A balance full-automatic separation control method for a rectifying column system

Abstract

The present application relates to rectification technical field, particularly to a kind of rectification tower system balance full-automatic separation control method, rectification tower system includes rectification I tower, control method includes to rectification I tower is carried out material balance control and gas-liquid equilibrium control, gas-liquid equilibrium control is used to control the amount of backflow of material backflow to rectification I tower;The material balance control includes: detecting the actual feed flow of rectification I tower and the actual liquid level value of the first reflux tank corresponding to rectification I tower, in combination with the overhead take-off component set point of rectification I tower and the overhead take-off component density, the overhead take-off material flow of rectification I tower is calculated and controlled in real time.By the method, the stability and efficiency of rectification tower system are improved, and the energy consumption cost and the volatility problem of product are reduced.

Description

Technical Field

[0001] This invention relates to the field of distillation technology, and in particular to a fully automated separation control method for the equilibrium of a distillation column system. Background Technology

[0002] Currently, the automated control of distillation columns mainly utilizes temperature, pressure, and liquid level measuring points on the distillation column and auxiliary equipment to correlate with flow rate and regulating valves for automatic control (divided into cascade control and automatic control). For example, the column bottom liquid level is correlated with the reflux regulating valve or reflux flow rate for adjustment and control, and the feed flow rate and feed regulating valve are automatically controlled.

[0003] The above-mentioned technical solutions are relatively simple and have low system adjustment efficiency, making it impossible to achieve full automation. They require continuous adjustments by personnel. For example, after adjusting the feed flow rate, personnel need to adjust the distillation column bottom output, top output, steam consumption, reflux flow, etc. Although the implementation of partial flow and level automation can appropriately reduce personnel operation, the adjustment efficiency is too low, the structure is simple, and it cannot quickly meet the needs of system adjustment. Essentially, after adjusting the previous parameters, it is necessary to wait for the subsequent measurement point to deviate from the set value (the actual value deviates from the set value) before making the next adjustment. For example, after increasing the feed rate, it is necessary to wait until the reflux tank level rises and deviates from the set value before adjusting the top output flow rate. At the same time, due to the change in feed rate, but the output rate does not change in time, the material inside the system accumulates, the steam energy consumption increases, the system impurity separation effect decreases, and the overall system energy consumption and separation effect are affected. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a fully automated separation control method for a distillation column system, which improves the stability and efficiency of the distillation column system, saves on manual operation costs, avoids human error, reduces energy consumption costs and product volatility, and also improves the separation effect of the distillation column and enhances product quality.

[0005] This invention is achieved by adopting the following technical solution:

[0006] A fully automated separation control method for a distillation column system, the distillation column system including a distillation column I, the control method including material balance control and gas-liquid balance control of distillation column I, the gas-liquid balance control being used to control the reflux rate of material returning to distillation column I; the material balance control including: detecting the actual feed flow rate of distillation column I and the actual liquid level value of the first reflux tank corresponding to distillation column I, and, in conjunction with the set value of the top-collected component of distillation column I and the density of the top-collected component, calculating and controlling the top-collected material flow rate of distillation column I in real time; wherein, the calculation method for the top-collected material flow rate of distillation column I is as follows:

[0007] The flow rate of the top product of distillation column I = actual feed flow rate * set value of top product component / density of top product component + first correction value; the first correction value = (actual liquid level value of the first reflux tank - set liquid level value of the first reflux tank) / liquid level deviation setting value of the first reflux tank * set correction value.

[0008] The material balance control also includes controlling the bottom discharge rate of distillation column I based on the actual bottom liquid level of distillation column I.

[0009] The gas-liquid balance control specifically refers to controlling the reflux rate of material back into distillation column I based on the actual temperature of the rectification section or the actual bottom liquid level of distillation column I.

