A devolatilization reaction device suitable for high viscosity polymerization production

Abstract

The utility model discloses a kind of devolatilization reaction devices suitable for high viscosity polymerization production, it is related to high molecular polymerization reaction device technical field.The utility model includes inner cylinder, and inner cylinder top end is equipped with stirring part two, and stirring part two bottom is equipped with membrane scraping stirring part, and stirring part two top end is equipped with stirring part one, and stirring part one bottom is equipped with reaction stirring part, and the axis of stirring shaft of stirring part one and stirring part two is collinear;Inner cylinder outside is provided with heat exchange jacket part;Inner cylinder side is provided with outer circulation devolatilization module, and outer circulation devolatilization module is used for circulating devolatilization.The utility model is in by installing coaxial reaction stirring part and membrane scraping stirring part in inner cylinder, and outer circulation devolatilization module is arranged on the outside of inner cylinder, so that the device can realize devolatilization treatment to internal residues while completing reaction, and the production efficiency of polymer is improved.

Description

Technical Field

[0001] This utility model belongs to the technical field of polymer polymerization reaction equipment, specifically relating to a devolatilization reaction device suitable for high viscosity polymerization production. Background Technology

[0002] Polyesters are typically obtained by esterification and polycondensation of dibasic acids and diols. In recent years, polyester products have been developing towards higher molecular weight, higher viscosity, and differentiation. The traditional production of high molecular weight, high viscosity polyesters such as PET, PBT, and PTT requires operating temperatures above 200°C to ensure that the end groups have a certain degree of reactivity. This is achieved by using solid-phase thickening methods to increase the viscosity of the product. However, some polyesters require very high viscosity. In existing technologies, due to the introduction of a third monomer, the melting point of the product is relatively low, making it difficult to increase the viscosity using solid-phase thickening processes. Therefore, melt polycondensation processes are needed to achieve the final viscosity requirements.

[0003] Patent specification CN217042567U discloses a thickening reaction device for the polymerization of polybutylene adipate terephthalate (PAT), including a cylinder with a heat exchange device sleeved on the outside of the cylinder, a gas outlet at the top of the cylinder, and a stirring device installed inside the cylinder. This device achieves efficient devolatilization by setting up a sheet scraper and a spiral scraper. Patent specification CN103319705A discloses a melt polycondensation reaction method, in which molten monomer blends or prepolymers slide down the outer wall of a U-shaped tube to carry out a polycondensation reaction. A heat transfer medium circulates inside the U-shaped tube, and the melt on each U-shaped tube converges to the bottom of the polycondensation reactor for further stirring and mixing. After the reaction is completed, the material is discharged. That is, this device reduces melt adhesion and achieves efficient devolatilization by designing a falling film tube. The shortcomings of the above technical solutions are as follows: First, whether it is scraped film devolatilization or falling film devolatilization, they are essentially evaporation equipment and can only be used as devolatilization equipment, without the function of taking into account the main reaction; Second, the structure of this type of equipment is a vertical, slender cylindrical structure. After the devolatilization is completed, the slender structure makes it difficult to handle the residual polymer material inside, resulting in low efficiency when producing batches of products. Utility Model Content

[0004] The purpose of this invention is to provide a devolatilization reaction device suitable for high viscosity polymerization production. The technical problem to be solved is as follows: the existing devolatilization device can only perform devolatilization treatment and is not conducive to cleaning up the polymer residue inside.

[0005] The objective of this utility model can be achieved through the following technical solutions: A devolatilization reaction device suitable for high-viscosity polymerization production includes an inner cylinder. A second agitator is installed at the top of the inner cylinder, a scraper agitator is installed at the bottom of the second agitator, a first agitator is installed at the top of the second agitator, and a reaction agitator is installed at the bottom of the first agitator. The agitator shafts of the first agitator and the second agitator are collinear. A heat exchange jacket is provided on the outside of the inner cylinder. An external circulation devolatilization module is provided on one side of the inner cylinder for circulating devolatilization.

