A device for continuous reaction of alkylation of m-cresol and / or p-cresol
Through the combination of the tube reactor and the water evaporation and heat removal cycle module, the heat transfer efficiency and equipment production capacity of the intermediate cresol and p-cresol are solved in the prior art, and the high efficiency and safety are achieved. Continuous production and efficient utilization of isobutene.
Patent Information
- Application Number
- CN202110667539.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-06-16
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2041-06-16
AI Technical Summary
In the prior art, the separation and alkylation reaction of intermediate cresol and p-cresol have problems such as low heat transfer efficiency, low isobutene conversion rate, limited equipment production capacity and difficult safety control, especially it is difficult to provide sufficient replacement. Thermal area and reaction heat management.
The coupling device of the tube-type reaction module, the tube-type reactor water evaporation and heat removal cycle module and the reaction rectification module is adopted, and the high heat transfer coefficient of the tube-type reactor and the temperature control capability of the water evaporation and heat removal cycle module are used. The alkylation reaction is efficiently carried out, and the equilibrium state of the reversible reaction is broken through the reaction rectification module, thereby improving the reaction rate and selectivity.
It realizes efficient continuous reactions of m-cresol and p-cresol alkylation, improves the production capacity of a single equipment, reduces energy consumption and equipment investment, ensures stable product quality and production safety, and does not require isobutene recycling facilities.
Smart Images
Figure CN113248349B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of separation of meta- and para-cresol, and also belongs to the technical field of chemical reaction synthesis of (mono- and / or di-)tert-butylcresol by alkylation of (meta- and or para-)cresol and isobutylene, and specifically relates to a device for continuous alkylation reaction of meta- and / or para-cresol. Background Art
[0002] Cresol is a widely used organic chemical intermediate. p-Cresol is the raw material for making antioxidant 2,6-di-tert-butyl-p-cresol and rubber antioxidant. It can be used to make cresol-formaldehyde resin and plasticizer in the plastic industry. It is used as a disinfectant in medicine and can also be used as a raw material for pesticides and dyes. m-Cresol is an important raw material for synthesizing organic intermediates. At the same time, it also has important applications in color film developers, synthetic resins, adhesives, etc. The boiling points of m-Cresol and p-Cresol are very close, and it is difficult to separate them directly by distillation. After isobutylene alkylation, mono-tert-butyl (m- / p-) cresol and di-tert-butyl (m- / p-) cresol are generated. The boiling point difference of each component becomes larger, which makes it easier to separate. Isobutylene alkylation is not only the main process for separating m-p-cresol mixtures, but also the main process for synthesizing mono-tert-butyl (m- or p-) cresol and di-tert-butyl (m- or p-) cresol. At present, domestic separation of m-cresol or synthesis of tert-butyl (m- or p-)cresol mostly adopts intermittent reactors, which have small output, many operators, high energy consumption, low efficiency and great difficulty in safe production control.
[0003] Chinese patent CN104496758A discloses a method for continuous alkylation of m-cresol and p-cresol, which uses 6 alkylation kettles connected in series to carry out continuous alkylation reaction. Although the reaction device provided in the patent can carry out continuous production, the alkylation reactors used in the reaction device are all kettle-type. For alkylation reactions with large reaction heat, it is difficult to provide sufficient heat exchange area, the production capacity of a single device is limited, the reaction time is long, and the number of devices is large; at the same time, the alkylation reaction is a reversible reaction. Although there are 6 kettle reactors connected in series, the reaction limit can only be to carry out the reaction to the reaction equilibrium state, and in order to increase the reaction rate in the later stage, excess isobutylene must be used; but the excess isobutylene and the isobutylene that is not reacted due to the reaction equilibrium limit need to increase the isobutylene recovery and reuse equipment to improve the utilization rate of the material.
[0004] Chinese patent CN111302904A discloses an alkylation continuous reaction device for BHT production. A tower reactor is used in the alkylation reaction process. The reaction device provided in the patent is also difficult to provide sufficient heat exchange area for alkylation reactions with large reaction heat, and the production capacity of a single device is limited. At the same time, the reaction limit can only carry out the reaction to the reaction equilibrium state. Excess isobutylene and isobutylene that has not reacted due to the reaction equilibrium limit also need to increase isobutylene recovery and reuse equipment to improve material utilization. Summary of the invention
[0005] The purpose of the present invention is to provide a device for continuous alkylation of m-cresol and / or p-cresol, in view of the fact that the existing technology for separating m-cresol and p-cresol mostly adopts an intermittent reactor, and in the process of alkylation reaction with isobutylene, the alkylating agent isobutylene cannot fully contact with the mixed phenol (a mixture of m-cresol and p-cresol), the isobutylene conversion rate is low, and the heat transfer efficiency is low. The device couples a shell-and-tube reaction module, a shell-and-tube reactor water evaporation heat removal circulation module and a reaction distillation module. In the process of alkylation reaction, the shell-and-tube reactor has a large heat transfer area per unit volume (the heat transfer area per unit volume of a conventional kettle reactor is about 1-8 m 2 The heat transfer area per unit volume of conventional shell-and-tube reactors can reach 70m 2 Around), high heat transfer coefficient (when both sides are water and both are liquid phase, the total heat transfer coefficient of the kettle reactor with stirring and coil is 700W / m 2 / K, the total heat transfer coefficient of the kettle reactor without stirring and coil is smaller, while the total heat transfer coefficient of the shell-and-tube reactor can reach 2000W / m 2 / K or so), and the shell-and-tube reactor uses a water evaporation heat removal circulation module. In addition to the high heat transfer coefficient, under a given water evaporation pressure, the evaporation temperature is constant, and the reaction temperature distribution inside the shell-and-tube reactor is more uniform. By adjusting the water evaporation pressure, the heat transfer temperature difference on both sides of the shell-and-tube reactor can be changed, and then the reaction temperature can be adjusted and controlled. The dynamic response of the reactor heat removal control is fast and the effect is good. The shell-and-tube reaction module and the shell-and-tube reactor water evaporation heat removal circulation module are used together to meet the requirements of timely heat removal of strong exothermic reactions and avoid excessive local temperatures. The reaction temperature control effect is good and the production capacity of a single device is large; through the reaction distillation module, the equilibrium state limitation of the reversible reaction is broken, the reaction rate is fast, the reaction selectivity is good, the utilization rate of isobutylene raw materials is high, and there is no need to set up isobutylene recovery facilities; continuous production can be achieved, the degree of automation is high, the structure of the entire device is simple, and the production efficiency of the entire alkylation reaction is improved. It has the advantages of low equipment investment, stable product quality, and low energy consumption.
