Reaction system for preparing cyclic ether polymer

Abstract

The utility model provides a reaction system for preparing cyclic ether polymer, which particularly comprises a tubular fixed bed reactor and a temperature control system, a plurality of reaction tubes are arranged in the tubular fixed bed reactor, internal parts for enhancing mass transfer and heat transfer of materials are arranged in the reaction tubes, and the tubular fixed bed reactor is divided into more than two independent areas by partition plates which are arranged perpendicular to the axial direction of the reaction tubes; the temperature control system comprises thermometers which are arranged in part or all of the reaction tubes and are used for measuring the temperatures of different axial positions of the reaction tubes, and a cooling medium which flows in the tubular fixed bed reactor and outside the reaction tubes; and the temperature control system regulates and controls the reaction temperature in the regional reaction tube by independently regulating the flow of the cooling medium in the specific region. According to the utility model, the use of an external circulation heat removal mode of the existing polymerization reactor can be avoided, a reaction system with higher polymer viscosity cannot be met, and the cyclic ether polymer with high conversion rate and low molecular weight distribution index can be prepared.

Description

Technical Field

[0001] The utility model belongs to the fields of polymer material synthesis and polymerization reaction control, and particularly relates to a reaction system for preparing cyclic ether polymers. Background Art

[0002] Cyclic ether compounds are excellent monomers for synthesizing heterochain polymer materials due to their easy polymerization, rich structures and functional groups. Cyclic ethers can undergo ring-opening polymerization (homopolymerization) to form aliphatic polyethers with different side groups, and can also copolymerize with homologous cyclic ether monomers to obtain polymers with more abundant side group compositions. Cyclic ethers can carry out random, alternating, block and other copolymerization reactions with many non-epoxy compounds such as cyclic esters, cyclic anhydrides, carbon dioxide and its derivatives to form polymers with a main chain structure significantly different from the side chain. Due to the advantages of uniform main chain structure, controllable molecular weight, degradability, etc., such polymers have developed rapidly. With the development of industry and society, the functions and qualities of various polymer materials are more refined, and it is of great significance to precisely control the structure and properties of cyclic ether polymers from the polymerization reaction system.

[0003] The ring-opening polymerization of cyclic ethers to generate various polyester and polyether compounds mainly initiates the ring-opening of cyclic ethers through specific catalysts and undergoes polymerization reactions. Due to the advantages of simple reactor structure and easy separation, heterogeneous fixed-bed reactors are widely used in actual production. According to the ring-opening polymerization reaction mechanism of cyclic ethers, the characteristics of the polymerization reaction are as follows:

[0004] 1. The polymerization reaction has many steps, a complex mechanism and many influencing factors. Generally, high-active species are generated by chain initiation, and then the polymerization reaction is completed through steps such as chain growth, chain transfer and chain termination. Side reactions such as accompanying reactions, random transfer between different active species, and even branching and crosslinking will occur during the whole process, which further increases the complexity of the reaction. In fact, the ring-opening polymerization of cyclic ethers generates a very large number of polymers with irregular structures, high molecular weights or low molecular weights, resulting in different molecular weights of the polymerization products and a widened molecular weight distribution. The residence time and reaction temperature of the reaction have important effects on the concentration of active species, reaction rate and polymerization direction during the reaction process, and thus affect performance indexes such as the conversion rate, viscosity, number-average molecular weight and molecular weight distribution index of the polymer.

[0005] 2. Most of the cyclic ether polymerizations are exothermic reactions, and the heat release is unstable, with a very large instantaneous heat release. The reaction temperature is one of the most important conditions affecting the polymerization reaction. Moreover, the polymer itself has a small thermal conductivity and poor heat transfer, making it difficult to control the temperature of the reactor. How to discharge the polymerization heat has become a difficult point in the industrial production of polymerization reactions. During the polymer synthesis reaction process, determining an appropriate reaction temperature is very crucial. In industrial production, the temperature difference across the bed layer of the fixed-bed reactor is the key index for controlling the reaction temperature.

[0006] In view of the characteristics of polymerization reactions, fixed-bed reactors or shell-and-tube reactors are commonly used in the prior art, but both have defects. One common type is the adiabatic fixed-bed reactor, in which the reactor cylinder is filled with catalyst particles. This is the most widely used reactor type, and heat is removed through an external circulation outside the reactor. Patent applications CN1390873A and CN1389493A both adopt this type of reactor. To ensure a small temperature difference in the bed layer, this method usually requires a large circulation rate. In addition to high energy consumption, it also leads to a shortened residence time of the reactants in the reactor, resulting in poor conversion rate, molecular weight distribution, and chromaticity of the polymer. It is impossible to balance product performance and temperature control simultaneously, limiting the scope of application. The other type is the shell-and-tube fixed-bed reactor, which is mostly used in highly exothermic reactions such as oxidation, nitration, and alkylation of low-viscosity systems. Heat exchange is carried out between the cooling medium and the material in the tubes, and the reaction temperature is stabilized by controlling the flow rate of the cooling medium. The inner diameter of the reaction tubes is usually small (≤50 mm), and the number can reach tens of thousands, but this also limits the production capacity. CN2764474Y discloses a shell-and-tube fixed-bed reactor, which is a conventional shell-and-tube reactor. The inner diameter of the reaction tube is only 40 mm and is used for the reaction of propylene oxidation to prepare propylene oxide. CN1736574A describes a shell-and-tube fixed-bed reactor. In this utility model, the tubes adopt a double-tube structure, and the catalyst is filled in the gap between the tubes. The cooling medium flows through the tube side of the inner tube and the shell side of the reactor at the same time to narrow the width of the laminar flow state to improve heat transfer and increase the heat transfer area. However, since the reactants generated by polymerization reactions usually have a high viscosity, the reactants are in a laminar flow on the tube wall of the reaction tube, with a low heat transfer coefficient, uneven heat transfer, lack of effective flow mixing in the radial direction, and uneven axial temperature distribution. The existing shell-and-tube reactors use the reactor shell as a whole, and the temperature of the cooling medium is a fixed value. Problems such as the uneven flow and temperature in the reaction tubes cannot be solved, and only the temperature of the cooling medium can be reduced as a whole, affecting the temperature of the entire reactor bed layer.

[0007] Therefore, there is a need in the art for a catalytic polymerization reaction system for exothermic reactions in high-viscosity material systems. Without affecting the residence time of the reaction materials in the reactor, this reaction system can solve the heat removal problem of polymerization reactions with low energy consumption, and accurately control the temperature of the reactor to eliminate local high temperatures, meeting the requirements for the fine production of high molecular polymer materials in view of the poor heat transfer and mass transfer effects caused by the high viscosity of the material system. Summary of the Invention

[0008] The object of the present invention is to provide a reaction system for preparing cyclic ether polymers.

[0009] The present utility model provides a polymerization reaction system for preparing cyclic ether polymers. The reaction system includes a shell-and-tube fixed-bed reactor. By adding a low-shear inner part into the reaction tubes, the flow pattern of the polymer fluid with a relatively high viscosity in the reaction tubes is changed, the radial flow mixing and heat transfer are enhanced, so that the materials in the near-wall area and the center of the reaction tubes are uniform, without affecting the properties of the polymers. The temperature control system in the present utility model is independently controlled according to the local high temperatures in each area, so as to achieve the overall axial temperature uniformity of the shell-and-tube fixed-bed reactor. It can also independently control the temperatures of each area of the shell-and-tube fixed-bed reactor according to process requirements without affecting the overall reaction conditions, reducing side reactions such as chain transfer and chain growth in the polymerization reaction, having a good reaction effect, meeting the needs of fine polymer production, with a good molecular weight distribution of the generated polymers, regular and uniform structures, and good properties.

