Continuous production device for preparing methyl tetrahydrophthalic anhydride
By designing a continuous production device with multiple feed ports and thermal coupling, the problems of time-consuming operation and system instability in the intermittent production process of methyl tetrahydrophenyl anhydride are solved, and high efficiency and low energy consumption are achieved, ensuring high purity of the product and stability.
Patent Information
- Application Number
- CN202420604351.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2025-01-07
- Estimated Expiration
- 2034-03-27
AI Technical Summary
In the prior art, the batch production process of methyltetrahydrophenyl anhydride has problems such as time-consuming and labor-intensive operation, unstable system, slow reactions resulting in a decrease in reactant concentration in the later stage of the reaction, and insufficient production capacity, making it difficult to achieve efficient and stable continuous production.
A device including synthesis reactor, a manic anhydride storage tank, a carbon five storage tank, a distillation tower, a condenser, a thermosiphon reboiler, and isomerization reactor were designed, and the device was divided into sections through multiple carbon five feed ports. Reaction, use crude methyl tetrahydrophenyl anhydride as a reaction aid, and set up a thermosiphon reboiler for thermal coupling to improve reaction efficiency and energy efficiency.
The industrial continuous production of methyl tetrahydrophenyl anhydride is achieved, the synthesis reaction efficiency is improved, the production energy consumption is reduced, and the quality stability and high purity of the product are ensured.
Smart Images
Figure CN222305746U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of chemical synthesis, and specifically relates to a continuous production device for preparing methyltetrahydrophthalic anhydride. Background Art
[0002] Methyltetrahydrophthalic anhydride (MeTHPA) is a new type of liquid organic anhydride epoxy resin curing agent with excellent performance. It has the advantages of long-term storage at room temperature, low freezing point, low volatility, and low toxicity. Therefore, it is widely used in motors, dry-type transformers, high-voltage switches, mutual inductors, line output transformers, household capacitors, power capacitors and resistors, and the impregnation, casting and winding of integrated circuits. With the continuous improvement of the requirements for the reliability of insulation structures in the motor, electronics, and electrical industries, the application of this type of curing agent has developed rapidly, and the requirements for its quality stability are very urgent. Therefore, it is imperative to develop and research continuous production equipment for methyltetrahydrophthalic anhydride products with better performance.
[0003] Industrial synthesis of methyltetrahydrophthalic anhydride is obtained by synthesizing maleic anhydride and isoprene and isomerization of isoprene in C5. The cracking raw material C5 is pretreated with DMF extraction and distillation, and the intermediate fraction rich in methylbutadiene is cut and reacted with maleic anhydride in an auxiliary agent; after the reaction, the unreacted components are evaporated and isomerized into liquid anhydride, and the finished product is obtained by vacuum distillation. At present, the domestic production of methyltetrahydrophthalic anhydride mainly adopts an intermittent production process, which has many shortcomings, such as time-consuming and labor-intensive operation, unstable system, slow reaction when the concentration of reactants decreases in the later stage of the reaction, thereby increasing the reaction time, differences in products from different batches, insufficient production capacity, etc. Utility Model Content
[0004] In order to overcome the deficiencies of the prior art, the utility model provides a continuous production device for preparing methyltetrahydrophthalic anhydride, which can not only realize the continuous production of methyltetrahydrophthalic anhydride in industry, but also improve the synthesis efficiency of methyltetrahydrophthalic anhydride and reduce production energy consumption.
