Efficient synthesis system for preparing trimethylolpropane and method

Abstract

An efficient synthesis system for preparing trimethylolpropane and a method. The system comprises a multi-stage reactor (13). A plurality of intensified reactors (14, 20) are vertically provided inside the multi-stage reactor (13), and the plurality of intensified reactors (14, 20) are sequentially and uniformly arranged from top to bottom. An n-butyraldehyde feeding port (1) is formed in the top of the multi-stage reactor (13), and the n-butyraldehyde feeding port (1) leads into the intensified reactors (14, 20). A mixed liquid feeding port (16) and a sodium hydroxide feeding port (15) are respectively formed in two sides of the top of the multi-stage reactor (13), and a first discharging port (28) is formed in the bottom of the multi-stage reactor (13). In the efficient synthesis system, a condensation reaction can be completed to the maximum extent by means of the provision of the multi-stage reactor (13) and the use of intensification units (22, 25), and the contact area between raw materials is increased by means of the intensification units (22, 25), thereby increasing the reaction rate and the product yield. Moreover, reaction heat can be removed in a timely manner by employing an external circulation system, thereby accurately controlling a reaction temperature, reducing generation of reaction byproducts, and facilitating subsequent purification and separation.

Description

High-efficiency synthesis system and method for preparing trimethylolpropane TECHNICAL FIELD

[0001] The present application belongs to the technical field of trimethylolpropane production, and in particular to a high-efficiency synthesis system and method for trimethylolpropane. BACKGROUND

[0002] Trimethylolpropane is an important fine chemical product and organic chemical raw material. Currently, most trimethylolpropane manufacturers on the market mainly use the Cannizzaro method for production. The production technology is increasingly mature, but there are still many problems. In the Cannizzaro method, calcium hydroxide is mostly used as a catalyst, but the solubility of calcium hydroxide in water is small, and a large part of it will precipitate in the tower kettle during rectification, affecting normal operation. When sodium hydroxide is used as a catalyst, sodium formate will be produced due to the combination of formic acid, which will continuously enrich in the tower kettle during rectification, thereby increasing the viscosity of the kettle liquid and affecting normal operation. The reaction of this method in the traditional process still has problems such as high temperature, high pressure, many by-products, low product purity, and low product yield. Therefore, it is crucial to design a synthesis system for trimethylolpropane to reduce energy consumption and improve the yield of trimethylolpropane.

[0003] In view of this, the present application is proposed.

[0004] SUMMARY

[0005] The first object of the present application is to provide a high-efficiency synthesis system for trimethylolpropane. The high-efficiency synthesis system of the present application can maximize the completion of the condensation reaction through the arrangement of multiple intensified reactors and the application of an intensified unit. The intensified unit increases the contact area between raw materials, thereby improving the reaction rate and product yield. In addition, the reaction heat can be removed in time through the external circulation system, thereby accurately controlling the reaction temperature, reducing the generation of reaction by-products, and facilitating subsequent purification and separation.

[0006] The second object of the present application is to provide a method for the reaction of a high-efficiency synthesis system for trimethylolpropane. The method is simple to operate, has mild operating conditions, high product yield, and high purity.

[0007] In order to achieve the above objects of the present application, the following technical solutions are adopted:

[0008] The application discloses a high-efficiency synthesis system for preparing trimethylolpropane, which comprises a multistage reactor, wherein a plurality of reinforced reactors are vertically arranged in the multistage reactor, the reinforced reactors are uniformly arranged from top to bottom, a n-butyl aldehyde feeding port is arranged at the top of the multistage reactor and is connected to the reinforced reactors, a mixed liquid feeding port and a sodium hydroxide feeding port are arranged at the two sides of the top of the multistage reactor respectively, and a first discharging port is arranged at the bottom of the multistage reactor.

[0009] Preferably, as a further implementable scheme, the number of the reinforced reactors is two, a first reinforced reactor is arranged at the bottom of the multistage reactor, and a second reinforced reactor is arranged at the center of the multistage reactor.