[0010] In the first aspect of the present utility model, there is provided a reaction system, the reaction system including a shell-and-tube fixed-bed reactor and a temperature control system;

[0011] A plurality of reaction tubes are arranged inside the shell-and-tube fixed-bed reactor, and an inner part for enhancing the mass transfer and heat transfer of materials is arranged inside the reaction tubes. The shell-and-tube fixed-bed reactor is divided into two or more independent areas by a partition plate arranged perpendicular to the axial direction of the reaction tubes; the shell-and-tube fixed-bed reactor includes a shell, a cooling medium inlet and a cooling medium outlet arranged on the shell, and a cooling medium inlet and a cooling medium outlet are arranged on the shell of each area;

[0012] The temperature control system includes thermometers arranged in some or all of the reaction tubes for measuring the temperatures at different axial positions of the reaction tubes, and a cooling medium flowing in the external area of the reaction tubes inside the shell-and-tube fixed-bed reactor. The temperature control system adjusts the flow rate of the cooling medium in a specific area independently to control the reaction temperature inside the reaction tubes in this area. Description of the Drawings

[0013] Figure 1 is a schematic structural diagram of the reaction system in one or more embodiments of the present utility model; wherein, shell-and-tube fixed-bed reactor - 1, reaction raw material distributor - 2, reaction tube - 3, cooling medium outlet - 4a, cooling medium outlet - 4b, cooling medium outlet - 4c, cooling medium inlet - 5a, cooling medium inlet - 5b, cooling medium inlet - 5c, cooling medium cooler - 6, cooling medium circulation pump - 7, cooling medium elevated tank - 8, multi-point thermometer - 9, partition plate - 10, reaction raw material inlet - 12, polymer product outlet - 13.

[0014] Figure 2 is a schematic structural diagram of the double-stranded spiral ribbon inner part in one or more embodiments of the present utility model.

[0015] Figure 3 It is a schematic diagram of the installation positions of the reaction tube and the multi-point thermometer in one or more embodiments of the present utility model; among them, the reactor tube sheet - 11.

[0016] Figure 4 It is a schematic diagram of the temperature measurement positions of the multi-point thermometer in one or more embodiments of the present utility model.

[0017] Figure 5 It is a schematic diagram of the reaction tube in one or more embodiments of the present utility model. (a) is to design fins on the outer wall of the reaction tube, (b) is to design corrugated tubes inside the reaction tube, and (c) is to design baffle plates inside the reaction tube.

[0018] Figure 6 It is a schematic diagram of the reaction system of Comparative Example 1; among them, the reactor - 1', the feed distributor - 2', the feed inlet - 3', the discharge outlet - 4', the reactor circulation pump - 5', the circulation cooler - 6', the catalyst - 7', the multi-point thermometer - 9'.

[0019] Figure 7 It is a schematic diagram of the installation positions of three multi-point thermometers in the reactor of Comparative Example 1.

[0020] Figure 8 It is a schematic diagram of the temperature measurement positions of the multi-point thermometer of Comparative Example 1. Detailed implementation manners

[0021] To enable those skilled in the art to understand the features and effects of the present utility model, the following is a general description and definition of the terms and expressions mentioned in this article. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meanings understood by those skilled in the art for the present utility model. In case of conflict, the definitions in this specification shall prevail.

[0022] The theories or mechanisms described and disclosed in this article, whether right or wrong, shall not limit the scope of the present utility model in any way, that is, the content of the present utility model can be implemented without being limited by any specific theory or mechanism.

[0023] In this article, terms such as "comprising", "including", "containing" and similar terms cover the meanings of "consisting essentially of..." and "consisting of...". For example, when this article discloses that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" have been disclosed herein.

[0024] In this text, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or percentage range should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0025] In this text, unless otherwise specified, the percentage refers to the mass percentage, and the ratio refers to the mass ratio.

[0026] In this text, when describing the embodiments or examples, it should be understood that it is not used to limit the present utility model to these embodiments or examples. On the contrary, all alternatives, improvements, and equivalents of the methods and materials described in the present utility model can be covered within the scope defined by the present utility model.

[0027] In this text, for the sake of concise description, all possible combinations of all technical features in each embodiment or example are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as being within the scope described in this specification.

[0028] "Open pore rate" refers to the ratio of the total area of small holes on the belt-type internal component to the total surface area of the internal component, and its calculation formula is:

[0029]

[0030] wherein,

[0031] n is the number of small hole openings, d is the diameter of the small hole, and x is different L values;

[0032] f(x) is the belt curve function, N is the number of belt spirals, L is the length of the intersection of two spiral contours of the belt-type internal component, and W is the distance between the highest points of the spiral contours.

[0033] "Tube pitch" is the distance between the central axes of two adjacent reaction tubes.

[0034] "Bed temperature difference" refers to the temperature difference between the top and bottom ends of a shell-and-tube fixed-bed reactor. When only one temperature measurement point is set at the top of the shell-and-tube fixed-bed reactor, the temperature measured at this temperature measurement point is the top temperature. When multiple thermometers are set inside the shell-and-tube fixed-bed reactor and multiple temperature data are measured at the same height and different temperature measurement positions at the top, the top temperature is the average value of these temperature values. The bottom temperature can be obtained by the same method. The bed temperature difference is the difference between the top temperature and the bottom temperature.

[0035] "Belt length" refers to the length L of the intersection of two spiral contours of the belt-type internal component, and "belt width" W is the distance between the highest points of the spiral contours, asFigure 2 As shown, the ratio of the width to the length of the ribbon is W:L. In the ribbon-shaped internal member, the width of the ribbon is the same as the width of the internal member.

[0036] According to the mechanism of ring ether ring-opening polymerization, the polymerization reaction generally consists of multiple steps such as chain initiation, chain growth, chain transfer, and chain termination. The structure, concentration, etc. of the active species generated during the reaction are different due to differences in reaction conditions, resulting in an increase in side reactions, such as chain transfer between macromolecules, long-chain branching, disproportionation termination, etc., making the polymerization reaction process complex and the by-products increase, affecting performance indicators such as the conversion rate, viscosity, number-average molecular weight, and molecular weight distribution index of the polymerization product. According to the research results of reaction kinetics, a short residence time and unstable reaction temperature will lead to an increase in the content of active species in the reactor, which is more conducive to the occurrence of the chain transfer step, resulting in an increase in the content of polymers with irregular structures, an increase in the molecular weight and viscosity of the polymerization product, and a deterioration of the molecular weight distribution. Therefore, sufficient residence time and a stable and uniform reaction temperature are the key conditions for precisely controlling the ring ether polymerization reaction.

[0037] Reaction system

[0038] In order to solve the problems of non-uniform temperature inside the exothermic reaction reactor and poor mass and heat transfer of high-viscosity materials, the present utility model provides a reaction system with uniform and controllable temperature inside the reactor and good mass and heat transfer. The reaction system of the present utility model includes a shell-and-tube fixed-bed reactor and a temperature control system; a plurality of reaction tubes are arranged inside the shell-and-tube fixed-bed reactor, and an internal member for enhancing mass and heat transfer of the material is arranged inside the reaction tubes. The shell-and-tube fixed-bed reactor is divided into two or more independent regions by a partition plate arranged perpendicular to the axial direction of the reaction tubes; the temperature control system includes a thermometer for measuring the temperature at different axial positions of the reaction tubes arranged in some or all of the reaction tubes, and a cooling medium flowing in the external region of the reaction tubes inside the shell-and-tube fixed-bed reactor. The temperature control system adjusts the flow rate of the cooling medium in a specific region independently to control the reaction temperature inside the reaction tubes in this region.

[0039] In some embodiments, the shell-and-tube fixed-bed reactor and the reaction tubes can be placed horizontally (the axis of the tubes is parallel to the horizontal plane), or can be placed vertically (the axis of the tubes is perpendicular to the horizontal plane). Preferably, the shell-and-tube fixed-bed reactor and the reaction tubes are placed vertically. In some embodiments, the connection line of the centers of each cross-section of the tubes can be a straight line or a wavy line.

