Gas-liquid two-phase continuous flow reactor and liquid level control method

Abstract

The invention relates to the technical field of reactor liquid level control, in particular to a gas-liquid two-phase continuous flow type reactor and a liquid level control method, and the method comprises the following steps: obtaining relevant parameters in the operation process of the reactor in real time; acquiring a liquid level stable value and a liquid level deviation value of the reactor at the current moment; obtaining the fitness of each parameter vector; in the process of iteratively acquiring the optimal parameter vector at the current moment by using the intelligent optimization algorithm, acquiring the convergence factor adjustment rate during each iteration based on the closeness degree between the fitness of the parameter vector during each iteration and the distance between the parameter vectors; further acquiring a convergence factor during each iteration; and controlling the liquid level of the gas-liquid two-phase continuous flow reactor by utilizing the optimal parameter vector and combining a PID (Proportion Integration Differentiation) control algorithm. The invention aims to improve the stability of controlling the liquid level of the reactor.

Description

Technical Field

[0001] This application relates to the technical field of reactor liquid level control, and specifically relates to a gas-liquid two-phase continuous flow reactor and a liquid level control method. Background Art

[0002] A continuous flow reactor refers to a device in which reactants flow into the reactor in a continuous manner and reaction products flow out of the reactor in a continuous manner. Its working principle is to maintain stable reaction conditions in the reactor and keep the reaction ongoing by continuously inputting reactants and collecting products.

[0003] Liquid level is an important control parameter in gas-liquid phase reactions. If the feed is too small and the liquid level in the reactor is too low, the stirring effect on the mixed reactants in the gas-liquid two-phase continuous flow reactor is insufficient, resulting in a decline in the reaction effect. If the feed is too much and the liquid level in the reactor is too high, the reactor pressure is too high, leading to an increased safety risk. However, due to the stirring effect of the magnetic stirrer in the gas-liquid two-phase continuous flow reactor and the violent flow of the reactants in the gas-liquid two-phase state, there are large fluctuations in the liquid level in the reactor, and the existing PID (Proportional Integral Derivative) control algorithm is difficult to achieve relatively stable liquid level control, affecting the reaction effect. Summary of the Invention

[0004] In view of the above, it is necessary to provide a gas-liquid two-phase continuous flow reactor and a liquid level control method, which improve the stability of controlling the liquid level of the reactor compared with traditional liquid level control methods:

[0005] In the first aspect, an embodiment of the present application provides a gas-liquid two-phase continuous flow reactor. The gas-liquid two-phase continuous flow reactor is a new type of continuous flow reaction device combining a magnetic stirring reactor and a tubular reactor. All parts of the gas-liquid two-phase continuous flow reactor that come into contact with the reactants are made of C276 Hastelloy material; there is a magnetic stirrer in the gas-liquid two-phase continuous flow reactor; the reactants of the gas-liquid two-phase continuous flow reactor include liquid reactants and gaseous reactants. Among them, the mixed reactants of the liquid reactants and gaseous reactants during the reaction process are called gas-liquid two-phase mixed reactants.

[0006] In one of the embodiments, there are multiple layers of stirring paddles in the gas-liquid two-phase continuous flow reactor. The stirring paddle above the feed inlet is a downward-pushing type, and the stirring paddle below the feed inlet is an upward-pushing type. There is a static mixer in the tubular reactor.

[0007] In the second aspect, an embodiment of the present application further provides a liquid level control method for a gas-liquid two-phase continuous flow reactor. The method includes the following steps:

[0008] Obtain the liquid level data, pressure data of the gas-liquid two-phase continuous flow reactor, the loop current of the magnetic stirrer, and the feed flow rates of the liquid reactant and the gas reactant in real time, and obtain the ideal liquid level, ideal pressure of the gas-liquid two-phase continuous flow reactor, and the ideal loop current of the magnetic stirrer;

[0009] Based on the distribution of all liquid level data within a preset time period adjacent to the current moment, and the difference between the liquid level data and the ideal liquid level, obtain the liquid level stability value of the reactor at the current moment;

[0010] Based on the liquid level stability value, combined with the degree of deviation of the liquid level data from the ideal liquid level, the degree of deviation of the pressure data from the ideal pressure, and the degree of deviation of the loop current from the ideal loop current at the current moment, obtain the liquid level deviation value of the reactor at the current moment;

[0011] Preset multiple parameter vectors of the PID control algorithm. Based on the pressure data at the current moment, the feed flow rates of the liquid reactant and the gas reactant, and the average level of the liquid level data within the preset time period, and combined with the parameters of the stirring paddle, the electrical parameters of the magnetic stirrer, the viscosity and elastic coefficient of the gas-liquid two-phase mixed reactant, model the flow field of the gas-liquid two-phase mixed reactant and the magnetic stirrer, and evaluate the control effects of each parameter vector based on the obtained model to obtain the fitness of each parameter vector;

[0012] Based on the multiple parameter vectors, use the intelligent optimization algorithm to iteratively obtain the optimal parameter vector at the current moment. Among them, based on the degree of proximity between the fitness values of the parameter vectors during each iteration, and the distance between the parameter vectors, obtain the convergence factor adjustment rate during each iteration;

[0013] Based on the convergence factor adjustment rate during each iteration, combined with the preset minimum convergence factor, obtain the convergence factor during each iteration;

[0014] Use the optimal parameter vector, combined with the PID control algorithm, to control the liquid level of the gas-liquid two-phase continuous flow reactor.