[0010] The gas-liquid balance control specifically refers to: setting a reflux ratio coefficient value, where the reflux ratio is the ratio of the reflux flow rate to the flow rate of the material collected from the top of the column; calculating the reflux flow rate output value based on the calculated flow rate of the material collected from the top of the column; calculating the deviation between the actual temperature and the preset temperature or the deviation between the actual bottom liquid level and the preset bottom liquid level based on the actual temperature of the rectification section of rectification column I or the actual bottom liquid level of rectification column I; and calculating and controlling the reflux flow rate of material returning to rectification column I.

[0011] Return flow rate = Return flow rate output value + Second correction value; Second correction value = (Actual temperature - Preset temperature) / Temperature deviation setting * Setting correction value; Or, Return flow rate = Return flow rate output value + Third correction value; Third correction value = (Actual column bottom liquid level - Preset column bottom liquid level) / Column bottom liquid level deviation setting value * Setting correction value.

[0012] When it is a multi-component impurity separation distillation column, the gas-liquid balance is controlled according to the actual temperature of the rectification section of the distillation column; when it is a single-component impurity separation distillation column, the gas-liquid balance is controlled according to the actual bottom liquid level of the distillation column.

[0013] It also includes energy balance control for distillation column I, specifically referring to: controlling the circulating water volume based on the material outlet temperature after cooling by the first cooler corresponding to distillation column I; and controlling the steam volume based on the material vapor phase temperature near the reboiler in the column bottom.

[0014] The steam quantity is controlled based on the material vapor phase temperature near the first reboiler in the tower reboiler, specifically including:

[0015] Steam quantity = Set base steam flow rate + Fourth correction value; Fourth correction value = (Actual material vapor phase temperature near the first reboiler in the tower bottom - Preset material vapor phase temperature near the first reboiler in the tower bottom) / Vapor phase temperature deviation setting value * Set correction value.

[0016] The distillation system also includes a distillation column II connected in series with distillation column I. The control method further includes top-out control and reflux control for distillation column II. Specifically, the top-out control refers to controlling the top-outflow rate based on the top temperature of distillation column II, and the reflux control refers to controlling the reflux flow rate based on the liquid level of the second reflux tank corresponding to distillation column II.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. In this invention, through material balance control and gas-liquid balance control, the distillation column system can be fully automated in terms of feed, discharge, and separation effect, improving the accuracy and timeliness of control. Accuracy refers to the ability of this invention to adjust based on liquid level or temperature deviations, calculating and outputting control values ​​regardless of magnitude. Timeliness refers to the ability of this invention to calculate in real time. The difference from traditional PID control is that traditional control only starts adjusting when the actual value reaches the set value, without premature reduction. For example, if the temperature is controlled at 50℃ and the steam flow rate is 10t / h, when the temperature drops to 49℃, traditional PID control will increase the steam flow rate continuously until the temperature recovers to 50℃ before adjusting to reduce the steam flow rate, resulting in temperatures exceeding 50℃ and failing to recover quickly. The control method of this invention calculates the output value based on real-time deviation, increasing or decreasing synchronously without exhibiting a lag-period sinusoidal fluctuation curve.

[0019] Furthermore, when performing material balance control, by analyzing the separation of different volatile components of the material in the distillation column, the feed components and the actual top-collected components can be obtained through detection methods. Since the material components in industrial production are not constant and have a certain degree of fluctuation, this invention innovatively introduces a first correction value, which can solve the fluctuation problem in actual industrial production and improve the stability and efficiency of the system.

[0020] 2. In this invention, when performing gas-liquid balance control, different parameters can be selected for corresponding control according to the type of component separation, resulting in better control accuracy and stability.

[0021] 3. The present invention also includes energy balance control, which can automatically control energy consumption. Combined with material balance control and gas-liquid balance control, this control method is more comprehensive.

