Temperature control method, system, equipment and medium for PTFE (Polytetrafluoroethylene) polymerization reaction kettle

Abstract

The invention relates to a temperature control method, system, equipment and medium for a PTFE polymerization reactor, and the method comprises the steps: carrying out the curve fitting of the obtained temperature control target data of the PTFE polymerization reactor at each reaction stage according to a time sequence, and obtaining a temperature change target curve and a feeding target curve; performing multivariable control target prediction by taking the temperature change target curve and the feeding target curve as controlled variables and taking the cooling water flow of the PTFE polymerization reaction kettle as a manipulated variable to obtain a temperature control scheme of a fitting time sequence; the temperature control scheme is corrected according to the feeding target curve and the obtained temperature information of the cooling water, so that the cooling water flow of the PTFE polymerization reaction kettle is dynamically regulated and controlled based on the corrected temperature control scheme, and the optimal reaction temperature of the PTFE polymerization reaction kettle is obtained. The technical problems that the temperature control means of an existing PTFE polymerization reaction kettle is not timely enough to adjust and low in adaptability are solved.

Description

Technical Field

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

[0002] PTFE (polytetrafluoroethylene) polymerization reactor is a device used to produce PTFE. The control task of PTFE polymerization reactor is to ensure the quality of the reaction product by controlling the reaction pressure, reaction temperature, reaction rate, reaction time and reaction amount. Among them, the reaction temperature will directly affect the reaction rate in the PTFE polymerization reactor. Since the PTFE polymerization reaction is an exothermic reaction, the temperature in the reactor will directly affect the decomposition rate of the initiator. At the same time, the increase in temperature in the reactor will cause the reaction rate to accelerate, and it will also be accompanied by a large amount of heat. When it reaches a certain temperature, if it is not cooled down, it will cause an implosion phenomenon, which will cause the temperature regulation to be out of control and lead to unqualified reaction products. At the same time, when the reaction temperature is higher, the PTFE polymerization reaction is more intense, the pressure in the reactor is lower, and the feed amount of TFE monomer is larger, and then the monomer feed flow rate is also affected by the polymerization reaction rate.

[0003] At present, in order to ensure the reaction temperature stability of the PTFE polymerization reactor in the prior art, a water cooling method is usually adopted. By setting a cold water valve, when the reaction temperature exceeds the set threshold or is lower than the set threshold, the cold water valve is opened or closed to control the temperature of the PTFE polymerization reactor through cooling water.

[0004] However, based on the temperature change of the PTFE polymerization reactor, the manual operation is simulated to control the opening and closing of the cold water to achieve the temperature control of the PTFE polymerization reactor. The control means have no reasonable control target. When the temperature change rate is too fast, the cooling water is turned on to cool down. When the temperature is about to return to temperature, the cooling water is directly and completely closed to prevent the temperature from continuing to drop. Therefore, the existing temperature control scheme of the PTFE polymerization reactor has the following main shortcomings: First, since it is simply adjusted according to the temperature change rate, it cannot adapt to all working conditions. If the reaction is too slow or too fast, it is easy to cause abnormal temperature adjustment. Secondly, when there is a large lag in the change of the polymerization reaction temperature, the temperature adjustment is not timely enough, and the temperature is prone to return to temperature. In addition, the cooling water valve adopts a full-open and full-close adjustment method, which purely simulates manual operation and cannot meet the needs of precise control. Summary of the invention

[0005] 1. Technical issues to be resolved

[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 a PTFE polymerization reactor, which solves the technical problems that the temperature control means of the existing PTFE polymerization reactor are not adjusted in a timely manner and have low adaptability.

[0007] (II) Technical solution

[0008] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, an embodiment of the present invention provides 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 are obtained and curve fitting is performed according to the time series to obtain the temperature change target curve and the feed target curve;

[0011] The temperature change target curve and the feed target curve are used as controlled variables, and the cooling water flow rate of the PTFE polymerization reactor is used as the manipulated variable to perform multivariable control target prediction and obtain the temperature control scheme of the fitting time series.

