Method and system for adaptive control of hollow fiber membrane cleaning pressure

Abstract

The application provides a hollow fiber membrane cleaning pressure self-adaptive adjustment control method and system, relates to the technical field of control, and comprises the following steps: determining a target transmembrane pressure difference interval by flushing an inlet water side and a water production side in a set temperature range; according to a transmembrane pressure difference deviation and a change rate, the inlet water pump rotating speed and the concentrated water discharge valve opening degree are cooperatively regulated in sequence of valve first and pump second; when the transmembrane pressure difference reaches the upper limit and the pollution is reversible, an impact cleaning sequence is generated, the concentrated water valve opening degree is increased, and the inlet water pump rotating speed is increased to form shearing scouring. The application realizes self-adaptive adjustment of the cleaning pressure in the membrane pollution process, and improves the membrane cleaning efficiency.

Description

Technical Field

[0001] This invention relates to the field of control technology, and in particular to a method and system for adaptive adjustment and control of hollow fiber membrane cleaning pressure. Background Technology

[0002] Hollow fiber membranes are crucial separation devices in water treatment, widely used in drinking water purification, wastewater treatment, and industrial separation. During long-term operation, impurities easily adhere to the membrane surface, forming a fouling layer. This leads to increased transmembrane pressure differential and decreased flux, ultimately affecting system treatment efficiency and membrane module lifespan. Therefore, regular cleaning and maintenance of the membrane is essential for ensuring stable system operation.

[0003] Traditional hollow fiber membrane cleaning technologies primarily employ fixed-parameter modes, meaning cleaning operations are performed according to preset time intervals, pressure, or flow parameters. This approach typically controls the cleaning process using constant pressure or constant flow modes, with operators setting cleaning parameters based on experience, lacking the ability to respond in real-time to the actual state of membrane fouling. Summary of the Invention

[0004] The present invention provides a method and system for adaptive adjustment and control of hollow fiber membrane cleaning pressure, which can solve the problems in the prior art.

[0005] A first aspect of the present invention provides a method for adaptive adjustment and control of hollow fiber membrane cleaning pressure, comprising:

[0006] Under the condition that the temperature of the cleaning solution is within the set range, the inlet side and the product water side are flushed at a constant flow rate. The pressure at the inlet end, the pressure at the outlet end, the transmembrane pressure difference and the instantaneous flow rate are recorded. The initial center value and allowable fluctuation band of the target transmembrane pressure difference range are calculated.

[0007] Using the initial center value of the target transmembrane pressure difference range as a reference, and combining the deviation and the rate of change of the transmembrane pressure difference, a coordinated control command is generated for the adjustment of the feed pump speed and the adjustment of the concentrate discharge valve opening. The control strategy allocates the adjustment amount in the order of valve first and then pump.

[0008] When the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible, a target flow velocity impact cleaning sequence is generated. The target flow velocity impact cleaning sequence increases the opening of the concentrate discharge valve according to a preset step size and simultaneously increases the speed of the influent pump to form shear scouring.

[0009] The influent and product water sides were flushed at a constant flow rate, and the influent pressure, effluent pressure, transmembrane pressure difference, and instantaneous flow rate were recorded. The initial center value and allowable fluctuation band of the target transmembrane pressure difference range were calculated, including:

[0010] During the constant flow setting phase, the constant flow rate on the inlet side is operated until the relative standard deviation of the instantaneous flow rate within the continuous sampling period is not greater than the preset deviation threshold, and the pressure change rate at the inlet end is less than the first preset change threshold, at which point the first set of data is recorded.

[0011] When the water production side is operated at a constant flow rate and the rate of change of the outlet pressure is less than the second preset change threshold during the continuous sampling period, and the first-order difference of the transmembrane pressure difference satisfies the stability judgment, the second set of data is recorded.

[0012] The median of the first and second sets of data after outlier removal is used as the initial center value of the target transmembrane pressure difference range, and the allowable fluctuation band is determined by the weighted value after normalization of the median and the measurement noise estimate.

[0013] Using the initial center value of the target transmembrane pressure differential range as a reference, and combining the deviation and rate of change of the transmembrane pressure differential, a coordinated control command is generated for the adjustment of the feed pump speed and the adjustment of the concentrate discharge valve opening. The control strategy allocates the adjustment amount in the order of valve first and then pump, including:

[0014] Based on the deviation of the transmembrane pressure difference from the initial center value of the target transmembrane pressure difference range and the rate of change of the deviation, a stratified decision is made. If the absolute value of the deviation is lower than the preset deviation threshold and the rate of change of the deviation is lower than the preset rate of change threshold, then only the opening of the concentrate discharge valve is adjusted in one direction.

[0015] When the absolute value of the deviation is higher than the preset deviation threshold or the deviation change rate is higher than the preset change rate threshold, the adjustment amount is allocated in the order of valve first and then pump: first, the opening of the concentrate discharge valve is adjusted according to the preset step size, and then when the opening of the concentrate discharge valve reaches the preset limit or the deviation does not fall back to within the threshold for two consecutive sampling cycles, the speed of the inlet pump is adjusted incrementally.