[0022] 4. In this invention, the series-connected distillation columns I and II employ high-low pressure coupling, reducing energy consumption and improving energy utilization efficiency. However, this also means that the heat source for distillation column II depends on distillation column I. Changes in the steam consumption of distillation column I affect the bottom liquid level, necessitating control of the rising steam and reflux liquid flow. In other words, the reflux flow is controlled in relation to the bottom liquid level to cope with heat changes. To address these characteristics, the reflux flow rate is controlled based on the liquid level in the reflux tank of distillation column II, employing a different control method than distillation column I, resulting in better gas-liquid balance in distillation column II.

[0023] Since the production process of the Distillation Column II requires the separation of unwanted components from the top of the column, it is necessary to control the quantity and composition. That is, through calculation and simulation, it is determined that the material composition at a certain temperature at the top of the column meets the production requirements (the top of the column should not over-collect the material we need, nor should it under-collect the unwanted material). In order to cope with the actual changes in the amount of material to be separated from the incoming material (which may be more or less at times), the top of the Distillation Column II is controlled according to the top collection temperature to achieve automatic adjustment of the top collection amount of the Distillation Column II. Attached Figure Description

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein:

[0025] Figure 1 This is a schematic diagram of the distillation column system in this invention;

[0026] Marked in the image:

[0027] 1. Distillation column I; 2. Distillation column II; 3. First temperature detector; 4. Second temperature detector; 5. Third temperature detector; 6. Fourth temperature detector; 7. Fifth temperature detector; 8. First liquid level detector; 9. Second liquid level detector; 10. Third liquid level detector; 11. Fourth liquid level detector; 12. First regulating valve; 13. Second regulating valve; 14. Third regulating valve; 15. Fourth regulating valve; 16. Fifth regulating valve; 17. Sixth regulating valve; 18. Seventh regulating valve. 19. Eighth regulating valve, 20. Fourth gauge, 21. First reflux tank, 22. First reboiler, 23. Second reboiler, 24. First cooler, 25. Second cooler, 26. First reflux pump, 27. Second reflux pump, 28. First gauge, 29. Second gauge, 30. Third gauge, 31. Tenth regulating valve, 32. Eleventh regulating valve, 33. Second reflux tank, 34. Third cooler, 35. Fourth flow meter, 36. Fifth gauge. Detailed Implementation

[0028] Example 1

[0029] As a basic embodiment of the present invention, the present invention includes a fully automated separation control method for a distillation column system. The distillation column system includes a distillation column I, and the control method includes material balance control and gas-liquid balance control for distillation column I. The gas-liquid balance control is used to control the reflux rate of material returning to distillation column I. The material balance control includes: detecting the actual feed flow rate of distillation column I and the actual liquid level value of the first reflux tank 21 corresponding to distillation column I; combining this with the set value of the top-collected component of distillation column I and the density of the top-collected component, calculating and controlling the top-collected material flow rate of distillation column I in real time. Specifically, the calculation method for the top-collected material flow rate of distillation column I is as follows:

[0030] The flow rate of the top product from distillation column 1 = actual feed flow rate * set value of top product component / density of top product component + first correction value. Wherein, the first correction value = (actual liquid level of first reflux tank 21 - set liquid level of first reflux tank 21) / set liquid level deviation of first reflux tank 21 * set correction value. The set liquid level of first reflux tank 21, the set liquid level deviation of first reflux tank 21, and the set correction value can be obtained through simulation calculations or by analyzing historical operating data.

[0031] Example 2

[0032] As a preferred embodiment of the present invention, the present invention includes a fully automated separation control method for a distillation column system. The distillation column system includes a distillation column I, and the control method includes material balance control and gas-liquid balance control of distillation column I. Specifically, the gas-liquid balance control is used to control the reflux rate of material back into distillation column I. Specifically, the reflux rate of material back into distillation column I can be controlled based on the actual temperature of the rectification section of distillation column I or the actual bottom liquid level of distillation column I.

