A method for preventing the clogging of a discharge line of a crystallizer

Abstract

This invention belongs to the field of crystallizer control, and particularly relates to a method for preventing blockage of the crystallizer discharge pipeline. The method includes: real-time acquisition of liquid level parameters, discharge pipeline pressure parameters, and material accumulation detection parameters at the bottom of the conical mold; generating a discharge control quantity based on the comparison between the liquid level parameters and a preset liquid level control threshold, and adjusting the opening of the discharge valve to stabilize the liquid level; simultaneously comparing the pressure parameters with a preset pressure threshold, and if the pressure exceeds the threshold, intervening to adjust the valve opening until the pressure returns to normal; comparing the accumulation detection parameters with a preset accumulation judgment threshold, and if the accumulation exceeds the threshold, determining operating parameters such as the stirring speed, duration, and start-stop cycle of the small stirring blades based on these parameters, and controlling the operation of the small stirring blades to disperse the accumulated material. This invention effectively prevents blockage of the discharge pipeline and ensures continuous and stable operation of the crystallization process through multi-parameter coordinated control of liquid level, pressure, and accumulation.

Description

Technical Field

[0001] This invention belongs to the field of crystallizer control, and particularly relates to a method for preventing blockage of the crystallizer discharge pipeline. Background Technology

[0002] As a core crystallization equipment in industries such as chemical and metallurgy, the stability of the discharge system of a crystallizer directly determines the continuity of production. Current technologies generally employ a combination of bottom-discharge valves and manual and automatic valves to achieve continuous discharge. These valves must simultaneously perform the dual functions of discharging flow regulation and crystallizer level control, resulting in strict limitations on valve opening and a high risk of crystal blockage at the valve orifice. Although existing technologies attempt to eliminate blockage by designing timed full-opening programs for the valves, this only temporarily alleviates the problem and cannot fundamentally solve it. Furthermore, the conical bottom of the crystallizer is prone to material accumulation, further exacerbating the overall blockage of the discharge pipeline. This double blockage problem leads to poor operational stability and frequent malfunctions in the discharge system, severely hindering the efficient and stable operation of the crystallization process. How to overcome the opening limitations imposed by the dual functions of existing bottom-discharge valves, solve the crystal blockage problem at the valve orifice, simultaneously address the potential for material accumulation at the conical bottom, avoid the combined effects of double blockage, and achieve coordinated control of level stability, pipeline anti-blockage, and bottom clearing to ensure continuous and efficient operation of the crystallization process is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a method for preventing blockage of the discharge pipeline of a crystallizer.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preventing blockage of the discharge pipeline of a crystallizer, wherein an upward-expanding automatic discharge valve is configured at the bottom of the crystallizer, and a set of small stirring blades is provided at the bottom of the crystallizer; the method includes: Real-time acquisition of internal liquid level parameters, discharge pipeline pressure parameters, and material accumulation detection parameters at the bottom of the cone; Preset liquid level control threshold and discharge pipeline pressure threshold; The discharge control quantity is generated based on the comparison result between the liquid level parameter and the preset liquid level control threshold, and the discharge control quantity is transmitted to the actuator of the upward automatic discharge valve to adjust the opening of the upward automatic discharge valve so that the liquid level parameter is stabilized within the preset liquid level control threshold range. At the same time, the collected discharge pipeline pressure parameters are compared with the preset pressure threshold. If the pressure parameters exceed the preset pressure threshold, it is determined that there is a tendency for crystal blockage at the valve. Then, with the goal of returning the pressure parameters to the preset pressure threshold range, the opening of the upward automatic discharge valve is adjusted until the pressure parameters return to the preset pressure threshold range. A preset material accumulation threshold is set. The accumulation detection parameters of the material at the bottom of the crystallizer cone are compared with the preset accumulation threshold. If the detection parameters are greater than the preset accumulation threshold, the operating parameters of the small stirring blade are determined based on the accumulation detection parameters, and a control command is sent to the drive mechanism of the small stirring blade to control the small stirring blade to operate according to the determined operating parameters.

[0005] Specifically, the discharge control quantity is generated based on the comparison result between the liquid level parameter and the preset liquid level control threshold, including: Calculate the liquid level deviation between the current liquid level parameter and the preset liquid level control threshold; Calculate the proportional component based on the liquid level deviation value, and perform time integration on the liquid level deviation value to obtain the integral cumulative amount. Calculate the integral component based on the integral cumulative amount. Set an integral limit value, compare the accumulated integral amount with the integral limit value, and if the absolute value of the accumulated integral amount is greater than the integral limit value, then perform an anti-integral saturation operation. When the sign of the liquid level deviation value is opposite to the sign of the integral accumulation, the integral lock is released, and time integration of the liquid level deviation value is resumed. The proportional component and the integral component are superimposed to obtain the discharge control quantity.

[0006] Specifically, anti-integral saturation operations include: The accumulated points are compared with the integration limit. If the absolute value of the accumulated points is greater than the integration limit, integration locking is performed. When performing integral locking, the cumulative integral amount is assigned to the integral limit value and given the same sign as the integral limit value. At the same time, the time integration of the liquid level deviation value is stopped, an integral locking flag is generated, and the current liquid level deviation value is recorded as the locking time deviation. During the integral locking period, the current liquid level deviation value is collected in real time at a preset sampling period, and the sign of the current liquid level deviation value is compared with the sign of the deviation at the locking time.

[0007] Specifically, anti-integral saturation operations also include: Set an integral recovery condition, wherein the integral recovery condition is: the sign of the current liquid level deviation value is opposite to the sign of the deviation at the locking time, and the absolute value of the current liquid level deviation value is greater than the preset deviation dead zone value. When the integral recovery condition is met, the integral lock flag is cleared, the integral lock is released, the time integration of the liquid level deviation value is resumed, and the cumulative integral at the moment of unlocking is used as the initial value for integration over a future preset time length. If the points lock period exceeds the preset maximum lock time, the points lock will be forcibly released, and the accumulated points will be cleared to zero before the points are restored.

[0008] Specifically, calculating the proportional component based on the liquid level deviation value includes: A preset liquid level control threshold is provided, which includes an upper liquid level threshold and a lower liquid level threshold. The liquid level range between the upper liquid level threshold and the lower liquid level threshold is divided into multiple continuous liquid level intervals, and each liquid level interval corresponds to a preset proportional coefficient. Obtain the current liquid level parameter and compare it with the upper limit threshold and the lower limit threshold. If the current liquid level parameter is greater than the upper limit threshold or less than the lower limit threshold, then directly execute the maximum opening adjustment or the minimum opening adjustment. If the current liquid level parameter is between the upper and lower limits of the liquid level threshold, then the liquid level range to which the current liquid level parameter belongs is determined, and the proportional coefficient corresponding to the liquid level range is read. Calculate the liquid level deviation between the current liquid level parameter and the preset liquid level control threshold, wherein the preset liquid level control threshold is the average of the upper liquid level threshold and the lower liquid level threshold; Multiplying the liquid level deviation value by the proportional coefficient yields the proportional control component.

[0009] Specifically, determining the liquid level range to which the current liquid level parameter belongs includes: A hysteresis interval is set between two adjacent liquid level intervals. The width of the hysteresis interval is a preset boundary width value, and the center of the hysteresis interval coincides with the boundary line of the adjacent liquid level interval. The direction of change of the current liquid level parameter is obtained, and the direction of change includes a first direction of change from a low range to a high range and a second direction of change from a high range to a low range; If the current liquid level parameter changes in the first direction, the boundary switching point is set to the sum of the upper limit threshold of the adjacent liquid level interval and half the width of the hysteresis interval; if the current liquid level parameter changes in the second direction, the boundary switching point is set to the difference between the upper limit threshold of the adjacent liquid level interval and half the width of the hysteresis interval. The current liquid level parameter is compared with the boundary switching point. If the current liquid level parameter is greater than or equal to the boundary switching point, the current liquid level parameter is determined to belong to the high range; if the current liquid level parameter is less than the boundary switching point, the current liquid level parameter is determined to belong to the low range.

[0010] Specifically, the collected pressure parameters of the discharge pipeline are compared with preset pressure thresholds, including: A preset pressure threshold P_set and a dead zone value ΔP are defined, wherein the dead zone value ΔP is a constant greater than 0; Construct an anti-blocking dead zone interval according to the preset pressure threshold P_set and the dead zone value ΔP. The lower limit value of the anti-blocking dead zone interval is P_set, and the upper limit value is P_set + ΔP; Collect the pressure parameter P_curr of the discharge pipeline in real time and compare P_curr with the anti-blocking dead zone interval; If P_curr ≤ P_set, it is determined that the current discharge pipeline is in a normal flow state, and the current opening degree of the up-opening type automatic discharging valve is maintained; If P_set < P_curr ≤ P_set + ΔP, it is determined that the current pressure of the discharge pipeline is within the dead zone range, and the current opening degree of the up-opening type automatic discharging valve is maintained unchanged without intervening in the anti-blocking adjustment. At the same time, the step of generating the discharge control quantity based on the liquid level parameter is continued to be executed; If P_curr > P_set + ΔP, it is determined that there is a tendency of crystal blockage in the current discharge pipeline, intervene in adjusting the opening degree of the up-opening type automatic discharging valve, suspend the step of generating the discharge control quantity based on the liquid level parameter, and generate an anti-blocking opening increment according to the deviation degree between P_curr and P_set + ΔP, and execute after superimposing the anti-blocking opening increment on the current opening value.

[0011] Specifically, when intervening in adjusting the opening degree of the up-opening type automatic discharging valve, set the pressure anti-blocking control priority to be higher than the liquid level control priority, including: Set a pressure anti-blocking status flag bit. The pressure anti-blocking status flag bit includes an effective state and an invalid state, and the initial state is the invalid state; Before the step of generating the discharge control quantity based on the liquid level parameter is executed, read the pressure anti-blocking status flag bit; If the pressure anti-blocking status flag bit is in the invalid state, continue to execute the step of generating the discharge control quantity based on the liquid level parameter, and transmit the generated discharge control quantity to the actuator of the up-opening type automatic discharging valve; If the pressure anti-blocking status flag bit is in the effective state, suspend the execution of the step of generating the discharge control quantity based on the liquid level parameter, keep the current opening degree of the up-opening type automatic discharging valve unchanged, and wait until the pressure anti-blocking status flag bit returns to the invalid state before resuming the liquid level control.

[0012] Specifically, when intervening in adjusting the opening degree of the up-opening type automatic discharging valve, setting the pressure anti-blocking control priority to be higher than the liquid level control priority further includes: When comparing the collected pressure parameter of the discharge pipeline with the preset pressure threshold, if the pressure parameter exceeds the preset pressure threshold, it is determined that there is a tendency of crystal blockage at the valve, set the pressure anti-blocking status flag bit to the effective state, and intervene in adjusting the opening degree of the up-opening type automatic discharging valve; After adjusting the opening of the automatic discharge valve, the pressure parameters of the discharge pipeline are collected in real time and continuously compared with the preset pressure threshold. When the pressure parameter returns to the preset pressure threshold range, it is determined that the crystal blockage trend has been eliminated, the pressure anti-blockage status flag is set to an invalid state, and the step of generating the discharge control amount based on the liquid level parameter is resumed. When the liquid level control is restored, the discharge control quantity is regenerated based on the comparison result between the current liquid level parameters inside the crystallizer and the preset liquid level control threshold. The discharge control quantity is then transmitted to the actuator of the upward-expanding automatic discharge valve to adjust the valve opening to the state required for liquid level control.

[0013] Specifically, when the small stirring blades operate according to defined operating parameters, this includes: Set a small stirring blade running status flag bit, which includes running status and stop status, with the initial status being stop status; In the preset accumulation judgment threshold comparison step, if the detection parameter is greater than the preset accumulation judgment threshold, it is determined that there is crystalline material accumulation at the bottom of the cone. Before sending the control command to the drive mechanism of the small stirring blade, the running status flag of the small stirring blade is set to the running status. A control command is sent to the drive mechanism of the small stirring blade to control the small stirring blade to start running according to the determined operating parameters. The operating parameters include stirring speed, single operation duration and single stop duration. The single operation duration and single stop duration constitute the start-stop cycle. During the operation of the small agitator blades, before the controller performs the step of comparing the discharge pipeline pressure parameters with the preset pressure threshold, it first reads the small agitator blades' operating status flag bit. If the small agitator blade's operating status flag is in the operating state, the pressure anti-blockage opening adjustment action will be paused, and the current opening of the upward-expanding automatic discharge valve will remain unchanged. The controller will continuously collect the discharge pipeline pressure parameters and perform threshold comparison and judgment normally, cache and record abnormal events of pressure exceeding the threshold, and continuously monitor the small agitator blade's operating status flag.

[0014] Specifically, when the small stirring blades operate according to the determined operating parameters, it also includes: If the small agitator blade's running status flag is in the stopped state, the normal procedure will be performed to compare the discharge pipeline pressure parameters with the preset pressure threshold and intervene to adjust the opening of the upper-mounted automatic discharge valve. During the operation of the small stirring blade, the cumulative operating time of the small stirring blade is continuously monitored according to the single operation time and single stop time in the determined operating parameters. When the cumulative operating time reaches the single operation time, the small stirring blade is controlled to stop operating and the running status flag of the small stirring blade is set to the stop state. After the single stop time ends, the running status flag of the small stirring blade is set to the running state again and the small stirring blade is restarted. When the pressure anti-blocking step is paused during the operation of the small stirring blade, the controller continues to collect the pressure parameters of the discharge pipeline in real time, but does not perform threshold comparison or opening adjustment. The collected pressure parameters are compared with the preset pressure threshold. If the pressure parameters exceed the preset pressure threshold, the over-threshold event and the corresponding pressure parameter value are recorded, and an anti-blocking demand cache record is generated. When the small agitator blade running status flag is switched to the stop state, during the pressure anti-blocking step, the anti-blocking demand cache record is read first. If there is an unprocessed over-threshold event in the anti-blocking demand cache record, the step of intervening to adjust the opening of the upper automatic discharge valve is immediately executed according to the pressure parameters in the cache record.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention collects three core parameters in real time: the liquid level inside the crystallizer, the pressure of the discharge pipeline, and the material accumulation at the bottom of the cone. Corresponding control thresholds are preset and coordinated. Specifically, by comparing the liquid level parameter with the preset threshold to generate the discharge control quantity, the opening of the upward-expanding automatic discharge valve is adjusted, stabilizing the liquid level in the crystallizer and preventing crystallization blockage caused by liquid level fluctuations. Simultaneously, by comparing the pressure parameter with the preset threshold, the valve opening is promptly adjusted when a tendency for crystal blockage appears at the valve, enabling prediction and rapid removal of blockage trends, thus addressing the pain point of easy valve blockage in existing systems. By comparing the accumulation detection parameter with the preset threshold, the operating parameters of the small stirring blade are dynamically determined based on the degree of accumulation, and its operation is controlled. This clears the material accumulation at the bottom of the cone, preventing further blockage of the discharge pipeline. The synergistic effect of these three mechanisms forms a closed-loop control system from three dimensions: liquid level stability, valve port anti-blockage, and bottom clearing of accumulation. This solves the dual problems of valve port blockage and bottom accumulation in existing technologies, improving the operational stability of the discharge system, reducing equipment failure rates, and ensuring continuous, efficient, and stable operation of the crystallization process. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the calcium nitrate crystallizer of the present invention; Figure 2 This is a structural diagram of the top-mounted automatic discharge valve of the present invention; Figure 3 This is a flowchart of a method for preventing blockage of the discharge pipeline of a crystallizer according to the present invention.

