Adaptive control method and system for a semi-batch apparatus-solvent separation column

Abstract

The application discloses a kind of based on semi-intermittent device-solvent separation tower self-adapting control method and system, it is related to solvent separation technical field, by obtaining the real-time reflux liquid level value of the reflux tank connected with the output end of solvent separation tower, reflux tank is returned to solvent separation and low-boiling-point solvent, cooling is carried out to gaseous distillate, and high-boiling-point solvent in it is liquefied, according to real-time reflux liquid level value and preset formula, the evaporation capacity of column still of solvent separation tower is calculated, and according to the evaporation capacity of column still, the temperature rising rate of column still of solvent separation tower is calculated and controlled, in control process, by integrating artificial operation and historical data experience, the evaporation capacity is characterized by the rising rate of reflux tank liquid level, the best parameters of the rising rate of temperature required in the operation cycle of solvent separation tower and the liquid level change rate of reflux tank are summarized and arranged, overcome the problem that artificial operation cannot real-time analysis and calculation to temperature and liquid level change, control process is fine, stable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solvent separation, in particular to a self-adaptive control method and system based on a semi-batch device-solvent separation column. BACKGROUND

[0002] In the process of traditional chemical production, when some raw materials need to be processed in batches, or the output is small, or the composition of the components changes frequently, batch or semi-batch rectification devices are often used.

[0003] There are many by-products in the pre-separation device of solvent separation, which causes the composition of the components to change frequently, so the semi-batch separation column is used to separate and reuse them. If the products separated by the device are unqualified, the solvent may cause serious quality accidents when it is put into production again; if the processing capacity of the device does not meet the corresponding requirements, the solvent may accumulate, causing the device to stop. Both of the above situations not only cause losses to the enterprise, but also may cause production accidents. Therefore, the self-adaptive control of the solvent separation column is extremely important, which can greatly reduce the risk of enterprise production.

[0004] At present, the control of the solvent separation column mainly observes the boiling situation and temperature of the column kettle of the separation column by using a camera to adjust in stages, and different temperature set values are set in different stages to adjust the steam. When the temperature and liquid level reach a certain value, the feeding and steam are stopped, and then the device is stopped. However, due to the unreasonable setting of the set value of the temperature of the column kettle or the fluctuation of the high waste content in the normal production process, there may be more solvent in the residual liquid, or the temperature rising speed is too fast, which leads to small solvent processing capacity, unqualified products, and large device energy consumption. If the processing capacity does not meet the requirements for a long time, the storage capacity of the solvent tank will increase sharply, and the pre-separation device will be forced to stop, causing significant property losses.

[0005] Therefore, the existing control has the following defects:

[0006] The solvent separation is a non-steady-state semi-batch process, the column kettle is continuously fed but not produced, and as the high-boiling substances in the column kettle continuously accumulate, the temperature required by the solvent column kettle becomes higher; however, the composition of the high-boiling substances is complex and variable, and the high-boiling substance content has a nonlinear relationship with the required rectification temperature, causing the device to be often out of balance. SUMMARY

[0007] The purpose of the present application is to provide a self-adaptive control method and system based on a semi-batch device-solvent separation column, to control the operation mode of the temperature change rate and the liquid level change rate of the column kettle, and to more intuitively display the influence of the high-boiling substances in the column kettle on the required temperature for rectification. When the liquid level rising rate is unreasonable, the temperature change rate can be adjusted according to the formula, achieving the effect of self-adaptive control, and the control process is more delicate and stable.

[0008] To solve the above technical problems, the embodiment of the present application provides a semi-batch device-solvent separation column adaptive control method, comprising:

[0009] S1: obtaining a real-time reflux liquid level value of a reflux tank connected to an output end of a solvent separation column, and returning the cooled solvent in the reflux tank to the solvent separation column, cooling gaseous distillates of the solvent separation column, and liquefying distillates with a boiling point higher than the reflux solvent;

[0010] S2: calculating the column still evaporation amount of the solvent separation column according to the real-time reflux liquid level value and formula (1);

[0011] wherein, (1),

[0012] wherein, F E is the column still evaporation amount, L rt1 is the liquid level value of the reflux tank at the current time, L rt2 is the liquid level value of the reflux tank n minutes ago, R r is the radius of the reflux tank, and ρ1 is the solvent density of the reflux tank;