[0006] As a further embodiment of this utility model: both the first and second stirring components are equipped with stirring motors at their top ends. The output end of the stirring motor of the first stirring component is equipped with a reaction shaft, and the output end of the stirring motor of the second stirring component is equipped with a devolatilization shaft. The devolatilization shaft is hollow, and the top of the reaction shaft extends from the center of the devolatilization shaft to the bottom of the inner cylinder.

[0007] As a further embodiment of this utility model: the heat exchanger jacket kit includes an upper end cap jacket installed on the outer side of the top of the inner cylinder, a devolatilization section jacket installed on the top circumferential side of the inner cylinder, a reaction section side jacket installed on the bottom circumferential side, and a reaction section bottom jacket installed on the bottom of the inner cylinder.

[0008] As a further embodiment of this utility model: a vacuum connection port and a material inlet are installed on one side of the top of the inner cylinder.

[0009] As a further embodiment of this utility model: the bottom end of the reaction shaft is connected to the reaction stirring component, the reaction stirring component includes two vertical frame paddles fixedly connected to the bottom peripheral side of the reaction shaft, and two inclined anchor paddles are fixedly connected to the bottom end of the reaction shaft.

[0010] As a further embodiment of this utility model: a bottom end cap is provided at the bottom of the inner cylinder, a bottom valve is installed at the center of the bottom of the bottom end cap, a jacketed pipe is installed on one side of the bottom of the inner cylinder, a melt transfer pump is installed on one side of the jacketed pipe, and a three-way valve is installed in the middle, an inert gas purging port is installed at the top of the jacketed pipe, and the top end extends into the interior of the inner cylinder, a return inlet is provided on the inner side of the top of the inner cylinder, and the top end of the jacketed pipe is connected to the return inlet.

[0011] As a further embodiment of this utility model: the bottom of the devolatilization shaft is connected to the scraper agitator, and multiple support rods are uniformly installed on the circumferential side of the devolatilization shaft along the scattering direction, with scrapers fixedly connected to the outer side of the support rods.

[0012] The beneficial effects of this utility model are: By installing agitator 1 and agitator 2 at the top of the inner cylinder, and a reaction agitator and a scraping agitator at the bottom of agitator 1 and agitator 2 respectively, and setting the devolatilization shaft of the scraping agitator to be hollow, it is easy for the reaction shaft to pass coaxially through the reaction agitator set at the bottom of the inner cylinder. An external circulation devolatilization module is connected to the outside of the equipment. In use, agitator 1 is turned on first to drive the reaction agitator to stir according to the initial viscosity of the polymer. At this time, no devolatilization reaction is required. As the viscosity of the polymer increases, the external circulation devolatilization module is activated to form an internal and external circulation of the reactants. At this time, agitator 2 is turned on to drive the scraping agitator to perform scraping treatment, and the inner cylinder is evacuated to a vacuum state. The reaction residue in the inner wall of the inner cylinder, which is scraped into a thin film, is boiled off and circulated into the reaction process until the viscosity reaches the predetermined requirement. Then, the material is discharged through a three-way valve and the residue is purged through an inert gas purging port. Thus, the device has the function of completing the devolatilization treatment of the residue inside the equipment while producing polymer. That is, the device can integrate polymer production and residue devolatilization. Furthermore, the strippings formed during the devolatilization reaction in the thickening reaction process re-enter the reaction process, thereby improving the effective utilization rate of the reaction raw materials. In addition, after the reaction is completed, the entire device is in a clean state, which can effectively avoid cross-contamination of residues during the production of recycled batches of polymers, thereby improving the efficiency of recycled production and the quality of finished products. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a partial structural diagram of the top of the inner cylinder of this utility model; Figure 3 This is a top view of the scraper agitator of this utility model; Figure 4 This is a partial structural diagram of the bottom of the inner cylinder of this utility model; Figure 5 This is a top view of the reaction stirring element of this utility model.