[0017] Attachment markings: 1. Motor; 2. Reducer; 3. First coupling; 4. Frame; 5. Mounting base plate; 6. Packing seal assembly; 7. Drive shaft; 8. Second coupling; 9. Agitator shaft; 10. First agitator; 11. Second agitator; 12. Bottom bearing; 13. Agitator; 14. Frequency converter. Detailed Implementation

[0018] Example 1 Please see Figures 1-2 This invention provides a crystallizer, comprising: a motor 1, a reducer 2, a first coupling 3, a frame 4, a mounting base plate 5, a packing seal assembly 6, a drive shaft 7, a second coupling 8, a stirring shaft 9, a first stirrer 10, a second stirrer 11, a bottom bearing 12, a stirrer 13, and a frequency converter 14. A discharge pipeline is provided at the conical bottom of the crystallizer, and an upward-expanding automatic discharge valve is configured at the lower part of the crystallizer. The upward-expanding automatic discharge valve is used to adjust the discharge flow rate and control the liquid level inside the crystallizer. A set of small stirring blades, each composed of a stirrer 13, is provided at the bottom of the crystallizer. The stirrer 13 is installed at the lower end of the stirring shaft 9 and extends to the conical bottom of the crystallizer. The small stirring blades are used to break up the accumulation of crystallized material at the conical bottom of the crystallizer. Please refer to [link to relevant documentation]. Figure 3 This embodiment provides a method for preventing blockage of the crystallizer's discharge pipeline, comprising: S1. Real-time acquisition of liquid level parameters inside the crystallizer via a liquid level sensor installed inside the crystallizer; real-time acquisition of pressure parameters of the discharge pipeline via a pressure sensor installed on the discharge pipeline; real-time acquisition of material accumulation detection parameters at the bottom of the cone via a material accumulation detection sensor installed at the bottom of the crystallizer cone. S2. A preset liquid level control threshold and a discharge pipeline pressure threshold are set. A discharge control quantity is generated based on the comparison result between the liquid level parameter and the preset liquid level control threshold. The discharge control quantity is transmitted to the actuator of the upward-expanding automatic discharge valve to adjust the opening of the upward-expanding automatic discharge valve so that the liquid level parameter is stabilized within the preset liquid level control threshold range. S3. Simultaneously, the collected discharge pipeline pressure parameters are compared with the preset pressure threshold. If the pressure parameters exceed the preset pressure threshold, it is determined that there is a tendency for crystal blockage at the valve. The opening of the upward-expanding automatic discharge valve is adjusted until the pressure parameters return to the preset pressure threshold range. S4. A preset material accumulation judgment threshold is set. The accumulation detection parameters of the material at the bottom of the crystallizer cone are compared with the preset accumulation judgment threshold. If the detection parameter is greater than the preset accumulation judgment threshold, it is determined that there is crystalline material accumulation at the bottom of the cone. Based on the specific value of the accumulation detection parameter, the operating parameters of the small stirring blade are determined. The start-stop cycle includes the single operation time and the single stop time. The single operation time is positively correlated with the smooth accumulation detection value and increases as the smooth accumulation detection value increases. The single stop time is negatively correlated with the smooth accumulation detection value and decreases as the smooth accumulation detection value increases. This allows the small stirring blade to extend the stirring operation time and shorten the intermittent stop time when the material accumulation is severe, and shorten the stirring operation time and extend the intermittent stop time when the material accumulation is slight. The overall stirring intensity is positively correlated with the accumulation detection parameters.

[0019] S5. Send a control command to the drive mechanism of the small stirring blade to control the small stirring blade to operate according to the determined operating parameters, apply a stirring force to the material at the bottom of the cone to disperse the accumulated material and prevent the discharge pipeline from being blocked.

[0020] It should be further explained that in this embodiment, the discharge control quantity is generated based on the comparison result between the liquid level parameter and the preset liquid level control threshold, including: S201. Calculate the liquid level deviation between the current liquid level parameter and the preset liquid level control threshold. S202. Calculate the proportional component based on the liquid level deviation value, and perform time integration on the liquid level deviation value to obtain the integral cumulative amount. Calculate the integral component based on the integral cumulative amount, specifically including: within each discrete control cycle of fixed duration, obtain the liquid level deviation value of the current cycle; based on the integral cumulative amount at the end of the previous cycle, superimpose the product of the current liquid level deviation value and the cycle duration to calculate the original integral cumulative amount; compare the absolute value of the original integral cumulative amount with the amplitude of a pre-tuned integral limit value adapted to the liquid level control characteristics of the automatic discharge valve on this crystallizer; if the absolute value of the original integral cumulative amount does not exceed the integral limit value, keep the original integral cumulative amount unchanged and set the integral lock flag to invalid; if the absolute value of the original integral cumulative amount exceeds the integral limit value, determine that integral saturation has been triggered, immediately execute the integral lock operation, forcibly assign the integral cumulative amount to the integral limit value with the same sign as the original integral cumulative amount, and set the integral lock flag to valid; regardless of whether integral lock is triggered, this... Each cycle is based on a multiplication operation between the currently determined integral accumulation and a pre-tuned integral coefficient. The product is the integral component of the current cycle, which is directly superimposed with the proportional component to generate the discharge control quantity. When the integral lock flag is valid, the above integral accumulation operation is prohibited. Instead, the currently stored integral accumulation is multiplied by a preset decay coefficient greater than 0 and less than 1 at preset decay intervals to obtain the updated integral accumulation. The integral component of the corresponding cycle is calculated synchronously based on the updated integral accumulation to achieve a smooth return of the valve opening during the integral lock period. During the integral lock period, if the liquid level deviation is detected to be reversed and its absolute value is greater than the preset deviation dead zone value, the integral lock flag is cleared to release the lock, and the normal integral accumulation process is restored with the current decayed integral accumulation as the initial value. If the duration of the integral lock state exceeds the preset maximum lock time threshold, the integral lock flag is forcibly cleared, and the integral accumulation is forcibly reset to zero, restoring the normal integral accumulation process with zero as the initial value. This embodiment directly outputs the integral component when the limit is not exceeded, and clamps the output before outputting and synchronously starts attenuation update when the limit is exceeded. This achieves adaptive management of the integral link and avoids valve opening overshoot and liquid level oscillation caused by integral saturation from the root.

[0021] S203. Set an integral limit value, compare the cumulative integral amount with the integral limit value, and if the absolute value of the cumulative integral amount is greater than the integral limit value, perform an anti-integral saturation operation. S204. When the sign of the liquid level deviation value is opposite to the sign of the integral accumulation, the integral lock is released, and the time integration of the liquid level deviation value is resumed. S205. The proportional component and the integral component are superimposed to obtain the discharge control quantity.

[0022] It should be further explained that the anti-integral saturation operation in this embodiment includes: S2031. Compare the accumulated points with the integration limit value. If the absolute value of the accumulated points is greater than the integration limit value, then perform points locking. S2032. When performing integral locking, the cumulative integral amount is assigned to the integral limit value and given the same sign as the integral limit value. At the same time, the time integration of the liquid level deviation value is stopped, an integral locking flag is generated, and the current liquid level deviation value is recorded as the locking time deviation. S2033. During the integral locking period, the current liquid level deviation value is collected in real time with a preset sampling period, and the sign of the current liquid level deviation value is compared with the sign of the deviation at the locking time. S2034. Set integral recovery conditions, wherein the integral recovery conditions are: the sign of the current liquid level deviation value is opposite to the sign of the deviation at the locking time, and the absolute value of the current liquid level deviation value is greater than the preset deviation dead zone value. When the integral recovery condition is met, the integral lock flag is cleared, the integral lock is released, the time integration of the liquid level deviation value is resumed, and the cumulative integral at the moment of unlocking is used as the initial value for integration over a future preset time length. S2035. During the points lock period, if the points lock duration exceeds the preset maximum lock time, the points lock will be forcibly released, and the accumulated points will be cleared to zero before the points are restored.

[0023] It should be further noted that the anti-integral saturation operation in this embodiment also includes: S2036. Set the integral attenuation coefficient, wherein the integral attenuation coefficient is a constant greater than 0 and less than 1; S2037. During the integration lock period, with a preset decay period as the time interval, at the end of each decay period, the current cumulative integration amount is multiplied by the integration decay coefficient to obtain the updated cumulative integration amount, and the updated cumulative integration amount replaces the original cumulative integration amount. S2038. Repeat the above multiplication operation so that the cumulative integral decreases periodically in the form of a geometric sequence. S2039. Set an early release threshold, wherein the early release threshold is the product of the integral limit value and a preset first proportional coefficient, wherein the preset first proportional coefficient is a constant greater than 0 and less than 1; after each decay cycle, compare the absolute value of the updated integral accumulation with the early release threshold; if the absolute value of the updated integral accumulation is less than the early release threshold, then release the integral lock early and resume time integration of the liquid level deviation value.

[0024] Next, a specific complete example will be used to illustrate the entire process. The example is only to illustrate the feasibility of the calculation and does not represent the actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, in this embodiment, the following are preset: the target value for the crystallizer liquid level control (preset liquid level control threshold) is 1500mm; the liquid level deviation value is uniformly defined as = current actual liquid level parameter - preset liquid level control threshold; the preset positive maximum limit value for the integral accumulation is +100, and the preset negative maximum limit value is -100 (i.e., the integral limit value is ±100); the preset deviation dead zone value for integral recovery is 5mm; the preset integral attenuation coefficient is 0.8, and the attenuation execution cycle is 5 seconds; the preset integral early release threshold is the absolute value of the integral limit value multiplied by the preset first proportional coefficient 0.5, that is, the corresponding positive early release threshold is +50, and the negative early release threshold is -50; the preset maximum integral lock time is 30 seconds. When the real-time liquid level parameter in the crystallizer is 1550mm, the calculated liquid level deviation is +50mm. Because the liquid level remains above the control target value and the positive deviation persists, the integral accumulation continues to increase over time to +105. This value exceeds the positive integral limit of +100, immediately triggering an anti-integral saturation operation and executing integral locking. During locking, the integral accumulation is forcibly clamped to the positive limit of +100, and the integral accumulation of subsequent liquid level deviation values ​​is simultaneously stopped. An integral locking flag is generated, and the liquid level deviation at the time of locking is recorded as +50mm. During the locking period, a decay calculation is performed every 5 seconds, updating the current integral accumulation by multiplying it by an integral decay coefficient of 0.8. The integral accumulation decays sequentially from +100 to +80, +64, +51.2, and +40.96. When it decays to +4... When the value is 0.96, it is less than the positive early release threshold +50, so the integral lock is immediately released early and normal integral accumulation calculation is resumed. If, during the decay process, the liquid level deviation value gradually decreases from +50mm at the time of lock to -8mm, the sign of the current liquid level deviation value is opposite to the sign of the deviation at the time of lock, and the absolute value of 8mm is greater than the preset deviation dead zone value of 5mm, the integral recovery condition is also met. After the lock is released, the real-time integral accumulation at the time of release is used as the initial value for subsequent integral accumulation. If the duration of integral lock reaches the preset maximum lock time of 30 seconds and none of the above integral recovery conditions are met, the integral lock is forcibly released, the integral accumulation is cleared to zero, and normal integral calculation is resumed. This ensures that the integral link is always under control and avoids valve opening overshoot and liquid level oscillation caused by integral saturation from the root.

[0025] This invention sets an integral limit value. When the accumulated integral exceeds the limit, integral locking is performed, clamping the accumulated integral at the limit and stopping the integral accumulation. This fundamentally avoids integral saturation caused by the infinite accumulation of integral terms due to prolonged deviations, effectively eliminating the risks of valve opening overshoot and liquid level oscillation caused by integral saturation. By introducing an integral recovery condition based on opposite signs and adding a deviation dead zone value as a recovery threshold, it ensures that the lock is only released when the deviation direction is truly reversed and the deviation amplitude is sufficient to drive the control response. This prevents frequent integral recovery and locking caused by small fluctuations or noise signals. This invention significantly improves the anti-interference capability and stability of the control system. By introducing an exponential decay mechanism during integral lock-up, the cumulative integral value returns to zero periodically in the form of a geometric sequence. This not only accelerates the exit process from integral saturation but also, by setting an early release threshold, actively recovers the integral value when it decays to a safe range, achieving a smooth transition after integral saturation and avoiding the control abrupt change caused by the integral value jumping directly from the limit value to zero. Furthermore, by setting a maximum lock-up time forced reset mechanism, the invention prevents long-term integral lock-up and loss of regulation capability under abnormal operating conditions, ensuring the robustness and safety of the system. In summary, the anti-integral saturation operation of this invention organically integrates integral lock-up, sign criterion, decay regression, dead-zone filtering, and timeout reset, realizing adaptive management of the integral link in level control. This significantly improves the dynamic response performance, steady-state accuracy, and system robustness of the crystallizer level control, providing a stable and reliable foundation for subsequent anti-blockage control of the discharge pipeline.

[0026] It should be further explained that the proportional component calculated based on the liquid level deviation value in this embodiment includes: S2021. A preset liquid level control threshold, wherein the liquid level control threshold includes an upper liquid level threshold and a lower liquid level threshold, and the liquid level range between the upper liquid level threshold and the lower liquid level threshold is divided into multiple continuous liquid level intervals, each liquid level interval corresponding to a preset proportional coefficient. S2022. Obtain the current liquid level parameter, compare the current liquid level parameter with the upper limit threshold and the lower limit threshold. If the current liquid level parameter is greater than the upper limit threshold or less than the lower limit threshold, directly execute the maximum opening adjustment or the minimum opening adjustment. S2023. If the current liquid level parameter is between the upper limit threshold and the lower limit threshold, then determine the liquid level range to which the current liquid level parameter belongs, and read the proportional coefficient corresponding to the liquid level range. S2024. Calculate the liquid level deviation value between the current liquid level parameter and the preset liquid level control threshold, wherein the preset liquid level control threshold is the average value of the upper liquid level threshold and the lower liquid level threshold; S2025. Multiply the liquid level deviation value by the proportional coefficient to obtain the proportional control component.

[0027] It should be further explained that, in this embodiment, determining the liquid level range to which the current liquid level parameter belongs includes: S2023a. A hysteresis interval is set between two adjacent liquid level intervals. The width of the hysteresis interval is a preset boundary width value, and the center of the hysteresis interval coincides with the boundary line of the adjacent liquid level interval. S2023b: Obtain the direction of change of the current liquid level parameter, wherein the direction of change includes a first direction of change from the low range to the high range and a second direction of change from the high range to the low range; S2023c: For any two adjacent continuous liquid level intervals, a boundary reference value between the two adjacent continuous liquid level intervals is predefined. This boundary reference value is the upper limit threshold of the low liquid level interval and the lower limit threshold of the high liquid level interval. A hysteresis interval is set at the boundary reference value between two adjacent liquid level intervals. The width of the hysteresis interval is a preset boundary width value. The hysteresis interval is symmetrically distributed around the boundary reference value. If the current liquid level parameter changes in the first direction, the boundary switching point is set to the sum of the interval boundary reference value and half the width of the hysteresis interval; if the current liquid level parameter changes in the second direction, the boundary switching point is set to the difference between the interval boundary reference value and half the width of the hysteresis interval. S2023d. Compare the current liquid level parameter with the boundary switching point. If the current liquid level parameter is greater than or equal to the boundary switching point, it is determined that the current liquid level parameter belongs to the high range; if the current liquid level parameter is less than the boundary switching point, it is determined that the current liquid level parameter belongs to the low range. This embodiment determines the liquid level range based on the direction of change of the current liquid level parameter using the corresponding boundary switching point, so that the liquid level parameter maintains its original range affiliation when it changes within the hysteresis range, avoiding frequent switching of the proportional coefficient at the range boundary.