[0006] Another object of the present invention is to use the above-mentioned device to carry out a continuous alkylation reaction with isobutylene as an alkylating agent and m-cresol and / or p-cresol (cresol) as raw materials.
[0007] The technical solution adopted by the present invention is as follows:
[0008] A device for continuous alkylation reaction of m-cresol and / or p-cresol, comprising a tubular reaction module, a tubular reactor water evaporation heat removal circulation module and a reaction distillation module:
[0009] The shell-and-tube reaction module includes a preheater, a high-efficiency mixer, a shell-and-tube reactor and a pressure stabilizing tank. The preheater is connected to the high-efficiency mixer, the high-efficiency mixer is connected to the feed port of the shell-and-tube reactor, the discharge port of the shell-and-tube reactor is connected to the pressure stabilizing tank, and the pressure stabilizing tank is provided with a pressure step-by-step regulating system.
[0010] The water evaporation heat removal circulation module of the shell and tube reactor comprises a water vapor condenser cooler, a water vapor condensate tank, a vacuum pump inlet condenser cooler and a vacuum pump, the water vapor outlet of the shell and tube reactor is connected to the inlet of the water vapor condenser cooler, the outlet of the water vapor condenser cooler is connected to the inlet I of the water vapor condensate tank, the outlet I of the steam condensate tank is connected to the water inlet of the shell and tube reactor, the outlet II of the water vapor condensate tank is connected to the inlet of the vacuum pump inlet condenser cooler, the outlet I of the vacuum pump inlet condenser cooler is connected to the inlet II of the water vapor condensate tank, and the outlet II of the vacuum pump inlet condenser cooler is connected to the vacuum pump;
[0011] The reaction distillation module includes a tower feed vaporizer, a reaction temperature control device for the reaction distillation tower and a reaction distillation tower. The pressure stabilizing tank is connected to the inlet of the tower feed vaporizer. A pressure reducing valve is arranged on the pipeline between the pressure stabilizing tank and the tower feed vaporizer. The gas phase discharge port of the tower feed vaporizer is connected to the lower part of the reaction distillation tower. The liquid phase discharge port of the tower feed vaporizer is connected to the inlet of the reaction temperature control device of the reaction distillation tower. The outlet of the reaction temperature control device of the reaction distillation tower is connected to the upper part of the reaction distillation tower. The reaction distillation tower is provided with a distillation section, a reaction section and a stripping section in sequence from top to bottom.
[0012] For this device, the number of tubular reactors can be selected according to actual needs. For example, according to the restrictions on raw materials and products, the number of tubular reactors can be 1 or multiple. Multiple here means more than 2, but not limited to 2, 3, 4, 5, 10 or 15. When the number of tubular reactors is multiple, that is, more than 2, the connection between the tubular reactors is in series and / or in parallel. Preferably, the number of tubular reactors is 1 to 3. For the tubular reactors in series, the feeding method of the alkylating agent isobutylene can be added in full before the first tubular reactor, or it can be added separately, that is, added before each tubular reactor. When added separately, the amount of isobutylene at each addition point can be the same or different. Generally, the tubular reactors are selected to be fed in decreasing order one by one. For example, when three series-connected shell-and-tube reactors are provided in the device, liquid isobutylene can be added at three locations respectively: 65% of the total amount is added before the first shell-and-tube reactor, 25% of the total amount is added before the second shell-and-tube reactor, and 10% of the total amount is added before the third shell-and-tube reactor.
[0013] In the device, a pressure regulating system is provided on the pressure stabilizing tank. The specific pressure regulating system can adopt a pressure control device commonly used in the prior art to control the reaction pressure of the shell-and-tube reactor.
[0014] The number of high-efficiency mixers can be selected according to actual needs, for example, the number of high-efficiency mixers is 1 or more, where more than 2 means more than 2, and can be but not limited to 2, 3, 4, 5, 10 or 15. Generally, when there are multiple shell-and-tube reactors, each shell-and-tube reactor can be equipped with a high-efficiency mixer, or other similar equipment that plays a role in dispersing and mixing uniformly.
[0015] For the present invention, the shell and tube reactor can select the shell and tube reactor commonly used in the market, and its specifications are not strictly limited. Homogeneous reaction can be carried out, and heterogeneous reaction can also be carried out, for example, liquid-liquid phase reaction or gas-liquid phase reaction. In a preferred embodiment, the catalyst for catalyzing the alkylation reaction of meta-cresol and / or p-cresol and isobutylene is loaded in the tube or between the tubes of the shell and tube reactor. As for the catalyst, a homogeneous catalyst can be selected, and a heterogeneous catalyst can also be selected, which can be selected according to actual needs. When the catalyst is a heterogeneous solid catalyst, it can be loaded in the tube of the shell and tube reactor, and it can also be loaded between the tubes of the shell and tube reactor.
[0016] At present, when isobutylene is used as an alkylating agent and m-cresol and / or p-cresol (cresol) are used as raw materials for continuous alkylation reaction, the reaction temperature is generally low, not higher than 100° C. For example, the reaction temperature selected in the present invention is 50-90° C. In view of the heat transfer problem that is common in the alkylation reaction due to a large amount of heat release, water cooling is generally used, but the inlet and outlet temperature difference of the cooling water is limited, the heat transfer coefficient is not high, the heat transfer effect is poor, and the temperature in each reaction device (for example, a shell and tube reactor) cannot be quickly reduced to the reaction temperature. If the temperature is too high, side reactions are likely to occur, resulting in a decrease in the yield and purity of the product, which seriously limits the production efficiency of each reaction device.