[0033] The material balance control includes controlling the flow rate of the top product from distillation column I and controlling the reboiler product from distillation column I. The reboiler product from distillation column I can be controlled based on the actual reboiler level. Specifically, controlling the flow rate of the top product from distillation column I involves detecting the actual feed flow rate of distillation column I and the actual level of the corresponding first reflux tank 21, and, in conjunction with the set value of the top product component and its density, calculating and controlling the flow rate of the top product from distillation column I in real time. Specifically, the calculation method for the flow rate of the top product from distillation column I is as follows:

[0034] The flow rate of the top product from distillation column 1 = actual feed flow rate * set value of top product component / density of top product component + first correction value. Wherein, the first correction value = (actual liquid level value of first reflux tank 21 - set liquid level value of first reflux tank 21) / set liquid level deviation value of first reflux tank 21 * set correction value.

[0035] Example 3

[0036] In another preferred embodiment of the present invention, the present invention includes a fully automated separation control method for a distillation column system. The distillation column system includes a distillation column I, and the control method includes material balance control, gas-liquid balance control, and energy balance control for distillation column I. Specifically, the gas-liquid balance control is used to control the reflux rate of material back into distillation column I. The energy balance control specifically refers to: controlling the circulating water flow rate based on the outlet temperature of the material cooled by the first cooler 24 corresponding to distillation column I; and controlling the steam flow rate based on the vapor phase temperature of the material near the first reboiler 22 in the column reboiler.

[0037] The material balance control includes: detecting the actual feed flow rate of distillation column I and the actual liquid level of the first reflux tank 21 corresponding to distillation column I; combining this with the set value of the top-collected component of distillation column I and the density of the top-collected component, and calculating and controlling the top-collected material flow rate of distillation column I in real time. Specifically, the calculation method for the top-collected material flow rate of distillation column I is as follows:

[0038] The flow rate of the top product from distillation column 1 = actual feed flow rate * set value of top product component / density of top product component + first correction value. Wherein, the first correction value = (actual liquid level value of first reflux tank 21 - set liquid level value of first reflux tank 21) / set liquid level deviation value of first reflux tank 21 * set correction value.

[0039] The above control methods enable comprehensive automated control of the distillation system of a single distillation column, encompassing feed and discharge, energy consumption, and separation efficiency.

[0040] Example 4

[0041] As the preferred embodiment of the present invention, the present invention includes a fully automated separation control method for a distillation column system, wherein, as per the appendix to the specification... Figure 1 The distillation column system includes a distillation column I 1 and a distillation column II 2 arranged in series, and also includes a first reflux tank 21 and a first reboiler 22 corresponding to distillation column I 1, as well as a second reflux tank 33 and a second reboiler 23 corresponding to distillation column II 2.

[0042] The feed line of distillation column I is also equipped with a first regulating valve 12 and a first sensor 28, the first sensor 28 being used to detect the actual feed flow rate. The bottom outlet line of distillation column I is also equipped with a second regulating valve 13 and a third cooler 34. The bottom of distillation column I is also equipped with a second level detector 9, used to detect the actual bottom liquid level of distillation column I. A first temperature detector 3 is located near the first reboiler 22 at the bottom of distillation column I, used to detect the actual vapor phase temperature of the material near the first reboiler 22. A second temperature detector 4 is also located in the upper section of distillation column I, used to detect the actual temperature of the rectification section (upper section) of distillation column I. The first reboiler 22 of distillation column I is connected to a steam pipe, the other end of which is connected to a steam source. A fourth regulating valve 15 and a fourth flow meter 35 are also installed on the steam pipe.

[0043] The top outlet of distillation column I 1 is connected to a first pipeline. This first pipeline is sequentially equipped with a first cooler 24, a fifth temperature detector 7, a first reflux tank 21, and a first reflux pump 26. The output end of the first pipeline is connected to two branch pipelines. One branch pipeline is equipped with a sixth regulating valve 17 and a second sensor 29, and is connected to the feed inlet of distillation column II 2. The other branch pipeline is equipped with a third regulating valve 14 and a third sensor 30, and is connected to the upper part of distillation column I 1. The material at the top outlet of distillation column I 1 needs to exchange heat with a second reboiler 23 before entering the first cooler 24 through the first pipeline. The first reflux tank 21 is also equipped with a first level detector 8.