[0013] S3: controlling the temperature rising rate of the column still of the solvent separation column according to the column still evaporation amount and formula (2), (3), and (4);

[0014] (2);

[0015] (3);

[0016] (4);

[0017] wherein, ΔT is the temperature rising rate calculated according to the column still evaporation amount; F E is the column still evaporation amount; F a is the feed amount of the crude solvent; ω w is the water content in the crude solvent entering the solvent separation column; ω a is the solvent content in the crude solvent; K3 is a heat and temperature conversion coefficient calculated according to historical data and physical properties; ΔT max is the maximum value of the allowed temperature change after the change; ΔT max_t1 is the maximum value of the allowed temperature change after the change at t1; ΔT min is the minimum value of the allowed temperature change after the change; and ΔT min_t1 is the minimum value of the allowed temperature change after the change at t1.

[0018] wherein, after the S3, further comprising:

[0019] S4: judging whether the liquid level of the reflux tank is greater than the production value and not produced;

[0020] If not, S5: opening the production valve of the reflux tank until the production valve is closed after production; if yes, turning to the S2.

[0021] wherein, after the S3, further comprising:

[0022] S6: calculating the steam amount of the column reboiler for heating the solvent separation column according to the current temperature value of the solvent separation column and formula (5);

[0023] (5);

[0024] wherein, F LS is the steam amount; T t1 is the current temperature of the column of the solvent separation column; T t2 is the temperature of the column of the solvent separation column n minutes ago; K1 is the gain of the steam amount and temperature change obtained by modeling according to historical data.

[0025] wherein, after the S3, further comprising:

[0026] S7: calculating the feed amount of the solvent separation column according to the current liquid level value of the solvent separation column and formula (6);

[0027] wherein, (6);

[0028] wherein, F a is the crude solvent feed amount of the solvent separation column; L t1 is the current liquid level value of the column of the solvent separation column; L t1 is the liquid level value of the column of the solvent separation column n minutes ago; ΔL max is the maximum value of the allowed liquid level change; ΔL min is the minimum value of the allowed liquid level change; K2 is the gain of the solvent feed amount and liquid level change obtained by modeling according to historical data.

[0029] wherein, after the S3, further comprising:

[0030] displaying the real-time reflux liquid level value of the reflux tank, the column evaporation amount, the solvent density, the liquid level of the reflux tank, the temperature value of the solvent separation column, the steam amount, the liquid level value of the solvent separation column, and the feed amount of the solvent separation column.

[0031] wherein, after the S3, further comprising:

[0032] detecting a real-time pressure value of the column of the solvent separation tower, and issuing a pressure out-of-limit alarm information when the real-time pressure value reaches a pressure threshold.

[0033] In addition, the embodiment of the present application also provides a semi-batch device-solvent separation tower adaptive control system based on the semi-batch device-solvent separation tower adaptive control method described above, which comprises a solvent separation tower, a column reboiler, a condenser, a reflux tank and a controller, a first input end of the solvent separation tower is used for inputting crude solvent, and the crude solvent is output to the column reboiler for heating and gasification, then output to the solvent separation tower, and output through a second output end of the solvent separation tower, and after being cooled and liquefied by the condenser, the crude solvent is output to the reflux tank for storage, the reflux tank is connected with a second input end of the solvent separation tower, and is used for refluxing the stored solvent from the top of the solvent separation tower into the solvent separation tower, the controller calculates the column evaporation amount according to the reflux liquid level value of the reflux tank, controls the temperature rising rate of the column of the solvent separation tower, controls the steam amount of the column reboiler for heating the solvent separation tower according to the temperature value of the solvent separation tower, and controls the feed amount of the solvent separation tower according to the liquid level value of the solvent separation tower.

[0034] wherein, further comprising a pressure sensor arranged in the solvent separation tower and used for detecting pressure information in the solvent separation tower, the pressure sensor is connected with the controller and transmits the pressure information to the controller.

[0035] wherein, further comprising a display connected with the controller and used for displaying the real-time reflux liquid level value of the reflux tank, the column evaporation amount, the solvent density, the liquid level of the reflux tank, the temperature value of the solvent separation tower, the pressure information, the steam amount, the liquid level value of the solvent separation tower and the feed amount of the solvent separation tower.

[0036] wherein, further comprising a coefficient setting module connected with the controller and used for inputting a conversion coefficient of heat and temperature, a gain of steam amount and temperature change and a gain of solvent feed amount and liquid level change.

