Rectification column equilibrium parameter estimation method, device and storage medium

Abstract

The application relates to a distillation column equilibrium state parameter estimation method, equipment and a storage medium. The distillation column equilibrium state parameter estimation method comprises the following steps: obtaining distillation column production cumulative data, estimating the feed data equilibrium state parameter of the distillation column according to a pre-determined integral time; and / or collecting current bottom heating steam data and bottom production data, estimating the reflux data equilibrium state parameter of the distillation column according to a pre-determined reflux equilibrium state linear model and the correlation parameter of the reflux equilibrium state linear model. The application effectively improves the distillation column equilibrium state parameter estimation precision, and then the accurate control of the distillation column liquid level can be realized.

Description

Technical Field

[0001] This application relates to the field of industrial intelligent control, and in particular to binary distillation column systems. In industrial scenarios with variable loads and multiple disturbances, this application provides a method, equipment, and storage medium for estimating the equilibrium parameters of a distillation column to achieve precise control of the liquid level. Background Technology

[0002] Distillation columns are widely used for the separation of chemical products; binary distillation columns are used to separate mixtures of two chemical products, obtaining the separated chemical products at the top and / or bottom of the column. The goal of distillation column operation is to achieve continuous production with high load and low energy consumption while meeting product separation quality requirements. Equilibrium parameters refer to a specific set of process parameters determined when the distillation column is operating stably, including feed rate, output rate, reflux rate, input heat, and cooling capacity.

[0003] Theoretically, within the production load range of a distillation column, there can be multiple, or an infinite number, equilibrium states. However, because the reflux tank and reboiler in a distillation column system can retain liquid and have buffering capacity, the distillation column may not be in equilibrium during short-term operation. But from a long-term time-averaged perspective, the various parameters of the distillation column still need to meet the equilibrium requirements.

[0004] Secondly, the distillation column is located in the middle of the production process and is constrained by other upstream and downstream units, so its production load (i.e., the amount of mixed product processed) is often fluctuating. Therefore, fluctuations in production load are unavoidable. Under fluctuating production load conditions, its equilibrium parameters also fluctuate, creating multiple disturbances. This makes the design of the distillation column controller more challenging, and the estimation of equilibrium parameters becomes difficult yet crucial for achieving effective control.

[0005] The present invention aims to solve the problem of accurately estimating the equilibrium parameters of a distillation column under variable load disturbance, thereby achieving distillation column level control. Summary of the Invention

[0006] To address the aforementioned technical problems or at least partially improve the estimation accuracy of equilibrium parameters in distillation columns, this application provides a method, apparatus, and storage medium for estimating equilibrium parameters in distillation columns.

[0007] Firstly, this application provides a method for estimating equilibrium parameters of a distillation column, the method comprising:

[0008] Acquire cumulative outflow data of the distillation column, and estimate the feed data equilibrium parameters of the distillation column according to a predetermined integration time; the cumulative outflow data includes cumulative data of bottom outflow data and top outflow data; the feed data equilibrium parameters are used to control the bottom liquid level of the distillation column; and / or,

[0009] Collect current bottom heating steam data and bottom product data, and estimate the reflux data equilibrium parameters of the distillation column according to a pre-determined reflux equilibrium linear model and the correlation parameters of the reflux equilibrium linear model; the reflux data equilibrium parameters are used to control the reflux tank level and the bottom liquid level of the distillation column.

[0010] Optionally, the method for estimating the equilibrium parameters of the distillation column further includes:

[0011] Obtain the maximum lag time of the liquid level control and the control time of the distillation column controller;

[0012] Compare the maximum lag time of the level control with the control time of the distillation column controller.

[0013] The integration time is determined based on the numerical value.

[0014] Alternatively, the equilibrium parameter F0 of the feed data for the distillation column can be estimated according to the following formula:

[0015]

[0016] In the formula, t is the integration time, D is the data collected at the top of the tower, and B is the data collected at the bottom of the tower.