[0012] According to the feed target curve and the obtained cooling water temperature information, the temperature control scheme is corrected so that the cooling water flow of the PTFE polymerization reactor is dynamically regulated based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

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

[0014] Extracting first reaction process data with optimal reaction temperature and second reaction process data with optimal monomer feed from a preset experience database;

[0015] According to 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 temperature change target curve of each reaction temperature stage is fitted according to a time series;

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

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

[0018] According to 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 an initial stage, a transition stage, a violent stage, and a stable stage;

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

[0020] When the reaction temperature stage is a 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;

[0021] When the reaction temperature stage is a severe stage, fitting the temperature control target data of the severe stage into a third temperature change target curve according to the time series;

[0022] When the reaction temperature stage is a stable stage, fitting the temperature control target data of the stable stage into a fourth temperature change target curve according to the time series;

[0023] According to the temperature change inflection point, 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, according to the feed change inflection point in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of monomer feed amount, and based on the second reaction process data, fitting the feed target curve of each feed stage according to the time series includes:

[0025] According to the feed change inflection point in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages according to the monomer feed amount, and a feed stage including a starting stage, a rising stage and a stable stage is obtained;

[0026] When the feeding stage is the starting stage, the actual feeding data of the PTFE polymerization reactor is fitted into a 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 a second feeding target curve according to the time series;

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

[0029] According to the feed change inflection point, 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, a temperature change target curve and a feed target curve are used as controlled variables, and the cooling water flow rate of the PTFE polymerization reactor is used as a manipulated variable to perform multivariable control target prediction, and a temperature control scheme for obtaining a fitting time series includes:

[0031] According to the extreme value of the cooling water flow rate in the PTFE polymerization reactor, the temperature control constraint condition of the PTFE polymerization reactor is obtained;

[0032] According to the temperature control constraint conditions, a multivariable predictive control model was 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] According to the time series, a temperature control scheme fitting the time series is obtained through a multivariable predictive control model, and the temperature control scheme is a cooling water flow data curve fitting the time series;

[0034] Among them, the mathematical expression of the multivariable predictive control model is:

[0035]

[0036] In the formula, u(i) represents the manipulated variable, x(i) and y(i) represent the controlled variables, n represents the time node, x ref (i) represents the reference trajectory of the controlled variable x(i) in each cycle, y ref (i) represents the reference trajectory of the controlled variable y(i) in each cycle, 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, u(i) max represents the upper limit of the manipulated variable, x(i) min represents the target lower limit of the manipulated variable x(i), x(i) max represents the target upper limit of the manipulated variable x(i), y(i) min represents the target lower limit of the manipulated variable y(i), y(i) max Represents the target upper limit of the manipulated variable y(i).

[0037] Optionally, according to the feed target curve and the obtained cooling water temperature information, the temperature control scheme is corrected so that the cooling water flow rate of the PTFE polymerization reactor is dynamically regulated based on the corrected temperature control scheme, and obtaining the optimal reaction temperature of the PTFE polymerization reactor includes:

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

[0039] According to the feed target curve and the temperature information of the cooling water, the cooling water demand is obtained. The cooling water demand is an intermediate parameter for correcting the temperature control scheme obtained by processing the reaction temperature and the cooling water temperature using the law of conservation of heat;

[0040] According to the cooling water demand, the multivariable predictive control model for predicting the temperature control scheme is modified, and the temperature change target curve and the feed target curve are input into the modified multivariable predictive control model for calculation to obtain the optimal temperature control scheme for the PTFE polymerization reactor;

[0041] Among them, the mathematical expression of the modified multivariable predictive control model is:

[0042]

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

[0044] Optionally, the cooling water requirement is obtained according to the feed target curve and the temperature information of the cooling water. The cooling water requirement is an intermediate parameter for correcting the temperature control scheme obtained by processing the reaction temperature and the cooling water temperature using the law of conservation of heat, and includes:

[0045] According to the feed target curve, the heat released by the PTFE polymerization reactor in each reaction stage is obtained;

[0046] According to the temperature difference data of the cooling water inlet and outlet of the PTFE polymerization reactor, the absorbed heat of the cooling water is obtained;

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

[0048] The water demand calculation formula is:

[0049]

[0050] Where 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 monomer feed amount, and K represents the proposed heat release energy.