[0037] Compared with the prior art, the semi-batch device-solvent separation tower adaptive control method and system provided by the embodiment of the present application have the following advantages:

[0038] The adaptive control method and system based on the semi-batch device-solvent separation tower provided by the embodiment of the present application, by acquiring the real-time reflux liquid level value of the reflux tank connected with the output end of the solvent separation tower, calculating the tower kettle evaporation capacity of the solvent separation tower according to the real-time reflux liquid level value and the preset formula, and calculating and controlling the temperature rising rate of the tower kettle of the solvent separation tower according to the tower kettle evaporation capacity, in the control process, by integrating the artificial operation and historical data experience, and according to the evaporation capacity, the related parameters are adaptively adjusted, the adaptive control effect is achieved, and the control process is more fine and stable. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0040] Figure 1 The step flow schematic diagram of one embodiment of the adaptive control method based on the semi-batch device-solvent separation tower provided by the present application is shown in the figure.

[0041] Figure 2 The structure schematic diagram of another embodiment of the adaptive control method based on the semi-batch device-solvent separation tower provided by the present application is shown in the figure.

[0042] Figure 3 The structure schematic diagram of one embodiment of the adaptive control system based on the semi-batch device-solvent separation tower provided by the present application is shown in the figure.

[0043] Among them, 10-solvent separation tower, 20-reflux tank, 30-condenser, 40-tower kettle reboiler. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0045] Please refer to Figures 1-3 , Figure 1 The step flow schematic diagram of one embodiment of the adaptive control method based on the semi-batch device-solvent separation tower provided by the present application is shown in the figure. Figure 2 The structure schematic diagram of another embodiment of the adaptive control method based on the semi-batch device-solvent separation tower provided by the present application is shown in the figure. Figure 3A structural schematic diagram of one embodiment of the self-adaptive control system based on the semi-batch device-solvent separation tower provided by the present application.

[0046] In one specific embodiment, the self-adaptive control method based on the semi-batch device-solvent separation tower comprises:

[0047] S1: obtaining a real-time reflux liquid level value of a reflux tank connected to an output end of a solvent separation tower, and returning cooled solvent in the reflux tank to the solvent separation tower for reflux input, cooling gaseous distillate of the solvent separation tower, and liquefying distillate with a boiling point higher than the reflux solvent;

[0048] S2: calculating a tower kettle evaporation amount of the solvent separation tower according to the real-time reflux liquid level value and combining formula (1);

[0049] wherein, (1),

[0050] wherein, F E is the tower kettle evaporation amount, L rt1 is a liquid level value at a current time of the reflux tank, L rt2 is a liquid level value of the reflux tank n minutes ago, R r is a reflux tank radius, and ρ1 is a solvent density of the reflux tank;

[0051] S3: controlling a temperature rising rate of a tower kettle of the solvent separation tower according to the tower kettle evaporation amount and combining formula (2), (3), and (4);

[0052] (2) ;

[0053] (3) ;

[0054] (4) ;

[0055] wherein, ΔT is the temperature rising rate calculated according to the tower kettle evaporation amount; F E is the tower kettle evaporation amount; F a is a crude solvent feed amount; ω w is a water content in the crude solvent entering the solvent separation tower; ω a is a solvent content in the crude solvent; K3 is a heat and temperature conversion coefficient calculated according to historical data and physical properties; ΔT max is a maximum value of an allowed temperature change after change; ΔT max_t1 is a maximum value of an allowed temperature change after change at t1; ΔT minThe minimum value of the temperature change allowed after the change is ΔT min_t1 The minimum value of the temperature change allowed after the change at t1 is ΔT.

[0056] By obtaining the real-time reflux liquid level value of the reflux tank connected to the output end of the solvent separation tower, the tower kettle evaporation amount of the solvent separation tower is calculated according to the real-time reflux liquid level value and a preset formula, and the temperature rising rate of the tower kettle of the solvent separation tower is calculated and controlled. In the control process, by collecting artificial operation and historical data experience, a mode of using the rising rate of the reflux tank liquid level to characterize the evaporation amount is established, and the liquid level rising rate result is used to the temperature rising rate. When the raw material component changes, the temperature rising rate is changed to achieve adaptive control and correct the temperature change rate. When the liquid level rising rate is unreasonable, the temperature change rate can be adjusted according to the formula to achieve the effect of adaptive control, and the control process is more delicate and stable.

