Temperature control method, system, device and medium for ptfepolymerization reactor

Abstract

This invention relates to a temperature control method, system, equipment, and medium for a PTFE polymerization reactor. The method includes: performing curve fitting on the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage according to a time series to obtain a temperature change target curve and a feed target curve; using the temperature change target curve and the feed target curve as controlled variables, and the cooling water flow rate of the PTFE polymerization reactor as a manipulated variable, performing multivariate control target prediction to obtain a temperature control scheme fitted to the time series; and modifying the temperature control scheme based on the feed target curve and the acquired cooling water temperature information, so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the modified temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor. This invention solves the technical problems of insufficient timeliness and low adaptability of existing temperature control methods for PTFE polymerization reactors.

Description

Technical Field

[0001] This invention relates to the field of chemical product production process control technology, and in particular to a temperature control method, system, equipment and medium for a PTFE polymerization reactor. Background Technology

[0002] PTFE (polytetrafluoroethylene) polymerization reactors are used to produce PTFE. The control of these reactors involves managing reaction pressure, temperature, rate, time, and quantity to ensure product quality. Reaction temperature directly affects the reaction rate. Since PTFE polymerization is exothermic, the reactor temperature directly impacts the initiator's decomposition rate. Higher temperatures accelerate the reaction rate and generate significant heat. If cooling is not implemented after reaching a certain temperature, explosive polymerization can occur, leading to uncontrolled temperature regulation and substandard products. Furthermore, higher temperatures result in more vigorous polymerization, lower reactor pressure, and a larger TFE monomer feed rate. The monomer feed rate is also influenced by the polymerization rate.

[0003] Currently, in order to ensure the stability of the reaction temperature in the PTFE polymerization reactor, water cooling is usually used. By setting a cold water valve, the cold water valve is opened or closed when the reaction temperature exceeds or falls below a set threshold, so as to control the temperature of the PTFE polymerization reactor through cooling water.

[0004] However, the current temperature control scheme for PTFE polymerization reactors, which simulates manual operation by controlling the opening and closing of cooling water based on temperature changes, lacks a reasonable control target. When the temperature change rate is too rapid, the cooling water is turned on to lower the temperature; when the temperature is about to recover, the cooling water is completely shut off to prevent further temperature drop. Therefore, the existing temperature control scheme for PTFE polymerization reactors has the following main shortcomings: First, because it adjusts solely based on the rate of temperature change, it cannot adapt to all operating conditions. If the reaction is too slow or too fast, it can easily lead to abnormal temperature adjustment. Second, when there is a significant lag in the temperature change during polymerization, the temperature adjustment is not timely enough, and the temperature is prone to recovering. Furthermore, the cooling water valve uses a fully open and fully closed adjustment method, purely simulating manual operation, which cannot meet the requirements for precise control. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a temperature control method, system, equipment and medium for PTFE polymerization reactors, which solves the technical problems of insufficient timeliness and low adaptability of the existing temperature control methods for PTFE polymerization reactors.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, embodiments of the present invention provide a temperature control method for a PTFE polymerization reactor, comprising:

[0010] The temperature control target data of the PTFE polymerization reactor at each reaction stage were obtained and curve-fitted according to the time series to obtain the temperature change target curve and the feed target curve.

[0011] Using the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, a multivariate control target prediction was performed to obtain a temperature control scheme with a fitted time series.

[0012] Based on the target feed curve and the obtained cooling water temperature information, the temperature control scheme is modified so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted according to the modified temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

[0013] Optionally, before performing time-series curve fitting on the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage to obtain the temperature change target curve and the feed target curve, the method further includes:

[0014] Extract the data of the first reaction process with the optimal reaction temperature and the data of the second reaction process with the optimal monomer feed from the pre-set empirical database;

[0015] Based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature, and based on the first reaction process data, the target temperature change curve for each reaction temperature stage is fitted according to the time series.

[0016] Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages for monomer feed rate, and the feed target curve for each feeding stage is fitted according to the time series based on the second reaction process data.

[0017] Optionally, based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature, and based on the first reaction process data, a target temperature change curve for each reaction temperature stage is fitted according to a time series, including:

[0018] Based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature, resulting in reaction temperature stages including the initial stage, transition stage, violent stage, and stable stage.

[0019] When the reaction temperature stage is the initial stage, the actual temperature data of the PTFE polymerization reactor is fitted to the first temperature change target curve according to the time series.

[0020] When the reaction temperature stage is the transition stage, the temperature control target data of the transition stage is fitted into the second temperature change target curve according to the time series.

[0021] When the reaction temperature stage is the intense stage, the temperature control target data of the intense stage is fitted into the third temperature change target curve according to the time series.

[0022] When the reaction temperature is in a stable phase, the temperature control target data of the stable phase is fitted into a fourth temperature change target curve according to the time series.