[0015] In the diagram: 1. Agitator 1; 2. Agitator 2; 3. Vacuum connection port; 4. Material inlet; 5. Upper head jacket; 6. Deviation section jacket; 7. Scraper agitator; 8. Inner cylinder; 9. Reaction section side jacket; 10. Reaction agitator; 11. Reaction section bottom jacket; 12. Bottom head; 13. Bottom valve; 14. Melt transfer pump; 15. Three-way valve; 16. Jacketed pipe; 17. Return inner inlet; 18. Inert gas purging port; 19. Deviation shaft; 20. Support rod; 21. Scraper; 22. Reaction shaft; 23. Vertical frame paddle; 24. Inclined anchor paddle. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0017] like Figures 1 to 5 As shown, a devolatilization reaction device suitable for high-viscosity polymerization production includes an inner cylinder 8. A second agitator 2 is installed at the top of the inner cylinder 8, a scraper agitator 7 is installed at the bottom of the second agitator 2, a first agitator 1 is installed at the top of the second agitator 2, and a reaction agitator 10 is installed at the bottom of the first agitator 1. The agitator shafts of the first agitator 1 and the second agitator 2 are collinear. A heat exchange jacket is provided on the outside of the inner cylinder 8. An external circulation devolatilization module is provided on one side of the inner cylinder 8 for circulating devolatilization. It should be noted that both agitator 1 and agitator 2 include a stirring motor and a stirring shaft. The stirring shaft of agitator 1 is a solid shaft, namely the reaction shaft 22, while the stirring shaft of agitator 2 is a hollow shaft, namely the devolatilization shaft 19. The two shafts are connected by a sleeve to achieve coaxial use, providing a structural basis for the reaction device to have the dual functions of reaction production and devolatilization thickening. The heat exchange jacket assembly includes an upper end cap jacket 5 installed on the outer side of the top of the inner cylinder 8, a devolatilization section jacket 6 installed on the top circumferential side of the inner cylinder 8, and a reaction section side jacket 9 installed on the bottom circumferential side. The bottom of the inner cylinder 8 is equipped with... The reaction section bottom jacket 11 is heated independently and used to control the temperature of the material at the appropriate height level during the reaction and devolatilization processes. A vacuum connection port 3 is installed on one side of the top of the inner cylinder 8, and a material inlet 4 is installed next to the vacuum connection port 3. The vacuum connection port 3 is used to evacuate the inside of the inner cylinder 8 to a vacuum. At this time, a small amount of unreacted monomers, reaction solvents, and low molecular weight polymers inside the cylinder will experience a sudden drop in boiling point due to the decrease in air pressure. These impurities will instantly boil and vaporize, and can then be peeled off from the inner wall of the equipment. This process is called the removal of volatiles, or devolatilization treatment.

[0018] like Figure 1 , Figure 4 and Figure 5As shown, a reaction shaft 22 is installed at the output end of the agitator 1. The reaction shaft 22 passes through the inner cylinder 8 and is connected to the reaction agitator 10. The reaction agitator 10 includes a vertical frame paddle 23 fixedly connected to the bottom of the shaft, and two inclined anchor paddles 24 are fixedly connected vertically to the vertical frame paddle 23. That is, during the material reaction stage, the agitator 1 is connected to the reaction shaft 22 located at the bottom of the inner cylinder 8. The rotation drives the vertical frame paddle 23 to perform horizontal material shearing, while the inclined anchor paddles 24 flip the material upward when shearing it obliquely. The material that is flipped upward will fall back due to its own weight, thereby enhancing the stirring effect on the reaction material and improving the reaction quality.

[0019] like Figure 1 , Figure 2 and Figure 3 As shown, a bottom end cap 12 is provided at the bottom of the inner cylinder 8. A bottom valve 13 is installed at the center of the bottom of the bottom end cap 12, and a jacketed pipe 16 is installed on one side of the bottom. A melt transfer pump 14 is installed on the side of the jacketed pipe 16 near the inner cylinder 8, and a three-way valve 15 is installed in the middle. An inert gas purging port 18 is installed at the top of the jacketed pipe 16, and the end of the top extends into the interior of the inner cylinder 8. A return inner inlet 17 is provided on the inner side of the top of the inner cylinder 8 to adapt to the jacketed pipe 16, and the end of the jacketed pipe 16 is connected to the return inner inlet 17. The devolatilization shaft 19 installed at the output end of the agitator 2 passes through the inner cylinder 8 and is connected to the scraper agitator 7. The devolatilization shaft 19 is hollow, and six support rods 20 are evenly installed on the circumferential side of the devolatilization shaft 19 along the scattering direction. The scraper 21 is fixedly connected to the outside of the support rods 20.