[0017] The present invention adopts a tubular reactor water evaporation heat removal circulation module. In addition to the high heat transfer coefficient, under a given water evaporation pressure, the evaporation temperature is constant, the reaction temperature distribution inside the tubular reactor is more uniform, and the heat transfer temperature difference on both sides of the tubular reactor can be changed by adjusting the water evaporation pressure, thereby adjusting and controlling the reaction temperature, and the reaction heat generated in the tubular reactor can be withdrawn in time, so that the dynamic response of the reactor heat removal control is fast and the effect is good. In the process of carrying out the alkylation reaction, the vacuum pump is turned on to control the pressure in the water evaporation heat removal circulation module to be 7~30kpa (a), and deoxygenated water is introduced into the tubular reactor so that the deoxygenated water entering the tubular reactor absorbs heat and performs negative pressure evaporation. The water vapor generated after the negative pressure evaporation enters the water vapor condensation cooler from the steam outlet of the tubular reactor for condensation, and the condensed water obtained after condensation enters the water vapor condensation tank, and the condensed water in the water vapor condensation tank is then introduced into the tubular reactor to continue absorbing heat and perform negative pressure evaporation. Since the temperature of the alkylation reaction is generally lower than the boiling point of water at normal pressure (100° C.), the water evaporation pressure in the water evaporation and heat removal circulation module of the shell-and-tube reactor in the present invention is negative pressure. The vacuum pump is first turned on to evacuate the water evaporation and heat removal circulation module, and the pressure is controlled to be 7-30 kPa(a). Preferably, the pressure is controlled to be 15-20 kPa(a). The air leaked into the circulation module entrains saturated water vapor and is pumped to the condenser cooler at the inlet of the vacuum pump for condensation and cooling. The condensed water is discharged into the water vapor condensate tank through a pipeline; the cooled air enters the vacuum pump and is directly discharged from the air outlet of the vacuum pump.
[0018] In a preferred embodiment, the preheater includes a preheater I for preheating m-cresol and / or p-cresol and a preheater II for preheating isobutylene; the shell-and-tube reactor includes a shell-and-tube reactor I, a shell-and-tube reactor II and a shell-and-tube reactor III connected in series in sequence; the high-efficiency mixer includes a high-efficiency mixer I, a high-efficiency mixer II and a high-efficiency mixer III;
[0019] The outlet of the preheater II is connected to the inlet I of the high-efficiency mixer I, the inlet I of the high-efficiency mixer II and the inlet I of the high-efficiency mixer III respectively; the outlet of the preheater I is connected to the inlet II of the high-efficiency mixer I, the outlet of the high-efficiency mixer I is connected to the feed port of the shell-and-tube reactor I, the discharge port of the shell-and-tube reactor I is connected to the inlet II of the high-efficiency mixer II, the outlet of the high-efficiency mixer II is connected to the feed port of the shell-and-tube reactor II, the discharge port of the shell-and-tube reactor II is connected to the inlet II of the high-efficiency mixer III, the outlet of the high-efficiency mixer III is connected to the feed port of the shell-and-tube reactor III, and the discharge port of the shell-and-tube reactor III is connected to the inlet of the pressure-surge tank.
[0020] Reactive distillation has significant advantages due to the mutual influence of distillation operation and chemical reaction, such as improving the conversion rate and selectivity of reactants, reducing equipment investment costs and operating costs, compact equipment and less space occupation, and the catalyst filling layer plays a role in accelerating the chemical reaction rate and mass transfer, etc. However, the use of reactive distillation must also meet some basic requirements, such as the chemical reaction must be carried out in the liquid phase, the reaction temperature of the main reaction under the operating system pressure is close to the bubble point temperature of the target product, and the main reaction cannot be a strong endothermic reaction, etc. The main reaction temperature in the present invention is 50~90℃, the normal pressure boiling point of the raw material m-p-cresol is about 202℃, the normal pressure boiling point of the mono-tert-butyl product is about 230~240℃, and the normal pressure boiling point of the di-tert-butyl product is about 265~295℃; even if the reactive distillation tower is maintained at an absolute pressure of 5kpa, the boiling point of m-p-cresol also reaches 114℃, and the boiling point of the tert-butyl product is higher. Therefore, industrial devices cannot select a suitable operating pressure of the reaction distillation tower so that the reaction temperature of the main reaction is close to the bubble point temperature of the target product, and conventional reaction distillation towers cannot be applied to the present invention.
[0021] The reaction distillation module in the device includes a tower feed vaporizer, a reaction distillation tower reaction temperature control device and a reaction distillation tower, wherein the reaction distillation tower is provided with a distillation section, a reaction section and a stripping section in sequence from top to bottom, and there is no need to set up a tower top condenser and a tower kettle reboiler.
[0022] The internals of the rectifying section are fillers or trays, and the specific rectifying section can be one or more sections. The rectifying section is multi-section, which means that it includes more than two rectifying sections. The tower of the reaction section is filled with a solid catalyst, and the alkylation reaction and the alkylation distillation are coupled to improve the conversion rate of the reaction raw materials and the reaction effect. The reaction section can also be one or more sections, and the reaction section is multi-section, which means that it includes more than two reaction sections. The internals of the stripping section are fillers or trays, and the specific stripping section can be one or more sections. The stripping section is multi-section, which means that it includes more than two stripping sections.
[0023] A pressure reducing valve is provided on the pipeline between the pressure stabilizing tank and the tower feed vaporizer. During the process of transferring the material from the pressure stabilizing tank to the tower feed vaporizer, the pressure after the valve is controlled to be 5~20kpa(a) through the pressure reducing valve. Preferably, the control pressure is 8~12kpa(a).
[0024] For this device, the material in the pressure-surge tank first enters the tower feed vaporizer, and the material is partially vaporized under the condition of 110~150℃, and gaseous material and liquid material are formed in the upper and lower parts of the tower feed vaporizer respectively. The gaseous material is mainly isobutylene, diisobutylene, part of trimerized isobutylene and cresol, and the liquid material is mainly mono-tert-butyl cresol, di-tert-butyl cresol, part of trimerized isobutylene and cresol; the liquid material is transferred from the liquid phase discharge port provided on the tower feed vaporizer to the reaction temperature control device of the reaction distillation tower (used to control the temperature of the liquid phase material, and a heat exchanger that can control the temperature of the liquid phase material in the prior art can be selected) for temperature adjustment, and the temperature-adjusted liquid phase material enters the reaction distillation tower through the pipeline from the upper part of the reaction distillation tower; the gas phase material enters the reaction distillation tower from the gas phase discharge port provided on the tower feed vaporizer through the pipeline from the lower part of the reaction distillation tower, and contacts and reacts with the liquid phase material entering the reaction distillation tower in the reaction section in reverse direction.