[0023] Based on the inflection point of temperature change, the first temperature change target curve, the second temperature change target curve, the third temperature change target curve, and the fourth temperature change target curve are sequentially connected to obtain the temperature change target curve of the PTFE polymerization reactor.

[0024] Optionally, based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages for monomer feed rate, and based on the second reaction process data, a feed target curve for each feed stage is fitted according to the time series, including:

[0025] Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of monomer feed rate to obtain the feed stages including the initial stage, the rising stage and the steady stage.

[0026] When the feeding stage is the initial stage, the actual feeding data of the PTFE polymerization reactor is fitted to the first feeding target curve according to the time series.

[0027] When the feeding stage is the rising stage, the feeding control target data of the rising stage is fitted into the second feeding target curve according to the time series;

[0028] When the feeding stage is in a stable stage, the feeding control target data of the stable stage is fitted into the third feeding target curve according to the time series;

[0029] Based on the inflection point of the feed change, the first feed change target curve, the second feed change target curve, and the third feed change target curve are sequentially connected to obtain the feed change target curve of the PTFE polymerization reactor.

[0030] Optionally, using the target temperature change curve and the target feed curve as the controlled variables, and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, a multivariate control target prediction is performed to obtain a temperature control scheme that fits the time series, including:

[0031] Based on the extreme values ​​of cooling water flow rate in the PTFE polymerization reactor, the temperature control constraints of the PTFE polymerization reactor are obtained.

[0032] Based on the temperature control constraints, a multivariate predictive control model is established with the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable.

[0033] Based on the time series, a temperature control scheme that fits the time series is obtained through a multivariate predictive control model. This temperature control scheme is the cooling water flow rate data curve fitted according to the time series.

[0034] The mathematical expression for the multivariate predictive control model is as follows:

[0035]

[0036] In the formula, u(i) represents the operated variable, x(i) and y(i) represent the controlled variable, n represents the time node, and x ref (i) represents the reference trajectory of the controlled variable x(i) in each period, y ref (i) represents the reference trajectory of the controlled variable y(i) in each period, Q represents the weight matrix of the controlled variable x(i), R represents the weight matrix of the controlled variable y(i), f represents the dynamic equation of the control prediction model, and u(i) max This represents the upper limit of the operand, x(i). min This represents the lower bound of the target value for the operation variable x(i). max Let y(i) represent the target upper bound of the operation variable x(i). min This represents the lower bound of the target value for the operation variable y(i). max This represents the target upper limit of the operation variable y(i).

[0037] Optionally, based on the target feed curve and the obtained cooling water temperature information, the temperature control scheme is modified so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the modified temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor, including:

[0038] Obtain the temperature information of the cooling water in the PTFE polymerization reactor;

[0039] Based on the feed target curve and cooling water temperature information, the cooling water demand is obtained. This cooling water demand is an intermediate parameter used to correct the temperature control scheme, obtained by processing the reaction temperature and cooling water temperature using the law of conservation of heat.

[0040] Based on the cooling water demand, the multivariate predictive control model of the predicted temperature control scheme is modified, and the temperature change target curve and the feed target curve are input into the modified multivariate predictive control model for calculation to obtain the optimal temperature control scheme for the PTFE polymerization reactor.

[0041] The mathematical expression for the modified multivariate predictive control model is as follows:

[0042]

[0043] In the formula, u*(i) represents the optimal manipulated variable, Δu(i) represents the increment of the manipulated variable, and S represents the weight matrix of the increment in the manipulated variable. min Δu(i) represents the lower bound of the increment of the operated variable. max This represents the upper limit of the increment of the operated variable.

[0044] Optionally, based on the feed target curve and cooling water temperature information, the cooling water demand is obtained. This cooling water demand is an intermediate parameter used to correct the temperature control scheme, obtained by processing the reaction temperature and cooling water temperature using the law of conservation of heat.

[0045] Based on the feed target curve, obtain the heat released in the PTFE polymerization reactor at each reaction stage;

[0046] The heat absorbed by the cooling water is obtained based on the temperature difference data of the inlet and outlet of the PTFE polymerization reactor.

[0047] Based on the heat released and absorbed, and combined with the water demand calculation formula, the cooling water demand of the PTFE polymerization reactor is obtained;

[0048] The formula for calculating water demand is as follows:

[0049]

[0050] In the formula, H represents the cooling water demand, C represents the specific heat capacity, F2 represents the cooling water flow rate, Δt represents the cumulative time, ΔT is the temperature difference between the cooling water inlet and outlet, F1 represents the single-unit feed rate, and K represents the proposed heat release energy.

[0051] Secondly, embodiments of the present invention provide a temperature control system for a PTFE polymerization reactor, comprising:

[0052] The target curve acquisition module is used to perform curve fitting on the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage according to the time series to obtain the temperature change target curve and the feed target curve.

[0053] The control prediction module is used to perform multivariate control target prediction with the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, so as to obtain a temperature control scheme with a fitted time series.

