Meta-position aramid fiber continuous polymerization device and innovative structures of first reactor and second reactor

Abstract

According to the meta-aramid continuous polymerization process and the innovative structure of the first reactor and the second reactor, the technological process of a newly-designed meta-aramid continuous polymerization device is introduced, a fixed tube plate type heat exchanger and the first reactor are combined into an efficient axial flow type polymerization reactor, and a static mixer is directly inserted into the lower part of a stirrer; reactants are quickly scattered and uniformly distributed when entering the reactor, the temperature of the reactor is effectively controlled, reaction heat is removed, and the flowing state in the reaction kettle is changed. A guide cylinder is additionally arranged at the lower part of a tube bundle, and an asymmetric and helical-surface paddle push-type stirrer is selected to push materials to circularly flow upwards in an inner tube nest and downwards in an outer tube nest, so that vertical circulation is formed. The second reaction kettle adopts a stirrer without a through shaft in the center, inner and outer double helical ribbons and a scraper, so that a flowing dead zone is eliminated, and the mixing of high-viscosity materials is solved. The added three-way ball valve and return line are used for cooling during starting and cleaning of the two reactors during stopping.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer polymerization technology and equipment, and relates to an innovative structure of a meta-aramid continuous polymerization device and a first reactor and a second reactor. Background Art

[0002] The process flow chart of the meta-aramid double reactor polymerization reactor for the "Device for Continuously Preparing High-Purity Meta-aramid Resin Solution" published in the domestic utility model patent is as follows: Figure 1 .

[0003] The output port of the solvent storage tank (1) is connected to the input port of the solvent delivery pump (3), the output port of the solvent delivery pump (3) is connected to the input port of the solvent mass flowmeter (5), and the output port of the solvent mass flowmeter (5) is connected to an input port of a static mixer (7); the output port of the metaphenylenediamine storage tank (2) is connected to the input port of the metaphenylenediamine delivery pump (4), the output port of the metaphenylenediamine delivery pump (4) is connected to the input port of the metaphenylenediamine mass flowmeter (6), and the output port of the metaphenylenediamine mass flowmeter (6) is connected to another input port of the static mixer (7); the output port of the static mixer (7) is connected to the input port of the heat exchanger (8), and the output port of the heat exchanger (8) is connected to an input port of a mixing head (12); the output port of the isophthaloyl chloride storage tank (9) is connected to the input port of the isophthaloyl chloride delivery pump (10), and the output port of the isophthaloyl chloride delivery pump (10) is connected to the input port of the isophthaloyl chloride delivery pump (10). The outlet is connected to the input port of the isophthaloyl chloride mass flowmeter (11), and the output port of the isophthaloyl chloride mass flowmeter (11) is connected to another input port of the mixing head (12); the output port of the mixing head (12) is connected to the input port of the first polymerization reactor (13), the output port of the first polymerization reactor (13) is connected to the input port of the resin solution delivery pump (14), the output port of the resin solution delivery pump (14) is connected to the input port of the second polymerization reactor (15), and the output port of the second polymerization reactor (15) is connected to the input port of the resin solution storage tank (16); the input port of the first polymerization reactor (13) is arranged at the bottom end of the reactor, and the output port is arranged at the side portion which is roughly at the same horizontal line position as the upper end of the stirring blade; the input port of the second polymerization reactor (15) is arranged at the bottom end of the reactor, and the output port is arranged at the side portion which is roughly at the same horizontal line position as the upper end of the stirring blade.

[0004] The agitator of the first polymerization reactor (13) is a combined agitator, wherein the lower part of the agitator adopts at least two layers of four-blade 45° inclined paddle agitators, and the height of the inclined paddle agitators is 1 to 5 times the inner diameter of the reactor; the middle part of the agitator adopts double-screw type agitators, and the height of the double-screw type agitators is 10 to 15 times the inner diameter of the reactor; the upper part of the agitator adopts frame type agitators, and the height of the frame type agitators is 1 to 4 times the inner diameter of the reactor.