[0051] In a second aspect, an embodiment of the present invention provides a temperature control system for a PTFE polymerization reactor, comprising:

[0052] A control 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 a time series to obtain a temperature change target curve and a feed target curve;

[0053] A control prediction module is used to predict the multivariable control target 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 to obtain a temperature control scheme that fits the time series;

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

[0055] In a third aspect, an embodiment of the present invention provides a PTFE polymerization reaction device, comprising:

[0056] PTFE polymerization reactor;

[0057] A temperature sensor is arranged in the PTFE polymerization reactor;

[0058] A feed flow meter is arranged on a feed pipeline of the PTFE polymerization reactor;

[0059] A cooling water valve is provided 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] In a fourth aspect, an embodiment of the present invention provides a computer-readable medium having computer executable instructions stored thereon, and when the executable instructions are executed by a processor, the temperature control method steps of the PTFE polymerization reactor described above are implemented.

[0062] (III) Beneficial effects

[0063] The beneficial effects of the present invention are as follows: the temperature control method of the PTFE polymerization reactor of the present invention adopts the fitting temperature change target curve and the feed target curve as dual control targets, seeks the optimal solution for cooling water adjustment of the PTFE polymerization reactor through multivariable predictive control, and corrects the optimal solution through the temperature information of the cooling water, and finally obtains the technical means of the cooling water flow control scheme of the fitting time series. Compared with the prior art, the present invention fits multiple control target curves, so that the control adjustment is adjusted within the expected target value, the temperature control is standardized, the control effect is improved, the labor intensity of the on-site operators is reduced, and the operation frequency of the PTFE polymerization reactor during the reaction process is reduced by more than 90%; at the same time, the concept of cooling water flow control proposed by the present invention can ensure that the cooling water volume is within the appropriate range under the premise of temperature lag adjustment to prevent exceeding the adjustment range. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A schematic flow chart of a temperature control method for a PTFE polymerization reactor provided in one embodiment of the present invention;

[0065] Figure 2 A temperature variation target curve fitting diagram of a PTFE polymerization reactor provided in one embodiment of the present invention;

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

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

[0068] Figure 5 This is an application effect diagram of the temperature control solution of the PTFE polymerization reactor provided by one embodiment of the present invention;

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

[0070] Figure 7 A schematic diagram of the composition of a PTFE polymerization reaction equipment provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0071] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0072] refer to Figure 1As shown, a temperature control method for a PTFE polymerization reactor proposed in an embodiment of the present invention comprises: performing curve fitting on the acquired temperature control target data of the PTFE polymerization reactor in each reaction stage according to a time series to obtain a temperature change target curve and a feed target curve; performing multivariate control target prediction with 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 to obtain a temperature control scheme of the fitting time series; and correcting 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 regulated based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

[0073] This embodiment adopts the fitting temperature change target curve and the feed target curve as dual control targets, seeks the optimal solution for cooling water adjustment of the PTFE polymerization reactor through multivariable predictive control, and corrects the optimal solution through the temperature information of the cooling water, and finally obtains the technical means of the cooling water flow control scheme of the fitting time series. Compared with the prior art, this embodiment fits multiple control target curves, so that the control adjustment is adjusted within the expected target value, the temperature control is standardized, the control effect is improved, the labor intensity of the on-site operators is reduced, and the operation frequency of the PTFE polymerization reactor during the reaction process is reduced by more than 90%; at the same time, the concept of cooling water flow control proposed in this embodiment can ensure that the cooling water volume is within the appropriate range under the premise of temperature lag adjustment to prevent exceeding the adjustment range.

[0074] In order to better understand the above technical solution, 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 accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

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

[0076] S100, performing 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 a temperature change target curve and a feed target curve.

[0077] In the PTFE polymerization process, the reaction temperature not only directly affects the polymerization reaction rate, but also affects the feed flow rate, thereby indirectly affecting the polymerization reaction rate. For example, when the reaction temperature is higher, the PTFE polymerization reaction is more intense, the pressure in the reactor is lower, and the monomer feed amount is larger. When the feed monomer accumulates too much, it will directly affect the polymerization reaction rate and product production efficiency.

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

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

[0080] The experience database stores the experience data of operators performing stable temperature control. The experience data for a period of time (for example, all the experience data within 1 year) is selected, some abnormal reactions are eliminated, and the experience data within the time period 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. Divide the reaction process of the PTFE polymerization reactor into stages of reaction temperature according to the temperature change inflection point in the first reaction process data, and fit a temperature change target curve of each reaction temperature stage according to a time series based on the first reaction process data.

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

[0083] S121. According to 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 to obtain reaction temperature stages including a start stage, a transition stage, a violent stage and a stable stage.