[0054] The control scheme correction module is used to correct the temperature control scheme based on the feed target curve and the obtained cooling water temperature information, so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

[0055] Thirdly, embodiments of the present invention provide a PTFE polymerization reaction apparatus, comprising:

[0056] PTFE polymerization reactor;

[0057] A temperature sensor is installed inside the PTFE polymerization reactor.

[0058] A feed flow meter is installed on the feed pipe of the PTFE polymerization reactor;

[0059] The cooling water valve is installed on the cooling water inlet pipe of the PTFE polymerization reactor;

[0060] The controller is connected to the temperature sensor, the feed flow meter, and the cooling water valve, respectively, and is used to execute the temperature control method steps of the PTFE polymerization reactor described above.

[0061] Fourthly, embodiments of the present invention provide a computer-readable medium storing computer-executable instructions thereon, which, when executed by a processor, implement the temperature control method steps of the PTFE polymerization reactor described above.

[0062] (III) Beneficial Effects

[0063] The beneficial effects of this invention are as follows: The temperature control method for the PTFE polymerization reactor of this invention employs both a fitted temperature change target curve and a feed target curve as dual control targets. It seeks the optimal solution for cooling water adjustment in the PTFE polymerization reactor through multivariate predictive control, and then corrects this optimal solution using cooling water temperature information, ultimately obtaining a cooling water flow control scheme based on a fitted time series. Compared to existing technologies, this invention fits multiple control target curves, ensuring that control adjustments are made within the expected target values. It standardizes temperature control operations, improves control effectiveness, reduces the workload of on-site operators, and consequently reduces the operation frequency of the PTFE polymerization reactor during the reaction process by more than 90%. Simultaneously, the cooling water flow regulation concept proposed in this invention, under the premise of temperature lag adjustment, ensures that the cooling water volume remains within a suitable range, preventing it from exceeding the adjustment range. Attached Figure Description

[0064] Figure 1 A schematic flowchart illustrating a temperature control method for a PTFE polymerization reactor according to an embodiment of the present invention;

[0065] Figure 2 This is a temperature change target curve fitting diagram of a PTFE polymerization reactor provided in an embodiment of the present invention;

[0066] Figure 3 This is a curve fitting diagram of the feed target curve of a PTFE polymerization reactor provided in an embodiment of the present invention;

[0067] Figure 4 A curve fitting diagram of the temperature control scheme for a PTFE polymerization reactor provided in an embodiment of the present invention;

[0068] Figure 5 This is an application effect diagram of the temperature control scheme for a PTFE polymerization reactor provided in an embodiment of the present invention;

[0069] Figure 6 A software model diagram for predicting temperature control in a PTFE polymerization reactor, provided in an embodiment of the present invention;

[0070] Figure 7 This is a schematic diagram of the composition of a PTFE polymerization reaction apparatus provided in an embodiment of the present invention. Detailed Implementation

[0071] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0072] refer to Figure 1As shown in the embodiment of the present invention, a temperature control method for a PTFE polymerization reactor includes: performing curve fitting on the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage according to a time series to obtain a temperature change target curve and a feed target curve; using the temperature change target curve and the feed target curve as controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable to perform multivariate control target prediction to obtain a temperature control scheme fitted to the time series; and modifying the temperature control scheme according to the feed target curve and the acquired cooling water temperature information so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the modified temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

[0073] This embodiment employs both a fitted temperature change target curve and a feed target curve as dual control objectives. It uses multivariate predictive control to seek the optimal solution for cooling water adjustment in the PTFE polymerization reactor, and then refines this optimal solution using cooling water temperature information. Ultimately, it obtains a cooling water flow control scheme based on a fitted time series. Compared to existing technologies, this embodiment fits multiple control target curves, ensuring control adjustments are made within the expected target values. It standardizes temperature control operations, improves control effectiveness, reduces the workload of on-site operators, and consequently reduces the frequency of PTFE polymerization reactor operations by over 90%. Furthermore, the cooling water flow regulation concept proposed in this embodiment, even under the condition of temperature lag adjustment, ensures that the cooling water volume remains within a suitable range, preventing it from exceeding the adjustment range.

[0074] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0075] Specifically, refer to Figure 1 As shown in the figure, an embodiment of the present invention proposes a temperature control method for a PTFE polymerization reactor, which includes:

[0076] S100. The temperature control target data of the PTFE polymerization reactor at each reaction stage is obtained and curve-fitted according to the time series to obtain the temperature change target curve and the feed target curve.

[0077] In the PTFE polymerization process, the reaction temperature not only directly affects the polymerization rate, but also influences the feed rate, thus indirectly affecting the polymerization rate. For example, the higher the reaction temperature, the more vigorous the PTFE polymerization reaction, the lower the pressure inside the reactor, and the larger the monomer feed rate. When too much monomer accumulates in the feed, it will directly affect the polymerization rate and the production efficiency of the product.