[0016] Independent rate-of-change constraints and minimum discernible step constraints are applied to the adjustment of the concentrate discharge valve opening and the inlet pump speed, respectively, and the rate-of-change constraints are automatically tightened when reverse continuous overshoot occurs. At the same time, the same-direction or opposite-direction cooperative relationship between the valve and the pump is determined by the combination of the sign of the transmembrane pressure difference deviation and the sign of the deviation rate of change. When the two signs are consistent, unidirectional coupling gain is executed, and when the two signs are opposite, decoupling and gain reduction are executed and the integral accumulation time of the next cycle is extended.

[0017] When the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible, the target flow velocity impact cleaning sequence is generated, including:

[0018] An upper limit contact indication function is established based on the upper limit of the target transmembrane pressure difference range, and the contact ratio and the average duration of continuous contact within the sliding time window of the upper limit contact indication function are used as upper limit contact characteristics.

[0019] The equivalent transmembrane pressure difference is calculated based on the inlet and outlet pressures. The consistency deviation between the equivalent transmembrane pressure difference and the sensor reading is used as the measurement consistency constraint. The reversible fouling indicator is constructed by the response elasticity between the combined adjustment of the inlet pump speed and the opening of the concentrate discharge valve and the cleaning flow rate.

[0020] When the upper limit touch feature meets the preset frequency and continuity requirements within the same sliding time window, and the reversible contamination indicator is reversible, while the consistency deviation is within the allowable range of the equipment calibration, a target flow rate impact cleaning sequence is generated.

[0021] Using the consistency deviation between the equivalent transmembrane pressure difference and the sensor reading as a measurement consistency constraint, and constructing a reversible fouling indication quantity based on the responsive elasticity between the combined adjustment of the influent pump speed and the concentrate discharge valve opening and the cleaning flow rate, the following are included:

[0022] The equivalent transmembrane pressure difference is calculated based on the pressure at the inlet and outlet ends, and a consistency deviation is constructed based on the difference between the equivalent transmembrane pressure difference and the transmembrane pressure difference sensor reading. The consistency deviation is used as a measurement consistency constraint to characterize the reliability of the pressure measurement.

[0023] Under the condition of meeting the measurement consistency constraint, the state vector of the actuator end composed of the inlet pump speed and the opening of the concentrate discharge valve is obtained, a synthetic adjustment quantity for the actuator end is formed, and the synthetic adjustment quantity is responded to by the real-time change of the cleaning flow rate to obtain the response elasticity reflecting the relationship between the actuator end input and the cleaning flow rate output.

[0024] A reversible contamination indicator is constructed based on the aforementioned response elasticity. When the synthetic adjustment amount increases and the consistency deviation is less than a preset deviation threshold, the contamination state is determined to be reversible contamination.

[0025] Increasing the opening of the concentrate discharge valve according to a preset step size and simultaneously increasing the speed of the inlet pump to form a shearing scouring process includes:

[0026] A planned trajectory for the target cleaning flow rate is constructed. The planned trajectory increases segment by segment according to a preset step size strategy and is constrained by the maximum allowable transmembrane pressure difference. The target cleaning flow rate increment is obtained in each control interval, and the execution end allocation requirement is formed accordingly.

[0027] The execution end allocation demand is coordinated in the order of valve first and then pump, and the opening degree of the concentrate discharge valve is preferentially advanced to establish a shear flow state.

[0028] When the direction of deviation change is consistent with the direction of transmembrane pressure difference change, coupling gain is used; when reverse overshoot occurs or the maximum permissible transmembrane pressure difference safety buffer zone is reached, decoupling gain is used.

[0029] The method further includes:

[0030] When the target cleaning flow rate reaches the planned trajectory and the transmembrane pressure difference is maintained within the target transmembrane pressure difference range, the impact maintenance phase begins. If the transmembrane pressure difference is lower than the lower limit of the target transmembrane pressure difference range during the impact maintenance phase, the impact cleaning is smoothly exited in reverse order of pump first and valve second, and the process returns to normal cleaning.

[0031] A second aspect of the present invention provides a hollow fiber membrane cleaning pressure adaptive adjustment control system, comprising:

[0032] The first unit is used to flush the inlet and product water sides at a constant flow rate under the condition that the temperature of the cleaning fluid is within a set range, record the inlet pressure, outlet pressure, transmembrane pressure difference and instantaneous flow rate, and calculate the initial center value and allowable fluctuation band of the target transmembrane pressure difference range.

[0033] The second unit is used to generate coordinated control commands for adjusting the speed of the feed pump and the opening of the concentrate discharge valve, taking the initial center value of the target transmembrane pressure difference range as a reference and combining the deviation and the rate of change of the transmembrane pressure difference. The control strategy allocates the adjustment amount in the order of valve first and then pump.

[0034] The third unit is used to generate a target flow velocity impact cleaning sequence when the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible. The target flow velocity impact cleaning sequence increases the opening of the concentrate discharge valve and simultaneously increases the speed of the influent pump to form shear scouring according to a preset step size.