[0015] In one embodiment, the process of obtaining the liquid level stability value is as follows:

[0016] Record the degree of dispersion of each liquid level data and the liquid level data at its multiple adjacent moments as the adjacent dispersion degree of each liquid level data;

[0017] Form a liquid level data sequence with all liquid level data within a preset time period adjacent to the current moment, and equally divide the liquid level data sequence into a preset number of subsequences;

[0018] The expression of the liquid level stability value of the reactor at the current moment is:

[0019] Wherein, S represents the stable value of the liquid level in the reactor at the current moment; exp() represents the exponential function with the natural constant as the base; C represents the sum of the proximity dispersions of all liquid level data in the liquid level data sequence; L represents the number of subsequences; σ i , respectively represent the dispersion degree and the mean value of all liquid level data in the i-th subsequence; h 0 represents the ideal liquid level of the reactor.

[0020] In one embodiment, the process of obtaining the liquid level deviation value is as follows:

[0021] The difference between the liquid level data and the ideal liquid level, the difference between the pressure data and the ideal pressure, and the difference between the loop current and the ideal loop current are combined to form a liquid level deviation vector;

[0022] The expression of the liquid level deviation value of the reactor at the current moment is:

[0023] Wherein, E represents the liquid level deviation value of the reactor at the current moment; A represents the modulus of the liquid level deviation vector at the current moment; S represents the stable value of the liquid level in the reactor at the current moment; f represents the difference between the liquid level data and the ideal liquid level at the current moment.

[0024] In one embodiment, the method for obtaining the fitness is as follows: Based on the obtained model, the liquid level deviation values under the control of each parameter vector are obtained, and the calculation result of the time multiplied by the absolute error integral index of the liquid level deviation values under the control of each parameter vector is used as the fitness of each parameter vector.

[0025] In one embodiment, the expression of the convergence factor adjustment rate is:

[0026] Wherein, R j represents the convergence factor adjustment rate at the j-th iteration; norm() represents the normalization operation; F j,min represents the minimum value among the fitnesses of all parameter vectors at the j-th iteration; W represents the number of parameter vectors in the population of the particle swarm algorithm; D j,w represents the distance between the w-th parameter vector and the parameter vector with the minimum fitness at the j-th iteration; F j,w represents the fitness of the w-th parameter vector at the j-th iteration; ε represents a preset value greater than 0.

[0027] In one embodiment, the process of obtaining the convergence factor is as follows:

[0028] Calculate the product of the convergence factor adjustment rate and the preset convergence factor adjustment value at each iteration;

[0029] The convergence factor is the sum of the product and a preset minimum convergence factor.

[0030] In one embodiment, the method for controlling the liquid level of the gas-liquid two-phase continuous flow reactor is as follows: Three components in the optimal parameter vector are respectively used as the proportional parameter, integral parameter, and derivative parameter of the PID control algorithm. The liquid level deviation value of the reactor at the current moment is used as the input of the PID control algorithm, and the opening degree of the valve at the liquid reactant feed inlet is output to control the liquid level of the gas-liquid two-phase continuous flow reactor.

[0031] In one embodiment, when controlling the liquid level of the gas-liquid two-phase continuous flow reactor, the method for controlling the feed flow rate of the gaseous reactant is as follows:

[0032] Based on the feed flow rate of the liquid reactant at the current moment, calculate the required flow rate of the gaseous reactant at the current moment. The difference between the feed flow rate of the gaseous reactant and the required flow rate at the current moment is used as the input of the PID control algorithm, and the opening degree of the valve at the gaseous reactant feed inlet is output to control the feed flow rate of the gaseous reactant.

[0033] This application has at least the following beneficial effects:

[0034] The gas-liquid two-phase continuous flow reactor of this application combines a magnetic stirring reactor and a tubular reactor, successfully integrating the advantageous characteristics of both. Among them, the application of the magnetic stirring method effectively solves the problems of pressure resistance limitation and heat generation due to friction existing in traditional mechanical stirring. And in the gas-liquid two-phase continuous flow reactor, all parts in contact with the reactants are made of C276 Hastelloy material, making the gas-liquid two-phase continuous flow reactor have corrosion resistance and pressure resistance performance;

[0035] Furthermore, in terms of liquid level control, deeply analyze the influence mechanism of the reactor stirring structure on the degree of liquid level fluctuation, make full use of the correlation between the loop current of the magnetic stirrer, the pressure data of the reactor and the liquid level, accurately obtain the liquid level deviation value, and reduce the influence of the eddy current of the gas-liquid two-phase mixed reactants on the estimation of the liquid level deviation;

[0036] Furthermore, with the help of the model simulation platform and the particle swarm algorithm, more accurately determine the control parameters of the PID control algorithm, combine the liquid level deviation value with the PID control algorithm, and control the opening degree of the valve at the liquid reactant feed inlet to improve the stability of controlling the liquid level of the reactor. Description of the Drawings

[0037] To more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0038] Figure 1 The structural diagram of a gas-liquid two-phase continuous flow reactor provided by an embodiment of the present application;

[0039] Figure 2 The step flowchart of a liquid level control method for a gas-liquid two-phase continuous flow reactor provided by an embodiment of the present application;

[0040] Figure 3 The control flowchart of the electric proportional regulating valve at the liquid reactant feed port;

[0041] Figure 4 The control flowchart of the electric proportional regulating valve at the gas reactant feed port. Detailed implementation manners

[0042] In the description of the embodiments of the present application, words such as "exemplary", "or", "for example", etc. are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, using words such as "exemplary", "or", "for example", etc. aims to present relevant concepts in a specific manner.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. It should be understood that unless otherwise stated in the present application, " / " means "or".

