Liquid-phase phosgenation reaction equipment
By designing a liquid-phase phosgenation reaction device, utilizing a falling film head to form a liquid film countercurrent convection and a stirring device, the problems of large phosgene consumption and low utilization rate were solved, and efficient isocyanate production was achieved.
Patent Information
- Application Number
- CN202422628460.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-10-30
AI Technical Summary
Traditional liquid-phase phosgene synthesis methods using isocyanates suffer from problems such as high phosgene consumption, low utilization rate, and low product yield.
Design a liquid-phase phosgenation reaction device, including a reaction vessel, a first condenser and a second condenser. Utilize a falling film head to form a countercurrent liquid film convection, and combine it with a stirring device and a reflux device to improve the utilization rate of gaseous raw materials.
It improved the utilization rate and product yield of phosgene, reduced the amount of phosgene used, and improved the production efficiency of isocyanates.
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Figure CN223505283U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of phosgenation reaction equipment technology, and in particular to a liquid-phase phosgenation reaction equipment. Background Technology
[0002] Currently, two common processes for preparing isocyanates are the gas-phase phosgene method and the liquid-phase phosgene method. The gas-phase phosgene method requires the vaporization of liquid amines at high temperatures, followed by a reaction with phosgene to produce isocyanates. This process has high requirements for the purity and form of the raw amines and the equipment, resulting in higher production costs. In contrast, the liquid-phase phosgene method has a simpler overall process route, lower requirements for raw materials and equipment, and offers higher economic benefits.
[0003] However, traditional liquid-phase phosgene synthesis methods for isocyanates suffer from problems such as high phosgene consumption, low phosgene utilization, and low product yield. Utility Model Content
[0004] Therefore, it is necessary to provide a liquid-phase phosgenation reaction device that can be applied to the liquid-phase phosgene synthesis of isocyanates, and can achieve high phosgene utilization and high product yield with low phosgene usage.
[0005] This application provides a liquid phase phosgenation reaction apparatus, including: a reaction vessel, a first condenser, and a second condenser;
[0006] The reactor is equipped with an air inlet device and a first air outlet device. The air inlet device is used to input gas into the reactor, and the air outlet device is used to transport the gas in the reactor to the first condensation device.
[0007] The first condensing device is used to condense the gas, and the first condensing device is provided with a second gas outlet device and a liquid outlet device; the liquid outlet device is used to transport the condensed liquid to the second condensing device, and the second gas outlet device is used to transport the uncondensed gas to the second condensing device.
[0008] The second condensing device is used to condense the gas. The second condensing device is provided with a falling film head. The output end of the liquid outlet device is connected to the input end of the falling film head. The falling film head is provided with a liquid outlet facing the inner wall of the second condensing device. The falling film head is used to form a liquid film that can slide down the inner wall of the second condensing device. The height of the liquid outlet of the falling film head is higher than the height of the output end of the second gas outlet device.
[0009] The second condensation device is also equipped with a reflux device, which is used to return the liquid to the reaction vessel.
[0010] In some embodiments, the liquid phase phosgenation reaction apparatus further includes a stirring device disposed inside the reaction vessel;
[0011] The stirring device includes a stirring shaft and a first stirring element and a second stirring element spaced apart on the stirring shaft; the first stirring element is closer to the bottom of the reactor than the second stirring element, the first stirring element is used to generate an axial flow field, and the second stirring element is used to generate a radial flow field.
[0012] In some embodiments, the first agitator includes a propeller, and the second agitator includes a disc turbine blade.
[0013] In some embodiments, the ratio of the maximum diameter of the first agitator to the diameter of the reactor is (5~8):10.
[0014] In some embodiments, the liquid-phase phosgenation reaction apparatus further includes a defoaming component disposed on the stirring shaft, the defoaming component being used to break up air bubbles; the defoaming component is further away from the bottom of the reaction vessel than the second stirring component.
[0015] In some embodiments, the liquid-phase phosgenation reaction apparatus further includes a dispensing device disposed within the reaction vessel; the dispensing device is located closer to the bottom of the reaction vessel than the stirring element used to generate an axial flow field.
[0016] The output end of the air intake device is connected to the input end of the material distribution device, and the material distribution device has multiple spaced-apart discharge holes.
[0017] In some embodiments, the output of the reflux device is connected to the input of the dispensing device.
[0018] In some embodiments, the dispensing device is annular, with multiple discharge holes spaced apart on one side of the dispensing device facing the bottom of the reactor.
