A reaction separation system device for polyester degradation and its application

Abstract

This invention discloses a reaction separation system for polyester degradation, comprising a solvent storage tank, a first transfer pump, a polyester degradation reaction vessel, a magnetic separation tube, a degradation product storage tank, a separation and post-processing tank, a solvent recovery storage tank, a second transfer pump, a catalyst recovery tank, and a third transfer pump. The invention also discloses the application steps of the above-mentioned reaction separation system in the polyester degradation reaction. The magnetic catalyst separation system (magnetic separation tube, catalyst recovery tank, and solvent recovery storage tank) of this invention can conveniently and efficiently separate polyester degradation products from the magnetic catalyst, effectively improving the catalyst reuse rate and reducing the cost of using the polyester catalyst. Simultaneously, this system organically combines polyester degradation, catalyst separation, and product processing, which helps reduce equipment investment and energy consumption, and has important guiding significance for the industrial process of polyester degradation.

Description

Technical Field

[0001] This invention belongs to the field of process equipment and application technology for polyester degradation, and in particular relates to a reaction separation system device and its application for polyester degradation. Background Technology

[0002] Polyester is a general term for polymers obtained by the condensation polymerization of polyols and polyacids. Currently, it mainly refers to polyethylene terephthalate (PET), which has characteristics such as high transparency, chemical resistance, good insulation, low hygroscopicity, stability, and excellent mechanical properties. It is widely used in textiles, plastic bottles, and sheets. Currently, global PET production is growing rapidly, reaching 51.3 million tons in 2010, 64.62 million tons in 2015, and is projected to reach approximately 79.92 million tons in 2020.

[0003] Recycling PET is of great significance as a resource. The main methods for recycling PET include energy recovery, physical methods, and chemical methods. Energy recovery methods release the energy stored in the plastic through incineration and recover the heat. While this avoids the separation of various wastes, incineration produces harmful gases such as dioxins and is not yet widely accepted. Physical methods, also known as mechanical recycling, include processes such as impurity removal, crushing, and melt regeneration. This method has high requirements for waste materials and can easily lead to a decline in product performance, thus representing a downgraded recycling of PET. Chemical methods refer to the process of degrading molecular chains into monomers or oligomers through specific reactions in solvents such as water, alcohols, acids, and amines. This is the only method considered to conform to the principle of "sustainable development" because the monomers or oligomers obtained from chemical degradation can be separated and purified and reused in the synthesis of high-quality chemicals, representing a closed-loop recycling of PET.

[0004] However, in chemical recycling methods, catalysts for PET degradation are often difficult to recover and have high usage costs. For example, AMAl-Sabagh et al. used Fe3O4 supported on carbon nanotubes to degrade PET, which could be completely degraded at 190°C for two hours (AMAl-Sabagh, FZYehia, DRKHarding, et al. Fe3O4-boosted MWCNT as an efficient sustainable catalyst for PET glycolysis[J]. Green Chemistry, 2016, 18:3997-4003.), but this catalyst is prone to agglomeration, affecting its catalytic performance. One solution is to prepare the active material into a pseudo-homogeneous catalyst that can be uniformly dispersed in the reaction system. This can achieve monodispersity of catalyst particles in the reaction system, which is beneficial for sufficient contact with reactants and reduces mass transfer resistance. At the same time, they did not develop a magnetic separation device for the catalyst. Therefore, developing an integrated reaction and separation system with a simple structure that can be used for polyester degradation has important practical application value. Summary of the Invention

[0005] The first technical problem this invention aims to solve is to provide a reaction separation system for polyester degradation. This system primarily addresses the difficulty in recovering and separating conventional catalysts during polyester degradation, achieving the separation and recovery of magnetic catalysts used in polyester degradation in a simple and easy-to-operate manner.

[0006] The second technical problem to be solved by the present invention is to provide the application of the above-mentioned reaction separation system device in polyester degradation.

[0007] To solve the first technical problem mentioned above, the present invention adopts the following technical solution:

[0008] A reaction separation system for polyester degradation includes a solvent storage tank, a first transfer pump, a polyester degradation reaction vessel, a magnetic separation tube, a degradation product storage tank, a separation and post-processing tank, a solvent recovery storage tank, a second transfer pump, a catalyst recovery tank, and a third transfer pump.