[0044] In addition, it should be noted that the terms "first" and "second" in the present application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0045] The following will specifically describe the structure of a gas-liquid two-phase continuous flow reactor provided by the present application with reference to the accompanying drawings.

[0046] Please refer to Figure 1 , which shows the structural diagram of a gas-liquid two-phase continuous flow reactor provided by an embodiment of the present application, Figure 1The names of the components of the gas-liquid two-phase continuous flow reactor are as follows: 1. Coiled pipe, 2. Tank head, 3. Tank cylinder, 4. Flange, 5. Magnetic stirrer; the names of the pipe orifices of the gas-liquid two-phase continuous flow reactor are as follows: a. Discharge port, b. Medium inlet, c. Medium outlet, d. Liquid reactant inlet, e. Gas reactant inlet, f. Stirring port. The nominal size of the discharge port Φ12 indicates that the nominal diameter of the pipe material is 12 mm, and the nominal size of the medium inlet Φ22×3.5 indicates that the nominal diameter of the pipe material is 22 mm and the wall thickness is 3.5 mm. The specific dimension information of the gas-liquid two-phase continuous flow reactor is as Figure 1 shown and will not be elaborated in this application.

[0047] The gas-liquid two-phase continuous flow reactor is a new type of continuous flow reaction device combining a magnetic stirring reactor and a tubular reactor, integrating the advantages of the two types of reactors. The magnetic stirring solves the pressure resistance problem of mechanical stirring and the heat generation caused by friction of mechanical stirring. Moreover, for all parts of the gas-liquid two-phase continuous flow reactor that come into contact with the reactants, the material is c276 Hastelloy, which is corrosion-resistant and pressure-resistant. At the same time, the height of the right coiled pipe is raised to the liquid level in the ideal state of the reactor, ensuring that when the reactant feed is sufficient, the liquid level of the mixed reactants at the stirring paddle can be maintained near the ideal liquid level.

[0048] There are 6 layers of stirring paddles in the gas-liquid two-phase continuous flow reactor. Among them, the 2 layers above the feed port are of the downward-pushing type, and the 4 layers below the feed port are of the upward-pushing type. Under the high-speed stirring of the magnetic stirrer, the gas reactants and liquid reactants quickly disperse and mix fully in the reaction cavity. Subsequently, the mixed reactants enter the tubular reactor, where there is a special static mixer to mix the reactants again. Finally, after the reaction is complete, the material is discharged at the discharge port to complete the gas-liquid two-phase reaction. The mixed reactants of the liquid reactants and gas reactants during the reaction process are called gas-liquid two-phase mixed reactants.

[0049] To achieve the purpose of stable control of the liquid level in the reactor and a relatively high purity of the reaction products, different PID controls need to be performed on the feed valves of the liquid reactants and the gas reactants. The liquid level in the reactor is mainly affected by the feed flow rate of the liquid reactants. In this application, the purpose of stable liquid level control is achieved by controlling the feed valve of the liquid reactants, and the purpose of improving the purity of the reaction products is achieved by ensuring the proportional entry of the gas reactants by controlling the feed valve of the gas reactants.

[0050] The following specifically describes the specific scheme of a liquid level control method for a gas-liquid two-phase continuous flow reactor provided by this application in conjunction with the attached drawings.

[0051] As Figure 2As shown, it shows a step flow chart of a liquid level control method for a gas-liquid two-phase continuous flow reactor provided by an embodiment of the present application. The method includes the following steps:

[0052] Step S1, obtain the liquid level data, pressure data, loop current of the magnetic stirrer, and feed flow rates of the liquid reactant and the gas reactant of the gas-liquid two-phase continuous flow reactor in real time, and obtain the ideal liquid level, ideal pressure, and ideal loop current of the magnetic stirrer of the gas-liquid two-phase continuous flow reactor.

[0053] Install a liquid level sensor on the side wall of the gas-liquid two-phase continuous flow reactor to obtain the liquid level data of the gas-liquid two-phase continuous flow reactor in real time; install a pressure sensor on the side wall of the gas-liquid two-phase continuous flow reactor to obtain the pressure data of the gas-liquid two-phase continuous flow reactor in real time; install a flow meter at the liquid reactant feed port of the gas-liquid two-phase continuous flow reactor to obtain the feed flow rate of the liquid reactant of the gas-liquid two-phase continuous flow reactor in real time; install a gas flow meter at the gas reactant feed port of the gas-liquid two-phase continuous flow reactor to obtain the feed flow rate of the gas reactant of the gas-liquid two-phase continuous flow reactor in real time; install a current sensor on the power line of the magnetic stirrer to obtain the loop current of the magnetic stirrer in real time.

[0054] In this embodiment, the collection frequencies of the liquid level data, pressure data, loop current, feed flow rate of the liquid reactant, and feed flow rate of the gas reactant are all collected once every 3 seconds. The value of the collection frequency is preset manually, and the implementer can set it by himself. The present application does not make special restrictions.

