Control methods, systems, and equipment for self-regenerative distillation of ethylene glycol

Abstract

A control method for self-regenerative distillation of ethylene glycol includes the following steps for controlling the concentration of butanediol at the top of an ethylene glycol dealcoholization column: measuring the concentration of butanediol at the top of the column; establishing a butanediol concentration trend prediction model and predicting the butanediol concentration trend; controlling the butanediol concentration; controlling the reflux ratio; controlling the top reflux flow rate based on changes in the butanediol concentration; and controlling the reflux flow rate regulating valve.

Description

Technical Field

[0001] This invention relates to the field of computer control, and in particular to a control method, system, and equipment for self-regenerative distillation of ethylene glycol. Background Technology

[0002] Ethylene glycol, also known as glycol, is an important basic organic raw material in the petrochemical industry. It is mainly used in the production of polyester fibers (polyester), polyester films, polyester engineering plastics, and antifreeze. It is also used in the production of lubricants, plasticizers, hydraulic braking fluids, nonionic surfactants, glycol ethers, explosives, coatings, and inks, among other applications. Globally, polyester products (including polyester, packaging resins, polyester films, and others) account for approximately 90% of ethylene glycol consumption. In my country, over 74% of ethylene glycol is used in the production of polyester fibers such as polyester. Summary of the Invention

[0003] One of the objectives of this invention is to provide a control method, system, and equipment for self-regenerating ethylene glycol distillation, which can significantly reduce the consumption of steam and circulating water in the distillation column after upgrading the grade and calorific value, improve the automation level and operational stability of the equipment, and increase economic benefits.

[0004] One of the objectives of this invention is to provide a control method, system, and equipment for self-regenerating ethylene glycol distillation. By using big data and artificial intelligence methods, supplemented by model predictive control (MPC), industrial mechanism models, and other technologies, the self-regenerating ethylene glycol distillation is controlled, and the operating parameters of the distillation column are optimized in real time to ensure that it operates in the optimal state under different operating conditions, thereby achieving the goal of energy saving.

[0005] To achieve at least one objective of this invention, the present invention provides a method for controlling the self-regenerative distillation of ethylene glycol, the method comprising the following steps for controlling the concentration of butanediol at the top of the ethylene glycol dealcoholization column:

[0006] Perform the measurement of butanediol concentration at the top of the ethylene glycol dealcoholization column;

[0007] Establish a butanediol concentration trend prediction model and perform butanediol concentration trend prediction.

[0008] Control the concentration of butanediol;

[0009] Perform reflux ratio control;

[0010] Based on changes in the butanediol concentration at the top of the column, control the top reflux flow rate; and

[0011] Control the reflux flow regulating valve.

[0012] In some embodiments, the control method for self-regenerating ethylene glycol distillation further includes the following steps for controlling the ethylene glycol concentration in the bottom of the ethylene glycol dealcoholization column: establishing a measurement model for the ethylene glycol concentration in the bottom of the column and measuring the ethylene glycol concentration in the bottom of the ethylene glycol dealcoholization column; establishing a butanediol concentration trend prediction model and predicting the butanediol concentration trend; performing online correction of the ethylene glycol concentration; controlling the ethylene glycol concentration based on the butanediol column flow feedforward; controlling the sensitive plate temperature based on the corrected sensitive plate temperature; controlling the reboiler feed rate; and performing compressor frequency conversion regulation to control the bottom temperature.

[0013] In some embodiments, the control method for self-regenerating ethylene glycol distillation further includes the following steps: constructing an experience database module, acquiring historical operating data of the butanediol removal column, updating the experience database module; and acquiring changes in feed parameters, and outputting recommended values ​​of optimal operating parameters under the current operating conditions based on the current operating conditions.

[0014] In some embodiments, a compressor frequency regulation model is established; based on the ethylene glycol concentration in the bottom of the column, the operating frequency of the compressor is adjusted within a preset optimized frequency range to regulate the ethylene glycol concentration.

[0015] In some embodiments, the concentration of ethylene glycol in the bottom of the butanediol removal column is controlled by temperature control of a sensitive plate and liquid level control of the bottom column.

[0016] In some embodiments, the identification, prediction, and control of each model are constructed using matrix equations.