[0035] A third aspect of the present invention,

[0036] An electronic device is provided, comprising:

[0037] processor;

[0038] Memory used to store processor-executable instructions;

[0039] The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0040] Fourth aspect of the present invention,

[0041] A computer-readable storage medium is provided, having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0042] The beneficial effects of this application are as follows:

[0043] By measuring the pressure parameters of the membrane module under constant flow, the target transmembrane pressure difference range and its fluctuation band are scientifically established, providing an accurate reference benchmark for the subsequent cleaning process and making the cleaning process more precise and controllable.

[0044] By adopting a collaborative control strategy based on transmembrane pressure difference deviation and rate of change, and optimizing the allocation of control commands by adjusting the valve first and then the pump, a smooth transition and precise adjustment of pressure during the cleaning process were achieved, which improved cleaning efficiency and reduced energy consumption.

[0045] When membrane fouling is detected to be reversible, a target flow rate impact cleaning sequence is automatically triggered. By coordinating the increase of the concentrate discharge valve opening and the increase of the feed pump speed, an effective shearing and scouring force is generated, which significantly enhances the ability to remove contaminants from the membrane surface and extends the service life of the membrane module. Attached Figure Description

[0046] Figure 1 This is a schematic flowchart of the adaptive adjustment and control method for hollow fiber membrane cleaning pressure in an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0049] Figure 1 This is a schematic flowchart of the adaptive adjustment and control method for hollow fiber membrane cleaning pressure in an embodiment of the present invention, as shown below. Figure 1 As shown, the method includes:

[0050] Under the condition that the temperature of the cleaning solution is within the set range, the inlet side and the product water side are flushed at a constant flow rate. The pressure at the inlet end, the pressure at the outlet end, the transmembrane pressure difference and the instantaneous flow rate are recorded. The initial center value and allowable fluctuation band of the target transmembrane pressure difference range are calculated.

[0051] Using the initial center value of the target transmembrane pressure difference range as a reference, and combining the deviation and the rate of change of the transmembrane pressure difference, a coordinated control command is generated for the adjustment of the feed pump speed and the adjustment of the concentrate discharge valve opening. The control strategy allocates the adjustment amount in the order of valve first and then pump.

[0052] When the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible, a target flow velocity impact cleaning sequence is generated. The target flow velocity impact cleaning sequence increases the opening of the concentrate discharge valve according to a preset step size and simultaneously increases the speed of the influent pump to form shear scouring.

[0053] In one optional implementation, the influent side and the product water side are flushed at a constant flow rate, and the influent pressure, effluent pressure, transmembrane pressure difference, and instantaneous flow rate are recorded. The initial center value and allowable fluctuation band of the target transmembrane pressure difference range are calculated, including:

[0054] During the constant flow setting phase, the constant flow rate on the inlet side is operated until the relative standard deviation of the instantaneous flow rate within the continuous sampling period is not greater than the preset deviation threshold, and the pressure change rate at the inlet end is less than the first preset change threshold, at which point the first set of data is recorded.

[0055] When the water production side is operated at a constant flow rate and the rate of change of the outlet pressure is less than the second preset change threshold during the continuous sampling period, and the first-order difference of the transmembrane pressure difference satisfies the stability judgment, the second set of data is recorded.

[0056] The median of the first and second sets of data after outlier removal is used as the initial center value of the target transmembrane pressure difference range, and the allowable fluctuation band is determined by the weighted value after normalization of the median and the measurement noise estimate.

[0057] In this embodiment, the membrane module transmembrane pressure differential control system includes a membrane module, a feed water pump, a product water pump, a feed water pressure sensor, an outlet water pressure sensor, a flow meter, and a control unit. The control unit is used to collect data, process data, and control the operation of the pumps. The membrane module can be a flat sheet membrane, a hollow fiber membrane, or a spiral wound membrane, etc., and is suitable for water treatment, gas separation, and other fields.

[0058] Before the flushing process begins, the data sampling period is set to 30 seconds, the preset deviation threshold is 2%, the first preset change threshold is 0.05 bar / min, and the second preset change threshold is 0.03 bar / min. The control unit starts the inlet pump and sets a constant inlet flow rate of 50 L / h to flush the inlet side of the membrane module. During this process, the inlet flow rate of the membrane module is monitored in real time by a flow meter, and data is recorded every 5 seconds. When the relative standard deviation of the 6 flow data points recorded within 30 consecutive seconds is 1.8%, which is less than the preset 2% threshold, and at the same time the inlet pressure change rate is 0.04 bar / min, which is less than the first preset change threshold of 0.05 bar / min, the system determines that the inlet side flushing has reached a stable state.

[0059] Under this stable condition, the first set of data is recorded, including inlet pressure, outlet pressure, transmembrane pressure difference, and instantaneous flow rate.

[0060] After the inlet side flushing is completed, the control unit shuts off the inlet pump and starts the product water pump, setting a constant product water flow rate of 50 L / h to flush the product water side of the membrane module. When the outlet pressure change rate is 0.02 bar / min for 30 consecutive seconds, which is less than the second preset change threshold of 0.03 bar / min, and the first-order difference calculation result of the transmembrane pressure difference is less than 0.01 bar for 3 consecutive times, the stability judgment condition is met, and the product water side flushing is determined to have reached a stable state.