[0078] In this embodiment, step S100 includes the following sub-steps S110 to S130:

[0079] S110. Extract the first reaction process data with the optimal reaction temperature and the second reaction process data with the optimal monomer feed from the preset experience database.

[0080] The experience database stores the experience data of operators in temperature stabilization control. The experience data for a period of time (e.g., all experience data within one year) is selected, some abnormal reaction situations are eliminated, and the experience data within this period of time is optimized to obtain the first reaction process data with the optimal reaction temperature and the second reaction process data with the optimal monomer feed.

[0081] S120. Based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature, and based on the first reaction process data, the target temperature change curve for each reaction temperature stage is fitted according to the time series.

[0082] Further, step S120 includes sub-steps S121 to S123:

[0083] S121. Based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into reaction temperature stages to obtain reaction temperature stages including the initial stage, transition stage, violent stage and stable stage.

[0084] Because the heat absorption and release in the PTFE polymerization reaction vary greatly at different reaction stages, the appropriate temperature inflection point is selected based on the operator's experience data to control the cooling water valve to activate in advance. This allows for matching the corresponding control scheme and related parameters for each stage, thereby achieving precise control of the PTFE polymerization reactor temperature.

[0085] S122a. When the reaction temperature stage is the initial stage, the actual temperature data of the PTFE polymerization reactor is fitted into the first temperature change target curve according to the time series.

[0086] In the initial reaction stage, both the monomer feed rate and the temperature inside the PTFE polymerization reactor are relatively low, resulting in limited heat release, sufficient only to ensure the normal progress of the PTFE polymerization reaction. Therefore, cooling water is not required to remove heat from the PTFE polymerization reactor during this initial stage. The initial temperature and reaction time in this stage are mainly affected by the cooling process during the evacuation and replacement of the PTFE polymerization reactor, as well as by the initiator.

[0087] S122b. When the reaction temperature stage is the transition stage, the temperature control target data of the transition stage is fitted into a second temperature change target curve according to the time series.

[0088] When the reaction temperature stage is the transition stage, the polymerization reaction is relatively mild, and the cooling water valve needs to be opened slowly to allow a small amount of cooling water to remove some of the heat. The goal of selecting the initial inflection point of the target curve for this stage is to open the cooling water valve at this initial temperature inflection point, while maintaining the polymerization reaction heat within the set temperature threshold range.

[0089] S122c. When the reaction temperature stage is the intense stage, the temperature control target data of the intense stage is fitted into the third temperature change target curve according to the time series.

[0090] When the reaction temperature is in the intense reaction stage, the polymerization reaction begins to accelerate rapidly at the initial temperature inflection point because the amount of fed monomers has accumulated to a certain level, and the temperature starts to rise. At this time, a large amount of cooling water is needed to remove a significant amount of heat. The termination temperature inflection point of the intense reaction stage is selected by observing the change in the reaction rate. Taking the position of maximum reaction rate as the termination inflection point of the intense reaction stage can eliminate the hysteresis caused by temperature changes, smoothly reduce the cooling water flow rate, and greatly reduce the probability of the operation temperature rebounding due to a sharp drop in the reaction rate.

[0091] S122d When the reaction temperature stage is in a stable stage, the temperature control target data of the stable stage is fitted into the fourth temperature change target curve according to the time series.

[0092] When the reaction temperature is in a stable phase, the reaction rate decreases slowly and the heat released is relatively reduced. Therefore, it is necessary to slowly reduce the cooling water to remove excess heat and allow the temperature to rise slowly. The initial temperature inflection point of this phase is the termination temperature inflection point of the violent phase.

[0093] S123. Based on the inflection point of temperature change, connect the first temperature change target curve, the second temperature change target curve, the third temperature change target curve, and the fourth temperature change target curve in sequence to obtain the temperature change target curve of the PTFE polymerization reactor.

[0094] In one specific embodiment, the termination temperature inflection point of the first temperature change target curve is connected to the initial temperature inflection point of the second temperature change target curve; the termination temperature inflection point of the second temperature change target curve is connected to the initial temperature inflection point of the third temperature change target curve; and the termination temperature inflection point of the third temperature change target curve is connected to the initial temperature inflection point of the fourth temperature change target curve. The final temperature change target curve of the PTFE polymerization reactor is as follows: Figure 2 As shown.

[0095] S130. Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages for monomer feed amount, and based on the second reaction process data, the feed target curve for each feed stage is fitted according to the time series.

[0096] In this embodiment, the timing for monomer feed fitting differs from the reaction temperature because the rate of polymerization is most directly reflected in the monomer feed. Therefore, if the polymerization reaction is too fast or too slow, the target feed curve may not match the actual reaction data well, thus affecting temperature control. In this embodiment, by analyzing the operator's experience data, the feed data after the reaction rate reaches a set threshold is selected for separate timing to obtain the target feed curve. This improves the curve matching degree and thus enhances the temperature control effect.