[0028] Next, a specific complete example will be used to illustrate the entire process. This example is only to illustrate the feasibility of the calculation and does not represent the actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, in this embodiment, the upper limit threshold H_max of the liquid level is set to 1800mm and the lower limit threshold H_min is set to 1200mm. The liquid level range between H_min and H_max is divided into three continuous control intervals. The proportional coefficients K1, K2, and K3 corresponding to each interval are tuned based on four dimensions: the variable cross-section structural characteristics of the conical vessel of the crystallizer, the safety priority of liquid level control, the equal percentage flow characteristics of the upward-expanding automatic discharge valve, and the synergistic requirements of the crystallization process of this invention for the steady-state accuracy of liquid level and the prevention of material blockage. The tuning principle is "small coefficient in the low liquid level range to suppress overshoot and prevent material blockage, moderate coefficient in the target range to balance accuracy and stability, and large coefficient in the high liquid level range for fast response to prevent overflow and material accumulation". At the same time, it matches the valve action life and the continuous crystallization production requirements. The specific interval division and coefficient settings include: The first range is the low liquid level range of 1200mm to 1400mm, corresponding to a proportional coefficient K1=0.5. This range is located at the bottom of the crystallizer cone, and the cross-sectional area of ​​the vessel shrinks rapidly as the liquid level decreases. The liquid level fluctuation caused by the same valve opening change is much greater than that in the medium and high liquid level range. If an excessively large proportional coefficient is used, it is easy to cause excessive valve closure, sudden drop in liquid level, or even interruption of discharge. At the same time, closing the valve too quickly will exacerbate the risk of crystal accumulation and blockage at the valve flow channel. Therefore, a smaller proportional coefficient is set to achieve smooth valve closure adjustment, taking into account both the stability of liquid level recovery and the core requirement of preventing discharge blockage. The second range is the target control range of 1400mm to 1600mm, corresponding to a proportional coefficient K2=1.0: This range is centered on the preset liquid level control threshold H_set (the average of H_min and H_max, 1500mm), and is the steady-state working range for the normal operation of the crystallization process. Setting it to 1.0 as the benchmark proportional coefficient can quickly eliminate small liquid level deviations and ensure that the liquid level is stable within the process requirements, while avoiding frequent valve wear caused by excessive adjustment, thus meeting the stable operation requirements of continuous crystallization production. The third range is the high liquid level range of 1600mm to 1800mm, corresponding to a proportional coefficient K3=1.5. The liquid level in this range far exceeds the target control value, posing multiple process risks such as overflow from the vessel, oversaturation and crystallization of the upper material, and increased material accumulation at the bottom of the cone. It is necessary to quickly increase the valve opening and accelerate the discharge to bring the liquid level back down. At the same time, this range is located in the straight section of the crystallizer, where the cross-sectional area of ​​the vessel is constant. The rate of liquid level change caused by the same change in opening is slow and it is not easy to cause overshoot. Therefore, a larger proportional coefficient is set to enhance the adjustment range and achieve a rapid drop in liquid level, eliminating the risk of blockage in the discharge pipeline caused by overflow and material accumulation from the source.

[0029] Based on the aforementioned interval and coefficient settings, the calculation process for the proportional control component under each operating condition includes: Operating Condition 1: Liquid level parameter is 1550mm The current liquid level parameter is 1550mm, which is within the second interval. The proportional coefficient K2 corresponding to this interval is read as 1.0. The liquid level deviation value ΔH is calculated as 1550-1500=50mm, and the proportional control component P=ΔH×K2=50×1.0=50.

[0030] Operating Condition 2: Liquid level parameter is 1650mm The current liquid level parameter is 1650mm, which is within the third interval. The proportional coefficient K3 is read as 1.5. The liquid level deviation value ΔH is calculated as 1650-1500=150mm. The proportional control component P=150×1.5=225. A larger proportional coefficient makes the valve opening increase faster, accelerates the liquid level drop, and quickly eliminates the process risks and blockage hazards caused by high liquid levels.

[0031] Operating Condition 3: Liquid level parameter is 1350mm The current liquid level parameter is 1350mm, which is within the first interval. The proportional coefficient K1 is read as 0.5. The liquid level deviation value ΔH is calculated as 1350-1500=-150mm. The proportional control component P=-150×0.5=-75. The smaller proportional coefficient makes the valve opening decrease more smoothly, avoiding the risk of material interruption and valve flow channel blockage caused by excessive valve closure when the liquid level is too low.

[0032] The setting of hysteresis intervals and the determination of interval affiliation, taking the boundary between the second and third intervals as an example, are as follows: A hysteresis interval is set at the boundary between the second interval and the third interval. The center of the hysteresis interval coincides with the boundary line, and the boundary line corresponds to a liquid level value of 1600 mm. The preset boundary width value W is 20 mm, so the hysteresis interval is from 1590 mm to 1610 mm. In this embodiment, the preset boundary width value W is 20 mm. The core basis for setting this value is the measurement accuracy of the liquid level detection sensor supporting this crystallizer, the maximum amplitude of the normal fluctuation of the liquid level under the on-site working conditions, the width of the single-segment 200-mm liquid level control interval divided in this embodiment, the rated action frequency and service life requirements of the actuating mechanism of the up-spreading type automatic discharging valve, and the steady-state accuracy requirements for liquid level control in the crystallization production process, these four core dimensions. At the same time, it is adapted and set in combination with the preset 5-mm liquid level deviation dead zone value in this embodiment. This width value is much smaller than the width of the single-segment liquid level control interval and will not damage the interval division logic and adjustment characteristics of the segmented proportional control. It is also larger than the normal fluctuation amplitude of the liquid level and the preset deviation dead zone value, which can effectively prevent the proportional coefficient from being frequently switched due to small fluctuations or measurement noise at the interval boundary, thereby preventing the wear and life attenuation caused by the frequent reciprocating action of the actuating mechanism of the up-spreading type automatic discharging valve. At the same time, it will not reduce the response speed and steady-state accuracy of the liquid level control due to too large hysteresis width, and it adapts to the coordinated operation requirements of the anti-blocking control of the discharge pipeline of the crystallizer and the stable adjustment of the liquid level in this invention.

[0033] According to S2023b, obtain the change direction of the current liquid level parameter. If the change direction of the current liquid level parameter is the first direction from the low interval to the high interval (i.e., the liquid level rises), according to S2023c, the boundary switching point is set to the sum of 1600 mm and W / 2, that is, 1600 + 10 = 1610 mm; if the change direction of the current liquid level parameter is the second direction from the high interval to the low interval (i.e., the liquid level drops), the boundary switching point is set to the difference between 1600 mm and W / 2, that is, 1600 - 10 = 1590 mm.

[0034] According to S2023d, compare the current liquid level parameter with the boundary switching point: when the liquid level rises, the current liquid level parameter ≥ 1610 mm is determined to belong to the third interval (high interval), otherwise it still belongs to the second interval (low interval); when the liquid level drops, the current liquid level parameter < 1590 mm is determined to belong to the second interval (low interval), otherwise it still belongs to the third interval (high interval).

[0035] According to S2023e, when the liquid level parameter varies within the hysteresis range of 1590 mm to 1610 mm, due to different change directions corresponding to different boundary switching points, the liquid level parameter maintains its original interval attribution during fluctuations within this range: that is, when the liquid level rises from the second interval into the hysteresis interval, it still maintains the proportionality coefficient K2 = 1.0 of the second interval; when the liquid level drops from the third interval into the hysteresis interval, it still maintains the proportionality coefficient K3 = 1.5 of the third interval. This avoids frequent switching of the proportionality coefficient between K2 and K3 when the liquid level fluctuates near 1600 mm, ensuring the smoothness of the valve opening adjustment.

[0036] It should be further noted that in this embodiment, the pressure parameter of the discharge pipeline collected is compared with a preset pressure threshold, which specifically includes: S301, a preset pressure threshold P_set and a dead zone value ΔP, where the dead zone value ΔP is a constant greater than 0; S302, based on the preset pressure threshold P_set and the dead zone value ΔP, construct an anti-blocking dead zone interval, where the lower limit value of the anti-blocking dead zone interval is P_set and the upper limit value is P_set + ΔP; S303, collect the pressure parameter P_curr of the discharge pipeline in real time and compare P_curr with the anti-blocking dead zone interval; S304, if P_curr ≤ P_set, it is determined that the current discharge pipeline is in a normal flow state, maintain the current opening of the up-spreading type automatic discharging valve, and continue to execute the step of generating a discharging control amount based on the liquid level parameter; S305, if P_set < P_curr ≤ P_set + ΔP, it is determined that the current pressure of the discharge pipeline is within the dead zone range, maintain the current opening of the up-spreading type automatic discharging valve unchanged, do not intervene in the anti-blocking adjustment, and at the same time continue to execute the step of generating a discharging control amount based on the liquid level parameter; S306, if P_curr > P_set + ΔP, it is determined that there is a tendency of crystal blockage in the current discharge pipeline, intervene in adjusting the opening of the up-spreading type automatic discharging valve, pause the step of generating a discharging control amount based on the liquid level parameter, and generate an anti-blocking opening increment according to the deviation degree between P_curr and P_set + ΔP, and execute after adding the anti-blocking opening increment to the current opening value, which specifically includes: S306a, after determining that P_curr > P_set + ΔP, calculate the change rate R_curr of the pressure parameter in real time, where the change rate R_curr is the change amount of the pressure parameter per unit time; S306b. Set a change rate threshold R_th, compare R_curr with R_th. If R_curr > R_th, it is determined that the pressure parameter is showing a rapid upward trend. Determine the emergency opening increment coefficient based on the ratio of R_curr to R_th. The emergency opening increment coefficient is greater than the basic anti-blocking opening increment coefficient. Further, in this embodiment, the basic anti-blocking opening increment coefficient specifically represents the increase in the opening of the upward-expanding automatic discharge valve corresponding to a unit pressure deviation under the normal slow blockage condition where the discharge pipeline pressure exceeds the upper limit of the anti-blocking dead zone, but the pressure rise rate does not exceed the preset change rate threshold. In this embodiment, it is adjusted according to the rule that the valve opening increases by 2% for every 0.01 MPa exceeding the upper limit of the anti-blocking dead zone. The core basis is the pressure characteristics of the normal flow in the crystallizer discharge pipeline, the flow regulation characteristics of the upward-expanding automatic discharge valve, and the blockage development law of the crystallized material. The emergency opening... The incremental coefficient specifically represents the amplification correction coefficient for the basic opening increment under rapid blockage conditions where the pressure in the discharge pipeline exceeds the upper limit of the anti-blockage dead zone and the pressure rise rate exceeds the preset change rate threshold. Its core tuning is based on the ratio of the pressure rise rate to the preset change rate threshold, the working condition characteristics of rapid crystal blockage development, the maximum allowable valve opening and action response speed, and is set to 1.2 to 2.0 times the basic anti-blockage opening increment coefficient (1.5 times in this embodiment), always greater than the basic anti-blockage opening increment coefficient. This achieves smooth valve opening adjustment under normal blockage conditions, avoiding frequent wear of the actuator, while rapidly and significantly increasing the valve opening under emergency blockage conditions with a sudden pressure rise. The rapidly formed crystal blockage is broken by flushing with a large flow of material. At the same time, it is compatible with the preset pressure threshold, dead zone value, and change rate threshold of this embodiment, matching the core requirements of the anti-blockage priority control logic of this invention and the continuous and stable operation of the crystallization process.

[0037] S306c: Determine the final opening increment based on the emergency opening increment coefficient and the current deviation, and then add the final opening increment to the current opening value before execution.

[0038] S307. After intervening to adjust the opening of the automatic discharge valve, continue to collect the discharge pipeline pressure parameter P_curr in real time, and compare P_curr with the preset pressure threshold P_set. S308. If P_curr≤P_set, then the blockage trend is determined to be eliminated, the anti-blockage intervention is stopped, the step of generating the discharge control quantity based on the liquid level parameter is resumed, and the opening of the upward-expanding automatic discharge valve is recalculated and adjusted according to the current liquid level parameter. For example, the specific logic of adjusting the opening of the upward-expanding automatic discharge valve in this embodiment is as follows: taking the liquid level parameter inside the crystallizer collected in real time during the current control cycle as input, firstly calculate the liquid level deviation value between the current liquid level parameter and the preset liquid level control threshold; then, according to the matching rule of the liquid level interval and the corresponding proportional coefficient pre-divided in this embodiment, determine the proportional coefficient corresponding to the liquid level interval to which the current liquid level parameter belongs, and multiply the liquid level deviation value by the proportional coefficient to obtain the proportional component of the current cycle; at the same time, according to the integral operation rule with anti-integral saturation mechanism set in this embodiment, the liquid level deviation value is further processed. The integral component of the current cycle is calculated by accumulating the integral. The proportional component calculated in the same cycle is superimposed with the integral component to generate the discharge control quantity, and the discharge control quantity is converted into the target opening value of the upward-expanding automatic discharge valve. After determining the target opening value, the current opening value of the upward-expanding automatic discharge valve is obtained within the preset buffer time window in this embodiment. The difference between the current opening value and the target opening value is calculated. The difference is decomposed into multiple sub-steps that are no greater than the preset maximum single adjustment step size. The opening adjustment command is executed cycle by cycle in the continuous control cycle until the opening of the upward-expanding automatic discharge valve reaches the target opening value. This achieves a smooth transition of the liquid level parameters inside the crystallizer from the anti-blocking intervention state to the normal liquid level control state, avoiding the risk of liquid level oscillation and secondary crystal blockage caused by sudden changes in the opening of the upward-expanding automatic discharge valve.

[0039] S309. If P_curr>P_set, maintain the anti-blocking intervention state and continue to adjust the opening according to the degree of deviation between P_curr and P_set+ΔP until P_curr returns to below P_set.