[0017] Optionally, before estimating the equilibrium parameters of the distillation column's reflux data, the following steps are also included:

[0018] Estimated initial parameters of the distillation column in reflux equilibrium state;

[0019] Based on the equilibrium parameters of the feed data and the initial parameters of the reflux equilibrium state, the distillation column level controller is started.

[0020] Optionally, the correlation parameters of the reflux equilibrium linear model are determined as follows:

[0021] Collect operational sample data of the distillation column; the operational sample data includes reflux data, bottom heating steam data, and bottom product data;

[0022] The correlation parameters are obtained by correlating the pre-determined reflux equilibrium state model with the operational sample data.

[0023] The linear model for the reflux equilibrium state is as follows:

[0024] R = K1 * Fv - K2B - C

[0025] In the formula, R is the reflux flow rate, K1 is the proportionality coefficient of the bottom heating steam data, K2 is the proportionality coefficient of the bottom output data, and C is a constant.

[0026] Optionally, the initial parameters of the reflux equilibrium state are estimated using the following method:

[0027] The distillation column was tested according to the predetermined equilibrium evaluation criteria to obtain test sample data;

[0028] Based on the experimental sample data, a linear correlation between the bottom heating steam data and the reflux data was determined;

[0029] Based on the linear correlation between the bottom heating steam data and the reflux data, the initial parameters of the reflux equilibrium state are estimated.

[0030] Optionally, the method for estimating the equilibrium parameters of the distillation column further includes:

[0031] Based on the material conservation relationships among the medium, reflux data, and top-collected data; the proportional relationships between the bottom-collected data and top-collected data; the proportional relationships between the latent heat of vaporization of the bottom-heating steam and the latent heat of vaporization of the medium; the temperature difference between the feed temperature and the bottom-collected temperature; the proportional relationships between the heat capacity of the medium and the latent heat of vaporization of the medium; and the proportional relationships between the bottom-collected data and the top-collected data, the heat balance relationship among the reflux data, top-collected data, and bottom-collected data is simplified to obtain an initial model of the reflux equilibrium state.

[0032] Based on the proportional relationship between the bottom and top data of the tower, the initial model of the reflux equilibrium state is simplified to obtain the linear correlation between the bottom heating steam data and the reflux data.

[0033] Optionally, the equilibrium state assessment criterion includes: if the reflux tank level remains unchanged under any values ​​of bottom heating steam data and top extraction data, then the reflux tank level is in equilibrium.

[0034] In a second aspect, this application provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor;

[0035] When the computer program is executed by the processor, it implements the steps of the distillation column equilibrium parameter estimation method as described in any of the preceding claims.

[0036] Thirdly, this application provides a computer-readable storage medium storing a distillation column equilibrium parameter estimation program.

[0037] When the distillation column equilibrium parameter estimation program is executed by the processor, it implements the steps of the distillation column equilibrium parameter estimation method as described in any of the preceding items.

[0038] The technical solution provided in this application has the following advantages compared with the prior art:

[0039] This application estimates the equilibrium parameters of the distillation column by acquiring the cumulative output data of the distillation column and, according to a predetermined integration time; and / or, by acquiring the current bottom heating steam data and bottom output data, and, according to a predetermined reflux equilibrium linear model and the correlation parameters of the reflux equilibrium linear model, estimates the reflux equilibrium parameters of the distillation column, thereby effectively improving the estimation accuracy of the equilibrium parameters of the distillation column and enabling precise control of the distillation column liquid level. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart of the distillation column equilibrium parameter estimation method in various embodiments of this application;

[0043] Figure 2 These are schematic diagrams of typical binary distillation column structures in various embodiments of this application;

[0044] Figure 3 This is a schematic diagram illustrating the changes of the sampled flow rates D and B over time in various embodiments of this application;

[0045] Figure 4 This is a schematic diagram illustrating the equilibrium state characteristics of the reflux R in various embodiments of this application. Specific Implementation

[0046] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0047] In the following description, the use of suffixes such as "module," "component," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "component," or "unit" may be used interchangeably. Terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. Terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] Example 1