[0010] Preferably, as a further implementable scheme, a first reinforced unit for increasing the phase boundary area between two phases and a first partition plate are arranged in the first reinforced reactor, and the first partition plate is arranged directly below the first reinforced unit.

[0011] Preferably, as a further implementable scheme, a first circulating pump feeding port is arranged above the first reinforced unit and is connected to the first reinforced unit, and a first circulating pump is connected to the first reinforced unit through the first circulating pump feeding port.

[0012] Nowadays, the raw materials for preparing trimethylolpropane are mostly n-butyl aldehyde and methanol, but there are problems of low yield, high energy consumption and low product purity in the synthesis technology of trimethylolpropane. Therefore, in order to solve the above-mentioned problems, the application is provided with a plurality of reinforced reactors, a reinforced unit is arranged, the reinforced unit in the reinforced reactor is utilized to increase the turbulent flow and mixed flow between two phases, and the reinforced reactors are arranged at the middle and bottom of the multistage reactor, so that the reaction is more thorough and sufficient, and the product yield is higher.

[0013] The application improves the phase interface area between raw materials by arranging a second intensifier reactor at the center of the multistage reactor, so that the raw materials are more uniformly dispersed. Since the water solution of n-butyl aldehyde and formaldehyde used is a two-phase system that is not miscible with each other, the reaction is not complete due to the immiscibility between the two in the traditional trimethylolpropane. The application improves the phase interface area between n-butyl aldehyde and formaldehyde by arranging a second intensifier reactor at the center of the multistage reactor, so that formaldehyde and n-butyl aldehyde can be mixed for a longer time, increasing the reaction time between the two, thereby improving the progress and yield of the reaction process. By arranging multiple intensifier reactors inside the multistage reactor, the condensation of n-butyl aldehyde and formaldehyde can be ensured to a greater extent, improving the conversion rate of n-butyl aldehyde while reducing the generation of by-products, facilitating subsequent separation. The arrangement of the first intensifier reactor at the bottom of the multistage reactor further allows the reaction to be complete. This is because after the condensation reaction in the second intensifier reactor, the reaction of the raw materials does not produce the final product, but an intermediate product. In order to strengthen the reaction of the intermediate to trimethylolpropane, the application arranges a first intensifier reactor at the bottom of the multistage reactor to further strengthen the condensation reaction between the raw materials, so that the intermediate can be more fully converted into the product trimethylolpropane. When the subsequent device of the application separates the product produced in the multistage reactor, the incompletely reacted raw materials will pass through the external circulation system and the intensifier unit to strengthen the phase interface area between the substances in the multistage reactor, so that the raw materials entering the multistage reactor after separation can more fully participate in the reaction.

[0014] Preferably, as a further implementable solution, a second intensifier unit and a second partition are arranged in the second intensifier reactor, and the second intensifier unit is arranged directly below the second partition.

[0015] Preferably, as a further implementable solution, a formaldehyde feeding port is arranged above the second intensifier unit and is connected to the second intensifier unit, a second circulating pump is connected to the second intensifier unit through the formaldehyde feeding port, a heat exchanger and a mixer are sequentially connected between the second circulating pump and the second intensifier unit, and a metering pump feeding port is arranged between the heat exchanger and the mixer, and a metering pump is connected to the mixer through the metering pump feeding port.