[0040] In some embodiments, a shell-and-tube fixed-bed reactor is provided with a plurality of reaction tubes, and the number of reaction tubes can be adjusted according to the production capacity. In some embodiments, the shell-and-tube reactor is provided with 2 - 100 tubes, preferably 5 - 70 tubes or 20 - 50 tubes, such as 7 tubes, 9 tubes, 11 tubes, 15 tubes, 20 tubes, 25 tubes, 30 tubes, 40 tubes, 50 tubes, 60 tubes, 70 tubes, or within the range formed by any two numerical values.

[0041] In some embodiments, a reactor tube sheet whose plane is perpendicular to the axis of the shell-and-tube fixed-bed reactor is provided inside the shell-and-tube fixed-bed reactor. The reactor tube sheet includes holes for the reaction tubes to pass through. As is generally understood by those skilled in the art, the reactor tube sheet can play a role in fixing the reaction tubes passing through its holes. The number of holes on the reactor tube sheet is the same as the number of reaction tubes.

[0042] The shell-and-tube fixed-bed reactor includes a shell, a cooling medium inlet and a cooling medium outlet provided on the shell, and each area of the shell is provided with a cooling medium inlet and a cooling medium outlet.

[0043] The reaction system of the present utility model further includes a feeder provided on one side of the feed inlet of the shell-and-tube fixed-bed reactor. In some embodiments, the feeder is a reaction raw material distributor. Preferably, the reaction system of the present utility model further includes a reaction raw material inlet connected to the feeder, and a pipeline connecting the reaction raw material inlet and the feeder.

[0044] In some embodiments, the reaction system of the present utility model further includes a polymerization product outlet provided at the bottom of the shell of the shell-and-tube fixed-bed reactor, and a pipeline connecting the shell of the shell-and-tube fixed-bed reactor and the polymerization product outlet.

[0045] In some embodiments, the cooling medium inlet of each area is provided at one end of the shell of the shell-and-tube fixed-bed reactor away from the feeder; the cooling medium outlet of each area is provided at one end of the shell of the shell-and-tube fixed-bed reactor close to the feeder.

[0046] In some embodiments, the temperature control system includes a cooling medium cooler, a cooling medium circulation pump, a cooling medium elevated tank, and pipelines through which the cooling medium flows. The pipelines through which the cooling medium flows include a pipeline connecting the cooling medium elevated tank and the cooling medium circulation pump, a pipeline connecting the cooling medium circulation pump and the cooling medium cooler, and a pipeline connecting the cooling medium cooler and the cooling medium inlet; the cooling medium outlet is connected to the pipeline connecting the cooling medium elevated tank and the cooling medium circulation pump through a first pipeline; the pipeline connecting the cooling medium circulation pump and the cooling medium cooler is connected to the pipeline connecting the cooling medium cooler and the cooling medium inlet through a second pipeline.

[0047] In some embodiments, a valve and a first controller for controlling the opening and closing of the valve are provided on the pipeline connecting the cooling medium cooler and the cooling medium inlet, and the first controller is connected to the thermometer through an electronic signal.

[0048] In some embodiments, a valve and a second controller for controlling the opening and closing of the valve are provided on the second pipeline, and the second controller is connected to the thermometer through an electronic signal.

[0049] One or more than two thermometers can be provided. Due to the high viscosity characteristics of the polymer, local high temperatures may occur at different positions during the reaction. Therefore, multiple thermometers can be provided at different positions on the cross-section of the reaction tube in the present utility model, and the temperatures at different positions along the axis of the reaction tube can be measured simultaneously. Preferably, more than two thermometers are provided, such as 3, 4, 5, 6, 7, 8, 9, 10.

[0050] In some embodiments, the maximum value of the axial temperature difference of the reaction tube measured by each thermometer is controlled by the temperature control system to be ≤5°C, such as ≤4°C, ≤3°C, ≤2°C, ≤1°C, ≤0.8°C, ≤0.5°C, ≤0.3°C, ≤0.2°C.

[0051] In some embodiments, the bed temperature difference is controlled by the temperature control system to be ≤3°C, such as ≤2°C, ≤1°C, ≤0.8°C, ≤0.5°C, ≤0.3°C. Preferably, the bed temperature difference is controlled by the temperature control system to be ≤0.2°C or ≤0.17°C.

[0052] In some embodiments, the shell of the shell-and-tube fixed bed reactor is a cylindrical barrel. The cylindrical barrel has upper and lower heads, and can be connected by welding or flange. In some embodiments, the inner diameter of the shell of the shell-and-tube fixed bed reactor is 200 - 10000 mm, such as 300 m, 400 m, 500 m, 800 m, 1000 m, 3000 m, 5000 m, 7000 m, 9000 m, or within the range composed of any two values.

[0053] In some embodiments, the inner diameter of the reaction tube is ≥50 mm, such as 80 mm, 100 mm, 200 mm, 300 mm, 500 mm, 700 mm, 900 mm, 1100 mm, 1300 mm, 1500 mm, 1700 mm, 1900 mm, or within the range composed of any two values. In some embodiments, the inner diameter of the reaction tube is 80 - 2000 mm, preferably 80 - 1000 mm or 80 - 500 mm.

[0054] In some embodiments, the ratio of the inner diameter of the shell to the inner diameter of the reaction tube is (5 - 100):1, such as 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, or within the range formed by any two values, preferably (10 - 80):1. In some embodiments, the ratio of the inner diameter of the shell to the inner diameter of the reaction tube is (5 - 50):1.

[0055] In some embodiments, the tube pitch of the reaction tube is 1 - 2 times the inner diameter of the reaction tube, such as 1.1 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, or within the range formed by any two values, preferably 1.2 - 1.5 times.

[0056] The number of said regions is 2 - 10, such as 3, 4, 5, 6, 7, 8, 9, 10, or within the range formed by any two values, preferably 3 - 6. In some embodiments, the shell-and-tube fixed-bed reactor is divided into three or four regions by partitions arranged perpendicular to the axial direction of the reaction tubes.

[0057] In some embodiments, the internal member is a ribbon-type internal member, preferably a spiral ribbon-type internal member, more preferably a double-twisted spiral ribbon-type internal member. This internal member is a low-shear-force ribbon-type internal member, which does not change the properties of the polymerization product. Installing the internal member of the present invention in the reaction tube can improve the mass transfer and heat transfer of high-viscosity materials. In some embodiments, the length of the ribbon of the ribbon-type internal member is 600 - 1500 mm, such as 800 mm, 1000 mm, 3000 mm, 5000 mm, 7000 mm, 9000 mm, 1100 mm, 1300 mm, 1500 mm, or within the range formed by any two values. In some embodiments, the ratio of the width of the ribbon to the length of the ribbon of the ribbon-type internal member is 1:(5 - 20), such as 1:5, 1:10, 1:15, 1:16, 1:18, 1:20, or within the range formed by any two values.

[0058] In some embodiments, 1 or more than 2 internal members are arranged in the reaction tube.

[0059] In some embodiments, the width of the internal member is 40 - 300 mm, such as 50 mm, 60 mm, 80 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm, or within the range formed by any two values.

[0060] In some embodiments, the ratio of the width of the inner component to the inner diameter of the reaction tube is 1:(1 - 100), such as 1:1, 1:3, 1:5, 1:10, 1:20, 1:50, 1:80, 1:100, or within the range formed by any two numerical values.

[0061] In some embodiments, through holes with a diameter of 1 - 5 mm are provided on the inner component. For example, the diameter of the through holes can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or within the range formed by any two numerical values.

[0062] In some embodiments, the porosity of the inner component is 5% - 50%, such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or within the range formed by any two numerical values.