[0009] The solvent storage tank outlet is connected to the first delivery pump inlet via a pipeline;

[0010] The outlet of the first delivery pump is connected to the inlet of the polyester degradation reactor via a pipeline;

[0011] The bottom outlet of the polyester degradation reactor is connected to the inlet of the magnetic separation tube via a pipe.

[0012] The outlet of the magnetic separation tube is connected to the inlet of the degradation product storage tank via a pipeline;

[0013] The bottom outlet of the degradation product storage tank is connected to the inlet of the separation and post-processing tank via a pipeline.

[0014] The outlet of the separation and post-processing tank is connected to the inlet of the solvent recovery storage tank via a pipeline;

[0015] The solvent recovery storage tank is connected to the second transfer pump via a pipeline;

[0016] The outlet of the second delivery pump is connected to the pipeline between the magnetic separation pipe and the degradation product storage tank;

[0017] A catalyst recovery tank is connected to the connecting pipe between the polyester degradation reactor and the magnetic separation tube.

[0018] The catalyst recovery tank is connected to the third transfer pump;

[0019] The outlet of the third delivery pump is connected to the polyester degradation reactor via a pipeline.

[0020] Preferably, the polyester degradation reactor is equipped with a stirring device.

[0021] Preferably, the stirring rate of the stirring device is 100-500 r / min; more preferably, the stirring rate is 300-500 r / min.

[0022] Preferably, a discharge valve, which is a ball valve, is provided on the connecting pipe between the polyester degradation reactor and the magnetic separation tube.

[0023] Preferably, a constant temperature system is provided outside the magnetic separation tube.

[0024] Preferably, the magnetic separator is provided with a magnetic structure, which is a permanent magnet or an electromagnet. The magnetic structure is a cylindrical structure with a split center, and the inner diameter of the cylindrical structure is the same as the outer diameter of the magnetic separator. The magnetic field strength on the surface of the magnetic structure is greater than 6000GS.

[0025] Preferably, the magnetic separation tube is a non-magnetic metal tube or a quartz tube.

[0026] Preferably, a feed valve, which is a ball valve, is installed on the pipeline between the magnetic separation tube and the degradation product storage tank.

[0027] Preferably, a cooling device is provided on the outer wall of the degradation product storage tank, which can cool the temperature inside the degradation product storage tank to below 0°C.

[0028] Preferably, the center of gravity of the polyester degradation reactor is higher than that of the degradation product storage tank.

[0029] To address the second technical problem mentioned above, the present invention provides the application of the above-mentioned reaction separation system device in polyester degradation, comprising the following steps:

[0030] S1. Add polyester fragments, alcoholysis agent, and magnetic catalyst to a sealed polyester degradation reactor and react at 170-220℃ for 1-2 hours until the polyester is completely degraded to obtain a reaction solution.

[0031] S2. The reaction liquid enters the magnetic separation tube through the bottom outlet of the polyester degradation reactor and the discharge valve. The magnetic structure outside the magnetic separation tube is used to separate the magnetic catalyst in the reaction liquid to obtain a polyester degradation mixture.

[0032] S3. The polyester degradation mixture is transported to the degradation product storage tank, cooled by the cooling device outside the degradation product storage tank, and then transported to the separation and post-processing device for filtration and washing to obtain the solid filter cake.

[0033] S4. The solid filter cake is dried to obtain the degradation products. The filtrate is distilled to obtain the alcoholysis agent, which is then transported to the solvent recovery storage tank.

[0034] Preferably, in step S1, the polyester is selected from one or more of polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyarylate, and polyurethane.

[0035] Preferably, in step S1, the magnetic catalyst is selected from Fe3O4 nanoparticle dispersion, Co3O4 nanoparticle dispersion, and ferrate (M x Fe 3-x O4 (M = Cu, Zn, Mg, Co, Ni) nanoparticle dispersions, wherein the average particle size is between 1-100 nm; preferably, the average particle size is between 1-30 nm. The dispersion should ideally be a catalyst with small particle size, high dispersibility, good magnetic response, and strong reactivity, which is beneficial for increasing the reaction rate and facilitating magnetic recovery of the catalyst.