[0005] The technical solution adopted by the utility model to solve the technical problem is: a continuous production device for preparing methyltetrahydrophthalic anhydride, which comprises a synthesis reactor, a maleic anhydride storage tank, a carbon five storage tank, a first distillation tower, a first condenser, a first thermosyphon reboiler, an isomerization reactor, a second distillation tower, a second condenser, a second thermosyphon reboiler, a product stripping tower, a third thermosyphon reboiler, and a vacuum pump; the synthesis reactor is a tubular reactor, a maleic anhydride feed port for introducing maleic anhydride raw materials is provided on the top of the synthesis reactor, and a plurality of carbon five feed ports for introducing carbon five raw materials are provided on the side wall of the synthesis reactor from top to bottom, the maleic anhydride feed port is connected to the maleic anhydride storage tank discharge port, and the plurality of carbon five feed ports are connected to the maleic anhydride storage tank discharge port. The feed port is connected to the discharge port of the C5 storage tank, and the bottom discharge port of the synthesis reactor is connected to the feed port in the first distillation tower; the first distillation tower is an atmospheric distillation tower, and a first thermal syphon reboiler is installed at the bottom of the first distillation tower, the top discharge port of the first distillation tower is connected to the feed port of the first condenser, and the liquid phase discharge port of the first condenser is divided into two branches: one branch refluxes to the first distillation tower, and the other branch is connected to the feed port of the C5 storage tank, the feed port in the first distillation tower is connected to the bottom discharge port of the synthesis reactor, the discharge port in the first distillation tower is connected to the auxiliary agent feed port of the synthesis reactor, and the bottom discharge port of the first distillation tower is divided into two branches The isomerization reactor is a tubular reactor, and a catalyst feed port for introducing an isomerization catalyst is provided on the feed pipe connecting the isomerization reactor and the first distillation tower, and the top discharge port of the isomerization reactor is connected to the middle feed port of the second distillation tower; the second distillation tower is a vacuum distillation tower, and a second thermosyphon reboiler is installed at the bottom of the second distillation tower, and the top discharge port of the second distillation tower is connected to the feed port of the second condenser, and the second condenser is connected to a vacuum pump, and the liquid phase discharge port of the second condenser is divided into two branches: one branch is connected to the feed port of the first thermosyphon reboiler, and the other branch is connected to the feed port of the isomerization reactor; the isomerization reactor is a tubular reactor, and a catalyst feed port for introducing an isomerization catalyst is provided on the feed pipe connecting the isomerization reactor and the first distillation tower, and the top discharge port of the isomerization reactor is connected to the middle feed port of the second distillation tower; the second distillation tower is a vacuum distillation tower, and a second thermosyphon reboiler is installed at the bottom of the second distillation tower, and the top discharge port of the second distillation tower is connected to the feed port of the second condenser, and the second condenser is connected to a vacuum pump, and the liquid phase discharge port of the second condenser is divided into two branches: one branch is connected to the feed port of the first condenser, and the second condenser is connected to the second condenser. The product stripping tower is an auxiliary equipment of the second distillation tower, and the top discharge port of the stripping tower refluxes to the second distillation tower, and the bottom discharge port of the stripping tower is divided into two branches: one branch is connected to the feed port of the second thermosyphon reboiler, and the other branch produces heavy components (by-products); the product stripping tower is an auxiliary equipment of the second distillation tower, and the top discharge port of the stripping tower refluxes to the second distillation tower, and the bottom discharge port of the stripping tower is divided into two branches: one branch is connected to the feed port of the third thermosyphon reboiler, and the other branch produces methyltetrahydrophthalic anhydride finished product.
[0006] By adopting the above technical scheme, the continuous production device of the utility model truly realizes the industrialized continuous production of methyltetrahydrophthalic anhydride, and the synthesis reaction efficiency is high and the reaction energy consumption is low. Compared with the prior art, the continuous production device has the following advantages: (i) The synthesis reactor is provided with multiple carbon five feed ports to avoid the problems of a sharp increase in reaction temperature and insufficient contact of reaction raw materials caused by simultaneous feeding. Because the synthesis reaction of maleic anhydride and carbon five is an exothermic reaction, simultaneous feeding makes the reaction temperature too high, thereby reducing the reaction rate, and multiple feed ports are provided for staged reaction, which can well control the progress and temperature of the synthesis reaction to avoid a sharp increase in reactor temperature and reduce energy consumption, and make the reaction raw materials maleic anhydride and carbon five fully contact to improve the synthesis reaction efficiency; (ii) The crude methyltetrahydrophthalic anhydride obtained in the first distillation tower is returned to the synthesis reactor through the auxiliary agent feed port to act as a contact agent between maleic anhydride and carbon five. The auxiliary agent for the C5 synthesis reaction uses crude methyltetrahydrophthalic anhydride as a reaction auxiliary agent. As described by Mo Changyi in "Research on the Synthesis Process of Methyltetrahydrophthalic Anhydride", "when a curing agent is used as a solvent, the reaction rate is slightly higher than the reaction rate when acetone is used as a solvent. When a curing agent is used as a solvent, the solvent can be used multiple times." At the same time, the inventor of the utility model believes that crude methyltetrahydrophthalic anhydride can increase the viscosity of maleic anhydride solution, thereby prolonging the contact time between maleic anhydride liquid and C5 to improve the synthesis reaction efficiency; (iii) A thermal syphon reboiler is provided at the bottom of the first distillation tower. The thermal syphon reboiler uses the heat of the finished methyltetrahydrophthalic anhydride to heat the bottom of the first distillation tower to form thermal coupling, so that the energy consumption of the entire device can be saved.