[0044] The upper section of distillation column II is also equipped with a third temperature detector 5, used to detect the actual temperature of the rectification section (upper section) of distillation column II. The bottom of distillation column II is also equipped with a fourth liquid level detector 11, used to detect the actual liquid level in the bottom of distillation column II. The bottom outlet pipeline of distillation column II is also equipped with a seventh regulating valve 18.

[0045] The top outlet of distillation column II 2 is connected to a second pipeline. This second pipeline is sequentially equipped with a second cooler 25, a fourth temperature detector 6, a second reflux tank 33, and a second reflux pump 27. The output end of the second pipeline is connected to two branch pipelines. One branch pipeline is equipped with an eighth regulating valve 19 and a fourth sensor 20; the other branch pipeline is equipped with a fifth regulating valve 16 and a fifth sensor 36, and is connected to the upper part of distillation column II 2. The second reflux tank 33 is also equipped with a third level detector 10.

[0046] The first cooler 24 is connected to the circulating water via a first circulating water pipe, and the first circulating water pipe is also equipped with a tenth regulating valve 31. The second cooler 25 is connected to the circulating water via a second circulating water pipe, and the second circulating water pipe is also equipped with an eleventh regulating valve 32.

[0047] Based on the above-mentioned distillation column system, the present invention provides a fully automated separation control method for the balance of a distillation column system, including material balance control, gas-liquid balance control and energy balance control for distillation column I, and top product control, reflux control, bottom product control and circulating water volume control for distillation column II.

[0048] The material balance control for distillation column I includes controlling the top product of distillation column I and controlling the bottom product of distillation column I. Specifically, controlling the top product of distillation column I refers to: detecting the actual feed flow rate of distillation column I based on the first detector 28, detecting the actual liquid level value of the first reflux tank 21 based on the first liquid level detector 8; combining the set value of the top product component of distillation column I and the density of the top product component, calculating the top product flow rate of distillation column I in real time, and controlling the top product flow rate of distillation column I through the sixth regulating valve 17. The calculation method for the top product flow rate of distillation column I is as follows:

[0049] The flow rate of the top product from distillation column 1 = actual feed flow rate * set value of top product component / density of top product component + first correction value. First correction value = (actual liquid level of first reflux tank 21 - set liquid level of first reflux tank 21) / set liquid level deviation of first reflux tank 21 * set correction value. Wherein, the density of the top product component is actually the density of the top product under controlled temperature and pressure.

[0050] For example, the feed flow rate is 210t / h, the extracted component is 33%, the set liquid level is 50%, the actual liquid level is 55%, the liquid level deviation setting is 1%, the set correction value is 0.2, and the density value is 1.285.

[0051] The output value is calculated as follows: 210 * 0.33 / 1.285 + ((55% - 50%) / 1% * 0.2) = 54.93

[0052] For example, the feed flow rate is 210t / h, the extracted component is 33%, the set liquid level is 50%, the actual liquid level is 45%, the set deviation is 1%, the set correction is 0.2, and the density value is 1.285.

[0053] The output value is calculated as follows: 210 * 0.33 / 1.285 + ((45% - 50%) / 1% * 0.2) = 52.93

[0054] The control of the bottom discharge rate of distillation column I specifically refers to controlling the bottom discharge rate of distillation column I by controlling the second regulating valve 13 based on the actual bottom liquid level of distillation column I detected by the second liquid level detector 9.

[0055] The gas-liquid balance control of distillation column I specifically refers to controlling the reflux rate of material back into distillation column I based on the actual temperature of the rectification section or the actual bottom liquid level of distillation column I. Specifically, when distillation column I is a multi-component impurity separation distillation column, the gas-liquid balance is controlled based on the actual temperature of the rectification section; when distillation column I is a single-component impurity separation distillation column, the gas-liquid balance is controlled based on the actual bottom liquid level of distillation column I. This prevents all the gas phase in distillation column I from passing through the first cooler 24 into the first reflux tank 21, which would reduce the separation effect of components and impurities, and also prevents excessive reflux material from returning to distillation column I, which would reduce product yield and steam energy consumption.

