Purification system of propylene glycol methyl ether acetate

Abstract

The present invention relates to the technical field of solvent purification, and discloses a propylene glycol methyl ether acetate purification control method and a propylene glycol methyl ether acetate purification process, the propylene glycol methyl ether acetate purification control system comprises a rectification device and a rectification control system, the rectification device comprises a rectification tower, a raw material preheater, a condenser, a reflux tank and a reboiler, the rectification control system comprises an environment temperature measuring unit, a tower top temperature measuring unit, a tower bottom temperature measuring unit, a feeding temperature measuring unit and a regulation and control module, the rectification control system is pre-trained with a parameter prediction model, and the parameter prediction model takes the environment temperature, the tower top temperature, the tower bottom temperature and the feeding temperature as input to output regulation and control parameters. The regulation and control parameters comprise the opening degree of a steam valve, the power of a condenser and the opening degree of a return valve, a primary distribution controlled parameter is obtained according to a preset distribution strategy, the primary distribution controlled parameter is specifically the optimized regulation and control parameter, and the tower top temperature is controlled within a preset tower top temperature range according to the primary distribution controlled parameter.

Description

Technical Field

[0001] The invention relates to the technical field of solvent purification, and in particular to a purification system for propylene glycol methyl ether acetate. Background Art

[0002] Propylene glycol methyl ether acetate (PGMEA), whose chemical name is 1-methoxy-2-propanol acetate, is a high-performance solvent widely used in coatings, inks, electronic chemicals and other fields. Due to its excellent solubility, low volatility, low toxicity and good stability, the application of PGMEA in semiconductor photoresists is particularly important. However, in the industrial production process, the obtained PGMEA often contains impurities such as moisture, unreacted raw materials and by-products. The presence of these impurities will have a negative impact on the performance and use of the product. Therefore, the development of an effective purification process is of vital importance to improve the quality and performance of PGMEA.

[0003] In order to ensure the purity and quality of PGMEA, researchers and engineers have been working hard to develop various purification technologies. Common purification methods include distillation, extraction and adsorption. Distillation is a method of volatilizing different components in a mixture at different temperatures by heating, and then separating them by condensation. By precisely controlling the distillation conditions, water and other volatile impurities can be effectively removed. Extraction uses the different solubility between solvents to separate the target compound from the mixture. Adsorption uses adsorbents such as activated carbon or molecular sieves to adsorb impurities on the surface or in the pores to achieve the purpose of purification.

[0004] In practical applications, the choice of purification process needs to comprehensively consider the cost, efficiency and quality requirements of the final product. For example, in the application of semiconductor photoresists, the purity requirements for PGMEA are extremely high, so a multi-stage purification process may be required to ensure that all potential impurities are effectively removed. In addition, the operating conditions, such as temperature, pressure and time, need to be strictly controlled during the purification process to avoid introducing new impurities or destroying the stability of PGMEA. In actual operation, the internal operation of the distillation tower can be kept stable by continuously controlling the top temperature, bottom temperature and reflux ratio of the tower. Conventional PID control systems are usually used for adjustment. However, this adjustment method has a certain hysteresis phenomenon, which takes a long time to reach equilibrium, affecting the purification quality. Summary of the invention

[0005] In view of the shortcomings of the prior art, the object of the present invention is to provide a purification system for propylene glycol methyl ether acetate.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A purification system for propylene glycol methyl ether acetate comprises a rectification device and a rectification control system, wherein the rectification device comprises a rectification tower, a raw material preheater, a condenser, a reflux tank and a reboiler, wherein a steam outlet and a reflux liquid pipe are arranged at the top of the rectification tower, the raw material preheater, the condenser and the reflux tank are connected in sequence through a pipeline between the steam outlet and the reflux liquid pipe, a reflux valve is arranged on the reflux liquid pipe, a raw material inlet pipe is arranged on the side wall of the rectification tower, the raw material inlet pipe is connected to the raw material preheater, the reboiler is installed at the bottom of the rectification tower, and a steam valve is arranged on the reboiler, wherein the steam valve is used to control the amount of steam entering the reboiler,