[0017] According to another aspect of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, performs the steps of the control method for the self-regenerative distillation of ethylene glycol.

[0018] According to another aspect of the present invention, a control device for self-regenerative distillation of ethylene glycol is also provided, comprising:

[0019] Memory, used to store software applications.

[0020] A processor is configured to execute the software application, wherein each program of the software application correspondingly executes a step of the control method for the self-regenerative distillation of ethylene glycol.

[0021] According to another aspect of the present invention, a control system for self-regenerative distillation of ethylene glycol is also provided. The control system includes a dynamic matrix control unit, comprising a data acquisition module, a prediction module, a linear programming module, a dynamic control calculation module, and a setpoint output module. The data acquisition module collects real-time data from a DCS or database at preset intervals to acquire and transmit the predicted value of the controlled variable from the previous cycle, the operated value of the controlled variable, the current value of the operated variable, and the current value of the feedforward variable. The prediction module performs prediction. The linear programming module performs linear programming, and the dynamic control calculation module performs dynamic control calculation. After the prediction module performs prediction, the linear programming module performs linear programming, and the dynamic control calculation module performs dynamic control calculation, the setpoint output module outputs new setpoints for the operating variables to the DCS or database. The operating variables include the top product valve, the top reflux valve, the bottom product valve, the bottom heating valve, and the compressor frequency converter. The controlled variables include the top temperature, the purity of the top product, the bottom temperature, and the bottom liquid level. The feedforward variables include the feed flow rate, the feed temperature, and the feed composition.

[0022] In some embodiments, the dynamic matrix control unit further includes a prediction result correction module and a measured value control module. The prediction result correction module predicts future changes of the device based on the input value and the internal model, and compares the predicted value of the previous period with the current actual value. The deviation between the two is used to correct the prediction result. When the measured value exceeds the preset limit range of the controlled variable, the measured value control module controls the measured value within the limit range of the controlled variable. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the steps for controlling the butanediol concentration at the top of an ethylene glycol dealcoholization column in a control method for ethylene glycol self-regenerative distillation according to an embodiment of the present invention.

[0024] Figure 2 This is a flowchart of the steps for controlling the ethylene glycol concentration in the bottom of the ethylene glycol dealcoholization column in the control method of ethylene glycol self-regenerative distillation according to the above embodiments of the present invention.

[0025] Figure 3 This is a schematic diagram of a control system for self-regenerative distillation of ethylene glycol according to an embodiment of the present invention.

[0026] Figure 4 This is a process flow diagram of the ethylene glycol removal tower in the control system of the self-regenerative distillation of ethylene glycol according to the above embodiments of the present invention. Detailed Implementation

[0027] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0028] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0029] The ethylene glycol distillation unit involved in this invention comprises five columns. The first and second columns primarily separate methanol, a hydrogenation product. The third column produces light components such as methyl glycolate and ethanol at its top. The fourth column (butanediol removal column) removes butanediol and other trace esters. Crude ethylene glycol from the bottom of the column enters the fifth column, which yields ethylene glycol at its top and contains light and heavy components including alcohols at its bottom. The fourth column (butanediol removal column) has a relatively small temperature difference between its top and bottom, allowing the latent heat of condensation of the gas at its top to generate low-pressure steam. This low-pressure steam is then heated and pressurized by a heat pump and used as a heat source for the reboiler at the bottom of the column.

[0030] The goal of ethylene glycol self-regenerative distillation control is to reduce the total energy consumption of ethylene glycol distillation. The operating variables involved in this invention include the top outlet valve, top reflux valve, bottom outlet valve, bottom heating valve, and compressor frequency converter. The controlled variables include top temperature, top product purity, bottom temperature, and bottom liquid level. The feedforward variables include feed flow rate, feed temperature, and feed composition. By modeling the operating and controlled variables under different feedforward variable scenarios, the constraints between them are obtained. Then, AI data mining is performed to obtain the optimal operating values ​​of the operating variables under different scenarios.