[0005] A heat exchange jacket or heat exchange coil is arranged on the periphery of the second polymerization reactor (15). The agitator of the second polymerization reactor (15) is a combined agitator, wherein the lower part of the agitator adopts an anchor-type agitator blade, and the height of the anchor-type agitator blade is 0.5 to 1.5 times of the inner diameter of the reactor; the upper part of the agitator adopts a double-screw type agitator blade, and the height of the double-screw type agitator blade is 10 to 20 times of the inner diameter of the reactor; a single-screw type agitator blade is arranged inside the double-screw type agitator blade, and the height of the single-screw type agitator blade is the same as that of the double-screw type agitator blade. Summary of the invention

[0006] The changes compared with the original flow chart are as follows: in the process flow, the original heat exchanger (8) and the first polymerization reactor (13) are integrated into one, the original mixing head (12) is changed to a three-way ball valve (12), the installation position of the static mixer (7) is changed to the bottom of the kettle of the first polymerization reactor (13), and the outlet is directly inserted into the lower part of the stirrer in the kettle, so that the material is quickly broken up by the stirrer blades after entering, so that it is evenly distributed, the isophthaloyl chloride storage tank (9) is connected to the isophthaloyl chloride delivery pump (10) and the isophthaloyl chloride mass flowmeter (11) from the side of the static mixer (7) shell, and a reflux line (17) is added.

[0007] The output port of the solvent storage tank (1) is connected to the input port of the solvent delivery pump (3), the output port of the solvent delivery pump (3) is connected to the input port of the solvent mass flow meter (5), and the output port of the solvent mass flow meter (5) is connected to the inlet of the static mixer (7); the output port of the metaphenylenediamine storage tank (2) is connected to the input port of the metaphenylenediamine delivery pump (4), the output port of the metaphenylenediamine delivery pump (4) is connected to the input port of the metaphenylenediamine mass flow meter (6), and the output port of the metaphenylenediamine mass flow meter (6) is connected to the inlet of the static mixer (7). The output port of the isophthaloyl chloride storage tank (9) is connected to the isophthaloyl chloride delivery pump (10) and the isophthaloyl chloride mass flowmeter (11), and is input into the first polymerization reactor (13) from the shell of the static mixer (7). The output port of the upper part of the first polymerization reactor (13) is connected to the input port of the resin solution delivery pump (14), and the output port of the resin solution delivery pump (14) enters the bottom inlet of the second polymerization reactor (15), and the upper outlet of the second polymerization reactor (15) is connected to the input port of the resin solution storage tank (16). The first innovation point is that the heat exchanger and the first polymerization reactor (13) are combined into one device, and a high-efficiency axial flow propulsion agitator is adopted. The static mixer (7) is directly inserted into the existing head of the reactor. The second innovation point is that the second polymerization reactor (15) adopts a stirrer with a central non-through shaft + inner and outer double spiral belts + scrapers.

[0008] When starting the system, the flow direction of the three-way ball valve (8) and the three-way ball valve (12) in the process is changed, and the solvent in the solvent storage tank (1) is first returned to the solvent storage tank (1) through the reflux line (17) using the refrigerant between the pipes of the first polymerization reactor (13) and the refrigerant in the jacket of the second polymerization reactor (15) to reduce the temperature in the system; when stopping the system, this line is used to clean the glue hanging in the two polymerization reactors.

[0009] The innovative first polymerization reactor (13) is based on the structure of the axial flow patent for butyl rubber polymerization reactor used by Exxon Corporation in the United States in 1995. The main structural concept is based on the article "Structural Design of High-efficiency Axial Flow Polymerization Reactor" published by Meng Ming in the third issue of "Petrochemical Technology" in 2021. The design pressure of the first polymerization reactor (13) is 0.6MPa, the design temperature is 10°C, and the viscosity range is less than 2.0Pa.s. This requires that the feed temperature be lowered before entering the first polymerization reactor (13). The first polymerization reactor (13) adopts a shell-and-tube heat exchanger structure and an agitator to form a new first polymerization reactor (13). Its structure is shown in Figure 3 .