[0025] In order to achieve the purpose of the present invention and improve the reaction rate and selectivity of the materials after the reaction in the shell-and-tube reactor, the present invention modifies the structure and process of the reaction distillation tower, eliminates the top condenser and the kettle reboiler of the reaction distillation tower; utilizes the characteristics of high light component content and low vaporization temperature in the feed of the reaction distillation tower to partially vaporize the feed, and provide stable gas phase and liquid phase logistics for the reaction distillation tower, the gas phase is rich in isobutylene, and the liquid phase is cresol and alkylation products, the gas phase enters from the bottom of the reaction distillation tower, and the liquid phase enters from the top of the reaction distillation tower; the temperature of the gas phase gradually decreases from bottom to top, and the temperature of the liquid phase gradually increases from top to bottom, and the upper liquid phase feed temperature of the reaction distillation tower is adjusted by the reaction temperature control device of the reaction distillation tower, and then the temperature of the reaction section is controlled, so that the liquid phase temperature of the reaction section is close to the main reaction temperature, thereby realizing the coupled operation of reaction and distillation.
[0026] The present invention also provides a method for carrying out a continuous alkylation reaction using isobutylene as an alkylating agent and m-cresol and / or p-cresol (cresol) as raw materials using the above-mentioned device, which comprises the following steps:
[0027] (1) The preheated m-cresol and / or p-cresol and isobutylene are uniformly mixed in the high-efficiency mixer, and the obtained mixed material is introduced into the shell-and-tube reactor through the feed port of the shell-and-tube reactor through a pipeline, and an alkylation reaction is carried out at a temperature of 50-90° C. and a pressure of 6-14 barg. After the reaction is completed, the material obtained is transferred from the discharge port of the shell-and-tube reactor to a pressure-regulating tank through a pipeline; during the alkylation reaction, deoxygenated water is introduced into the shell-and-tube reactor, and the pressure in the water evaporation and heat removal circulation module of the shell-and-tube reactor is controlled to be 7-30 kPa (a), and the water vapor generated after negative pressure evaporation enters the water vapor condensation cooler from the water vapor outlet of the shell-and-tube reactor for condensation, and the condensed water obtained after condensation enters the water vapor condensation tank, and the condensed water in the water vapor condensation tank is then introduced into the shell-and-tube reactor to continue absorbing heat for negative pressure evaporation and heat removal;
[0028] (2) Open the pressure reducing valve, and under the condition that the pressure after the control valve is 5~20kpa(a), the material in the pressure stabilizing tank is passed into the tower feed vaporizer, and the material is partially vaporized at a temperature of 110~150°C, and gaseous materials and liquid materials are formed at the upper and lower parts of the tower feed vaporizer respectively. The liquid material is transferred from the liquid phase discharge port provided on the tower feed vaporizer to the reaction temperature control device of the reaction distillation tower for temperature adjustment. The liquid material with adjusted temperature enters the reaction distillation tower through the pipeline from the upper part of the reaction distillation tower; the gaseous material enters the reaction distillation tower through the gas phase discharge port provided on the tower feed vaporizer through the pipeline from the lower part of the reaction distillation tower, and reacts with the liquid material entering the reaction distillation tower in the reaction section. The reaction temperature is 50~90°C, and the reaction pressure is 5~20kpa(a). The gaseous material not participating in the reaction is extracted from the top of the tower, and the target product is extracted from the bottom of the tower.
[0029] In a preferred embodiment, in step (1), the temperature of the alkylation reaction is 60-80°C.
[0030] In the present device, the pressure range regulating system is opened to control the pressure of the alkylation reaction. Furthermore, the pressure of the alkylation reaction is 8-10 barg.
[0031] Furthermore, the vacuum pump is turned on to evacuate the water, and the pressure in the water evaporation and heat removal circulation module of the shell-and-tube reactor is 15-20 kPa(a).
[0032] In a preferred embodiment, in step (2), after the pressure reducing valve is opened, the pressure is controlled to be 8-12 kPa(a).
[0033] Furthermore, when the material is vaporized in the vaporizer, the temperature of the material in the vaporizer is controlled to be 120-140°C.
[0034] Furthermore, when the reaction is carried out in the reaction section, the reaction temperature is 60-80° C. and the reaction pressure is 8-12 kpa(a).
[0035] In a preferred embodiment, the number of the tubular reactors is 3, including tubular reactor I, tubular reactor II and tubular reactor III connected in series; a catalyst for catalyzing the alkylation reaction of m-cresol and / or p-cresol with isobutylene is loaded in or between the tubes of each tubular reactor. The number of the high-efficiency mixers is 1 or more.
[0036] The internals of the rectifying section are fillers or trays. Specifically, the rectifying section can be one or more sections. The rectifying section being multi-section means that it includes more than two rectifying sections. The tower of the reaction section is filled with a solid catalyst, which can catalyze the unparticipated reaction raw materials in the materials entering the reaction distillation tower to continue to react, thereby improving the conversion rate of the reaction raw materials and improving the reaction effect. The reaction section can also be one or more sections. The reaction section being multi-section means that it includes more than two reaction sections. The internals of the stripping section are fillers or trays. Specifically, the stripping section can be one or more sections. The stripping section being multi-section means that it includes more than two stripping sections.
[0037] The beneficial effects of the present invention are:
[0038] The present invention provides a device for continuous alkylation reaction of m-cresol and / or p-cresol, wherein a tubular reaction module, a tubular reactor water evaporation heat removal circulation module and a reaction distillation module are coupled. In the process of the alkylation reaction, the tubular reactor has a large heat transfer area per unit volume and a high heat transfer coefficient, and the water evaporation heat removal circulation module has the advantages of uniform temperature control and fast dynamic response, so that the requirements of timely heat removal and avoiding local overheating of a strong exothermic reaction can be met, the reaction temperature control effect is good, and the production capacity of a single device is large; through the reaction distillation module, the equilibrium state limitation of the reversible reaction is broken, the reaction rate is fast, the selectivity is good, the utilization rate of isobutylene raw materials is high, and no isobutylene recovery facilities need to be set up; continuous production can be achieved, the degree of automation is high, the structure of the entire device is simple, the production efficiency of the entire alkylation reaction is improved, and the device has the advantages of low equipment investment, stable product quality, low energy consumption, etc. It is particularly suitable for medium and large-scale alkylation reactions.