[0057] In the present application, in addition to the need to collect solvent in the reflux tank, a part of the solvent needs to be returned to the solvent separation tower. However, the liquid level of the reflux tank will always rise, and its storage capacity is limited, so it needs to be properly discharged.

[0058] In the present application, the solvent in the reflux tank is returned to the solvent separation tower to prevent some high-boiling-point substances from being distilled out and reaching the reflux tank due to excessive temperature. The high-boiling-point substances are cooled during the solvent return process to become liquid, thereby reducing the possibility of distillation of high-boiling-point substances and improving the solvent separation efficiency.

[0059] In an embodiment of the present application, after the S3, further comprising:

[0060] S4: determining whether the liquid level of the reflux tank is greater than the production value and has not been produced;

[0061] If not, S5: open the production valve of the reflux tank until the production valve is closed after production; if yes, turn to S2.

[0062] By opening the production valve of the reflux tank after the liquid level of the reflux tank is greater than the production value and has not been produced, and closing the production valve after production, not only can the reflux of the solvent be realized, but also the liquid level in the reflux tank can be kept at a safe value, thereby improving the safety and solvent extraction efficiency of operation.

[0063] In the present application, the production value is not limited and can be uniformly set or set by itself.

[0064] In order to further improve the solvent separation efficiency and prevent the temperature of the solvent separation tower from being too high to cause high-boiling, after the S3, further comprising:

[0065] S6: calculating the steam amount of the column reboiler for heating the solvent separation column according to the current temperature value of the solvent separation column and formula (5);

[0066] (5);

[0067] wherein F LS is the steam amount; T t1 is the current temperature of the column of the solvent separation column; T t2 is the temperature of the column of the solvent separation column n minutes ago; K1 is the gain of the steam amount and temperature change obtained according to historical data modeling.

[0068] By obtaining the temperature value of the solvent separation column in real time and calculating the steam amount of the column reboiler for heating the solvent separation column according to the corresponding formula, the temperature of the solvent separation column can be accurately controlled.

[0069] It should be noted that in the present application, the steam amount calculation formula is included but not limited to the above-mentioned formula, other formulas can also be used, and the gain value can also be obtained according to modeling and other methods, which can be a constant value or a variable value.

[0070] In addition, in the present application, as the separation is continuously carried out, the amount of high-boiling-point substances will continuously increase, and the liquid level value of the solvent separation column will continuously increase. In order to avoid the heat being diluted due to excessive feed amount, the overall instantaneous temperature being too low, and the separation efficiency being too low, the feed amount will affect the separation efficiency.

[0071] In order to improve the separation efficiency, in one embodiment, after the S3, the method further comprises:

[0072] S7: calculating the feed amount of the solvent separation column according to the current liquid level value of the solvent separation column and formula (6);

[0073] wherein, (6);

[0074] wherein F a is the crude solvent feed amount of the solvent separation column; L t1 is the current liquid level value of the column of the solvent separation column; L t1 is the liquid level value of the column of the solvent separation column n minutes ago; ΔL max is the maximum value of the allowed liquid level change; ΔL min is the minimum value of the allowed liquid level change; K2 is the gain of the solvent feed amount and liquid level change obtained according to historical data modeling.

[0075] By monitoring the liquid level of the solvent separation tower, according to the historical values and the solvent type in the crude solvent, the high-boiling content therein can be obtained according to the actual liquid level value, so as to control the feed amount and improve the separation efficiency.

[0076] For example, when the actual liquid level value is low, it represents that the high-boiling substance inventory is small, at this time, if the feed amount is large, due to the small inventory of the existing high-boiling substance, the temperature after mixing is low, on the contrary, when the actual liquid level value is high, it represents that the high-boiling substance inventory is large, so that even if the feed amount is large, it will not make the overall temperature after mixing too low, as long as heating is carried out, the gasification of the low-boiling solvent can be realized, and the reduction of the solvent separation efficiency is limited.

[0077] In order to further improve the management efficiency, in one embodiment, after the S3, further comprising:

[0078] Displaying the real-time reflux liquid level value of the reflux tank, the evaporation amount of the tower kettle, the solvent density, the liquid level of the reflux tank, the temperature value of the solvent separation tower, the steam amount, the liquid level value of the solvent separation tower and the feed amount of the solvent separation tower.