[0049] This invention provides a method for estimating equilibrium parameters of a distillation column, such as... Figure 1 As shown, the method for estimating the equilibrium parameters of the distillation column includes:

[0050] S101, acquire the cumulative outflow data of the distillation column, and estimate the feed data equilibrium parameters of the distillation column according to a predetermined integration time; the cumulative outflow data includes the cumulative data of the bottom outflow data and the top outflow data; the feed data equilibrium parameters are used to control the bottom liquid level of the distillation column; and / or,

[0051] S102, collect the current bottom heating steam data and bottom output data of the distillation column, and estimate the reflux data equilibrium parameters of the distillation column according to the predetermined reflux equilibrium linear model and the correlation parameters of the reflux equilibrium linear model; the reflux data equilibrium parameters are used to control the reflux tank level and the bottom liquid level of the distillation column.

[0052] In industrial scenarios with varying loads and multiple disturbances, maintaining precise control of the distillation column level, including the levels in the reflux tank and the reboiler, is not only necessary for continuous production but also often crucial for achieving high separation quality over the long term. However, due to various disturbances such as fluctuations in reboiler heating, feed, reflux, and ambient temperature, achieving precise control of the distillation column level is quite challenging.

[0053] This invention improves the accuracy of distillation column equilibrium parameter estimation by acquiring cumulative outflow data from the distillation column and estimating the feed data equilibrium parameters of the distillation column according to a predetermined integration time; and / or, by acquiring current bottom heating steam data and bottom outflow data, estimating the reflux data equilibrium parameters of the distillation column according to a predetermined reflux equilibrium linear model and the correlation parameters of the reflux equilibrium linear model, thereby achieving precise control of the distillation column liquid level.

[0054] The significance of estimating the equilibrium parameters of the feed data and reflux data in this embodiment of the invention lies in the fact that the distillation column controller (LIC) maintains the liquid levels in the column bottom and reflux tank by manipulating the feed and reflux data. From the perspective of time averaging, the ultimate goal of the LIC is to control the feed data to tend towards its equilibrium parameters and the reflux data to tend towards its equilibrium parameters.

[0055] Since the downstream top and bottom feed data are changing, which means that the production load is changing, this embodiment of the invention enables the controller to adapt to the production load of the distillation column by correctly estimating the equilibrium parameters of the feed data.

[0056] Due to the heat balance of the distillation column, this embodiment of the invention, based on the current bottom heating steam data and bottom product data, and according to a pre-determined reflux equilibrium linear model and its correlation parameters, shows that the reflux data equilibrium parameters are primarily affected by the bottom heating steam data. Furthermore, lower bottom heating steam data corresponds to lower reflux data equilibrium parameters. Therefore, when the reflux data equilibrium parameters can satisfy the effective control of the LIC controller, the bottom heating steam data can be reduced as much as possible until it reaches the lower limit, effectively achieving energy savings. In the industrial application of this embodiment, on the one hand, the LIC achieves automated operation of the distillation column; on the other hand, by reducing the bottom heating steam data, a 6% energy saving is achieved.

[0057] Based on the main concepts of the embodiments of the present invention described above, the following specific embodiment will be used to describe in detail the optional implementation methods of the embodiments of the present invention. These optional implementation methods can be arbitrarily combined without contradiction to obtain new technical solutions.

[0058] like Figure 2 As shown, the parameters of the distillation column are as follows: feed rate (feed data) is F, bottom product rate (bottom product data) is B, top product rate (top product data) is D, reflux rate (reflux data) is R, bottom heating steam rate (bottom heating steam data) is Fv, top cooling rate (top cooling data) is Qc, and V is the medium, which varies depending on the product; the reflux tank level is Ld, and the bottom liquid level is Lb. In this embodiment, it is assumed that Qc can be supplied infinitely and adapts to Fv, therefore it does not need to be specially considered.

[0059] Liquid level control: In this embodiment, the distillation column controller adopts multiple-input multiple-output (MIMO) control, defined as LIC. It uses F, R, and Fv as control means (inputs) and simultaneously controls Lb and Ld (outputs). The goal is to maintain Lb and Ld within the corresponding preset liquid level data range, that is, to keep them within a certain parameter range or to track a specific set value.