[0039] The device of the present invention is used to carry out alkylation reaction, which can realize continuous production, high degree of automation, high production efficiency of the entire alkylation reaction, good controllability of reaction temperature, safe production process and low production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Figure 1 It is a structural schematic diagram of the device of the present invention;
[0041] In the figure, 1 is preheater I; 2 is preheater II; 3 is high-efficiency mixer I; 4 is high-efficiency mixer II; 5 is high-efficiency mixer III; 6 is shell and tube reactor I; 7 is shell and tube reactor II; 8 is shell and tube reactor III; 9 is water vapor condenser cooler; 10 is water vapor condensate tank; 11 is vacuum pump inlet condenser cooler; 12 is vacuum pump; 13 is pressure-stabilizing tank; 14 is tower feed vaporizer; 15 is reaction distillation tower; 16 is reaction temperature control equipment of reaction distillation tower; 17 is pressure reducing valve; 18 is pressure step-down regulating system. DETAILED DESCRIPTION
[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments, and the preferred embodiment of the present invention is given in the specification. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0043] The present invention will be further described below in conjunction with the accompanying drawings:
[0044] like Figure 1 As shown, the device includes a tubular reaction module, a tubular reactor water evaporation heat removal circulation module and a reaction distillation module:
[0045] The shell-and-tube reaction module includes a preheater, a high-efficiency mixer, a shell-and-tube reactor and a pressure stabilizing tank 13. Isobutylene is fed in liquid phase, and a high-efficiency liquid-liquid mixer can be selected. According to the different phases of the isobutylene raw material, different types of high-efficiency mixers are selected; the preheater is connected to the high-efficiency mixer, the high-efficiency mixer is connected to the feed port of the shell-and-tube reactor, the discharge port of the shell-and-tube reactor is connected to the pressure stabilizing tank 13, and the pressure stabilizing tank 13 is provided with a pressure step-by-step regulating system 18 for controlling the alkylation reaction pressure in the shell-and-tube reactor.
[0046] The number of tubular reactors can be selected according to actual needs. According to the restrictions on raw materials and products, the number of tubular reactors can be 1 or more, and more here means more than 2. When the number of tubular reactors is more than 2, that is, more than 2, the connection between the tubular reactors is in series and / or in parallel. Preferably, the number of tubular reactors is 1 to 3. For the tubular reactors in series, the feeding method of the alkylating agent isobutylene can be added before the first tubular reactor, or it can be added separately, that is, added before each tubular reactor. When added separately, the amount of isobutylene at each addition point can be the same or different, and generally the tubular reactors are selected to be fed in decreasing order one by one.
[0047] The number of efficient mixers can be selected according to actual needs, for example, the number of efficient mixers is 1, or multiple. Generally, when the shell and tube reactor is multiple, each shell and tube reactor can be equipped with an efficient mixer, or other similar equipment that disperses and mixes uniformly. The shell and tube reactor can select the commonly used shell and tube reactor on the market, and its specifications are not strictly limited. The catalyst for catalyzing the alkylation reaction of meta-cresol and / or p-cresol and isobutylene is loaded in the tube or between the tubes of the shell and tube reactor. As for the catalyst, a liquid catalyst can be selected, or a solid catalyst can be selected, which can be selected according to actual needs. For the solid catalyst, it can be loaded in the tube of the shell and tube reactor, or it can be loaded between the tubes of the shell and tube reactor.
[0048] exist Figure 1 The m-, m- and / or p-cresol and liquid isobutylene are preheated in preheater I1 and preheater II2, respectively, to 40-70°C; the shell-and-tube reactor comprises shell-and-tube reactor I6, shell-and-tube reactor II7 and shell-and-tube reactor III8 which are sequentially connected in series; and the high-efficiency mixer comprises high-efficiency mixer I3, high-efficiency mixer II4 and high-efficiency mixer III5.
[0049] The outlet of preheater II 2 is respectively connected to the inlet I of high-efficiency mixer I 3, the inlet I of high-efficiency mixer II 4 and the inlet I of high-efficiency mixer III 5; the outlet of preheater I 1 is connected to the inlet II of high-efficiency mixer I 3, the outlet of high-efficiency mixer I 3 is connected to the feed port of shell and tube reactor I 6, the discharge port of shell and tube reactor I 6 is connected to the inlet II of high-efficiency mixer II 4, the outlet of high-efficiency mixer II 4 is connected to the feed port of shell and tube reactor II 7, the discharge port of shell and tube reactor II 7 is connected to the inlet II of high-efficiency mixer III 5, the outlet of high-efficiency mixer III 5 is connected to the feed port of shell and tube reactor III 8, and the discharge port of shell and tube reactor III 8 is connected to the inlet of pressure-surge tank 13.
[0050] When three serially connected tubular reactors are provided in the device, the liquid phase isobutylene can be added in its entirety before the tubular reactor I6; or it can be added in three portions, with 40-100% of the total amount added before the tubular reactor I6, 0-50% of the total amount added before the tubular reactor II7, and 0-30% of the total amount added before the tubular reactor III8. For example, the liquid phase isobutylene is fed according to the following scheme: 65% of the total amount is added before the tubular reactor I6, 25% of the total amount is added before the tubular reactor II7, and 10% of the total amount is added before the tubular reactor III8.
[0051] The liquid isobutylene added at the first place is dispersed and mixed with m- and / or p-cresol in the high-efficiency mixer I3, and then sent to the shell-and-tube reactor I6 for alkylation reaction. The reaction temperature is 50-90°C, preferably 60-80°C; the reaction pressure is 6-14 barg, preferably 8-10 barg.
[0052] The liquid isobutylene added at the second place is dispersed and mixed with the alkylation reaction product in the high-efficiency mixer II 4, and then sent to the shell-and-tube reactor II 7 for alkylation reaction. The reaction temperature is 50-90° C., preferably 60-80° C.; the reaction pressure is 6-14 barg, preferably 8-10 barg.
[0053] The liquid isobutylene added at the third place is dispersed and mixed with the alkylation reaction product in the high-efficiency mixer III 5, and then sent to the shell-and-tube reactor III 8 for alkylation reaction. The reaction temperature is 50-90° C., preferably 60-80° C.; the reaction pressure is 6-14 barg, preferably 8-10 barg.