[0020] The working principle of this utility model: Qualified low-viscosity oligomers (viscosity less than 1 Pa·s) enter the inner cylinder 8 of the polymerization reactor through material inlet 4. At this time, stirrer 1 is turned on and the frequency is adjusted to the working frequency by frequency converter control, preferably 40-50 Hz. Simultaneously, the vacuum system is turned on to perform vacuuming operation through vacuum connection port 3. The reactor temperature is controlled to 210-230℃ by heat exchange jacket kit. This stage is the coarse devolatilization stage. The viscosity of the reactants is low, and the overall reaction is endothermic. The system can ensure that the reactants are in the devolve stage simply by turning on stirrer 1 to drive the reaction stirrer 10 to carry out the conventional reaction. In the volatilization state, both the agitator 2 and the external circulation volatilization module are in the off state. Specifically, the vertical frame paddle 23 at the top of the reaction agitator 10 is an upright frame paddle, and the inclined anchor paddle 24 at the bottom is an inclined anchor paddle. The ratio of the blade diameter of the vertical frame paddle 23 to the bottom inner diameter of the inner cylinder 8 is 0.7-0.95, and the ratio of the blade diameter of the inclined anchor paddle 24 to the bottom inner diameter of the inner cylinder 8 is 0.95-0.99, with an inclination angle of 15°-45°. Through the combined shearing action of the vertical frame paddle 23 and the inclined anchor paddle 24, a rapid and thorough mixing process of low-viscosity materials is achieved, thereby achieving the effect of volatilization and viscosity enhancement.

[0021] As the reaction continues, the viscosity of the polymer gradually increases. When the polymer viscosity exceeds 100 Pa·s, the external circulation devolatilization system is started, and the polymerization system becomes an exothermic reaction. At this time, the temperature of the reaction system is controlled at 250-260℃ by means of heat exchange jacket kit. The flow direction of the three-way valve 15 is adjusted to the direction of the external circulation pipeline. Then the bottom valve 13 is opened. Preferably, the bottom valve 13 is provided with a heat insulation jacket on the outside. The medium in the jacket is high-temperature heat transfer oil. After it is fully opened, the melt transfer pump 14 is started to fill the pipeline with the high-viscosity melt generated by the reactants. It then returns to the inner cylinder 8 along the jacket pipeline 16 and the return inner inlet 17 in sequence, thus forming an internal and external circulation of the reactants. After the circulating material flows normally and the pressure of the melt transfer pump 14 is stable, the scraping film agitator 7 is started to scrape the residue on the inner wall of the inner cylinder 8.

[0022] When the scraper operates stably and the stirring current is stable, the external circulation devolatilization system process is established. Then, the inner cylinder 8 is evacuated from a low vacuum state to a high vacuum state through the vacuum connection port 3, reaching a vacuum level of 100-300 PaA. The melt transfer pump 14 is gradually increased to the working frequency, and then the output motor frequency of the scraper agitator 7 is gradually increased to the working frequency until the external circulation devolatilization module reaches a stable operating state.

[0023] As the devolatilization reaction continues, the viscosity of the polymer increases rapidly. As the viscosity of the system increases, the stirring current of the stirring element 1 increases rapidly. At this stage, the driving force for the viscosity increase is mainly dominated by the devolatilization process. The stirring frequency of the stirring element 10 needs to be gradually reduced according to the rated current of the motor.