[0084] Since the heat absorbed and released by the PTFE polymerization reaction varies greatly in different reaction stages, the operator's operational experience data is used to select the appropriate temperature inflection point to control the cooling water valve to move in advance, so that each stage is matched with the corresponding control scheme and related parameters to achieve precise control of the temperature of the PTFE polymerization reactor.

[0085] S122a, when the reaction temperature stage is the start stage, fitting the actual temperature data of the PTFE polymerization reactor into a first temperature change target curve according to the time series.

[0086] When the reaction temperature stage is the initial stage, the monomer feed flow rate and the temperature in the PTFE polymerization reactor are both low, and the heat released is limited, which can only ensure that the PTFE polymerization reaction can proceed normally. Therefore, in the initial stage, the PTFE polymerization reactor does not need to use cooling water to remove heat. The initial temperature and reaction time of this stage are mainly affected by the cooling of the PTFE polymerization reactor during the evacuation and replacement process and the initiator.

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

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

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

[0090] When the reaction temperature stage is the intense stage, the polymerization reaction begins to react violently at the initial temperature inflection point of this stage because the feed monomers have accumulated to a certain amount, and the temperature begins to rise. At this time, a large amount of cooling water is required to ensure that a large amount of heat can be taken away. The termination temperature inflection point of the intense stage is selected by the change in the reaction rate, and the position with the maximum reaction rate is taken as the termination inflection point of the intense stage. This selection method can eliminate the lag caused by temperature, steadily reduce the flow of cold water, and greatly reduce the probability of operating temperature recovery due to a sharp drop in reaction rate.

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

[0092] When the reaction temperature stage is a stable stage, the reaction rate decreases slowly and the heat released is relatively reduced. Therefore, it is necessary to slowly turn down the cooling water to take away the excess heat and make the temperature rise slowly. The initial temperature inflection point of this stage is the termination temperature inflection point of the violent stage.

[0093] S123. According to the temperature change inflection point, 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.

[0094] In a specific embodiment, the termination temperature inflection point of the first temperature change target curve is connected with 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 with 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 with the initial temperature inflection point of the fourth temperature change target curve. The temperature change target curve of the PTFE polymerization reactor finally obtained is as follows: Figure 2 shown.

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

[0096] In this embodiment, the fitting timing of the monomer feed is different from the reaction temperature, because the speed of the polymerization reaction can be most intuitively displayed in the monomer feed. Therefore, when the polymerization reaction is too fast or too slow, it is easy to cause the feed target curve to not match the actual reaction data, thereby affecting the temperature control. In this embodiment, by analyzing the operator's experience data, the feed data after the reaction rate reaches the set threshold is selected for separate timing to obtain the feed target curve, which improves the curve matching degree and thus improves the temperature control effect.

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

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

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

[0100] When the feeding stage is the initial stage, the feed monomer is provided by the upstream device and its properties cannot be controlled. The initial reaction temperature is greatly affected by the feed monomer and initiator, so the feed target curve in this stage changes with the actual feed data and has no fixed value.

[0101] S132b, when the feeding stage is the rising stage, fitting the feeding control target data of the rising stage into a second feeding target curve according to the time series.

[0102] When the feeding stage is the rising stage, this stage is the key stage of control. It is necessary to ensure that the monomer feed is not higher than the set target threshold in this stage. If it is higher than the target threshold, a large number of polymerization reactions will be carried out in this stage, which will lead to a slower reaction in the next stage, thus affecting the reaction time. And the initial point of feed in the rising stage is 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 a 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 to the fitting curve as possible during the control process of this stage to avoid excessive deviation in reaction time that affects product quality.

[0105] S133. According to the feed change inflection point, 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.

[0106] In a specific embodiment, the first feed change target curve is the initial feed flow rate of the PTFE polymerization reactor, the initial feed inflection point of the second feed change target curve is connected with the first feed change target curve, and the termination feed inflection point of the second feed change target curve is connected with the third feed change target curve. The feed change target curve of the PTFE polymerization reactor finally obtained is as follows: Figure 3 shown.

[0107] S200, 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 multivariable control target prediction, and 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, obtaining temperature control constraint conditions of the PTFE polymerization reactor according to the extreme value of the cooling water flow rate in the PTFE polymerization reactor.

[0110] S220. According to the temperature control constraint conditions, a multivariable predictive control model is established with 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.