[0036] Preferably, in step S1, the mass ratio of polyester: alcoholysis agent: magnetic catalyst is 1:4-15:0.01-0.05. If the proportion of alcoholysis agent is too low, the degradation efficiency of the polyester will decrease, and the viscosity of the mixture will increase, which is not conducive to mass production. If the proportion of alcoholysis agent is too high, it will lead to solvent waste and increase the cost of subsequent alcoholysis agent recovery. If the catalyst content is too low, the catalytic effect on polyester degradation will be insignificant, which is not conducive to the reaction. If the catalyst content is too high, it will also lead to catalyst waste.

[0037] Preferably, in step S2, the temperature inside the magnetic separation tube is 60-80℃. This is to prevent the precipitation of reaction products from affecting the adsorption and separation of the magnetic catalyst.

[0038] Preferably, in step S3, the cooling device cooling refers to cooling the material in the degradation product storage tank to below 0°C.

[0039] Preferably, in step S4, the drying temperature is 80-110°C.

[0040] Preferably, in step S4, the alcoholysis agent obtained after distillation of the filtrate is returned to step S1 for recycling. The recycling of the alcoholysis agent helps reduce the raw material cost of the reaction and achieves green and sustainable utilization of the raw materials. The magnetic recovery system includes a solvent recovery tank, a magnetic separation tube, and a catalyst recovery tank, where the catalyst can be replenished.

[0041] Any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints.

[0042] Unless otherwise specified, all raw materials used in this invention can be obtained commercially, and the equipment used in this invention can be conventional equipment in the relevant field or refer to existing technology in the relevant field.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The magnetic catalyst separation system (magnetic separation tube, catalyst recovery tank, and solvent recovery storage tank) of this invention can conveniently and efficiently separate polyester degradation products from magnetic catalysts, effectively improving catalyst reuse rate and reducing the cost of polyester catalyst use. Simultaneously, this system organically combines polyester degradation, catalyst separation, and product processing, which helps reduce equipment investment and energy consumption, and has significant guiding significance for the industrial process of polyester degradation. Attached Figure Description

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Figure 1 This is a schematic diagram of the reaction separation system device for polyester degradation according to the present invention. Detailed Implementation

[0047] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0048] As one aspect of the present invention, a reaction separation system apparatus for polyester degradation includes:

[0049] Solvent storage tank 1,

[0050] First delivery pump 11,

[0051] Polyester degradation reactor 2,

[0052] Magnetic separation tube 3,

[0053] Degradation product storage tank 4,

[0054] Separation and post-processing tank 5,

[0055] Solvent recovery storage tank 6,

[0056] Second delivery pump 61,

[0057] Catalyst recovery tank 7, and

[0058] Third delivery pump 71.

[0059] The outlet of the solvent storage tank 1 is connected to the inlet of the first transfer pump 11 via a pipeline;

[0060] The outlet of the first delivery pump 11 is connected to the inlet of the polyester degradation reactor 2 via a pipeline;

[0061] The bottom outlet of the polyester degradation reactor 2 is connected to the inlet of the magnetic separation tube 3 via a pipe.

[0062] The outlet of the magnetic separation tube 3 is connected to the inlet of the degradation product storage tank 4 via a pipeline.

[0063] The bottom outlet of the degradation product storage tank 4 is connected to the inlet of the separation and post-processing tank 5 via a pipeline.

[0064] The outlet of the separation and post-processing tank 5 is connected to the inlet of the solvent recovery storage tank 6 via a pipeline.

[0065] The solvent recovery storage tank 6 is connected to the second transfer pump 61 via a pipeline;

[0066] The outlet of the second delivery pump is connected to the pipeline between the magnetic separation pipe and the degradation product storage tank;

[0067] The catalyst recovery tank 7 is connected to the connecting pipe between the polyester degradation reactor 2 and the magnetic separation tube 3.

[0068] The catalyst recovery tank 7 is connected to the third transfer pump 71;

[0069] The outlet of the third delivery pump 71 is connected to the polyester degradation reactor 2 via a pipeline.

[0070] The above-described system of the present invention can flow the polyester degradation mixture (including solvent, degradation products and catalyst) in the polyester degradation reactor 2 through the magnetic separation tube 3. The magnetic catalyst present in the polyester degradation mixture is adsorbed on the inner wall of the magnetic separation tube 3 under the action of the magnetic structure, while the polyester degradation products and solvent flow into the degradation product storage tank 4. This can simply achieve efficient separation of polyester products and magnetic catalyst and improve the utilization rate of catalyst.

