Solvent recovery unit control system and method

Abstract

The invention provides a solvent recovery unit control system and method, and relates to the technical field of solvent processing, the system comprises a driving module, an operation control module and a parking module, the operation control module comprises a PID control unit and an advanced control and experience control unit; the driving module is used for checking and initializing operation parameters of a tower kettle in the solvent recovery unit in response to the driving request; the PID control unit is used for monitoring basic process parameters during operation of the tower kettle and adjusting the operation state of the tower kettle; the advanced control and experience control unit is used for monitoring unstable parameters during operation of the tower kettle and adjusting the operation state of the tower kettle; and the parking module is used for judging the parking type in response to the parking request and controlling the tower kettle to stop running according to a preset parking scheme. The automatic control of the solvent recovery unit is realized, and the stability of solvent recovery is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solvent treatment, and in particular to a control system and method for a solvent recovery unit. Background Art

[0002] Existing solvent recovery units usually require operators to manually adjust the tower kettle feed rate, tower top reflux rate, tower kettle output rate, tower kettle reboiler steam rate / hot oil and other operating points to realize the operation of the tower kettle. However, when faced with a complex solvent recovery unit, such as a solvent recovery unit with multiple tower kettles, the operator manually adjusts each parameter, monitors each parameter and adjusts the operation process at the same time. For example, if one of the parameters changes, it is necessary to determine the other parameter values ​​related to it based on experience and manually adjust them accordingly, resulting in frequent adjustments by the operator, high labor intensity, and the inability to guarantee the timeliness and simultaneity of the adjustment of each material. In addition, there are differences in the adjustment methods of different operators, resulting in low operational stability of the solvent recovery unit. Summary of the invention

[0003] The problem solved by the invention is how to improve the automation degree of solvent recovery, and then improve the stability of solvent recovery.

[0004] In order to solve the above problems, the present invention provides a solvent recovery unit control system and method.

[0005] In a first aspect, the present invention provides a solvent recovery unit control system, including a start-up module, an operation control module and a parking module, wherein the operation control module includes a PID control unit and an advanced control and experience control unit;

[0006] The start-up module is used to check the operating parameters of the tower kettle in the solvent recovery unit in response to the start-up request, and adjust the state of the tower kettle according to the check result to initialize the operating parameters and control the operation of the tower kettle;

[0007] The PID control unit is used to monitor the basic process parameters of the tower kettle during operation, and adjust the operation state of the tower kettle according to the basic process parameters and preset basic process conditions;

[0008] The advanced control and experience control unit is used to monitor the unstable parameters of the tower kettle during operation, and adjust the operation state of the tower kettle based on the unstable parameters and the preset stable conditions, and update the preset stable conditions using the experience scheme according to the adjusted unstable parameters of the tower kettle;

[0009] The parking module is used to respond to a parking request, determine the parking type corresponding to the parking request, and control the tower kettle to stop operating according to a preset parking plan based on the parking type.

[0010] The present invention is provided with a start-up module, which checks the operating parameters of the tower kettle after receiving a start-up request, adjusts the state of the tower kettle according to the inspection result, initializes the operating parameters, prepares for the tower kettle operation, and ensures the safety of subsequent tower kettle operation. A parking module is provided, which determines the corresponding parking type after receiving a parking request, and selects different parking schemes according to different parking types to control the tower kettle to stop operation, so as to cope with different working conditions and process operation requirements, increase parking flexibility, and reduce material and energy loss during parking. An operation control module is set, and the PID control unit is used to monitor the basic process parameters of the tower kettle during operation, and adjust the operation state of the tower kettle according to the basic process parameters and preset basic process conditions; the advanced control and experience control unit is used to monitor the unstable parameters of the tower kettle during operation, and adjust the operation state of the tower kettle based on the unstable parameters and preset stable conditions. According to the unstable parameters of the adjusted tower kettle, the preset stable conditions are updated using the experience scheme, and the PID control, advanced control and experience control are combined to realize the intelligent adjustment of the tower kettle operation, reduce the labor demand, improve the automation degree of solvent recovery, and realize the material inlet and outlet and energy balance of A, B, and C towers at the same time, and ensure the stable operation of the tower kettle. This embodiment realizes the automatic control of the solvent recovery unit from the whole process of starting, operation, and parking by setting the start-up module, the operation control module and the parking module. At the same time, it can also make adaptive adjustments to the situations occurring during operation, automatically overcome the interference that often occurs in the outside world, maintain the stable control of the solvent recovery unit, and effectively improve the stability of solvent recovery.

[0011] Optionally, the parking module is specifically used for:

[0012] The parking type is determined according to the parking time in the parking request and the preset parking time, and according to the parking type, the tower kettle is controlled to stop operating according to a full stop plan or a heat preservation plan.

[0013] Optionally, judging the parking type according to the parking time in the parking request and the preset parking time, and controlling the tower kettle to stop operating according to the parking type according to a full stop scheme or a heat preservation scheme includes:

[0014] When the parking time is less than or equal to the preset parking time, the parking type is judged to be short-term parking, and the tower kettle is controlled to stop running according to the insulation scheme, wherein the insulation scheme includes closing the cold and hot source valves of the tower kettle to a preset standby opening, closing the feed end and the discharge end of the tower kettle in sequence, and performing parameter initialization processing on the tower kettle;

[0015] When the parking time is greater than the preset parking time, the parking type is judged to be long-term parking, and the tower kettle is controlled to stop operating according to the full stop plan, wherein the full stop plan includes closing the feed end of the tower kettle, the cold and hot source valves of the tower kettle and the discharge end of the tower kettle in sequence, and initializing the parameters of the tower kettle.