[0063] In some embodiments, the length of the inner component is 0.5 - 1 times the length of the reaction tube, such as 0.6 times, 0.8 times, 0.9 times, 1 time; preferably, the length of the inner component is the same as the length of the reaction tube.

[0064] In the present utility model, by arranging an inner component in the reaction tube, the material flow in the reaction tube generates a spiral flow along the tie, divides the flow channel, changes the flow state of the fluid, and the material can also form a turbulent flow in the tube wall region, increasing the Reynolds number to more than 4000, greatly enhancing the mixing and heat transfer of the reaction tube material in the radial direction, thereby improving the efficiency of the polymerization reaction and reducing the production energy consumption. In order to reduce the shear force of the flow channel division and avoid affecting the polymer performance, small holes with a diameter of 1 - 5 mm are opened on the inner component, and the small holes are evenly distributed on the tie.

[0065] In some embodiments, the reaction tubes are evenly distributed at equal intervals inside the shell-and-tube fixed-bed reactor, which is more conducive to the heat transfer of the reaction tubes.

[0066] In some embodiments, the reaction tubes equipped with thermometers are evenly distributed inside the shell-and-tube fixed-bed reactor, which can more accurately monitor the temperature at each position inside the shell-and-tube fixed-bed reactor.

[0067] In some embodiments, the thermometer is a multi-point thermometer, and 2 - 10 temperature measurement points are distributed along the axial direction of the reaction tube. In some embodiments, the multi-point thermometer has 3, 4, 5, 6, 7, 8, 9, or 10 temperature measurement points distributed along the axial direction of the reaction tube.

[0068] In some embodiments, the reaction tube is a smooth tube or a reaction tube provided with a heat transfer enhancement structure. A smooth tube refers to a smooth straight tube without other structures. As Figure 5 shown, the reaction tube provided with a heat transfer enhancement structure can be (a) a reaction tube with fins designed on the outer wall, (b) a reaction tube with corrugated tubes designed inside, (c) a reaction tube with baffle plates designed inside.

[0069] In some embodiments, during the operation of the reaction system of the present utility model, a solid catalyst is filled in the reaction tube.

[0070] Method

[0071] The present utility model provides a reaction system for the polymerization reaction of a heterogeneous catalytic system, which can enhance the radial mass transfer and mixing of a highly viscous polymerization reaction system and improve the heat transfer coefficient in the reaction tube. The temperatures in different regions of the shell-and-tube fixed-bed reactor can be independently controlled to eliminate local high temperatures without affecting the overall reaction condition of the shell-and-tube fixed-bed reactor, realizing precise control of the temperature of the shell-and-tube fixed-bed reactor, and further controlling the indexes of the polymer (conversion rate, viscosity, number-average molecular weight, molecular weight distribution index, etc.). Therefore, the present utility model also provides a method for preparing a cyclic ether polymer by using the reaction system of the present utility model, including the steps of adding a raw material containing a cyclic ether compound into the reaction tube for polymerization reaction, and independently controlling the flow rate of the cooling medium in each region through a temperature control system to control the temperature difference of the bed layer ≤ 3°C.

[0072] In some embodiments, the cooling medium can be selected from one or more of water and ethylene glycol. In some embodiments, the cooling medium is water and ethylene glycol. When the cooling medium is water and ethylene glycol, the mass fraction of ethylene glycol in the cooling medium is 20 - 40%, preferably 25 - 35%.

[0073] In some embodiments, the catalyst is a solid catalyst capable of catalyzing the polymerization of cyclic ether compounds.

[0074] In some embodiments, the reaction temperature is 20 - 150°C, such as 30°C, 40°C, 50°C, 60°C, 70°C, 90°C, 110°C, 130°C, or within the range composed of any two values, preferably 30 - 120°C or 40 - 60°C.

[0075] In some embodiments, the reaction pressure is 0.01 - 1.0 MPaG, such as 0.02 MPaG, 0.04 MPaG, 0.06 MPaG, 0.08 MPaG, 0.1 MPaG, 0.2 MPaG, 0.3 MPaG, 0.4 MPaG, 0.6 MPaG, 0.8 MPaG, or within the range composed of any two values, preferably 0.05 - 0.6 MpaG, 0.05 - 0.1 MPaG, or 0.2 - 0.3 MPaG.

[0076] The maximum value of the temperature difference in the bed layer is controlled by the temperature control system to be ≤ 3°C, such as ≤ 3°C, ≤ 2°C, ≤ 1°C, ≤ 0.8°C, ≤ 0.6°C, ≤ 0.5°C, ≤ 0.3°C, ≤ 0.2°C, ≤ 0.17°C, preferably ≤ 0.5°C. The reaction system of the present utility model can precisely regulate the temperature of each region, control the maximum value of the temperature difference in the bed layer within a certain range, and the polymerization reaction can adjust the temperature in the shell-and-tube fixed-bed reactor as needed.

[0077] In some embodiments, the polymerization reaction is a reaction for preparing a cyclic ether polymer by catalytic polymerization of a cyclic ether.

[0078] In some embodiments, the cyclic ether compound is an optionally substituted 3- to 8-membered cyclic ether compound; preferably, the cyclic ether compound is selected from one or more of ethylene oxide, propylene oxide, tetrahydrofuran, and cyclohexene oxide.

[0079] As used herein, "optionally" or "optional" means that the subsequent described event or condition may or may not occur, and the description includes both the occurrence and non-occurrence of the event or condition. For example, "optionally substituted 3- to 8-membered cyclic ether compound" means that the cyclic ether compound is either substituted or unsubstituted, and the description includes both the substituted cyclic ether compound and the unsubstituted cyclic ether compound. The "optional" substituents described in the present utility model are selected from C1-C4 alkyl, C2-C4 alkenyl, C2-C4 alkynyl, C1-C4 alkoxy, halogen, halo-C1-C4 alkyl, halo-C2-C4 alkenyl, halo-C2-C4 alkynyl, cyano, carboxyl, hydroxyl, nitro, azide, aldehyde, optionally substituted C6-C10 aryl, optionally substituted 5- to 7-membered heteroaryl, optionally substituted C5-C7 cycloalkyl, and optionally substituted 5- to 7-membered heterocyclic group. In some embodiments, the optionally substituted 3- to 8-membered cyclic ether compound is a 3- to 8-membered cyclic ether compound optionally substituted by C1-C4 alkyl.

[0080] As used herein, the term "substituted", whether or not preceded by the term "optionally" (i.e., equivalent to substituted or unsubstituted), means that one or more hydrogens of a specified group or moiety are replaced by a "suitable substituent". In this text, the number of substituents can be one or more, i.e., 1, 2, 3, 4, 5 or 6 or more, depending on the group being substituted and the nature of the substituent. For example, when the substituent of an ethyl group is a halogen, depending on the structure of the group being substituted, this group can be substituted by 1, 2, 3, 4 or 5 substituents, such as trifluoroethyl, pentafluoroethyl, etc. In some embodiments, the number of the substituents is 1, 2 or 3. In some embodiments, the number of the substituents is 1 or 2. In some embodiments, the number of the substituents is 1. It will be understood that "substituted" or "substituted by" includes the implicit condition that such substitution occurs according to the allowed valence of the substituting atom and results in a stable or chemically viable compound, e.g., a compound that does not spontaneously undergo transformation, such as by rearrangement, cyclization, elimination, etc. Unless otherwise specified, an "optionally substituted" group can have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure can be substituted by more than one substituent selected from the specified group, the substituents can be the same or different at each position. Those skilled in the art will understand that, if appropriate, the substituent itself can be substituted. Unless specifically designated as "unsubstituted", chemical moieties mentioned herein should be understood to include substituted variants. For example, the mention of a "cyclic ether compound" or moiety implicitly includes unsubstituted cyclic ether compounds and substituted derivatives.