[0060] 1. Estimation of feed rate F equilibrium parameters (feed data equilibrium parameters)

[0061] Obtain the cumulative output data of the distillation column, and estimate the equilibrium parameters of the feed data of the distillation column according to the predetermined integration time.

[0062] In detail, since a distillation column is a continuous system, its long-term operation must comply with the constraint of mass conservation, and therefore the following conservation relationship exists:

[0063] F0 = D0 + B0 (Equation 1)

[0064] In actual production, D and B are determined by the downstream production load, such as Figure 3 As shown, the flow rate is constantly changing. To maintain Equation 1, an integral method is needed to obtain the true cumulative flow rate (i.e., the cumulative data of the distillation column's output). The integral relationship between the feed data, bottom output data, and top output data is as follows:

[0065]

[0066] Where the upper and lower limits of integration, 0, represent any starting point at time, and t refers to a time period, the specific value of which is determined by the following rules:

[0067] A) Assume the maximum lag time of level control is T. delay This refers to the process where, when controlling the liquid level via control signals F or R, at least T must pass through the system. delay Only then can its liquid level control effect be displayed;

[0068] B) Assume the adoption period of the LIC controller is T. control If m control steps are required for the controlled variable Lb or Ld to reach the set value, then the total control time for one set-control cycle (i.e., the control time of the distillation column controller) is T. control ×m.

[0069] C) The integral time is then defined as the larger of three times the pure time delay and the total control time, i.e.:

[0070] t = max(3T) delay ,T control ×m) (Equation 3)

[0071] For example, in this embodiment, the maximum pure hysteresis time of the reflux R to the Lb level is 8 minutes, while the sampling time used by the LIC controller is 5 minutes, requiring 5 steps for a single control adjustment. Therefore, the integral time is chosen to be 25 minutes, as shown in the following calculation example:

[0072] t = max(3×8, 5×5) = 25 (Equation 4)

[0073] In other words, in some implementations, the maximum lag time of the level control and the control time of the distillation column controller can be obtained; the values ​​of the maximum lag time of the level control and the control time of the distillation column controller can be compared; and the integral time can be determined based on the values, for example, the time with the larger value can be used as the integral time.

[0074] Based on the relationship between Equations 1 and 2, the final equilibrium parameter F0 is calculated as follows:

[0075]

[0076] As an example, in this embodiment, the LIC controller corrects the equilibrium parameters once every t = 25 minutes.

[0077] 2. Estimation of equilibrium parameters for reflux R

[0078] Estimated initial parameters of the distillation column in reflux equilibrium state;

[0079] Based on the equilibrium parameters of the feed data and the initial parameters of the reflux equilibrium state, the distillation column level controller is started.

[0080] Collect current bottom heating steam data and bottom output data, and estimate the reflux data equilibrium parameters of the distillation column according to the predetermined reflux equilibrium linear model and the correlation parameters of the reflux equilibrium linear model.

[0081] In detail, such as Figure 2 As shown, the reflux R in a distillation column not only affects the liquid levels at the top and bottom of the column, but also plays a role in maintaining the heat balance of the distillation column. The larger the flow rate of the heating steam Fv in the reboiler, the more heat is input into the distillation column. At this time, more cold material is needed to balance this heat, and R must be larger. Therefore, Fv and R are closely related, and their values ​​are roughly proportional.

[0082] Based on the principle of heat conservation, the following equilibrium equation can be defined:

[0083] Fv*Hv=V*Hz+ΔT*Cp*B+Q e (Equation 6)

[0084] The left side of the equation represents the heat released by the condensation of steam in the distillation column using a total condenser heater, which is the input heat of the distillation column. Here, Fv is the steam flow rate and Hv is the latent heat of vaporization of the steam.