[0016] The application sets a second intensification unit inside the second intensification reactor, when the n-butyl aldehyde and sodium hydroxide aqueous solution catalyst entering the multi-stage reactor inside through the n-butyl aldehyde feeding port are passed into the second intensification reactor, mixed with the formaldehyde passed into the second intensification reactor after metering by the metering pump, and then broken into small droplets by the second intensification unit, so that the phase boundary area between the originally mutually insoluble n-butyl aldehyde and formaldehyde is increased, the reaction rate is improved, the two are fully reacted, and then the material already formed into small droplets can be uniformly dispersed by the second partition plate in the second intensification reactor, so that the reaction between the materials is further accelerated. In order to reduce the temperature inside the multi-stage reactor during the reaction, thereby avoiding the generation of by-products, the application sets an external circulation system, reciprocates between the circulating pump, heat exchanger and mixer, so that the temperature inside the multi-stage reactor is greatly reduced, and the generation of by-products is reduced. During the reaction in the second intensification reactor, 30% of the reaction liquid is extracted by the second circulating pump through the heat exchanger connected with the second circulating pump, so that the reaction temperature inside the multi-stage reactor is greatly reduced, and the generation of by-products is reduced. After heat exchange, the formaldehyde mixed by the mixer after being quantitatively added by the metering pump enters the second intensification reactor through the formaldehyde feeding port above the second intensification unit, and is fully mixed with the n-butyl aldehyde and sodium hydroxide aqueous solution entering through the n-butyl aldehyde feeding port above the multi-stage reactor. Through such an external circulation system, the temperature inside the multi-stage reactor can always be kept at 40-50 DEG C.

[0017] After the preliminary reaction treatment of the reaction liquid in the second intensification reactor, the reaction liquid falls to the first intensification reactor arranged at the bottom of the multi-stage reactor, the condensation reaction is strengthened by the first intensification reactor at the bottom of the multi-stage reactor, so that the intermediate is converted into the final product, and the condensation reaction is strengthened by the first intensification unit arranged in the first intensification reactor, and the first partition plate arranged in the first intensification reactor of the application can also make the small droplet-formed material more uniformly dispersed, so as to improve the reaction efficiency and yield, so that the intermediate is converted into the final product. After the reaction liquid is extracted and heat-exchanged by the first circulating pump and the heat exchanger connected with the first intensification reactor, the temperature inside the multi-stage reactor is reduced, the generation of by-products is reduced, and the purity of the product is improved. Then the heat-exchanged reaction liquid enters the first intensification reactor through the first circulating pump feeding port, and the condensation reaction is strengthened again by the first intensification reactor, so that the product conversion rate is further improved.

[0018] The intensifier unit of the present application belongs to the prior art, although some are of the pneumatic type, some are of the hydraulic type, and some are of the gas-liquid linkage type. However, the differences between the types are mainly selected according to the different specific working conditions. In addition, the connection of the intensifier reactor and the reactor, as well as other equipment, including the connection structure and the connection position, is determined according to the structure of the intensifier reactor, which is not limited.

[0019] Preferably, as a further implementable scheme, it further includes a flash tank, a crude rectification tower, a trimethylolpropane refining tower, a recrystallization device and a filter connected in sequence, and the flash tank is connected with the multi-stage reactor.

[0020] The reaction liquid taken out through the first discharge port of the multi-stage reactor is pumped out by the first circulating pump, and then is heat-exchanged by the heat exchanger. The reaction liquid is then introduced into the flash tank through the two-way channel connected between the middle section of the multi-stage reactor and the flash tank, and is separated from most of the n-butyl aldehyde, formaldehyde and water in the reaction liquid through the flash tank. The separated n-butyl aldehyde, formaldehyde and water flow out from the top of the flash tank, and then are removed from most of the water by the flow divider connected with the flash tank. The remaining reaction liquid flows out from the discharge port at the bottom of the flash tank, and is mixed with the inert medium introduced through the inert medium inlet. The mixture is then introduced into the crude rectification tower through the inlet at the middle section of the crude rectification tower for rectification. After the rectification of the mixture in the crude rectification tower, the product trimethylolpropane and the by-product ditrimethylolpropane are taken out from the top of the crude rectification tower. The mixture of the product and the by-product is then introduced into the trimethylolpropane refining tower for further rectification. After the rectification of the trimethylolpropane refining tower, the product trimethylolpropane is taken out from the top of the trimethylolpropane refining tower, and is stored in the trimethylolpropane storage tank located above the trimethylolpropane refining tower. The by-product ditrimethylolpropane is taken out from the bottom of the trimethylolpropane refining tower, and is stored in the ditrimethylolpropane storage tank located below the trimethylolpropane refining tower. The mixture of the inert medium, water and sodium hydroxide taken out from the bottom of the crude rectification tower is then introduced into the recrystallization device through the discharge port at the bottom of the crude rectification tower. The inert medium is purified by the recrystallization device, and then the solid-liquid mixture obtained after the recrystallization is introduced into the filter for filtration. The filter residue is the inert medium, which can be reused in the crude rectification tower through the inert medium inlet after being cleaned. At this time, the filtrate is the sodium hydroxide aqueous solution and the by-product sodium formate. The sodium hydroxide aqueous solution obtained after the purification and desalination of the filtrate is introduced into the multi-stage reactor through the sodium hydroxide inlet connected with the filter above the multi-stage reactor for recycling.