[0079] By setting the display to display the operating parameters of the related equipment, the operating data thereof can be obtained in real time, and the operating efficiency is improved.

[0080] In the present application, the data display method and display device are not limited, which can be separately displayed according to the needs, or different data can be displayed in turn, or the operating data of different equipment can be displayed, etc.

[0081] In order to further ensure the safety of the equipment operation, after the S3, further comprising:

[0082] Detecting the real-time pressure value of the tower kettle of the solvent separation tower, and issuing a pressure out-of-limit alarm information when the real-time pressure value reaches a pressure threshold.

[0083] By detecting the pressure value of the tower kettle of the solvent separation tower in real time, the high-boiling solvent is prevented from being separated out due to too high heating temperature, and the safety of the equipment operation is improved.

[0084] In the present application, the pressure threshold and the setting method are not limited.

[0085] In addition, the embodiment of the present application also provides a semi-batch device-solvent separation tower 10 adaptive control system adopting the semi-batch device-solvent separation tower 10 adaptive control method as described above, which comprises a solvent separation tower 10, a tower kettle reboiler 40, a condenser 30, a reflux tank 20 and a controller. The first input end of the solvent separation tower 10 is used for inputting crude solvent, and the crude solvent is output to the tower kettle reboiler 40 through the first output end arranged at the bottom, is output to the solvent separation tower 10 after being heated and gasified in the tower kettle reboiler 40, and is output through the second output end of the solvent separation tower 10, is cooled and liquefied through the condenser 30, and is output to the reflux tank 20 for storage. The reflux tank 20 is connected with the second input end of the solvent separation tower 10, and is used for inputting the stored solvent from the top of the solvent separation tower 10 to the solvent separation tower 10 in reflux. The controller calculates the tower kettle evaporation amount according to the reflux liquid level value of the reflux tank 20, controls the temperature rising rate of the tower kettle of the solvent separation tower 10, controls the steam amount of the tower kettle reboiler 40 for heating the solvent separation tower 10 according to the temperature value of the solvent separation tower 10, and controls the feed amount of the solvent separation tower 10 according to the liquid level value of the solvent separation tower 10.

[0086] Due to the semi-batch device-solvent separation tower 10 adaptive control system adopting the semi-batch device-solvent separation tower 10 adaptive control method as described above, the same beneficial effects as the semi-batch device-solvent separation tower 10 adaptive control method as described above are achieved, and the present application will not be repeated here.

[0087] In order to further improve the safety of the solvent separation tower 10, avoid poor separation safety caused by excessive pressure, or poor separation efficiency caused by insufficient pressure, etc., in an embodiment, the semi-batch device-solvent separation tower 10 adaptive control system further comprises a pressure sensor arranged in the solvent separation tower 10 and used for detecting the pressure information in the solvent separation tower 10. The pressure sensor is connected with the controller and transmits the pressure information to the controller.

[0088] By arranging the pressure sensor to acquire the pressure information in the solvent separation tower 10 in real time, the amount of gas can be kept within a certain range, which will not be too much, thereby ensuring the reliability of operation and will not be too little, and will not reduce the solvent separation efficiency.

[0089] In the present application, an alarm device can also be arranged. If the pressure, temperature, liquid level, feed amount, steam amount, etc. exceed the threshold value, an alarm can also be given, such as a light indicator, a sound indicator, a short message, etc.

[0090] In order to further improve the management efficiency, in an embodiment, the semi-batch device-solvent separation tower 10 adaptive control system further comprises a display connected to the controller, for displaying the real-time reflux liquid level value of the reflux tank 20, the tower kettle evaporation amount, the solvent density, the liquid level of the reflux tank 20, the temperature value of the solvent separation tower 10, the pressure information, the steam amount, the liquid level value of the solvent separation tower 10, and the feed amount of the solvent separation tower 10.

[0091] By displaying the operating parameters of the display-related equipment, the operating data is obtained in real time, and the operating efficiency is improved.

[0092] Since the coefficients in the related formulas are different under different equipment, and even may change with the model, in an embodiment, the semi-batch device-solvent separation tower 10 adaptive control system further comprises a coefficient setting module connected to the controller, for inputting the conversion coefficient of heat and temperature, the gain of steam amount and temperature change, and the gain of solvent feed amount and liquid level change.