[0007] It is further configured that the synthesis reactor is a tubular reactor, each of its C5 feed pipes is provided with a small hole, and a baffle is also provided in the tubular reactor.
[0008] By adopting the above technical solution, a small hole is set on the C5 feed pipe, and a baffle is set inside the reactor to make the reaction raw materials fully contact, strengthen the mass transfer and heat transfer process, and increase the reaction rate.
[0009] It is further configured that: a pressure relief valve is installed on the pipeline connecting the synthesis reactor and the first distillation tower.
[0010] By adopting the above technical solution, the pressure of the synthesis reactor can be flexibly controlled, and the feed pressure of the first distillation tower can also be reduced to perform separation in the first distillation tower.
[0011] It is further configured as follows: the discharge port of the first thermosyphon reboiler is connected to the lower inlet of the first distillation tower; the discharge port of the second thermosyphon reboiler is connected to the lower inlet of the second distillation tower; the discharge port of the third thermosyphon reboiler is connected to the lower inlet of the product stripping tower.
[0012] It is further configured that: a branch outlet for obtaining the methyltetrahydrophthalic anhydride finished product in the bottom discharge port of the product stripping tower is connected to the side feed port of the first thermal syphon reboiler, and the side discharge port of the first thermal syphon reboiler is used to obtain the finished product.
[0013] The continuous production method for preparing methyltetrahydrophthalic anhydride using the continuous production device as described above comprises the following steps:
[0014] Step 1: Synthesis reaction:
[0015] (a) storing maleic anhydride in the maleic anhydride storage tank and storing C5 in the C5 storage tank, respectively feeding the maleic anhydride into the synthesis reactor through the maleic anhydride feed port and the plurality of C5 feed ports to carry out a synthesis reaction to obtain a synthetic product, wherein the synthesis reaction temperature is 70-85° C. and the pressure is 0.10-0.25 MpaG;
[0016] (b) before the synthetic product obtained in the synthesis reactor is fed into the first distillation tower, the pressure of the synthetic product is reduced to normal pressure through the pressure relief valve; the synthetic product is separated in the first distillation tower, and then the top component is condensed by the first condenser to obtain unreacted C5, which is then fed into the C5 storage tank, a portion of the components in the tower is extracted from the first distillation tower and refluxed into the synthesis reactor to serve as a synthetic reaction auxiliary agent, and the bottom component is extracted from the bottom of the first distillation tower to obtain a crude methyltetrahydrophthalic anhydride, which is then fed into the isomerization reactor for isomerization reaction;
[0017] Step 2: Isomerization reaction:
[0018] (c) feeding an isomerization catalyst through a catalyst feed port of a feed pipe connecting the isomerization reactor and the first distillation tower, and passing the isomerization catalyst and the crude methyltetrahydrophthalic anhydride obtained in the first distillation tower into the isomerization reactor for isomerization reaction to obtain an isomerized product, wherein the isomerization reaction temperature is 180-220° C. and the pressure is 0.1-0.2 MPaG;
[0019] Step 3: Distillation separation:
[0020] (d) the isomerization product obtained in the isomerization reactor is passed into the second distillation tower for separation, the top component is condensed by the second condenser to obtain unreacted maleic anhydride, which is then passed into the maleic anhydride storage tank, the bottom component is extracted from the bottom of the second condenser to obtain a heavy component, and the components in the tower are separated and purified by the product stripping tower to obtain a finished methyltetrahydrophthalic anhydride.
[0021] It is further configured that: the methyltetrahydrophthalic anhydride product obtained in the product stripping tower is sent to the first thermal syphon reboiler for thermal coupling to provide heat to the first distillation tower.
[0022] By adopting the above technical solution, the heat of the finished methyltetrahydrophthalic anhydride product is used to heat the bottom of the first distillation tower, thereby saving energy consumption of the entire device.
[0023] It is further configured as follows: the feed ratio of maleic anhydride to C5 in the synthesis reactor is 1:1.02 to 1:1.10.