[0021] The application also provides a reaction method of the high-efficiency synthesis system for preparing trimethylolpropane, comprising the following steps.

[0022] The n-butyl aldehyde, the catalyst and the metered formaldehyde are subjected to multi-stage reaction, and the condensation reaction is enhanced by the multi-stage reaction.

[0023] Preferably, as a further implementable scheme, the temperature of the multi-stage reaction is 40-50 DEG C, and the reaction time is 1-3 h.

[0024] The reaction of the high-efficiency synthesis system for preparing trimethylolpropane provided by the application improves the reaction efficiency and the product yield by adopting a multi-stage reactor, greatly reduces the temperature in the multi-stage reactor by an external circulation system, reduces the generation of by-products and improves the product purity. Since the n-butyl aldehyde and the formaldehyde aqueous solution are two incompatible systems, the phase boundary area between the two phases is increased by the use of the intensifier set, thereby improving the progress of the reaction process and the reaction yield. The use of the two-stage intensifier reactor can also ensure greater condensation of the n-butyl aldehyde and the formaldehyde, improve the conversion rate of the n-butyl aldehyde and reduce the generation of by-products, facilitating subsequent separation. The reaction liquid after complete reaction is cooled by the external circulation system of the multi-stage reactor. Since the condensation reaction is an exothermic reaction and the formaldehyde is used in excess, a large amount of heat is generated during the reaction process. In order to make the reaction proceed completely, the external circulation system is adopted, the excess formaldehyde is fully utilized and the excessive heat is removed in time, and the reaction system is fully mixed. The formaldehyde is continuously quantitatively supplemented by the metering pump in the process of continuous circulation, the reaction is stably maintained, the high conversion rate of the n-butyl aldehyde is ensured, and the viscosity is increased due to the increasing concentration of the formate during the rectification, which is not conducive to subsequent separation. Therefore, the reaction liquid is introduced into a flash tank for preliminary separation, the excess formaldehyde and water are evaporated into the circulation, then the inert medium is introduced into the crude rectification column. Since the inert medium has the characteristics of high boiling point, the by-product formate is separated in the crude rectification column. When the temperature reaches the melting point of the formate, the flowability is greatly improved and the viscosity is reduced, so that the viscosity of the liquid in the crude rectification column is low, and the normal operation of the crude rectification column is ensured. In the recrystallization device, the application uses water as a solvent and the inert medium, and the solubility of sodium hydroxide changes with the change of temperature, so that the sodium hydroxide is purified and separated. The separated sodium hydroxide can also be recycled after cleaning.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] (1) The high-efficiency synthesis system of the application can maximize the completion of the condensation reaction through the arrangement of multiple-stage intensified reactors and the application of intensified units, increase the contact area between raw materials through the intensified units, thereby improving the reaction rate and product yield, and remove the reaction heat in time through the external circulation system to accurately control the reaction temperature, reduce the generation of reaction by-products, and facilitate subsequent purification and separation.