[0093] By setting the conversion coefficient of heat and temperature, the gain of steam amount and temperature change, and the gain of solvent feed amount and liquid level change, the parameters can be flexibly set, which can be automatically selected according to the model, or manually selected by the staff, and the parameters can be specific values or corresponding formulas.

[0094] The solvent and other high-boiling crude solvent in the present application enter the solvent separation tower 10 from the middle of the tower body, flow into the tower kettle at the bottom after multiple heat and mass transfer, the tower kettle is heated by steam, the temperature of the tower kettle is controlled, and the solvent and water are evaporated. After the evaporated material is fully vapor-liquid contacted with the feed and reflux material, it is condensed by the tower bottom condenser 30 and flows into the reflux tank 20. Part of the solvent in the reflux tank 20 is refluxed according to the proportion, and the other part is discharged to the corresponding storage tank for standby. When the high-boiling substances in the tower kettle accumulate to a certain amount, the tower kettle liquid level and the required rectification temperature will rise continuously, at which time the feeding is stopped, the remaining solvent is evaporated, and then the heating is stopped, and the residual liquid in the tower kettle is discharged.

[0095] The solvent refluxed from the reflux tank 20 in the present application is a low-boiling solvent, a liquid. The reflux liquid returns to the tower from the top of the tower, and is fully contacted with the gas phase rising after being heated by the tower kettle. The heavy components in the ascending gas condense after being cooled, and the light components in the descending liquid gasify after being heated. Each contact is a simple distillation process. Through repeated condensation and gasification, the light and heavy components can be more effectively separated, and the precision of product separation is increased.

[0096] The application utilizes historical data calculation to give different temperature rising rate ranges in different stages of the system, and controls the temperature of the tower kettle by adjusting the temperature rising rate.

[0097] The discharge mode of the solvent in the reflux tank 20 is changed from continuous discharge to automatic intermittent discharge, so that the system can calculate the evaporation amount of the device per unit period, thereby adjusting the temperature rising rate in the tower kettle, and achieving self-adaptive control.

[0098] By changing the historical operation data and the temperature rising rate, the content of the reaction raw material and the high-boiling substance in the tower kettle, the different tower kettle liquid level rising rates are set, and the addition amount of the raw material is controlled to achieve the best rectification effect.

[0099] The evaporation amount is calculated as follows:

[0100] (1),

[0101] Wherein, F E is the evaporation amount of the tower kettle, L rt1 is the current liquid level value of the reflux tank 20, L rt2 is the liquid level value of the reflux tank 20n minutes ago, R r is the radius of the reflux tank 20, and ρ1 is the density of the solvent in the reflux tank 20, which is read by an online density meter.

[0102] The steam adjustment amount is calculated as follows:

[0103] (5) ;

[0104] Wherein, F LS is the steam amount; T t1 is the current temperature of the tower kettle of the solvent separation tower 10; T t2 is the temperature of the tower kettle of the solvent separation tower 10n minutes ago; K1 is the gain of the steam amount and temperature change obtained by modeling according to historical data;

[0105] The feed adjustment amount is as follows:

[0106] (6) ;

[0107] Wherein, F a is the crude solvent feed amount of the solvent separation tower 10; L t1 is the current liquid level value of the tower kettle of the solvent separation tower 10; L t1 is the liquid level value of the tower kettle of the solvent separation tower 10n minutes ago; ΔL max is the maximum value of the allowed liquid level change; ΔLmin is the minimum value of the temperature change allowed after the change; ΔT is the temperature change rate calculated according to the tower evaporation amount; F

[0108] The temperature rise rate is set as follows according to the evaporation amount:

[0109] (2);

[0110] (3);

[0111] (4);

[0112] wherein, ΔT is the temperature rise rate calculated according to the tower evaporation amount; F E is the tower evaporation amount; F a is the feed amount of the crude solvent; ω w is the content of water in the crude solvent entering the solvent separation tower 10; ω a is the content of solvent in the crude solvent; K3 is the conversion coefficient of heat and temperature calculated according to historical data and physical properties; ΔT max is the maximum value of the temperature change allowed after the change; ΔT max_t1 is the maximum value of the temperature change allowed at t1 after the change; ΔT min is the minimum value of the temperature change allowed after the change; ΔT min_t1 is the minimum value of the temperature change allowed at t1 after the change.