[0071] In some embodiments of the present invention, the polyester degradation reactor 2 is equipped with a stirring device.

[0072] In some embodiments of the present invention, the stirring rate of the stirring device is 100-500 r / min; preferably, the stirring rate is 300-500 r / min.

[0073] In some embodiments of the present invention, a discharge valve 23 is provided on the connecting pipe between the polyester degradation reactor 2 and the magnetic separation tube 3, and the discharge valve is a ball valve.

[0074] In some embodiments of the present invention, a constant temperature system 32 is provided outside the magnetic separation tube 3.

[0075] In some embodiments of the present invention, the magnetic separation tube 3 is provided with a magnetic structure 31, which is a permanent magnet or an electromagnet. The magnetic structure is a cylindrical structure with a middle split, and the inner diameter of the cylindrical structure is the same as the outer diameter of the magnetic separation tube. The magnetic field strength on the surface of the magnetic structure is greater than 6000GS.

[0076] In some embodiments of the present invention, the magnetic separation tube 3 is a non-magnetic metal tube or a quartz tube.

[0077] In some embodiments of the present invention, a feed valve 33 is provided on the pipeline between the magnetic separation tube 3 and the degradation product storage tank 4, and the feed valve 33 is a ball valve.

[0078] In some embodiments of the present invention, a cooling device 41 is provided on the outer wall of the degradation product storage tank 4, which can cool the temperature inside the degradation product storage tank to below 0°C.

[0079] In some embodiments of the present invention, the center of gravity of the polyester degradation reactor 2 is higher than that of the degradation product storage tank 4.

[0080] In another aspect, the present invention provides the application of the above-described reaction separation system apparatus in polyester degradation, comprising the following steps:

[0081] S1. Add polyester fragments, alcoholysis agent, and magnetic catalyst to a sealed polyester degradation reactor and react at 170-220℃ for 1-2 hours until the polyester is completely degraded to obtain a reaction solution.

[0082] S2. The reaction liquid enters the magnetic separation tube through the bottom outlet of the polyester degradation reactor and the discharge valve. The magnetic structure outside the magnetic separation tube is used to separate the magnetic catalyst in the reaction liquid to obtain a polyester degradation mixture.

[0083] S3. The polyester degradation mixture is transported to the degradation product storage tank, cooled by the cooling device outside the degradation product storage tank, and then transported to the separation and post-processing device for filtration and washing to obtain the solid filter cake.

[0084] S4. The solid filter cake is dried to obtain the degradation products. The filtrate is distilled to obtain the alcoholysis agent, which is then transported to the solvent recovery storage tank.

[0085] In some embodiments of the present invention, in step S1, the polyester is selected from one or more of polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyarylate, and polyurethane.

[0086] In some embodiments of the present invention, in step S1, the magnetic catalyst is selected from Fe3O4 nanoparticle dispersion, Co3O4 nanoparticle dispersion, ferrate (M x Fe 3-x O4 (M = Cu, Zn, Mg, Co, Ni) nanoparticle dispersions, wherein the average particle size is between 1-100 nm; preferably, the average particle size is between 1-30 nm. The dispersion should ideally be a catalyst with small particle size, high dispersibility, good magnetic response, and strong reactivity, which is beneficial for increasing the reaction rate and facilitating magnetic recovery of the catalyst.

[0087] In some embodiments of the present invention, in step S1, the mass ratio of polyester: alcoholysis agent: magnetic catalyst is 1:4-15:0.01-0.05. If the proportion of alcoholysis agent is too low, the degradation efficiency of the polyester will decrease, and the viscosity of the mixture will increase, which is not conducive to mass production. If the proportion of alcoholysis agent is too high, it will lead to solvent waste and increase the cost of subsequent alcoholysis agent recovery. If the catalyst content is too low, the catalytic effect on polyester degradation will be insignificant, which is not conducive to the reaction. If the catalyst content is too high, it will also lead to catalyst waste.