[0019] In some embodiments, the liquid outlet device has a first U-bend that can form a liquid seal within the liquid outlet device.
[0020] In some embodiments, the reflux device has a second U-bend that can form a liquid seal within the reflux device.
[0021] In the aforementioned liquid-phase phosgenation reaction equipment, gaseous raw materials are introduced into the reactor through an inlet device, enabling gas-liquid two-phase reactions or gas-liquid-solid three-phase reactions to occur within the reactor. Unreacted gases, reaction-generated gases, and volatile solvents in the reactor are transported to the first condenser via an outlet device for condensation. The condensed liquid from the first condenser is then transported to the second condenser via a liquid outlet device. When the condensed liquid is transported to the second condenser, it is discharged through multiple outlets facing the inner wall of the second condenser via a falling film head, forming a liquid film that slides down the inner wall of the second condenser. Simultaneously, the outlet height of the falling film head is higher than the output height of the second outlet device, causing the uncondensed gas from the first condenser to rise as it is transported to the second condenser via the outlet device. The rising gas interacts with the liquid film sliding down the inner wall of the second condenser, creating a counter-current flow that allows the liquid to absorb the gas. Simultaneously, the second condenser also performs secondary condensation on any unabsorbed liquid, which mixes with the liquid film and is then returned to the reactor via a reflux device to continue the reaction. This liquid-phase phosgenation reaction equipment improves the utilization rate of gaseous feedstock, resulting in a higher product yield. Furthermore, the liquid-phase phosgenation reaction equipment of this application can be applied to the liquid-phase phosgene synthesis of isocyanates, achieving both high phosgene utilization and high product yield. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of a liquid-phase phosgenation reaction apparatus provided in an embodiment of this application;
[0023] Figure 2 for Figure 1 A magnified view of the structure within the dashed box;
[0024] Figure 3 This is a schematic diagram of the structure of a stirring device provided in one embodiment of this application;
[0025] Figure 4 This is a schematic diagram of the structure of the first stirring element, the second stirring element, and the defoaming element on a stirring device provided in an embodiment of this application.
[0026] Explanation of reference numerals in the attached figures
[0027] 1. Reactor; 2. First condenser; 3. Second condenser; 4. Liquid outlet; 5. Anti-surge device; 6. Falling film head; 7. Gas outlet; 8. Distributor; 9. Stirring device; 10. Gas inlet device; 11. Reflux device; 12. First agitator; 13. Second agitator; 14. Defoamer; 15. First gas outlet; 16. Second gas outlet; 17. First U-bend; 18. Second U-bend. Detailed Implementation
[0028] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.
[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0033] Reference Figure 1, Figure 2 As shown, one embodiment of this application provides a liquid-phase phosgenation reaction apparatus, including: a reaction vessel 1, a first condensing device 2, and a second condensing device 3; the reaction vessel 1 is provided with an inlet device 10 and a first outlet device 15, the inlet device 10 is used to input gas into the reaction vessel 1, and the outlet device is used to transport the gas in the reaction vessel 1 to the first condensing device 2; the first condensing device 2 is used to condense the gas, and the first condensing device 2 is provided with a second outlet device 16 and a liquid outlet device 4; the liquid outlet device 4 is used to transport the condensed liquid to the second condensing device 3, and the second outlet device 16... The device is used to transport uncondensed gas to the second condensing device 3; the second condensing device 3 is used to condense the gas, and a falling film head 6 is provided inside the second condensing device 3. The output end of the liquid outlet device 4 is connected to the input end of the falling film head 6; the falling film head 6 is provided with a liquid outlet facing the inner wall of the second condensing device 3, and the falling film head 6 is used to form a liquid film that can slide down the inner wall of the second condensing device 3; the height of the liquid outlet of the falling film head 6 is higher than the height of the output end of the second gas outlet device 16; the second condensing device 3 is also provided with a reflux device 11, which is used to return the liquid to the reaction vessel 1.