[0111] The mathematical expression of the multivariable predictive control model is:

[0112]

[0113] In the formula, u(i) represents the manipulated variable, x(i) and y(i) represent the controlled variables, n represents the time node, x ref (i) represents the reference trajectory of the controlled variable x(i) in each cycle, y ref (i) represents the reference trajectory of the controlled variable y(i) in each cycle, 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, u(i) max represents the upper limit of the manipulated variable, x(i) min represents the target lower limit of the manipulated variable x(i), x(i) max represents the target upper limit of the manipulated variable x(i), y(i) min represents the target lower limit of the manipulated variable y(i), y(i) max Represents the target upper limit of the manipulated variable y(i).

[0114] S230. According to the time series, a temperature control scheme fitting the time series is obtained through a multivariable predictive control model. The temperature control scheme is a cooling water flow data curve fitted according to the time series.

[0115] S300, according to the feed target curve and the obtained cooling water temperature information, the temperature control scheme is corrected so that the cooling water flow of the PTFE polymerization reactor is dynamically regulated based on the corrected 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, obtaining the temperature information of the cooling water of the PTFE polymerization reactor.

[0118] S320. According to the feed target curve and the temperature information of the cooling water, the cooling water requirement is obtained. The cooling water requirement is an intermediate parameter for correcting the temperature control scheme obtained by processing the reaction temperature and the cooling water temperature using the law of conservation of heat.

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

[0120] S321. According to the feed target curve, the heat released by the PTFE polymerization reactor in each reaction stage is obtained.

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

[0122] Q 放 =F1·Δt·K

[0123] Where F1 represents the monomer feed amount, K represents the proposed exothermic energy, and Δt represents the cumulative time.

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

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

[0126] Q 吸 =C·F2·Δt·ΔT

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

[0128] S323. According to the released heat and absorbed heat, combined with the water demand calculation formula, the cooling water demand of the PTFE polymerization reactor is obtained.

[0129] The water demand calculation formula is:

[0130]

[0131] Where H represents the cooling water demand.

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

[0133] During the commissioning process of the temperature control scheme, the temperature and rate may be too high or too low, which may easily lead to a low degree of water demand matching in a short period of time, affecting temperature control. Therefore, it is necessary to select the deviation value between the actual temperature, rate and the fitting to correct the temperature control scheme.

[0134] Among them, the mathematical expression of the modified multivariable predictive control model is:

[0135]

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

[0137] In a specific embodiment, when the temperature of the PTFE polymerization reactor is controlled, first, the target control curve of the PTFE polymerization reactor is obtained, such as Figure 2 and Figure 3 Then, Figure 2 and Figure 3 The curve data shown in FIG. 1 is input into the multivariable predictive control model; then, the output result of the multivariable predictive control model is subjected to curve fitting according to the time series to obtain the following: Figure 4 Finally, the control scheme including the cooling water demand curve is deployed to the controller of the cooling water valve, and the controller controls the cooling water flow in real time through the cooling water demand curve, so that the temperature control effect of the PTFE polymerization reactor is as follows: Figure 5 As shown in (the smooth curve is the predicted control effect, and the fluctuation curve is the actual control effect). Among them, the modified model diagram of the temperature control scheme is as follows Figure 6 As shown in the figure, 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 volume within a more appropriate range to ensure stable temperature control without temperature rebound.

[0138] In addition, the embodiment of the present invention also provides a temperature control system for a PTFE polymerization reactor, comprising:

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

[0140] The control prediction module is used to predict the multivariable control target 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 to obtain the temperature control scheme of the fitting time series.

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

[0142] Also, reference Figure 7As shown, an embodiment of the present invention further proposes a PTFE polymerization reaction equipment, including: a PTFE polymerization reactor; a temperature sensor, arranged in the PTFE polymerization reactor; a feed flow meter, arranged on the feed pipe of the PTFE polymerization reactor; a cooling water valve, arranged on the cooling water inlet pipe of the PTFE polymerization reactor; a controller, respectively connected to the temperature sensor, the feed flow meter and the cooling water valve, for executing the temperature control method steps of the PTFE polymerization reactor described above.