[0008] The distillation control system comprises

[0009] A recording module, wherein the recording module is configured with an operation database, wherein the operation database records a number of operation parameters and corresponding controlled variables, wherein the controlled variables include a condensation parameter, a reboiling parameter, and a reflux parameter, wherein the operation parameters are specifically a tower top temperature, a tower bottom temperature, and a reflux ratio when a steady state is reached in the distillation tower, and the operation database is obtained by pre-testing;

[0010] A pre-regulation module, after the distillation tower runs for a preset time according to the pre-regulation strategy, the pre-regulation module obtains the actual operating parameters of the distillation tower as reference operating parameters, compares the reference operating parameters with the preset parameter interval, and adjusts the controlled variables according to the allocation strategy to obtain a primary allocation controlled variable, and controls the reboiler, the condenser and the reflux valve according to the primary allocation controlled variable to make the distillation tower reach a stable state;

[0011] A re-regulation module is configured with a re-regulation allocation strategy, wherein the re-regulation allocation strategy obtains re-regulation operation parameters with the goal of reducing energy consumption, and controls the reboiler, condenser and reflux valve according to the re-regulation operation parameters.

[0012] Furthermore, the step of running the database pre-test includes:

[0013] Obtaining the set operating range of each operating parameter;

[0014] Taking one of the controlled variables as the quantitative variable, another controlled variable as the independent variable, and the remaining controlled variables as the dependent variables, the distillation tower is regulated and controlled, and the test operation parameters and the test controlled variables when the distillation tower is in a steady state are obtained;

[0015] The test operation parameters and corresponding test controlled variables that meet the set operation range are screened and recorded in the operation database.

[0016] Furthermore, the distillation control system includes an ambient temperature measuring unit, a tower top temperature measuring unit, a tower bottom temperature measuring unit, and a feed temperature measuring unit. The ambient temperature detection unit is used to detect the external ambient temperature, the tower top temperature detection unit is used to detect the tower top temperature, the tower bottom temperature detection unit is used to detect the tower bottom temperature, and the feed temperature sensor is used to detect the feed temperature.

[0017] The distillation control system is pre-trained with a parameter prediction model, which is trained with data from an operating database. The parameter prediction model takes ambient temperature, tower top temperature, tower bottom temperature, and feed temperature as input to output control parameters, and the control parameters include steam valve opening, condenser power, and reflux valve opening. A primary distribution controlled parameter is obtained according to a preset distribution strategy. The primary distribution controlled parameter is specifically an optimized control parameter. The tower top temperature is controlled within a preset tower top temperature range according to the primary distribution controlled parameter.

[0018] Furthermore, the parameter prediction model is pre-configured with several ambient standard temperatures and corresponding PID control parameters, and the PID control parameters are specifically process control parameters of steam valve opening, condenser power, and reflux valve opening under the PID control mode. The PID control parameters are pre-tested according to a preset adjustment strategy.

[0019] Furthermore, the adjustment strategy includes obtaining the difference between the tower top temperature and the preset top temperature and defining it as a reference difference. If the reference difference is greater than zero and the value is greater than the temperature difference threshold, a first operation is performed, and the first operation includes increasing the condenser power, and / or reducing the steam valve opening, and / or increasing the reflux valve opening; if the reference difference is less than zero and the value is less than the temperature difference threshold, a second operation is performed, and the second operation includes reducing the condenser power, and / or increasing the steam valve opening, and / or reducing the reflux valve opening. In the first operation and the second operation, the priority of the reflux valve opening adjustment is lower than the condenser power adjustment and the steam valve opening adjustment.

[0020] Furthermore, the allocation strategy includes obtaining the control parameters to obtain a mapping relationship between different control parameters and changes in the control parameters, and adjusting the control ratios of different control measures with the goal of reducing the necessary adjustment time. The necessary adjustment time is specifically the time required for stability to be achieved inside the distillation device. The control measures include condenser opening adjustment, steam valve opening adjustment and reflux valve opening adjustment.