[0081] In some embodiments, the cyclic ether polymer is a polymer polymerized from a cyclic ether compound as the main monomer, wherein the mass of the cyclic ether compound can account for more than 80% of the total mass of the raw materials, such as more than 90%, more than 95%, more than 98%, more than 99%. In some embodiments, the raw materials further include comonomers. The mass ratio of the cyclic ether compound to the comonomer is (10 - 200):1, such as 30:1, 40:1, 50:1, 80:1, 100:1, 150:1, 180:1, 200:1, or within the range composed of any two values. Preferably, the mass ratio of the cyclic ether compound to the comonomer is (30 - 80):1.

[0082] The comonomer can be selected from one or more of acid anhydrides, cyclic acid anhydrides, cyclic esters, carbon dioxide, polyols and polycarboxylic acids. In some embodiments, the comonomer is selected from one or more of acid anhydrides, cyclic acid anhydrides, polyols and polycarboxylic acids. In some embodiments, the comonomer is selected from acid anhydrides and / or polyols. Preferably, the acid anhydride is acetic anhydride. Preferably, the polyol is ethylene glycol.

[0083] Examples of the cyclic ether polymer include but are not limited to polyether polyesters, polyether polyols, etc.

[0084] In this text, an acid anhydride refers to a compound formed by the dehydration condensation of carboxyl groups between multiple (e.g., two) carboxylic acid molecules to form an acid anhydride group. In this text, multiple means two or more, such as two, three, four, five, six. The acid anhydride can be a C2-C10 acid anhydride, such as C2 acid anhydride, C3 acid anhydride, C4 acid anhydride, C5 acid anhydride, C6 acid anhydride, C7 acid anhydride, C8 acid anhydride, C9 acid anhydride, C10 acid anhydride. Usable acid anhydrides include but are not limited to acetic anhydride, propionic anhydride, etc.

[0085] In this text, a cyclic acid anhydride refers to a compound formed by the dehydration condensation of carboxyl groups within a single carboxylic acid molecule containing multiple (e.g., two) carboxyl groups to form an acid anhydride group. The cyclic acid anhydride can be a 4-8 membered cyclic acid anhydride, such as a 4 membered cyclic acid anhydride, 5 membered cyclic acid anhydride, 6 membered cyclic acid anhydride, 7 membered cyclic acid anhydride, 8 membered cyclic acid anhydride.

[0086] In this text, a cyclic ester is a compound having an ester bond on the ring. The cyclic ester can be a 4-8 membered cyclic ester, such as a 4 membered cyclic ester, 5 membered cyclic ester, 6 membered cyclic acid anhydride, 7 membered cyclic ester, 8 membered cyclic ester.

[0087] In this text, a polyol refers to an alcohol containing multiple hydroxyl groups, including but not limited to diols, triols, etc. The polyol can be a C2-C10 polyol, such as C2 polyol, C3 polyol, C4 polyol, C5 polyol, C6 polyol, C7 polyol, C8 polyol, C9 polyol, C10 polyol. Usable polyols include but are not limited to ethylene glycol, propylene glycol, glycerol, etc.

[0088] In this text, a polycarboxylic acid refers to a carboxylic acid containing multiple carboxyl groups, including but not limited to dicarboxylic acids, tricarboxylic acids, etc. The polycarboxylic acid can be a C2-C10 polycarboxylic acid, such as C2 polycarboxylic acid, C3 polycarboxylic acid, C4 polycarboxylic acid, C5 polycarboxylic acid, C6 polycarboxylic acid, C7 polycarboxylic acid, C8 polycarboxylic acid, C9 polycarboxylic acid, C10 polycarboxylic acid.

[0089] In some embodiments, the molecular weight distribution index of the cyclic ether polymer ≤ 2, such as ≤ 1.9 or ≤ 1.8.

[0090] In some embodiments, the conversion rate of the polymerization reaction ≥ 65%, such as ≥ 66%, ≥ 67% or ≥ 68%.

[0091] In some embodiments, the Reynolds number of the fluid in the reaction tube is 2,000 - 25,000, such as 2,200, 3,000, 4,300, 4,500, 4,600, 4,680, 5,000, 8,000, 10,000, 15,000, 20,000, 25,000, or within the range between any two values. In some embodiments, the Reynolds number of the fluid in the reaction tube is 4,000 - 25,000. Preferably, the Reynolds number of the fluid in the reaction tube is 3,000 - 20,000, 4,000 - 10,000, 4,500 - 8,000, or 4,600 - 8,000.

[0092] In some embodiments, the Nusselt number of the fluid in the reaction tube is 80 - 1,000, such as 80, 100, 120, 140, 150, 200, 400, 800, 1,000, or within the range between any two values. Preferably, the Nusselt number of the fluid in the reaction tube is 120 - 500.

[0093] In this article, the Reynolds number and the Nusselt number are simulated by CFD software. As is known to those skilled in the art, although there are empirical calculation formulas for the Reynolds number and the Nusselt number, there are certain deviations in this method, and the Reynolds number and the Nusselt number obtained by simulating with CFD software are relatively more accurate.

[0094] Application

[0095] The present utility model provides the application of the reaction system of the present utility model in the reaction of high-viscosity materials. The reaction system of the present utility model is as described in any one of the embodiments herein.

[0096] In some embodiments, the reaction of high-viscosity materials is a polymerization reaction of a raw material containing a cyclic ether compound. The polymerization reaction of a raw material containing a cyclic ether compound is as described in any one of the embodiments herein.

[0097] In some embodiments, the viscosity of the high-viscosity material is ≥50 cp, such as ≥80 cp, ≥100 cp, ≥200 cp, ≥300 cp, ≥400 cp, ≥500 cp, ≥600 cp, ≥700 cp, ≥800 cp, ≥900 cp, ≥1,000 cp.

[0098] Due to the characteristics of easy polymerization, rich structure and functional groups of heterochain polymer materials, they have become excellent monomers for synthesizing polymer materials. In recent years, cyclic ether polymers have received extensive attention and rapid development in industrial applications. Modifying the properties of cyclic ether polymers through catalytic polymerization has become a research hotspot. The industrial control scheme of the cyclic ether ring-opening polymerization reaction system has a significant impact on the properties of the polymer. By precisely controlling process conditions such as the reaction temperature and the temperature difference of the bed layer, polymers with good properties can be obtained.

[0099] The utility model provides a reaction system for the polymerization of cyclic ether compounds, which can realize accurate control of polymer properties. The catalytic polymerization reaction system has important application prospects.

[0100] Due to the advanced nature of the technical solution of the utility model, the technology has broad application prospects in the field of synthetic polymer materials. For example, in industries such as plastics, rubber, coatings, and adhesives, cyclic ether polymers can be modified by catalytic polymerization to improve the performance and quality of the products. In addition, the technology can also be applied to medical devices, electronic materials, environmental protection and other fields to meet the needs of polymer materials in different application scenarios.

[0101] With the development of industry and technological progress, the requirements for functional applications are getting higher and higher, and the demand for various polymer materials is also growing further. Therefore, the technical solution of modifying the properties of cyclic ether polymers through catalytic polymerization has a broad market demand. The application prospects of this technology are very broad, and it is expected to achieve major breakthroughs and application value in many fields.

[0102] The utility model has the following beneficial effects:

[0103] (1) For polymer systems with high viscosity, low shear force internals are added to the reaction tube to enhance radial flow mixing, so that turbulence is formed near the wall of the reaction tube, which enhances the mixing and heat transfer of the medium in the reaction tube without affecting the performance of the polymerization product. With lower energy consumption and without changing the residence time of the reactor, the reaction efficiency is improved.

[0104] (2) The temperature control system of the reaction system of the utility model is independently controlled according to the local high temperature of each area, so as to achieve uniform axial temperature of the entire reactor.

[0105] (3) The utility model realizes independent control of the temperature of each zone of the reactor according to the process requirements without affecting the reaction conditions in other zones, thereby reducing side reactions in the polymerization reaction such as chain transfer and chain growth, having good reaction effects and product performance, and being able to meet the needs of refined polymer production.