[0024] It is further configured that: in the synthesis reactor, the feed ratio of maleic anhydride to the crude methyltetrahydrophthalic anhydride serving as a synthesis reaction auxiliary agent is 1:0.4-1:0.6.
[0025] It is further configured as follows: controlling the top temperature of the first distillation tower to be 40~45°C and the pressure to be 0.005~0.010MpaG; controlling the top temperature of the second distillation tower to be 105~120°C and the pressure to be -0.096~-0.092MpaG; controlling the top temperature of the product stripping tower to be 110~130°C and the pressure to be -0.092~-0.090MpaG.
[0026] By adopting the above technical solution, the temperature and pressure of the first distillation tower, the second distillation tower and the stripping tower are controlled to improve the separation efficiency.
[0027] It is further configured that: the isomerization catalyst is polyphosphoric acid or potassium acetate.
[0028] Compared with the prior art, the continuous production device for preparing methyltetrahydrophthalic anhydride of the utility model has the following beneficial effects: (i) the continuous production of methyltetrahydrophthalic anhydride is truly realized; (ii) the synthesis reactor is provided with multiple carbon five feed ports, so as to avoid the problems of rapid increase in reaction temperature and insufficient contact of reaction raw materials caused by simultaneous feeding, thereby saving energy consumption of the synthesis reaction and improving reaction efficiency; (iii) the crude methyltetrahydrophthalic anhydride obtained in the first distillation tower is returned to the synthesis reactor through the auxiliary agent feed port to serve as an auxiliary agent for the synthesis reaction of maleic anhydride and carbon five, which can further improve the reaction efficiency; (iv) carbon five is separated out by the first distillation tower, which is beneficial to the recovery and utilization of carbon five; (v) separation and purification are carried out by the first distillation tower, the second distillation tower and the stripping tower of the continuous production device, so as to improve the purity of the final product, thereby meeting higher application requirements of the curing agent; (vi) the heat of the finished methyltetrahydrophthalic anhydride is used to heat the bottom of the first distillation tower, thereby reducing production energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 It is a schematic diagram of a continuous production device for preparing methyltetrahydrophthalic anhydride according to the utility model;
[0030] In the figure: 1. synthesis reactor; 101. maleic anhydride feed port; 102. C5 feed port; 103. bottom discharge port; 104. auxiliary agent feed port; 105. small hole; 106. baffle; 107. pressure relief valve; 3. maleic anhydride storage tank; 2. C5 storage tank; 4. first distillation tower; 5. first condenser; 6. first thermosyphon reboiler; 7. isomerization reactor; 701. catalyst feed port; 8. second distillation tower; 9. second condenser; 10. second thermosyphon reboiler; 11. product stripping tower; 12. third thermosyphon reboiler; 13. vacuum pump. DETAILED DESCRIPTION
[0031] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0034] Reference Figure 1 The continuous production device for preparing methyltetrahydrophthalic anhydride includes a synthesis reactor 1, a maleic anhydride storage tank 3, a C5 storage tank 2, a first distillation tower 4, a first condenser 5, a first thermosyphon reboiler 6, an isomerization reactor 7, a second distillation tower 8, a second condenser 9, a second thermosyphon reboiler 10, a product stripping tower 11, a third thermosyphon reboiler 12, and a vacuum pump 13.