[0021] Furthermore, the parameter prediction model generates several ambient reference temperatures based on several ambient standard temperatures, generates PID reference control parameters corresponding to the ambient reference temperatures based on the comparison rules between the PID control parameters and the ambient standard temperatures, uses the detected external ambient temperature as the ambient reference temperature and uses the corresponding PID reference control parameters as the PID control parameters.

[0022] Furthermore, the distillation control system is configured with an environmental reference temperature verification strategy, which includes obtaining the environmental reference temperature as the temperature to be verified, taking the corresponding PID reference control parameter as the control parameter to be verified, adjusting the control ratio of different control measures with the goal of reducing the necessary adjustment time to obtain the control ratio to be verified and the corresponding necessary adjustment time to be verified, generating a first-time distribution controlled parameter to be verified according to the control ratio to be verified, taking the first-time distribution controlled parameter to be verified as the execution parameter of the distillation device and calculating the actual adjustment time, comparing the actual adjustment time with the necessary adjustment time, if the error value is less than or equal to the preset error threshold, taking the environmental reference temperature as the environmental standard temperature and taking the PID reference control parameter as the PID control parameter, if the error value is greater than the preset error threshold, generating a test signal and testing the environmental reference temperature as the environmental standard temperature.

[0023] Furthermore, the purification system is configured with a pretreatment step, a distillation step, a drying step, a filtration step and an anion and cation removal step which are arranged in sequence, and the distillation step is performed by means of the distillation device and the distillation control system.

[0024] Furthermore, in the distillation step, the tower top temperature is controlled to be 70-80°C, the tower bottom temperature is controlled to be 120-130°C, the pressure is controlled to be -0.05 to -0.08 MPa, and the reflux ratio is controlled to be 3:1.

[0025] Beneficial effects of the present invention:

[0026] The present invention, through the provision of a raw material preheater, utilizes the steam material at the top of the distillation tower to preheat the raw material before entering the distillation tower, thereby improving energy efficiency. At the same time, the influence of the external ambient temperature, the tower top temperature, the tower bottom temperature and the feed temperature on the distillation process is considered, and the control parameters are predicted and optimized, so that the distillation tower can be controlled according to the controlled parameters allocated once so that the temperature and pressure inside the distillation tower can quickly meet the requirements, reduce the hysteresis caused by the conventional PID algorithm, shorten the equilibrium time, and thus improve the purification quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the distillation device in the present invention;

[0028] Figure 2 It is a schematic diagram of the purification process of propylene glycol methyl ether acetate in the present invention.

[0029] Figure numerals: 1, distillation tower; 2, raw material tank; 3, raw material preheater; 4, condenser; 5, reflux tank; 51, reflux valve; 6, reboiler; 61, steam valve. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] like Figure 1 As shown, a purification system of propylene glycol methyl ether acetate in this embodiment includes a rectification device and a rectification control system, wherein the rectification device includes a rectification tower, a raw material preheater, a condenser, a reflux tank and a reboiler, a steam outlet and a reflux liquid pipe are provided at the top of the rectification tower, and the raw material preheating tank, the condenser and the reflux tank are connected in sequence by a pipeline between the steam outlet and the reflux liquid pipe, a reflux valve is provided on the reflux liquid pipe, a raw material inlet pipe is provided on the side wall of the rectification tower, the raw material inlet pipe is connected to the raw material preheater, the reboiler is installed at the bottom of the rectification tower, and a steam valve is provided on the reboiler, and the steam valve is used to control the amount of steam entering the reboiler. The present invention uses the steam material at the top of the rectification tower to preheat the raw materials before entering the rectification tower through the setting of the raw material preheater, thereby improving energy efficiency.