[0027] (2) The high-efficiency synthesis method of trimethylolpropane provided by the application has simple operation, mild operation conditions, and high product yield. BRIEF DESCRIPTION OF DRAWINGS

[0028] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the application. Moreover, like reference numerals designate like parts throughout the several views in the drawings. In the drawings:

[0029] Fig. 1 is a structural schematic diagram of a high-efficiency synthesis system of trimethylolpropane according to the application;

[0030] Fig. 2 is a structural schematic diagram of a first intensified reactor according to the application;

[0031] Fig. 3 is a structural schematic diagram of a second intensified reactor according to the application.

[0032] In the drawings, the components represented by the reference numerals are listed as follows:

[0033] In the drawings, 1 is a n-butyl aldehyde feed inlet, 2 is a flow divider, 3 is a mixer, 4 is a metering pump, 5 is an inert medium feed inlet, 6 is a trimethylolpropane storage tank, 7 is a trimethylolpropane refining column, 8 is a recrystallization device, 9 is a filter, 10 is a double trimethylolpropane storage tank, 11 is a crude rectification column, 12 is a flash tank, 13 is a multi-stage reactor, 14 is a first intensified reactor, 15 is a sodium hydroxide feed inlet, 16 is a mixed liquid feed inlet, 17 is a second circulating pump, 18 is a first circulating pump, 19 is a heat exchanger, 20 is a second intensified reactor, 21 is a first circulating pump feed inlet, 22 is a first intensified unit, 23 is a first partition, 24 is a formaldehyde feed inlet, 25 is a second intensified unit, 26 is a second partition, 27 is a metering pump feed inlet, and 28 is a first discharge port. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described clearly and completely in combination with the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, not all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. The specific conditions are not specified in the embodiments, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0035] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. In order to more clearly set forth the technical solutions in the present application, the following will be described in the form of specific embodiments.

[0037] Example 1

[0038] Referring to FIG. 1, a high-efficiency synthesis system for preparing trimethylolpropane includes 1. n-Butyl aldehyde feed inlet; 2. Splitter; 3. Mixer; 4. Metering pump; 5. Inert medium feed inlet; 6. Trimethylolpropane storage tank; 7. Trimethylolpropane refining tower; 8. Recrystallization device; 9. Filter; 10. Double trimethylolpropane storage tank; 11. Crude rectification tower; 12. Flash tank; 13. Multistage reactor; 14. First intensifier reactor; 15. Sodium hydroxide feed inlet; 16. Mixed liquid feed inlet; 17. Second circulating pump; 18. First circulating pump; 19. Heat exchanger; 20. Second intensifier reactor; 21. First circulating pump feed inlet; 22. First intensifier unit; 23. First partition; 24. Formaldehyde feed inlet; 25. Second intensifier unit; 26. Second partition; 27. Metering pump feed inlet; 28. First discharge port.

[0039] In the reaction process of the high-efficiency synthesis for preparing trimethylolpropane, the raw material n-butyl aldehyde is fed into the second intensifier reactor 20 in the multistage reactor 13 at a dosage of 196 kg / h with the catalyst sodium hydroxide aqueous solution, and then the formaldehyde is metered by the metering pump 4 and fed into the mixer 3 at 120 kg / h through the metering pump feed inlet 27, and then fed into the second intensifier reactor 20 through the formaldehyde feed inlet 24 in the second intensifier reactor 20. The raw material is processed into liquid droplets by the second intensifier unit 25 in the second intensifier reactor 20, and then the material processed into liquid droplets is uniformly dispersed by the second partition 26 in the second intensifier reactor 20. Then, the second circulating pump 17 extracts 30% of the reaction liquid volume in the multistage reactor 13, which is heat-exchanged by the heat exchanger connected to the second circulating pump 17. After being mixed with the methanol added by the metering pump 4 through the mixer 3, the heat-exchanged reaction liquid is returned to the reaction system through the mixed liquid feed inlet 16 above the multistage reactor 13, and the temperature in the multistage reactor 13 is maintained at 40-50°C.