[0034] In the aforementioned liquid-phase phosgenation reaction equipment, gaseous raw materials are introduced into the reaction vessel 1 through the gas inlet device 10, enabling gas-liquid two-phase reactions or gas-liquid-solid three-phase reactions to occur in the reaction vessel 1. Unreacted gases, reaction-generated gases, and volatile solvents in the reaction vessel 1 are transported to the first condensing device 2 via the gas outlet device for condensation. The condensed liquid obtained in the first condensing device 2 is then transported to the second condensing device 3 via the liquid outlet device 4. When the condensed liquid is transported to the second condensing device 3, it can be discharged onto the inner wall of the condensing device through multiple liquid outlets facing the inner wall of the second condensing device 3 via the falling film head 6, forming a liquid film that can slide down the inner wall of the second condensing device 3. Simultaneously, the liquid outlet of the falling film head 6 is positioned higher than the output end of the second gas outlet device 16, causing the uncondensed gas in the first condensing device 2 to rise from the bottom when transported to the second condensing device 3 via the gas outlet device. The rising gas interacts with the liquid film sliding down the inner wall of the second condenser 3, creating a counter-current flow that allows the liquid to absorb the gas. Simultaneously, the second condenser 3 also performs secondary condensation on any unabsorbed liquid, forming a liquid that mixes with the liquid film and is then returned to the reactor 1 via the reflux device 11 to continue the reaction. This liquid-phase phosgenation reaction equipment improves the utilization rate of gaseous feedstock, thereby achieving a higher product yield.
[0035] It is understood that phosgene, also known as carbonyl chloride, has the chemical formula COCl2. The liquid-phase phosgenation reaction apparatus of this application can be applied to liquid-phase phosgenation reactions. Exemplarily, the liquid-phase phosgenation reaction apparatus of this application can be applied to the liquid-phase phosgene synthesis of isocyanates: after feeding, phosgene is slowly introduced into the reactor. The hydrogen chloride and other gases produced in the reaction, along with the escaping phosgene, carry a small amount of solvent into the first condenser. After being cooled, the first condenser separates the phosgene into two phases: a liquid phase (mainly solvent) and a gas phase (mainly phosgene and hydrogen chloride). The liquid phase enters the second condenser, where the solvent forms a film and continuously absorbs the phosgene from the reverse-flowing gas phase. The unabsorbed phosgene is further condensed into liquid phosgene and flows back into the reactor with the saturated solvent to continue participating in the reaction. This cycle continues until the reaction is complete. By using this liquid-phase phosgenation reaction apparatus, a high phosgene utilization rate and a high isocyanate product yield can be obtained.
[0036] Reference Figure 3 As shown, in some embodiments, the liquid phase phosgenation reaction apparatus further includes a stirring device 9, which is disposed inside the reaction vessel 1. The stirring device 9 includes a stirring shaft and a first stirring element 12 and a second stirring element 13 spaced apart on the stirring shaft. The first stirring element 12 is closer to the bottom of the reaction vessel 1 than the second stirring element 13. The first stirring element 12 is used to generate an axial flow field, and the second stirring element 13 is used to generate a radial flow field.
[0037] The first agitator 12, located near the bottom of the reactor 1, generates an axial flow field, pushing the reaction liquid in the reactor 1 to the bottom and then moving upwards along the inner wall of the reactor 1, thus achieving bottom-to-top circulation of the reaction liquid. The second agitator 13 generates a radial flow field, pushing the reactants near the agitator 9 radially towards the side wall of the reactor 1, allowing for better mixing with the reaction liquid moving upwards along the inner wall of the reactor 1, thereby achieving uniform mixing of the gas-liquid two-phase or gas-liquid-solid three-phase mixture. Furthermore, this enhances the contact between phosgene and other raw materials, improving the utilization rate of phosgene.
[0038] Reference Figure 4 As shown, in some embodiments, the first agitator 12 includes a propeller, and the second agitator 13 includes a disc turbine blade.
[0039] In some embodiments, the ratio of the maximum diameter of the first stirring element 12 to the diameter of the reactor 1 is (5~8):10.
[0040] The ratio of the maximum diameter of the first agitator 12 to the diameter of the reactor 1 is within the aforementioned range, which allows the liquid level rise to be within a suitable range, thereby achieving a higher reaction yield. Optionally, the ratio of the maximum diameter of the first agitator 12 to the diameter of the reactor 1 is 5:10, 5.5:10, 6:10, 6.5:10, 7:10, 7.5:10, or 8:10, or the ratio can be within any two of the above ratios.
[0041] In some embodiments, the liquid phase phosgenation reaction apparatus further includes a defoaming element 14, which is disposed on the stirring shaft and is used to break up bubbles; the defoaming element 14 is further away from the bottom of the reaction vessel 1 than the second stirring element 13.