[0097] Further, step S130 includes sub-steps S131 to S133:

[0098] S131. Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of monomer feed amount to obtain the feed stage including the initial stage, the rising stage and the stable stage.

[0099] S132a. When the feeding stage is the initial stage, the actual feeding data of the PTFE polymerization reactor is fitted into the first feeding target curve according to the time series.

[0100] In the initial feeding stage, the feed monomers are supplied by the upstream unit, and their properties cannot be controlled. The initial reaction temperature is greatly affected by the feed monomers and initiators; therefore, the target feed curve for this stage varies with actual feed data and has no fixed value.

[0101] S132b: When the feeding stage is the rising stage, the feeding control target data of the rising stage is fitted into the second feeding target curve according to the time series.

[0102] When the feed stage is in the rising phase, this is a critical control phase. It's essential to ensure the monomer feed rate does not exceed the set target threshold during this stage. If it does, a large amount of polymerization will occur in this phase, leading to slower reactions in the next stage and affecting the overall reaction time. Furthermore, the initial feed point in the rising phase represents the initial inflection point of the feed target curve.

[0103] S132c. When the feeding stage is a stable stage, the feeding control target data of the stable stage is fitted into the third feeding target curve according to the time series.

[0104] When the feeding stage is a stable stage, the polymerization reaction tends to be stable. In order to ensure that the reaction time is within a certain range, the actual monomer feed should be kept as close as possible to the fitted curve during the control process of this stage to avoid excessive deviation in reaction time that may affect product quality.

[0105] S133. Based on the inflection point of the feed change, the first feed change target curve, the second feed change target curve, and the third feed change target curve are connected sequentially to obtain the feed change target curve of the PTFE polymerization reactor.

[0106] In one specific embodiment, the first feed change target curve is taken as the initial feed flow rate of the PTFE polymerization reactor. The initial feed inflection point of the second feed change target curve is connected to the first feed change target curve, and the final feed inflection point of the second feed change target curve is connected to the third feed change target curve. The final feed change target curve of the PTFE polymerization reactor is as follows: Figure 3 As shown.

[0107] S200: Using the temperature change target curve and the feed target curve as the controlled variables, and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, multivariate control target prediction is performed to obtain a temperature control scheme that fits the time series.

[0108] In this embodiment, step S200 includes the following sub-steps S210 to S230:

[0109] S210. Based on the extreme value of the cooling water flow rate in the PTFE polymerization reactor, obtain the temperature control constraints of the PTFE polymerization reactor.

[0110] S220. Based on the temperature control constraints, a multivariate predictive control model is established with the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable.

[0111] The mathematical expression for the multivariate predictive control model is:

[0112]

[0113] In the formula, u(i) represents the operated variable, x(i) and y(i) represent the controlled variable, n represents the time node, and x ref (i) represents the reference trajectory of the controlled variable x(i) in each period, y ref (i) represents the reference trajectory of the controlled variable y(i) in each period, Q represents the weight matrix of the controlled variable x(i), R represents the weight matrix of the controlled variable y(i), f represents the dynamic equation of the control prediction model, and u(i) max This represents the upper limit of the operand, x(i). min This represents the lower bound of the target value for the operation variable x(i). max Let y(i) represent the target upper bound of the operation variable x(i). min This represents the lower bound of the target value for the operation variable y(i). max This represents the target upper limit of the operation variable y(i).

[0114] S230. Based on the time series, a temperature control scheme that fits the time series is obtained through a multivariate predictive control model. The temperature control scheme is the cooling water flow rate data curve fitted according to the time series.

[0115] S300: Based on the feed target curve and the obtained cooling water temperature information, the temperature control scheme is modified so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the modified temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

[0116] In this embodiment, step S300 includes the following sub-steps S310 to S330:

[0117] S310. Obtain the temperature information of the cooling water in the PTFE polymerization reactor.

[0118] S320. Based on the feed target curve and cooling water temperature information, obtain the cooling water demand. This cooling water demand is an intermediate parameter obtained by processing the reaction temperature and cooling water temperature using the law of conservation of heat, which is used to correct the temperature control scheme.

[0119] Further, step S320 includes the following sub-steps S321 to S323:

[0120] S321. Based on the feed target curve, obtain the heat released by the PTFE polymerization reactor at each reaction stage.

[0121] Since the PTFE polymerization reactor is a single-TFE polymerization reactor, the reaction rate is equal to the monomer feed rate. Therefore, the heat released Q in each reaction stage of the PTFE polymerization reactor is... 放 The calculation formula is:

[0122] Q 放 =F1·Δt·K

[0123] In the formula, F1 represents the monomer feed rate, K represents the intended exothermic energy, and Δt represents the cumulative time.

[0124] S322. Obtain the heat absorbed by the cooling water based on the temperature difference data of the inlet and outlet of the PTFE polymerization reactor.