[0085] The right side of the equation represents the various effects on the heated medium inside the distillation column. In the first term on the right, V is the flow rate of the medium as it changes from liquid to gas, and Hz is the latent heat of vaporization of the medium. The second term on the right represents the heat removed from the bottom of the column, where B is the bottom discharge rate, Cp is the heat capacity of the medium in its liquid state, and ΔT is the difference between the bottom temperature and the feed temperature. The third term on the right, Q... e This represents the heat lost due to insulation factors such as the outer shell and piping of the distillation column.

[0086] At the top of the column, the total condenser condenses all of V into liquid, which is stored in the reflux tank. A portion of this liquid is returned to the distillation column (R), and the remainder is collected as product (D). Therefore, based on the mass conservation relationship between the medium, reflux data, and top product data:

[0087] V = R + D (Equation 7)

[0088] By combining equations 6 and 7, we can see the heat balance relationship between steam Fv and R, D, and B:

[0089] Fv*Hv=(R+D)*Hz+ΔT*Cp*B+Q e (Equation 8)

[0090] Equation 8 shows that the return flow rate R is related to Fv, D, and B. Even if the steam flow rate remains unchanged, the equilibrium state of R will still be affected by the output D and B.

[0091] Calculating the equilibrium state of R using Equation 8 in practice is still very inconvenient, mainly due to the following difficulties:

[0092] A)Q e While it is impossible to measure, Qe will change as the ambient temperature changes with the seasons can be anticipated.

[0093] B) It is necessary to conduct a large number of experiments with Fv, D, and B as variables to obtain an accurate functional relationship with R. However, conducting a large number of experiments in the factory would result in huge experimental costs, which is not allowed under the actual production conditions of the factory, and therefore cannot be achieved.

[0094] C) There is a lack of criteria for judging the equilibrium state of R. Because Fv, D, and B are usually in a state of fluctuation, and the heat imbalance will only slowly affect the liquid levels Lb and Ld, it is actually difficult to judge whether the distillation column has reached thermal equilibrium;

[0095] For the reasons mentioned above, this embodiment uses the following method to obtain an approximate estimate:

[0096] 1) Equilibrium state evaluation criteria

[0097] Under arbitrary values ​​of bottom heating steam and top extraction steam data, if the reflux tank level remains constant, then the reflux tank level is in equilibrium. Specifically, the reflux tank level Ld is only affected by three streams: rising medium steam V, reflux R, and extraction D, and they conform to the relationship defined in Equation 7. Therefore, under arbitrary values ​​of Fv and D, as long as the Ld level does not change, an equilibrium state can be assessed. Figure 4 As shown, the arrow indicates the curve representing the change of the liquid level Ld at the top of the column over time. The figure shows the locations of the two equilibrium states, and the slope of the curve is close to 0.

[0098] 2) Simplify the heat balance equation 8

[0099] Based on the material conservation relationships among the medium, reflux data, and top-collected data; the proportional relationships between bottom-collected data and top-collected data; the multiple relationship between the latent heat of vaporization of water vapor and the latent heat of vaporization of the medium; the temperature difference between the feed temperature and the bottom-collected temperature; the proportional relationship between the heat capacity of the medium and the latent heat of vaporization of the medium; and the proportional relationship between bottom-collected data and top-collected data, the heat balance relationship among the reflux data, top-collected data, and bottom-collected data is simplified to obtain the initial model of the reflux equilibrium state.

[0100] In detail, based on the actual parameters of this embodiment and the results of thermodynamic calculations, the latent heat of vaporization of water vapor Hv is 5 times that of the latent heat of vaporization of the medium Hz. The temperature difference between the feed temperature and the bottom-collected temperature is 20 degrees Celsius. The heat capacity of the medium is approximately 1 / 500 of its latent heat of vaporization. With a fixed product quality Xf, there is a proportional relationship between the bottom-collected data and the top-collected data; that is, D and B have a definite proportional relationship of approximately:

[0101]