[0061] Under stable conditions during permeate flushing, a second set of data was recorded. After acquiring both sets of data, the system performed outlier removal. Outlier removal employed a box plot method, setting the outlier criterion to 1.5 times the interquartile range. The average absolute value of the medians of the two sets of data was taken as the initial center value of the target transmembrane pressure differential range.

[0062] To determine the allowable fluctuation band and estimate the measurement noise, an estimate of the measurement noise is obtained by analyzing continuous measurement data under steady-state conditions. A normalization weighting factor is set according to the stability requirements of the application scenario. The allowable fluctuation band is obtained by weighting the median and the estimated measurement noise after normalization.

[0063] During actual operation, the control unit will adjust the operating parameters of the influent pump and the product pump according to this range to ensure that the transmembrane pressure difference is maintained within the set range.

[0064] In practical applications, the characteristics of different membrane modules with different materials and structures can be adapted by adjusting parameters such as the sampling period and preset threshold. For example, for polysulfone hollow fiber membranes, the sampling period can be shortened to 15 seconds and the preset deviation threshold can be adjusted to 1.5%; for polyamide composite membranes, the sampling period can be extended to 45 seconds and the preset deviation threshold can be adjusted to 2.5%.

[0065] The transmembrane pressure differential control range determined by the above method can effectively reduce membrane fouling and concentration polarization, extend the service life of membrane modules, improve system operating efficiency, and is suitable for precise control of various membrane separation processes.

[0066] In one optional implementation, using the initial center value of the target transmembrane pressure differential range as a reference, and combining the deviation and rate of change of the transmembrane pressure differential, a coordinated control command is generated for the adjustment of the feed pump speed and the adjustment of the concentrate discharge valve opening. The control strategy allocates the adjustment amount according to the order of valve first and then pump, including:

[0067] Based on the deviation of the transmembrane pressure difference from the initial center value of the target transmembrane pressure difference range and the rate of change of the deviation, a stratified decision is made. If the absolute value of the deviation is lower than the preset deviation threshold and the rate of change of the deviation is lower than the preset rate of change threshold, then only the opening of the concentrate discharge valve is adjusted in one direction.

[0068] When the absolute value of the deviation is higher than the preset deviation threshold or the deviation change rate is higher than the preset change rate threshold, the adjustment amount is allocated in the order of valve first and then pump: first, the opening of the concentrate discharge valve is adjusted according to the preset step size, and then when the opening of the concentrate discharge valve reaches the preset limit or the deviation does not fall back to within the threshold for two consecutive sampling cycles, the speed of the inlet pump is adjusted incrementally.

[0069] Independent rate-of-change constraints and minimum discernible step constraints are applied to the adjustment of the concentrate discharge valve opening and the inlet pump speed, respectively, and the rate-of-change constraints are automatically tightened when reverse continuous overshoot occurs. At the same time, the same-direction or opposite-direction cooperative relationship between the valve and the pump is determined by the combination of the sign of the transmembrane pressure difference deviation and the sign of the deviation rate of change. When the two signs are consistent, unidirectional coupling gain is executed, and when the two signs are opposite, decoupling and gain reduction are executed and the integral accumulation time of the next cycle is extended.

[0070] Before controlling the membrane system, a target transmembrane pressure differential range is first set, for example, 0.8-1.2 bar, with an initial center value of 1.0 bar. Simultaneously, a preset deviation threshold of 0.15 bar and a preset rate of change threshold of 0.05 bar / min are established. The current transmembrane pressure differential value is sampled every 30 seconds, and its deviation from the target center value and the rate of change of the deviation are calculated.

[0071] A hierarchical decision-making mechanism is employed for control. When the absolute value of the transmembrane pressure differential deviation is detected to be less than 0.15 bar and the rate of change of the deviation is less than 0.05 bar / min, only the opening of the concentrate discharge valve is adjusted unidirectionally. For example, if the current transmembrane pressure differential is 1.1 bar, the deviation is 0.1 bar, and the rate of change is 0.03 bar / min, the opening of the concentrate discharge valve is increased by 2% to reduce the transmembrane pressure differential. Conversely, if the transmembrane pressure differential is 0.92 bar, the deviation is -0.08 bar, and the rate of change is -0.02 bar / min, the opening of the concentrate discharge valve is decreased by 1% to increase the transmembrane pressure differential.

[0072] When the absolute value of the transmembrane pressure difference deviation exceeds 0.15 bar or the rate of change of deviation exceeds 0.05 bar / min, a valve-first, pump-later adjustment strategy is initiated. For example, in a specific scenario: the current transmembrane pressure difference is 1.35 bar, the deviation is 0.35 bar, and the rate of change is 0.08 bar / min, all exceeding preset thresholds. First, the opening of the concentrate discharge valve is adjusted by a preset step size of 5%, increasing it from 45% to 50%. If, in the next sampling cycle (30 seconds later), the transmembrane pressure difference is still 1.28 bar and the deviation is 0.28 bar, still exceeding the deviation threshold, the opening of the concentrate discharge valve is further increased to 55%. If, after two consecutive sampling cycles, the transmembrane pressure difference still does not fall below the threshold, or the opening of the concentrate discharge valve has reached the preset upper limit of 75%, the feed pump speed will be adjusted, for example, decreasing it from 85% to 82%.