[0034] The distillation control system comprises

[0035] A recording module, wherein the recording module is configured with an operation database, wherein the operation database records a number of operation parameters and corresponding controlled variables, wherein the controlled variables include a condensation parameter, a reboiling parameter, and a reflux parameter, wherein the operation parameters are specifically a tower top temperature, a tower bottom temperature, and a reflux ratio when a steady state is reached in the distillation tower, and the operation database is obtained by pre-testing;

[0036] A pre-regulation module, after the distillation tower runs for a preset time according to the pre-regulation strategy, the pre-regulation module obtains the actual operating parameters of the distillation tower as reference operating parameters, compares the reference operating parameters with the preset parameter interval, and adjusts the controlled variables according to the allocation strategy to obtain a primary allocation controlled variable, and controls the reboiler, the condenser and the reflux valve according to the primary allocation controlled variable to make the distillation tower reach a stable state;

[0037] A re-regulation module is configured with a re-regulation allocation strategy, wherein the re-regulation allocation strategy obtains re-regulation operation parameters with the goal of reducing energy consumption, and controls the reboiler, condenser and reflux valve according to the re-regulation operation parameters.

[0038] Furthermore, the step of running the database pre-test includes:

[0039] Obtain the set operating range of each operating parameter;

[0040] Taking one of the controlled variables as the quantitative variable, another controlled variable as the independent variable, and the remaining controlled variables as the dependent variables, the distillation tower is regulated and controlled, and the test operation parameters and the test controlled variables when the distillation tower is in a steady state are obtained;

[0041] The test operation parameters and corresponding test controlled variables that meet the set operation range are screened and recorded in the operation database.

[0042] Furthermore, the distillation control system includes an ambient temperature measuring unit, a tower top temperature measuring unit, a tower bottom temperature measuring unit, and a feed temperature measuring unit. The ambient temperature detection unit is used to detect the external ambient temperature, the tower top temperature detection unit is used to detect the tower top temperature, the tower bottom temperature detection unit is used to detect the tower bottom temperature, and the feed temperature sensor is used to detect the feed temperature.

[0043] The distillation control system is pre-trained with a parameter prediction model, which is trained with data from an operating database. The parameter prediction model takes ambient temperature, tower top temperature, tower bottom temperature, and feed temperature as input to output control parameters, and the control parameters include steam valve opening, condenser power, and reflux valve opening. A primary distribution controlled parameter is obtained according to a preset distribution strategy. The primary distribution controlled parameter is specifically an optimized control parameter. The tower top temperature is controlled within a preset tower top temperature range according to the primary distribution controlled parameter.

[0044] The distillation control system includes an ambient temperature measuring unit, a tower top temperature measuring unit, a tower bottom temperature measuring unit, a feed temperature measuring unit and a control module. The ambient temperature detection unit is used to detect the external ambient temperature, the tower top temperature detection unit is used to detect the tower top temperature, the tower bottom temperature detection unit is used to detect the tower bottom temperature, and the feed temperature sensor is used to detect the feed temperature.

[0045] The distillation control system is pre-trained with a parameter prediction model, which takes the ambient temperature, tower top temperature, tower bottom temperature, and feed temperature as input to output control parameters, and the control parameters include steam valve opening, condenser power, and reflux valve opening. A primary distribution controlled parameter is obtained according to a preset distribution strategy, and the primary distribution controlled parameter is specifically an optimized control parameter. The tower top temperature is controlled within a preset tower top temperature range according to the primary distribution controlled parameter. At the same time, the influence of the external ambient temperature, tower top temperature, tower bottom temperature, and feed temperature on the distillation process is considered, and the control parameters are predicted and optimized, so that the temperature and pressure inside the distillation tower can be quickly met by regulating the distillation tower according to the primary distribution controlled parameter, reducing the hysteresis caused by the conventional PID algorithm, shortening the equilibrium time, and thus improving the purification quality.