[0016] Optionally, the number of the tower kettles is 3, and the three tower kettles are respectively A tower kettle, B tower kettle and C tower kettle, the feed end of the A tower kettle is connected to the mother liquor tank, the extraction end of the A tower kettle is connected to the feed end of the B tower kettle, the extraction end of the B tower kettle is connected to the feed end of the C tower kettle, and the defective product extraction end of the C tower kettle is connected to the feed end of the B tower kettle; the unstable parameters include the amount of material in the mother liquor tank, the temperature of the B tower kettle, the liquid level of the C tower kettle and the change amount of the defective product extraction end; the advanced control and experience control unit is specifically used for:

[0017] Based on the monitored material amount in the mother liquor tank, the adjusted feed amount of the A tower bottom is obtained according to the preset stable condition, and the A tower bottom is adjusted to feed according to the adjusted feed amount;

[0018] Based on the monitored temperature of the B tower kettle and the liquid level of the A tower kettle, the discharge amount to be adjusted at the extraction end of the A tower kettle is obtained according to the preset stable condition, and the extraction end of the A tower kettle is adjusted to discharge according to the discharge amount to be adjusted, so as to perform an initial adjustment on the temperature of the B tower kettle and adjust the liquid level of the A tower kettle;

[0019] Based on the monitored temperature of the B tower kettle after the initial adjustment and the change amount of the defective product extraction end, the main adjustment feed amount of the cold and hot source end of the B tower kettle is obtained according to the preset stable condition, and the cold and hot source end of the B tower kettle is adjusted to feed according to the main adjustment feed amount, so as to adjust the temperature of the B tower kettle again, wherein the cold and hot source end of the B tower kettle is used to be connected with the heat source of the B tower kettle and the reflux circuit of the B tower kettle, so as to adjust the temperature of the B tower kettle;

[0020] Based on the monitored liquid level of the C tower kettle, the feed change amount of the cold and hot source end of the C tower kettle is obtained according to the preset stable condition, and the cold and hot source end of the C tower kettle is adjusted to feed according to the feed change amount, wherein the cold and hot source end of the C tower kettle is used to connect with the heat source of the C tower kettle and the reflux loop of the C tower kettle to adjust the temperature of the C tower kettle;

[0021] According to the empirical scheme, the preset stable conditions are updated based on the current preset stable conditions, the temperature of the B tower bottom, the change in the defective product extraction end and the monitored top pressure of each tower bottom to obtain the preset stable conditions for the next cycle.

[0022] Optionally, the temperature of the B tower kettle includes a rectifying section temperature and a stripping section temperature, and the preset stability condition includes a preset temperature range, a preset safety liquid level, and a stripping section temperature target value; the step of obtaining a to-be-adjusted discharge amount of the withdrawal end of the A tower kettle based on the monitored temperature of the B tower kettle according to the preset stability condition and adjusting the withdrawal end of the A tower kettle to discharge according to the to-be-adjusted discharge amount, so as to initially adjust the temperature of the B tower kettle, and adjusting the liquid level of the A tower kettle includes:

[0023] When the monitored temperature of the distillation section continues to rise within a preset time and is greater than the upper limit of the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the temperature of the distillation section and the preset temperature range, a first discharge amount is obtained, and the withdrawal end of the A tower bottom is adjusted to discharge according to the first discharge amount;

[0024] When the monitored temperature of the stripping section continues to decrease within a preset time and is less than the lower limit of the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the stripping section temperature and the preset temperature range to obtain a second discharge amount, and the withdrawal end of the A tower bottom is adjusted to discharge according to the second discharge amount;

[0025] When the detected temperature of the distillation section and the detected temperature of the stripping section are both within the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the detected liquid level of the A tower bottom and the preset safety liquid level, the withdrawal amount is obtained, and the withdrawal end of the A tower bottom is adjusted to discharge according to the withdrawal amount.

[0026] Optionally, the temperature of the B tower kettle includes the distillation section temperature and the tower top temperature difference, the cold and hot source ends of the B tower kettle include the heat transfer oil end, the steam end and the reflux end, and the preset stability condition includes a preset temperature range and a target value of the stripping section temperature; based on the monitored temperature of the B tower kettle after the initial adjustment and the change amount of the defective product extraction end, obtaining the main adjustment feed amount of the cold and hot source end of the B tower kettle according to the preset stability condition and adjusting the cold and hot source end of the B tower kettle to feed according to the main adjustment feed amount, so as to adjust the temperature of the B tower kettle again includes:

[0027] When the monitored temperature of the rectifying section is within the preset temperature range, the main adjusted feed amount of the heat transfer oil end is determined according to the target temperature value of the stripping section, a first adjusted feed amount of the heat transfer oil end is obtained, and the heat transfer oil end is adjusted to feed according to the first adjusted feed amount;

[0028] When the monitored temperature of the rectification section continues to rise within a preset time and is greater than the upper limit of the preset temperature range, the main adjusted feed amounts of the heat transfer oil end and the reflux end are determined according to the temperature of the rectification section and the preset temperature range, a second adjusted feed amount of the heat transfer oil end and a third adjusted feed amount of the reflux end are obtained, and the heat transfer oil end is adjusted to feed according to the second adjusted feed amount and the reflux end is adjusted to feed according to the third adjusted feed amount;

[0029] When the monitored sensitive temperature of the distillation section is greater than the upper limit of the preset temperature range and is maintained for the preset time, the top temperature difference is monitored and obtained. When the top temperature difference exceeds the preset temperature difference upper limit, the main adjustment feed amount of the reflux end is determined according to the top temperature difference, and the fourth adjustment feed amount of the reflux end is obtained. The reflux end is adjusted to feed according to the fourth adjustment feed amount.

[0030] Optionally, the preset stability condition is updated according to the current preset stability condition, the temperature of the B tower, the change in the defective product extraction end, and the monitored tower top pressure of each tower, and the preset stability condition for the next cycle is obtained according to the empirical scheme, including:

[0031] Obtaining a first product of a preset factor and the current tower top pressure, and a second product of a change in the defective product extraction end and the sensitive temperature of the rectification section, and determining a ratio of the first product to the second product;

[0032] The sum of the stripping section temperature target value of the current cycle and the ratio is obtained to obtain the stripping section temperature target value of the next cycle.

[0033] Optionally, the empirical solution is expressed using a first formula, which is expressed as:

[0034] T (i+1) =T (i) +k*P D(i) / (△F*T),

[0035] Where i represents the i-th cycle, T (i+1) represents the target temperature value of the stripping section in the i+1th cycle, T (i) represents the target temperature value of the stripping section in the i-th cycle, k represents the preset factor, P D(i) represents the tower top pressure in the ith cycle, ΔF represents the change in the defective product extraction end, and T represents the sensitive temperature of the distillation section.