[0143] In this embodiment, Figure 7 As shown, pure water and initiator are added to the PTFE polymerization reactor in sequence. After the leak test is completed, the stirrer inside the PTFE polymerization reactor is turned on, and the oxygen in the reactor is removed by evacuation and nitrogen replacement. After the oxygen content is qualified, TFE monomer is added. After the pressure is increased, the TFE monomer enters the polymerization reaction stage. During the reaction, the reactor pressure must be kept constant, and the temperature of the reactor must rise steadily by adjusting the cooling water flow. There should be no downward trend during the reaction, and the temperature should not exceed the set value at the end of the reaction. After the reaction is completed, the PTFE product obtained by polymerization is discharged to the subsequent washing and drying process, and finally the reactor is cleaned to prepare for the production of the next reactor.

[0144] Finally, the embodiment of the present invention further provides a computer-readable medium on which computer executable instructions are stored. When the executable instructions are executed by a processor, the temperature control method steps of the PTFE polymerization reactor described above are implemented.

[0145] In summary, the embodiments of the present invention propose a temperature control method, system, equipment and medium for a PTFE polymerization reactor. The present invention is based on the process analysis of the PTFE polymerization reaction, establishes a control model of cooling water, reaction temperature and reaction rate, and uses a controller to perform reaction temperature control to seek the optimal solution for cooling water adjustment. At the same time, according to the principle of heat balance, the cooling water demand is continuously calculated, and a reference value is added to the controller adjustment to improve the applicability to various reaction conditions. The present invention realizes automatic and precise control of the temperature of the PTFE polymerization reactor, reduces the labor intensity of on-site operators, and even reduces the operation frequency of the PTFE polymerization reactor during the reaction by more than 90%.

[0146] Since the system / device described in the above embodiments of the present invention is a system / device used to implement the method of the above embodiments of the present invention, a person skilled in the art can understand the specific structure and deformation of the system / device based on the method described in the above embodiments of the present invention, and thus will not be described in detail here. All systems / devices used in the method of the above embodiments of the present invention belong to the scope of protection of the present invention.

[0147] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented 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] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0149] It should be noted that in the description of the present invention, the word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The present invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. The use of the words first, second, third, etc., is only for convenience of expression and does not indicate any order. These words may be understood as part of the name of the component.

[0150] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations 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 one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0151] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments after obtaining the basic inventive concepts.

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

Claims

1. A temperature control method for a PTFE polymerization reactor, characterized in that: include: The temperature control target data of the PTFE polymerization reactor at each reaction stage are obtained and curve fitting is performed according to the time series to obtain the temperature change target curve and the feed target curve; The temperature change target curve and the feed target curve are used as controlled variables, and the cooling water flow rate of the PTFE polymerization reactor is used as the manipulated variable to perform multivariable control target prediction and obtain the temperature control scheme of the fitting time series. According to the feed target curve and the obtained cooling water temperature information, the temperature control scheme is corrected so that the cooling water flow of the PTFE polymerization reactor is dynamically regulated based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

2. The method according to claim 1, characterized in that Before the acquired temperature control target data of the PTFE polymerization reactor at each reaction stage are subjected to curve fitting according to the time series to obtain the temperature change target curve and the feed target curve, the following steps are also included: Extracting first reaction process data with optimal reaction temperature and second reaction process data with optimal monomer feed from a preset experience database; According to 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 temperature change target curve of each reaction temperature stage is fitted according to a time series; According to the feed change inflection point in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of monomer feed amount, and based on the second reaction process data, the feed target curve of each feed stage is fitted according to the time series.