[0010] The tube bundle barrel (13-2) of the innovative first polymerization reactor (13) adopts a fixed tube sheet heat exchanger structure, and a guide tube (13-3) is added to the upper concave structure in the middle of the bottom, and the tube bundle is divided into two areas: an inner tube array (13-9) and an outer tube array (13-8). The inner tube array (13-9) area in the guide tube is acted upon by the thrust of the agitator, and the liquid flows upward from the inner tube array (13-9); then it flows downward from the outer tube array (13-8) area, forming a vertical annular flow in the kettle to exchange heat and extend the residence time; a refrigerant is passed through the outside of the tubes to extract the reaction heat. The diameter and number of the outer tube array (13-8) and the inner tube array (13-9) are selected according to the viscosity. A large tube diameter is selected for high viscosity and a small heat exchange area, and a small tube diameter is selected for low viscosity and a large heat exchange area. The flow areas of the outer tube array (13-8) and the inner tube array (13-9) are basically the same, and the tube arrangement is as follows: Figure 3 As shown in AA.

[0011] The agitator of the innovative first polymerization reactor (13) adopts a layer of 9 to 15 asymmetric propulsion blades to increase the axial thrust of the liquid. The hub diameter is determined according to the flow rate. The upper end of the agitator adopts a water drop-shaped guide cover to reduce flow resistance and accelerate the flow of materials. The blade configuration is as follows: Figure 3 As shown in the BB cross-sectional view.

[0012] The innovative first polymerization reactor (13) has six static guide vanes (13-4) added to the guide tube, which are fixed in the middle guide tube to change the rotating liquid flow into a linear flow, thereby promoting uniform distribution of the reaction liquid and flowing along the inner tube array (13-9).

[0013] The main structural concept of the innovative aramid second polymerization reactor (15) refers to the article "No-through-shaft, screw-ribbon agitator in the application center of the first kettle of cis-1,2-dimethyl-1-propene rubber polymerization" published by Meng Ming in the first issue of "Petrochemical Technology" in 2021, and its application results in cis-1,2-dimethyl-1-propene rubber polymerization kettles from 2007 to date, and a new design of the meta-aramid second polymerization reactor (15) is carried out. The differences are as follows: its structure is as follows Figure 4 shown.

[0014] The main structure of the innovative aramid second polymerization reactor (15) is as follows: Figure 4 As shown: the design pressure is 0.6MPa, the design temperature is 20℃, the viscosity range is less than 150Pa.s, and the kettle body adopts a height / diameter ratio of 2 to 4 to increase the heat exchange area; according to the high viscosity of the material in the second polymerization reactor (15), a combined frame shaft without a central through shaft is adopted to improve the anti-torsion force of the shaft, and there is no "pole climbing problem" of the material holding the shaft; multiple layers of inner double spiral belts (15-7) are fixed on the inner combined frame (15-8), and multiple layers of outer double spiral belts (15-6) are fixed on the outer combined frame shaft (15-5) The inner and outer spiral belts have opposite rotation directions. The outer double spiral belt (15-6) lifts the material, and the inner double spiral belt (15-7) presses the material downward, forming a vertical circulation in the reactor. The outer combined frame shaft (15-5) is close to the kettle wall, which is convenient for setting the scraper (15-7). The multiple scrapers (15-7) at different positions on the outer frame can clean the adhesive hanging on the kettle wall, which is beneficial to heat exchange, and can also eliminate the flow dead zone in the reactor, prolong the residence time and heat exchange, and maintain the temperature balance in various places in the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 .Meta-aramid double reactor polymerization process flow chart

[0016] A solvent storage tank (1), an m-phenylenediamine storage tank (2), a solvent delivery pump (3), an m-phenylenediamine delivery pump (4), a solvent mass flow meter (5), an m-phenylenediamine mass flow meter (6), a static mixer (7), a heat exchanger (8), an isophthaloyl chloride storage tank (9), an isophthaloyl chloride delivery pump (10), an isophthaloyl chloride mass flow meter (11), a mixing head (12), a first polymerization reactor (13), a resin solution delivery pump (14), a second polymerization reactor (15), and a resin solution storage tank (16).

