PETG oligomer continuous recovery polymerization production system and method

Abstract

The invention discloses a PETG oligomer continuous recovery polymerization production system and method, and relates to the technical field of PETG production, in particular to a PETG oligomer continuous recovery polymerization production system and method, which comprises an oligomer recovery unit, a polymerization reaction unit, a separation and purification unit, an online monitoring unit and a control system. According to the invention, efficient recovery of the PETG oligomer is realized, the recovery rate of the oligomer and the conversion rate and yield of polymerization reaction are improved, raw material waste and energy consumption are reduced, and the requirements of an efficient and low-energy-consumption production system are met.

Description

Technical Field

[0001] The invention relates to the technical field of PETG production, in particular to a PETG oligomer continuous recovery polymerization production system and method. Background Art

[0002] PETG (polyethylene terephthalate-1,4-cyclohexanedimethanol) is an engineering plastic with excellent performance, which is widely used in packaging, medical devices and 3D printing. In the production process of PETG, some oligomers are produced due to the start-up and shutdown or vacuum system. These oligomers have the characteristics of low molecular weight and viscosity and need to be recycled. However, the recycling of PETG has always been a challenge faced by the industry. Traditional PETG recycling technology is mainly divided into two categories: physical recycling and chemical recycling.

[0003] Physical recycling method: Physical recycling mainly processes waste PETG through mechanical separation, cleaning and granulation. Although this method is simple, it has many problems, such as the introduction of impurities during the recycling process, which leads to a decline in product quality; as the number of recycling increases, the molecular weight and viscosity of PETG decrease significantly, limiting its application in high-end products; physical recycling cannot effectively remove harmful substances, such as acetaldehyde, which may cause potential harm to the environment and human health.

[0004] Chemical recycling method: Chemical recycling degrades PETG into oligomers or monomers and then repolymerizes them, but there are also some problems, such as: traditional chemical recycling processes usually require high temperature and high pressure conditions, and have high energy consumption; some chemical recycling methods require the use of a large amount of catalysts, which increases production costs and post-processing difficulties; by-products may be produced during the chemical recycling process, affecting the recycling efficiency and product quality.

[0005] After searching, a method for preparing PETG from PETG and waste PET polyester with publication number CN114853991A was found, and the publication date is August 5, 2022. The patent proposes to depolymerize PET (polyethylene terephthalate) waste polyester raw materials to decompose them into bis(hydroxyethyl) terephthalate (BHET); then undergo an ester exchange reaction with methanol (MEOH) to generate the intermediate molecule DMT (dimethyl terephthalate); purify the generated DMT; after purification, the refined DMT is esterified with 1,4-cyclohexanedimethanol (CHDM) and ethylene glycol (EG) to form bis(hydroxymethyl)cyclohexylmethyl terephthalate (BHCT) and bis(hydroxyethyl) terephthalate (BHET); and then polymerize BHET and BHCT to generate a macromolecular chain PETG polymer. However, this method requires the use of methanol for alcoholysis, and then the process is carried out under high temperature (above 200°C) and high pressure (above 0.5MPa), which consumes a lot of energy and is complicated. In addition, a large amount of methanol is required during the depolymerization process, which increases the production cost and the complexity of post-processing.

[0006] After searching, a method for recycling and degrading PETG with publication number CN113277928A was found, and the publication date is August 20, 2021. The patent proposes to crush the PETG recycled material twice, hydrolyze it in a potassium hydroxide aqueous solution, and add toluene for extraction, and divide it into an organic phase and an aqueous phase. The organic phase enters the distillation tower to obtain ethylene glycol, toluene, and 1,4-cyclohexanedimethanol. After filtering the aqueous phase, anhydrous DMF and trimethoxysilyl chloride are added to produce terephthalic acid di(trimethoxysilane). The process of this method is relatively complicated, and the use of organic substances such as toluene and DMF increases the complexity of subsequent processing.

[0007] After searching, a method for preparing chemically regenerated PETG polyester with a publication number of CN114989400A was found, and the publication date is September 2, 2022. A method for preparing chemically regenerated PETG polyester is provided, and the main process is: after the PET polyester waste is crushed, it is alcoholyzed twice under the conditions of diols and catalysts, and then esterified at a temperature of 200-260°C. The esterified product is polycondensed at 260-280°C and under the action of a catalyst in a pressure range of 0.1-10kPa to obtain PETG. This process requires two alcoholysises, the process is relatively complicated, and it is an intermittent operation without continuity.