[0036] Optionally, the preset stability condition includes a preset mother liquor level range; the step of obtaining the adjusted feed amount of the A tower bottom according to the preset stability condition based on the monitored material amount of the mother liquor tank and adjusting the A tower bottom to feed according to the adjusted feed amount includes:

[0037] When the monitored material amount in the mother liquor tank exceeds the upper limit of the preset mother liquor level range, a first adjusted feed amount of the A tower bottom is obtained according to the material amount in the mother liquor tank and the preset mother liquor level range, and the A tower bottom is adjusted to feed according to the first adjusted feed amount;

[0038] When the monitored material amount in the mother liquor tank is lower than the lower limit of the preset mother liquor level range, the second adjusted feed amount of the A tower bottom is obtained according to the material amount in the mother liquor tank and the preset mother liquor level range, and the A tower bottom is adjusted to feed according to the second adjusted feed amount.

[0039] In a second aspect, the present invention provides a solvent recovery unit control method, comprising:

[0040] In response to a start-up request, using a start-up module to check the operating parameters of a tower bottom in a solvent recovery unit, adjusting the state of the tower bottom according to the check result to initialize the operating parameters, and controlling the operation of the tower bottom;

[0041] Using a PID control unit, the basic process parameters of the tower kettle during operation are monitored, and the operating state of the tower kettle is adjusted according to the basic process parameters and preset basic process conditions;

[0042] Using an advanced control and experience control unit, the unstable parameters of the tower kettle during operation are monitored, and the operating state of the tower kettle is adjusted based on the unstable parameters and preset stable conditions, and the preset stable conditions are updated using an experience scheme according to the adjusted unstable parameters of the tower kettle;

[0043] In response to a parking request, a parking module is used to determine a parking type corresponding to the parking request, and based on the parking type, the tower kettle is controlled to stop operating according to a preset parking plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a structural schematic diagram of a control system of a solvent recovery unit according to an embodiment of the present invention;

[0045] Figure 2 Schematic diagram of the structure of a solvent recovery unit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0047] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0048] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0049] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0050] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0051] In view of the problems existing in the above-mentioned related technologies, this embodiment provides a solvent recovery unit control system and method.

[0052] like Figure 1 As shown, a solvent recovery unit control system provided by an embodiment of the present invention includes a start-up module, an operation control module and a parking module, wherein the operation control module includes a PID control unit and an advanced control and experience control unit, and the start-up module, the operation control module and the parking module are respectively connected to the tower bottom for monitoring the operating status of the tower bottom.

[0053] Specifically, the solvent recovery unit control system can be applied to a solvent recovery unit with a single reactor or a solvent recovery unit with multiple reactors. The solvent recovery unit control system of this embodiment is applied to a solvent recovery unit with three reactors, such as Figure 2 As shown, the start-up module, the operation control module and the parking module are respectively connected to the A tower kettle, the B tower kettle and the C tower kettle, and are used to monitor the operating status of the A tower kettle, the B tower kettle and the C tower kettle respectively.

[0054] The start-up module is used to check the operating parameters of the tower bottom in the solvent recovery unit in response to the start-up request, adjust the state of the tower bottom according to the inspection result to initialize the operating parameters, and control the operation of the tower bottom.

[0055] Specifically, the start-up module responds to the start-up request issued by the staff, first checks the operating parameters in the tower kettle, and adjusts the state of the tower kettle according to the inspection results to initialize the parameters, so that the tower kettle is ready for solvent recovery and improves the solvent recovery efficiency. Figure 2 Taking the solvent recovery unit as an example, the process of starting the module to control the operation of the tower kettle includes:

[0056] The start-up module starts the A tower in response to the start-up request:

[0057] (1) Check whether the liquid level in the kettle of tower A is greater than the lower limit of the liquid level in the kettle of tower A. If so, open the flash tank temperature circuit of the kettle of tower A to increase the temperature in the kettle of tower A to keep the temperature in the kettle of tower A stable; otherwise, issue an early warning;

[0058] (2) Check whether the temperature of the kettle of tower A is greater than the lower temperature limit of the kettle of tower A. If so, open the reflux of the kettle of tower A to maintain the heat balance in the tower; otherwise, continue to wait until the temperature meets the requirements;

[0059] (3) When the reflux loop of the kettle of tower A is opened, the top extraction and reflux tank liquid level adjustment loop of the kettle of tower A is opened ( Figure 2 The top of the kettle of tower A is connected to the right cooling water valve and the loop of reflux tank A) to control the liquid level of reflux tank of tower A to be stable;

[0060] …

[0061] (n) Initialize the parameters of Tower A.

[0062] The start-up module starts the B tower in response to the start-up request:

[0063] (1) Open the vacuum valve of the kettle of Tower B to maintain the negative pressure in the kettle of Tower B;

[0064] (2) Check whether the pressure at the top of the kettle of tower B is less than the upper pressure limit of the kettle of tower B, and whether the liquid level in the kettle of tower B is greater than the lower liquid level limit of the kettle of tower B. If so, turn on the heat source of the kettle of tower B (such as the B evaporator circuit and the heat transfer oil feed pump) to increase the temperature in the kettle of tower B to keep the temperature in the kettle of tower B stable; otherwise, issue an early warning;

[0065] (3) Start the protection program (e.g., thermal oil feed pump protection program);

[0066] …

[0067] (n) Initialize the parameters of tower B.

[0068] The start-up module starts the C tower in response to the start-up request:

[0069] (1) Open the vacuum valve of the kettle of Tower C to maintain the negative pressure in the kettle of Tower C;

[0070] (2) Check whether the top pressure of the C tower kettle is less than the upper pressure limit of the C tower kettle. If so, open the cold source circuit connected to the top of the C tower kettle (such as Figure 2 The cooling water valve connected to the top of the C tower kettle and the circuit of the C finished product tank) are used to increase the temperature in the C tower kettle to keep the temperature in the C tower kettle stable; otherwise, an early warning is issued;

[0071] (3) Check whether the liquid level in the kettle of tower C is greater than the lower limit of the liquid level of the kettle of tower C. If so, turn on the heat source of the kettle of tower C (such as the evaporator pump connected to the kettle of tower C) to increase the temperature in the kettle of tower C. Otherwise, continue to wait until the liquid level meets the requirements;

[0072] …

[0073] (n) Initialize the C tower parameters.