[0042] During the photochemical reaction, a large amount of sparingly soluble hydrogen chloride gas is generated, along with the escape of phosgene. These gases form dense small bubbles. Due to surface tension, these bubbles do not break immediately; instead, they carry liquid and solid upwards, sometimes overflowing the reactor or even causing material overflow. These small bubbles can be broken by the defoaming component 14.
[0043] In some embodiments, the defoaming element 14 includes radially shaped blades.
[0044] It is understandable that the second stirring component 13 can be one or more, and the defoaming component 14 can also be one or more.
[0045] In some embodiments, the liquid phase phosgenation reaction apparatus further includes a dispensing device 8, which is disposed inside the reactor 1; the dispensing device 8 is located closer to the bottom of the reactor 1 than the agitator used to generate an axial flow field; the output end of the air inlet device 10 is connected to the input end of the dispensing device 8, and the dispensing device 8 has a plurality of spaced-apart discharge holes.
[0046] By connecting the output end of the gas inlet device 10 to the input end of the distribution device 8, the gaseous raw material introduced into the reactor 1 can be more evenly distributed within the reactor 1 through the multiple spaced discharge holes of the distribution device 8. Simultaneously, compared to the agitator used to generate an axial flow field, the distribution device 8 is closer to the bottom of the reactor 1, which also increases the contact between the gaseous raw material and the liquid raw material in the reactor 1 after the gas is introduced. When the liquid-phase phosgenation reaction equipment of this application is applied to a liquid-phase phosgenation reaction, the contact area and residence time between phosgene and other materials can be increased, thereby improving the utilization rate of phosgene.
[0047] Optionally, the number of discharge holes is 5 or more. Further optionally, the number of discharge holes is 5 to 15. Further optionally, the number of discharge holes is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15.
[0048] In some embodiments, the output of the reflux device 11 is connected to the input of the material distribution device 8.
[0049] In some embodiments, the dispensing device 8 is annular, and multiple discharge holes are spaced apart on one side of the dispensing device 8 facing the bottom of the reactor 1.
[0050] The discharge holes are spaced apart on the side of the distribution device 8 facing the bottom of the reactor 1, which can prevent the holes from being blocked when solid materials are added from the top; at the same time, it can prevent liquid from accumulating in the distribution device 8 when the reaction liquid is discharged; and it can also make phosgene flow to the bottom, increasing the contact area and residence time between phosgene and materials, and improving the utilization rate of phosgene.
[0051] In some embodiments, the dispensing device 8 is a tubular dispensing device 8.
[0052] In some embodiments, the diameter of the dispensing device 8 is 20 mm or more.
[0053] Optionally, the diameter of the material separating device 8 is 20mm to 200mm. More preferably, the diameter of the material separating device 8 is 20mm, 40mm, 60mm, 80mm, 100mm, 120mm, 140mm, 160mm, 180mm or 200mm, or the diameter of the material separating device 8 may be within the range of any two of the above diameters.
[0054] In some embodiments, the diameter of the discharge hole is 1 mm or more.
[0055] Optionally, the diameter of the discharge hole is 1mm to 10mm. More preferably, the diameter of the discharge hole is 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, or the diameter of the discharge hole may be within the range of any two of the above diameters.
[0056] In some embodiments, the second condensing device 3 also has an outlet 7 for discharging uncondensed gas from the second condensing device 3.
[0057] In some embodiments, the second condensation device 3 further includes an anti-surge device 5, which surrounds the falling film head 6.
[0058] In some embodiments, the liquid outlet device 4 has a first U-bend 17, which is capable of forming a liquid seal within the liquid outlet device 4.
[0059] In some embodiments, the reflux device 11 has a second U-bend 18 that can form a liquid seal within the reflux device 11.
[0060] Another embodiment of this application provides the application of the liquid phase phosgenation reaction apparatus of any of the above claims as a reactor in a liquid phase phosgenation reaction.
[0061] Another embodiment of this application provides the application of the liquid-phase phosgenation reaction apparatus of any of the above claims as a reactor in the liquid-phase synthesis of isocyanates.
[0062] Another embodiment of this application provides a method for preparing isocyanate using the above-described liquid-phase phosgenation reaction apparatus, comprising the following steps:
[0063] Organic solvent is added into reaction vessel 1, and the liquid level of organic solvent is controlled between the defoaming component 14 and the second stirring component 13.