[0088] In some embodiments of the present invention, in step S2, the temperature inside the magnetic separation tube is 60-80°C. This is to prevent the precipitation of reaction products from affecting the adsorption and separation of the magnetic catalyst.

[0089] In some embodiments of the present invention, in step S3, the cooling device cooling refers to cooling the material in the degradation product storage tank to below 0°C.

[0090] In some embodiments of the present invention, in step S4, the drying temperature is 80-110°C.

[0091] In some embodiments of the present invention, in step S4, the alcoholysis agent obtained after distillation of the filtrate is returned to step S1 for recycling. The recycling of the alcoholysis agent helps reduce the raw material cost of the reaction and achieves green and sustainable utilization of the raw materials. The magnetic recovery system includes a solvent recovery tank, a magnetic separation tube, and a catalyst recovery tank, where the catalyst can be replenished.

[0092] Example 1

[0093] A method for degrading polyester using the reaction separation system of the present invention includes the following steps:

[0094] (1) Place 10g of PET polyester, 80g of ethylene glycol, and 70mg of CoFe2O4 nanoparticles with an average particle size of 10nm in a polyester degradation reactor with an aspect ratio of 2.5:1. Heat the system to 220℃ using a temperature control system and react for 1 hour. After the reaction, cool the solution to 70℃.

[0095] (2) Open the discharge valve and let the mixture flow into the magnetic separation tube (surface magnetic field strength 6000GS). Keep the mixture at a constant temperature of 70℃ and let it stand for 2 hours under the magnetic structure.

[0096] (3) Open the feed valve and let the solvent and degradation products flow into the degradation product storage tank, and cool it at 0°C for 24 hours; filter the degradation products;

[0097] (4) Remove the magnetic structure, rinse the magnetic separation tube with ethylene glycol, and collect the magnetic catalyst.

[0098] The PET degradation rate was 100%, the BHET yield was 91.2%, and the recovery rate of the CoFe2O4 magnetic nanoparticle catalyst was 97%.

[0099] Example 2

[0100] A method for degrading polyester using the reaction separation system of the present invention includes the following steps:

[0101] (1) Place 10g of PET polyester, 80g of ethylene glycol, and 200mg of Fe3O4 nanoparticles with an average particle size of 11nm in a polyester degradation reactor with an aspect ratio of 2.5:1. Heat the system to 220℃ using a temperature control system and react for 1 hour. After the reaction, cool the solution to 70℃.

[0102] (2) Open the discharge valve and let the mixture flow into the magnetic separation tube (surface magnetic field strength 6000GS). Keep the mixture at a constant temperature of 70℃ and let it stand for 2 hours under the magnetic structure.

[0103] (3) Open the feed valve and let the solvent and degradation products flow into the degradation product storage tank, and cool it at 0°C for 24 hours; filter the degradation products;

[0104] (4) Remove the magnetic structure, rinse the magnetic separation tube with ethylene glycol, and collect the magnetic catalyst.

[0105] The PET degradation rate was 100%, the BHET recovery rate was 90.5%, and the Fe3O4 magnetic nanoparticle catalyst recovery rate was 95%.

[0106] Example 3

[0107] A method for degrading polyester using the reaction separation system of the present invention includes the following steps:

[0108] (1) Place 10g of PET polyester, 80g of ethylene glycol, and 70mg of ZnFe2O4 nanoparticles with an average particle size of 8nm in a polyester degradation reactor with an aspect ratio of 2.5:1. Heat the system to 220℃ using a temperature control system and react for 1 hour. After the reaction, cool the solution to 70℃.

[0109] (2) Open the discharge valve and let the mixture flow into the magnetic separation tube (surface magnetic field strength 6000GS). Keep the mixture at a constant temperature of 70℃ and let it stand for 24 hours under the magnetic structure.

[0110] (3) Open the feed valve and let the solvent and degradation products flow into the degradation product storage tank, and cool it at 0°C for 24 hours; filter the degradation products;

[0111] (4) Remove the magnetic structure, rinse the magnetic separation tube with ethylene glycol, and collect the magnetic catalyst.

[0112] The PET degradation rate was 100%, the BHET recovery rate was 90.3%, and the recovery rate of the ZnFe2O4 magnetic nanoparticle catalyst was 85%.