[0040] Next, a specific complete example will be used to illustrate the entire process. This example is only to illustrate the feasibility at the computational level and does not represent actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, in this embodiment, before the pressure anti-blocking control of the crystallizer discharge pipeline begins, the following parameters adapted to the discharge characteristics, valve adjustment performance, and anti-blocking control requirements of this crystallizer are preset, and the meaning, applicable scenarios, and correlations of each parameter are clearly defined, thoroughly clarifying the boundaries and differences between the parameters: First, the preset pressure threshold P_set is 0.5 MPa. This threshold is the pressure under normal flow conditions in the discharge pipeline. The maximum allowable pressure parameter is the basic benchmark value for determining whether there is a tendency for crystal blockage in the discharge pipeline; second, the preset dead zone value ΔP is 0.05 MPa, used to construct the anti-blockage dead zone interval to avoid repeated wear of the actuator of the upward-expanding automatic discharge valve caused by frequent small fluctuations in pressure near the basic threshold, thus extending the service life of the equipment; third, based on the above two parameters, the anti-blockage dead zone interval is clearly defined as a pressure range of 0.5 MPa to 0.55 MPa, where the lower limit of the interval is the preset pressure threshold of 0.5 MPa, and the upper limit of the interval is the sum of the preset pressure threshold and the dead zone value; fourth, the preset pressure change rate threshold is 0.01 MPa per second, used... Distinguishing between normal, slow fluctuations in pressure parameters and abnormally rapid increases caused by crystal blockage is the core judgment boundary for classifying conventional anti-blockage conditions and emergency anti-blockage conditions; Fifth, a preset basic anti-blockage opening increment coefficient is defined as the increase in valve opening corresponding to a unit pressure deviation under conventional blockage conditions. In this embodiment, the tuning rule for this coefficient is: for every 0.01 MPa that the actual pressure of the discharge pipeline exceeds the upper limit of the anti-blockage dead zone, the opening of the upward-expanding automatic discharge valve increases by 2%. This coefficient is only applicable to conventional slow blockage conditions where the pressure exceeds the upper limit of the anti-blockage dead zone, but the pressure rise rate does not exceed the preset change rate threshold; Sixth, the preset emergency opening increment coefficient is 1.5 times. This parameter is a dimensionless amplification correction coefficient, used only to amplify the basic anti-blocking opening increment coefficient. It is an intermediate conversion parameter for calculating the execution coefficient under emergency conditions and is specifically used for emergency anti-blocking response scenarios with rapid pressure increases. Its value is always greater than 1 times. Seventh, the emergency opening increment coefficient is clearly defined as the final opening increment calculation coefficient under emergency blockage conditions. It is calculated by the fixed formula "basic anti-blocking opening increment coefficient × emergency opening increment coefficient multiplier". In this embodiment, the corresponding tuning rule is: for every 0.5 times the actual pressure of the discharge pipeline exceeds the upper limit of the anti-blocking dead zone interval.0.01 MPa corresponds to a 3% increase in the opening of the upward-expanding automatic discharge valve. This value is always greater than the basic anti-clogging opening increment coefficient. This coefficient is only applicable to emergency conditions where the pressure exceeds the upper limit of the anti-clogging dead zone and the pressure rise rate exceeds a preset change rate threshold, resulting in rapid crystal blockage. This achieves the dual control objectives of smoothly adjusting the valve opening and reducing the frequency of actuator actions under normal operating conditions, and rapidly and significantly opening the valve under emergency conditions to break up the rapidly formed crystal blockage through a large flow rate of discharge. This aligns with the anti-clogging priority control logic of this invention and the core requirement for continuous and stable operation of the crystallization process.

[0041] Operating Condition 1: Pressure is normal, and the pressure has not entered the anti-blockage dead zone. The real-time collected pressure parameter of the discharge pipeline is 0.48 MPa. The controller compares this pressure parameter with the lower limit of the anti-clogging dead zone, 0.5 MPa, and determines that 0.48 MPa is less than 0.5 MPa, meaning that the current discharge pipeline is in a normal flow state and there is no tendency for crystal blockage. The controller maintains the current opening of the upward-expanding automatic discharge valve unchanged and does not perform any anti-clogging intervention actions. At the same time, the controller continues to execute the step of generating the discharge control quantity based on the liquid level parameter, and adjusts the valve opening in real time according to the liquid level deviation to maintain the stability of the liquid level in the crystallizer.

[0042] Operating Condition 2: Pressure enters the anti-blockage dead zone; no intervention required. The real-time collected pressure parameter of the discharge pipeline is 0.52 MPa. The controller compares this pressure parameter with the anti-clogging dead zone and determines that 0.52 MPa is within the range of 0.5 MPa to 0.55 MPa, i.e., the pressure is within the anti-clogging dead zone. The controller determines that the current pressure increase is a slight fluctuation and has not yet formed a clear trend of crystal blockage, so no anti-clogging intervention is required. The controller maintains the current opening of the upward-expanding automatic discharge valve and does not generate an anti-clogging opening increment to avoid frequent operation of the valve actuator due to small pressure fluctuations. At the same time, the controller continues to execute the step of generating the discharge control quantity based on the liquid level parameter, maintaining normal liquid level regulation function.

[0043] Operating Condition 3: When the pressure exceeds the anti-blocking dead zone, anti-blocking intervention is initiated. The real-time collected pressure parameter of the discharge pipeline is 0.58 MPa. The controller compares this pressure parameter with the upper limit of the anti-clogging dead zone, 0.55 MPa, and determines that 0.58 MPa is greater than 0.55 MPa, meaning the pressure has exceeded the anti-clogging dead zone. The controller determines that the discharge pipeline has a tendency to become clogged by crystals and immediately initiates the anti-clogging intervention process: First, the controller pauses the step of generating the discharge control quantity based on the liquid level parameter to avoid conflict between the liquid level control command and the anti-blocking intervention command. Second, the calculated pressure exceeds the upper limit of the dead zone by 0.03 MPa; Third, based on the preset opening increment coefficient, the opening is increased by 2% for every 0.01 MPa increase. The basic anti-clogging opening increment coefficient is calculated to be 6%, which means the valve opening needs to be increased by 6%. Fourth, add the 6% opening increment to the current opening value of the upward-expanding automatic discharge valve to generate a new opening command.

[0044] The controller sends a new opening command to the actuator of the upward-expanding automatic discharge valve. The actuator drives the valve core to move upward, increasing the valve opening and the discharge flow rate to alleviate the clogging trend. After execution, the pressure parameters begin to gradually decrease.

[0045] Operating condition 4: When the pressure recovers to below the threshold, the anti-blocking intervention is discontinued. During the anti-blockage intervention process, the controller continuously collects the pressure parameters of the discharge pipeline in real time with a sampling period of 0.5 seconds. At a certain moment, the collected pressure parameter is 0.49 MPa. The controller compares this pressure parameter with the preset pressure threshold of 0.5 MPa and determines that 0.49 MPa is less than 0.5 MPa, that is, the blockage trend of the discharge pipeline has been eliminated and the pressure parameter has returned to the normal range.

[0046] The controller executes the anti-blocking exit procedure: First, stop anti-blocking intervention and no longer generate anti-blocking opening increments; Second, restore the step of generating the discharge control quantity based on the liquid level parameter; Third, based on the comparison between the current internal liquid level parameters of the crystallizer and the preset liquid level control threshold, the target opening value of the upward-expanding automatic discharge valve is recalculated, and the valve opening is adjusted to the state required for liquid level control to ensure the stability of the liquid level in the crystallizer. For example, in this embodiment, the specific process of recalculating the target opening value of the upward-expanding automatic discharge valve is as follows: Assuming that after the anti-blocking intervention ends, the current internal liquid level parameter of the crystallizer is 1465mm, the preset liquid level control threshold is 1500mm, and the calculated liquid level deviation value is -35mm, where the negative sign of the liquid level deviation value indicates that the current internal liquid level parameter of the crystallizer is lower than the preset liquid level control threshold; according to the matching rule of the pre-divided liquid level intervals and corresponding proportional coefficients in this embodiment, it is determined that the current liquid level parameter 1465mm belongs to the second interval, and the proportional coefficient K2 corresponding to this liquid level interval is read as 1.0. The liquid level deviation value -35mm is multiplied by the proportional coefficient 1.0 to obtain the proportional component of the current cycle as -35; simultaneously, according to the integral operation rule with anti-integral saturation mechanism set in this embodiment... Then, the liquid level deviation value is integrated and accumulated. Assuming that the integrated accumulation is 20, the integrated accumulation of 20 is multiplied by the pre-tuned integration coefficient 0.1 to obtain the integral component of the current period as 2. The proportional component -35 calculated in the same period is superimposed with the integral component 2 to generate the discharge control quantity -33. The negative sign of the discharge control quantity indicates that the opening adjustment direction of the upward automatic discharge valve is to reduce the opening. According to the mapping relationship between the discharge control quantity and the opening of the upward automatic discharge valve preset in this embodiment, the discharge control quantity -33 is converted into the target opening value of 48% of the upward automatic discharge valve. The target opening value of 48% is lower than the current opening value of 56% maintained during the anti-blocking intervention. By reducing the opening, the discharge flow rate is reduced, driving the liquid level parameter inside the crystallizer to rise back to the preset liquid level control threshold.

[0047] Operating Condition 5: Pressure rises rapidly, triggering emergency anti-blockage response. During the anti-blocking intervention process, in addition to collecting the current pressure parameters, the controller also calculates the rate of change of the pressure parameters. Assuming the pressure parameter at the current sampling time is 0.58 MPa, the pressure parameter at the previous sampling time is 0.56 MPa, and the sampling period is 0.5 seconds, the controller calculates that the pressure rise per unit time is 0.02 MPa, and thus the rate of change of pressure is 0.04 MPa per second.

[0048] The controller compares the calculated pressure change rate of 0.04 MPa per second with the preset change rate threshold of 0.01 MPa per second. It determines that 0.04 MPa per second is greater than 0.01 MPa per second, indicating a rapid increase in the pressure parameter. The controller then determines that the blockage is developing rapidly and needs to initiate an emergency blockage prevention response. First, the calculated pressure exceeds the upper limit of the dead zone by 0.03 MPa; Second, the pressure threshold is preset to 0.5 MPa, the dead zone value is preset to 0.05 MPa, the upper limit of the anti-blocking dead zone is determined by the sum of the pressure threshold and the dead zone value to be 0.55 MPa, the preset basic anti-blocking opening increment coefficient is 2% for every 0.01 MPa that the actual pressure of the discharge pipeline exceeds the upper limit of the anti-blocking dead zone, the preset emergency opening increment coefficient is 1.5 times, and the preset pressure change rate threshold is 0.01 MPa per second. This embodiment calculates the pressure deviation of 0.03 MPa from the real-time collected discharge pipeline pressure parameter of 0.58 MPa. Based on the pre-set basic anti-clogging opening increment coefficient, the conventional anti-clogging basic opening increment is calculated to be 6%. In this embodiment, when the discharge pipeline pressure parameter exceeds the upper limit of the anti-clogging dead zone and the pressure rise rate exceeds a preset change rate threshold, an emergency anti-clogging condition is entered. Based on a pre-set emergency opening increment coefficient multiple, an emergency opening increment coefficient specific to the emergency anti-clogging condition is calculated by multiplying the basic anti-clogging opening increment coefficient by the emergency opening increment coefficient multiple. This is then calculated by multiplying the conventional anti-clogging basic opening increment by the emergency opening increment coefficient. The emergency opening increment coefficient is calculated by multiplying the emergency opening increment coefficients to obtain a 9% emergency opening increment that the valve needs to perform under emergency anti-blocking conditions. The value of this emergency opening increment coefficient is always greater than the basic anti-blocking opening increment coefficient, and the value of this emergency opening increment is always greater than the conventional anti-blocking basic opening increment. To further explain, the conventional anti-blocking basic opening increment in this embodiment refers to the positive opening adjustment range that the upward-expanding automatic discharge valve needs to perform on the basis of the current opening, obtained by multiplying the pre-set basic anti-blocking opening increment coefficient with the real-time calculated pressure deviation value under the conventional blockage condition where the actual pressure of the discharge pipeline exceeds the upper limit of the anti-blocking dead zone and the pressure rise rate does not exceed the preset change rate threshold.

[0049] Third, the 9% emergency opening increment coefficient is added to the current opening value of the upward-expanding automatic discharge valve to generate a new opening command.

[0050] The controller sends a new opening command to the actuator of the upward-expanding automatic discharge valve. The actuator then increases the valve opening by a larger margin, rapidly increasing the discharge flow rate to counteract the rapidly developing blockage trend. After the emergency anti-blockage response is executed, the upward trend of the pressure parameters is suppressed, and they gradually begin to decrease.

[0051] This invention establishes an anti-blocking dead zone, maintaining a constant valve opening when pressure parameters exceed a preset pressure threshold but do not exceed the upper limit of the dead zone. This effectively avoids repeated valve actuation caused by frequent pressure fluctuations near the threshold, significantly extending the service life of the upward-expanding automatic discharge valve actuator. By introducing a pressure change rate judgment mechanism, when pressure parameters exceed the dead zone and the change rate exceeds a preset change rate threshold, it determines that the pressure is rapidly increasing and initiates an emergency anti-blocking response. An emergency opening increment coefficient is determined based on the change rate, rapidly increasing the valve opening with a larger increment. This solves the problem that a single opening adjustment cannot cope with sudden pressure increases, significantly improving the timeliness and effectiveness of the anti-blocking response. By pausing the step of generating the discharge control quantity based on the liquid level parameter, it avoids control command conflicts when anti-blocking intervention and liquid level control share the same valve actuator, ensuring the priority execution of anti-blocking intervention. By recalculating the valve opening after pressure recovery and adjusting it to the state required for liquid level control, a smooth transition between anti-blocking intervention and liquid level control is achieved. The above-mentioned technical means work together to systematically solve the problem of discharge pipeline blockage from three aspects: pressure fluctuation suppression, rapid response, and control coordination, which significantly improves the operational stability and reliability of the crystallizer discharge system.

[0052] It should be further explained that, in this embodiment, when adjusting the opening of the upward-expanding automatic discharge valve, the pressure anti-blockage control priority is set higher than the liquid level control priority, specifically including: S311. Set a pressure anti-blocking status flag bit, which includes an effective state and an invalid state, with the initial state being an invalid state; S312. Before executing the step of generating the discharge control amount based on the liquid level parameter, read the pressure anti-blocking status flag bit; S313. If the pressure anti-blocking status flag is invalid, continue to execute the step of generating the discharge control quantity based on the liquid level parameter, and transmit the generated discharge control quantity to the actuator of the upward-expanding automatic discharge valve. S314. If the pressure anti-blocking status flag is in an effective state, then pause the step of generating the discharge control quantity based on the liquid level parameter, keep the current opening of the upward-expanding automatic discharge valve unchanged, and wait for the pressure anti-blocking status flag to return to an ineffective state before resuming liquid level control. S315. When comparing the collected discharge pipeline pressure parameters with the preset pressure threshold, if the pressure parameters exceed the preset pressure threshold, it is determined that there is a tendency for crystal blockage at the valve. The pressure anti-blockage status flag is immediately set to an effective state, and the opening of the upward-expanding automatic discharge valve is adjusted. Specifically: S315a. While the pressure anti-blocking status flag is set to the effective state and the opening of the upper automatic discharge valve is adjusted, the liquid level parameters inside the crystallizer are continuously collected in real time. S315b: Compare the real-time collected liquid level parameters with the preset liquid level control threshold. If the liquid level parameters exceed the preset liquid level control threshold range and the excess amount reaches the preset liquid level alarm threshold, then generate a liquid level alarm signal. S315c. Based on the liquid level alarm signal, while prioritizing pressure anti-blocking intervention, limit the maximum value of the anti-blocking opening increment to avoid triggering the lower liquid level alarm due to excessively increased opening causing the liquid level to drop too quickly.

[0053] S316. After intervening to adjust the opening of the automatic discharge valve, continue to collect the pressure parameters of the discharge pipeline in real time, and continuously compare the pressure parameters with the preset pressure threshold. S317. When the pressure parameter returns to the preset pressure threshold range, it is determined that the crystal blockage trend has been eliminated, the pressure anti-blockage status flag is set to an invalid state, and the step of generating the discharge control amount based on the liquid level parameter is resumed. S318. When restoring liquid level control, the discharge control quantity is regenerated based on the comparison result between the current internal liquid level parameters of the crystallizer and the preset liquid level control threshold. This discharge control quantity is then transmitted to the actuator of the upward-expanding automatic discharge valve to adjust the valve opening to the state required for liquid level control. Specifically: S318a. When the pressure anti-blocking status flag is set to an invalid state and the liquid level control is restored, a buffer time window is set, the duration of which is a preset buffer time. S318b: Within the buffer time window, limit the adjustment range of the discharge control quantity generated based on the liquid level parameter, and limit the opening change of each adjustment to within the preset maximum step size. S318c After the buffer time window ends, the adjustment range limitation is released, and the normal liquid level control adjustment response is restored.