[0064] With stirring on, the amine raw material is added into reactor 1;
[0065] Slowly introduce phosgene into reactor 1;
[0066] The phosgene and solvent that escaped from the reaction are returned to the reaction vessel 1 through the first condenser 2 and the second condenser 3 for recycling until the reaction is completed.
[0067] In some embodiments, the organic solvent includes at least one of toluene, chlorobenzene, o-dichlorobenzene, dimethyl carbonate, and diethyl carbonate.
[0068] In some embodiments, the amine raw material includes at least one of amine or amino hydrochloride, amino sulfate, amino carbonate and amino nitrate.
[0069] In some embodiments, the amine raw material includes at least one of hexamethylenediamine or a salt thereof, isophoronediamine or a salt thereof, diphenylmethanediamine or a salt thereof, pentanediamine or a salt thereof, toluenediamine or a salt thereof, and m-phenylenediamine or a salt thereof.
[0070] The following are specific embodiments.
[0071] Example 1
[0072] This embodiment uses, as follows: Figure 1The liquid-phase phosgenation reactor shown prepares pentanediisocyanate via liquid-phase phosgenation. The diameter ratio of the first stirrer to the reactor is (5-8):10, and it includes an anti-foaming component. A certain amount of solvent and pentanediamine sulfate are added to the reactor through the feed port; to prevent agglomeration, the maximum concentration of pentanediamine sulfate is 40 wt%. Then, 1.2 times the theoretically required amount of phosgene is introduced at 65°C. The liquid level is observed to rise by a maximum of 20%. The reflux temperature of the first and second condensers is set at -10°C to 10°C. Subsequently, the reactor temperature is raised to 180°C, and the reaction is terminated after 6 hours. The reaction solution is then subjected to subsequent distillation, and the calculated yield of pentanediisocyanate is 95%.
[0073] Example 2
[0074] The only difference between Example 2 and Example 1 is that 1.5 times the theoretically required amount of phosgene is introduced. The calculated yield of glutaraldehyde diisocyanate is 95.3%.
[0075] Example 3
[0076] The only difference between Example 3 and Example 1 is that the liquid reflux temperature of the first and second condensing devices was set to 15°C to 25°C. The reaction was terminated after 8.6 hours, and the calculated yield of glutaryl isocyanate was 87.2%.
[0077] Example 4
[0078] The only difference between Example 4 and Example 1 is that the liquid reflux temperature of the first and second condensing devices was set to 15°C~25°C, and 2.5 times the theoretically required amount of phosgene was introduced. The reaction was terminated after 7.2 hours, and the calculated yield of glutaryl isocyanate was 91.5%.
[0079] Example 5
[0080] The only difference between Example 5 and Example 1 is that the diameter ratio of the first stirrer to the reactor is 1:3. To avoid agglomeration, the maximum concentration of pentanediamine sulfate is 20 wt%, and phosgene, three times the theoretical required amount, is introduced. The liquid level is observed to rise by up to 50%. The reaction is terminated after 9 hours, and the calculated yield of pentanediisocyanate is 88.4%.
[0081] Example 6
[0082] The only difference between Example 6 and Example 1 is that no defoaming device was used, and 2.5 times the theoretically required amount of phosgene was introduced, resulting in a maximum liquid level rise of 80%. The reaction was terminated after 7 hours, and the calculated yield of glutaryl isocyanate was 89.5%.
[0083] Comparative Example 1
[0084] The only difference between Comparative Example 1 and Example 1 is the absence of a second condenser. The reaction was terminated after 6 hours, and the calculated yield of glutaryl isocyanate was 45%.
[0085] Comparative Example 2
[0086] The only difference between Comparative Example 2 and Example 1 is that a conventional stirring paddle was used, the diameter ratio of the first stirring element to the reactor diameter was 1:3, and there was no second condenser. To prevent agglomeration, the maximum concentration of pentanediamine sulfate was 20 wt%, and phosgene, 12 times the theoretically required amount, was introduced. The liquid level was observed to rise by a maximum of 95%. The reaction was terminated after 12 hours, and the calculated yield of pentanediisocyanate was 75%.
[0087] The results of each embodiment and comparative example are compared in the table below:
[0088]
[0089] A comparison of the results from Examples 1 and 2 shows that the phosgene reflux effect of the liquid-phase phosgenation reaction equipment is excellent, and increasing the amount of phosgene used does not significantly reduce the reaction time or increase the reaction yield.