[0055] Under ideal conditions, the liquid level in the reactor should be at the feed port, and the gas and liquid reactants can be fully mixed. At the same time, under the action of the upward and downward stirring paddles, the fluctuation of the liquid level in the reactor is small at this time. Therefore, the liquid level at the feed port in the reactor is used as the ideal liquid level. The pressure in the reactor under the ideal liquid level is used as the ideal pressure, and the loop current of the magnetic stirrer under the ideal liquid level is used as the ideal loop current.

[0056] Step S2, obtain the liquid level stability value of the reactor at the current moment based on the distribution of all liquid level data within a preset time period adjacent to the current moment, and the difference between the liquid level data and the ideal liquid level.

[0057] Due to the special stirring structure of the gas-liquid two-phase continuous flow reactor, when the liquid level is higher than the ideal liquid level, the liquid level exceeds the gaseous reactant inlet, resulting in the mixed reactants being in a flooding state. The bubbles rise and break and gradually disperse under the shearing action of the stirring paddle, disturbing the liquid surface and causing an increase in instantaneous small fluctuations in the liquid level data. The degree of dispersion of each liquid level data and the liquid level data at multiple adjacent moments is denoted as the adjacent dispersion degree of each liquid level data, which is used to reflect the instantaneous fluctuation of the liquid level data.

[0058] In this embodiment, the number of adjacent moments is 4. The number of adjacent moments can be set by the implementer himself / herself, and this application does not make special restrictions.

[0059] In this embodiment, the degree of dispersion of each liquid level data and its multiple adjacent liquid level data is the coefficient of variation. As other implementation manners, on the basis of being able to measure the uneven distribution degree of the liquid level data, the implementer can use other existing technologies for measurement, such as variance, standard deviation, etc., and this application does not make special restrictions.

[0060] When the liquid level in the reactor is lower than the ideal liquid level, under the action of the upward stirring paddle, the liquid level data fluctuates greatly on a relatively long time scale. All the liquid level data within the preset time period adjacent to the current moment are arranged according to the data size to form a liquid level data sequence, and the liquid level data sequence is equally divided into a preset number of subsequences. Due to the action of multiple stirring paddles in the reactor, the lower the liquid level, the greater the fluctuation amplitude of the obtained liquid level data, and the greater the difference between the average value of the liquid level data in each subsequence and the ideal liquid level. In addition, considering the aggravating effect of gaseous reactants on the local area fluctuation of the liquid level in the gas-liquid two-phase reaction, the lower the liquid level, the stronger the liquid level fluctuation degree, and the greater the degree of dispersion of all the liquid level data in each subsequence.

[0061] In this embodiment, all the liquid level data within the preset time period adjacent to the current moment are arranged in ascending order to form a liquid level data sequence.

[0062] In another embodiment, all the liquid level data within the preset time period adjacent to the current moment are arranged in descending order to form a liquid level data sequence.

[0063] In this embodiment, the preset time period is before the current moment, the length of the preset time period is 2 min, the value of the preset number is 4, and both the length of the preset time period and the value of the preset number are preset artificially and can be set by the implementer himself / herself, and this application does not make special restrictions.

[0064] In this embodiment, the degree of dispersion of all liquid level data within each subsequence is the coefficient of variation. As other implementation manners, on the basis of being able to measure the uneven degree of distribution of the liquid level data within each subsequence, implementers can use other existing technologies for measurement, such as variance, standard deviation, etc., and this application does not make special restrictions.

[0065] Based on the degree of near-neighbor dispersion of each liquid level data within the liquid level data sequence, and the degree of dispersion of all liquid level data within each subsequence, and combining the difference between each liquid level data within each subsequence and the ideal liquid level, obtain the liquid level stability value of the reactor at the current moment. The expression is:

[0066] In the formula, S represents the liquid level stability value of the reactor at the current moment; exp() represents the exponential function with the natural constant as the base, which is used to map to a positive number; C represents the sum of the degrees of near-neighbor dispersion of all liquid level data within the liquid level data sequence, reflecting the small fluctuations of the liquid level data; L represents the number of subsequences; σ i 、 respectively represent the degree of dispersion and the mean value of all liquid level data within the i-th subsequence; h 0 represents the ideal liquid level of the reactor.

[0067] It should be noted that: the more small fluctuations there are in the liquid level data instantaneously, the greater the sum of the degrees of near-neighbor dispersion of all liquid level data within the liquid level data sequence, and the smaller the obtained liquid level stability value; the more the mean value of all liquid level data within each subsequence differs from the ideal liquid level, the greater the amplitude of the fluctuations caused by the action of the stirring paddle on the liquid level, and at the same time, the fluctuations are exacerbated by the influence of gaseous reactants, and the smaller the obtained liquid level stability value. By analyzing the influence of the stirring structure of the reactor on the degree of liquid level fluctuation, the deviation degree of the liquid level in the reactor relative to the ideal liquid level is reflected, the influence of large errors in individual liquid level data is reduced, the accuracy of the subsequent estimation of the current liquid level deviation is improved, and thus the liquid level control effect is enhanced.

[0068] Step S3, based on the liquid level stability value, combine the degree of deviation of the liquid level data from the ideal liquid level, the degree of deviation of the pressure data from the ideal pressure, and the degree of deviation of the loop current from the ideal loop current at the current moment, and obtain the liquid level deviation value of the reactor at the current moment.