[0113] Example 4

[0114] A method for degrading polyester using the reaction separation system of the present invention includes the following steps:

[0115] (1) Mix 10g of PET polyester, 80g of ethylene glycol, and 70mg of Zn with an average particle size of 11nm. 0.5 Co 0.5Fe2O4 nanoparticles were placed in a polyester degradation reactor with an aspect ratio of 2.5:1. The system was heated to 220°C using a temperature control system and reacted for 1 hour. After the reaction, the solution was cooled to 70°C.

[0116] (2) Open the discharge valve and let the mixture flow into the magnetic separation tube (surface magnetic field strength 6000GS). Keep the mixture at a constant temperature of 70℃ and let it stand for 3 hours under the magnetic structure.

[0117] (3) Open the feed valve to allow the solvent and degradation products to flow into the degradation product storage tank, and cool it at 0°C for 24 hours. Filter the degradation products;

[0118] (4) Remove the magnetic structure, rinse the magnetic separation tube with ethylene glycol, and collect the magnetic catalyst.

[0119] PET degradation rate was 100%, BHET yield was 91.4%, and Zn 0.5 Co 0.5 The recovery rate of the Fe2O4 magnetic nanoparticle catalyst was 96%.

[0120] Example 5

[0121] A method for degrading polyester using the reaction separation system of the present invention includes the following steps:

[0122] (1) Place 10g of PET polyester, 80g of ethylene glycol, and 70mg of CoFe2O4 nanoparticles with an average particle size of 50nm in a polyester degradation reactor with an aspect ratio of 2.5:1. Heat the system to 220℃ using a temperature control system and react for 2 hours. After the reaction, cool the solution to 70℃.

[0123] (2) Open the discharge valve and slowly let the mixture flow into the magnetic separation tube (surface magnetic field strength 6000GS). Keep the mixture at a constant temperature of 70℃ and separate the catalyst under continuous flow conditions, controlling the liquid residence time to be greater than 0.5 hours.

[0124] (3) After the solvent and degradation products flow into the degradation product storage tank, the tank is cooled at 0°C for 24 hours. The degradation products are then filtered.

[0125] (4) Remove the magnetic structure, rinse the magnetic separation tube with ethylene glycol, and collect the magnetic catalyst.

[0126] The PET degradation rate was 100%, the BHET yield was 92.4%, and the recovery rate of the CoFe2O4 magnetic nanoparticle catalyst was 98%.

[0127] Example 6

[0128] A method for degrading polyester using the reaction separation system of the present invention includes the following steps:

[0129] (1) Place 10g of PET polyester, 80g of butanediol, and 70mg of CoFe2O4 nanoparticles with an average particle size of 50nm in a polyester degradation reactor with an aspect ratio of 2.5:1. Heat the system to 240℃ using a temperature control system and react for 2 hours. After the reaction, cool the solution to 70℃.

[0130] (2) Open the discharge valve and slowly let the mixture flow into the magnetic separation tube (surface magnetic field strength 6000GS). Keep the mixture at a constant temperature of 70℃ and separate the catalyst under continuous flow conditions, controlling the liquid residence time to be greater than 0.5 hours.

[0131] (3) After the solvent and degradation products flow into the degradation product storage tank, they are cooled at 0°C for 24 hours; the degradation products are then filtered.

[0132] (4) Remove the magnetic structure, rinse the magnetic separation tube with ethylene glycol, and collect the magnetic catalyst.

[0133] The PET degradation rate was 100%, the BHET recovery rate was 91.7%, and the recovery rate of the CoFe2O4 magnetic nanoparticle catalyst was 97%.