[0031] This invention relates to computer programs. For example... Figure 1 and Figure 2The diagram shows a flowchart of a control method for self-regenerative ethylene glycol distillation based on the present invention. It illustrates a solution to the problems proposed in this invention, based on a computer program processing flow. The solution involves executing a computer program compiled according to the above flow to control or process external or internal objects of the computer. Through the control method for self-regenerative ethylene glycol distillation of the present invention, a computer system can be used to control the concentration of butanediol at the top of the ethylene glycol dealcoholization column and the concentration of ethylene glycol at the bottom of the column. By using big data and artificial intelligence methods, supplemented by model predictive control (MPC), industrial mechanism models, and other technologies, the self-regenerative ethylene glycol distillation is controlled, and the operating parameters of the distillation column are optimized in real time, ensuring optimal operation under different conditions. This achieves energy saving, significantly reduces the consumption of steam and circulating water in the distillation column after upgrading the grade and calorific value, improves the automation level and operational stability of the unit, and increases economic efficiency. It is understood that the term "computer" in this invention refers not only to desktop computers, laptops, tablets, etc., but also to other intelligent electronic devices capable of running programs and processing data.

[0032] Specifically, such as Figure 1 As shown, the control method for the self-regenerative distillation of ethylene glycol includes the following steps for controlling the concentration of butanediol at the top of the ethylene glycol dealcoholization column:

[0033] Perform the measurement of butanediol concentration at the top of the ethylene glycol dealcoholization column;

[0034] Establish a butanediol concentration trend prediction model and perform butanediol concentration trend prediction.

[0035] Control the concentration of butanediol;

[0036] Perform reflux ratio control;

[0037] Based on changes in the butanediol concentration at the top of the column, control the top reflux flow rate; and

[0038] Control the reflux flow regulating valve.

[0039] Specifically, in the butanediol concentration trend prediction model, the butanediol content in the top product is predicted by using the top reflux flow rate, top temperature, sensitive plate temperature, circulating water flow rate, and top pressure as variables, and real-time correction is performed.

[0040] By controlling the butanediol concentration at the top of the ethylene glycol dealcoholization tower, stable product quality and "edge-limit" control of product quality can be achieved.

[0041] Furthermore, the control method for the self-regenerative distillation of ethylene glycol includes the following steps for controlling the ethylene glycol concentration in the bottom of the ethylene glycol dealcoholization column:

[0042] Establish a measurement model for the ethylene glycol concentration in the bottom of the ethylene glycol dehydration column, and perform the measurement of the ethylene glycol concentration in the bottom of the ethylene glycol dehydration column;

[0043] Establish a butanediol concentration trend prediction model and perform butanediol concentration trend prediction.

[0044] Perform online calibration of ethylene glycol concentration;

[0045] Based on the butanediol column flow rate feedforward, the ethylene glycol concentration is controlled.

[0046] Control the temperature of the sensitive plate based on the calibrated temperature of the sensitive plate;

[0047] Control of the reboiler feed rate; and

[0048] The compressor frequency converter is used to control the temperature of the tower bottom.

[0049] Furthermore, the control method for the self-regenerative distillation of ethylene glycol also includes the following steps: a bottom liquid level controller controls the liquid level; a bottom circulation flow controller controls the circulation flow; and a bottom circulation flow regulating valve regulates the circulation flow.

[0050] In other words, the ethylene glycol concentration in the bottom of the butanediol removal column is mainly controlled through sensitive plate temperature control and bottom liquid level control. A measurement model for the bottom ethylene glycol concentration is established to predict its real-time performance. Based on process simulation and analysis of key influencing factors, sensitive plate temperature, bottom pressure, feed rate, and bottom output rate are used as key variables to predict the trend of ethylene glycol concentration changes in the bottom, and real-time corrections are made. The bottom temperature is controlled by adjusting the compressor frequency converter based on the ethylene glycol concentration, thereby achieving efficient temperature operation of the system.

[0051] It is worth mentioning that the control method for self-regenerative distillation of ethylene glycol described in this invention constructs a controller model using matrix equations. These matrix equations are applied to the three stages of model identification, prediction, and control during the development and use of the controller. Every 60 seconds, real-time data is collected from the DCS or database to collect and transmit the predicted value of the controlled variable from the previous cycle, the operated value of the controlled variable, the current value of the operated variable, and the current value of the feedforward variable. After completing the three steps of prediction, linear programming, and dynamic control calculation, a new setpoint for the operated variable is output to the DCS. The controller predicts future changes in the device based on the input value and internal model, and compares the predicted value from the previous cycle with the current actual value; the deviation is used to correct the prediction result. This ensures that the predicted value is corrected in each cycle and provides feedback information to the controller. The controller determines the impact of changes in the operated variable and feedforward variable on the controlled variable and corrects the predicted value. When the measured value exceeds the limit range of the controlled variable, the corresponding operated variable will adjust to control the measured value within the limit range of the controlled variable.