[0056] Specifically, a reflux ratio coefficient is set, whereby the reflux ratio is the ratio of the reflux flow rate to the flow rate of the material collected from the top of the column. The reflux flow rate output value is calculated based on the calculated flow rate of the material collected from the top of the column. The deviation between the actual temperature and the preset temperature, or the deviation between the actual bottom liquid level and the preset bottom liquid level, is calculated based on the actual temperature of the rectification section of rectification column I detected by the second temperature detector 4, or the actual bottom liquid level of rectification column I detected by the second level detector 9. The reflux flow rate of material returning to rectification column I is then calculated and controlled.

[0057] Return flow rate = Return flow rate output value + Second correction value, Second correction value = (Actual temperature - Preset temperature) / Temperature deviation setting * Setting correction value.

[0058] The return flow output value is a return flow value set by simulating or statistically analyzing previously running data.

[0059] Alternatively, reflux flow = reflux flow output value + third correction value; third correction value = (actual bottom liquid level - preset bottom liquid level) / bottom liquid level deviation setting * setting correction value.

[0060] Energy balance control is implemented for distillation column I. Specifically, the circulating water volume is controlled based on the material outlet temperature after cooling by the first cooler 24 of distillation column I; and the steam volume is controlled based on the material vapor phase temperature near the first reboiler 22 in the column bottom.

[0061] Specifically, the outlet temperature of the material cooled by the first cooler 24 can be detected by the fifth temperature detector 7, and the circulating water volume can be controlled by controlling the tenth regulating valve 31. The vapor phase temperature of the material detected by the first temperature detector 3 can be used to control the steam volume by controlling the fourth regulating valve 15. The specific calculation method for the steam volume is as follows:

[0062] Steam quantity = Set base steam flow rate + fourth correction value; Fourth correction value = (Actual material vapor phase temperature near the first reboiler 22 in the tower bottom - Preset material vapor phase temperature near the first reboiler 22 in the tower bottom) / Vapor phase temperature deviation setting * Set correction value.

[0063] The control of the top product of distillation column II specifically refers to: based on the actual temperature of the top of distillation column II detected by the third temperature detector 5, comparing it with a preset top temperature, and controlling the top product rate by controlling the eighth regulating valve 19. The top product rate can be calculated in the following way:

[0064] The top product of distillation column 2 = set product + fifth correction value; fifth correction value = (actual top temperature - preset top temperature) / temperature deviation setting * set correction value.

[0065] Reflux control of distillation column II specifically refers to: based on the actual liquid level of the second reflux tank 33 detected by the third liquid level detector 10, comparing it with the preset liquid level, and controlling the reflux flow rate by controlling the fifth regulating valve 16. The reflux flow rate can be calculated in the following way:

[0066] The reflux rate of distillation column 2 = the set reflux rate + the sixth correction value; the sixth correction value = (actual liquid level - preset liquid level) / liquid level deviation setting * set correction value.

[0067] The control of the bottom discharge of distillation column II specifically refers to controlling the bottom discharge rate of distillation column II by controlling the seventh regulating valve 18 based on the actual bottom liquid level of distillation column II detected by the fourth liquid level detector 11.

[0068] The bottom product output = the set bottom product output + the seventh correction value; the seventh correction value = (actual bottom liquid level - preset bottom liquid level) / liquid level deviation setting * set correction value.

[0069] The control of circulating water volume in distillation column II specifically refers to: the outlet temperature of the material cooled by the second cooler 25 can be detected by the fourth temperature detector 6, and the circulating water volume can be controlled by controlling the eleventh regulating valve 32.

[0070] The above control methods enable comprehensive automated control of a distillation system with multiple interconnected distillation columns, considering factors such as feed inlet / outlet, energy consumption, and separation efficiency.