[0134] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is impossible to exhaustively list all embodiments here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A reactive separation system apparatus for polyester degradation, characterized by: The device comprises a solvent storage tank, a first conveying pump, a polyester degradation reactor, a magnetic separation tube, a degradation product storage tank, a separation and post-treatment tank, a solvent recovery storage tank, a second conveying pump, a catalyst recovery tank and a third conveying pump. The outlet of the solvent storage tank is connected to the inlet of the first conveying pump through a pipeline. The outlet of the first conveying pump is connected to the inlet of the polyester degradation reactor through a pipeline. The bottom outlet of the polyester degradation reactor is connected to the inlet of the magnetic separation tube through a pipeline. The outlet of the magnetic separation tube is connected to the inlet of the degradation product storage tank through a pipeline. The bottom outlet of the degradation product storage tank is connected to the inlet of the separation and post-treatment tank through a pipeline. The outlet of the separation and post-treatment tank is connected to the inlet of the solvent recovery storage tank through a pipeline. The solvent recovery storage tank is connected to the second conveying pump through a pipeline. The outlet of the second conveying pump is connected to the pipeline between the magnetic separation tube and the degradation product storage tank. The pipeline between the polyester degradation reactor and the magnetic separation tube is connected to the catalyst recovery tank. The catalyst recovery tank is connected to the third conveying pump. The outlet of the third conveying pump is connected to the polyester degradation reactor through a pipeline.

2. The apparatus for the reaction separation system for polyester degradation according to claim 1, characterized by: The polyester degradation reactor is provided with a stirring device, and the stirring rate of the stirring device is 100-500 r / min.

3. The apparatus for the reaction separation system for polyester degradation according to claim 1, characterized by: A discharge valve is arranged on the pipeline between the polyester degradation reactor and the magnetic separation tube, and the discharge valve is a spherical valve.

4. The apparatus for the reaction separation system for polyester degradation according to claim 3, characterized by: The magnetic separation tube is provided with a constant temperature system.

5. The reactive separation system apparatus for polyester degradation of claim 1, wherein: The magnetic separation tube is provided with a magnetic structure, which is a permanent magnet or an electromagnet, and the magnetic structure is a middle-split cylindrical structure, and the inner diameter of the cylindrical structure is the same as the outer diameter of the magnetic separation tube.

6. The reactive separation system apparatus for polyester degradation of claim 1, wherein: The surface magnetic field strength of the magnetic structure is greater than 6000 GS, and the magnetic separation tube is a non-magnetic metal tube or a quartz tube.

7. The system of claim 1, wherein: A feeding valve is arranged on the pipeline between the magnetic separation tube and the degradation product storage tank, and the feeding valve is a spherical valve.

8. The system for the degradation of polyesters by reaction separation according to claim 1, characterized in that: A cooling device is arranged on the outer wall of the degradation product storage tank, and the cooling device can cool the temperature in the degradation product storage tank to below 0℃.

9. Use of a reaction separation system device according to any one of claims 1-8 for degradation of polyesters, characterized by The height of the gravity center of the polyester degradation reactor from the ground is higher than the height of the gravity center of the degradation product storage tank from the ground. The device comprises the following steps: S1, polyester fragments, alcoholysis agent and magnetic catalyst are added into a closed polyester degradation reactor, and reaction is carried out at a temperature of 170-220℃ for 1-2 hours until the polyester is completely degraded to obtain a reaction liquid; S2, the reaction liquid is discharged from the bottom outlet of the polyester degradation reactor, enters the magnetic separation tube through the discharge valve, and the magnetic catalyst in the reaction liquid is separated by using the magnetic structure outside the magnetic separation tube to obtain a polyester degradation mixture; S3, the polyester degradation mixture is transported to the degradation product storage tank, cooled by the cooling device outside the degradation product storage tank, and then transported to a separation and post-treatment device for filtration and washing to obtain a solid filter cake; 10. Use according to claim 9, characterized in that: S4, the solid filter cake is dried to obtain a degradation product, and the filtrate is distilled to obtain an alcoholysis agent, which is transported to a solvent recovery storage tank. In step S1, the polyester is selected from one or more of polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyarylate and polyurethane. In step S1, the magnetic catalyst is selected from one or more of Fe3O4 nanoparticle dispersion, Co3O4 nanoparticle dispersion, ferrite nanoparticle dispersion, with an average particle size of 1-100 nm; ferrite refers to M x Fe 3-x O4, M = Cu, Zn, Mg, Co, Ni; The mass ratio of the polyester: alcoholysis agent: magnetic catalyst in step S1 is 1:4-15:0.01-0.

05.

11. Use according to claim 9, characterized in that: The temperature in the magnetic separation tube in step S2 is 60-80℃. The cooling device in step S3 is used to cool the stream in the degradation product storage tank to below 0℃. The drying temperature in step S4 is 80-110℃. The filtrate obtained after distillation in step S4 is returned to step S1 for recycling.

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