[0054] Next, a specific complete example will be used to illustrate the entire process. This example is only to illustrate the feasibility of the calculation and does not represent the actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, when the crystallizer starts running and enters a stable working state, the control system completes the initialization of control parameters. The preset pressure threshold is 0.5MPa, the preset liquid level control threshold center value is 1500mm, the corresponding preset liquid level control threshold lower limit is 1432mm, the liquid level control threshold upper limit is 1530mm, the liquid level allowable range is 1432mm to 1530mm, the preset liquid level alarm threshold is the liquid level range 20mm above the liquid level control threshold lower limit, the pressure anti-blocking status flag is initially set to an invalid state, and the initial opening of the upward-expanding automatic discharge valve is 40%. The core of the above liquid level related parameter tuning is based on the variable cross-section structural characteristics of the crystallizer's conical vessel. The crystallization process is defined by four main dimensions: control requirements for crystal slurry supersaturation and residence time, action response characteristics of the top-mounted automatic discharge valve, and core control objectives for preventing blockage in the discharge pipeline. Among these, the lower limit of the liquid level control threshold of 1432mm ensures that the discharge port at the conical bottom of the crystallizer is always submerged in crystal slurry, forming a stable material seal and preventing air from entering the discharge pipeline and causing crystal precipitation and blockage. At the same time, it ensures the effective residence time of the crystal slurry in the reactor to generate large-diameter crystal particles that are not prone to blockage. Moreover, this value is within the pre-defined target liquid level control range of 1400mm to 1600mm, providing sufficient buffer margin for liquid level drop during anti-blockage intervention. The liquid level alarm threshold of 20mm is greater than the pre-set liquid level deviation dead zone value of 5mm, which can avoid false alarms triggered by normal small fluctuations in liquid level. At the same time, it matches the liquid level drop rate and valve action response speed during anti-blockage intervention, providing sufficient liquid level protection action response window. After parameter initialization, the system enters the normal liquid level control mode. In each 0.5-second control cycle, the controller first reads the pressure anti-blockage status flag. Since it is in an invalid state, the system normally executes the discharge control quantity generation step based on the liquid level parameters. According to the deviation between the current liquid level parameters and the preset liquid level control threshold center value of 1500mm, the valve opening is adjusted in real time to maintain the stability of the liquid level inside the crystallizer. The initial steady-state liquid level is 1510mm, which is within the normal fluctuation range of the preset liquid level control threshold center value, and meets the typical working condition requirements for continuous and stable production of the crystallizer.When crystals begin to accumulate at the conical bottom of the crystallizer, increasing the flow resistance in the discharge pipeline, the pressure parameter in the discharge pipeline gradually rises. The controller collects the pressure parameter in real time with a sampling period of 0.5 seconds. When the collected pressure parameter reaches 0.58 MPa, the controller compares it with the preset pressure threshold of 0.5 MPa and determines that the pressure parameter has exceeded the threshold, indicating a tendency for crystal blockage at the valve. Therefore, it immediately executes the anti-blockage intervention start procedure: first, the pressure anti-blockage status flag is set from an invalid state to an effective state, marking the system entering the anti-blockage intervention mode; then, at the beginning of the next control cycle, the controller reads that the pressure anti-blockage status flag is in an effective state. The process of generating discharge control volume based on liquid level parameters is immediately suspended, and the valve opening is no longer adjusted according to liquid level deviation to avoid conflict between liquid level control commands and anti-clogging intervention commands. At the same time, the controller calculates that the deviation of the pressure parameter from the preset pressure threshold is 0.08MPa. Based on the preset basic anti-clogging opening increment coefficient, which is to increase the opening by 2% for every 0.01MPa exceeding the threshold, the basic anti-clogging opening increment is calculated to be 16%. The valve opening is increased from the current 40% to 56%, and an opening command is issued to the actuator of the upward-expanding automatic discharge valve to drive the valve core to move upward to increase the valve opening, increase the discharge flow to flush away the crystals accumulated at the valve, and alleviate the clogging trend. During the anti-blocking intervention, although the controller paused the active adjustment function of the liquid level control, it continued to collect the liquid level parameters inside the crystallizer in real time with a sampling period of 0.5 seconds and perform the liquid level monitoring function. When the liquid level parameter was detected to gradually decrease from the initial 1510mm to 1450mm, the controller compared the current liquid level parameter of 1450mm with the preset lower limit of the liquid level control threshold of 1432mm. It was determined that the liquid level parameter had a margin of only 18mm with the lower limit of the liquid level control threshold, which had entered the preset liquid level alarm threshold range and reached the preset liquid level alarm trigger condition. Therefore, a liquid level alarm signal was immediately generated and the liquid level protection mechanism was activated, limiting the maximum value of the anti-blocking opening increment to 3%. That is, in subsequent anti-blocking adjustments, the single opening increment shall not exceed 3%. If the pressure parameter is still in a high state of 0.55MPa, the controller will only increase the valve opening from 56% to 59% at a slower rate to continue to alleviate the blockage and prevent the liquid level from dropping further due to excessive increase in opening and causing liquid level loss of control.As the anti-blocking intervention continues, the pressure parameter in the discharge pipeline gradually decreases due to the increased valve opening. The controller continuously monitors the pressure parameter. When the collected pressure parameter drops to 0.48 MPa, it is compared with the preset pressure threshold of 0.5 MPa. It is determined that the pressure parameter has returned below the threshold, and the blockage trend has been eliminated. Therefore, the anti-blocking exit procedure is immediately executed: First, the pressure anti-blocking status flag is reset from an active state to an inactive state, indicating that the system has exited the anti-blocking intervention mode. Then, at the start of the next control cycle, the controller reads that the pressure anti-blocking status flag is inactive and resumes the step of generating the discharge control quantity based on the liquid level parameter. Simultaneously, the controller activates a buffer time window and sets the buffer duration to 10 seconds to achieve a smooth transition from the anti-blocking mode to the liquid level control mode. The controller reads the current liquid level parameter. Given a current valve opening of 59% and a current level of 1465mm, the target opening is calculated to be 48% based on the deviation of -35mm between the current level parameter and the preset level control threshold center value of 1500mm. Since the target opening differs from the current opening by 11%, the controller limits the change in opening to within 2% for each adjustment within a 10-second buffer window. The adjustment process is broken down into multiple executions, with the valve opening gradually decreasing at each control cycle interval, from 59% to 57%, 55%, 53%, 51%, 49%, and finally 48%. Each adjustment step is completed within the buffer window. After the buffer window ends, the controller removes the adjustment range limitation, resumes normal level control response, and dynamically calculates and executes valve opening adjustment based on the real-time level deviation, gradually returning the level to the target value of 1500mm. Through the complete control process described above, the system prioritizes anti-blocking intervention and suspends liquid level control when the pressure parameter exceeds the threshold. The mutual exclusion execution of the two control modes is achieved through the status flag bit. While ensuring the priority of anti-blocking control, the system also takes into account the safety of liquid level operation, and realizes the coordinated operation of anti-blocking intervention and liquid level stability control.

[0055] This invention sets a pressure anti-blocking status flag. When the pressure parameter exceeds a threshold, the flag is immediately set to an active state, pausing the generation step of the discharge control quantity based on the liquid level parameter. Simultaneously, anti-blocking intervention is initiated, achieving mutually exclusive execution of pressure anti-blocking and liquid level control. This effectively solves the control command conflict problem that may occur when the two share the same valve actuator. By continuously monitoring the liquid level parameter during anti-blocking intervention, a liquid level protection mechanism is activated when the liquid level drops to a preset alarm threshold, limiting the maximum value of the anti-blocking opening increment. This prevents the liquid level from dropping too quickly due to excessive opening and causing liquid level runaway, prioritizing anti-blocking while ensuring liquid level safety. By setting a buffer time window after the blockage is cleared, the opening adjustment step size when restoring liquid level control is limited to within a preset maximum step size, achieving a smooth transition from anti-blocking mode to liquid level control mode and avoiding the impact of sudden opening changes on the system. The above-mentioned technical means work together to systematically solve the coordination problem between pressure anti-blocking and liquid level control from three aspects: control mutual exclusion, liquid level protection, and smooth switching, which significantly improves the operational stability and safety of the crystallizer discharge system under blockage conditions.

[0056] It should be further explained that the intervention in this embodiment to adjust the opening of the upward-expanding automatic discharge valve specifically includes: S321. Real-time acquisition of pressure parameters in the discharge pipeline, recording the time of each acquisition, and constructing a time series of pressure parameters; S322. Using a preset sampling period as the time interval, calculate the rate of change of the pressure parameter based on the difference between the pressure parameter collected at the current moment and the pressure parameter collected at the previous moment. The rate of change is the amount of change of the pressure parameter per unit time, specifically: S322a. Set the sliding window length, wherein the sliding window length is a preset number of continuous sampling periods; S322b: Collect multiple pressure parameters within a sliding window, calculate the difference between the first and last pressure parameters within the window, divide it by the time span corresponding to the window, and obtain the smoothed rate of change to eliminate the influence of single sampling noise on the rate of change calculation.

[0057] S323. Set a rate of change threshold, wherein the rate of change threshold is a constant greater than zero, used to distinguish between normal fluctuations and rapid upward trends of pressure parameters; S324. Compare the currently collected pressure parameters with the preset pressure threshold, and compare the calculated rate of change with the rate of change threshold. S325. If the current pressure parameter is less than or equal to the preset pressure threshold, the discharge pipeline is determined to be in normal flow state and no anti-blocking intervention is performed. S326. If the current pressure parameter is greater than the upper limit of the anti-blocking dead zone interval and the pressure change rate is less than or equal to the preset change rate threshold, it is determined that the pressure parameter exceeds the threshold but the upward trend is slow. Regular anti-blocking intervention is performed. Based on the pressure deviation value of the actual pressure parameter of the discharge pipeline exceeding the upper limit of the anti-blocking dead zone interval, combined with the preset basic anti-blocking opening increment coefficient, the basic opening increment of the regular anti-blocking is calculated and generated. The basic opening increment of the regular anti-blocking is then superimposed on the current opening value of the upward-expanding automatic discharge valve before execution. S327. If the current pressure parameter is greater than the upper limit of the anti-blocking dead zone interval and the pressure change rate is greater than the preset change rate threshold, then the pressure parameter is determined to exceed the threshold and show a rapid upward trend. Emergency anti-blocking intervention is executed. The corresponding emergency opening increment coefficient is determined according to the interval to which the pressure change rate belongs. The emergency opening increment coefficient is calculated by multiplying the basic anti-blocking opening increment coefficient by the emergency opening increment coefficient. The emergency opening increment coefficient is multiplied by the pressure deviation value of the actual pressure parameter of the discharge pipeline exceeding the upper limit of the anti-blocking dead zone interval to obtain the emergency anti-blocking opening increment. The emergency anti-blocking opening increment is then added to the current opening value of the upward-expanding automatic discharge valve before execution. Specifically: S327a. Multiple continuous pressure change rate intervals are preset, and each pressure change rate interval corresponds to a different emergency opening increment coefficient multiple. The emergency opening increment coefficient multiple increases with the increase of the pressure change rate interval, and the emergency opening increment coefficient corresponding to each change rate interval is greater than the basic anti-blocking opening increment coefficient used in conventional anti-blocking intervention. S327b. Based on the calculated rate of change, determine the range of the rate of change to which the rate of change belongs, and read the emergency opening increment coefficient multiplier corresponding to the range of the rate of change. S327c: Calculate the pressure deviation value that exceeds the upper limit of the anti-blocking dead zone interval, and multiply the pressure deviation value by the emergency opening increment coefficient to obtain the emergency anti-blocking opening increment.

[0058] S328. After the emergency blocking intervention is executed, continue to collect pressure parameters in real time and calculate the rate of change. When the pressure parameters return to below the preset pressure threshold, restore the normal control mode.

[0059] S329. Set the upper limit value of the valve opening, wherein the upper limit value is the maximum allowable opening of the upward-expanding automatic discharge valve; S3210. After adding the emergency opening increment to the current opening value, compare the added result with the opening upper limit value. If the added result is greater than the opening upper limit value, the opening upper limit value is output as the final opening command; if the added result is less than or equal to the opening upper limit value, the added result is output as the final opening command.

[0060] Next, a specific and complete calculation example will be used to illustrate the entire process. This example is only to illustrate the feasibility at the computational level and does not represent actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, during the normal operation of the crystallizer, the controller collects the pressure parameters of the discharge pipeline in real time at a preset sampling period of 0.5 seconds and constructs a pressure parameter time series. When the pressure parameter is at a normal value, for example, the current pressure parameter is 0.48 MPa, since this pressure parameter is less than or equal to the preset pressure threshold of 0.5 MPa, the controller determines that the discharge pipeline is in a normal flow state and does not perform anti-blocking intervention. When the pressure parameter rapidly increases from the normal value of 0.48 MPa, the controller uses a sliding window method to eliminate single-sampling noise. The sliding window length is set to 5 consecutive sampling periods. The pressure parameters collected within the window are 0.51 MPa, 0.53 MPa, 0.56 MPa, 0.58 MPa, and 0.59 MPa, respectively. The difference between the first and last pressure parameters within the window is calculated to be 0.08 MPa. The time span corresponding to the window is 2 seconds, resulting in a smoothed pressure change rate of 0.04 MPa / s. At this point, the current pressure parameter is 0.59 MPa, which exceeds the upper limit of the anti-blocking dead zone of 0.55 MPa. Furthermore, the calculated pressure change rate of 0.04 MPa / s is greater than the preset change rate threshold of 0.01 MPa / s. The controller determines that the current pressure parameter exceeds the threshold and is showing a rapid upward trend, and immediately executes emergency anti-blocking intervention. Based on the preset continuous pressure change rate range, a pressure change rate of 0.04 MPa / s falls into the second range (above 0.02 MPa / s). The emergency opening increment coefficient multiplier corresponding to this change rate range is read as 1.5 times. The pressure deviation value exceeding the upper limit of the anti-clogging dead zone range is calculated to be 0.04 MPa. Based on the preset basic anti-clogging opening increment coefficient (each 0.01 MPa deviation corresponds to a 2% increase in the opening of the upward-expanding automatic discharge valve), the basic opening increment of the conventional anti-clogging valve is calculated to be 8%. By multiplying the basic anti-clogging opening increment coefficient by the emergency opening increment coefficient multiplier, the emergency opening increment coefficient is obtained (i.e., each 0.01 MPa deviation corresponds to a 3% increase in opening). The pressure deviation value of 0.04 MPa is multiplied by the emergency opening increment coefficient to obtain an emergency anti-clogging opening increment of 12%. The current opening value of the upward-expanding automatic discharge valve is 40%. The emergency anti-clogging opening increment of 12% is added to the current opening value to obtain a superimposed opening value of 52%. The controller also compares the superimposed opening value of 52% with the preset upper limit of valve opening of 90%. Since 52% is less than 90%, 52% is output as the final opening command to the actuator of the upward-expanding automatic discharge valve. The actuator drives the upward-expanding automatic discharge valve to increase the opening to flush away the accumulated crystals.After the emergency anti-blockage intervention is executed, the controller continues to collect pressure parameters in real time and calculate the pressure change rate. When the pressure parameter drops to 0.48 MPa and returns to below the preset pressure threshold of 0.5 MPa, it is determined that the crystal blockage trend has been eliminated, and the normal control mode is restored. Thus, when the pressure parameter rises sharply, the emergency anti-blockage intervention is triggered by judging the pressure change rate, and a faster response with a larger opening increment is achieved, effectively preventing the blockage of the discharge pipeline from worsening.