[0069] Due to the stirring effect of the magnetic stirrer in the gas-liquid two-phase continuous flow reactor and the violent flow of the reactants in the gas-liquid two-phase state, there are large fluctuations in the liquid level in the reactor, and there is a large error between the obtained liquid level data and the actual liquid level in the reactor. The magnetic stirrer keeps the rotation speed of the stirring paddle constant through feedback control. The higher the liquid level, the greater the resistance on the stirring paddle, and the greater the loop current corresponding to the magnetic stirrer. Therefore, the loop current can be used as one of the feedback control factors for the reactor liquid level. In addition, in the gas-liquid two-phase reaction, the gaseous reactants and liquid reactants enter the reactor proportionally. The lower the liquid level, the less the liquid reactants, the less the corresponding gaseous reactants, and at the same time, the gas volume in the reactor increases and the pressure in the reactor decreases. Therefore, the pressure data can be used as one of the feedback control factors for the reactor liquid level.

[0070] Denote the difference between the liquid level data and the ideal liquid level as the liquid level data difference, the difference between the pressure data and the ideal pressure as the pressure data difference, the difference between the loop current and the ideal loop current as the loop current difference, and use the liquid level data difference, pressure data difference, and loop current difference as components to construct a liquid level deviation vector to reflect the deviation between the liquid level in the reactor and the ideal liquid level.

[0071] Based on the above analysis, according to the correlation between the loop current of the magnetic stirrer, the pressure data and the liquid level data of the reactor, analyze the deviation between the actual liquid level and the ideal liquid level, reduce the influence of the eddy current of the mixed reactants on the estimation of the liquid level deviation, so as to improve the accuracy of the estimation of the liquid level deviation, and further improve the accuracy of the subsequent liquid level control.

[0072] Based on the stable value of the liquid level of the reactor and the liquid level deviation vector at the current moment, obtain the liquid level deviation value of the reactor at the current moment. The expression is:

[0073] In the formula, E represents the liquid level deviation value of the reactor at the current moment; A represents the modulus of the liquid level deviation vector at the current moment; S represents the stable value of the liquid level of the reactor at the current moment; f represents the difference between the liquid level data at the current moment and the ideal liquid level. Among them, the purpose of keeping the positive and negative of the liquid level deviation value consistent with the liquid level data difference is to ensure that the liquid level in the reactor is maintained at the ideal liquid level during the subsequent liquid level control process.

[0074] It should be noted that: the stable value of the liquid level reflects the fluctuation degree of the current liquid level and at the same time reflects the gap between the liquid level and the ideal liquid level. The smaller the stable value of the liquid level, the greater the gap between the liquid level in the reactor and the ideal liquid level; the larger the modulus of the liquid level deviation vector, the greater the deviation amount of the liquid level in the reactor reflected by the liquid level data, pressure data and loop current of the reactor at the current moment.

[0075] Step S4: Preset multiple parameter vectors of the PID control algorithm. Based on the pressure data at the current moment, the feed flow rates of the liquid reactant and the gaseous reactant, and the average level of the liquid level data within the preset time period, and in combination with the parameters of the stirring paddle, the electrical parameters of the magnetic stirrer, the viscosity and elastic coefficient of the gas-liquid two-phase mixed reactant, model the flow field of the gas-liquid two-phase mixed reactant and the magnetic stirrer. Evaluate the control effects of each parameter vector based on the obtained model to obtain the fitness of each parameter vector.

[0076] In this embodiment, the valve opening of the feed port of the liquid reactant is controlled by the PID control algorithm, so as to achieve the purpose of stabilizing the liquid level in the reactor at the ideal liquid level. Randomly select three random numbers W times within the open interval (0, 100), and sequentially use the three randomly selected numbers each time as the proportional parameter, integral parameter, and derivative parameter of the PID control algorithm, and form W parameter vectors. Take the liquid level deviation value as the input of the PID control algorithm and output the valve opening of the feed port of the liquid reactant.

[0077] In this embodiment, the value of W is 30, and the value of W is preset manually. The implementer can set it by himself, and this application does not make special restrictions.

[0078] Considering the complex changes in the flow field of the gas-liquid two-phase mixed reactant due to the change of the reactant flow rate, the particle swarm optimization algorithm is used to tune the control parameters of the PID control algorithm. Take the W parameter vectors as the initial population of the particle swarm optimization algorithm. To evaluate the control effect of any parameter vector on the liquid level of the reactor, use a model simulation platform to model the flow field of the gas-liquid two-phase mixed reactant and the magnetic stirrer in the reactor. The specific process is as follows:

[0079] Take the mean value of all liquid level data in the liquid level data sequence as the reference liquid level of the reactor at the current moment. According to the reference liquid level, pressure data, feed flow rate of the liquid reactant, feed flow rate of the gaseous reactant, parameters of the stirring paddle in the reactor, and the viscosity and elastic coefficient of the gas-liquid two-phase mixed reactant at the current moment, use the VOF (Volume of Fluid) model as the flow field model of the gas-liquid two-phase mixed reactant, and use Ansys-Fluent software to simulate the flow field of the gas-liquid two-phase mixed reactant in the reactor, and output the liquid level data, pressure data, and the fluid resistance received by the stirring paddle. Among them, when simulating the flow field of the gas-liquid two-phase mixed reactant in the reactor, the turbulence model uses the delayed detached eddy simulation (DDES) model, the grid unit uses hexahedral grids, and the specific establishment processes of the VOF model and the DDES model are well-known technologies to those skilled in the art, and this application will not elaborate; the method for obtaining the viscosity and elastic coefficient of the gas-liquid two-phase mixed reactant is a well-known technology, and this application will not elaborate; among them, the parameters of the stirring paddle include: the blade diameter, blade angle, and layer spacing of the stirring paddle.