[0074] The PID control unit is used to monitor the basic process parameters when the tower bottom is in operation, and adjust the operation state of the tower bottom according to the basic process parameters and preset basic process conditions.

[0075] Specifically, when the tower kettle is in operation, the basic process parameters of the tower kettle, such as the pressure in the tower kettle and the liquid level of the reflux tank in the tower kettle cold source reflux loop, have certain operating rules. For example, a PID algorithm can be set to adjust the basic process parameters to ensure that the basic process parameters of the tower kettle meet the preset basic process conditions during the operation of the tower kettle, providing a basis for the operation of the tower kettle. Among them, the preset basic process parameters can be set according to the characteristics of the selected tower kettle device itself, and are not specifically limited here.

[0076] The advanced control and experience control unit is used to monitor the unstable parameters of the tower bottom during operation, and adjust the operating state of the tower bottom based on the unstable parameters and preset stable conditions, and update the preset stable conditions using an experience scheme based on the adjusted unstable parameters of the tower bottom.

[0077] Specifically, facing a more complex solvent recovery unit, such as Figure 2 In a solvent recovery unit with three towers, during its operation, the change of one parameter may cause unbalanced parameters in the subsequent towers, for example, Figure 2 As shown in the figure, when the feed amount of the A reactor changes, the feed amount and feed composition of the B reactor will change significantly, causing imbalance in the feed, inlet and outlet parameters of the cold and heat sources in the B reactor (into the evaporator, cooling water reflux loop, etc.), affecting the solvent recovery efficiency and even causing production accidents. Combined with the functions of each reactor in the solvent recovery unit, the unstable parameters are marked to Figure 2 Take the solvent recovery unit in the reactor as an example, where the unstable parameters include the amount of material in the mother liquor tank, the temperature of the B tower, the liquid level of the C tower, the change in the defective product extraction end, etc. Advanced Process Control (APC) is used to calculate the unstable parameters in the subsequent operation process based on the real-time monitored unstable parameters and the preset stable conditions, and control the towers to operate according to the calculated unstable parameters to ensure stable operation of each tower. For example, if Figure 2 If the feed amount of the A tower kettle changes, the APC is used to obtain the temperature of the B tower kettle, the liquid level of the C tower kettle, the change in the defective product extraction end, etc. corresponding to the changed feed amount of the A tower kettle, and the stable operation of the B tower kettle and the C tower kettle is controlled according to the updated temperature of the B tower kettle, the liquid level of the C tower kettle, the change in the defective product extraction end, etc. It should be noted that the preset stable conditions may include a safety range corresponding to unstable parameters, a tower kettle operation standard, or a situation where the tower kettle is unstable, such as the temperature range of the B tower kettle, the target value of the stripping section temperature in the B tower kettle, and the temperature of the B tower kettle exceeds the range for a certain period of time, causing the B tower kettle to operate unstable.

[0078] When the unstable parameters change, the operating parameters of the subsequent tower kettle operation will also change accordingly. For example, the feed amount of tower A kettle increases or decreases, resulting in a large change in the feed amount and feed type of tower B kettle. The temperature target value of the distillation section in the tower B kettle that meets the current parameter operation will also change. If the current tower kettle operation is still monitored according to the original preset stable conditions, misjudgment of tower kettle operation failures may occur, affecting the solution recovery process. Therefore, after updating the unstable parameters, the preset stable conditions should also be updated based on the current unstable parameters (i.e., operating conditions).

[0079] The parking module is used to determine the parking type in response to the parking request, and based on the parking type, control the tower kettle to stop operating according to a preset parking plan.

[0080] Specifically, the parking types may include short-term parking, long-term parking, intermittent parking and the like. Short-term parking means that the solvent recovery unit is paused for a period of time and then the solvent recovery unit is started again. Long-term parking means that the solvent recovery unit is stopped and will not be started for a long period of time. Intermittent parking means that the solvent recovery unit is started after being paused for a period of time, and this step is executed cyclically. The existing technical means will shut down the operation of the tower kettle in sequence after receiving a parking request, and restart the tower kettle to perform preheating and other operations after receiving the next start-up request. However, when this method is used for short-term parking or intermittent parking, the tower kettle repeatedly stops, starts, preheats and heats up the temperature, which will generate a large amount of resource consumption and operating loss of the tower kettle itself. In order to avoid this phenomenon, the parking module of this embodiment will determine the parking type according to the parking request, such as parking time, parking demand, etc., and control the tower kettle to stop operating when calling the corresponding preset parking plan. For example, if the parking type is intermittent parking and the interval time is relatively short, then when the tower kettle is stopped, the lowest operating state of the cold and heat source circuits of each tower kettle is retained, that is, the temperature in the tower kettle is retained, so as to avoid resource loss caused by the need to preheat and heat up again when restarting the tower kettle.

[0081] Optionally, the parking module is specifically used for:

[0082] The parking type is determined according to the parking time in the parking request and the preset parking time, and according to the parking type, the tower kettle is controlled to stop operating according to a full stop plan or a heat preservation plan.

[0083] Specifically, in this embodiment, the parking type is mainly divided into short-term parking and long-term parking according to the parking time, and is divided according to the preset parking time. The preset parking time is determined according to the operating conditions of the tower kettle and the resource loss. For example, it takes 1 minute to preheat the tower kettle to the target operating temperature, and the resource loss generated is x. The resource loss generated by the tower kettle running at the lowest cold and heat source circuit for a minutes is x, then the preset parking time can be set to a minute.

[0084] When the parking time is less than or equal to the preset parking time, the parking type is judged to be the short-term parking, and the tower kettle is controlled to stop running according to the insulation scheme, wherein the insulation scheme includes closing the cold and hot source valves of the tower kettle to a preset standby opening, closing the feed end and the discharge end of the tower kettle in turn, and performing parameter initialization processing on the tower kettle.

[0085] When the parking time is greater than the preset parking time, the parking type is judged to be long-term parking, and the tower kettle is controlled to stop operating according to the full stop plan, wherein the full stop plan includes closing the feed end of the tower kettle, the cold and hot source valves of the tower kettle and the discharge end of the tower kettle in sequence, and initializing the parameters of the tower kettle.