[0061] It should be further explained that in this embodiment, the operating parameters of the small stirring blade are determined based on the specific value of the accumulation detection parameter, specifically including: S401. Set a moving average window, the length of which is a preset number of continuous sampling periods, and the sampling period is the time interval between two adjacent data collections from the material accumulation detection sensor. S402. During each sampling period, the accumulation detection parameters of the material at the bottom of the crystallizer cone are collected, and the collected accumulation detection parameters are stored in the moving average window in chronological order to form a time series of accumulation detection parameters. S403. When the number of material accumulation detection parameters stored in the moving average window reaches the preset window length, calculate the arithmetic mean of the accumulation detection parameters of all materials in the window to obtain the smoothed accumulation detection value, specifically: S403a: If the number of material accumulation detection parameters stored in the moving average window does not reach the preset window length, the accumulation judgment is temporarily suspended, and parameters are collected until the window is filled. S403b: When the window is full, the window is updated and the smoothed stacking detection value is calculated every time a new material stacking detection parameter is collected, to ensure the continuity and real-time performance of stacking determination.

[0062] S404. Compare the smooth accumulation detection value with the preset accumulation judgment threshold. If the smooth accumulation detection value is less than or equal to the preset accumulation judgment threshold, it is determined that there is no crystalline material accumulation at the bottom of the cone, and the small stirring blade is kept in a stopped state. S405. If the smooth accumulation detection value is greater than the preset accumulation judgment threshold, it is determined that there is crystalline material accumulation at the bottom of the cone. The operating parameters of the small stirring blade are determined based on the specific value of the smooth accumulation detection value. These operating parameters include stirring speed, single operation duration, and start-stop cycle. The stirring speed and single operation duration are positively correlated with the smooth accumulation detection value, while the single stop duration is negatively correlated with the smooth accumulation detection value. The overall stirring intensity maintains a positive correlation with the accumulation detection parameters. Specifically: S405a. Multiple accumulation detection value ranges are preset, and each accumulation detection value range corresponds to a different stirring speed, single operation time and start-stop cycle. The stirring speed and single operation time increase as the accumulation detection value range increases, and the single stop time decreases as the accumulation detection value range increases. S405b. Compare the calculated smooth stacking detection value with each stacking detection value interval to determine the stacking detection value interval to which the smooth stacking detection value belongs. S405c: Read the stirring speed, single operation duration and start-stop cycle corresponding to the accumulation detection value range, as the operating parameters of the small stirring blade.

[0063] S406. The determined stirring speed, single operation time and start-stop cycle are sent to the drive mechanism of the small stirring blade to control the small stirring blade to operate according to the operating parameters and apply stirring force to the material at the bottom of the cone to disperse the accumulated material. S407. During the operation of the small stirring blade, the material accumulation detection parameters continue to be collected in each sampling cycle, and the data in the moving average window is updated. The latest collected parameters are stored in the window in the first-in-first-out manner, while the earliest collected parameters in the window are removed, so that the window always contains the latest preset number of accumulation detection parameters. S408. After each sampling period, recalculate the arithmetic mean of all stacking detection parameters within the moving average window to obtain updated smoothed stacking detection values. S409. Compare the updated smooth accumulation detection value with the preset accumulation judgment threshold. If the updated smooth accumulation detection value is less than or equal to the preset accumulation judgment threshold, the accumulation is determined to be eliminated and the small stirring blade is stopped. If the updated smooth accumulation detection value is still greater than the preset accumulation judgment threshold, the small stirring blade continues to operate, and the operating parameters of the small stirring blade are dynamically adjusted according to the updated smooth accumulation detection value.

[0064] Next, a specific complete example will be used to illustrate the whole process. The example is only to illustrate the feasibility of the calculation and does not represent the actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, the moving average window length is set to 5 consecutive sampling periods, the sampling period is 2 seconds, and the preset accumulation judgment threshold is 100Pa. Over five consecutive sampling periods, the controller sequentially collects the accumulation detection parameters of the material at the bottom of the crystallizer cone at 95 Pa, 98 Pa, 102 Pa, 105 Pa, and 108 Pa, and stores them in a moving average window in chronological order, forming a time series of accumulation detection parameters. At this point, the number of accumulation detection parameters stored in the moving average window has reached the preset window length of 5. The arithmetic mean of all accumulation detection parameters within the window is calculated as (95 + 98 + 102 + 105 + 108) / 5 = 101.6 Pa, yielding a smoothed accumulation detection value of 101.6 Pa. This smoothed accumulation detection value of 101.6 Pa is compared with the preset accumulation judgment threshold of 100 Pa. Because the smoothed accumulation detection value is greater than the preset accumulation judgment threshold, it is determined that there is accumulation of crystalline material at the bottom of the crystallizer cone.

[0065] Multiple stacking detection value ranges are pre-defined, including: The operating parameters corresponding to the 100Pa to 120Pa range are: stirring speed 60 rpm, single operation time 30 seconds, and single stop time 60 seconds; The operating parameters corresponding to the 120Pa to 150Pa range are: stirring speed 90 rpm, single operation time 60 seconds, and single stop time 30 seconds.

[0066] The currently calculated smooth accumulation detection value is 101.6 Pa, falling within the 100 Pa to 120 Pa range. The corresponding operating parameters for this range are read, and the operating parameters for the small stirring blade are determined as follows: stirring speed 60 rpm, and a start-stop cycle consisting of a 30-second single operation and a 60-second single stop. The determined stirring speed, single operation duration, and start-stop cycle are sent to the drive mechanism of the small stirring blade to control it to start operating according to the aforementioned operating parameters.

[0067] During the operation of the small stirring blade, the controller continues to collect new accumulation detection parameters every 2 seconds. Assuming the subsequently collected accumulation detection parameters are 106 Pa, 104 Pa, 100 Pa, 98 Pa, and 95 Pa, each time a new parameter is collected, the data in the moving average window is updated using a first-in, first-out (FIFO) method. That is, the earliest collected parameter in the window is removed, and the latest collected parameter is added to the window, ensuring that the window always contains the latest five accumulation detection parameters. After the window is updated, the arithmetic mean of all accumulation detection parameters in the window is recalculated to obtain the updated smoothed accumulation detection value. When the parameters in the window are successively updated to 106 Pa, 104 Pa, 100 Pa, 98 Pa, and 95 Pa, the calculated arithmetic mean is (106 + 104 + 100 + 98 + 95) / 5 = 100.6 Pa. The updated smooth accumulation detection value of 100.6 Pa is compared with the preset accumulation judgment threshold of 100 Pa. Since it is still greater than the preset accumulation judgment threshold, the accumulation is determined to have not been eliminated. The small stirring blade continues to operate, and the corresponding accumulation detection value range is re-determined based on the updated smooth accumulation detection value of 100.6 Pa. Because 100.6 Pa is still within the range of 100 Pa to 120 Pa, the read operating parameters are consistent with the current operating parameters, so the original operating parameters are maintained unchanged. After continued acquisition and updating, when the parameters in the window become 100 Pa, 98 Pa, 95 Pa, 92 Pa, and 90 Pa, the arithmetic mean is recalculated as (100+98+95+92+90) / 5=95 Pa. The updated smooth accumulation detection value of 95 Pa is compared with the preset accumulation judgment threshold of 100 Pa. Since the smooth accumulation detection value is less than the preset accumulation judgment threshold, the accumulation of crystallizing material at the bottom of the crystallizer cone is determined to have been eliminated, and the controller stops the small stirring blade.

[0068] With the sliding average window mechanism of this embodiment, even if the accumulation detection parameters fluctuate drastically within a single sampling period, the accumulation judgment result will not change immediately. Instead, the result is smoothed by the arithmetic mean of multiple accumulation detection parameters within the window. This effectively avoids frequent changes in the operating parameters of the small stirring blades due to instantaneous fluctuations, reduces the operating load of the drive mechanism, and ensures the stability of the stirring action.

[0069] It should be further explained that, in this embodiment, when the small agitator blades are operating according to the determined operating parameters, the step of comparing the discharge pipeline pressure parameters with the preset pressure threshold and adjusting the opening of the upward-expanding automatic discharge valve is paused until the small agitator blades' operating cycle ends. Specifically, this includes: S501. Set the small stirring blade running status flag bit, the small stirring blade running status flag bit includes running status and stop status, the initial status is stop status; S502. In the preset accumulation judgment threshold comparison step, if the accumulation detection parameter is greater than the preset accumulation judgment threshold, it is determined that there is crystalline material accumulation at the bottom of the cone. Before sending the control command to the drive mechanism of the small stirring blade, the running status flag of the small stirring blade is switched to the running status. S503. Send a control command to the drive mechanism of the small stirring blade to control the small stirring blade to start running according to the determined operating parameters; S504. During the operation of the small agitator blade, before the controller performs the step of comparing the pressure parameters of the discharge pipeline with the preset pressure threshold, it first reads the running status flag bit of the small agitator blade. S505. If the small agitator blade running status flag is in running status, the pressure anti-blockage opening intervention adjustment action will be paused, and the current opening of the upward-expanding automatic discharge valve will remain unchanged. The controller will continuously collect the discharge pipeline pressure parameters and perform threshold comparison and judgment normally, cache and record abnormal events of pressure exceeding the threshold, and continuously monitor the small agitator blade running status flag. S506. If the small stirring blade running status flag is in the stopped state, the normal procedure is to compare the discharge pipeline pressure parameter with the preset pressure threshold and adjust the opening of the upper automatic discharge valve according to the comparison result. S507. During the operation of the small stirring blade, the cumulative operating time of the small stirring blade is continuously monitored according to the single operation time and single stop time in the determined operating parameters. When the cumulative operating time reaches the single operation time, the small stirring blade is controlled to stop operating and the running status flag of the small stirring blade is switched to the stop state. After the single stop time ends, the running status flag of the small stirring blade is switched back to the running state and the small stirring blade is restarted to operate according to the determined operating parameters. S508. When the pressure anti-blocking opening intervention adjustment action is paused during the operation of the small stirring blade, the controller continuously collects the pressure parameters of the discharge pipeline in real time and simultaneously completes the threshold comparison and judgment. Events exceeding the preset pressure threshold and the corresponding pressure parameter values ​​are fully recorded, and anti-blocking demand cache records are generated. S509. When the small stirring blade running status flag is switched to the stop state, when restoring the pressure anti-blocking control step, the anti-blocking demand cache record is read first. If there is an unprocessed over-threshold event in the anti-blocking demand cache record, the step of intervening to adjust the opening of the upper automatic discharge valve is immediately executed according to the pressure parameters in the cache record.

[0070] Next, a specific and complete calculation example will be used to illustrate the entire control process described above. This example is only used to verify the feasibility at the computational level and does not represent actual production values. Specific parameter values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, in this embodiment, the preset accumulation judgment threshold is 100 Pa, and the operating parameters of the small stirring blade are set as follows: stirring speed 60 rpm, single operation duration 30 seconds, single stop duration 60 seconds, and the small stirring blade operating status flag is initially set to the stop state. When the material accumulation detection parameter collected by the controller is 120 Pa (greater than the preset accumulation judgment threshold of 100 Pa), it is determined that there is material accumulation at the bottom of the crystallizer cone. The small stirring blade operating status flag is then switched to the operating state, and a control command is sent to the small stirring blade drive mechanism to control the small stirring blade to start operating at a speed of 60 rpm for a duration of 30 seconds. During the 30 seconds that the small agitator blades are running, before executing the pressure anti-blocking step in each control cycle, the controller first reads the small agitator blade's running status flag. If it detects that the blades are running, it pauses the comparison of the discharge pipeline pressure parameters with the preset pressure threshold. Simultaneously, it pauses the adjustment of the opening of the upward-expanding automatic discharge valve based on this comparison result, maintaining the upward-expanding automatic discharge valve at its current 45% opening. During this period, the controller continues to collect the discharge pipeline pressure parameters at 0.5-second intervals. When the pressure parameter gradually rises from 0.48 MPa to 0.55 MPa (exceeding the preset pressure threshold of 0.5 MPa), because the small agitator blades are running, the controller does not perform valve opening adjustment; instead, it generates an anti-blocking requirement cache record, detailing the pressure exceeding the threshold event and the corresponding pressure parameters. After the 30-second operation period, the small agitator blade stops operating, and the controller switches the small agitator blade's operating status flag to the stop state. Simultaneously, it immediately reads the anti-blocking demand cache record and detects an unprocessed pressure over-threshold event (maximum pressure reaching 0.55 MPa). Based on this over-threshold pressure parameter, it intervenes and adjusts the opening of the upward-expanding automatic discharge valve from 45% to 55% to alleviate pipeline blockage. Subsequently, the small agitator blade enters a 60-second stop period. During this time, the small agitator blade's operating status flag remains in the stop state, the pressure anti-blocking steps are executed normally, and the opening of the upward-expanding automatic discharge valve is dynamically adjusted based on the real-time collected pressure parameters. After the 60-second stop period, the small agitator blade enters another 30-second operating cycle. The controller switches the small agitator blade's operating status flag back to the operating state and pauses the pressure anti-blocking related operations again. This cycle repeats until the accumulation detection parameter drops below the preset accumulation judgment threshold (100 Pa), at which point the small agitator blade stops operating.

[0071] If the pressure parameter of the discharge pipeline continues to rise to 0.65MPa during the operation of the small agitator blades, reaching the preset pressure alarm threshold of 0.6MPa, the controller will immediately generate a pressure abnormality alarm signal and send it to the human-machine interface to prompt the operator to pay attention to the pressure status. At the same time, the small agitator blades will continue to operate to ensure that the agitation and unblocking operation is not interrupted, so as to avoid the accumulation from being aggravated due to the interruption of agitation.

[0072] It should be further noted that the operating parameters of the small stirring blade in this embodiment also include the maximum continuous operating time, specifically including: S511. Preset the maximum continuous running time T_max and the cooling waiting period T_cool, wherein the maximum continuous running time T_max is the maximum allowable time for the small stirring blade to operate continuously in a single cycle, and the cooling waiting period T_cool is the cooling time of the drive mechanism that needs to be waited for after the small stirring blade is forcibly stopped. S512. When the small stirring blade starts running, record the start time t_start and start accumulating the continuous running time t_run; S513. Before the cumulative continuous running time t_run reaches the maximum continuous running time T_max, control the small stirring blade to operate normally according to the predetermined running parameters. S514. When the cumulative continuous running time t_run reaches the maximum continuous running time T_max, the small stirring blade is forcibly stopped. Regardless of whether the current accumulation detection parameter is still greater than the preset accumulation judgment threshold, a forced stop operation is performed, and the running status flag of the small stirring blade is simultaneously switched to the stop state. Specifically: S514a. Before the cumulative continuous running time t_run reaches the maximum continuous running time T_max, a pre-set warning time threshold T_warn is set. When t_run reaches T_max minus T_warn, a running time warning signal is generated. S514b: Send the runtime warning signal to the human-machine interface of the control system to remind the operator that the small stirring blade is about to reach the maximum continuous runtime, so as to predict the working condition in advance.