[0046] Furthermore, the parameter prediction model is pre-configured with several standard ambient temperatures and corresponding PID control parameters, wherein the PID control parameters are specifically process control parameters of steam valve opening, condenser power, and reflux valve opening under the PID control mode, and the PID control parameters are pre-tested according to a preset adjustment strategy. The process control parameters under the PID control mode can be obtained in advance using the parameter prediction model, and can be used to predict the process control parameters predicted under different ambient temperatures.

[0047] Further, the adjustment strategy includes obtaining the difference between the tower top temperature and the preset top temperature as a reference difference. If the reference difference is greater than zero and the value is greater than the temperature difference threshold, a first operation is performed, wherein the first operation includes increasing the condenser power, and / or reducing the steam valve opening, and / or increasing the reflux valve opening; if the reference difference is less than zero and the value is less than the temperature difference threshold, a second operation is performed, wherein the second operation includes reducing the condenser power, and / or increasing the steam valve opening, and / or reducing the reflux valve opening. In the first operation and the second operation, the priority of the reflux valve opening adjustment is lower than the condenser power adjustment and the steam valve opening adjustment. In the conventional PID control mode, the priorities of the condenser power, the steam valve opening, and the reflux valve opening are in a certain order. Among them, the steam valve opening and the condenser power will affect the temperature in the tower, including the tower top and tower bottom temperatures. When adjusting, the steam valve is usually opened and the condenser power is adjusted to the extreme value before the reflux valve opening adjustment is called, which also leads to a certain hysteresis in the adjustment process.

[0048] Furthermore, the allocation strategy includes obtaining the control parameters to obtain the mapping relationship between different control parameters and changes in the control parameters, and adjusting the control ratio of different control measures with the goal of reducing the necessary adjustment time. The necessary adjustment time is specifically the time required for the distillation device to reach stability. The control measures include condenser opening adjustment, steam valve opening adjustment, and reflux valve opening adjustment. The allocation strategy optimizes the adjustment process based on the synchronous influence of multiple control measures and shortens the necessary adjustment time by obtaining the mapping relationship and combining it with the synchronous adjustment of multiple control measures.

[0049] Furthermore, the parameter prediction model generates several environmental reference temperatures according to several environmental standard temperatures, generates PID reference control parameters corresponding to the environmental reference temperatures according to the comparison rules between the PID control parameters and the environmental standard temperatures, uses the detected external environmental temperature as the environmental reference temperature and uses the corresponding PID reference control parameters as the PID control parameters. Considering that the more environmental standard temperatures that need to be tested, the longer the test process, it can be used after a certain number of environmental standard temperatures are available. During use, the PID reference control parameters corresponding to the environmental reference temperature are generated according to the comparison rules, simplifying the test process. Then, the generated environmental reference temperature and PID reference control parameters need to be verified, and the verification process is as follows:

[0050] Furthermore, the distillation control system is configured with an environmental reference temperature verification strategy, which includes obtaining the environmental reference temperature as the temperature to be verified, taking the corresponding PID reference control parameter as the control parameter to be verified, adjusting the control ratio of different control measures with the goal of reducing the necessary adjustment time to obtain the control ratio to be verified and the corresponding necessary adjustment time to be verified, generating a first-time distribution controlled parameter to be verified according to the control ratio to be verified, taking the first-time distribution controlled parameter to be verified as the execution parameter of the distillation device and calculating the actual adjustment time, comparing the actual adjustment time with the necessary adjustment time, if the error value is less than or equal to the preset error threshold, taking the environmental reference temperature as the environmental standard temperature and taking the PID reference control parameter as the PID control parameter, if the error value is greater than the preset error threshold, generating a test signal and testing the environmental reference temperature as the environmental standard temperature.

[0051] Furthermore, the purification system is configured with a pretreatment step, a distillation step, a drying step, a filtration step and anion and cation removal step arranged in sequence, and the distillation step is performed by the distillation device and the distillation control system. In this embodiment, the purification steps of propylene glycol methyl ether acetate include:

[0052] 1. Pretreatment: The industrial-grade PGMEA raw material is initially filtered through filter paper to remove suspended solid impurities.