[0052] Furthermore, the control method for self-regenerative distillation of ethylene glycol also includes the following steps: constructing an experience database module, acquiring historical operating data of the butanediol removal tower, and updating the experience database module; and acquiring changes in feed parameters and outputting recommended values ​​for optimal operating parameters based on the current operating conditions.

[0053] Furthermore, the control method for the self-regenerative distillation of ethylene glycol also includes the following steps: real-time acquisition of historical data from the butanediol removal tower, prediction, linear programming and control calculation of the control variables, outputting new set values ​​to the DCS; and obtaining the preset range of the controlled variable and performing adjustment.

[0054] Furthermore, the control method for the self-regenerative distillation of ethylene glycol also includes the following steps: establishing a control parameter optimization model, obtaining the current operating conditions and control effects, and optimizing the control model parameters and related thresholds in real time to enable the control model to adapt to the control conditions. This step enhances the robustness of the model, and by continuously optimizing the control range thresholds, the control effect becomes more stable.

[0055] Furthermore, the control method for self-regenerative distillation of ethylene glycol also includes the following steps: establishing a compressor frequency regulation model; based on the ethylene glycol concentration in the bottom of the column and the control model designed according to the AI ​​coupled model predictive control method, adjusting the operating frequency of the compressor within a preset optimized frequency range to finely regulate the ethylene glycol concentration.

[0056] Those skilled in the art will understand that embodiments of the present invention can be provided in the form of methods, systems, or computer program products. Therefore, the present invention can take the form of an all-hardware embodiment, an all-software embodiment, or an embodiment combining software and hardware.

[0057] Those skilled in the art will understand that the method of the present invention can be implemented by hardware, software, or a combination of both. The present invention can be implemented centrally in at least one computer system, or distributed in a decentralized manner by different parts distributed across several interconnected computer systems. Any computer system or other device capable of implementing the method is applicable. A common combination of hardware and software can be a general-purpose computer system with computer programs installed, controlling the computer system to operate according to the method by installing and executing the programs.

[0058] This invention can be embedded in a computer program product, which includes all the features that enable the methods described herein to be implemented. The computer program product is contained in one or more computer-readable storage media having computer-readable program code contained therein. According to another aspect of the invention, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, is capable of performing the steps of the methods of the invention. A computer storage medium is a medium in a computer memory used to store some discontinuous physical quantity. Computer storage media include, but are not limited to, semiconductors, disk drives, magnetic cores, magnetic drums, magnetic tapes, laser disks, etc. Those skilled in the art will understand that computer storage media are not limited to the foregoing examples, which are merely illustrative and not intended to limit the invention.

[0059] According to another aspect of the present invention, a control device for self-regenerative distillation of ethylene glycol is also provided. This control device includes: a software application program, a memory for storing the software application program, and a processor for executing the software application program. Each program in the software application program is capable of correspondingly executing the steps in the control method for self-regenerative distillation of ethylene glycol according to the present invention.

[0060] Those skilled in the art will understand that the device can be embodied in a desktop computer, laptop, mobile smart device, etc., but the foregoing is merely an example and also includes other smart control devices equipped with the software application of the present invention.

[0061] Corresponding to the embodiments of the method of the present invention, according to another aspect of the present invention, a control system for self-regenerative distillation of ethylene glycol is also provided. This control system is an application of the control method for self-regenerative distillation of ethylene glycol of the present invention in terms of computer program improvement.

[0062] Specifically, in Figure 3 and Figure 4In the specific embodiment shown, in the control system for the self-regenerative distillation of ethylene glycol, all on-site data is acquired by the PLC. The PLC then communicates with the algorithm server, and the control commands output by the algorithm are used by the PLC to control the actuators. Simultaneously, a host computer is configured in the office at the equipment site to facilitate operators monitoring the equipment's operating status, and a remote management station is configured in the cloud to remotely iterate and upgrade the algorithms and related software on the algorithm server.