[0008] The above problems show that the existing PETG recovery methods have problems such as low recovery efficiency, increased production costs and post-processing complexity, discontinuous intermittent operation, etc. Therefore, the present invention proposes a PETG oligomer continuous recovery polymerization production system and method, which achieves efficient depolymerization and repolymerization of PETG at lower temperature and pressure by optimizing reaction conditions and process flow, and significantly reduces energy consumption and production costs. Summary of the invention

[0009] The present invention provides a PETG oligomer continuous recovery polymerization production system and method, which solves the problems of low recovery efficiency, increased production cost and post-processing complexity, discontinuous intermittent operation, etc. in the existing PETG recovery method. The present invention aims to provide a novel PETG oligomer continuous recovery polymerization production system and method with good oligomer recovery effect, high polymerization efficiency, simple system structure, simple operation, and low energy consumption, thereby improving product quality and production efficiency and meeting the needs of modern industry.

[0010] A PETG oligomer continuous recovery polymerization production system and method, comprising an oligomer recovery unit, a polymerization reaction unit, a separation and purification unit, an online monitoring unit and a control system, wherein the oligomer recovery unit is connected to the polymerization reaction unit and the separation and purification unit, the separation and purification unit is connected to the polymerization reaction unit, the online monitoring unit is respectively connected to the oligomer recovery unit, the polymerization reaction unit and the separation and purification unit, and the control system is respectively electrically connected to the oligomer recovery unit, the polymerization reaction unit, the separation and purification unit and the online monitoring unit.

[0011] The oligomer recovery unit includes a pretreatment device, a flash tower, a condenser and a collection tank. The pretreatment device is connected to the flash tower through a pipeline, the top of the flash tower is connected to the condenser through a pipeline, the bottom of the condenser is connected to the collection tank through a pipeline, and the outlet of the collection tank is connected to the inlet of the polymerization reaction unit through a pipeline. The pretreatment device is used to remove macromolecular impurities in the oligomer, the flash tower is used to separate small molecular substances in the oligomer, the condenser is used to condense the separated small molecular substances, and the collection tank is used to collect the condensed oligomers.

[0012] The polymerization reaction unit includes a continuous reactor, a catalyst adding device and a temperature control device, wherein the continuous reactor is connected to the catalyst adding device through a pipeline, and the temperature control device is connected to the continuous reactor. The continuous reactor is used to carry out polymerization reaction at a constant temperature and pressure, the catalyst adding device is used to add catalyst at a specific time point, and the temperature control device is used to accurately control the reaction temperature to ensure the stable progress of the polymerization reaction.

[0013] The separation and purification unit includes an evaporator, a distillation tower and a filter. The evaporator is connected to the outlet of the polymerization reaction unit through a pipeline, the outlet of the evaporator is connected to the inlet of the distillation tower through a pipeline, the outlet of the distillation tower is connected to the inlet of the filter through a pipeline, and the outlet of the filter is connected to the inlet of the oligomer recovery unit through a pipeline. The evaporator is used to remove residual solvents in the polymer, the distillation tower is used to separate oligomers in the polymer, and the filter is used to remove solid impurities in the polymer.

[0014] The online monitoring unit includes a temperature sensor, a pressure sensor, a flow sensor and a mass flow controller. The temperature sensor, pressure sensor and flow sensor are respectively installed at key positions of the oligomer recovery unit, the polymerization reaction unit and the separation and purification unit. The mass flow controller is installed on each pipeline for real-time monitoring and control of the temperature, pressure, flow and mass flow of each link. The temperature sensor is used to monitor the temperature of each link in real time, the pressure sensor is used to monitor the pressure of each link in real time, the flow sensor is used to monitor the flow of each link in real time, and the mass flow controller is used to accurately control the flow of each link to ensure the stable operation of each unit.

[0015] The control system includes a central processing unit, a data storage device, a signal transceiver and a power management module. The central processing unit is connected to the data storage device through a data bus, and is used to store and process data collected by the online monitoring unit, and judge the system status and issue corresponding instructions according to preset algorithms and logics; the signal transceiver is connected to the central processing unit, and is used to receive and send command signals; the power management module is connected to the central processing unit, and is used to manage and distribute the power provided by the power module.