[0073] For adjusting the opening of the concentrate discharge valve, the rate of change constraint is set to no more than ±8% per adjustment, and the minimum discernible step size is 1%. For adjusting the speed of the influent pump, the rate of change constraint is set to no more than ±5% per adjustment, and the minimum discernible step size is 0.5%. For example, if the calculation shows that the opening of the concentrate discharge valve needs to be adjusted by 10%, since it exceeds the rate of change constraint of 8%, the actual execution will be limited to 8%.

[0074] When a reverse continuous overshoot is detected, the rate of change constraint will be automatically tightened. For example, if the opening of the concentrate discharge valve increases, then decreases, and then increases again within three consecutive sampling periods, it indicates that there is a reverse continuous overshoot. The rate of change constraint of the concentrate discharge valve will be tightened from ±8% to ±5% to improve system stability.

[0075] The sign of the transmembrane pressure difference deviation and the sign of the rate of change of the deviation determine the coordination relationship between the valve and the pump. When the signs of the two are the same, such as a deviation of +0.25 bar and a rate of change of +0.06 bar / min, it indicates that the deviation is increasing, and the system executes a unidirectional coupling gain strategy. The opening step of the concentrate discharge valve increases from 5% to 6.5%, and the decrease step of the feed pump speed increases from 3% to 3.9%.

[0076] When the sign of the deviation is opposite to the sign of the rate of change, such as a deviation of +0.20 bar but a rate of change of -0.04 bar / min, it indicates that the deviation is decreasing on its own. The system executes a decoupling and gain reduction strategy, reducing the step size of the concentrate discharge valve opening from 5% to 3%, and the step size of the influent pump speed reduction from 3% to 1.8%. At the same time, the integral accumulation time of the next cycle is extended from 30 seconds to 45 seconds, giving the system more time to recover on its own.

[0077] Through actual testing, the membrane system using this collaborative control strategy reduced transmembrane pressure differential fluctuations by 42%, system energy consumption by 7.5%, and membrane fouling rate by 15% when facing fluctuations in influent water quality, while also significantly extending the membrane cleaning cycle. Particularly under high turbidity water conditions, this strategy can restore the transmembrane pressure differential to the target range much faster than traditional PID control, shortening the average recovery time by 58%, from 4.5 minutes to 1.9 minutes.

[0078] The core advantage of this control method lies in its precise control of the membrane system through a valve-first, pump-later distribution adjustment strategy, combined with dual judgments of deviation and deviation change rate, effectively avoiding the oscillation and over-adjustment problems in traditional control methods.

[0079] In one optional implementation, when the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the contamination is determined to be reversible, the generation of the target flow velocity impact cleaning sequence includes:

[0080] An upper limit contact indication function is established based on the upper limit of the target transmembrane pressure difference range, and the contact ratio and the average duration of continuous contact within the sliding time window of the upper limit contact indication function are used as upper limit contact characteristics.

[0081] The equivalent transmembrane pressure difference is calculated based on the inlet and outlet pressures. The consistency deviation between the equivalent transmembrane pressure difference and the sensor reading is used as the measurement consistency constraint. The reversible fouling indicator is constructed by the response elasticity between the combined adjustment of the inlet pump speed and the opening of the concentrate discharge valve and the cleaning flow rate.

[0082] When the upper limit touch feature meets the preset frequency and continuity requirements within the same sliding time window, and the reversible contamination indicator is reversible, while the consistency deviation is within the allowable range of the equipment calibration, a target flow rate impact cleaning sequence is generated.

[0083] During the operation of a membrane filtration system, membrane fouling can lead to an increase in transmembrane pressure difference (TMP). When the fouling is reversible, a target flow rate shock cleaning sequence will be initiated to restore membrane performance.

[0084] First, the operating parameters of the membrane module are acquired, including key parameters such as inlet pressure, outlet pressure, feed pump speed, and concentrate discharge valve opening. This data is collected in real time by pressure sensors, flow meters, and controllers and stored in the system database. A target transmembrane pressure differential range is set according to the membrane design specifications. For example, for a certain type of ultrafiltration membrane module, the target transmembrane pressure differential range is set to 0.08 MPa to 0.12 MPa, with 0.12 MPa as the upper limit.

[0085] To monitor transmembrane pressure fluctuations, an upper limit reach indicator function is established based on the upper limit of the target transmembrane pressure range. This function determines at each sampling time whether the current transmembrane pressure has reached or exceeded the upper limit value. Specifically, if the transmembrane pressure TMP(t) at the current time t is greater than or equal to the upper limit value of 0.12 MPa, the upper limit reach indicator function value is 1; otherwise, it is 0.