[0080] According to the fluid resistance received by the stirring paddle and the electrical parameters of the magnetic stirrer, an electrical simulation model of the magnetic stirrer is built using Simulink to output the loop current of the magnetic stirrer. Among them, the specific establishment process of the electrical simulation model is well-known technology to those skilled in the art and will not be elaborated in this application. Among them, the electrical parameters of the magnetic stirrer include: the number of motor pole pairs, slip ratio, and electrical time constant of the magnetic stirrer.

[0081] Perform a step response test on the flow field model and electrical simulation model of the gas-liquid two-phase mixed reactant to obtain the liquid level data, pressure data, and loop current under the step response test, calculate the liquid level deviation value under the control of any parameter vector, and then obtain the calculation result of the integral of time multiplied by absolute error (ITAE) of the liquid level deviation value. Use the calculation result as the fitness of any parameter vector to reflect the control effect of any parameter vector on the liquid level in the reactor.

[0082] Step S5, iteratively obtain the optimal parameter vector at the current moment using an intelligent optimization algorithm based on the multiple parameter vectors. Among them, based on the closeness between the fitnesses of the parameter vectors and the distance between the parameter vectors at each iteration, obtain the convergence factor adjustment rate at each iteration; based on the convergence factor adjustment rate at each iteration, combine with the preset minimum convergence factor to obtain the convergence factor at each iteration.

[0083] Based on the closeness between the fitnesses of the parameter vectors and the distance between the parameter vectors at each iteration, obtain the convergence factor adjustment rate at each iteration. The expression is:

[0084] In the formula, R j represents the convergence factor adjustment rate at the j-th iteration; norm() represents the normalization operation; F j,min represents the minimum value among the fitnesses of all parameter vectors at the j-th iteration; W represents the number of parameter vectors in the population of the particle swarm algorithm; D j,w represents the distance between the w-th parameter vector and the parameter vector with the minimum fitness at the j-th iteration; F j,w represents the fitness of the w-th parameter vector at the j-th iteration; ε represents a preset value greater than 0 used to avoid the denominator being 0. The value of ε is preset manually and can be set by the implementer. In this embodiment, the value of ε is 0.01. In this embodiment, the arctangent normalization function is used for the normalization operation.

[0085] In this embodiment, the distance between parameter vectors is the Euclidean distance. As other implementation manners, on the basis of being able to measure the distance between parameter vectors, implementers can use other existing technologies for measurement, such as Manhattan distance, cosine distance, etc., and this application does not make special restrictions.

[0086] Further, based on the convergence factor adjustment rate at each iteration and in combination with the preset minimum convergence factor, the convergence factor at each iteration is obtained, and the expression is:

[0087] In the formula, represents the convergence factor at the j-th iteration; represents the preset minimum convergence factor; δ represents the preset convergence factor adjustment value; R j represents the convergence factor adjustment rate at the j-th iteration. In the particle swarm optimization algorithm, the values of the two learning factors are equal, and the sum of the two learning factors is equal to the convergence factor.

[0088] Since too small a convergence factor will limit the update of the parameter vector velocity, reduce the moving range of the parameter vector in the search space, and lead to a decline in the global search ability of the algorithm and an inability to explore a better solution space, the value of the preset minimum convergence factor should not be too small. In this embodiment, the value of the preset minimum convergence factor is 4; since when the change of the convergence factor is too large, it may lead to too large an update amplitude of the parameter vector velocity, so that the parameter vector moves too fast in the search space, easily causing the parameter vector to cross the optimal solution and reducing the search accuracy of the algorithm, and when the change of the convergence factor is too small, it may lead to too small an update amplitude of the parameter vector velocity, so that the parameter vector moves too slowly in the search space and reduces the search efficiency of the algorithm. Therefore, the value of the preset convergence factor adjustment value should not be too large or too small. In this embodiment, the value of the preset convergence factor adjustment value is 4; the values of the preset minimum convergence factor and the preset convergence factor adjustment value are both preset manually, and implementers can set them according to the actual situation, and this application does not make special restrictions.

[0089] In this embodiment, the maximum number of iterations of the particle swarm optimization algorithm is 100. The maximum number of iterations of the particle swarm optimization algorithm is preset manually, and implementers can set it by themselves, and this application does not make special restrictions.

[0090] It should be noted that: the larger the liquid level deviation value at the current moment, the greater the gap between the liquid level in the reactor and the ideal liquid level, the greater the degree of adjustment of the valve, the greater the influence of the flow field of the gas-liquid two-phase mixed reactants on the reactant flow rate, and the greater the difficulty in optimizing the optimal parameter vector. The convergence factor is used to reflect the optimization range during each iteration. Therefore, a larger convergence factor is set at the current moment to expand the optimization range and obtain a more accurate liquid level control effect; during the j-th iteration, the larger the minimum value of the fitness of all parameter vectors in the population of the particle swarm algorithm, the worse the control effect of the parameter vector during the j-th iteration, and a larger convergence factor needs to be set to expand the optimization range. And to avoid the particle swarm algorithm falling into a local optimum, the distance D j,w between the remaining parameter vectors in the population and the parameter vector with the minimum fitness during the j-th iteration is j,w the larger, and the fitness difference F j,min the smaller, the larger the convergence factor should be set.