[0086] This embodiment determines the parking type and adopts a corresponding parking plan to reduce the resource loss caused by repeated parking and the self-loss caused by repeated starting and stopping of the tower kettle, thereby increasing the service life of the tower kettle.

[0087] Alternatively, if Figure 2 As shown, the number of the tower kettles in the solvent recovery unit used in this embodiment is 3, and the three tower kettles are respectively A tower kettle, B tower kettle and C tower kettle, the feed end of the A tower kettle is connected to the mother liquor tank, the extraction end of the A tower kettle is connected to the feed end of the B tower kettle, the extraction end of the B tower kettle is connected to the feed end of the C tower kettle, the defective extraction end of the C tower kettle is connected to the feed end of the B tower kettle, the cold and hot source end of the B tower kettle includes a heat transfer oil end connected to a heat transfer oil source, a steam end connected to the B evaporation tank, and a reflux end connected to a reflux loop (including a cooling water valve and a stratifier), the cold and hot source end of the A tower kettle includes a steam end connected to an A flash tank, a reflux end connected to a reflux loop (including a cooling water valve and an A reflux tank), and the cold and hot source end of the C tower kettle includes a steam end connected to a steam source and a reflux end connected to a reflux loop (including a cooling water valve and a C finished product tank).

[0088] The preset stable conditions include a preset temperature range, a preset safety liquid level, a stripping section temperature target value and a preset mother liquor level range; the unstable parameters include the amount of material in the mother liquor tank, the temperature of the B tower, the liquid level of the C tower and the change in the defective product extraction end. The advanced control and experience control unit are specifically used for:

[0089] Based on the monitored material amount in the mother liquor tank, the adjusted feed amount of the A tower bottom is obtained according to the preset stable condition and the A tower bottom is adjusted to feed according to the adjusted feed amount.

[0090] When the monitored material amount in the mother liquor tank exceeds the upper limit of the preset mother liquor level range, the first adjusted feed amount of the A tower bottom is obtained according to the material amount in the mother liquor tank and the preset mother liquor level range, and the A tower bottom is adjusted to feed according to the first adjusted feed amount.

[0091] When the monitored material amount in the mother liquor tank is lower than the lower limit of the preset mother liquor level range, the second adjusted feed amount of the A tower bottom is obtained according to the material amount in the mother liquor tank and the preset mother liquor level range, and the A tower bottom is adjusted to feed according to the second adjusted feed amount.

[0092] Specifically, when the solvent recovery unit is recovering the solvent, it is necessary to constantly monitor the mother liquor in the mother liquor tank, and adjust the processing load of the solvent recovery unit, i.e., the feed amount of the A tower bottom, according to the liquid level of the mother liquor, to prevent the mother liquor stored in the mother liquor tank from overflowing due to excessive mother liquor. The advanced control and experience control unit monitors the amount of material in the mother liquor tank in real time, and adjusts the load of the A tower bottom, i.e., the feed amount of the A tower bottom, according to the amount of material and the preset stable conditions, to achieve automatic adjustment of the tower bottom load to avoid overflow of the mother liquor in the mother liquor tank.

[0093] Based on the monitored temperature of the B tower kettle and the liquid level of the A tower kettle, the discharge amount to be adjusted at the withdrawal end of the A tower kettle is obtained according to the preset stable conditions and the withdrawal end of the A tower kettle is adjusted to discharge according to the discharge amount to be adjusted, so as to make an initial adjustment to the temperature of the B tower kettle and adjust the liquid level of the A tower kettle.

[0094] Specifically, the unstable parameter A tower kettle liquid level is mainly determined by the A tower kettle output (i.e., the B tower kettle feed), and when the A tower kettle output is used to affect the A tower kettle liquid level, since the B tower kettle is sensitive to the feed amount, a slight change in the feed amount may cause a huge change in the temperature in the B tower kettle, so it is necessary to always observe the change in the B tower kettle temperature to prevent the B tower kettle from being disturbed by the feed amount or feed components of the B tower kettle. Therefore, the temperature of the B tower kettle is initially adjusted according to the output of the A tower kettle to avoid the temperature of the B tower kettle being too high during subsequent operation, which may cause accidents. The temperature of the B tower kettle includes the temperature of the rectifying section and the temperature of the stripping section.

[0095] When the monitored temperature of the distillation section continues to rise within a preset time and is greater than the upper limit of the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the distillation section temperature and the preset temperature range, and a first discharge amount is obtained, and the withdrawal end of the A tower bottom is adjusted to discharge according to the first discharge amount.

[0096] For example, when the temperature of the distillation section of the B tower kettle rises rapidly and exceeds its upper limit for 5 minutes, the APC is used to calculate the first discharge amount at the withdrawal end of the A tower kettle required to reduce the current distillation section temperature to the preset temperature range based on the current distillation section temperature. The withdrawal amount of the A tower kettle is quickly increased to the first discharge amount, so that the sensitive temperature of the distillation section drops rapidly.

[0097] When the monitored temperature of the distillation section continues to decrease within a preset time and is less than the lower limit of the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the distillation section temperature and the preset temperature range, and a second discharge amount is obtained, and the withdrawal end of the A tower bottom is adjusted to discharge according to the second discharge amount.

[0098] For example, when the temperature of the distillation section of the bottom of tower B drops rapidly and exceeds its lower limit for 5 minutes, the APC is used to calculate the second discharge amount at the output end of the bottom of tower A that needs to be adjusted to increase the current temperature of the distillation section to the preset temperature range, based on the current temperature of the distillation section. The output amount of the bottom of tower A is quickly reduced to the second discharge amount, so that the sensitive temperature of the distillation section can be quickly restored.

[0099] When the detected temperature of the distillation section and the detected temperature of the stripping section are both within the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower kettle is determined according to the detected liquid level of the A tower kettle and the preset safety liquid level, the withdrawal amount is obtained, and the withdrawal end of the A tower kettle is adjusted to discharge according to the withdrawal amount. Specifically, when the withdrawal amount of the A tower kettle does not affect the temperature of the B tower kettle, the liquid level of the A tower kettle can be adjusted according to the preset safety liquid level. It should be noted that the preset safety liquid level in this embodiment is the highest liquid level when the A tower kettle, the B tower kettle and the C tower kettle are in safe operation.