[0102] Based on the above relationships, and combining Equations 7, 8, and 9, according to the material conservation relationships between the medium, reflux data, and top-collected data; the proportional relationships between the bottom-collected data and top-collected data; the proportional relationships between the latent heat of vaporization of the bottom-heating steam and the latent heat of vaporization of the medium; the temperature difference between the feed temperature and the bottom-collected temperature; the proportional relationships between the heat capacity of the medium and the latent heat of vaporization of the medium; and the proportional relationships between the bottom-collected data and the top-collected data, the heat balance relationship between the reflux data, top-collected data, and bottom-collected data can be simplified, and the initial model of the reflux equilibrium state can be obtained:

[0103] R = 5Fv - 0.7BC (Equation 10)

[0104] Furthermore, assuming that the ambient temperature has different values ​​in typical summer or winter, and remains essentially constant, then applying Equation 10 only requires changing two parameters: Fv and B.

[0105] Secondly, Fv corresponds to the production load of the distillation column. That is, under a certain load, there exists a minimum value for Fv; otherwise, the product quality will be substandard. Since the production load can be represented by the feed F or the output D+B, this means that Fv is not completely independent. Combined with Equation 9, Fv and B also have a certain correspondence. In this embodiment, the ratio of Fv to B is approximately 1, that is, B is approximately equal to Fv. Therefore, based on the predetermined ratio between the bottom and top output data, the initial reflux equilibrium model is simplified, and the linear correlation between the bottom heating steam data and the reflux data is obtained. Equation 9 can be further simplified to:

[0106] R = 4.3Fv - C (Equation 11)

[0107] Each simplification step in Equations 9 to 11 results in a loss of some computational accuracy, but the macroscopic relationship remains essentially correct. A more general expression, 12, simplifies the initial reflux equilibrium model based on the proportional relationship between the bottom and top sampling data, obtaining a linear correlation between the bottom heating steam data and the reflux data. It can be seen that the reflux R is approximately proportional to Fv.

[0108] R = K * Fv - C (Equation 12)

[0109] Among them, the proportionality coefficient K and the constant C are determined by limited industrial tests. From this, a preliminary estimate can be obtained to obtain the initial parameters of the reflux equilibrium state.

[0110] 3) Optimal estimation of R0

[0111] Based on Equations 10 and 12, this embodiment uses a two-stage approach to obtain accurate estimates.

[0112] A. In the first stage, the distillation column is tested according to the predetermined equilibrium evaluation criteria to obtain test sample data. Based on the test sample data, the linear correlation between the bottom heating steam data and the reflux data is determined. Based on the linear correlation between the bottom heating steam data and the reflux data, the initial parameters of the reflux equilibrium state are estimated. Specifically, before the controller LIC is initially put into operation, Equation 10 is used for estimation. The specific method is to divide the bottom heating steam data and reflux data into preset quantity levels within the preset adjustable range of the bottom heating steam data and reflux data. According to the settings, the test is conducted. Test sample data is obtained according to the predetermined equilibrium evaluation criteria. For example, within the adjustable range of Fv, Fv is divided into 3 levels; within the adjustable range of the bottom output B, B is divided into 3 levels. An industrial field experiment is conducted, and the aforementioned "equilibrium evaluation criteria" are applied to obtain a local sample. A total of 9 samples are obtained. Then, Equation 12 is used to linearly fit Fv and R to obtain a linear correlation between the bottom heating steam data and the reflux data that comprehensively considers the influence of B. This correlation has proven to be effective in actual operation, ensuring that the LIC controller can function properly.

[0113] B. In the second stage, the distillation column is controlled based on the equilibrium parameters of the feed data and the pre-estimated initial reflux equilibrium parameters. Specifically, the linear correlation between the bottom heating steam data and the reflux data can be determined based on the test sample data; and the initial reflux equilibrium parameters are estimated based on this linear correlation. In other words, the initial equilibrium estimates obtained from Equations 5 and 12 can be applied to put the LIC into operation. At this time, the LIC can control Ld and Lb, but the fluctuations are significant.

[0114] Collect operational sample data for the distillation column; the operational sample data includes reflux data, bottom heating steam data, and bottom product data. Specifically, one operational sample data point is collected every 5 seconds for reflux R, steam Fv, and bottom product B, and all data collected within m minutes after the controller is put into operation is defined as a set U1.