[0017] Figure 2 .Innovative flow chart of aramid dual reactor polymerization process

[0018] A solvent storage tank (1), an m-phenylenediamine storage tank (2), a solvent delivery pump (3), an m-phenylenediamine delivery pump (4), a solvent mass flow meter (5), an m-phenylenediamine mass flow meter (6), an insert-type static mixer (7), a three-way ball valve (8), an isophthaloyl chloride storage tank (9), an isophthaloyl chloride delivery pump (10), an isophthaloyl chloride mass flow meter (11), a three-way ball valve (12), a first polymerization reactor (13), a resin solution delivery pump (14), a second polymerization reactor (15), a resin solution storage tank (16), and a reflux line (17).

[0019] Figure 3 .Aramid first polymerization reactor

[0020] Upper head (13-1), tube bundle body (13-2), guide tube (13-3), stationary guide vane (13-4), 15-blade propeller agitator (13-5), lower head (13-6), drive device (13-7), outer tube row (13-8), inner tube row (13-9), AA section view, BB section view, the red arrow in the figure indicates the direction of liquid flow.

[0021] Figure 4 .Aramid Second Polymerization Reactor

[0022] A driving device (15-1), an upper stirring shaft (15-2), an upper head (15-3), a kettle body with a jacket (15-4), an outer combined frame shaft (15-5), an outer double spiral belt (15-6), an inner double spiral belt (15-7), an inner combined frame (15-8), a scraper (15-9) and a lower stirring shaft (15-10). DETAILED DESCRIPTION

[0023] From the process flow, it is necessary to connect the output port of the solvent storage tank (1) to the input port of the solvent delivery pump (3), the output port of the solvent delivery pump (3) to the input port of the solvent mass flow meter (5), and the output port of the solvent mass flow meter (5) to the inlet of the static mixer (7); the output port of the m-phenylenediamine storage tank (2) to the input port of the m-phenylenediamine delivery pump (4), the output port of the m-phenylenediamine delivery pump (4) to the input port of the m-phenylenediamine mass flow meter (6), and the output port of the m-phenylenediamine mass flow meter (6) to the inlet of the static mixer. The output port of the isophthaloyl chloride storage tank (9) is connected to the isophthaloyl chloride delivery pump (10) and the isophthaloyl chloride mass flowmeter (11), and is input into the first polymerization reactor (13) from the shell of the static mixer (7). The output port of the upper part of the first polymerization reactor (13) is connected to the input port of the resin solution delivery pump (14), and the output port of the resin solution delivery pump (14) enters the bottom inlet of the second polymerization reactor (15). The upper outlet of the second polymerization reactor (15) is connected to the input port of the resin solution storage tank (16).

[0024] The flow direction of the three-way ball valve (8) and the three-way ball valve (12) in the process is changed. When starting, the solvent in the solvent storage tank (1) is first returned to the solvent storage tank (1) through the reflux line (17) using the refrigerant between the pipes of the first polymerization reactor (13) and the refrigerant in the jacket of the second polymerization reactor (15) to reduce the temperature in the system; when stopping, this line is used to clean the glue hanging in the two polymerization reactors.

[0025] The innovative first polymerization reactor (13) has a design pressure of 0.6 MPa, a design temperature of 10°C, and a viscosity range of less than 2.0 Pa.s. This requires that the feed temperature be lowered before entering the first polymerization reactor (13). The first polymerization reactor (13) adopts a shell-and-tube heat exchanger structure and is equipped with a stirrer to form a new first polymerization reactor (13). The structure is shown in FIG. Figure 3 . The tube bundle cylinder (13-2) adopts a fixed tube plate heat exchanger structure, and a guide tube (13-3) is added to the upper concave structure in the middle of the bottom, and the tube bundle is divided into two areas: an inner tube (13-9) and an outer tube (13-8). The inner tube (13-9) area in the guide tube is acted upon by the thrust of the agitator, and the liquid flows upward from the inner tube (13-9); then it flows downward from the outer tube (13-8) area, forming a vertical annular flow in the kettle to exchange heat and extend the residence time; a refrigerant is passed through the outside of the tube to extract the reaction heat. The diameter and number of the outer tube (13-8) and the inner tube (13-9) are selected according to the viscosity. A large tube diameter is selected for a high viscosity and a small heat exchange area, and a small tube diameter is selected for a low viscosity and a large heat exchange area. The flow areas of the outer tube (13-8) and the inner tube (13-9) are basically the same, and the tube arrangement is as follows: Figure 3The agitator uses a layer of 9 to 15 asymmetric propulsion blades to increase the axial thrust of the liquid. The hub diameter is determined according to the flow rate. The upper end of the agitator uses a water droplet-shaped guide cover to reduce flow resistance and accelerate the flow of materials. The blade configuration is as follows: Figure 3 As shown in the BB cross-sectional view.