[0063] Specifically, in one embodiment, the control system for the self-regenerative distillation of ethylene glycol includes a DMC controller. The DMC uses matrix equations to describe the controller model, which are applied to the three stages of model identification, prediction, and control during the controller's development and use. Every 60 seconds, the DMC controller collects real-time data from the DCS or database, performing data acquisition and transmission of the predicted value of the controlled variable from the previous cycle, the operated value of the controlled variable, the current value of the operated variable, and the current value of the feedforward variable. After completing the three steps of prediction, linear programming, and dynamic control calculation, it outputs a new setpoint for the operated variable to the DCS. The controller predicts future changes in the device based on the input value and internal model, and compares the predicted value from the previous cycle with the current actual value; the deviation is used to correct the prediction result. This ensures that the predicted value is corrected in each cycle and provides feedback information to the controller. The controller determines the impact of changes in the operated variable and feedforward variable on the controlled variable and corrects the predicted value. When the measured value exceeds the limit range of the controlled variable, the corresponding operated variable will adjust to control the measured value within the limit range of the controlled variable.

[0064] Specifically, in one embodiment, the control system for the self-regenerative distillation of ethylene glycol includes a dynamic matrix control unit. This dynamic matrix control unit comprises a data acquisition module, a prediction module, a linear programming module, a dynamic control calculation module, a setpoint output module, a prediction result correction module, an information feedback module, and a measured value control module. Specifically, the data acquisition module collects real-time data from the DCS or database every preset time interval, such as 60 seconds, to collect and transmit the predicted value of the controlled variable from the previous cycle, the operated value of the controlled variable, the current value of the operated variable, and the current value of the feedforward variable. The prediction module performs prediction, the linear programming module performs linear programming, and the dynamic control calculation module performs dynamic control calculation. After the prediction module performs prediction, the linear programming module performs linear programming, and the dynamic control calculation module performs dynamic control calculation, the setpoint output module outputs a new setpoint value for the operated variable to the DCS or database. The prediction result correction module predicts future changes in the device based on the input value and internal model, and compares the predicted value from the previous cycle with the current actual value; the deviation between the two is used to correct the prediction result. After the prediction result correction module corrects the predicted value at each cycle, the information feedback module provides feedback information. The prediction result correction module determines the impact of changes in the manipulated variable and feedforward variable on the controlled variable and corrects the predicted value. When the measured value exceeds the limit range of the controlled variable, the corresponding manipulated variable will adjust accordingly, and the measured value control module will control the measured value within the limit range of the controlled variable.

[0065] Furthermore, when controlling the butanediol concentration at the top of the ethylene glycol self-regenerative distillation control system, the dynamic matrix control unit predicts the butanediol content in the top product based on process simulation and correlation analysis of key influencing factors, using top reflux flow rate, top temperature, sensitive plate temperature, circulating water flow rate, and top pressure as key variables, and performs real-time corrections. The top reflux flow rate is adjusted according to changes in the top butanediol concentration, achieving stable product quality and near-critical quality control.

[0066] The control system for the self-regenerative distillation of ethylene glycol includes a butanediol concentration control unit at the top of the column. This unit comprises a butanediol concentration measurement module, a butanediol concentration trend prediction module, a butanediol concentration control module, a reflux ratio control module, a reflux flow rate control module, and a reflux flow rate regulating valve control module. The butanediol concentration measurement module measures the butanediol concentration at the top of the ethylene glycol dealcosinate column. The butanediol concentration trend prediction module establishes a butanediol concentration trend prediction model and predicts the butanediol concentration trend. The butanediol concentration control module controls the butanediol concentration. The reflux ratio control module controls the reflux ratio. The reflux flow rate control module controls the reflux flow rate based on changes in the top butanediol concentration. The reflux flow rate regulating valve control module controls the reflux flow rate regulating valve.