[0100] Based on the monitored temperature of the B tower kettle after the initial adjustment and the change in the defective product extraction end, the main adjustment feed amount of the cold and hot source end of the B tower kettle is obtained according to the preset stable condition, and the cold and hot source end of the B tower kettle is adjusted to feed according to the main adjustment feed amount to adjust the temperature of the B tower kettle again, wherein the cold and hot source end of the B tower kettle is used to be connected to the heat source of the B tower kettle and the reflux loop of the B tower kettle to adjust the temperature of the B tower kettle.

[0101] Specifically, in Figure 2 In the solvent recovery unit shown, the heat source of the B tower kettle is the B evaporator and the heat transfer oil end, wherein the B evaporator is connected to the extraction end of the A tower kettle, and the output of the A tower kettle is evaporated and then input into the B tower kettle. The defective sampling end of the C tower kettle is connected to the B evaporator of the B tower kettle, and the defective products generated after the operation of the C tower kettle are used as the B evaporator processing materials of the B tower kettle and input into the B tower kettle for processing. The output of the defective sampling end of the C tower kettle is usually 50% of the sampling amount of the A tower kettle. At this time, the feed amount of the B tower kettle changes greatly compared to the extraction amount of the A tower kettle alone, and the temperature in the B tower kettle also changes greatly. Therefore, the temperature of the B tower kettle needs to be adjusted again to ensure the normal operation of the B tower kettle. The specific situations include the following:

[0102] When the monitored temperature of the rectifying section is within the preset temperature range, the main adjustment feed amount of the heat transfer oil end is determined according to the target temperature value of the stripping section, a first adjustment feed amount of the heat transfer oil end is obtained, and the heat transfer oil end is adjusted to feed according to the first adjustment feed amount, so as to control the temperature of the stripping section near the target temperature value of the stripping section to ensure stable operation;

[0103] When the monitored temperature of the distillation section continues to rise within a preset time and is greater than the upper limit of the preset temperature range, the main adjustment feed amounts of the heat transfer oil end and the reflux end are determined according to the temperature of the distillation section and the preset temperature range, and the second adjustment feed amount of the heat transfer oil end and the third adjustment feed amount of the reflux end are obtained. The heat transfer oil end is adjusted to feed according to the second adjustment feed amount and the reflux end is adjusted to feed according to the third adjustment feed amount, so that the temperature of the distillation section drops rapidly.

[0104] When the monitored sensitive temperature of the distillation section is greater than the upper limit of the preset temperature range and is maintained for the preset time, the top temperature difference is monitored, and when the top temperature difference exceeds the preset temperature difference upper limit, the main adjustment feed amount of the reflux end is determined according to the top temperature difference and the preset top temperature difference, and the fourth adjustment feed amount of the reflux end is obtained, and the reflux end is adjusted to feed according to the fourth adjustment feed amount. It should be noted that when the monitored sensitive temperature of the distillation section is greater than the upper limit of the preset temperature range and is maintained for the preset time, the heavy component material vaporized from the bottom of the tower is not fully contacted and transferred with the top reflux, which will cause the top temperature difference to rise rapidly. Therefore, when the sensitive temperature of the distillation section is greater than the upper limit of the preset temperature range and is maintained for the preset time, its top temperature difference usually also reaches the upper limit.

[0105] Based on the monitored liquid level of the C tower kettle, the feed change amount of the cold and hot source end of the C tower kettle is obtained according to the preset stable condition, and the cold and hot source end of the C tower kettle is adjusted to feed according to the feed change amount, so as to prevent the C tower kettle liquid level from exceeding the upper limit for too long, causing damage to the C tower kettle. The cold and hot source end of the C tower kettle is used to connect with the heat source of the C tower kettle and the reflux circuit of the C tower kettle to adjust the temperature of the C tower kettle. Figure 2 In the solvent recovery unit shown, the heat source of the C tower kettle is steam, and the reflux loop of the C tower kettle is a loop formed by the cooling water valve and the C finished product tank.

[0106] According to the empirical scheme, the preset stable conditions are updated based on the current preset stable conditions, the temperature of the B tower bottom, the change in the defective product extraction end and the monitored top pressure of each tower bottom to obtain the preset stable conditions for the next cycle.

[0107] Specifically, because the feed amount and feed composition of the bottom of tower B vary greatly, causing the "optimal" temperature of the stripping section to change, it is necessary to recalculate the target value of the stripping section in the preset stable condition.

[0108] Optionally, a first product of a preset factor and the current tower top pressure, and a second product of a change in the defective product extraction end and a sensitive temperature of the rectification section are obtained, and a ratio of the first product to the second product is determined;

[0109] The sum of the stripping section temperature target value of the current cycle and the ratio is obtained to obtain the stripping section temperature target value of the next cycle.

[0110] Optionally, the empirical solution is expressed using a first formula, which is expressed as:

[0111] T (i+1) =T (i) +k*P D(i) / (△F*T),

[0112] Where i represents the i-th cycle, T (i+1) represents the target temperature value of the stripping section in the i+1th cycle, T (i) represents the target temperature value of the stripping section in the i-th cycle, k represents the preset factor, P D(i) represents the tower top pressure in the ith cycle, ΔF represents the change in the defective product extraction end, and T represents the sensitive temperature of the distillation section.

[0113] In a second aspect, an embodiment of the present invention further discloses a solvent recovery unit control method, comprising:

[0114] In response to a start-up request, using a start-up module to check the operating parameters of a tower bottom in a solvent recovery unit, adjusting the state of the tower bottom according to the check result to initialize the operating parameters, and controlling the operation of the tower bottom;

[0115] Using a PID control unit, the basic process parameters of the tower kettle during operation are monitored, and the operating state of the tower kettle is adjusted according to the basic process parameters and preset basic process conditions;

[0116] Using an advanced control and experience control unit, the unstable parameters of the tower kettle during operation are monitored, and the operating state of the tower kettle is adjusted based on the unstable parameters and preset stable conditions, and the preset stable conditions are updated using an experience scheme according to the adjusted unstable parameters of the tower kettle;

[0117] In response to the parking request, the parking module is used to determine the parking type, and based on the parking type, the tower kettle is controlled to stop operating according to a preset parking plan.