[0125] Since the heat of reaction in the PTFE polymerization reactor is mainly absorbed by the cooling water, the heat absorbed by the TFE polymerization reactor in each reaction stage is Q. 吸 The calculation formula is:

[0126] Q 吸 =C·F2·Δt·ΔT

[0127] In the formula, C represents specific heat capacity, F2 represents cooling water flow rate, Δt represents cumulative time, and ΔT is the temperature difference between the inlet and outlet of the cooling water.

[0128] S323. Based on the released heat and absorbed heat, and combined with the water demand calculation formula, obtain the cooling water demand of the PTFE polymerization reactor.

[0129] The formula for calculating water demand is:

[0130]

[0131] In the formula, H represents the cooling water requirement.

[0132] S330. Based on the cooling water demand, the multivariate predictive control model of the predicted temperature control scheme is modified, and the temperature change target curve and the feed target curve are input into the modified multivariate predictive control model for calculation to obtain the optimal temperature control scheme for the PTFE polymerization reactor.

[0133] During the commissioning of the temperature control scheme, situations may arise where the temperature and rate are too high or too low, which can easily lead to a short-term low degree of matching with the water demand, affecting temperature control. Therefore, it is necessary to select the deviation values ​​between the actual temperature and rate and the fitted values ​​to correct the temperature control scheme.

[0134] The mathematical expression for the modified multivariate predictive control model is as follows:

[0135]

[0136] In the formula, u*(i) represents the optimal manipulated variable, Δu(i) represents the increment of the manipulated variable, and S represents the weight matrix of the increment in the manipulated variable. minΔu(i) represents the lower bound of the increment of the operated variable. max This represents the upper limit of the increment of the operated variable.

[0137] In one specific embodiment, when controlling the temperature of the PTFE polymerization reactor, firstly, the target control curve of the PTFE polymerization reactor is obtained, such as... Figure 2 and Figure 3 As shown. Then, Figure 2 and Figure 3 The curve data shown is input into the multivariate predictive control model; then, the output of the multivariate predictive control model is subjected to curve fitting according to the time series to obtain the curve data shown. Figure 4 The cooling water demand curve is shown. Finally, a control scheme incorporating the cooling water demand curve is deployed to the controller of the cooling water valve. The controller uses this cooling water demand curve to control the cooling water flow in real time, so that the temperature control effect of the PTFE polymerization reactor is as shown. Figure 5 As shown (the smooth curve represents the predictive control effect, and the undulating curve represents the actual control effect). The corrected model diagram for the temperature control scheme is shown below. Figure 6 As shown, when the real-time water flow rate deviates too much from the fitted flow rate, the valve action is accelerated to reasonably control the water flow within a suitable range, ensuring stable temperature control and preventing temperature rebound.

[0138] Furthermore, this invention also proposes a temperature control system for a PTFE polymerization reactor, comprising:

[0139] The target curve acquisition module is used to perform curve fitting on the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage according to the time series to obtain the temperature change target curve and the feed target curve.

[0140] The control prediction module is used to predict multivariate control targets using the temperature change target curve and the feed target curve as controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, so as to obtain a temperature control scheme that fits the time series.

[0141] The control scheme correction module is used to correct the temperature control scheme based on the feed target curve and the obtained cooling water temperature information, so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

[0142] Also, see reference Figure 7As shown in the figure, this embodiment of the invention also proposes a PTFE polymerization reactor, including: a PTFE polymerization reactor; a temperature sensor installed inside the PTFE polymerization reactor; a feed flow meter installed on the feed pipe of the PTFE polymerization reactor; a cooling water valve installed on the cooling water inlet pipe of the PTFE polymerization reactor; and a controller connected to the temperature sensor, the feed flow meter, and the cooling water valve, respectively, for executing the temperature control method steps of the PTFE polymerization reactor described above.

[0143] In this embodiment, as Figure 7 As shown, pure water and initiator are added to the PTFE polymerization reactor in sequence. After leak testing, the agitator inside the reactor is turned on, and oxygen is removed by evacuation and nitrogen purging. Once the oxygen content is within acceptable limits, TFE monomer is added. After pressurization, the TFE monomer enters the polymerization reaction stage. During the reaction, the reactor pressure must be maintained constant, and the reactor temperature is kept to rise steadily by adjusting the cooling water flow rate. The temperature should not show a downward trend during the reaction, and it should not exceed the set value at the end of the reaction. After the reaction is complete, the polymerized PTFE product is discharged to the subsequent washing and drying process. Finally, the reactor is cleaned to prepare for the next batch of production.

[0144] Finally, this embodiment of the invention also proposes a computer-readable medium storing computer-executable instructions, which, when executed by a processor, implement the temperature control method steps of the PTFE polymerization reactor described above.