[0040] The reaction liquid processed by the second intensifier reactor 20 gradually drops into the first intensifier reactor 14, and the first intensifier unit 23 in the first intensifier reactor 14 processes the material into liquid droplets again, and then the first partition 23 in the first intensifier reactor 14 disperses the liquid droplet material more uniformly. During the reaction in the first intensifier reactor, the first circulating pump 18 extracts 30% of the reaction liquid volume, which is heat-exchanged by the heat exchanger 19 and then fed into the multistage reactor 13 through the first circulating pump feed inlet 21, and then reacts again in the first intensifier reactor 14.

[0041] After the reaction is completed, the reaction liquid is taken out from the first outlet 28 by the first circulating pump 21, and then enters the flash tank 12 through the two-way channel in the middle of the multi-stage reactor. Most of the n-butyl aldehyde, formaldehyde and water in the reaction liquid are separated in the flash tank 12. The separated n-butyl aldehyde, formaldehyde and water flow into the flow divider 2 from the top of the flash tank. After a large amount of water is separated by the flow divider 2, the n-butyl aldehyde and formaldehyde enter the multi-stage reactor 13 from the mixed liquid inlet 16 above the multi-stage reactor 13. The remaining reaction liquid flows out from the bottom of the flash tank 12, mixes with the inert medium introduced through the inert medium inlet 5, and then enters the crude rectification tower 11 through the inlet in the middle of the crude rectification tower 11. The product trimethylolpropane and the by-product ditrimethylolpropane are mixed in the top of the crude rectification tower 11, and then enter the trimethylolpropane refining tower 7 through the inlet in the middle of the trimethylolpropane refining tower 7. Trimethylolpropane is taken out from the top of the trimethylolpropane refining tower 7, and then stored in the trimethylolpropane storage tank 6. The by-product ditrimethylolpropane is taken out from the bottom of the trimethylolpropane refining tower 7, and then stored in the ditrimethylolpropane storage tank 10. The mixture of inert medium, water and sodium hydroxide solution in the bottom of the crude rectification tower 11 flows into the recrystallization device 8 to purify the inert medium. The solid-liquid mixture after recrystallization is filtered by the filter 9. The filter residue is the inert medium, which can be recycled into the multi-stage reactor 13 through the inert medium inlet 5 after cleaning. The filtrate is the mixture of sodium hydroxide solution and sodium formate, which can be recycled into the reactor through the sodium hydroxide inlet 15 above the multi-stage reactor 13 after desalination and purification.

[0042] Example 2

[0043] The difference between this example and Example 1 is that the second strengthening unit in the second strengthening reactor 20 is arranged above the second partition.

[0044] Example 3

[0045] The difference between this example and Example 1 is that the first strengthening unit in the first strengthening reactor 14 is arranged above the first partition.

[0046] Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that the second strengthening reactor 20 is not arranged.

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that the second partition is not arranged in the second strengthening reactor 20.

[0050] Comparative Example 3

[0051] The difference between the present comparative example and Example 1 is that the second intensifying unit is not provided inside the second intensifying reactor 20.

[0052] Comparative Example 4

[0053] The difference between the present comparative example and Example 1 is that the first intensifying reactor 14 is not provided.

[0054] Comparative Example 5

[0055] The difference between the present comparative example and Example 1 is that the first partition is not provided inside the first intensifying reactor 14.

[0056] Comparative Example 6

[0057] The difference between the present comparative example and Example 1 is that the first intensifying unit is not provided in the first intensifying reactor.

[0058] Comparative Example 7

[0059] The difference between the present comparative example and Example 1 is that the second circulating pump 17 and the heat exchanger 19 are not provided.