[0118] In this embodiment, in response to the start-up request, the start-up module is used to check the operating parameters of the tower kettle in the solvent recovery unit, and the state of the tower kettle is adjusted according to the inspection result to initialize the operating parameters, control the operation of the tower kettle, and ensure the safety of the tower kettle start-up. In response to the parking request, the parking module is used to determine the parking type, and based on the parking type, the tower kettle is controlled to stop operating according to the preset parking plan. Different parking plans are used to control the tower kettle to stop operating according to the parking type to cope with different working conditions and process operation requirements, while reducing material and energy losses during the parking process. The PID control unit is used to monitor the basic process parameters of the tower kettle during operation, and the operating state of the tower kettle is adjusted according to the basic process parameters and preset basic process conditions; the advanced control and experience control unit is used to monitor the unstable parameters of the tower kettle during operation, and the operating state of the tower kettle is adjusted based on the unstable parameters and preset stable conditions. According to the unstable parameters of the adjusted tower kettle, the preset stable conditions are updated using the experience scheme. The method combining PID control, cash control and experience control is adopted to realize intelligent adjustment of the tower kettle operation, reduce labor demand, improve the degree of automation of solvent recovery, and simultaneously realize the material inlet and outlet and energy balance of A, B, and C tower kettles, ensure the stable operation of the tower kettle, and effectively improve the stability of solvent recovery.

[0119] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A solvent recovery unit control system, characterized in that: It includes a driving module, an operation control module and a parking module, wherein the operation control module includes a PID control unit and an advanced control and experience control unit; The start-up module is used to check the operating parameters of the tower kettle in the solvent recovery unit in response to the start-up request, and adjust the state of the tower kettle according to the check result to initialize the operating parameters and control the operation of the tower kettle; The PID control unit is used to monitor the basic process parameters of the tower kettle during operation, and adjust the operation state of the tower kettle according to the basic process parameters and preset basic process conditions; The advanced control and experience control unit is used to monitor the unstable parameters of the tower kettle during operation, and adjust the operation state of the tower kettle based on the unstable parameters and the preset stable conditions, and update the preset stable conditions using the experience scheme according to the adjusted unstable parameters of the tower kettle; The parking module is used to respond to a parking request, determine the parking type corresponding to the parking request, and control the tower kettle to stop operating according to a preset parking plan based on the parking type.

2. The solvent recovery unit control system according to claim 1, characterized in that: The parking module is specifically used for: The parking type is determined according to the parking time in the parking request and the preset parking time, and according to the parking type, the tower kettle is controlled to stop operating according to a full stop plan or a heat preservation plan.

3. The solvent recovery unit control system according to claim 1, characterized in that: The step of determining the parking type according to the parking time and the preset parking time in the parking request, and controlling the tower kettle to stop operation according to the full stop scheme or the insulation scheme according to the parking type includes: When the parking time is less than or equal to the preset parking time, the parking type is judged to be short-term parking, and the tower kettle is controlled to stop running according to the insulation scheme, wherein the insulation scheme includes closing the cold and hot source valves of the tower kettle to a preset standby opening, closing the feed end and the discharge end of the tower kettle in sequence, and performing parameter initialization processing on the tower kettle; When the parking time is greater than the preset parking time, the parking type is judged to be long-term parking, and the tower kettle is controlled to stop operating according to the full stop plan, wherein the full stop plan includes closing the feed end of the tower kettle, the cold and hot source valves of the tower kettle and the discharge end of the tower kettle in sequence, and initializing the parameters of the tower kettle.

4. The solvent recovery unit control system according to claim 1, characterized in that: The number of the tower kettles is 3, and the three tower kettles are respectively A tower kettle, B tower kettle and C tower kettle. The feed end of the A tower kettle is connected to the mother liquor tank, the extraction end of the A tower kettle is connected to the feed end of the B tower kettle, the extraction end of the B tower kettle is connected to the feed end of the C tower kettle, and the defective product extraction end of the C tower kettle is connected to the feed end of the B tower kettle; the unstable parameters include the amount of material in the mother liquor tank, the temperature of the B tower kettle, the liquid level of the C tower kettle and the change amount of the defective product extraction end; the advanced control and experience control unit is specifically used for: Based on the monitored material amount in the mother liquor tank, the adjusted feed amount of the A tower bottom is obtained according to the preset stable condition, and the A tower bottom is adjusted to feed according to the adjusted feed amount; Based on the monitored temperature of the B tower kettle and the liquid level of the A tower kettle, the discharge amount to be adjusted at the extraction end of the A tower kettle is obtained according to the preset stable condition, and the extraction end of the A tower kettle is adjusted to discharge according to the discharge amount to be adjusted, so as to perform an initial adjustment on the temperature of the B tower kettle and adjust the liquid level of the A tower kettle; Based on the monitored temperature of the B tower kettle after the initial adjustment and the change amount of the defective product extraction end, the main adjustment feed amount of the cold and hot source end of the B tower kettle is obtained according to the preset stable condition, and the cold and hot source end of the B tower kettle is adjusted to feed according to the main adjustment feed amount, so as to adjust the temperature of the B tower kettle again, wherein the cold and hot source end of the B tower kettle is used to be connected with the heat source of the B tower kettle and the reflux circuit of the B tower kettle, so as to adjust the temperature of the B tower kettle; Based on the monitored liquid level of the C tower kettle, the feed change amount of the cold and hot source end of the C tower kettle is obtained according to the preset stable condition, and the cold and hot source end of the C tower kettle is adjusted to feed according to the feed change amount, wherein the cold and hot source end of the C tower kettle is used to connect with the heat source of the C tower kettle and the reflux loop of the C tower kettle to adjust the temperature of the C tower kettle; According to the empirical scheme, the preset stable conditions are updated based on the current preset stable conditions, the temperature of the B tower bottom, the change in the defective product extraction end and the monitored top pressure of each tower bottom to obtain the preset stable conditions for the next cycle.