[0113] In the method and system described above in the present application, the artificial operation and historical data experience are mainly collected based on data acquisition software; an operation mode for controlling the temperature change rate and the liquid level change rate of the tower is established, which more intuitively displays the influence of the high-boiling substances in the tower on the temperature required for rectification; a mode for characterizing the evaporation amount by the liquid level rise rate of the reflux tank 20 is established, and the liquid level rise rate result is applied to the temperature rise rate, so that the effect of self-adaptive control is achieved by changing the temperature rise rate when the raw material composition changes.

[0114] The temperature change rate is used to control the temperature in the tower, the liquid level rise rate in the reflux tank 20 is used to characterize the evaporation amount, the temperature change rate is corrected, and the control of the solvent separation tower 10 is standardized and intelligentized, which has the following advantages compared with the original manual operation process:

[0115] The temperature and liquid level in the tower are controlled by using the change rate, which can reflect the influence of the high-boiling substances in the tower on the rectification temperature in the whole cycle of the operation of the solvent separation tower 10;

[0116] The evaporation amount is characterized by the rising rate of the liquid level in the reflux tank 20, and when the liquid level rising rate is unreasonable, the temperature change rate can be adjusted according to the formula; when the device receives different high-boiling solvent content solvents, the related parameters are automatically adjusted to achieve self-adaptive control.

[0117] The more delicate and smooth characteristics of the program provide more sensitive and smooth control for solvent treatment, reduce the phenomenon of high solvent content in the residual liquid in the tower kettle or unqualified crude solvent product, improve the operation cycle and solvent treatment capacity of the device, and save part of the labor.

[0118] The potential value of historical data is deeply mined, and self-adaptive control is realized by collecting and analyzing DCS bottom layer data for one year.

[0119] In the self-adaptive control of the semi-batch device solvent separation tower 10 in the chemical production process, the APC expert controller module is used as an automatic control technology operation platform, but is not limited to it. Correspondingly, the operation platform / environment also includes: the sequence control logic module of the DCS; other control type software connected to the DCS through the OPC protocol, etc.

[0120] In summary, the self-adaptive control method and system based on the semi-batch device-solvent separation tower provided by the embodiment of the present application, by acquiring the real-time reflux liquid level value of the reflux tank connected to the output end of the solvent separation tower, calculating the tower kettle evaporation amount of the solvent separation tower according to the real-time reflux liquid level value and the preset formula, and calculating and controlling the temperature rising rate of the tower kettle of the solvent separation tower according to the tower kettle evaporation amount, in the control process, by integrating artificial operation and historical data experience, a way of using the rising rate of the reflux tank liquid level to characterize the evaporation amount is established, and the related parameters are self-adaptively adjusted according to the evaporation amount, to achieve the effect of self-adaptive control, and the control process is more delicate and smooth.

[0121] The self-adaptive control method and system based on the semi-batch device-solvent separation tower provided by the present application are described in detail above. In this paper, specific examples are applied to explain the principles and implementation methods of the present application, and the above description of the embodiments is only used to help understand the method and its core idea of the present application. It should be pointed out that for ordinary skilled persons in the technical field, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A method for adaptive control of a semi-batch apparatus-solvent separation column, characterized in that, Comprise: S1: obtain the real-time reflux liquid level value of the reflux tank connected to the output end of the solvent separation tower, and input the cooled solvent in the reflux tank to the solvent separation tower, cool the gaseous distillate of the solvent separation tower, and liquefy the distillate with a boiling point higher than the reflux solvent; S2: calculate the tower kettle evaporation amount of the solvent separation tower according to the real-time reflux liquid level value combined with formula (1); wherein (1), where F E is the evaporating amount of the column, L rt1 is the current liquid level value of the reflux tank, L rt2 is the liquid level value of the reflux tank n minutes ago, R r is the reflux tank radius, and p1 is the solvent density of the reflux tank. S3: control the temperature rising rate of the tower kettle of the solvent separation tower according to the tower kettle evaporation amount combined with formulas (2), (3), and (4); （2）； （3）； （4）； Wherein, ΔT is the temperature rising rate calculated according to the tower kettle evaporation amount; F E is the tower kettle evaporation amount; F a is the crude solvent feed amount; ω w is the water content in the crude solvent entering the solvent separation tower; ωa is the solvent content in the crude solvent; K3 is a heat and temperature conversion coefficient calculated according to historical data and physical properties; ΔT max is the maximum value of the allowed temperature change after the change; ΔT max_t1 is the maximum value of the allowed temperature change at t1 moment after the change; ΔT min is the minimum value of the allowed temperature change after the change; ΔT min_t1 is the minimum value of the allowed temperature change at t1 moment after the change.