[0091] The process of obtaining the optimal parameter vector at the current moment using the particle swarm algorithm is as follows: taking the initial population as the input of the particle swarm algorithm, and outputting the optimal parameter vector based on the calculated convergence factor and fitness.

[0092] Step S6, using the optimal parameter vector and combining with the PID control algorithm to control the liquid level of the gas-liquid two-phase continuous flow reactor.

[0093] Taking the three components of the optimal parameter vector as the proportional parameter, integral parameter, and differential parameter of the PID control algorithm in sequence, and taking the liquid level deviation value of the reactor at the current moment as the input of the PID control algorithm, and outputting the opening degree of the electric proportional regulating valve at the liquid reactant inlet to achieve stable control of the liquid level of the gas-liquid two-phase continuous flow reactor.

[0094] Figure 3 is the control flow chart of the electric proportional regulating valve at the liquid reactant inlet, Figure 3 where h 0 represents the ideal liquid level of the reactor, p 0 , i 0 respectively represent the ideal pressure in the reactor and the ideal loop current of the magnetic stirrer. p and h respectively represent the pressure data and liquid level data of the reactor at the current moment, i represents the loop current of the magnetic stirrer at the current moment, E represents the liquid level deviation value of the reactor at the current moment; u 1 represents the opening degree of the electric proportional regulating valve at the liquid reactant inlet at the current moment.

[0095] To ensure the purity of the reaction product, the liquid reactant and the gaseous reactant need to be transported into the reactor in proportion, and the purity of the reaction product is ensured by controlling the feed valve of the gaseous reactant. The specific process of PID control for the feed valve of the gaseous reactant is as follows:

[0096] According to the feed flow rate of the liquid reactant, the density and molar mass of the liquid reactant, as well as the density and molar mass of the gaseous reactant at the current moment, calculate the required flow rate of the gaseous reactant at the current moment. The specific calculation method of the required flow rate of the gaseous reactant is well-known technology to those skilled in the art and will not be elaborated in this application.

[0097] Take the difference between the flow rate and the required flow rate of the gaseous reactant at the current moment as the input of the PID control algorithm, and output the opening degree of the electric proportional regulating valve at the feed port of the gaseous reactant. For the PID control algorithm for the electric proportional regulating valve used to control the feed port of the gaseous reactant, the tuning method of the control parameters of the PID control algorithm is the trial-and-error method. The trial-and-error method is well-known technology and will not be elaborated in this application. Figure 4 is the control flow chart of the electric proportional regulating valve at the feed port of the gaseous reactant, Figure 4 where q 0 represents the required flow rate of the gaseous reactant at the current moment, q represents the feed flow rate of the gaseous reactant at the current moment, e represents the difference between the feed flow rate and the required flow rate of the gaseous reactant at the current moment, and the calculation method is e = q - q 0 , u 2 represents the opening degree of the electric proportional regulating valve at the feed port of the gaseous reactant at the current moment.

[0098] In summary, the gas-liquid two-phase continuous flow reactor of this application combines a magnetic stirring reactor and a tubular reactor, successfully integrating the advantageous characteristics of both. Among them, the application of the magnetic stirring method effectively solves the problems of pressure resistance limitation and heat generation due to friction existing in traditional mechanical stirring. And in the gas-liquid two-phase continuous flow reactor, all parts in contact with the reactants are made of c276 Hastelloy material, making the gas-liquid two-phase continuous flow reactor have the performance of corrosion resistance and pressure resistance;

[0099] Furthermore, in terms of liquid level control, deeply analyze the influence mechanism of the reactor stirring structure on the liquid level fluctuation degree, make full use of the correlation between the loop current of the magnetic stirrer, the pressure data of the reactor and the liquid level, accurately obtain the liquid level deviation value, and reduce the influence of the vortex of the gas-liquid two-phase mixed reactants on the liquid level deviation estimation;

[0100] Further, with the aid of a model simulation platform and a particle swarm optimization algorithm, the control parameters of the PID control algorithm are determined more precisely. The liquid level deviation value is combined with the PID control algorithm to control the valve opening degree of the liquid reactant feed port, thereby improving the stability of the liquid level control of the reactor.

[0101] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of code, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the blocks may occur in an order different from that noted in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. In the description corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagram and / or flowchart, as well as combinations of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0102] For those skilled in the art, it is obvious that this application is not limited to the details of the above exemplary embodiments, and without departing from the basic characteristics of this application, this application can be implemented in other specific forms. Therefore, from any point of view, the above embodiments of this application should be regarded as exemplary and non-limiting.

Claims

1. A gas-liquid two-phase continuous flow reactor, characterized in that: The gas-liquid two-phase continuous flow reactor is a new type of continuous flow reaction device which is a combination of a magnetic stirring reactor and a tubular reactor. All parts in contact with reactants in the gas-liquid two-phase continuous flow reactor are made of C276 Hastelloy. There is a magnetic stirrer in the gas-liquid two-phase continuous flow reactor. The reactants in the gas-liquid two-phase continuous flow reactor include liquid reactants and gaseous reactants, among which the mixed reactants of liquid reactants and gaseous reactants in the reaction process are called gas-liquid two-phase mixed reactants.

2. A gas-liquid two-phase continuous flow reactor as claimed in claim 1, characterized in that: There are multiple layers of stirring paddles in the gas-liquid two-phase continuous flow reactor, wherein the stirring paddle on the upper side of the feed inlet is a push-down type, and the stirring paddle on the lower side of the feed inlet is an push-up type, and a static mixer is arranged in the tubular reactor.