[0060] Comparative Example 8

[0061] The difference between the present comparative example and Example 1 is that the first circulating pump 18 and the heat exchanger 19 are not provided.

[0062] Comparative Example 9

[0063] The difference between the present comparative example and Example 1 is that the first circulating pump 18 and the second circulating pump 20 and the corresponding heat exchangers are not provided.

[0064] Table 1 is the product yield and conversion rate of the present application and the comparative examples:

[0065] The yield calculation formula is: yield = reacted material amount / total feed

[0066] The conversion rate calculation formula is: conversion rate = product amount generated by reaction / theoretical product amount generated

[0067] It can be known from the comparative example 1-2 and the comparative example 1-3 that the second intensification unit and the second partition plate in the second intensification reactor are position-limited, and only when they are arranged in the position provided by the application, the product yield and conversion rate are the highest, because when the raw material enters the multi-stage reactor, it is treated by the second intensification unit, so that the material is broken into the form of liquid droplets, and then because the material treated by the second intensification unit is distributed unevenly in the reactor, the unevenly distributed liquid droplets will affect the reaction rate and product yield to some extent, therefore, the application arranges the second partition plate in the second intensification reactor, so that the material in the form of liquid droplets is more evenly distributed, thereby improving the reaction rate and product yield, and after being treated by the second intensification reactor, the material is in the form of small droplets during the descending process in the reactor, thereby increasing the contact area between the reactants again and improving the conversion rate. The application enhances the phase interface area between the reaction raw materials by arranging the second intensification reactor, because the n-butyl aldehyde and the formaldehyde aqueous solution used as the raw material are a two-phase system that is not miscible with each other, therefore, in the traditional trimethylolpropane, the reaction is not complete due to the immiscibility between the two, therefore, the application arranges the second intensification reactor at the center of the multi-stage reactor, thereby increasing the phase interface area between the n-butyl aldehyde and the formaldehyde, so that the formaldehyde and the n-butyl aldehyde can be mixed for a longer time, increasing the reaction time between the two, thereby improving the progress and yield of the reaction process.

[0068] It can be known from the comparative example 1, the example 3 and the comparative example 4-6 that the first intensification unit and the first partition plate in the first intensification reactor are position-limited, because the reaction liquid treated by the preliminary reaction of the second intensification reactor is in the form of liquid droplets and descends to the first intensification reactor arranged at the bottom of the multi-stage reactor, the condensation reaction is enhanced by the first intensification reactor at the bottom of the multi-stage reactor, so that the intermediate is converted into the final product, and the liquid droplets are more evenly distributed after passing through the first partition plate arranged in the first intensification reactor, the condensation reaction is enhanced by the first intensification unit arranged in the first intensification reactor, thereby improving the reaction efficiency and yield, so that the intermediate is converted into the final product.

[0069] It can be known from the comparison between the example 1 and the comparative examples 7-9 that the external circulation system provided in the application is extremely important, because the reaction temperature in the multi-stage reactor is high due to the exothermic reaction of the condensation reaction and the excessive use of formaldehyde during the reaction, in order to make the reaction complete, the external circulation system is used, the excessive formaldehyde is fully utilized and the excessive heat is removed in time through the circulation, and the reaction system is fully mixed, in the reaction process of the second intensifier reactor, 30% of the reaction liquid is extracted by the second circulation pump, heat exchange is carried out through the heat exchanger connected with the second circulation pump, the reaction temperature in the multi-stage reactor is greatly reduced, the generation of by-products is reduced, after the heat exchange, the n-butyl aldehyde is quantitatively added by the metering pump, mixed by the mixer and then enters the second intensifier reactor through the formaldehyde feeding port, and is fully mixed with the n-butyl aldehyde and the sodium hydroxide aqueous solution entering through the n-butyl aldehyde feeding port above the multi-stage reactor, through such an external circulation system, the temperature in the multi-stage reactor can be kept at 40-50℃ all the time. After the reaction liquid is extracted and heat exchanged by the first circulation pump and the heat exchanger connected with the first intensifier reactor, the temperature in the multi-stage reactor is reduced, the generation of by-products is reduced and the purity of the product is improved, and then the heat-exchanged reaction liquid enters the multi-stage reactor through the bidirectional channel in the middle of the multi-stage reactor, the condensation reaction is enhanced by the first intensifier reactor again, and the conversion rate of the product is further improved.