[0026] The main structure of the innovative aramid second polymerization reactor (15) is as follows: Figure 4 As shown: the design pressure is 0.6MPa, the design temperature is 20℃, the viscosity range is less than 150Pa.s, and the kettle body adopts a height / diameter ratio of 2 to 4 to increase the heat exchange area; according to the high viscosity of the material in the second polymerization reactor (15), a combined frame shaft without a central through shaft is adopted to improve the anti-torsion force of the shaft, and there is no "pole climbing problem" of the material holding the shaft; multiple layers of inner double spiral belts (15-7) are fixed on the inner combined frame (15-8), and multiple layers of outer double spiral belts (15-6) are fixed on the outer combined frame shaft (15-5) The inner and outer spiral belts have opposite rotation directions. The outer double spiral belt (15-6) lifts the material, and the inner double spiral belt (15-7) presses the material downward, forming a vertical circulation in the reactor. The outer combined frame shaft (15-5) is close to the kettle wall, which is convenient for setting the scraper (15-7). The multiple scrapers (15-7) at different positions on the outer frame can clean the adhesive hanging on the kettle wall, which is beneficial to heat exchange, and can also eliminate the flow dead zone in the reactor, prolong the residence time and heat exchange, and maintain the temperature balance in various places in the reactor.

[0027] The newly designed process flow of the meta-aramid continuous polymerization device and the innovative structure of the first and second reactors are the first of their kind in China. The main equipment used for aramid polymerization production can not only solve the production process problems of domestic aramid enterprises, improve production capacity and product quality, reduce costs, and enhance the competitiveness of enterprises, but also open up a path for China's independent development. The innovative structure of the first and second reactors is also suitable for the reaction, polycondensation and mixing of other high-viscosity materials.

Claims

1. The innovative structure of the meta-aramid continuous polymerization device and the first and second reactors is characterized by: The output port of the solvent storage tank (1) is connected to the input port of the solvent delivery pump (3), the output port of the solvent delivery pump (3) is connected to the input port of the solvent mass flowmeter (5), and the output port of the solvent mass flowmeter (5) is connected to the inlet of the static mixer (7); the output port of the m-phenylenediamine storage tank (2) is connected to the input port of the m-phenylenediamine delivery pump (4), the output port of the m-phenylenediamine delivery pump (4) is connected to the input port of the m-phenylenediamine mass flowmeter (6), the output port of the m-phenylenediamine mass flowmeter (6) is connected to the inlet of the static mixer (7), the output port of the isophthaloyl chloride storage tank (9) is connected to the isophthaloyl chloride delivery pump (10) and the isophthaloyl chloride mass flowmeter (11), and the The shell of the static mixer (7) is input into the first polymerization reactor (13), the output port on the top of the first polymerization reactor (13) is connected to the input port of the resin solution delivery pump (14), the output port of the resin solution delivery pump (14) enters the bottom inlet of the second polymerization reactor (15), and the upper outlet of the second polymerization reactor (15) is connected to the input port of the resin solution storage tank (16). The first innovation is that the heat exchanger and the first polymerization reactor (13) are combined into one device, and a high-efficiency axial flow propulsion agitator is adopted. The static mixer (7) is directly inserted into the existing head of the reactor. The second innovation is that the second polymerization reactor (15) adopts an agitator with a center-free through-shaft + inner and outer double spiral belts + scrapers.