[0106] In summary, compared with the prior art, the utility model has the advantages of better temperature control, quality control of polymerization products, reduced energy consumption and expanded production scale, etc. It can avoid the use of the external circulation heat removal method of the existing polymerization reactor, and the conventional tubular reactor cannot meet the reaction system with high polymer viscosity, thereby achieving the goal of refined production of polymers and obtaining cyclic ether polymers with high conversion rate and low molecular weight distribution index.

[0107] The present utility model will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present utility model and not to limit the scope of the present utility model. The experimental methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0108] Equipment Example 1

[0109] As Figure 1 and 3 shown, this equipment example provides a system for preparing cyclic ether polymers, including a shell-and-tube fixed-bed reactor 1 and a temperature control system. The shell-and-tube fixed-bed reactor 1 includes a cylindrical shell, a reactor tube sheet 11 with 7 holes arranged parallel to the horizontal plane in the shell, 7 reaction tubes 3 passing through the holes of the reactor tube sheet 11 and arranged parallel to each other with a double-stranded spiral ribbon-type internal member installed inside each, 3 multi-point thermometers 9 in 3 reaction tubes 3 arranged in different regions, a reaction raw material distributor 2 arranged at the upper part of the shell, a reaction raw material inlet 12 connected to the reaction raw material distributor 2, and a polymerization product outlet 13 arranged at the bottom of the shell. The setting positions of the reactor tube sheet 11 with 7 holes and the multi-point thermometers 9 are as Figure 3 shown, where each circle represents 1 reaction tube 3, and the black dots represent that a multi-point thermometer is arranged in the reaction tube. The temperatures measured by the 3 multi-point thermometers are respectively denoted as TA, TB, and TC. As Figure 2 shown, the width of the double-stranded spiral ribbon is 60 mm, the length is 8000 mm, the length of the ribbon is 1000 mm, and the ribbon has small holes with an opening ratio of 10%. The inner diameter of the shell of the shell-and-tube fixed-bed reactor 1 is 400 mm, the tube pitch of the reaction tubes is 100 mm, and the shell-and-tube fixed-bed reactor 1 and the reaction tubes 3 are both arranged perpendicular to the horizontal plane. The shell-and-tube fixed-bed reactor 1 is axially divided into three regions by two partitions 10, namely the upper (I) region, the middle (II) region, and the lower (III) region. The size of each reaction tube 3 is As Figure 4 shown, the multi-point thermometer 9 is used to measure the temperatures at different axial positions inside the reaction tube where it is located, and the temperature values TA-1, TA-2, TA-3, TA-4, TA-5, TA-6, TA-7, TA-8, TA-9, TA-10 at different depths can be measured. TA-1 is located at the top of the reaction tube, and TA-10 is located at the bottom of the reaction tube. TA-1, TA-2, TA-3 are located in the upper (I) region, TA-4, TA-5, TA-6, TA-7 are located in the middle (II) region, and TA-8, TA-9, TA-10 are located in the lower (III) region.

[0110] The temperature control system includes a high-level cooling medium tank 8, a cooling medium circulation pump 7, a cooling medium cooler 6, shell-side cooling medium inlets 5a, 5b, 5c and shell-side cooling medium outlets 4a, 4b, 4c. The temperature control system also includes pipelines connecting the high-level cooling medium tank 8 and the cooling medium circulation pump 7, pipelines connecting the cooling medium circulation pump 7 and the cooling medium cooler 6, and pipelines connecting the cooling medium cooler 6 and the shell-side cooling medium inlets 5a, 5b, 5c. The shell-side cooling medium inlets 5a, 5b, 5c and the shell-side cooling medium outlets 4a, 4b, 4c are arranged on the shell of the shell-and-tube reactor 1. In the upper (I) region of the shell-and-tube reactor, an upper shell-side cooling medium inlet 5a and an upper shell-side cooling medium outlet 4a are provided; in the middle (II) region of the shell-and-tube reactor, a middle shell-side cooling medium inlet 5b and a middle shell-side cooling medium outlet 4b are provided; in the lower (III) region of the shell-and-tube reactor, a lower shell-side cooling medium inlet 5c and a lower shell-side cooling medium outlet 4c are provided. The shell-side cooling medium outlets 4a, 4b, 4c are connected to the pipeline connecting the high-level cooling medium tank 8 and the cooling medium circulation pump 7 through pipelines. The cooling medium cooler 6 is connected to the shell-side cooling medium inlets 5a, 5b, 5c through pipelines, and valves and a controller for controlling the opening and closing of the valves are provided on this pipeline. The controller is connected to a multi-point thermometer 9. Specifically, the valve controller on the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5a is connected to the temperature TA-9 on the multi-point thermometer 9 through an electronic signal; the valve controller on the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5b is connected to the temperature TA-6 on the multi-point thermometer 9 through an electronic signal; the valve controller on the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5c is connected to the temperature TA-3 on the multi-point thermometer 9 through an electronic signal. The pipeline connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 is connected to the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlets 5a, 5b, 5c through pipelines, and valves and a controller for controlling the opening and closing of the valves are provided on this pipeline (the pipeline for connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 and the pipeline for connecting the cooling medium cooler 6 and the shell-side cooling medium inlets 5a, 5b, 5c). The controller is connected to a multi-point thermometer 9.Specifically, the pipeline connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 is connected to the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5a through a pipeline. The valve controller on this pipeline (the pipeline for connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 and the pipeline for connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5a) is connected to the temperature TA-9 on the multi-point thermometer 9 through an electronic signal; the pipeline connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 is connected to the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5b through a pipeline. The valve controller on this pipeline (the pipeline for connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 and the pipeline for connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5b) is connected to the temperature TA-6 on the multi-point thermometer 9 through an electronic signal; the pipeline connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 is connected to the pipeline connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5c through a pipeline. The valve controller on this pipeline (the pipeline for connecting the cooling medium circulation pump 7 and the cooling medium cooler 6 and the pipeline for connecting the cooling medium cooler 6 and the shell-side cooling medium inlet 5c) is connected to the temperature TA-3 on the multi-point thermometer 9 through an electronic signal.

[0111] This reaction system is used for exothermic reactions. When the local temperature in the reaction tube overheats, the temperature at a specific position can be controlled through the temperature control system. When TA-3 exceeds the set reaction temperature, this reaction system can automatically control the opening and closing degree of the valve according to the temperature signal, thereby adjusting the flow rate of the cooling medium entering the upper (I) region. When TA-6 exceeds the set reaction temperature, this reaction system can automatically control the opening and closing degree of the valve according to the temperature signal, thereby adjusting the flow rate of the cooling medium entering the middle (II) region. When TA-9 exceeds the set reaction temperature, this reaction system can automatically control the opening and closing degree of the valve according to the temperature signal, thereby adjusting the flow rate of the cooling medium entering the lower (III) region.

[0112] Comparative equipment example 1

[0113] Comparative equipment example 1 is a traditional fixed-bed reactor, which requires external circulation cooling of the reaction liquid outside the reactor during the reaction process. As Figure 6As shown in the figure, Comparative Equipment Example 1 includes a reactor 1', a feed distributor 2' provided at the top of the reactor 1', three multi-point thermometers 9' provided inside the reactor 1', a catalyst 7' provided inside the reactor 1', a feed inlet 3', a discharge outlet 4', a reactor circulation pump 5', a circulation cooler 6', a pipe connecting the bottom outlet of the reactor 1' to the reactor circulation pump 5', a pipe connecting the reactor circulation pump 5' to the circulation cooler 6', and a pipe connecting the circulation cooler 6' to the feed distributor 2'. The feed inlet 3' is connected to the pipe connecting the bottom outlet of the reactor 1' to the reactor circulation pump 5' through a pipe, and a pipe connected to the discharge outlet 4' is also provided on the pipe connecting the bottom outlet of the reactor 1' to the reactor circulation pump 5'. The inner diameter of the reactor 1' is 400 mm, and the height of the cylinder body is 8000 mm.

