh demister 135 are made of austenitic stainless steel. For example, austenitic stainless steel grades such as 304, 304L, 316, and 316L. Because this material contains molybdenum, it has excellent resistance to pitting and corrosion from sulfur compounds. In addition, this material also has advantages such as good plasticity and toughness, non-magnetic properties, good weldability, and high strength.

[0065] This invention provides a demister and distillation column for the purification of 3-methylthiopropionaldehyde. By coupling the distillation column with a falling film evaporator, during the entire process from the liquid containing heavy components entering the first falling film evaporator 4 to the vaporization and discharge of MMP in the second falling film evaporator 5, which then enters the second gas-phase discharge demister 132, the following measures are taken: First, the MMP purification temperature is reduced. The first falling film evaporator 4 controls the temperature of the vaporized MMP to 75–85°C, and the second falling film evaporator 5 controls the temperature to 85–100°C. Second, the MMP residence time is shortened. The first and second gas-phase discharge demisters 131 and 132 enable rapid separation of the heat-sensitive material MMP from the heavy components, reducing the residence time of the entire process to 20–60 seconds. This fundamentally solves the technical problems of excessively high MMP distillation temperature and excessively long residence time in existing technologies, which lead to side reactions and reduced MMP product yield, ultimately improving the MMP product yield.

[0066] In the description of this utility model, it should be understood that the terms "left," "right," "upper," "lower," "top," "bottom," "front," "rear," "inner," "outer," "back," and "middle," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. It should be noted that in the above embodiments, the terms "first" and "second" do not represent an absolute distinction in structure and / or function, nor do they represent a sequential execution order, but are merely for the convenience of description.

[0067] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application, such as the application of this utility model to the purification of other heat-sensitive liquid materials by operators according to actual conditions, should be included within the protection scope of this application.

Claims

1. A demister for facilitating the purification of 3-methylthiopropionaldehyde, characterized in that: The demister (13) is provided with a tank (133). According to the gas flow direction, a baffle demister (134) and a wire mesh demister (135) are installed at intervals inside the tank (133). A baffle plate (136) is connected to the air inlet of the tank (133), and an MMP gas outlet pipe (137) is connected to the air outlet of the tank (133).

2. The demister for facilitating the purification of 3-methylthiopropionaldehyde according to claim 1, characterized in that, The angle (α) between the baffle (136) and the plane where the air inlet of the tank (133) is located is 45° to 65°; the orthographic projection area of ​​the baffle (136) on the plane where the air inlet of the tank (133) is located is 1 / 2 to 2 / 3 of the area of ​​the plane where the air inlet of the tank (133) is located.

3. The demister for facilitating the purification of 3-methylthiopropionaldehyde according to claim 1, characterized in that, The distance (d) between the baffle plate demister (134) and the wire mesh demister (135) is controlled at 100-150 mm.

4. A demister for facilitating the purification of 3-methylthiopropionaldehyde according to any one of claims 1-3, characterized in that, The surface roughness Ra of the baffle plate in the baffle demister (134) is ≤0.8μm; the porosity of the wire mesh demister (135) is >97%, the pressure drop is 0.2~0.5 KPa, the wire diameter is 0.2 mm~0.25 mm, and the specific surface area is controlled at 200~300 m². 2 / m 3 .

5. A demister for facilitating the purification of 3-methylthiopropionaldehyde according to claim 1, characterized in that, Both the baffle plate demister (134) and the wire mesh demister (135) are made of austenitic stainless steel.

6. A distillation column for purifying 3-methylthiopropionaldehyde, the distillation column comprising a column body, the column body comprising, from top to bottom, an upper column top (1), a rectification section (2), a stripping section (3), a falling film evaporator, and a column bottom (6). The top of the upper tower (1) is connected to a light component discharge port (7). The rectification section (2) is equipped with a first packing (21); A column top distributor (8) is installed between the upper column top (1) and the rectification section (2), and the column top distributor (8) is connected to a reflux feed inlet (9). The stripping section (3) is equipped with a second packing material (31); A feed distributor (10) is installed between the stripping section (3) and the rectification section (2), and the feed distributor (10) is connected to an MMP crude product inlet (11). The bottom of the tower (6) is connected to a scrap material outlet (12). Its features are, The falling film evaporator is provided with a first falling film evaporator (4) and a second falling film evaporator (5). The first falling film evaporator (4) is spaced above the second falling film evaporator (5). The first falling film evaporator (4) is connected to a first steam inlet (41) and a first steam condensate outlet (42). The second falling film evaporator (5) is connected to a second steam inlet (51) and a second steam condensate outlet (52). The tower body also includes a demister (13), which is provided with a tank (133). According to the gas flow direction, a baffle demister (134) and a wire mesh demister (135) are installed at intervals inside the tank (133). A baffle plate (136) is connected to the air inlet of the tank (133), and an MMP gas outlet pipe (137) is connected to the air outlet of the tank (133). The demister (13) is provided with a first gas phase discharge demister (131) and a second gas phase discharge demister (132). The first gas phase discharge demister (131) is installed between the first falling film evaporator (4) and the second falling film evaporator (5), and the MMP gas discharge pipe (137) of the first gas phase discharge demister (131) is connected to the first MMP gas discharge port (14). The second gas phase discharge demister (132) is installed inside the tower (6), and the MMP gas discharge pipe (137) of the second gas phase discharge demister (132) is connected to the second MMP gas discharge port (15).

7. A distillation column for facilitating the purification of 3-methylthiopropionaldehyde according to claim 6, characterized in that, The angle (α) between the baffle (136) and the plane where the air inlet of the tank (133) is located is 45° to 65°; the orthographic projection area of ​​the baffle (136) on the plane where the air inlet of the tank (133) is located is 1 / 2 to 2 / 3 of the area of ​​the plane where the air inlet of the tank (133) is located.

8. A distillation column for facilitating the purification of 3-methylthiopropionaldehyde according to claim 6, characterized in that, The distance (d) between the baffle plate demister (134) and the wire mesh demister (135) is controlled at 100-150 mm.

9. A distillation column for facilitating the purification of 3-methylthiopropionaldehyde according to claim 6, characterized in that, The surface roughness Ra of the baffle plate in the baffle demister (134) is ≤0.8μm; the porosity of the wire mesh demister (135) is >97%, the pressure drop is 0.2~0.5 KPa, the wire diameter is 0.2 mm~0.25 mm, and the specific surface area is controlled at 200~300 m². 2 / m 3 .

10. A distillation column for facilitating the purification of 3-methylthiopropional according to claim 6, characterized in that, The first packing (21) and the second packing (31) are both wire mesh corrugated structured packing; the baffle plate demister (134) and the wire mesh demister (135) are both made of austenitic stainless steel.

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