[0054] The water evaporation and heat removal circulation module of the shell and tube reactor comprises a water vapor condenser cooler 9, a water vapor condensate tank 10, a vacuum pump inlet condenser cooler 11 and a vacuum pump 12, wherein the water vapor condenser cooler 9 can select an air cooler, which can reduce the production energy consumption of the device compared with the use of circulating water condensation cooling; the vacuum pump inlet condenser cooler 11 uses circulating water cooling because of the low cooling temperature; the water vapor outlet of the shell and tube reactor I 6, the water vapor outlet of the shell and tube reactor II 7 and the water vapor outlet of the shell and tube reactor III 8 are respectively connected to the inlet of the water vapor condenser cooler 9 through pipelines, the outlet of the water vapor condenser cooler 9 is connected to the inlet I of the water vapor condensate tank 10, and the outlet I of the water vapor condensate tank 10 is respectively connected to the water inlet of the shell and tube reactor I 6, the water inlet of the shell and tube reactor II 7 and the water inlet of the shell and tube reactor III 8, the outlet II of the water vapor condensate tank 10 is connected to the inlet of the vacuum pump inlet condenser cooler 9, the outlet I of the vacuum pump inlet condenser cooler 9 is connected to the inlet II of the water vapor condensate tank 10, and the outlet II of the vacuum pump inlet condenser cooler 9 is connected to the vacuum pump 12.
[0055] During the alkylation reaction, the pressure in the water evaporation and heat removal circulation module of the shell-and-tube reactor is controlled by vacuum pumping. In the present invention, the pressure of the water evaporation and heat removal circulation module of the shell-and-tube reactor is controlled to be 7-30 kPa(a), preferably 15-20 kPa(a).
[0056] The pressure stabilizing tank 13 is provided with a pressure step-by-step regulating system 18, which can control the pressure of the shell-and-tube reactor during the alkylation reaction. In the present invention, the pressure of the shell-and-tube reactor is controlled to be 6-14 barg, preferably 8-10 barg.
[0057] The reaction distillation module includes a tower feed vaporizer 14, a reaction distillation tower reaction temperature control device 16 and a reaction distillation tower 15, wherein the tower feed vaporizer 14 and the reaction distillation tower reaction temperature control device 16 can respectively select a shell and tube heat exchanger, the pressure stabilizing tank 13 is connected to the inlet of the tower feed vaporizer 14, and a pressure reducing valve 17 is provided on the pipeline between the pressure stabilizing tank 13 and the tower feed vaporizer 14, the gas phase discharge port of the tower feed vaporizer 14 is connected to the lower part of the reaction distillation tower 15, the liquid phase discharge port of the tower feed vaporizer 14 is connected to the inlet of the reaction distillation tower reaction temperature control device 16, and the outlet of the reaction distillation tower reaction temperature control device 16 is connected to the upper part of the reaction distillation tower 15, and the reaction distillation tower 15 is provided with a distillation section, a reaction section and a stripping section from top to bottom.
[0058] The internals of the rectifying section are fillers or trays, and the specific rectifying section can be one or more sections. The rectifying section is multi-section, which means that it includes more than two rectifying sections. The tower of the reaction section is filled with a solid catalyst, and the alkylation reaction and the alkylation distillation are coupled to improve the conversion rate of the reaction raw materials and the reaction effect. The reaction section can also be one or more sections, and the reaction section is multi-section, which means that it includes more than two reaction sections. The internals of the stripping section are fillers or trays, and the specific stripping section can be one or more sections. The stripping section is multi-section, which means that it includes more than two stripping sections.
[0059] A pressure reducing valve 17 is provided on the pipeline between the pressure stabilizing tank 13 and the tower feed vaporizer 14. After the pressure reducing valve 17 is opened, the pressure after the valve is controlled to be 5-20 kPa(a), preferably 8-12 kPa(a).
[0060] Furthermore, after opening the pressure reducing valve 17, the material in the pressure stabilizing tank 13 is passed into the tower feed vaporizer 14, and the material is partially vaporized at a temperature of 110-150°C, and a gas phase material and a liquid phase material are formed at the upper and lower parts of the tower feed vaporizer 14, respectively. Preferably, when the material is vaporized in the tower feed vaporizer 14, the temperature of the material in the vaporizer 14 is controlled to be 120-140°C.
[0061] The liquid-phase material is transferred from the liquid-phase discharge port provided on the tower feed vaporizer 14 to the reaction temperature control device 16 of the reaction distillation tower for temperature adjustment. The liquid-phase material after temperature adjustment enters the reaction distillation tower 15 through a pipeline from the upper part of the reaction distillation tower 15; the gas-phase material enters the reaction distillation tower 15 through a pipeline from the gas-phase discharge port provided on the tower feed vaporizer 14 and the lower part of the reaction distillation tower 15, and reacts with the liquid-phase material entering the reaction distillation tower in the reaction section. The reaction temperature is 50-90°C, the reaction pressure is 5-20kpa(a), the gas-phase material not participating in the reaction is extracted from the top of the tower, and the target product is extracted from the bottom of the tower.
[0062] In a preferred embodiment, when the reaction is carried out in the reaction section, the reaction temperature is 60-80°C and the reaction pressure is 8-12 kpa(a).
[0063] The use process of the present invention is as follows:
[0064] Example 1
[0065] This embodiment is an alkylation reaction of p-cresol with liquid isobutylene to produce di-tert-butyl p-cresol (BHT). The shell-and-tube reactor selects three shell-and-tube reactors in series, namely, shell-and-tube reactor I, shell-and-tube reactor II and shell-and-tube reactor III, and each shell-and-tube reactor is filled with a solid catalyst. Each shell-and-tube reactor is equipped with three high-efficiency liquid-liquid mixers, namely, high-efficiency liquid-liquid mixer I, high-efficiency liquid-liquid mixer II and high-efficiency liquid-liquid mixer III. Liquid phase isobutylene is added in three times, and the feeding is carried out according to the following scheme: 65% of the total amount is added before shell-and-tube reactor I 6, 25% of the total amount is added before shell-and-tube reactor II 7, and 10% of the total amount is added before shell-and-tube reactor III 8.
[0066] The pressure of the surge tank is controlled at 8 barg by the step-by-step regulation system on the surge tank to ensure that the liquid isobutylene does not flash vaporize after entering the shell-and-tube reaction module and the alkylation reaction is carried out in the liquid phase.