[0114] Three multi-point thermometers are used to measure 10 temperature data in the axial direction at different positions inside the fixed-bed reactor (as Figure 7 shown, the temperature values measured by the three multi-point thermometers are TA', TB', and TC' respectively). For example, as Figure 8 shown, the 10 temperature values are TA'-1, TA'-2, TA'-3, TA'-4, TA'-5, TA'-6, TA'-7, TA'-8, TA'-9, and TA'-10 respectively. The setting positions of TA', TB', TC', TA'-1, TA'-2, TA'-3, TA'-4, TA'-5, TA'-6, TA'-7, TA'-8, TA'-9, and TA'-10 in the reactor 1' are the same as the setting positions of TA, TB, TC, TA-1, TA-2, TA-3, TA-4, TA-5, TA-6, TA-7, TA-8, TA-9, and TA-10 in the shell-and-tube fixed-bed reactor 1 of Equipment Example 1.

[0115] A valve and a valve controller for controlling the valve are provided on the pipe connecting the circulation cooler 6' to the feed distributor 2'. The valve controller is connected to the temperature of the multi-point thermometer 9' (TA', TB', or TC', and TA', TB', and TC' are the average values of the temperature values of 10 temperature measurement points of their respective multi-point thermometers) through an electronic signal. When TA' exceeds the set reaction temperature, the reaction system can automatically control the opening and closing degree of the valve according to the temperature signal, thereby adjusting the circulation amount of the reaction liquid.

[0116] Comparative Equipment Example 2

[0117] The only difference from Equipment Example 1 is that no internal parts are provided inside the reaction tube.

[0118] The temperatures measured by three multi-point thermometers are TA”, TB”, and TC” respectively. The temperatures measured axially by the multi-point thermometer with the measured temperature of TA” are TA”-1, TA”-2, TA”-3, TA”-4, TA”-5, TA”-6, TA”-7, TA”-8, TA”-9, and TA”-10 respectively.

[0119] Example 1

[0120] In this example, a reaction system of Equipment Example 1 is used to prepare a cyclic ether polymer.

[0121] Step 1: Install the reaction system according to the process of Equipment Example 1, dry the entire system, and take samples for analysis at the top of the shell-and-tube fixed-bed reactor 1 until the dew point of the entire system is monitored at -40°C.

[0122] Step 2: Purchase a commercially available solid catalyst (Clariant Chemical, K306) externally. The catalyst is spherical with a diameter Fill each reaction tube, and after completion of filling, replace the entire system with nitrogen. Take samples for analysis at the top of the shell-and-tube fixed-bed reactor 1, and the oxygen content ≤ 10 ppm.

[0123] Step 3: Use a 25 wt% ethylene glycol - aqueous solution as the cooling medium in the temperature control system. The temperature at which the cooling medium enters the shell-and-tube fixed-bed reactor 1 is controlled at 40°C. The cooling medium heat exchanger 6 uses circulating water (inlet water 31°C, return water 39°C). Set the temperatures of the three regions of the reaction system to be 50°C, and the flow rate of the cooling medium is stable; the pressure of the reaction tube is set at 0.3 MPaG.

[0124] Step 4: Add 1000 kg of tetrahydrofuran, 20 kg of acetic anhydride, and 10 kg of propylene oxide according to a mass ratio of 100:2:1, and feed them into the reaction system until all reaction tubes are filled. After stopping feeding for 4 hours, the reaction system continuously feeds and discharges materials.

[0125] Step 5: Control the temperatures of each measurement point of the multi-point thermometer to be within the range of 50 ± 0.5°C, and record the temperatures of 10 temperature measurement points (1#, 2#, 3#, 4#, 5#, 6#, 7#, 8#, 9#, 10#) of the three multi-point thermometers (for example, the thermometer measuring TA measures TA-1, TA-2, TA-3, TA-4, TA-5, TA-6, TA-7, TA-8, TA-9, TA-10 respectively at the temperature measurement positions 1#, 2#, 3#, 4#, 5#, 6#, 7#, 8#, 9#, 10#). Calculate its average temperature, maximum temperature difference, and total bed temperature difference. The data is shown in Table 1. Automatically control the cooling medium flow control valves in the three regions of the reactor, and record the flow rates of the cooling medium in each region. The flow rates of the cooling medium in the three regions and the total flow rate of the cooling medium are shown in Table 2.

[0126] Step 6: After continuous feeding for 8 hours, sample and analyze.

[0127] Comparative Example 1

[0128] Using the same reaction conditions as in Example 1, the reaction was carried out using the reaction system of Comparative Equipment Example 2. After the reactor was filled, the reaction solution was circulated in a large loop, and the circulation rate of the reaction solution was controlled automatically. Record the circulation rate of the reaction solution and the temperature measured by the multi-point thermometer at multiple points. The data are shown in Table 1-2.

[0129] Comparative Example 2

[0130] Using the same reaction conditions as in Example 1, the reaction was carried out using the reaction system of Comparative Equipment Example 2. Record the flow rates of TA”-1, TA”-2, TA”-3, TA”-4, TA”-5, TA”-6, TA”-7, TA”-8, TA”-9, TA”-10, and the cooling medium, as shown in Table 1-2.

[0131] Table 1

[0132]

[0133]

[0134] "Average temperature" refers to the average of the temperatures obtained at different temperature measurement positions of the same multi-point thermometer. For example, the average of the temperatures measured by the multi-point thermometer with temperature measurement TA at positions 1# to 10#.

[0135] "Maximum temperature difference" refers to the maximum temperature difference of the temperatures obtained at different temperature measurement positions of the same multi-point thermometer. For example, for the multi-point thermometer with temperature measurement TA, the highest temperature measured at positions 1# to 10# is TA max , the lowest temperature is TA min , and the maximum temperature difference = TA max - TA min .

[0136] "Bed temperature difference" refers to the temperature difference between the top and bottom of the reaction tube, which is the temperature difference between the temperatures measured at the 10# temperature measurement point and the 1# temperature measurement point. The temperature at the 10# temperature measurement point is the average of the temperatures measured by three multi-point thermometers at 10#, and the temperature at the 1# temperature measurement point is the average of the temperatures measured by three multi-point thermometers at 1# (for example, the temperature at the 1# temperature measurement point is the average of TA-1, TB-1, and TC-1).

[0137] Table 2

[0138] Example 1 Comparative Example 1 Comparative Example 2 Cooling medium flow rate in Region I 5.5 - 5.8 Cooling medium flow rate in Region II 6.2 - 6.5 Cooling medium flow rate in Region III 5.8 - 6.0 Total cooling medium flow rate 17.5 23 17.8 Reaction liquid circulation volume - 200 -

[0139] The products after the reactions of Example 1 and Comparative Examples 1-2 were tested and analyzed. The conversion rate, number-average molecular weight, viscosity, and molecular weight distribution index are shown in Table 3.

[0140] Table 3

[0141]

[0142]

[0143] The flow rate (the flow rate of the reaction liquid is the total volume of the reaction liquid for Example 1 and Comparative Example 2, and the flow rate of Comparative Example 1 is the circulation volume of the reaction liquid), pressure drop (the pressure difference between the raw material inlet and the raw material outlet), temperature (the average value of the temperatures measured at all temperature measurement points in the reaction system), and internal component boundary conditions (the length, width, and thickness of the internal component) of the reaction systems of Example 1 and Comparative Examples 1-2 were measured by conventional methods in the art, and were used to simulate and verify the fluid conditions through CFD software, as shown in Table 4. Among them, Re represents the Reynolds number, which is a characterization of the fluid flow condition. Nu represents the Nusselt number, which is a parameter characterizing the intensity of convective heat transfer. It can be seen from Table 4 that the results of the CFD simulation verification of Example 1 are consistent with the results of the reaction test, and the convective heat transfer intensity of Example 1 is much higher than that of Comparative Examples 1-2.