[0053] 2. Distillation: A distillation tower with multi-stage plates is used to distill the pretreated PGMEA. During the distillation process, the top temperature is controlled at 70-80°C, the bottom temperature is controlled at 120-130°C, the pressure is -0.05 to -0.08MPa, and the reflux ratio is 3:1, so as to achieve efficient separation and purification of PGMEA. The distillation process has been optimized above and will not be repeated here.

[0054] 3. Drying: Dry the distilled PGMEA to remove the moisture. Molecular sieves, anhydrous magnesium sulfate and other desiccants can be used for drying, and the drying time is about 2 hours.

[0055] 4. Filtration: Filter the dried PGMEA through a 0.2 micron filter membrane to remove any tiny solid impurities that may exist.

[0056] 5. Anion and cation removal: remove anions and / or cations from PGMEA.

[0057] Through the above steps, high-purity propylene glycol methyl ether acetate products can be obtained to meet the needs of high-end application fields.

[0058] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A purification system for propylene glycol methyl ether acetate, characterized in that: The invention comprises a distillation device and a distillation control system, wherein the distillation device comprises a distillation tower, a raw material preheater, a condenser, a reflux tank and a reboiler, wherein a steam outlet and a reflux liquid pipe are arranged on the top of the distillation tower, the raw material preheater, the condenser and the reflux tank are connected in sequence through a pipeline between the steam outlet and the reflux liquid pipe, a reflux valve is arranged on the reflux liquid pipe, a raw material inlet pipe is arranged on the side wall of the distillation tower, the raw material inlet pipe is connected to the raw material preheater, the reboiler is installed at the bottom of the distillation tower, a steam valve is arranged on the reboiler, and the steam valve is used to control the amount of steam entering the reboiler, The distillation control system comprises A recording module, wherein the recording module is configured with an operation database, wherein the operation database records a number of operation parameters and corresponding controlled variables, wherein the controlled variables include a condensation parameter, a reboiling parameter, and a reflux parameter, wherein the operation parameters are specifically a tower top temperature, a tower bottom temperature, and a reflux ratio when a steady state is reached in the distillation tower, and the operation database is obtained by pre-testing; A pre-regulation module, after the distillation tower runs for a preset time according to the pre-regulation strategy, the pre-regulation module obtains the actual operating parameters of the distillation tower as reference operating parameters, compares the reference operating parameters with the preset parameter interval, and adjusts the controlled variables according to the allocation strategy to obtain a primary allocation controlled variable, and controls the reboiler, the condenser and the reflux valve according to the primary allocation controlled variable to make the distillation tower reach a stable state; A re-regulation module is configured with a re-regulation allocation strategy, wherein the re-regulation allocation strategy obtains re-regulation operation parameters with the goal of reducing energy consumption, and controls the reboiler, condenser and reflux valve according to the re-regulation operation parameters.

2. The purification system of propylene glycol methyl ether acetate according to claim 1, characterized in that: The step of running the database pre-test comprises: Obtaining the set operating range of each operating parameter; Taking one of the controlled variables as the quantitative variable, another controlled variable as the independent variable, and the remaining controlled variables as the dependent variables, the distillation tower is regulated and controlled, and the test operation parameters and the test controlled variables when the distillation tower is in a steady state are obtained; The test operation parameters and corresponding test controlled variables that meet the set operation range are screened and recorded in the operation database.

3. The purification system of propylene glycol methyl ether acetate according to claim 1, characterized in that: The distillation control system comprises an ambient temperature measuring unit, a tower top temperature measuring unit, a tower bottom temperature measuring unit, and a feed temperature measuring unit. The ambient temperature detection unit is used to detect the external ambient temperature, the tower top temperature detection unit is used to detect the tower top temperature, the tower bottom temperature detection unit is used to detect the tower bottom temperature, and the feed temperature sensor is used to detect the feed temperature. The distillation control system is pre-trained with a parameter prediction model, which is trained with data from an operating database. The parameter prediction model takes ambient temperature, tower top temperature, tower bottom temperature, and feed temperature as input to output control parameters, and the control parameters include steam valve opening, condenser power, and reflux valve opening. A primary distribution controlled parameter is obtained according to a preset distribution strategy. The primary distribution controlled parameter is specifically an optimized control parameter. The tower top temperature is controlled within a preset tower top temperature range according to the primary distribution controlled parameter.