[0067] Furthermore, in the control system of the ethylene glycol self-regenerative distillation, the dynamic matrix control unit, when controlling the ethylene glycol concentration in the bottom of the ethylene glycol-butanediol removal column, primarily achieves concentration regulation through sensitive plate temperature control and bottom liquid level control. By establishing a measurement model for the bottom ethylene glycol concentration, real-time prediction of the concentration is made. Based on process simulation and analysis of key influencing factors, the changing trend of the bottom ethylene glycol concentration is predicted using sensitive plate temperature, bottom pressure, feed rate, and bottom output rate as key variables, and real-time corrections are performed. The bottom temperature is controlled by adjusting the compressor frequency converter based on the bottom ethylene glycol concentration, achieving efficient temperature operation of the system.

[0068] The control system for the self-regenerative distillation of ethylene glycol includes a bottom ethylene glycol concentration control unit. This unit comprises an ethylene glycol concentration measurement model module, a butanediol concentration trend prediction model, an ethylene glycol concentration online correction module, an ethylene glycol concentration control execution module, a sensitive plate temperature control module, a reboiler feed rate control module, and a compressor frequency converter module. The ethylene glycol concentration measurement model module establishes a model for measuring the ethylene glycol concentration in the bottom of the ethylene glycol dehydration column and performs the measurement of the ethylene glycol concentration. The butanediol concentration trend prediction model establishes a model for predicting the butanediol concentration trend and performs the prediction of the butanediol concentration trend. The online ethylene glycol concentration correction module performs online correction of the ethylene glycol concentration. The ethylene glycol concentration control execution module controls the ethylene glycol concentration based on the butanediol column flow rate feedforward. The sensitive plate temperature control module controls the sensitive plate temperature based on the corrected sensitive plate temperature. The reboiler feed rate control module controls the reboiler feed rate. Finally, the compressor frequency converter module performs compressor frequency conversion regulation to control the bottom temperature.

[0069] Furthermore, in a specific embodiment, the control system for the self-regenerative distillation of ethylene glycol also includes an empirical database model module, a predictive operating trend and dynamic control module, a control parameter optimization model, and a compressor frequency adjustment model module. The empirical database model module continuously maintains the empirical database based on historical operating data of the butanediol removal tower, creating an "expert system" that can output recommended optimal operating parameters based on the current operating conditions when feed parameters change. The predictive operating trend and dynamic control module collects historical data from the butanediol removal tower in real time, performs prediction, linear programming, and control calculations on the control variables, and then outputs new setpoints to the DCS. Operators only need to set the controlled variables within an appropriate range, and the controller will automatically adjust. The control parameter optimization model optimizes the control model parameters and related thresholds in real time based on the current operating conditions and control effects, enabling the control model to adapt to the control conditions, enhancing the model's robustness, and making the control effect more stable through continuous optimization of the control range thresholds. The compressor frequency regulation model module adjusts the compressor's operating frequency within an optimized frequency range based on the ethylene glycol concentration in the tower bottom and a control model designed using an AI-coupled model predictive control method, thereby finely controlling the ethylene glycol concentration.

[0070] Those skilled in the art will understand that the invention has been described with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products according to the invention. Each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can obviously be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, thereby instructing (the instructions via the processor of the computer or other programmable data processing apparatus) to generate means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or block diagrams.

[0071] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and any modifications or variations of the embodiments of the present invention may be made without departing from these principles.