2. The meta-aramid continuous polymerization device and the first and second reactors according to claim 1, characterized in that: When starting the system, the flow direction of the three-way ball valve (8) and the three-way ball valve (12) in the process is changed, and the solvent in the solvent storage tank (1) is first returned to the solvent storage tank (1) through the reflux line (17) using the refrigerant between the pipes of the first polymerization reactor (13) and the refrigerant in the jacket of the second polymerization reactor (15) to reduce the temperature in the system; when stopping the system, this line is used to clean the glue hanging in the two polymerization reactors.

3. The first reactor of the meta-aramid continuous polymerization device according to claim 1, characterized in that: The design pressure is 0.6MPa, the design temperature is 10℃, and the viscosity range is less than 2Pa.s. The innovative first polymerization reactor (13) tube bundle cylinder (13-2) adopts a fixed tube plate heat exchanger structure, and a guide tube (13-3) is added to the upper concave structure in the middle of the bottom, and the tube bundle is divided into two areas: inner tube array (13-9) and outer tube array (13-8). The inner tube array (13-9) area in the guide tube is affected by the thrust of the agitator, and the liquid flows upward from the inner tube array (13-9); then it flows downward from the outer tube array (13-8) area, forming a vertical annular flow in the kettle, exchanging heat and extending the residence time; a refrigerant is passed through the outside of the tube to discharge the reaction heat.

4. The innovative first polymerization reactor (13) according to claim 3, characterized in that: The diameter and number of the outer tube array (13-8) and the inner tube array (13-9) are selected according to the viscosity. A large tube diameter is selected for high viscosity and a small heat exchange area. A small tube diameter is selected for low viscosity and a large heat exchange area. The flow areas of the outer tube array (13-8) and the inner tube array (13-9) are basically the same. The tube array arrangement is shown as AA in FIG3 .

5. The innovative first polymerization reactor (13) according to claim 3, characterized in that: The agitator adopts a layer of 15 asymmetric propulsion blades to increase the axial thrust of the liquid. The hub diameter is determined according to the flow rate. A teardrop-shaped flow guide cover is adopted at the upper end of the agitator to reduce the flow resistance and accelerate the flow of the material. The blade configuration is shown in the BB cross-sectional view in Figure 3. The agitator adopts a layer of 9_15 asymmetric propulsion blades to increase the axial thrust of the liquid. The hub diameter is determined according to the flow rate. A teardrop-shaped flow guide cover is adopted at the upper end of the agitator to reduce the flow resistance and accelerate the flow of the material. The blade configuration is shown in the BB cross-sectional view in Figure 3. Six static guide static guide blades (13-4) are added in the guide tube, and the rotating liquid flow is changed into a straight flow in the fixed middle guide tube, so as to promote the uniform distribution of the reaction liquid and flow along the inner tube (13-9).

6. The second reactor of the meta-aramid continuous polymerization device according to claim 1, characterized in that: The design pressure is 0.6MPa, the design temperature is 20°C, the viscosity range is less than 150Pa.s, and the kettle body adopts a height / diameter ratio greater than 2 to increase the heat exchange area; according to the characteristic of high viscosity of the material in the second polymerization reactor (15), a combined frame shaft without a through shaft in the center + inner and outer double spiral belt blades + scraper-type agitator are adopted to improve the anti-torsion force of the shaft and eliminate the "pole climbing problem" of the material holding the shaft; multiple layers of inner double spiral belts (15-7) are fixed on the inner combined frame (15-8), and multiple layers of outer double spiral belts (15-6) are fixed on the outer combined frame shaft (15-5). The rotation directions of the inner and outer spiral belts are opposite, the outer double spiral belt (15-6) lifts the material, and the inner double spiral belt (15-7) presses the material downward, forming a vertical circulation in the reactor.

7. The second reactor of the meta-aramid continuous polymerization device according to claim 5 is provided with a scraper on the combined frame shaft, characterized in that: The outer combined frame shaft (15-5) is close to the kettle wall, which is convenient for setting the scraper (15-7). The multiple scrapers (15-7) at different positions on the outer frame can clean the adhesive hanging on the kettle wall, which is beneficial to heat exchange and can also eliminate the flow dead zone in the reactor, prolong the residence time and heat exchange, and maintain the temperature balance at various locations in the reactor.

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