5. The solvent recovery unit control system according to claim 4, characterized in that: The temperature of the B tower kettle includes the temperature of the rectifying section and the temperature of the stripping section, and the preset stable condition includes a preset temperature range, a preset safe liquid level and a target value of the stripping section temperature; based on the monitored temperature of the B tower kettle, the discharge amount to be adjusted at the withdrawal end of the A tower kettle is obtained according to the preset stable condition, and the withdrawal end of the A tower kettle is adjusted to discharge according to the discharge amount to be adjusted, so as to perform an initial adjustment on the temperature of the B tower kettle, and the liquid level of the A tower kettle is adjusted, comprising: When the monitored temperature of the distillation section continues to rise within a preset time and is greater than the upper limit of the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the temperature of the distillation section and the preset temperature range, a first discharge amount is obtained, and the withdrawal end of the A tower bottom is adjusted to discharge according to the first discharge amount; When the monitored temperature of the stripping section continues to decrease within a preset time and is less than the lower limit of the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the stripping section temperature and the preset temperature range to obtain a second discharge amount, and the withdrawal end of the A tower bottom is adjusted to discharge according to the second discharge amount; When the detected temperature of the distillation section and the detected temperature of the stripping section are both within the preset temperature range, the discharge amount to be adjusted at the withdrawal end of the A tower bottom is determined according to the detected liquid level of the A tower bottom and the preset safety liquid level, the withdrawal amount is obtained, and the withdrawal end of the A tower bottom is adjusted to discharge according to the withdrawal amount.

6. The solvent recovery unit control system according to claim 4, characterized in that: The temperature of the B tower kettle includes the temperature of the rectification section and the temperature difference of the tower top, the cold and heat source ends of the B tower kettle include the heat transfer oil end, the steam end and the reflux end, and the preset stability condition includes a preset temperature range and a target value of the stripping section temperature; based on the monitored temperature of the B tower kettle after the initial adjustment and the change amount of the defective product extraction end, the main adjustment feed amount of the cold and heat source end of the B tower kettle is obtained according to the preset stability condition, and the cold and heat source end of the B tower kettle is adjusted to feed according to the main adjustment feed amount, so as to adjust the temperature of the B tower kettle again, including: When the monitored temperature of the rectifying section is within the preset temperature range, the main adjusted feed amount of the heat transfer oil end is determined according to the target temperature value of the stripping section, a first adjusted feed amount of the heat transfer oil end is obtained, and the heat transfer oil end is adjusted to feed according to the first adjusted feed amount; When the monitored temperature of the rectification section continues to rise within a preset time and is greater than the upper limit of the preset temperature range, the main adjusted feed amounts of the heat transfer oil end and the reflux end are determined according to the temperature of the rectification section and the preset temperature range, a second adjusted feed amount of the heat transfer oil end and a third adjusted feed amount of the reflux end are obtained, and the heat transfer oil end is adjusted to feed according to the second adjusted feed amount and the reflux end is adjusted to feed according to the third adjusted feed amount; When the monitored sensitive temperature of the distillation section is greater than the upper limit of the preset temperature range and is maintained for the preset time, the top temperature difference is monitored and obtained. When the top temperature difference exceeds the preset temperature difference upper limit, the main adjustment feed amount of the reflux end is determined according to the top temperature difference, and the fourth adjustment feed amount of the reflux end is obtained. The reflux end is adjusted to feed according to the fourth adjustment feed amount.

7. The solvent recovery unit control system according to claim 6, characterized in that: According to the empirical scheme, the preset stable condition is updated according to the current preset stable condition, the temperature of the B tower, the change amount of the defective product extraction end and the monitored tower top pressure of each tower, and the preset stable condition of the next cycle is obtained: Obtaining a first product of a preset factor and the current tower top pressure, and a second product of a change in the defective product extraction end and the sensitive temperature of the rectification section, and determining a ratio of the first product to the second product; The sum of the stripping section temperature target value of the current cycle and the ratio is obtained to obtain the stripping section temperature target value of the next cycle.

8. The solvent recovery unit control system according to claim 7, characterized in that: The empirical scheme is expressed by a first formula, which is: T (i+1) =T (i) +k*P D(i) / (△F*T), Where i represents the i-th cycle, T (i+1) represents the target temperature value of the stripping section in the i+1th cycle, T (i) represents the target temperature value of the stripping section in the i-th cycle, k represents the preset factor, P D(i) represents the tower top pressure in the ith cycle, ΔF represents the change in the defective product extraction end, and T represents the sensitive temperature of the distillation section.

9. The solvent recovery unit control system according to claim 4, characterized in that: The preset stability condition includes a preset mother liquor level range; the adjusting feed amount of the A tower bottom is obtained according to the preset stability condition based on the monitored material amount of the mother liquor tank, and the A tower bottom is adjusted to feed according to the adjusted feed amount, including: When the monitored material amount in the mother liquor tank exceeds the upper limit of the preset mother liquor level range, a first adjusted feed amount of the A tower bottom is obtained according to the material amount in the mother liquor tank and the preset mother liquor level range, and the A tower bottom is adjusted to feed according to the first adjusted feed amount; When the monitored material amount in the mother liquor tank is lower than the lower limit of the preset mother liquor level range, the second adjusted feed amount of the A tower bottom is obtained according to the material amount in the mother liquor tank and the preset mother liquor level range, and the A tower bottom is adjusted to feed according to the second adjusted feed amount.

10. A solvent recovery unit control method, characterized in that: include: In response to a start-up request, the start-up module is used to check the operating parameters of the tower kettle in the solvent recovery unit, and the state of the tower kettle is adjusted according to the check result to initialize the operating parameters and control the operation of the tower kettle; Using a PID control unit, the basic process parameters of the tower kettle during operation are monitored, and the operating state of the tower kettle is adjusted according to the basic process parameters and preset basic process conditions; Using an advanced control and experience control unit, the unstable parameters of the tower kettle during operation are monitored, and the operating state of the tower kettle is adjusted based on the unstable parameters and preset stable conditions, and the preset stable conditions are updated using an experience scheme according to the adjusted unstable parameters of the tower kettle; In response to a parking request, a parking module is used to determine a parking type corresponding to the parking request, and based on the parking type, the tower kettle is controlled to stop operating according to a preset parking plan.

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