[0070] Therefore, the high-efficiency synthesis system of trimethylolpropane provided in the application can make the reaction more complete and obtain higher trimethylolpropane yield by providing multiple intensifier reactors and using the intensifier unit in the reactor to increase the mass transfer area between the two phases of formaldehyde and n-butyl aldehyde, increase the turbulence and mixed flow between the two phases, providing two intensifier reactors in the multi-stage reactor; in addition, the circulation-heat exchange system is provided outside the multi-stage reactor, because the formaldehyde in the reaction system is excessive and the reaction is an exothermic process, the excessive formaldehyde is fully utilized and the reaction heat is removed in time through the circulation-heat exchange system, the reaction system is more uniformly mixed, the reaction is more complete, the reaction temperature can be better controlled, and more by-products can be avoided.

[0071] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the above examples, those skilled in the art should understand that the technical solutions described in the above examples can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A high efficiency synthesis system for preparing trimethylolpropane, characterized by, The application relates to a multi-stage reactor internally vertically provided with multiple reinforced reactors which are uniformly arranged from top to bottom, wherein a n-butyl aldehyde feeding port is arranged at the top of the multi-stage reactor and is connected to the reinforced reactors; a mixed liquid feeding port and a sodium hydroxide feeding port are arranged at the two sides of the top of the multi-stage reactor; and a first discharging port is arranged at the bottom of the multi-stage reactor.

2. The efficient synthesis system of claim 1, wherein, The number of the reinforced reactors is two, the first reinforced reactor is arranged at the bottom of the multi-stage reactor, and the second reinforced reactor is arranged at the center of the multi-stage reactor.

3. The efficient synthesis system of claim 2, wherein, The first reinforced reactor is internally provided with a first reinforced unit and a first partition plate for increasing the phase boundary area between two phases, and the first partition plate is arranged directly below the first reinforced unit.

4. The efficient synthesis system of claim 2, wherein, A first circulating pump feeding port is arranged above the first reinforced unit and is connected to the first reinforced unit, and the first circulating pump is connected to the first reinforced unit through the first circulating pump feeding port.

5. The efficient synthesis system of claim 2, wherein, The second reinforced reactor is internally provided with a second reinforced unit and a second partition plate, and the second reinforced unit is arranged directly below the second partition plate.

6. The efficient synthesis system of claim 5, wherein, A formaldehyde feeding port is arranged above the second reinforced unit and is connected to the second reinforced unit, a second circulating pump is connected to the second reinforced unit through the formaldehyde feeding port, a heat exchanger and a mixer are sequentially connected between the second circulating pump and the second reinforced unit, a metering pump feeding port is arranged between the heat exchanger and the mixer, and a metering pump is connected to the mixer through the metering pump feeding port.

7. The efficient synthesis system of claim 1, wherein, The application further comprises a flash tank, a crude rectification tower, a trimethylolpropane refining tower, a recrystallization device and a filter which are sequentially connected and connected to the multi-stage reactor.

8. A method for the reaction performed by the high-efficiency synthesis system for preparing trimethylolpropane according to any one of claims 1 to 7, characterized by, The application comprises the following steps: The n-butyl aldehyde, a catalyst and the metered formaldehyde are subjected to multi-stage reaction, and the condensed product is obtained after the multi-stage reaction.

9. The method of synthesis of claim 8, wherein, The temperature of the multi-stage reaction is 40-50 DEG C, and the reaction time is 1-3 hours.

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