[0016] The structural composition, implementation mode and operating principle of the present invention are as follows:

[0017] 1. Oligomer recovery unit: After the oligomers pass through the pretreatment device to remove macromolecular impurities, they enter the flash tower, where the small molecular substances in the oligomers are evaporated by heating. The evaporated substances enter the condenser through the top pipe, condense into liquid in the condenser, and then flow into the collection tank. The oligomers in the collection tank are transported to the polymerization reaction unit through a pipeline for the next polymerization reaction.

[0018] 2. Polymerization reaction unit: The oligomer enters the continuous reactor through a pipeline. In the continuous reactor, the catalyst is added at a specific time point through the adding device, and the temperature control device adjusts the power of the heater to ensure a constant reaction temperature. Under constant temperature and pressure, the oligomer undergoes polymerization to generate high molecular weight PETG.

[0019] 3. Separation and purification unit: The mixture after the polymerization reaction enters the evaporator through a pipeline, and the evaporator removes the residual solvent in the mixture by heating. The mixture after the solvent is removed enters the distillation tower, where the oligomers are separated by distillation. The separated oligomers are returned to the oligomer recovery unit through a pipeline for reuse. The polymer after distillation enters the filter, where the solid impurities are removed by filtration to obtain high-purity PETG.

[0020] 4. Online monitoring unit: Temperature sensors, pressure sensors, and flow sensors are installed at key positions of the oligomer recovery unit, polymerization reaction unit, and separation and purification unit to monitor the temperature, pressure, and flow of each link in real time. Mass flow controllers are installed on each pipeline to accurately control the flow of each link according to the instructions of the central processor. The central processor receives real-time data from the sensor through the signal transceiver, determines the system status according to the preset algorithm and logic, and issues corresponding instructions to ensure the stable operation of each link.

[0021] 5. Control system: The central processor is connected to the data storage device through the data bus to store and process the data collected by the online monitoring unit. The system status is determined according to the preset algorithm and logic, and instructions are sent to each unit through the signal transceiver to ensure stable operation of the system. The power management module monitors the power status in real time to ensure that the system automatically switches to the backup power supply when the main power fails to maintain normal power supply.

[0022] Beneficial effects of the present invention:

[0023] 1. High efficiency of oligomer recovery: Through the combination of pretreatment device, flash tower, condenser and collection tank, efficient recovery of oligomers is achieved, the recovery rate of oligomers is improved, the waste of raw materials is reduced, and the production cost is reduced.

[0024] 2. Stable polymerization process: Through the combination of continuous reactor, catalyst adding device and temperature control device, the polymerization reaction is carried out stably, the conversion rate and yield of the polymerization reaction are improved, and the quality of the product is ensured.

[0025] 3. The system structure is simple and easy to operate: Through the optimized connection between the units and the real-time monitoring of the online monitoring unit, the system structure is simplified, the operation difficulty is reduced, the production efficiency is improved, the energy consumption is reduced, and the demand of modern industry for efficient and low-energy production systems is met. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the PETG oligomer continuous recycling polymerization production system;

[0027] Figure 2 is a detailed structural diagram of the oligomer recovery unit;

[0028] Figure 3 It is a detailed structural schematic diagram of the polymerization reaction unit;

[0029] Figure 4 It is a detailed structural schematic diagram of the separation and purification unit;

[0030] Figure 5 It is a detailed structural diagram of the online monitoring unit and control system.

[0031] In the figure: 1. oligomer recovery unit; 2. polymerization reaction unit; 3. separation and purification unit; 4. online monitoring unit; 5. control system; 11. pretreatment device; 12. flash tower; 13. condenser; 14. collection tank; 21. continuous reactor; 22. catalyst adding device; 23. temperature control device; 31. evaporator; 32. distillation tower; 33. filter; 41. temperature sensor; 42. pressure sensor; 43. flow sensor; 44. mass flow controller; 51. central processing unit; 52. data storage device; 53. signal transceiver; 54. power management module. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0033] The embodiment of the present invention solves the problems of low oligomer recovery efficiency, unstable polymerization process, complex equipment, high operation difficulty, high energy consumption, etc. in the existing PETG production system by providing a PETG oligomer continuous recovery polymerization production system and method. The present invention aims to provide a new PETG production system and method with good oligomer recovery effect, high polymerization efficiency, simple system structure, simple operation, and low energy consumption, so as to improve product quality and production efficiency and meet the needs of modern industry.