[0073] S515. After forcibly stopping the small stirring blade, start the cooling waiting period T_cool timer to keep the small stirring blade in a stopped state and allow the drive mechanism to cool naturally. Specifically: S515a. Set the cooling status flag bit, which includes a cooling status and a non-cooling status. The initial status is the non-cooling status. When the cooling wait cycle timer starts, the cooling status flag bit is switched to the cooling status simultaneously. S515b: During the cooling state, the controller suspends the execution of the start control command for the small stirring blade until the cooling waiting cycle timer ends and the cooling state flag is reset to the non-cooling state.

[0074] S516. After the cooling waiting period T_cool ends, reset the cooling status flag to the non-cooling status, re-collect the material accumulation detection parameters at the bottom of the crystallizer cone, and compare the re-collected material accumulation detection parameters with the preset accumulation judgment threshold. S517. If the newly collected material accumulation detection parameters are greater than the preset accumulation judgment threshold, it is determined that there is still crystalline material accumulation at the bottom of the cone. The small stirring blade is restarted, and the running status flag of the small stirring blade is switched to running status. The running parameters of the small stirring blade are re-determined according to the current accumulation detection parameters, and the cumulative value of continuous running time is reset and the timing is restarted. Specifically: S517a. When restarting the small stirring blade, the stirring speed, single operation time, and single stop time are re-determined based on the newly collected material accumulation detection parameters. Among them, the stirring speed and single operation time are positively correlated with the newly collected accumulation detection parameters, the single stop time is negatively correlated with the newly collected accumulation detection parameters, and the overall stirring intensity is positively correlated with the accumulation detection parameters. S517b If the re-acquired accumulation detection parameters are lower than before the forced stop, the stirring speed should be reduced, the single operation time shortened, and the single stop time extended accordingly; if the re-acquired accumulation detection parameters are still at a high level, the stirring speed should be increased, the single operation time extended, and the single stop time shortened accordingly.

[0075] S518. If the newly collected material accumulation detection parameters are less than or equal to the preset accumulation judgment threshold, it is determined that there is no crystallized material accumulation at the bottom of the cone, the small stirring blade is kept in a stopped state, and the cumulative value of continuous running time and the cooling status flag are reset synchronously.

[0076] Next, a specific complete example will be used to illustrate the entire process. This example is only to illustrate the feasibility at the computational level and does not represent actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, in this embodiment, the preset maximum continuous running time T_max is 300 seconds, the cooling waiting period T_cool is 120 seconds, and the warning time threshold T_warn is 60 seconds. When the material accumulation detection parameter at the bottom of the crystallizer cone is 120Pa, which is greater than the preset accumulation judgment threshold of 100Pa, it is determined that there is accumulation of crystallizing material. The controller sends a control command to the drive mechanism of the small stirring blade to start the small stirring blade, and simultaneously records the start time t_start, begins to accumulate the continuous running time t_run, and sets the running status flag of the small stirring blade to the running status. When the accumulated continuous running time t_run reaches 240 seconds (i.e., T_max - T_warn = 300 - 60), the controller generates a running time warning signal and sends it to the human-machine interface of the control system, prompting the operator that "the small stirring blade is about to reach the maximum continuous running time, please pay attention to the accumulation status." When the cumulative continuous running time t_run reaches the maximum continuous running time T_max, i.e., 300 seconds, even though the real-time collected accumulation detection parameter is still 110Pa, which is greater than the preset accumulation judgment threshold of 100Pa, the controller still forcibly stops the small stirring blade and simultaneously switches the small stirring blade running status flag to the stop state. After the forced stop, the controller starts the cooling waiting period T_cool timer and switches the cooling status flag from the non-cooling state to the cooling state. During the 120-second cooling waiting period, the cooling status flag remains in the cooling state, the controller pauses the execution of the small stirring blade start control command, and the drive mechanism is in a natural cooling state. After the cooling waiting period ends, the controller resets the cooling status flag to the non-cooling state and re-collects the accumulation detection parameter of the material at the bottom of the crystallizer cone, at which time the collected value is 105Pa. The newly acquired accumulation detection parameter of 105 Pa is compared with the preset accumulation judgment threshold of 100 Pa. Since it is greater than the preset accumulation judgment threshold, it is determined that there is still crystalline material accumulation at the bottom of the cone. The controller restarts the small stirring blade, simultaneously switches the small stirring blade running status flag to running status, and resets the cumulative value of continuous running time t_run to zero, restarting the timing. At the same time, the running parameters of the small stirring blade are re-determined based on the newly acquired accumulation detection parameter of 105 Pa: since 105 Pa still falls within the accumulation detection value range of 100 Pa to 120 Pa, but is lower than the smooth accumulation detection value before the forced stop, according to the rules of step S517b, the stirring speed is reduced, the single running time is shortened, and the single stop time is extended. Specifically, the stirring speed is reduced from 60 rpm to 55 rpm, the single running time is shortened from 30 seconds to 28 seconds, and the single stop time is extended from 60 seconds to 65 seconds.If the accumulation detection parameter collected again after the cooling waiting period is 95Pa, since it is less than or equal to the preset accumulation judgment threshold of 100Pa, it is determined that there is no crystalline material accumulation at the bottom of the cone. The controller keeps the small stirring blade in a stopped state, does not perform a restart operation, and simultaneously clears the cumulative value of continuous running time t_run to zero, and keeps the cooling status flag in the non-cooling state.

[0077] It should be further explained that, in this embodiment, when adjusting the opening of the upward-expanding automatic discharge valve, a pressure anti-blocking status flag is generated. The liquid level control step reads this pressure anti-blocking status flag before generating the discharge control quantity. If the pressure anti-blocking status flag is valid, the step of generating the discharge control quantity based on the liquid level parameters is paused. Specifically, this includes: S601. Set the pressure anti-blockage status flag F_p. F_p includes an effective state and an invalid state. The initial state is invalid. Simultaneously set the maximum duration threshold of pressure anti-blockage and the flag abnormality verification cycle for fault-tolerant fallback control. S602. In the step of comparing the collected discharge pipeline pressure parameters with the upper limit of the anti-blockage dead zone, if the pressure parameters exceed the upper limit of the anti-blockage dead zone, it is determined that there is a tendency for crystal blockage at the valve. The pressure anti-blockage status flag F_p is immediately switched to the effective state, and the opening of the upward-expanding automatic discharge valve is adjusted. The start time of the effective state of the flag is recorded simultaneously, and the duration timer is started. S603. Before executing the step of generating the discharge control quantity based on the liquid level parameter in each control cycle, the pressure anti-blockage status flag bit F_p is read first, and the flag bit status fault tolerance check is executed synchronously. S604. If the read pressure anti-blocking status flag F_p is invalid and the verification is normal, continue to execute the step of generating the discharge control quantity based on the liquid level parameter, and transmit the generated discharge control quantity to the actuator of the upward-expanding automatic discharge valve. S605. If the pressure anti-blocking status flag F_p is valid, then pause the step of generating the discharge control quantity based on the liquid level parameter, keep the current anti-blocking adjustment opening of the upward automatic discharge valve unchanged, and continuously monitor the pressure anti-blocking status flag F_p and the discharge pipeline pressure parameter. Furthermore, in this embodiment, while the pressure anti-blocking status flag F_p is in an effective state, the duration of the flag is simultaneously verified: if the pressure parameter remains higher than the upper limit of the anti-blocking dead zone within a preset time threshold, the effective state of the pressure anti-blocking status flag F_p is maintained, and liquid level control is continuously suspended until the pressure parameter returns to below the preset pressure threshold; if the duration of the effective state of the flag exceeds the preset maximum duration threshold for pressure anti-blocking, regardless of whether the pressure parameter returns to the normal range, the timeout fallback reset mechanism is triggered. In a specific embodiment, the value of the preset time threshold (i.e., the maximum duration threshold for pressure anti-blocking) needs to comprehensively consider the upper limit of the tolerance for blockage intervention in the discharge pipeline by the crystallization process, the safety margin for continuous operation of the upward-expanding automatic discharge valve actuator, and the risk of abnormal fluctuations in the liquid level of the crystallizer caused by prolonged suspension of liquid level control. For example, in this embodiment, the threshold is set to 60 seconds: when the pressure anti-blocking status flag is valid and lasts for more than 60 seconds, even if the pressure parameter of the discharge pipeline has not returned to below the preset pressure threshold, the control system will still forcibly release the pressure anti-blocking lock, restore the liquid level control, and simultaneously generate a pressure anti-blocking timeout alarm signal to prevent liquid level loss of control or equipment overload due to excessive anti-blocking intervention time. This value can be adjusted through on-site working condition calibration or statistical analysis of historical blockage data.

[0078] S606. After intervening to adjust the opening of the automatic discharge valve, continuously collect the pressure parameters of the discharge pipeline at a preset verification cycle, and compare the pressure parameters with the preset pressure threshold and the upper limit of the anti-blockage zone, and simultaneously verify the matching of the flag status with the pressure conditions. S607. When the pressure parameter returns to below the preset pressure threshold, it is determined that the crystal blockage trend has been eliminated. The pressure anti-blockage status flag F_p is switched to an invalid state, and the duration of the flag is simultaneously cleared. If the timeout fallback reset mechanism is triggered, a pressure anti-blockage timeout alarm signal is generated and sent to the human-machine interface. S608. After the pressure anti-blocking status flag F_p switches to the invalid state, the step of generating the discharge control quantity based on the liquid level parameter is resumed, and the discharge control quantity is regenerated according to the comparison result between the current liquid level parameter inside the crystallizer and the preset liquid level control threshold. Specifically: S608a. When the pressure anti-blocking status flag F_p switches from an effective state to an ineffective state and liquid level control is restored, a buffer time window T_buf is set, the duration of which is a preset buffer time. If the state switch is triggered by a timeout fallback reset, the buffer time window duration is extended accordingly, and the opening adjustment rate is reduced. S608b: Within the buffer time window T_buf, limit the adjustment range of the discharge control quantity generated based on the liquid level parameter, and limit the opening change of each adjustment to within the preset maximum step size; After the buffer time window T_buf ends, the adjustment range limitation is lifted, and the normal liquid level control adjustment response is restored.

[0079] Next, a specific and complete example will be used to illustrate the entire process. This example is only to illustrate the feasibility at the computational level and does not represent actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example: In this embodiment, the pressure anti-blocking status flag F_p is initially in an invalid state, the preset pressure threshold is 0.5MPa, the upper limit of the anti-blocking dead zone is 0.55MPa, the preset liquid level control threshold is 1500mm, the preset maximum duration threshold for pressure anti-blocking is 60 seconds, the flag verification cycle is 0.5 seconds, the normal operating condition buffer time window is 10 seconds, the extended buffer time window for timeout reset is 15 seconds, and the maximum step size for a single adjustment is 2%.

[0080] Abnormal fault-tolerant operating conditions: During the operation of the crystallizer, the pressure parameter of the discharge pipeline rises to 0.58MPa, exceeding the upper limit of the anti-blocking dead zone of 0.55MPa. The controller immediately switches the pressure anti-blocking status flag F_p to the effective state, records the start time of the flag, intervenes in the anti-blocking adjustment to increase the valve opening from 40% to 56%, and simultaneously suspends the liquid level control step to avoid control command conflicts.

[0081] During the continuous anti-blocking intervention, due to the stubborn crystal agglomeration, the pressure parameter remained fluctuating in the range of 0.52-0.56 MPa for a long time and never fully returned to the preset pressure threshold of 0.5 MPa. The effective state of the flag bit lasted for 60 seconds, triggering the preset maximum duration threshold for pressure anti-blocking. The controller immediately executed the timeout fallback reset mechanism: switching the pressure anti-blocking status flag bit F_p to the invalid state, generating a pressure anti-blocking timeout alarm signal and sending it to the human-machine interface to prompt the operator to check the blockage on-site.

[0082] After the flag is switched to an invalid state, the controller initiates a 15-second extended buffer time window and resumes the liquid level control procedure. The current liquid level parameter is read as 1442mm, which deviates from the preset liquid level control threshold of 1500mm by -58mm, and the target opening is calculated to be 42%. Within the 15-second buffer window, the controller gradually adjusts the valve opening from 56% to 54%, 52%, 50%, 48%, 46%, 44%, and 42%, with a maximum single adjustment step of 2%, avoiding liquid level oscillations caused by sudden changes in opening throughout the process. After the buffer time window ends, the adjustment range limit is lifted, and the normal liquid level control response is restored.

[0083] It should be further explained that, in this embodiment, before sending a control command to the drive mechanism of the small stirring blade, the pressure parameters of the discharge pipeline are read first. If the pressure parameters exceed a preset pressure threshold, the control command is delayed until the pressure parameters return to the preset pressure threshold range before the small stirring blade is started. Specifically, this includes: S701. Set the pressure check status flag F_check, which includes a check in progress status and a pass status, with the initial status being the pass status. S702. In the preset accumulation judgment threshold comparison step, if the accumulation detection parameter is greater than the preset accumulation judgment threshold, it is determined that there is crystalline material accumulation at the bottom of the cone. Before sending the control command to the drive mechanism of the small stirring blade, the current discharge pipeline pressure parameter P_curr is read first. S703. Compare the read current discharge pipeline pressure parameter P_curr with the preset pressure threshold P_set; S704. If P_curr≤P_set, it is determined that the current discharge pipeline pressure is within the normal range and there is no tendency to blockage. The pressure check status flag F_check is set to the pass state, and a control command is immediately sent to the drive mechanism of the small stirring blade to start the small stirring blade. S705. If P_curr>P_set, it is determined that there is a tendency for crystal blockage in the current discharge pipeline. The pressure check status flag F_check is set to the check status, the control command is delayed, and the small stirring blade is prohibited from starting. S706. During the delay period, the pressure parameters of the discharge pipeline continue to be collected in real time at a preset sampling period, and the pressure parameters collected each time are continuously compared with the preset pressure threshold P_set. Specifically: S706a. During the delay period, the controller continues to collect the pressure parameters of the discharge pipeline in real time, and compares the collected pressure parameters with the preset pressure threshold, and records the duration and peak value of the pressure parameters exceeding the threshold. S706b: After the delay is lifted, if there is a pressure over-threshold cache record, the pressure over-threshold cache record will be sent to the human-machine interface of the control system at the same time as the small stirring blade is started, prompting the operator that there is an abnormal pressure before the start.

[0084] S707. When the collected pressure parameter P_curr drops below P_set, it is determined that the blockage trend has been eliminated. The pressure check status flag F_check is switched to the pass status, the delay is released, and a control command is sent to the drive mechanism of the small stirring blade to start the small stirring blade. S708. Set the maximum delay waiting time T_delay_max. Start the timer during the delay period. If the pressure parameter does not drop below the preset pressure threshold P_set within the maximum delay waiting time T_delay_max, then forcefully send a control command to start the small stirring blade and generate a pressure abnormality alarm signal.

[0085] S709. After the small stirring blades are started, if the start-up was delayed due to pressure exceeding the threshold, based on the pressure check results before start-up, the pressure parameters of the discharge pipeline will be compared with the preset pressure threshold once in the first control cycle after start-up. If the pressure parameters are still too high, the opening of the upward-expanding automatic discharge valve will be adjusted immediately.

[0086] S7010. When the operating parameters of the small stirring blade include start-stop cycles, the above pressure check steps shall be performed before the start of each single operation duration in each start-stop cycle to ensure that the discharge pipeline pressure is within the normal range before each start-up.