[0090] A comparison of the results from Examples 1 to 4 shows that the lower the reflux temperature, the smaller the phosgene requirement, the shorter the reaction time, and the higher the reaction yield.
[0091] A comparison of the results from Examples 1, 2, and 5 shows that the larger the diameter of the first stirring element, the smaller the liquid level rise, the smaller the phosgene requirement, the shorter the reaction time, the higher the material concentration, and the higher the reaction yield.
[0092] A comparison of the results from Examples 1, 2, and 6 shows that the presence of the defoaming component can reduce the liquid level rise, decrease the amount of phosgene used, shorten the reaction time, and increase the reaction yield.
[0093] The results from Example 1 and Comparative Example 1 show that, under the same conditions, the reaction yield of the liquid phase phosgenation reaction apparatus with a second condenser, i.e., a falling film head, is much greater than that of the reaction apparatus without a falling film head.
[0094] The results of Examples 1 to 4 and Comparative Example 2 show that the liquid phase phosgenation reaction equipment has significant advantages over the traditional batch reactor in terms of filling capacity, phosgene demand, reaction time, and reaction yield.
[0095] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0096] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.
Claims
1. A liquid-phase phosgenation reaction apparatus, characterized in that, include: Reactor, first condenser and second condenser; The reactor is equipped with an air inlet device and a first air outlet device. The air inlet device is used to input gas into the reactor, and the air outlet device is used to transport the gas in the reactor to the first condensation device. The first condensing device is used to condense the gas, and the first condensing device is provided with a second gas outlet device and a liquid outlet device; the liquid outlet device is used to transport the condensed liquid to the second condensing device, and the second gas outlet device is used to transport the uncondensed gas to the second condensing device. The second condensing device is used to condense the gas. The second condensing device is provided with a falling film head. The output end of the liquid outlet device is connected to the input end of the falling film head. The falling film head is provided with a liquid outlet facing the inner wall of the second condensing device. The falling film head is used to form a liquid film that can slide down the inner wall of the second condensing device. The height of the liquid outlet of the falling film head is higher than the height of the output end of the second gas outlet device. The second condensation device is also equipped with a reflux device, which is used to return the liquid to the reaction vessel.
2. The liquid-phase phosgenation reaction apparatus according to claim 1, characterized in that, The liquid-phase phosgenation reaction equipment also includes a stirring device, which is disposed inside the reaction vessel; The stirring device includes a stirring shaft and a first stirring element and a second stirring element spaced apart on the stirring shaft; the first stirring element is closer to the bottom of the reactor than the second stirring element, the first stirring element is used to generate an axial flow field, and the second stirring element is used to generate a radial flow field.
3. The liquid-phase phosgenation reaction apparatus according to claim 2, characterized in that, The first agitator includes a helical propeller, and the second agitator includes a disc turbine blade.
4. The liquid-phase phosgenation reaction apparatus according to claim 2, characterized in that, The ratio of the maximum diameter of the first stirring element to the diameter of the reactor is (5~8):
10.
5. The liquid-phase phosgenation reaction apparatus according to claim 2, characterized in that, The liquid phase phosgenation reaction equipment also includes a defoaming component, which is disposed on the stirring shaft and is used to break up bubbles; compared with the second stirring component, the defoaming component is further away from the bottom of the reaction vessel.
6. The liquid-phase phosgenation reaction apparatus according to claim 2, characterized in that, The liquid-phase phosgenation reaction equipment also includes a material distribution device, which is disposed inside the reaction vessel; compared to the first stirring element, the material distribution device is closer to the bottom of the reaction vessel; The output end of the air intake device is connected to the input end of the material distribution device, and the material distribution device has multiple spaced-apart discharge holes.
7. The liquid-phase phosgenation reaction apparatus according to claim 6, characterized in that, The output end of the reflux device is connected to the input end of the material distribution device.
8. The liquid-phase phosgenation reaction apparatus according to claim 6, characterized in that, The material distribution device is ring-shaped, with multiple discharge holes spaced apart on one side of the material distribution device facing the bottom of the reactor.
9. The liquid-phase phosgenation reaction apparatus according to any one of claims 1 to 8, characterized in that, The liquid outlet device has a first U-shaped bend, which can form a liquid seal within the liquid outlet device.
10. The liquid-phase phosgenation reaction apparatus according to any one of claims 1 to 8, characterized in that, The reflux device has a second U-bend, which can form a liquid seal within the reflux device.