[0145] In summary, this invention provides a temperature control method, system, equipment, and medium for a PTFE polymerization reactor. Based on process analysis of the PTFE polymerization reaction, this invention establishes a control model for cooling water in relation to reaction temperature and rate. A controller then executes reaction temperature control to find the optimal solution for cooling water adjustment. Simultaneously, based on the principle of heat balance, the cooling water demand is continuously calculated, providing a new benchmark value for the controller adjustment and improving its applicability to various reaction conditions. This invention achieves automated and precise temperature control of the PTFE polymerization reactor, reducing the workload of on-site operators and even reducing the frequency of operation of the PTFE polymerization reactor during the reaction process by more than 90%.

[0146] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be repeated here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0147] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0148] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0149] It should be noted that in the description of this invention, the word "a" or "an" preceding a component does not exclude the existence of multiple such components. This invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. The use of terms such as first, second, third, etc., is merely for convenience and does not indicate any order. These terms can be understood as part of the component names.

[0150] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0151] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning of the basic inventive concept, can make other changes and modifications to these embodiments.

[0152] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of the invention.

Claims

1. A method for temperature control in a PTFE polymerization reactor, characterized in that, include: The temperature control target data of the PTFE polymerization reactor at each reaction stage were obtained and curve-fitted according to the time series to obtain the temperature change target curve and the feed target curve. Using the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, a multivariate control target prediction was performed to obtain a temperature control scheme with a fitted time series. Based on the target feed curve and the obtained cooling water temperature information, the temperature control scheme is modified so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted according to the modified temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

2. The method as described in claim 1, characterized in that, Before obtaining the target temperature change curve and the target feed curve by performing curve fitting on the time series of the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage, the following steps are also included: Extract the data of the first reaction process with the optimal reaction temperature and the data of the second reaction process with the optimal monomer feed from the pre-set empirical database; Based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature, and based on the first reaction process data, the target temperature change curve for each reaction temperature stage is fitted according to the time series. Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages for monomer feed rate, and the feed target curve for each feeding stage is fitted according to the time series based on the second reaction process data.

3. The method as described in claim 2, characterized in that, Based on the temperature change inflection points in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature. Based on the first reaction process data, target temperature change curves for each reaction temperature stage are fitted according to a time series, including: Based on the temperature change inflection point in the first reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of reaction temperature, resulting in reaction temperature stages including the initial stage, transition stage, violent stage, and stable stage. When the reaction temperature stage is the initial stage, the actual temperature data of the PTFE polymerization reactor is fitted to the first temperature change target curve according to the time series. When the reaction temperature stage is the transition stage, the temperature control target data of the transition stage is fitted into the second temperature change target curve according to the time series. When the reaction temperature stage is the intense stage, the temperature control target data of the intense stage is fitted into the third temperature change target curve according to the time series. When the reaction temperature is in a stable phase, the temperature control target data of the stable phase is fitted into a fourth temperature change target curve according to the time series. Based on the inflection point of temperature change, the first temperature change target curve, the second temperature change target curve, the third temperature change target curve, and the fourth temperature change target curve are sequentially connected to obtain the temperature change target curve of the PTFE polymerization reactor.

4. The method as described in claim 2, characterized in that, Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages for monomer feed rate. Based on the second reaction process data, a feed target curve for each feed stage is fitted according to a time series, including: Based on the inflection point of feed change in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of monomer feed rate to obtain the feed stages including the initial stage, the rising stage and the steady stage. When the feeding stage is the initial stage, the actual feeding data of the PTFE polymerization reactor is fitted to the first feeding target curve according to the time series. When the feeding stage is the rising stage, the feeding control target data of the rising stage is fitted into the second feeding target curve according to the time series; When the feeding stage is in a stable stage, the feeding control target data of the stable stage is fitted into the third feeding target curve according to the time series; Based on the inflection point of the feed change, the first feed change target curve, the second feed change target curve, and the third feed change target curve are sequentially connected to obtain the feed change target curve of the PTFE polymerization reactor.

5. The method as described in claim 1, characterized in that, Using the target curves for temperature change and feed as the controlled variables, and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, a multivariate control target prediction was performed to obtain a temperature control scheme with a fitted time series, including: Based on the extreme values ​​of cooling water flow rate in the PTFE polymerization reactor, the temperature control constraints of the PTFE polymerization reactor are obtained. Based on the temperature control constraints, a multivariate predictive control model is established with the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable. Based on the time series, a temperature control scheme that fits the time series is obtained through a multivariate predictive control model. This temperature control scheme is the cooling water flow rate data curve fitted according to the time series. The mathematical expression for the multivariate predictive control model is as follows: ； In the formula, u ( i ) represents a manipulated variable. x ( i )and y ( i ) represents the controlled variable. n Represents a time point. x ref ( i ) represents the controlled variable x ( i Reference trajectory for each cycle, y ref ( i ) represents the controlled variable y ( i Reference trajectory for each cycle, Q Represented by the controlled variable x ( i The weight matrix of ) R Represented by the controlled variable y ( i The weight matrix of ) f The dynamic equations representing the control prediction model. u(i) max This represents the upper limit of the manipulated variable. x ( i ) min Represents manipulated variables x ( i The lower limit of the target, x ( i ) max Represents manipulated variables x ( i The target upper limit, y ( i ) min Represents manipulated variables y ( i The lower limit of the target, y ( i ) max Represents manipulated variables y ( i The target upper limit.