[0067] Turn on the vacuum pump and control the pressure of the condenser cooler at the vacuum pump inlet to 10 kPa (a). During the production process, the pressure at the steam outlet of the shell-and-tube reactor is controlled to be approximately 16 kPa (a), and the corresponding water saturation temperature is approximately 55 °C.
[0068] 10 kmol / h p-cresol was added to preheater I and preheated to 60°C, and 15.6 kmol / h liquid isobutylene was added to preheater II and preheated to 60°C. After the preheating, the two streams were fully mixed in the high-efficiency liquid-liquid mixer I and then sent to the shell-and-tube reactor I for alkylation reaction. The reaction temperature of the shell-and-tube reactor I was controlled to be 65°C and the reaction pressure was 9.5 barg; the reaction residence time in the shell-and-tube reactor I was 0.5~1.5h.
[0069] The alkylation reaction product is transported from the discharge port of the shell-and-tube reactor I into the high-efficiency liquid-liquid mixer II, and 6 kmol / h of liquid isobutylene is added to the high-efficiency liquid-liquid mixer II. After the two streams of materials are fully mixed in the high-efficiency liquid-liquid mixer II, they are sent to the shell-and-tube reactor II for further reaction; the reaction temperature in the shell-and-tube reactor II is controlled to be 70° C. and the reaction pressure is 9 barg; the reaction residence time in the shell-and-tube reactor II is 1-2 h.
[0070] The discharge port of the tubular reactor II conveys the alkylation reaction product into the high-efficiency liquid-liquid mixer III, and at the same time, 2.4 kmol / h of liquid isobutylene is added to the high-efficiency liquid-liquid mixer III. After the two streams of materials are fully mixed in the high-efficiency liquid-liquid mixer III, they are sent to the tubular reactor III for further reaction; the reaction temperature in the tubular reactor III is controlled to be 75° C., and the reaction pressure is 8.5 barg; the reaction residence time in the tubular reactor III is 1-2 h.
[0071] The discharge port of the tubular reactor III delivers the alkylation reaction product to a pressure-stabilizing tank, which is used to adjust and control the reaction pressure of the tubular reactor. In this embodiment, the operating temperature of the pressure-stabilizing tank is 75° C. and the operating pressure is 8 barg.
[0072] The alkylation reaction product in the pressure-surge tank is decompressed by the pressure reducing valve and then sent to the tower feed vaporizer. The pressure after the pressure reducing valve is controlled to be 10kpa(a), and flash evaporation occurs after the pressure reducing valve. The temperature of the logistics after the valve is reduced by about 5°C. At the same time, the phase of the logistics changes from liquid phase to gas-liquid two-phase, and the mass fraction of the gas phase is about 4%;
[0073] Further, the gas-liquid two-phase flow after the above-mentioned pressure reducing valve is sent to the tower feed vaporizer and heated to 130°C to form gas phase material and liquid phase material, and the gas phase mass fraction is about 15%; the molar composition of the gas phase material is as follows: 33% isobutylene, 29% dimerized isobutylene, 16% trimerized isobutylene, 4% p-cresol, 13% mono-tert-butyl-p-cresol, and 5% di-tert-butyl-p-cresol; the rough molar composition of the liquid phase material is as follows: 2% dimerized isobutylene, 5% trimerized isobutylene, 4% p-cresol, 41% mono-tert-butyl-p-cresol, and 48% di-tert-butyl-p-cresol.
[0074] The liquid phase material in the tower feed vaporizer is adjusted to 60°C by the reaction temperature equipment (e.g., shell-and-tube heat exchanger) of the reaction distillation tower, and enters from the upper part of the reaction distillation tower, and the gas phase material enters from the lower part of the reaction distillation tower. The reaction distillation tower is equipped with 1 distillation section, 2 reaction sections (each reaction section is filled with solid catalyst), and 1 stripping section; isobutylene is alkylated with p-cresol and mono-tert-butyl-p-cresol in the reaction section, the reaction pressure is 10kpa (a), and the temperature range of the upper and lower ends of the reaction section is 62~72°C.
[0075] Trace isobutylene (less than 0.5%) and isobutylene dimer are discharged from the top of the reaction distillation tower, and isobutylene trimer, mono-tert-butyl-p-cresol and di-tert-butyl-p-cresol are discharged from the bottom of the reaction distillation tower; the isobutylene content at the top of the tower is very low, and no recovery equipment is needed; the material in the bottom of the tower is sent to the distillation tower for refining to obtain high-purity di-tert-butyl-p-cresol.
[0076] The other processes of the present invention can adopt existing technologies.
[0077] The above are only preferred embodiments of the present invention, but do not limit the patent scope of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features with equivalent ones. Any equivalent structure made by using the contents of the present invention specification, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.