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] See also Figures 1 to 5 A PETG oligomer continuous recovery polymerization production system and method, comprising an oligomer recovery unit 1, a polymerization reaction unit 2, a separation and purification unit 3, an online monitoring unit 4 and a control system 5. The oligomer recovery unit 1 is connected to the polymerization reaction unit 2 and the separation and purification unit 3, the separation and purification unit 3 is connected to the polymerization reaction unit 2, the online monitoring unit 4 is respectively connected to the oligomer recovery unit 1, the polymerization reaction unit 2, and the separation and purification unit 3, and the control system 5 is respectively electrically connected to the oligomer recovery unit 1, the polymerization reaction unit 2, the separation and purification unit 3 and the online monitoring unit 4.

[0036] Oligomer Recovery Unit 1 Figure 2The oligomer recovery unit 1 includes a pretreatment device 11, a flash tower 12, a condenser 13 and a collection tank 14. The pretreatment device 11 is connected to the flash tower 12 through a pipeline, the top of the flash tower 12 is connected to the condenser 13 through a pipeline, the bottom of the condenser 13 is connected to the collection tank 14 through a pipeline, and the outlet of the collection tank 14 is connected to the inlet of the polymerization reaction unit 2 through a pipeline. The pretreatment device 11 is used to remove macromolecular impurities in the oligomers, the flash tower 12 is used to separate small molecular substances in the oligomers, the condenser 13 is used to condense the separated small molecular substances, and the collection tank 14 is used to collect the condensed oligomers.

[0037] In specific operation, after the oligomer passes through the pretreatment device 11 to remove macromolecular impurities, it enters the flash tower 12. In the flash tower 12, the small molecular substances in the oligomer are evaporated by heating, and the evaporated substances enter the condenser 13 through the top pipe, condense into liquid in the condenser 13, and then flow into the collection tank 14. The oligomers in the collection tank 14 are transported to the polymerization reaction unit 2 through a pipeline for the next polymerization reaction.

[0038] Polymerization reaction unit 2 Figure 3 The polymerization reaction unit 2 includes a continuous reactor 21, a catalyst adding device 22 and a temperature control device 23. The continuous reactor 21 is connected to the catalyst adding device 22 through a pipeline, and the temperature control device 23 is connected to the continuous reactor 21. The continuous reactor 21 is used to carry out polymerization reaction at a constant temperature and pressure, the catalyst adding device 22 is used to add catalyst at a specific time point, and the temperature control device 23 is used to accurately control the reaction temperature to ensure the stable progress of the polymerization reaction.

[0039] In specific operation, the oligomer enters the continuous reactor 21 through a pipeline, and the catalyst is added at a specific time point in the continuous reactor 21 through the catalyst adding device 22. The temperature control device 23 ensures a constant reaction temperature by adjusting the power of the heater. Under constant temperature and pressure, the oligomer undergoes a polymerization reaction to generate high molecular weight PETG.

[0040] Separation and purification unit 3 Figure 4, the separation and purification unit 3 includes an evaporator 31, a distillation tower 32 and a filter 33. The evaporator 31 is connected to the outlet of the polymerization reaction unit 2 through a pipeline, the outlet of the evaporator 31 is connected to the inlet of the distillation tower 32 through a pipeline, the outlet of the distillation tower 32 is connected to the inlet of the filter 33 through a pipeline, and the outlet of the filter 33 is connected to the inlet of the oligomer recovery unit 1 through a pipeline. The evaporator 31 is used to remove the residual solvent in the polymer, the distillation tower 32 is used to separate the oligomers in the polymer, and the filter 33 is used to remove the solid impurities in the polymer. During specific operation, the mixture after the polymerization reaction enters the evaporator 31 through a pipeline, and the evaporator 31 removes the residual solvent in the mixture by heating. The mixture after the solvent is removed enters the distillation tower 32, in which the oligomers are separated by distillation, and the separated oligomers are returned to the oligomer recovery unit 1 through a pipeline for reuse. The polymer after distillation enters the filter 33, in which the solid impurities therein are removed by filtration to obtain high-purity PETG.