[0144] Table 4

[0145]

[0146] According to the reactor temperature conditions in Table 1 and the product analysis in Table 3, it can be seen that due to the good heat transfer and mass transfer effects, the overall temperature of Example 1 is uniform, and the temperature difference is relatively small both radially and axially. The molecular weight distribution of the generated polymer is also the best. Under the same feeding conditions, it shows excellent performance. At the same time, the simulation in the reaction tube by CFD also verifies this result.

[0147] Calculation of conversion rate = mass of polymer in product / total amount of raw materials × 100%;

[0148] The mass of the polymer is the weight of the polymer obtained after rotary evaporation under the conditions of -80 kPaG and 130 °C. The rotary evaporator is Buchi Rotavapor R215, and the vacuum pump is VACUUBRAND GMBH+CO KG MD 1C+AK+EK.

[0149] In this article, the determination of the number average molecular weight (Molecular Weight Average, abbreviated as MWAverage, unit: g / mol) of polyether polyesters requires first carrying out a saponification reaction by adding an excess of KOH, and then acid titrating the remaining alkali to obtain the saponification value SN (Saponification Number, abbreviated as SN, unit: mgKOH / g). The saponification value SN is the equivalent amount of KOH consumed in the saponification reaction of 1 g of the sample. The determination of the saponification value SN is carried out according to the ASTM D94-07(2017) method, and the number average molecular weight is calculated according to the following formula: MWAverage = 56105×2 / SN.

[0150] In this article, the determination of the number average molecular weight (Molecular Weight Average, abbreviated as MWAverage, unit: g / mol) of polyether polyols requires first adding an excess of acetic anhydride to esterify the hydroxyl groups of the sample into ester groups, and then fully hydrolyzing the unreacted acetic anhydride and performing an alkali titration to obtain the hydroxyl value (Hydroxyl number, abbreviated as HN, unit: mgKOH / g). The determination of the hydroxyl value HN is carried out according to the ASTM D4274-05(2010) method. The number average molecular weight is calculated according to the following formula: MWAverage = 56105×2 / HN.

[0151] In this article, the titrator uses the automatic potentiometer T7 of METTLER TOLEDO.

[0152] The molecular weight distribution index is measured by an Agilent 1260 Infinity II gel permeation chromatograph (GPC), and the mobile phase is THF.

[0153] The measurement method of viscosity (Visco) adopts the Ubbelohde viscometer method, and the viscosity is obtained by measuring the time required for a certain volume of liquid to flow through a capillary with a certain length and radius. The viscometer tube is clamped in a constant temperature water bath at 50±0.01 °C. After 20 min, the sample to be measured is sucked from port A to 2-3 mm above the scale line C. When the liquid to be measured flows through the scale line C, record the time t (s) required for the liquid to flow from the scale line C to the scale line E.

[0154] Visco(50 °C) = time s × K (viscometer tube constant) × specific gravity.

Claims

1. A reaction system for preparing a cyclic ether polymer, characterized in that: The reaction system comprises a tube-in-tube fixed bed reactor and a temperature control system; The tube-in-tube fixed bed reactor is provided with a plurality of reaction tubes, and the reaction tubes are provided with internal parts for enhancing material mass transfer and heat transfer. The tube-in-tube fixed bed reactor is divided into two or more independent areas by a partition plate arranged perpendicular to the axial direction of the reaction tubes; the tube-in-tube fixed bed reactor comprises a shell, a cooling medium inlet and a cooling medium outlet arranged on the shell, and a cooling medium inlet and a cooling medium outlet are arranged on the shell of each area; The temperature control system includes a thermometer arranged in part or all of the reaction tubes for measuring the temperature at different axial positions of the reaction tubes, and a cooling medium flowing inside the shell-and-tube fixed bed reactor and in the outer area of ​​the reaction tubes. The temperature control system controls the reaction temperature inside the reaction tubes in the region by independently adjusting the flow rate of the cooling medium in a specific region.

2. The reaction system for preparing a cyclic ether polymer according to claim 1, characterized in that: The reaction system also includes a polymerization product outlet arranged at the bottom of the shell of the shell of the tube-type fixed bed reactor, and a pipeline connecting the shell of the tube-type fixed bed reactor and the polymerization product outlet; the reaction system also includes a feeder arranged on one side of the feed inlet of the shell of the tube-type fixed bed reactor.

3. The reaction system for preparing a cyclic ether polymer according to claim 2, characterized in that: The reaction system also includes a reaction raw material inlet connected to the feeder, and a pipeline connecting the reaction raw material inlet and the feeder; the cooling medium inlet of each zone is arranged at one end of the shell of the shell and tube fixed bed reactor away from the feeder, and the cooling medium outlet of each zone is arranged at one end of the shell of the shell and tube fixed bed reactor close to the feeder.

4. The reaction system for preparing a cyclic ether polymer according to claim 1, characterized in that: The temperature control system comprises a cooling medium cooler, a cooling medium circulation pump, a cooling medium high-level tank and a cooling medium circulation pipeline.

5. The reaction system for preparing a cyclic ether polymer according to claim 4, characterized in that: The pipeline for the circulation of the cooling medium includes a pipeline connecting the cooling medium high-level tank and the cooling medium circulation pump, a pipeline connecting the cooling medium circulation pump and the cooling medium cooler, and a pipeline connecting the cooling medium cooler and the cooling medium inlet; the cooling medium outlet is connected to the pipeline connecting the cooling medium high-level tank and the cooling medium circulation pump through a first pipeline; the pipeline connecting the cooling medium circulation pump and the cooling medium cooler is connected to the pipeline connecting the cooling medium cooler and the cooling medium inlet through a second pipeline; The pipeline connecting the cooling medium cooler and the cooling medium inlet is provided with a valve and a first controller for controlling the opening and closing of the valve, and the first controller is connected to the thermometer through an electronic signal; The second pipeline is provided with a valve and a second controller for controlling the opening and closing of the valve, and the second controller is connected to the thermometer via an electronic signal.

6. The reaction system for preparing a cyclic ether polymer according to claim 1, characterized in that: The shell of the tubular fixed bed reactor is a cylindrical barrel, and the inner diameter of the shell is 200-10000 mm; The inner diameter of the reaction tube is ≥50 mm; The ratio of the inner diameter of the shell to the inner diameter of the reaction tube is (5-100):1; The tube spacing of the reaction tubes is 1-2 times the inner diameter of the reaction tubes; The number of the regions is 2-10.

7. The reaction system for preparing a cyclic ether polymer according to claim 1, characterized in that: The inner part is a tie-type inner part; One or more internal parts are arranged in the reaction tube; The width of the inner part is 40-300 mm; The ratio of the width of the inner part to the inner diameter of the reaction tube is 1:(1-100); The inner part is provided with through holes with a diameter of 1-5 mm and an opening rate of 5%-50%.

8. The reaction system for preparing a cyclic ether polymer according to claim 7, characterized in that: The tie length of the tie-type inner part is 600-1500 mm.

9. The reaction system for preparing a cyclic ether polymer according to claim 7, characterized in that: The ratio of the bond width to the bond length of the bond-type inner part is 1:(5-20).

10. The reaction system for preparing a cyclic ether polymer according to claim 1, characterized in that: All reaction tubes are distributed at equal intervals inside the tube-in-tube fixed bed reactor; Reaction tubes provided with thermometers are evenly distributed inside the tube-in-tube fixed bed reactor; The thermometer is a multi-point thermometer with 2-10 temperature measuring points distributed along the axial direction of the reaction tube.

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