[0086] A sliding time window technique is used to monitor the upper limit being reached. In practical applications, the sliding time window is set to 4 hours, sliding forward every 10 minutes. Within each sliding window, the upper limit reach ratio and the average duration of consecutive reaches are calculated. The upper limit reach ratio is the ratio of the number of sampling points reaching the upper limit to the total number of sampling points within the window; the average duration of consecutive reaches is the average duration of consecutive upper limit reaches within the window. For example, within a 4-hour window, there are 480 sampling points (sampling interval of 30 seconds), of which 72 sampling points reach the upper limit, and there are 9 consecutive reach events, with each event lasting an average of 8 sampling points. In this case, the upper limit reach ratio is 15%, and the average duration of consecutive reaches is 4 minutes.

[0087] Simultaneously, the equivalent transmembrane pressure difference is calculated based on the inlet and outlet pressures. This equivalent transmembrane pressure difference takes into account the internal hydraulic characteristics and pressure distribution of the membrane module. It is obtained by subtracting the outlet pressure from the inlet pressure and correcting for a preset mapping coefficient, which can be a random number between 0 and 1. This equivalent transmembrane pressure difference is then compared with the direct sensor readings to calculate the consistency deviation. Under normal operating conditions, this deviation should remain within the allowable range specified by the equipment, for example, ±3%. If the deviation exceeds this range, it may indicate a sensor malfunction or pipeline abnormality, in which case the system will suspend the shock cleaning decision.

[0088] Determining the reversibility of contamination is a crucial step in deciding on impact cleaning. A reversible contamination indicator is constructed based on the response elasticity between the combined adjustment of the influent pump speed and the concentrate discharge valve opening and the cleaning flow rate. Specifically, the rate of flow change corresponding to increases in pump speed and changes in valve opening during each flushing operation is recorded to establish a response elasticity library. Under the current conditions, the system undergoes small-scale trial adjustments (e.g., temporarily increasing the pump speed by 5% for 30 seconds) and the flow rate change response is observed. If the response elasticity is close to or above 80% of the historical normal value, it is considered reversible contamination; if the response elasticity drops significantly to below 50% of the historical normal value, it is considered irreversible contamination, requiring intensive measures such as chemical cleaning.

[0089] The impact cleaning decision comprehensively considers three conditions: upper limit reach characteristics, reversible contamination indication, and consistency deviation. Preset requirements for the frequency and duration of upper limit reach are established, such as an upper limit reach rate exceeding 12% and an average duration of consecutive reach exceeding 2 minutes within a 4-hour window. When these reach requirements are met, and the reversible contamination indication is reversible (response elasticity greater than 80% of historical normal values), and the consistency deviation is within the allowable range (±3%), the system generates a target flow rate impact cleaning sequence.

[0090] The target flow rate impact cleaning sequence consists of three key parameters: impact flow rate, impact duration, and number of impacts. These parameters are adaptively adjusted based on membrane characteristics and fouling levels. For example, for a certain ultrafiltration membrane system, the standard impact flow rate is set to 2.5 times the normal filtration flow rate (e.g., from 25 LMH to 62.5 LMH), the impact duration is 45 seconds, the number of impacts is 3, and the interval between adjacent impacts is 15 seconds. The system achieves the target impact flow rate by controlling the feed pump speed to increase to the target value (e.g., from 1800 RPM to 3200 RPM) and adjusting the concentrate discharge valve opening (e.g., from 35% to 70%).

[0091] In a real-world application case, after eight days of operation, the ultrafiltration system at a water treatment plant repeatedly triggered the upper limit of 0.12 MPa in transmembrane pressure fluctuations over a continuous six-hour period. System sliding window analysis showed that the upper limit was triggered 18% of the time within the most recent four-hour window, with an average duration of 3.2 minutes, meeting the preset frequency and continuity requirements. Response resilience testing indicated that the current value was 87% of the historical normal value, classifying it as reversible fouling. Simultaneously, the consistency deviation between the equivalent transmembrane pressure and the sensor reading was 2.1%, within the acceptable range. Based on this, the system generated and executed a target flow rate shock cleaning sequence, increasing the flow rate from 25 LMH to 62.5 LMH, maintaining it for 45 seconds, and repeating this three times. After cleaning, the transmembrane pressure recovered to 0.09 MPa, confirming the cleaning effectiveness.

[0092] This intelligent judgment mechanism based on multi-dimensional features can accurately identify the appropriate time for shock cleaning, avoiding over-cleaning that shortens membrane life and under-cleaning that exacerbates fouling, thereby achieving optimized maintenance of membrane system performance.

[0093] In one optional implementation, the consistency deviation between the equivalent transmembrane pressure difference and the sensor reading is used as a measurement consistency constraint, and the reversible fouling indication is constructed by the responsive elasticity between the combined adjustment of the influent pump speed and the concentrate discharge valve opening and the cleaning flow rate, including:

[0094] The equivalent transmembrane pressure difference is calculated based on the pressure at the inlet and outlet ends, and a consistency deviation is constructed based on the difference between the equivalent transmembrane pressure difference and the transmembrane pressure difference sensor reading. The consistency deviation is used as a measurement consistency constraint to characterize the reliability of the pressure measurement.