[0041] Online Monitoring Unit 4 See Figure 5 , the online monitoring unit 4 includes a temperature sensor 41, a pressure sensor 42, a flow sensor 43 and a mass flow controller 44. The temperature sensor 41, the pressure sensor 42 and the flow sensor 43 are respectively installed at key positions of the oligomer recovery unit 1, the polymerization reaction unit 2 and the separation and purification unit 3, and the mass flow controller 44 is installed on each pipeline for real-time monitoring and control of the temperature, pressure, flow and mass flow of each link. The temperature sensor 41 is used to monitor the temperature of each link in real time, the pressure sensor 42 is used to monitor the pressure of each link in real time, the flow sensor 43 is used to monitor the flow of each link in real time, and the mass flow controller 44 is used to accurately control the flow of each link to ensure the stable operation of each unit.

[0042] During specific operation, the temperature sensor 41, the pressure sensor 42, and the flow sensor 43 are respectively installed at key positions of the oligomer recovery unit 1, the polymerization reaction unit 2, and the separation and purification unit 3 to monitor the temperature, pressure, and flow of each link in real time. The mass flow controller 44 is installed on each pipeline to accurately control the flow of each link according to the instructions of the central processor 51. The central processor 51 receives the real-time data of the sensor through the signal transceiver 53, determines the system status according to the preset algorithm and logic, and issues corresponding instructions to ensure the stable operation of each link.

[0043] Control system 5 See Figure 5The control system 5 includes a central processor 51, a data storage 52, a signal transceiver 53 and a power management module 54. The central processor 51 is connected to the data storage 52 via a data bus, and is used to store and process the data collected by the online monitoring unit 4, and judge the system state according to the preset algorithm and logic and issue corresponding instructions; the signal transceiver 53 is connected to the central processor 51, and is used to receive and send instruction signals; the power management module 54 is connected to the central processor 51, and is used to manage and distribute the power provided by the power module.

[0044] During specific operation, the central processor 51 is connected to the data storage 52 via the data bus to store and process the data collected by the online monitoring unit 4. The system status is determined according to the preset algorithm and logic, and instructions are sent to each unit through the signal transceiver 53 to ensure stable operation of the system. The power management module 54 monitors the power status in real time to ensure that the main power supply fails and automatically switches to the backup power supply to maintain normal power supply of the system.

[0045] Operation principle and operation process In specific operation, the oligomer first passes through the pretreatment device 11 to remove macromolecular impurities and then enters the flash tower 12, where the small molecular substances in the oligomer are evaporated by heating. The evaporated substances enter the condenser 13 through the pipe at the top, condense into liquid in the condenser 13, and then flow into the collection tank 14. The oligomers in the collection tank 14 are transported to the polymerization reaction unit 2 through the pipeline.

[0046] In the polymerization reaction unit 2, the oligomer enters the continuous reactor 21 through a pipeline, and the catalyst is added at a specific time point in the continuous reactor 21 through the catalyst adding device 22. The temperature control device 23 ensures a constant reaction temperature by adjusting the power of the heater. Under constant temperature and pressure, the oligomer undergoes a polymerization reaction to generate high molecular weight PETG.

[0047] The resulting mixture enters the separation and purification unit 3 through a pipeline. After the residual solvent is removed in the evaporator 31, it enters the distillation tower 32, where the oligomers are separated and returned to the oligomer recovery unit 1 for reuse. The polymer after distillation enters the filter 33, where the solid impurities are removed to obtain high-purity PETG.

[0048] The temperature sensor 41, pressure sensor 42, and flow sensor 43 in the online monitoring unit 4 are installed at key positions to monitor the temperature, pressure, and flow of each link in real time. The mass flow controller 44 is installed on each pipeline to accurately control the flow of each link according to the instructions of the central processor 51. The central processor 51 receives the real-time data of the sensor through the signal transceiver 53, and judges the system status according to the preset algorithm and logic and issues corresponding instructions to ensure the stable operation of each link.

[0049] The central processor 51 in the control system 5 is connected to the data storage 52 through the data bus to store and process the data collected by the online monitoring unit 4. The system status is determined according to the preset algorithm and logic, and instructions are sent to each unit through the signal transceiver 53 to ensure stable operation of the system. The power management module 54 monitors the power status in real time to ensure that the backup power supply is automatically switched to when the main power supply fails to maintain normal power supply of the system.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the descriptions in the above embodiments and the specification are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A PETG oligomer continuous recovery polymerization production system, characterized in that, The invention comprises an oligomer recovery unit (1), a polymerization reaction unit (2), a separation and purification unit (3), an online monitoring unit (4) and a control system (5); the oligomer recovery unit (1) is connected to the polymerization reaction unit (2) and the separation and purification unit (3); the separation and purification unit (3) is connected to the polymerization reaction unit (2); the online monitoring unit (4) is respectively connected to the oligomer recovery unit (1), the polymerization reaction unit (2) and the separation and purification unit (3); and the control system (5) is respectively electrically connected to the oligomer recovery unit (1), the polymerization reaction unit (2), the separation and purification unit (3) and the online monitoring unit (4).