Claims
1. A device for continuous alkylation reaction of m-cresol and / or p-cresol, characterized in that it It includes a shell-and-tube reaction module, a shell-and-tube reactor water evaporation heat removal circulation module and a reaction distillation module: The shell-and-tube reaction module comprises a preheater, a high-efficiency mixer, a shell-and-tube reactor and a pressure stabilizing tank, wherein the preheater is connected to the high-efficiency mixer, the high-efficiency mixer is connected to the feed port of the shell-and-tube reactor, the discharge port of the shell-and-tube reactor is connected to the pressure stabilizing tank, and the pressure stabilizing tank is provided with a pressure step-by-step regulating system; The water evaporation heat removal circulation module of the shell and tube reactor comprises a water vapor condenser cooler, a water vapor condensate tank, a vacuum pump inlet condenser cooler and a vacuum pump, the water vapor outlet of the shell and tube reactor is connected to the inlet of the water vapor condenser cooler, the outlet of the water vapor condenser cooler is connected to the inlet I of the water vapor condensate tank, the outlet I of the steam condensate tank is connected to the water inlet of the shell and tube reactor, the outlet II of the water vapor condensate tank is connected to the inlet of the vacuum pump inlet condenser cooler, the outlet I of the vacuum pump inlet condenser cooler is connected to the inlet II of the water vapor condensate tank, and the outlet II of the vacuum pump inlet condenser cooler is connected to the vacuum pump; The tubes or inter-tubes of the tubular reactor are filled with a catalyst for catalyzing the alkylation reaction of m-cresol and / or p-cresol with isobutylene; The preheater includes a preheater I for preheating m-cresol and / or p-cresol and a preheater II for preheating isobutylene; the shell-and-tube reactor includes a shell-and-tube reactor I, a shell-and-tube reactor II and a shell-and-tube reactor III connected in series in sequence; the high-efficiency mixer includes a high-efficiency mixer I, a high-efficiency mixer II and a high-efficiency mixer III; The outlet of the preheater II is connected to the inlet I of the high-efficiency mixer I, the inlet I of the high-efficiency mixer II and the inlet I of the high-efficiency mixer III respectively; the outlet of the preheater I is connected to the inlet II of the high-efficiency mixer I, the outlet of the high-efficiency mixer I is connected to the feed port of the shell-and-tube reactor I, the discharge port of the shell-and-tube reactor I is connected to the inlet II of the high-efficiency mixer II, the outlet of the shell-and-tube reactor II is connected to the feed port of the shell-and-tube reactor II, the discharge port of the shell-and-tube reactor II is connected to the inlet II of the high-efficiency mixer III, the outlet of the high-efficiency mixer III is connected to the feed port of the shell-and-tube reactor III, and the discharge port of the shell-and-tube reactor III is connected to the inlet of the surge tank; The reaction distillation module comprises a tower feed vaporizer, a reaction temperature control device for a reaction distillation tower and a reaction distillation tower, the pressure stabilizing tank is connected to the inlet of the tower feed vaporizer, a pressure reducing valve is arranged on the pipeline between the pressure stabilizing tank and the tower feed vaporizer, the gas phase discharge port of the tower feed vaporizer is connected to the lower part of the reaction distillation tower, the liquid phase discharge port of the tower feed vaporizer is connected to the inlet of the reaction temperature control device for the reaction distillation tower, the outlet of the reaction temperature control device for the reaction distillation tower is connected to the upper part of the reaction distillation tower, and the reaction distillation tower is provided with a distillation section, a reaction section and a stripping section in order from top to bottom; The internals of the rectifying section are fillers or trays, and the rectifying section consists of one or more sections; the tower of the reaction section is filled with a solid catalyst, and the reaction section consists of one or more sections; the internals of the stripping section are fillers or trays, and the stripping section consists of one or more sections; The method for carrying out the continuous alkylation reaction of the device comprises the following steps: (1) The preheated m-cresol and / or p-cresol and isobutylene are uniformly mixed in the high-efficiency mixer, and the obtained mixed material is introduced into the shell-and-tube reactor through the feed port of the shell-and-tube reactor through a pipeline, and an alkylation reaction is carried out at a temperature of 60-80° C. and a pressure of 8-10 barg. After the reaction is completed, the material obtained is transferred from the discharge port of the shell-and-tube reactor to a pressure-regulating tank through a pipeline; during the alkylation reaction, deoxygenated water is introduced into the shell-and-tube reactor, and the pressure in the water evaporation and heat removal circulation module of the shell-and-tube reactor is controlled to be 15-20 kPa (a), and the water vapor generated after negative pressure evaporation enters the water vapor condensation cooler from the water vapor outlet of the shell-and-tube reactor for condensation, and the condensed water obtained after condensation enters the water vapor condensation tank, and the condensed water in the water vapor condensation tank is then introduced into the shell-and-tube reactor to continue absorbing heat for negative pressure evaporation and heat removal; (2) Open the pressure reducing valve, and under the condition that the pressure after the control valve is 8~12kpa(a), the material in the pressure stabilizing tank is passed into the tower feed vaporizer, and the material is partially vaporized at a temperature of 120~140°C, and gaseous materials and liquid materials are formed at the upper and lower parts of the tower feed vaporizer respectively. The liquid material is transferred from the liquid phase discharge port provided on the tower feed vaporizer to the reaction temperature control device of the reaction distillation tower for temperature adjustment. The liquid material with adjusted temperature enters the reaction distillation tower through the pipeline from the upper part of the reaction distillation tower; the gaseous material enters the reaction distillation tower through the gas phase discharge port provided on the tower feed vaporizer through the pipeline from the lower part of the reaction distillation tower, and reacts with the liquid material entering the reaction distillation tower in the reaction section. The reaction temperature is 60~80°C, and the reaction pressure is 8~12kpa(a). The gaseous material not participating in the reaction is extracted from the top of the tower, and the target product is extracted from the bottom of the tower.
2. A method for continuous alkylation reaction using the device according to claim 1, characterized in that: It includes the following steps: (1) The preheated m-cresol and / or p-cresol and isobutylene are uniformly mixed in the high-efficiency mixer, and the obtained mixed material is introduced into the shell-and-tube reactor through the feed port of the shell-and-tube reactor through a pipeline, and an alkylation reaction is carried out at a temperature of 60-80° C. and a pressure of 8-10 barg. After the reaction is completed, the material obtained is transferred from the discharge port of the shell-and-tube reactor to a pressure-regulating tank through a pipeline; during the alkylation reaction, deoxygenated water is introduced into the shell-and-tube reactor, and the pressure in the water evaporation and heat removal circulation module of the shell-and-tube reactor is controlled to be 15-20 kPa (a), and the water vapor generated after negative pressure evaporation enters the water vapor condensation cooler from the water vapor outlet of the shell-and-tube reactor for condensation, and the condensed water obtained after condensation enters the water vapor condensation tank, and the condensed water in the water vapor condensation tank is then introduced into the shell-and-tube reactor to continue absorbing heat for negative pressure evaporation and heat removal; (2) Open the pressure reducing valve, and under the condition that the pressure after the control valve is 8~12kpa(a), the material in the pressure stabilizing tank is passed into the tower feed vaporizer, and the material is partially vaporized at a temperature of 120~140°C, and gaseous materials and liquid materials are formed at the upper and lower parts of the tower feed vaporizer respectively. The liquid material is transferred from the liquid phase discharge port provided on the tower feed vaporizer to the reaction temperature control device of the reaction distillation tower for temperature adjustment. The liquid material with adjusted temperature enters the reaction distillation tower through the pipeline from the upper part of the reaction distillation tower; the gaseous material enters the reaction distillation tower through the gas phase discharge port provided on the tower feed vaporizer through the pipeline from the lower part of the reaction distillation tower, and reacts with the liquid material entering the reaction distillation tower in the reaction section. The reaction temperature is 60~80°C, and the reaction pressure is 8~12kpa(a). The gaseous material not participating in the reaction is extracted from the top of the tower, and the target product is extracted from the bottom of the tower.