[0071] In summary, any other corresponding modifications made by those skilled in the art after reading this invention document, without requiring creative mental effort, based on the technical solutions and concepts of this invention, are all within the scope of protection of this invention.

Claims

1. A fully automated separation control method for a distillation column system, characterized in that: The distillation column system includes distillation column I (1), and the control method includes material balance control and gas-liquid balance control of distillation column I (1). The gas-liquid balance control is used to control the reflux rate of material back into distillation column I (1). The material balance control includes: detecting the actual feed flow rate of distillation column I (1) and the actual liquid level of the first reflux tank (21) corresponding to distillation column I (1), and, in conjunction with the set value of the top-collected component of distillation column I (1) and the density of the top-collected component, calculating and controlling the top-collected material flow rate of distillation column I (1) in real time; wherein, the calculation method for the top-collected material flow rate of distillation column I (1) is as follows: The flow rate of the top product of distillation column I (1) = actual feed flow rate * set value of top product component / density of top product component + first correction value; the first correction value = (actual liquid level value of first reflux tank (21) - set liquid level value of first reflux tank (21)) / liquid level deviation setting value of first reflux tank (21) * set correction value; The gas-liquid balance control specifically refers to: setting a reflux ratio coefficient value, wherein the reflux ratio is the ratio of the reflux flow rate to the flow rate of the material collected from the top of the column; calculating the reflux flow rate output value based on the calculated flow rate of the material collected from the top of the column; calculating the deviation between the actual temperature and the preset temperature or the deviation between the actual bottom liquid level and the preset bottom liquid level based on the actual temperature of the rectification section of rectification column I (1) or the actual bottom liquid level of rectification column I (1); calculating and controlling the reflux flow rate of the material returning to rectification column I (1): Return flow rate = Return flow rate output value + Second correction value; Second correction value = (Actual temperature - Preset temperature) / Temperature deviation setting * Setting correction value; Or, Return flow rate = Return flow rate output value + Third correction value; Third correction value = (Actual column bottom liquid level - Preset column bottom liquid level) / Column bottom liquid level deviation setting value * Setting correction value.

2. The fully automated separation control method for a distillation column system according to claim 1, characterized in that: The material balance control also includes controlling the bottom output of distillation column I (1) based on the actual bottom liquid level of distillation column I (1).

3. The fully automated separation control method for a distillation column system according to claim 1, characterized in that: When it is a multi-component impurity separation distillation column, the gas-liquid balance is controlled according to the actual temperature of the rectification section of the distillation column; when it is a single-component impurity separation distillation column, the gas-liquid balance is controlled according to the actual bottom liquid level of the distillation column.

4. The fully automated separation control method for a distillation column system according to claim 1, characterized in that: It also includes energy balance control for distillation column I (1), specifically referring to: controlling the circulating water volume according to the material outlet temperature after cooling by the first cooler (24) corresponding to distillation column I (1); and controlling the steam volume according to the material vapor phase temperature near the first reboiler (22) in the column bottom.

5. The fully automated separation control method for a distillation column system according to claim 4, characterized in that: The steam quantity is controlled based on the material vapor phase temperature in the first reboiler (22) of the tower, specifically including: Steam quantity = Set basic steam flow rate + fourth correction value; Fourth correction value = (Actual material vapor phase temperature near the first reboiler (22) of the tower bottom - Preset material vapor phase temperature near the first reboiler (22) of the tower bottom) / Vapor phase temperature deviation setting value * Setting correction value.

6. A fully automated separation control method for a distillation column system according to any one of claims 1 to 5, characterized in that: The distillation column system also includes a distillation column II (2) connected in series with distillation column I (1), and the control method also includes top-out control and reflux control of distillation column II (2); the top-out control specifically refers to controlling the top-out amount according to the top temperature of distillation column II (2), and the reflux control specifically refers to controlling the reflux flow rate according to the liquid level of the second reflux tank (33) corresponding to distillation column II (2).

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