[0115] U1={R i ,Fv i B i} i=1,n (Formula 13)

[0116] In the formula, n represents the total number of samples obtained within m minutes. For example, in 30 minutes, the value of n is 360.

[0117] The correlation parameters are obtained by associating the predetermined initial model of the reflux equilibrium state with the operational sample data U1. Specifically, based on U1, an effective equilibrium operational sample data can be obtained by applying an integral average to R, Fv, and B.

[0118]

[0119] An effective equilibrium state is defined as:

[0120] Since the effective working ranges of R, Fv, and B are known in advance, after a sufficient number of samples are collected, they will be roughly evenly scattered within their respective working ranges, thus forming an equilibrium running sample dataset U2 that can be applied to Equation 10.

[0121]

[0122] Using U2 to perform a linear correlation on Equation 10, we obtain the linear model of the reflux equilibrium state and the relevant correlation parameters in Equation 16:

[0123] R = K1*Fv - K2B - C (Equation 16)

[0124] The correlation parameters include the scaling factor for the bottom heating steam data, the scaling factor for the bottom extracted data, and a constant. In the formula, K1 is the scaling factor for Fv, K2 is the scaling factor for B, and C is a constant.

[0125] Therefore, Equation 16 can be used to collect the current bottom heating steam data and bottom product data. Based on the pre-determined reflux equilibrium linear model and its correlation parameters, the reflux data equilibrium parameters of the distillation column can be estimated, thereby obtaining the equilibrium parameters R0 for any Fv and B. These reflux data equilibrium parameters are used to control the reflux tank level and the bottom liquid level of the distillation column.

[0126] In this embodiment, based on the collected data, an estimate of the feed equilibrium state is obtained at regular intervals using an integral method, and a method for processing the integration time is provided. A two-stage processing scheme is used to estimate the reflux equilibrium state. In the first stage, a simplified univariate linear model is used for preliminary estimation to allow the controller to start. In the second stage, after the controller is put into operation, a more accurate two-variable linear model is obtained by continuously collecting and accumulating industrial data under control conditions.

[0127] The significance of equilibrium parameters F0 and reflux R0: The controller LIC maintains liquid levels Lb and Ld by manipulating F and R. From the perspective of time averaging, the ultimate goal of LIC is to control F to tend towards F0 and R to tend towards R0.

[0128] The correct estimation of F0 in this embodiment of the invention: Since downstream D and B are changing, it means that the production load is changing. A correct estimation of F0 means that the controller can adapt to the production load of the distillation column.

[0129] The correct estimation of R0 in this embodiment of the invention: Due to the heat balance of the distillation column, based on Equation 12, R0 is mainly affected by the steam Fv. A smaller Fv corresponds to a lower R0. Therefore, when R0 can satisfy the effective control of the controller LIC, Fv can be reduced as much as possible until the lower limit of Fv is reached, which will effectively achieve energy saving. In the industrial application of this embodiment, on the one hand, LIC realizes the automated operation of the distillation column; on the other hand, by reducing steam Fv, a 6% energy saving is achieved.

[0130] Example 2

[0131] This invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor;

[0132] When the computer program is executed by the processor, it implements the steps of the distillation column equilibrium parameter estimation method as described in any of the embodiments in Example 1.

[0133] Example 3

[0134] This invention provides a computer-readable storage medium storing a distillation column equilibrium parameter estimation program.

[0135] When the distillation column equilibrium parameter estimation program is executed by the processor, it implements the steps of the distillation column equilibrium parameter estimation method as described in any of the embodiments in Example 1.

[0136] The specific implementations of Embodiments 2 and 3 can be found in Embodiment 1, and they have the corresponding technical effects.