4. The purification system of propylene glycol methyl ether acetate according to claim 3, characterized in that: The parameter prediction model is pre-configured with several ambient standard temperatures and corresponding PID control parameters. The PID control parameters are specifically process control parameters of steam valve opening, condenser power, and reflux valve opening under the PID control mode. The PID control parameters are pre-tested according to a preset adjustment strategy.

5. The purification system of propylene glycol methyl ether acetate according to claim 4, characterized in that: The adjustment strategy includes obtaining the difference between the tower top temperature and the preset top temperature and defining it as a reference difference. If the reference difference is greater than zero and the value is greater than the temperature difference threshold, a first operation is performed, and the first operation includes increasing the condenser power, and / or reducing the steam valve opening, and / or increasing the reflux valve opening; if the reference difference is less than zero and the value is less than the temperature difference threshold, a second operation is performed, and the second operation includes reducing the condenser power, and / or increasing the steam valve opening, and / or reducing the reflux valve opening. In the first operation and the second operation, the priority of the reflux valve opening adjustment is lower than the condenser power adjustment and the steam valve opening adjustment.

6. The purification system of propylene glycol methyl ether acetate according to claim 5, characterized in that: The allocation strategy includes obtaining the control parameters to obtain the mapping relationship between different control measures and changes in the control parameters, and adjusting the control ratios of different control measures with the goal of reducing the necessary adjustment time. The necessary adjustment time is specifically the time required for stability to be achieved inside the distillation device. The control measures include condenser opening adjustment, steam valve opening adjustment and reflux valve opening adjustment.

7. The purification system of propylene glycol methyl ether acetate according to claim 6, characterized in that: The parameter prediction model generates several ambient reference temperatures according to several ambient standard temperatures, generates PID reference control parameters corresponding to the ambient reference temperatures according to the comparison rules between the PID control parameters and the ambient standard temperatures, uses the detected external ambient temperature as the ambient reference temperature and uses the corresponding PID reference control parameters as the PID control parameters.

8. The purification system of propylene glycol methyl ether acetate according to claim 7, characterized in that: The distillation control system is configured with an environmental reference temperature verification strategy, which includes obtaining an environmental reference temperature as a temperature to be verified, using a corresponding PID reference control parameter as a control parameter to be verified, adjusting the control ratio of different control measures with the goal of reducing the necessary adjustment time to obtain the control ratio to be verified and the corresponding necessary adjustment time to be verified, generating a first-time distribution controlled parameter to be verified according to the control ratio to be verified, using the first-time distribution controlled parameter to be verified as an execution parameter of the distillation device and calculating the actual adjustment time, comparing the actual adjustment time with the necessary adjustment time, and if the error value is less than or equal to a preset error threshold, using the environmental reference temperature as the environmental standard temperature and using the PID reference control parameter as the PID control parameter; if the error value is greater than the preset error threshold, generating a test signal and testing the environmental reference temperature as the environmental standard temperature.

9. The purification system of propylene glycol methyl ether acetate according to claim 1, characterized in that: The purification system is equipped with a pretreatment step, a distillation step, a drying step, a filtering step and an anion and cation removal step which are arranged in sequence, and the distillation step is performed by the distillation device and the distillation control system.

10. The purification system of propylene glycol methyl ether acetate according to claim 9, characterized in that: In the distillation step, the tower top temperature is controlled to be 70-80°C, the tower bottom temperature is controlled to be 120-130°C, the pressure is controlled to be -0.05 to -0.08MPaMPa, and the reflux ratio is controlled to be 3:1.

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