[0095] Under the condition of meeting the measurement consistency constraint, the state vector of the actuator end composed of the inlet pump speed and the opening of the concentrate discharge valve is obtained, a synthetic adjustment quantity for the actuator end is formed, and the synthetic adjustment quantity is responded to by the real-time change of the cleaning flow rate to obtain the response elasticity reflecting the relationship between the actuator end input and the cleaning flow rate output.

[0096] A reversible contamination indicator is constructed based on the aforementioned response elasticity. When the synthetic adjustment amount increases and the consistency deviation is less than a preset deviation threshold, the contamination state is determined to be reversible contamination.

[0097] During the operation of a reverse osmosis membrane system, pressure sensor data is collected at both the inlet and outlet ends of the membrane system. The equivalent transmembrane pressure difference is obtained by calculating the difference between the inlet and outlet pressures. This equivalent transmembrane pressure difference differs from the reading provided by the dedicated transmembrane pressure difference sensor installed in the system. This difference is defined as the consistency deviation, calculated by subtracting the absolute value of the transmembrane pressure difference sensor reading from the equivalent transmembrane pressure difference. For example, if the calculated equivalent transmembrane pressure difference is 2.1 MPa, while the transmembrane pressure difference sensor reading is 2.0 MPa, the consistency deviation is 0.1 MPa.

[0098] A consistency deviation threshold of 0.2 MPa is set. When the actual consistency deviation is less than this threshold, the pressure measurement data is considered reliable. This measurement consistency constraint provides a data reliability guarantee for subsequent contamination status assessment. Continuous monitoring of consistency deviation can also reflect whether the pressure sensor has malfunctioned or drifted. For example, when the consistency deviation suddenly increases to 0.3 MPa, the system will generate a warning message indicating a possible sensor malfunction.

[0099] To ensure the reliability of measurement data, the status parameters of the reverse osmosis membrane system control actuators are acquired in real time, including the feed pump speed and the concentrate discharge valve opening. The feed pump speed is typically expressed as a percentage, such as 75% of the rated speed; the concentrate discharge valve opening is also expressed as a percentage, such as 30% opening. These two parameters constitute the actuator state vector, used to characterize the current operating state.

[0100] To construct the composite regulation, weighting coefficients are assigned to the influent pump speed and the concentrate discharge valve opening. Assuming the influent pump speed has a weight of 0.7 and the concentrate discharge valve opening has a weight of 0.3, the composite regulation is calculated as the weighted sum of the two. For example, when the influent pump speed is 80% and the concentrate discharge valve opening is 40%, the composite regulation is 0.7 × 80% + 0.3 × 40% = 68%.

[0101] Simultaneously monitor real-time changes in the cleaning flow rate, which refers to the effective cleaning water flow rate through the membrane surface, measured in cubic meters per hour. Collect data pairs of synthetic control and corresponding cleaning flow rates over a period of time; for example, record 20 sets of data at 30-second intervals within 10 minutes. Based on this data, calculate the response elasticity, i.e., the degree to which the cleaning flow rate responds to changes in the synthetic control.

[0102] The response elasticity is calculated as the ratio of the change in cleaning flow rate to the change in the synthetic regulation rate. For example, when the synthetic regulation rate increases from 68% to 73% (an increase of 5 percentage points), and the cleaning flow rate increases from 12.5 cubic meters per hour to 14.0 cubic meters per hour (an increase of 1.5 cubic meters per hour), the response elasticity is 1.5 ÷ 5 = 0.3 cubic meters per hour per percentage point.

[0103] A reversible fouling indicator is constructed based on the response elasticity value. Under normal conditions, the response elasticity typically remains within a preset normal range, such as 0.25 to 0.35 cubic meters per hour per percentage point. When reversible fouling occurs, the response elasticity decreases but remains within a recoverable range, for example, dropping to 0.15 to 0.25 cubic meters per hour per percentage point. However, when irreversible fouling occurs, the response elasticity decreases significantly, falling below 0.15 cubic meters per hour per percentage point.

[0104] The pollution state is determined by setting a response elasticity threshold for reversible pollution (e.g., 0.15 cubic meters / hour / percentage point). When the response elasticity is higher than this threshold and the consistency deviation is less than a preset deviation threshold (0.2 MPa), the current pollution state is determined to be reversible pollution.

[0105] To enhance the accuracy of the assessment, the dynamic trend of response elasticity is also monitored. By calculating the difference in response elasticity across three consecutive measurements, the recovery capability of the response elasticity can be identified. For example, if the response elasticity gradually recovers from 0.18 to 0.22 and 0.26 cubic meters per hour per percentage point when the synthetic adjustment is increased by 5 percentage points, it indicates that membrane fouling has good reversibility.

[0106] Based on the aforementioned technical methods, when a response elasticity of 0.23 cubic meters per hour per percentage point is detected and a consistency deviation of 0.15 MPa is taken, the current state is determined to be reversible fouling, and appropriate cleaning measures are recommended, such as increasing the frequency of chemical cleaning or adjusting the cleaning agent formulation. This reversible fouling judgment method based on response elasticity can effectively guide the maintenance strategy of membrane systems, extend membrane lifespan, and optimize system operating efficiency.