Claims

1. A method for controlling the self-regenerative distillation of ethylene glycol, characterized in that, The control method for the self-regenerative distillation of ethylene glycol includes the following steps for controlling the concentration of butanediol at the top of the ethylene glycol dealcoholization column: Perform the measurement of butanediol concentration at the top of the ethylene glycol dealcoholization column; Establish a butanediol concentration trend prediction model and perform butanediol concentration trend prediction. Control the concentration of butanediol; Perform reflux ratio control; Based on the change in butanediol concentration at the top of the column, the reflux flow rate at the top of the column is controlled. as well as Control the reflux flow regulating valve; The control method for the self-regenerative distillation of ethylene glycol further includes the following steps for controlling the ethylene glycol concentration in the bottom of the ethylene glycol dealcoholization column: establishing a measurement model for the ethylene glycol concentration in the bottom of the column and measuring the ethylene glycol concentration in the bottom of the ethylene glycol dealcoholization column; establishing a butanediol concentration trend prediction model and predicting the butanediol concentration trend; performing online correction of the ethylene glycol concentration; controlling the ethylene glycol concentration based on the butanediol column flow feedforward; controlling the sensitive plate temperature based on the corrected sensitive plate temperature; controlling the reboiler feed rate; and controlling the column bottom temperature by performing compressor frequency conversion regulation. The control method for the self-regenerative distillation of ethylene glycol further includes the following steps: a bottom liquid level controller controls the liquid level; a bottom circulation flow controller controls the circulation flow; and a bottom circulation flow regulating valve regulates the circulation flow. The controller model is constructed using matrix equations, which are applied to the model identification, prediction, and control stages of the controller's development and use. Every 60 seconds, real-time data is collected from the DCS or database to collect and transmit the predicted value of the controlled variable from the previous cycle, the operated value of the controlled variable, the current value of the operated variable, and the current value of the feedforward variable. After performing prediction, linear programming, and dynamic control calculations, the new setpoint value of the operated variable is output to the DCS. The controller predicts future changes in the device based on the input value and internal model, and compares the predicted value from the previous cycle with the current actual value. The deviation between the two is used to correct the prediction result, thus correcting the predicted value in each cycle and providing feedback information to the controller. The controller determines the impact of changes in the operated variable and feedforward variable on the controlled variable and corrects the predicted value. When the measured value exceeds the limit range of the controlled variable, the corresponding operated variable performs an adjustment action to control the measured value within the preset limit range of the controlled variable.

2. The control method for self-regenerative distillation of ethylene glycol as described in claim 1, wherein the control method for self-regenerative distillation of ethylene glycol further includes the following steps: An experience database module is constructed to obtain historical operating data of the butanediol removal tower and update the experience database module; and changes in feed parameters are obtained, and the recommended values ​​of the best operating parameters under the current operating conditions are output based on the current operating conditions.

3. The control method for self-regenerative distillation of ethylene glycol as described in claim 1, wherein a compressor frequency regulation model is established; based on the ethylene glycol concentration in the bottom of the column and the control model designed according to the AI ​​coupled model predictive control method, the operating frequency of the compressor is adjusted within a preset optimized frequency range to regulate the ethylene glycol concentration.

4. The control method for self-regenerative distillation of ethylene glycol as described in claim 3, wherein the concentration of ethylene glycol in the bottom of the butanediol removal column is controlled by temperature control of a sensitive plate and liquid level control of the bottom column.

5. The control method for self-regenerative distillation of ethylene glycol as described in claim 1, wherein the identification, prediction, and control of each model are constructed through matrix equations.

6. The control method for self-regenerative distillation of ethylene glycol as described in any one of claims 1 to 5, wherein, The control method for self-regenerative distillation of ethylene glycol is applied to the control system of self-regenerative distillation of ethylene glycol. The control system is equipped with a dynamic matrix control unit, which includes a data acquisition module, a prediction module, a linear programming module, a dynamic control calculation module, and a setpoint output module. The data acquisition module collects real-time data from the DCS or database at preset intervals, performing data acquisition and transmission of the predicted value of the controlled variable from the previous cycle, the operated value of the controlled variable, the current value of the operated variable, and the current value of the feedforward variable. The prediction module performs prediction. The linear programming module performs linear programming, and the dynamic control calculation module performs dynamic control calculation. After the prediction module performs prediction, the linear programming module performs linear programming, and the dynamic control calculation module performs dynamic control calculation, the setpoint output module outputs new setpoints for the operating variables to the DCS or database. The operating variables include the top product valve, the top reflux valve, the bottom product valve, the bottom heating valve, and the compressor frequency converter. The controlled variables include the top temperature, the purity of the top product, the bottom temperature, and the bottom liquid level. The feedforward variables include the feed flow rate, the feed temperature, and the feed composition.

7. The control method for self-regenerative distillation of ethylene glycol as described in claim 6, wherein the dynamic matrix control unit further includes a prediction result correction module and a measured value control module, wherein the prediction result correction module predicts future changes of the device based on the input value and the internal model, and compares the predicted value of the previous period with the current actual value, and the deviation between the two is used to correct the prediction result; when the measured value exceeds the preset limit range of the controlled variable, the measured value control module controls the measured value within the limit range of the controlled variable.

Images