6. The method as described in claim 1, characterized in that, Based on the target feed curve and the obtained cooling water temperature information, the temperature control scheme is modified to dynamically regulate the cooling water flow rate of the PTFE polymerization reactor according to the modified temperature control scheme, thereby obtaining the optimal reaction temperature of the PTFE polymerization reactor, including: Obtain the temperature information of the cooling water in the PTFE polymerization reactor; Based on the feed target curve and cooling water temperature information, the cooling water demand is obtained. This cooling water demand is an intermediate parameter used to correct the temperature control scheme, obtained by processing the reaction temperature and cooling water temperature using the law of conservation of heat. Based on the cooling water demand, the multivariate predictive control model of the predicted temperature control scheme is modified, and the temperature change target curve and the feed target curve are input into the modified multivariate predictive control model for calculation to obtain the optimal temperature control scheme for the PTFE polymerization reactor. The mathematical expression for the modified multivariate predictive control model is as follows: ； In the formula, u* ( i ) represents the optimal manipulated variable, ∆ u ( i () represents the increment of the manipulated variable. S The weight matrix representing the increment in the manipulated variable, ∆ u ( i ) min ∆ represents the lower bound of the increment of the manipulated variable. u ( i ) max This represents the upper limit of the increment of the manipulated variable. u ( i ) represents a manipulated variable. x ( i )and y ( i ) represents the controlled variable. n Represents a time point. x ref ( i ) represents the controlled variable x ( i Reference trajectory for each cycle, y ref ( i ) represents the controlled variable y ( i Reference trajectory for each cycle, Q Represented by the controlled variable x ( i The weight matrix of ) R Represented by the controlled variable y ( i The weight matrix of ) f The dynamic equations representing the control prediction model. u(i) max This represents the upper limit of the manipulated variable. x ( i ) min Represents manipulated variables x ( i The lower limit of the target, x ( i ) max Represents manipulated variables x ( i The target upper limit, y ( i ) min Represents manipulated variables y ( i The lower limit of the target, y ( i ) max Represents manipulated variables y ( i The target upper limit.

7. The method as described in claim 6, characterized in that, Based on the feed target curve and cooling water temperature information, the cooling water requirement is obtained. This cooling water requirement is an intermediate parameter used to correct the temperature control scheme, obtained by processing the reaction temperature and cooling water temperature using the law of conservation of heat. Based on the feed target curve, obtain the heat released in the PTFE polymerization reactor at each reaction stage; The heat absorbed by the cooling water is obtained based on the temperature difference data of the inlet and outlet of the PTFE polymerization reactor. Based on the heat released and absorbed, and combined with the water demand calculation formula, the cooling water demand of the PTFE polymerization reactor is obtained; The formula for calculating water demand is as follows: ； In the formula, H This represents the cooling water demand. C Represents specific heat capacity. F 2 represents the cooling water flow rate, Δ t Δ represents cumulative time. T The temperature difference between the inlet and outlet of the cooling water. F 1 represents the monomer feed rate. K This represents the proposed amount of exothermic energy.

8. A temperature control system for a PTFE polymerization reactor, characterized in that, include: The target curve acquisition module is used to perform curve fitting on the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage according to the time series to obtain the temperature change target curve and the feed target curve. The control prediction module is used to perform multivariate control target prediction with the temperature change target curve and the feed target curve as the controlled variables and the cooling water flow rate of the PTFE polymerization reactor as the manipulated variable, so as to obtain a temperature control scheme with a fitted time series. The control scheme correction module is used to correct the temperature control scheme based on the feed target curve and the obtained cooling water temperature information, so that the cooling water flow rate of the PTFE polymerization reactor is dynamically adjusted based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

9. A PTFE polymerization reaction apparatus, characterized in that, include: PTFE polymerization reactor; A temperature sensor is installed inside the PTFE polymerization reactor. A feed flow meter is installed on the feed pipe of the PTFE polymerization reactor; The cooling water valve is installed on the cooling water inlet pipe of the PTFE polymerization reactor; The controller is connected to a temperature sensor, a feed flow meter, and a cooling water valve, respectively, and is used to execute the temperature control method steps of the PTFE polymerization reactor as described in any one of claims 1-7.

10. A computer-readable medium having computer-executable instructions stored thereon, characterized in that, When the executable instructions are executed by the processor, they implement the temperature control method steps of the PTFE polymerization reactor as described in any one of claims 1-7.

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