2. The PETG oligomer continuous recovery polymerization production system according to claim 1, characterized in that, The oligomer recovery unit (1) comprises a pretreatment device (11), a flash tower (12), a condenser (13) and a collection tank (14); the pretreatment device (11) is connected to the flash tower (12) via a pipeline; the top of the flash tower (12) is connected to the condenser (13) via a pipeline; the bottom of the condenser (13) is connected to the collection tank (14) via a pipeline; and the outlet of the collection tank (14) is connected to the inlet of the polymerization reaction unit (2) via a pipeline.

3. The PETG oligomer continuous recovery polymerization production system according to claim 1, characterized in that, The polymerization reaction unit (2) comprises a continuous reactor (21), a catalyst adding device (22) and a temperature control device (23); the continuous reactor (21) is connected to the catalyst adding device (22) via a pipeline, and the temperature control device (23) is connected to the continuous reactor (21).

4. The PETG oligomer continuous recovery polymerization production system according to claim 1, characterized in that, The separation and purification unit (3) comprises an evaporator (31), a distillation tower (32) and a filter (33); the evaporator (31) is connected to the outlet of the polymerization reaction unit (2) via a pipeline; the outlet of the evaporator (31) is connected to the inlet of the distillation tower (32) via a pipeline; the outlet of the distillation tower (32) is connected to the inlet of the filter (33) via a pipeline; and the outlet of the filter (33) is connected to the inlet of the oligomer recovery unit (1) via a pipeline.

5. The PETG oligomer continuous recovery polymerization production system according to claim 1, characterized in that, The online monitoring unit (4) comprises a temperature sensor (41), a pressure sensor (42), a flow sensor (43) and a mass flow controller (44); the temperature sensor (41), the pressure sensor (42) and the flow sensor (43) are respectively installed at key positions of the oligomer recovery unit (1), the polymerization reaction unit (2) and the separation and purification unit (3); and the mass flow controller (44) is installed on each pipeline.

6. The PETG oligomer continuous recovery polymerization production system according to claim 1, characterized in that, The control system (5) comprises a central processing unit (51), a data storage unit (52), a signal transceiver (53) and a power management module (54); the central processing unit (51) is connected to the data storage unit (52) via a data bus, the signal transceiver (53) is connected to the central processing unit (51), and the power management module (54) is connected to the central processing unit (51).

7. The PETG oligomer continuous recovery polymerization production system according to claim 1, characterized in that, The central processing unit (51) in the control system (5) is connected to the data storage (52) via a data bus, stores and processes the data collected by the online monitoring unit (4), determines the system status according to a preset algorithm and logic, and issues corresponding instructions.

8. A PETG oligomer continuous recovery polymerization production method, characterized in that, The following steps are involved: a. After the oligomers pass through the pretreatment device (11) to remove macromolecular impurities, they enter the flash tower (12); b. The small molecules in the oligomer are evaporated by heating in the flash tower (12), and the evaporated substances enter the condenser (13) through the top pipe; c. Condensed into liquid in the condenser (13), and then flows into the collection tank (14); d. The oligomers in the collection tank (14) are transported to the polymerization reaction unit (2) via a pipeline; e. The oligomers enter the continuous reactor (21) through a pipeline, and the catalyst is added at a specific time point through a catalyst addition device (22); f. The temperature control device (23) ensures a constant reaction temperature by adjusting the power of the heater; g. Under constant temperature and pressure, the oligomers undergo polymerization to generate high molecular weight PETG; h. The resulting mixture enters an evaporator (31) through a pipeline to remove residual solvent from the mixture; i. After the solvent is removed, the mixture enters a distillation column (32), and the oligomers are separated by distillation, and the separated oligomers are returned to the oligomer recovery unit (1) through a pipeline; j. The polymer after distillation enters the filter (33), where solid impurities are removed by filtration to obtain high-purity PETG.

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