3. A liquid level control method for a gas-liquid two-phase continuous flow reactor, applied to a gas-liquid two-phase continuous flow reactor in claim 1, characterized in that: The method comprises the following steps: Real-time acquisition of liquid level data, pressure data, loop current of a magnetic stirrer, and feed flow rates of liquid reactants and gaseous reactants of a gas-liquid two-phase continuous flow reactor, and the ideal liquid level, ideal pressure of the gas-liquid two-phase continuous flow reactor and the ideal loop current of a magnetic stirrer; Based on the distribution of all liquid level data in a preset time period adjacent to the current moment, and the difference between the liquid level data and the ideal liquid level, the liquid level stability value of the reactor at the current moment is obtained; Based on the liquid level stability value, combined with the degree of deviation of the liquid level data from the ideal liquid level, the degree of deviation of the pressure data from the ideal pressure, and the degree of deviation of the loop current from the ideal loop current, the liquid level deviation value of the reactor at the current moment is obtained; Preset multiple parameter vectors of the PID control algorithm, based on the current pressure data, the feed flow rates of the liquid reactants and the gaseous reactants, and the average level of the liquid level data within the preset time period, and in combination with the parameters of the stirring paddle, the electrical parameters of the magnetic stirrer, the viscosity and elastic coefficient of the gas-liquid two-phase mixed reactant, model the flow field of the gas-liquid two-phase mixed reactant and the magnetic stirrer, evaluate the control effect of each parameter vector based on the obtained model, and obtain the fitness of each parameter vector; Iteratively obtaining the optimal parameter vector at the current moment using an intelligent optimization algorithm based on the multiple parameter vectors, wherein the convergence factor adjustment rate at each iteration is obtained based on the closeness between the fitness of the parameter vectors at each iteration and the distance between the parameter vectors; Based on the convergence factor adjustment rate at each iteration and in combination with the preset minimum convergence factor, the convergence factor at each iteration is obtained; The optimal parameter vector is used in combination with a PID control algorithm to control the liquid level of a gas-liquid two-phase continuous flow reactor.

4. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The process of obtaining the liquid level stability value is as follows: The discrete degree of each liquid level data and its multiple neighboring liquid level data at the same time is recorded as the neighboring discrete degree of each liquid level data; All liquid level data within a preset time period adjacent to the current moment are combined into a liquid level data sequence, and the liquid level data sequence is equally divided into a preset number of subsequences; The expression of the liquid level stability value of the reactor at the current moment is: Where S represents the liquid level stability value of the reactor at the current moment; exp() represents an exponential function with a natural constant as the base; C represents the sum of the nearest discrete degrees of all liquid level data in the liquid level data sequence; L represents the number of subsequences; σ i , They represent the discrete degree and mean value of all liquid level data in the i-th subsequence respectively; h0 represents the ideal liquid level of the reactor.

5. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The process of obtaining the liquid level deviation value is as follows: The difference between the liquid level data and the ideal liquid level, the difference between the pressure data and the ideal pressure, and the difference between the loop current and the ideal loop current are used to form a liquid level deviation vector; The expression of the liquid level deviation value of the reactor at the current moment is: Wherein, E represents the liquid level deviation value of the reactor at the current moment; A represents the modulus of the liquid level deviation vector at the current moment; S represents the liquid level stability value of the reactor at the current moment; and f represents the difference between the liquid level data at the current moment and the ideal liquid level.

6. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The fitness is obtained by: obtaining the liquid level deviation value under the control of each parameter vector based on the obtained model, and multiplying the time of the liquid level deviation value under the control of each parameter vector by the calculation result of the absolute error integral index as the fitness of each parameter vector.

7. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The expression of the convergence factor adjustment rate is: In the formula, R j represents the convergence factor adjustment rate at the jth iteration; norm() represents the normalization operation; F j,min represents the minimum value of the fitness of all parameter vectors at the jth iteration; W represents the number of parameter vectors in the population of the particle swarm algorithm; D j,w represents the distance between the wth parameter vector and the parameter vector with the minimum fitness at the jth iteration; F j,w represents the fitness of the wth parameter vector at the jth iteration; ε represents a preset value greater than 0.

8. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The process of obtaining the convergence factor is as follows: Calculate the product of the convergence factor adjustment rate and the preset convergence factor adjustment value at each iteration; The convergence factor is the sum of the product and a preset minimum convergence factor.

9. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The method for controlling the liquid level of the gas-liquid two-phase continuous flow reactor is as follows: the three components in the optimal parameter vector are used as the proportional parameter, integral parameter and differential parameter of the PID control algorithm respectively, the liquid level deviation value of the reactor at the current moment is used as the input of the PID control algorithm, the opening of the valve of the liquid reactant feed port is output, and the liquid level of the gas-liquid two-phase continuous flow reactor is controlled.

10. The liquid level control method of a gas-liquid two-phase continuous flow reactor according to claim 3, characterized in that: The method for controlling the feed flow rate of the gaseous reactant while controlling the liquid level of the gas-liquid two-phase continuous flow reactor is: Based on the feed flow rate of the liquid reactant at the current moment, the required flow rate of the gaseous reactant at the current moment is calculated, and the difference between the feed flow rate of the gaseous reactant at the current moment and the required flow rate is used as the input of the PID control algorithm, and the opening of the valve of the gaseous reactant feed port is output to control the feed flow rate of the gaseous reactant.

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