[0087] Next, a specific complete example will be used to illustrate the entire process. This example is only to illustrate the feasibility at the computational level and does not represent actual values. The specific values ​​can be determined by those skilled in the art through simulation experiments or physical experiments. For example, in this embodiment, the preset accumulation judgment threshold is 100 Pa, the preset pressure threshold P_set is 0.5 MPa, the maximum delay waiting time T_delay_max is 60 seconds, and the pressure check status flag F_check is initially in the pass state. When the material accumulation detection parameter is 120 Pa, which is greater than the preset accumulation judgment threshold of 100 Pa, the controller determines that there is crystalline material accumulation at the bottom of the cone and prepares to start the small agitator. Before sending the control command, the controller reads the current discharge pipeline pressure parameter P_curr as 0.58 MPa, which is greater than the preset pressure threshold of 0.5 MPa, and determines that there is a tendency for crystal blockage in the current discharge pipeline. The controller sets the pressure check status flag F_check to the checking state, delays the sending of the control command, and prohibits the small agitator from starting. During the delay period, the controller continuously collects pressure parameters at a cycle of 0.5 seconds and records the duration of pressure exceeding the threshold for 15 seconds, with a peak value of 0.58 MPa. When the pressure parameter gradually decreases during the delay period, and the collected pressure parameter is 0.48 MPa, which is lower than the preset pressure threshold of 0.5 MPa, the controller determines that the blockage trend has been eliminated, switches the pressure check status flag F_check to the pass state, cancels the delay, sends a control command to the small agitator drive mechanism to start the small agitator, and simultaneously sends the pressure exceeding the threshold cache record to the human-machine interface, prompting "Pressure reached 0.58 MPa before startup, lasting for 15 seconds". If the pressure parameter does not drop below 0.5 MPa during the delay period, and the delay time reaches 60 seconds, the small agitator is forcibly started, and a pressure abnormality alarm signal is generated. After the small agitator starts, the controller actively performs pressure comparison in the first control cycle. If the pressure parameter is still 0.52 MPa, it immediately intervenes to adjust, increasing the valve opening from the current 45% to 52% to alleviate the blockage trend. When the operating parameters of the small agitator blade include start-stop cycles, the pressure check steps described above should be performed before the start of each single operation to ensure that the pressure is within the normal range before each start-up.

[0088] This invention, by setting an anti-blocking dead zone, maintains a constant valve opening when the pressure parameter exceeds a preset pressure threshold but does not exceed the upper limit of the dead zone. This effectively avoids repeated valve actuation caused by frequent pressure fluctuations near the threshold, significantly extending the service life of the actuator. By introducing a sliding window to smoothly calculate the pressure change rate and pre-setting multiple change rate intervals corresponding to different emergency opening increment coefficients, it can quickly determine a larger opening increment based on the magnitude of the change rate when the pressure surges. This achieves adaptive switching from conventional anti-blocking to emergency anti-blocking, solving the problem that single opening adjustment cannot cope with sudden pressure surges, and significantly improving the timeliness and effectiveness of anti-blocking response. Furthermore, by setting a pressure anti-blocking status flag, it achieves mutually exclusive execution of anti-blocking and liquid level control, and monitors liquid level parameters and limits the maximum opening increment during anti-blocking intervention. By setting a buffer time window to limit the opening adjustment step size after the blockage is cleared, the problems of control command conflict, liquid level runaway, and mode switching shock are effectively solved, achieving a coordinated unity between anti-blockage priority and liquid level stability. Smoothing the accumulation detection parameters through a moving average window avoids frequent changes in the small agitator blade operating parameters caused by drastic fluctuations in a single sampling period, reducing the load on the drive mechanism. Pausing the pressure anti-blockage step and buffering over-threshold events during small agitator blade operation resolves the conflict between the two control objectives, while ensuring that pressure anomalies are not ignored due to monitoring pauses. Setting a maximum continuous running time and cooling waiting period prevents the drive mechanism from overheating and being damaged due to prolonged continuous operation. Checking pressure parameters before startup and delaying startup avoids exacerbating blockage when starting the small agitator blade when there is already a blockage trend. These technical measures work together to systematically solve the technical problem of blockage in the crystallizer discharge pipeline from multiple dimensions, including pressure fluctuation suppression, rapid response, control coordination, accumulation smoothing, equipment protection, and startup safety, significantly improving the operational stability, reliability, and intelligence level of the crystallizer discharge system.

[0089] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments under the guidance of the present invention without departing from the spirit and scope of the present invention. All of these variations are within the protection scope of the present invention.

Claims

1. A method for preventing blockage of the discharge pipeline of a crystallizer, characterized in that, The crystallizer is equipped with an upward-expanding automatic discharge valve at its lower part, and a set of small stirring blades is provided at the bottom of the crystallizer. The method includes: Real-time acquisition of internal liquid level parameters, discharge pipeline pressure parameters, and material accumulation detection parameters at the bottom of the cone; Preset liquid level control threshold and discharge pipeline pressure threshold; The discharge control quantity is generated based on the comparison result between the liquid level parameter and the preset liquid level control threshold, and the discharge control quantity is transmitted to the actuator of the upward automatic discharge valve to adjust the opening of the upward automatic discharge valve so that the liquid level parameter is stabilized within the preset liquid level control threshold range. At the same time, the collected discharge pipeline pressure parameters are compared with the preset pressure threshold. If the pressure parameters exceed the preset pressure threshold, it is determined that there is a tendency for crystal blockage at the valve. Then, with the goal of returning the pressure parameters to the preset pressure threshold range, the opening of the upward automatic discharge valve is adjusted until the pressure parameters return to the preset pressure threshold range. A preset material accumulation threshold is set. The accumulation detection parameters of the material at the bottom of the crystallizer cone are compared with the preset accumulation threshold. If the detection parameters are greater than the preset accumulation threshold, the operating parameters of the small stirring blade are determined based on the accumulation detection parameters, and a control command is sent to the drive mechanism of the small stirring blade to control the small stirring blade to operate according to the determined operating parameters.

2. The method for preventing blockage of the discharge pipeline of a crystallizer as described in claim 1, characterized in that, The discharge control quantity is generated based on the comparison result between the liquid level parameter and the preset liquid level control threshold, including: Calculate the liquid level deviation between the current liquid level parameter and the preset liquid level control threshold; Calculate the proportional component based on the liquid level deviation value, and perform time integration on the liquid level deviation value to obtain the integral cumulative amount. Calculate the integral component based on the integral cumulative amount. Set an integral limit value, compare the accumulated integral amount with the integral limit value, and if the absolute value of the accumulated integral amount is greater than the integral limit value, then perform an anti-integral saturation operation. When the sign of the liquid level deviation value is opposite to the sign of the integral accumulation, the integral lock is released, and time integration of the liquid level deviation value is resumed. The proportional component and the integral component are superimposed to obtain the discharge control quantity.

3. The method for preventing blockage of the crystallizer discharge pipeline as described in claim 2, characterized in that, The anti-integral saturation operation includes: The accumulated points are compared with the integration limit. If the absolute value of the accumulated points is greater than the integration limit, integration locking is performed. When performing integral locking, the cumulative integral amount is assigned to the integral limit value and given the same sign as the integral limit value. At the same time, the time integration of the liquid level deviation value is stopped, an integral locking flag is generated, and the current liquid level deviation value is recorded as the locking time deviation. During the integral locking period, the current liquid level deviation value is collected in real time at a preset sampling period, and the sign of the current liquid level deviation value is compared with the sign of the deviation at the locking time.

4. The method for preventing blockage of the crystallizer discharge pipeline as described in claim 3, characterized in that, The anti-integral saturation operation further includes: Set an integral recovery condition, wherein the integral recovery condition is: the sign of the current liquid level deviation value is opposite to the sign of the deviation at the locking time, and the absolute value of the current liquid level deviation value is greater than the preset deviation dead zone value. When the integral recovery condition is met, the integral lock flag is cleared, the integral lock is released, the time integration of the liquid level deviation value is resumed, and the cumulative integral at the moment of unlocking is used as the initial value for integration over a future preset time length. If the points lock period exceeds the preset maximum lock time, the points lock will be forcibly released, and the accumulated points will be cleared to zero before the points are restored.

5. The method for preventing blockage of the crystallizer discharge pipeline as described in claim 4, characterized in that, Calculate the proportional component based on the liquid level deviation value, including: A preset liquid level control threshold is provided, which includes an upper liquid level threshold and a lower liquid level threshold. The liquid level range between the upper liquid level threshold and the lower liquid level threshold is divided into multiple continuous liquid level intervals, and each liquid level interval corresponds to a preset proportional coefficient. Obtain the current liquid level parameter and compare it with the upper and lower liquid level thresholds. If the current liquid level parameter is greater than the upper liquid level threshold or less than the lower liquid level threshold, then directly execute the maximum or minimum opening adjustment.

6. The method for preventing blockage of the crystallizer discharge pipeline as described in claim 5, characterized in that, The calculation of the proportional component based on the liquid level deviation value also includes: If the current liquid level parameter is between the upper and lower limits of the liquid level threshold, then the liquid level range to which the current liquid level parameter belongs is determined, and the proportional coefficient corresponding to the liquid level range is read. Calculate the liquid level deviation between the current liquid level parameter and the preset liquid level control threshold, wherein the preset liquid level control threshold is the average of the upper liquid level threshold and the lower liquid level threshold; Multiplying the liquid level deviation value by the proportional coefficient yields the proportional control component.

7. The method for preventing blockage of the crystallizer discharge pipeline as described in claim 6, characterized in that, Determining the liquid level range to which the current liquid level parameter belongs includes: A hysteresis interval is set between two adjacent liquid level intervals. The width of the hysteresis interval is a preset boundary width value, and the center of the hysteresis interval coincides with the boundary line of the adjacent liquid level interval. The direction of change of the current liquid level parameter is obtained, and the direction of change includes a first direction of change from a low range to a high range and a second direction of change from a high range to a low range; If the current liquid level parameter changes in the first direction, the boundary switching point is set to the sum of the upper limit threshold of the adjacent liquid level interval and half the width of the hysteresis interval; if the current liquid level parameter changes in the second direction, the boundary switching point is set to the difference between the upper limit threshold of the adjacent liquid level interval and half the width of the hysteresis interval. The current liquid level parameter is compared with the boundary switching point. If the current liquid level parameter is greater than or equal to the boundary switching point, the current liquid level parameter is determined to belong to the high range; if the current liquid level parameter is less than the boundary switching point, the current liquid level parameter is determined to belong to the low range.

8. The method for preventing blockage of the discharge pipeline of a crystallizer as described in claim 7, characterized in that, The step of comparing the collected discharge pipeline pressure parameters with a preset pressure threshold includes: A preset pressure threshold P_set and a dead zone value ΔP are defined, wherein the dead zone value ΔP is a constant greater than 0; Based on the preset pressure threshold P_set and the dead zone value ΔP, an anti-blocking dead zone interval is constructed, wherein the lower limit of the anti-blocking dead zone interval is P_set and the upper limit is P_set+ΔP. Real-time acquisition of the discharge pipeline pressure parameter P_curr, and comparison of P_curr with the anti-blockage zone interval; If P_curr ≤ P_set, it is determined that the current discharge pipeline is in a normal flow state, and the current opening of the upward-opening automatic discharging valve is maintained; If P_set < P_curr ≤ P_set + ΔP, it is determined that the pressure of the current discharge pipeline is within the dead zone range, the current opening of the upward-opening automatic discharging valve is maintained unchanged, no anti-blocking adjustment is intervened, and at the same time, the step of generating a discharge control amount based on the liquid level parameter continues to be executed; If P_curr > P_set + ΔP, it is determined that there is a tendency of crystal blockage in the current discharge pipeline, the opening of the upward-opening automatic discharging valve is intervened to be adjusted, the step of generating a discharge control amount based on the liquid level parameter is paused, and an anti-blocking opening increment is generated according to the deviation degree between P_curr and P_set + ΔP, and the anti-blocking opening increment is added to the current opening value and then executed.

9. A method for preventing blockage of the discharge pipeline of a crystallizer as described in claim 8, characterized in that, When intervening to adjust the opening of the upward-opening automatic discharging valve, setting the pressure anti-blocking control priority to be higher than the liquid level control priority includes: Setting a pressure anti-blocking status flag, the pressure anti-blocking status flag includes an effective state and an invalid state, and the initial state is the invalid state; Before the step of generating a discharge control amount based on the liquid level parameter is executed, the pressure anti-blocking status flag is read; If the pressure anti-blocking status flag is in the invalid state, the step of generating a discharge control amount based on the liquid level parameter continues to be executed, and the generated discharge control amount is transmitted to the actuator of the upward-opening automatic discharging valve; If the pressure anti-blocking status flag is in the effective state, the step of generating a discharge control amount based on the liquid level parameter is paused, the current opening of the upward-opening automatic discharging valve is maintained unchanged, and the liquid level control is resumed after waiting for the pressure anti-blocking status flag to return to the invalid state.

10. A method for preventing blockage of the discharge pipeline of a crystallizer as described in claim 9, characterized in that, When intervening to adjust the opening of the upward-opening automatic discharging valve, setting the pressure anti-blocking control priority to be higher than the liquid level control priority further includes: When comparing the collected pressure parameter of the discharge pipeline with the preset pressure threshold, if the pressure parameter exceeds the preset pressure threshold, it is determined that there is a tendency of crystal blockage at the valve, the pressure anti-blocking status flag is set to the effective state, and the opening of the upward-opening automatic discharging valve is intervened to be adjusted; After intervening to adjust the opening of the upward-opening automatic discharging valve, the pressure parameter of the discharge pipeline is collected in real time, and the pressure parameter is continuously compared with the preset pressure threshold; When the pressure parameter returns to the range of the preset pressure threshold, it is determined that the tendency of crystal blockage has been eliminated, the pressure anti-blocking status flag is set to the invalid state, and the step of generating a discharge control amount based on the liquid level parameter is resumed; When resuming the liquid level control, a discharge control amount is regenerated according to the comparison result between the current liquid level parameter inside the crystallizer and the preset liquid level control threshold, and the discharge control amount is transmitted to the actuator of the upward-opening automatic discharging valve to adjust the valve opening to the state required for liquid level control.

11. A method for preventing blockage of the discharge pipeline of a crystallizer as described in claim 10, characterized in that, When the small stirring blade operates according to the determined operating parameters, it includes: Setting a small stirring blade operating status flag, the small stirring blade operating status flag includes an operating state and a stop state, and the initial state is the stop state; In the preset accumulation judgment threshold comparison step, if the detection parameter is greater than the preset accumulation judgment threshold, it is determined that there is crystalline material accumulation at the bottom of the cone. Before sending the control command to the drive mechanism of the small stirring blade, the running status flag of the small stirring blade is set to the running status. A control command is sent to the drive mechanism of the small stirring blade to control the small stirring blade to start running according to the determined operating parameters, including stirring speed, single operation duration and start-stop cycle; During the operation of the small agitator blades, before the controller performs the step of comparing the discharge pipeline pressure parameters with the preset pressure threshold, it first reads the small agitator blades' operating status flag bit. If the small agitator blade's operating status flag is in the operating state, the pressure anti-blockage opening adjustment action will be paused, and the current opening of the upward-expanding automatic discharge valve will remain unchanged. The controller will continuously collect the discharge pipeline pressure parameters and perform threshold comparison and judgment normally, cache and record abnormal events of pressure exceeding the threshold, and continuously monitor the small agitator blade's operating status flag.

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