3. The method according to claim 2, characterized in that According to 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 temperature change target curve of each reaction temperature stage is fitted according to the time series, including: According to 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 an initial stage, a transition stage, a violent stage, and a stable stage; When the reaction temperature stage is the start stage, the actual temperature data of the PTFE polymerization reactor is fitted into a first temperature change target curve according to the time series; When the reaction temperature stage is a 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; When the reaction temperature stage is a severe stage, fitting the temperature control target data of the severe stage into a third temperature change target curve according to the time series; When the reaction temperature stage is a stable stage, fitting the temperature control target data of the stable stage into a fourth temperature change target curve according to the time series; According to the temperature change inflection point, 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 according to claim 2, characterized in that According to the feed change inflection point in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages of monomer feed amount, and based on the second reaction process data, the feed target curve of each feed stage is fitted according to the time series, including: According to the feed change inflection point in the second reaction process data, the reaction process of the PTFE polymerization reactor is divided into stages according to the monomer feed amount, and a feed stage including a starting stage, a rising stage and a stable stage is obtained; When the feeding stage is the starting stage, the actual feeding data of the PTFE polymerization reactor is fitted into a 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 a second feeding target curve according to the time series; When the feeding stage is a stable stage, the feeding control target data of the stable stage is fitted into a third feeding target curve according to the time series; According to the feed change inflection point, 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 according to claim 1, characterized in that Taking 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, the multivariable control target prediction is carried out to obtain the temperature control scheme of the fitting time series, including: According to the extreme value of the cooling water flow rate in the PTFE polymerization reactor, the temperature control constraint condition of the PTFE polymerization reactor is obtained; According to the temperature control constraint conditions, a multivariable predictive control model was 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. According to the time series, a temperature control scheme fitting the time series is obtained through a multivariable predictive control model, and the temperature control scheme is a cooling water flow data curve fitting the time series; Among them, the mathematical expression of the multivariable predictive control model is: In the formula, u(i) represents the manipulated variable, x(i) and y(i) represent the controlled variables, n represents the time node, x ref (i) represents the reference trajectory of the controlled variable x(i) in each cycle, y ref (i) represents the reference trajectory of the controlled variable y(i) in each cycle, 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, u(i) max represents the upper limit of the manipulated variable, x(i) min represents the target lower limit of the manipulated variable x(i), x(i) max represents the target upper limit of the manipulated variable x(i), y(i) min represents the target lower limit of the manipulated variable y(i), y(i) max Represents the target upper limit of the manipulated variable y(i).

6. The method according to claim 1, characterized in that According to the feed target curve and the obtained cooling water temperature information, the temperature control scheme is corrected so that the cooling water flow of the PTFE polymerization reactor is dynamically regulated based on the corrected temperature control scheme. The optimal reaction temperature of the PTFE polymerization reactor is obtained, including: Obtaining the temperature information of the cooling water of the PTFE polymerization reactor; According to the feed target curve and the temperature information of the cooling water, the cooling water demand is obtained. The cooling water demand is an intermediate parameter for correcting the temperature control scheme obtained by processing the reaction temperature and the cooling water temperature using the law of conservation of heat; According to the cooling water demand, the multivariable predictive control model for predicting the temperature control scheme is modified, and the temperature change target curve and the feed target curve are input into the modified multivariable predictive control model for calculation to obtain the optimal temperature control scheme for the PTFE polymerization reactor; Among them, the mathematical expression of the modified multivariable predictive control model is: In the formula, u*(i) represents the optimal operating variable, Δu(i) represents the increment of the operating variable, S represents the weight matrix of the increment in the operating variable, and Δu(i) min Represents the lower limit of the increment of the manipulated variable, Δu(i) max Represents the upper limit of the increment of the manipulated variable.

7. The method according to claim 6, characterized in that According to the feed target curve and the temperature information of the cooling water, the cooling water demand is obtained. The cooling water demand is an intermediate parameter for correcting the temperature control scheme obtained by processing the reaction temperature and the cooling water temperature using the law of conservation of heat, including: According to the feed target curve, the heat released by the PTFE polymerization reactor in each reaction stage is obtained; According to the temperature difference data of the cooling water inlet and outlet of the PTFE polymerization reactor, the absorbed heat of the cooling water is obtained; According to the released heat and absorbed heat, combined with the water demand calculation formula, the cooling water demand of the PTFE polymerization reactor is obtained; The water demand calculation formula is: Where 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 monomer feed amount, and K represents the proposed heat release energy.

8. A temperature control system for a PTFE polymerization reactor, characterized in that: include: A control 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 a time series to obtain a temperature change target curve and a feed target curve; A control prediction module is used to predict the multivariable control target 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 to obtain a temperature control scheme that fits the time series; The control scheme correction module is used to correct the temperature control scheme according to the feed target curve and the obtained cooling water temperature information, so that the cooling water flow of the PTFE polymerization reactor can be dynamically regulated based on the corrected temperature control scheme to obtain the optimal reaction temperature of the PTFE polymerization reactor.

9. A PTFE polymerization reaction equipment, characterized in that: include: PTFE polymerization reactor; A temperature sensor is arranged in the PTFE polymerization reactor; A feed flow meter is arranged on a feed pipeline of the PTFE polymerization reactor; A cooling water valve is provided on the cooling water inlet pipe of the PTFE polymerization reactor; 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 as described in any one of claims 1 to 7.

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

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