[0024] After the external circulation devolatilization module is started and devolatilization continues under high vacuum for about 3 to 4 hours, the polymer viscosity reaches more than 1000 Pa·s, and the polymerization devolatilization system reaches the reaction endpoint. At this time, the device switches to discharge operation. Specifically, the frequency of the melt transfer pump 14 is reduced first, and the flow direction of the melt three-way valve 15 is adjusted to the discharge direction. Then the scraper agitator 7 is turned off, and then the frequency of the melt transfer pump 14 is gradually increased to the working frequency. After the discharge process is completely finished, the melt transfer pump 14 is turned off and the inert gas purging port 18 is opened to discharge the residual material, thereby achieving the cleaning function and avoiding contamination between batches of materials. Preferably, the inert gas interface is installed at the highest point of the jacketed pipe 16.

[0025] At this point, the single batch of polymer production by this device is complete. After the reaction is finished, the polymer viscosity reaches more than 1000 Pa·s, and the system is cleaned. This effectively avoids cross-contamination between batches when the device is used in a cycle, meeting the high-efficiency production requirements of cyclic polymer production.

[0026] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A devolatilization reaction device suitable for high viscosity polymer production, comprising an inner cylinder (8), characterized in that, The inner cylinder (8) is equipped with a second stirring element (2) at the top, a scraper stirring element (7) is installed at the bottom of the second stirring element (2), a first stirring element (1) is installed at the top of the second stirring element (2), and a reaction stirring element (10) is installed at the bottom of the first stirring element (1). The stirring shafts of the first stirring element (1) and the second stirring element (2) are collinear. A heat exchange jacket kit is provided on the outside of the inner cylinder (8). An external circulation devolatilization module is provided on one side of the inner cylinder (8). The external circulation devolatilization module is used for circulation devolatilization.

2. The devolatilization reaction apparatus for high-viscosity polymerization production according to claim 1, characterized in that, Both the first stirring component (1) and the second stirring component (2) are equipped with stirring motors at their top ends. The output end of the stirring motor of the first stirring component (1) is equipped with a reaction shaft (22), and the output end of the stirring motor of the second stirring component (2) is equipped with a devolatilization shaft (19). The devolatilization shaft (19) is hollow, and the top of the reaction shaft (22) extends from the center of the devolatilization shaft (19) to the bottom of the inner cylinder (8).

3. The apparatus for removing the by-products according to claim 1, wherein, The heat exchanger jacket kit includes an upper end cap jacket (5) installed on the outer side of the top of the inner cylinder (8), a devolatilization section jacket (6) installed on the top circumferential side of the inner cylinder (8), a reaction section side jacket (9) installed on the bottom circumferential side, and a reaction section bottom jacket (11) installed on the bottom of the inner cylinder (8).

4. The devolatilization reaction apparatus for high-viscosity polymerization production according to claim 1, characterized in that, The inner cylinder (8) has a vacuum connection port (3) and a material inlet (4) installed on one side of its top end.

5. The apparatus for removing the by-products according to claim 2, wherein The bottom end of the reaction shaft (22) is connected to the reaction stirring component (10). The reaction stirring component (10) includes two vertical frame paddles (23) fixedly connected to the bottom periphery of the reaction shaft (22). The bottom end of the reaction shaft (22) is fixedly connected to two inclined anchor paddles (24).

6. The apparatus for removing the by-products according to claim 1, wherein, The bottom of the inner cylinder (8) is provided with a bottom end cap (12), and a bottom valve (13) is installed at the center of the bottom of the bottom end cap (12). A jacketed pipe (16) is installed on one side of the bottom of the inner cylinder (8). A melt transfer pump (14) is installed on one side of the jacketed pipe (16), and a three-way valve (15) is installed in the middle. An inert gas purging port (18) is installed at the top of the jacketed pipe (16), and the end of the top end extends into the interior of the inner cylinder (8). A return inner inlet (17) is provided on the inner side of the top of the inner cylinder (8), and the top end of the jacketed pipe (16) is connected to the return inner inlet (17).

7. A devolatilization reaction apparatus suitable for high-viscosity polymerization production according to claim 2, characterized in that, The bottom of the devolatilization shaft (19) is connected to the scraper agitator (7). Multiple support rods (20) are evenly installed on the periphery of the devolatilization shaft (19) along the scattering direction. A scraper (21) is fixedly connected to the outside of the support rod (20).

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