[0035] The synthesis reactor 1 is a tubular reactor, the top of the synthesis reactor 1 is provided with a maleic anhydride feed port 101 for introducing maleic anhydride raw materials, and the side wall of the synthesis reactor 1 is provided with a plurality of C5 feed ports 102 for introducing C5 raw materials from top to bottom, the maleic anhydride feed port 101 is connected to the discharge port of the maleic anhydride storage tank 3, the plurality of C5 feed ports 102 are connected to the discharge port of the C5 storage tank 2, the bottom discharge port 103 of the synthesis reactor 1 is connected to the feed port in the first distillation tower 4; the first distillation tower 4 is a normal pressure distillation tower, the bottom of the first distillation tower 4 is equipped with a first thermosyphon reboiler 6, the first distillation tower 4 ... The top discharge port of tower 4 is connected to the feed port of the first condenser 5, and the liquid phase discharge port of the first condenser 5 is divided into two branches: one branch is refluxed to the first distillation tower 4, and the other branch is connected to the feed port of the C5 storage tank 2. The feed port in the first distillation tower 4 is connected to the bottom discharge port 103 of the synthesis reactor 1, and the discharge port in the first distillation tower 4 is connected to the auxiliary agent feed port 104 of the synthesis reactor 1. The bottom discharge port of the first distillation tower 4 is divided into two branches: one branch is connected to the feed port of the first thermal syphon reboiler 6, and the other branch is connected to the feed port of the isomerization reactor 7; the isomerization reactor 7 is a shell and tube reactor, and in the isomerization reactor 7, the isomerization reactor 7 is connected to the first thermal syphon reboiler 6, and ... A catalyst feed port 701 for introducing an isomerization catalyst is provided on a feed pipe connecting the isomerization reactor 7 to the first distillation tower 4, and the top discharge port of the isomerization reactor 7 is connected to the middle feed port of the second distillation tower 8; the second distillation tower 8 is a vacuum distillation tower, and a second thermosyphon reboiler 10 is installed at the bottom of the second distillation tower 8, and the top discharge port of the second distillation tower 8 is connected to the feed port of the second condenser 9, and the second condenser 9 is connected to a vacuum pump 13, and the liquid phase discharge port of the second condenser 9 is divided into two branches: one branch refluxes to the second distillation tower 8, and the other branch is connected to the feed port of the maleic anhydride storage tank 3, The feed port in the second distillation tower 8 is connected to the discharge port of the isomerization reactor 7, the discharge port in the second distillation tower 8 is connected to the feed port of the stripping tower 11, and the bottom discharge port of the second distillation tower 8 is divided into two branches: one branch is connected to the feed port of the second thermosyphon reboiler 10, and the other branch is used to produce heavy components (by-products); the product stripping tower 11 is an auxiliary equipment of the second distillation tower 8, and the top discharge port of the stripping tower 11 is refluxed to the second distillation tower 8, and the bottom discharge port of the stripping tower 9 is divided into two branches: one branch is connected to the feed port of the third thermosyphon reboiler 12, and the other branch is used to produce the finished methyltetrahydrophthalic anhydride.
[0036] The continuous production device for preparing methyltetrahydrophthalic anhydride of the utility model, in the specific preparation and production, refers to the following process:
[0037] Maleic anhydride raw material, C5 raw material and reaction aid are introduced into synthesis reactor 1 at a molar ratio of 1:1.05:0.5, wherein maleic anhydride raw material is introduced into synthesis reactor 1 through maleic anhydride feed port 101, C5 raw material is introduced into synthesis reactor 1 through multiple C5 feed ports 102 in batches, and reaction aid is introduced into auxiliary agent feed port 104, raw materials are fully contacted through baffle 106 for reaction, reaction products are introduced into first distillation tower 4, unreacted C5 is recovered at the top of first distillation tower 4, a part of which is drawn out in first distillation tower 4 and returned to synthesis reactor 1 for use as reaction aid, crude methyltetrahydrophthalic anhydride is obtained at the bottom of first distillation tower 4, and crude methyltetrahydrophthalic anhydride is introduced into isomerization reactor 7 with isomerization catalyst at a molar ratio of 1:0.002. Crude methyltetrahydrophthalic anhydride is isomerized in isomerization reactor 7, and then introduced into second distillation tower 8, and separated and purified at a top temperature of 105-108°C and a pressure of -0.096MpaG. Maleic anhydride is recovered at the top of the second distillation tower 8 as maleic anhydride raw material, and the reaction by-product heavy component is obtained at the bottom of the second distillation tower 8. Methyltetrahydrophthalic anhydride is obtained at the second distillation tower 8 and sent to the product stripping tower 11. It is further purified at a tower top temperature of 110-115°C and a pressure of -0.092MpaG to obtain a high-purity methyltetrahydrophthalic anhydride finished product. The methyltetrahydrophthalic anhydride finished product can also be used as a heat medium for the first thermal syphon reboiler 6 to heat the first distillation tower 4. Finally, the yield of the methyltetrahydrophthalic anhydride finished product is 98.5% and the purity is 99.9%.