2. The method for adaptive control of a semi-batch apparatus-solvent separation column according to claim 1, wherein, After S3, further comprising: S4: judge whether the liquid level of the reflux tank is greater than the production value and has not been produced; If yes, S5: open the production valve of the reflux tank until the production valve is closed after production; if no, turn to S2.

3. The method for adaptive control of a semi-batch apparatus-solvent separation column according to claim 2, wherein, After S3, further comprising: S6: calculate the steam amount of the tower kettle reboiler for heating the solvent separation tower according to the current temperature value of the solvent separation tower and formula (5); （5）； where F LS is the vapor amount; T t1 is the temperature of the column at the current time; T t2 is the temperature of the column n minutes ago; and K1 is a gain of the vapor amount and temperature change modeled from historical data.

4. The method for adaptive control of a semi-batch apparatus-solvent separation column according to claim 3, wherein, After S3, further comprising: S7: calculate the feed amount of the solvent separation tower according to the current liquid level value of the solvent separation tower and formula (6); wherein (6); where F a is the crude solvent feed rate to the solvent separation column; L t1 is the current level value of the column sump of the solvent separation column; L t1 is the level value of the column sump of the solvent separation column n minutes ago; ΔL max is the maximum value of the level change allowed; ΔL min is the minimum value of the level change allowed; K2is the gain of the solvent feed rate to the level change based on historical data modeling.

5. The method for adaptive control of a semi-batch apparatus-solvent separation column according to claim 4, wherein, After S3, further comprising: Display the real-time reflux liquid level value of the reflux tank, the tower kettle evaporation amount, the solvent density, the liquid level of the reflux tank, the temperature value of the solvent separation tower, the steam amount, the liquid level value of the solvent separation tower, and the feed amount of the solvent separation tower.

6. The method for adaptive control of a semi-batch apparatus-solvent separation column according to claim 1, wherein, After S3, further comprising: Detect the real-time pressure value of the tower kettle of the solvent separation tower, and issue a pressure out-of-range warning message when the real-time pressure value reaches a pressure threshold.

7. A self-adaptive control system based on semi-batch device-solvent separation column, characterized in that, The semi-batch device-based solvent separation tower self-adaptive control method according to any one of claims 1-6 comprises a solvent separation tower, a tower kettle reboiler, a condenser, a reflux tank, and a controller. The first input end of the solvent separation tower is used to input crude solvent, which is output to the tower kettle reboiler for heating and gasification, then output to the solvent separation tower through the first output end arranged at the bottom, and finally output to the reflux tank for storage after being cooled and liquefied by the condenser. The reflux tank is connected to the second input end of the solvent separation tower, and is used to input the stored solvent from the top of the solvent separation tower to the solvent separation tower. The controller calculates the tower kettle evaporation amount according to the reflux liquid level value of the reflux tank, controls the temperature rising rate of the tower kettle of the solvent separation tower, and controls the steam amount of the tower kettle reboiler for heating the solvent separation tower according to the temperature value of the solvent separation tower, and controls the feed amount of the solvent separation tower according to the liquid level value of the solvent separation tower.

8. The adaptive control system for a semi-batch apparatus-solvent separation column according to claim 7, wherein, Further comprising a pressure sensor arranged in the solvent separation tower for detecting pressure information in the solvent separation tower, wherein the pressure sensor is connected to the controller and transmits the pressure information to the controller.

9. The adaptive control system for a semi-batch apparatus-solvent separation column according to claim 8, wherein, Also included is a display connected to the controller for displaying real-time reflux level values of the reflux drum, the tower vaporization amount, the solvent density, the level of the reflux drum, the temperature values of the solvent separation tower, the pressure information, the steam amount, the level values of the solvent separation tower, and the feed amount of the solvent separation tower.

10. The adaptive control system for a semi-batch apparatus-solvent separation column according to claim 9, wherein, Also included is a coefficient setting module connected to the controller for inputting conversion coefficients of heat and temperature, gains of steam amount and temperature change, and gains of solvent feed amount and level change.

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