[0137] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0138] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0139] Through the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0140] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for estimating equilibrium parameters of a distillation column, characterized in that, The method for estimating the equilibrium parameters of the distillation column includes: Acquire cumulative outflow data of the distillation column, and estimate the feed data equilibrium parameters of the distillation column according to a predetermined integration time; the cumulative outflow data includes cumulative data of bottom outflow data and top outflow data; the feed data equilibrium parameters are used to control the bottom liquid level of the distillation column; and / or, Collect current bottom heating steam data and bottom product data, and estimate the reflux data equilibrium parameters of the distillation column according to a pre-determined reflux equilibrium linear model and the correlation parameters of the reflux equilibrium linear model. The reflux data equilibrium parameters are the estimated values ​​of reflux data required for the distillation column to be in equilibrium, and are used to control the reflux tank level and the bottom level of the distillation column. The correlation parameters of the reflux equilibrium linear model are determined by collecting operational sample data of the distillation column; the operational sample data includes reflux data, bottom heating steam data, and bottom product data. The correlation parameters are obtained by correlating the pre-determined reflux equilibrium state model with the operational sample data; the correlation parameters include the scaling factor of the bottom heating steam data, the scaling factor of the bottom extracted data, and constants. The linear model for the reflux equilibrium state is as follows: ； In the formula, R is the reflux data, K1 is the proportionality coefficient of the bottom heating steam data, Fv is the bottom heating steam data, K2 is the proportionality coefficient of the bottom sampling data, B is the bottom sampling data, and C is a constant. The equilibrium parameter F0 of the feed data for the distillation column is estimated using the following formula: ； In the formula, t is the integration time, D is the data collected at the top of the tower, and B is the data collected at the bottom of the tower; The method for estimating the equilibrium parameters of the distillation column further includes: Based on the material conservation relationships among the medium, reflux data, and top-collected data; the proportional relationships between the bottom-collected data and top-collected data; the proportional relationships between the latent heat of vaporization of the bottom-heating steam and the latent heat of vaporization of the medium; the temperature difference between the feed temperature and the bottom-collected temperature; the proportional relationships between the heat capacity of the medium and the latent heat of vaporization of the medium; and the proportional relationships between the bottom-collected data and the top-collected data, the heat balance relationship among the reflux data, top-collected data, and bottom-collected data is simplified to obtain an initial model of the reflux equilibrium state. Based on the proportional relationship between the bottom and top data of the tower, the initial model of the reflux equilibrium state is simplified to obtain the linear correlation between the bottom heating steam data and the reflux data.

2. The method for estimating equilibrium parameters of a distillation column according to claim 1, characterized in that, The method for estimating the equilibrium parameters of the distillation column further includes: Obtain the maximum lag time of the liquid level control and the control time of the distillation column controller; Compare the maximum lag time of the level control with the control time of the distillation column controller. The integration time is determined based on the numerical value.

3. The method for estimating equilibrium parameters of a distillation column according to any one of claims 1-2, characterized in that, Before estimating the equilibrium parameters of the distillation column's reflux data, the following steps are also included: Estimated initial parameters of the distillation column at reflux equilibrium; Based on the equilibrium parameters of the feed data and the initial parameters of the reflux equilibrium state, the distillation column level controller is started.

4. The method for estimating equilibrium parameters of a distillation column according to claim 3, characterized in that, The initial parameters of the reflux equilibrium state are estimated using the following method: The distillation column was tested according to the predetermined equilibrium evaluation criteria to obtain test sample data; Based on the experimental sample data, a linear correlation between the bottom heating steam data and the reflux data was determined; Based on the linear correlation between the bottom heating steam data and the reflux data, the initial parameters of the reflux equilibrium state are estimated.

5. The method for estimating equilibrium parameters of a distillation column according to claim 1, characterized in that, The equilibrium state assessment criteria include: if the reflux tank level remains unchanged under any values ​​of bottom heating steam data and top extraction data, then the reflux tank level is in equilibrium.

6. An electronic device, characterized in that, The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor; When the computer program is executed by the processor, it implements the steps of the distillation column equilibrium parameter estimation method as described in any one of claims 1-5.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program for estimating the equilibrium parameters of a distillation column. When the distillation column equilibrium parameter estimation program is executed by the processor, it implements the steps of the distillation column equilibrium parameter estimation method as described in any one of claims 1-5.

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