[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A continuous production device for preparing methyltetrahydrophthalic anhydride, characterized in that: It comprises a synthesis reactor (1), a maleic anhydride storage tank (3), a C5 storage tank (2), a first distillation tower (4), a first condenser (5), a first thermosyphon reboiler (6), an isomerization reactor (7), a second distillation tower (8), a second condenser (9), a second thermosyphon reboiler (10), a product stripping tower (11), a third thermosyphon reboiler (12), and a vacuum pump (13); The synthesis reactor (1) is a tubular reactor, the top of the synthesis reactor (1) is provided with a maleic anhydride feed port (101) for introducing maleic anhydride raw material, and the side wall of the synthesis reactor (1) is provided with a plurality of C5 feed ports (102) for introducing C5 raw material from top to bottom, the maleic anhydride feed port (101) is connected to the discharge port of the maleic anhydride storage tank (3), the plurality of C5 feed ports (102) are connected to the discharge port of the C5 storage tank (2), and the discharge port (103) at the bottom of the synthesis reactor (1) is connected to the feed port in the first distillation tower (4); The first distillation tower (4) is a normal pressure distillation tower, a first thermosyphon reboiler (6) is installed at the bottom of the first distillation tower (4), the top discharge port of the first distillation tower (4) is connected to the feed port of the first condenser (5), the liquid phase discharge port of the first condenser (5) is divided into two branches: one branch is refluxed to the first distillation tower (4), and the other branch is connected to the feed port of the C5 storage tank (2), the feed port in the middle of the first distillation tower (4) is connected to the bottom discharge port (103) of the synthesis reactor (1), the discharge port in the middle of the first distillation tower (4) is connected to the auxiliary agent feed port (104) of the synthesis reactor (1), and the bottom discharge port of the first distillation tower (4) is divided into two branches: one branch is connected to the feed port of the first thermosyphon reboiler (6), and the other branch is connected to the feed port of the isomerization reactor (7); The isomerization reactor (7) is a shell-and-tube reactor, and a catalyst feed port (701) for introducing an isomerization catalyst is provided on a feed pipe connecting the isomerization reactor (7) and the first distillation tower (4), and a top discharge port of the isomerization reactor (7) is connected to a middle feed port of the second distillation tower (8); The second distillation tower (8) is a vacuum distillation tower, a second thermosyphon reboiler (10) is installed at the bottom of the second distillation tower (8), the top discharge port of the second distillation tower (8) is connected to the feed port of the second condenser (9), the second condenser (9) is connected to the vacuum pump (13), the liquid phase discharge port of the second condenser (9) is divided into two branches: one branch is refluxed to the second distillation tower (8), and the other branch is connected to the feed port of the maleic anhydride storage tank (3), the feed port in the middle of the second distillation tower (8) is connected to the discharge port of the isomerization reactor (7), the discharge port in the middle of the second distillation tower (8) is connected to the feed port of the stripping tower (11), and the bottom discharge port of the second distillation tower (8) is divided into two branches: one branch is connected to the feed port of the second thermosyphon reboiler (10), and the other branch is used to extract heavy components; The product stripping tower (11) is an auxiliary device of the second distillation tower (8). The top outlet of the stripping tower (11) is refluxed to the second distillation tower (8). The bottom outlet of the product stripping tower (11) is divided into two branches: one branch is connected to the feed port of the third thermosyphon reboiler (12), and the other branch is used to produce the finished methyltetrahydrophthalic anhydride.
2. A continuous production device for preparing methyltetrahydrophthalic anhydride according to claim 1, characterized in that: The synthesis reactor (1) is a tubular reactor, each C5 feed pipe of which is provided with a small hole (105), and a baffle (106) is also provided inside the tubular reactor.
3. A continuous production device for preparing methyltetrahydrophthalic anhydride according to claim 2, characterized in that: A pressure relief valve (107) is installed on the pipeline connecting the synthesis reactor (1) and the first distillation tower (4).
4. A continuous production device for preparing methyltetrahydrophthalic anhydride according to claim 1, characterized in that: The discharge port of the first thermosyphon reboiler (6) is connected to the lower inlet of the first distillation tower (4); the discharge port of the second thermosyphon reboiler (10) is connected to the lower inlet of the second distillation tower (8); and the discharge port of the third thermosyphon reboiler (12) is connected to the lower inlet of the product stripping tower (11).
5. A continuous production device for preparing methyltetrahydrophthalic anhydride according to claim 1, characterized in that: The branch outlet for obtaining the methyltetrahydrophthalic anhydride finished product at the bottom outlet of the product stripping tower (11) is connected to the side feed port of the first thermosyphon reboiler (6), and the side outlet of the first thermosyphon reboiler (6) is used to obtain the finished product.