[0107] In one optional implementation, increasing the opening of the concentrate discharge valve according to a preset step size and simultaneously increasing the speed of the inlet pump to form a shearing scouring includes:

[0108] A planned trajectory for the target cleaning flow rate is constructed. The planned trajectory increases segment by segment according to a preset step size strategy and is constrained by the maximum allowable transmembrane pressure difference. The target cleaning flow rate increment is obtained in each control interval, and the execution end allocation requirement is formed accordingly.

[0109] The execution end allocation demand is coordinated in the order of valve first and then pump, and the opening degree of the concentrate discharge valve is preferentially advanced to establish a shear flow state.

[0110] When the direction of deviation change is consistent with the direction of transmembrane pressure difference change, coupling gain is used; when reverse overshoot occurs or the maximum permissible transmembrane pressure difference safety buffer zone is reached, decoupling gain is used.

[0111] During the operation of a membrane system, when contaminants accumulate on the surface of the membrane module to a certain extent, cleaning is required to restore the membrane's filtration performance. This embodiment provides a method for increasing the opening of the concentrate discharge valve by a preset step size while simultaneously increasing the speed of the feed pump to create shear scouring.

[0112] A planned trajectory for the target cleaning flow rate is constructed, which increases segment by segment according to a preset step size strategy. In practical applications, the base cleaning flow rate can be set to 0.8 m / s, the maximum cleaning flow rate to 1.5 m / s, and the preset step size to increase by 0.1 m / s every 10 seconds. The increase of the planned trajectory is constrained by the maximum allowable transmembrane pressure difference. For example, for polysulfone membrane materials, the maximum allowable transmembrane pressure difference is 80 kPa, and a safety buffer zone of 70-80 kPa is set. Within a control interval of 5 seconds, the increment of the target cleaning flow rate is calculated by comparing the current actual cleaning flow rate with the target cleaning flow rate on the planned trajectory. Assuming the current actual cleaning flow rate is 0.9 m / s and the target cleaning flow rate on the planned trajectory is 1.0 m / s, then the increment of the target cleaning flow rate is 0.1 m / s.

[0113] Based on the target cleaning flow rate increment, the actuator allocation requirements are generated and distributed to the concentrate discharge valve and the inlet pump. The actuator allocation employs a coordinated allocation strategy of valve first, then pump, prioritizing the discrete stepping of the concentrate discharge valve opening to establish a shear flow regime. The concentration discharge valve's stepping opening can be set to 5% as a basic step size. When the target cleaning flow rate increment is 0.1 m / s, the required concentration discharge valve opening increment is first calculated, for example, increasing from the current 30% opening to 35%. If simply increasing the concentration discharge valve opening is insufficient to achieve the target cleaning flow rate increment, the remaining required flow rate increment is calculated. For example, increasing the concentration discharge valve opening from 30% to 35% only provides a flow rate increment of 0.06 m / s; the remaining 0.04 m / s flow rate increment needs to be achieved by increasing the inlet pump speed.

[0114] The intake pump speed is adjusted using a frequency converter. Assuming the current intake pump speed is 1200 rpm, it is calculated that to compensate for the remaining 0.04 m / s flow velocity increment, the speed needs to be increased to 1248 rpm. Adjusting the intake pump speed requires considering the pump's characteristic curve, generally using a quadratic function relationship for mapping, i.e., the speed increment is quadratically proportional to the flow rate increment.

[0115] During execution, changes in transmembrane pressure differential are monitored in real time. When the direction of deviation change is consistent with the direction of transmembrane pressure differential change, coupling gain is used for control. For example, when the target cleaning flow rate increases and the actual transmembrane pressure differential also increases, a coupling gain coefficient of 0.8 will be used. That is, if the calculation requires an increase of 48 rpm in pump speed, the actual increase during execution will only be 38.4 rpm (48 × 0.8) to avoid membrane damage caused by an excessively rapid increase in transmembrane pressure differential.

[0116] When reverse overshoot occurs or the flow rate falls within the safety buffer zone of the maximum permissible transmembrane pressure difference, decoupling gain is used for control. Reverse overshoot refers to the actual cleaning flow rate exceeding the target cleaning flow rate, for example, the target is 1.0 m / s but the actual flow rate reaches 1.05 m / s. In this case, if the transmembrane pressure difference is 65 kPa, which is below the lower limit of the safety buffer zone of 70 kPa, a decoupling gain of 1.2 is used. This means that the calculated reduction in pump speed by 24 rpm is actually implemented by a reduction of 28.8 rpm (24 × 1.2) to accelerate the flow rate reduction. If the transmembrane pressure difference is within the safety buffer zone, such as 75 kPa, a larger decoupling gain of 1.5 is used to reduce the pump speed and valve opening more quickly, ensuring that the maximum permissible transmembrane pressure difference limit is not exceeded.

[0117] At the end of each control cycle, parameters such as the current cleaning flow rate, transmembrane pressure difference, valve opening, and pump speed are recorded as initial conditions for the next control cycle. The entire shearing and flushing process continues until the preset maximum cleaning flow rate of 1.5 m / s is reached or maintained for a predetermined time (usually 30-60 seconds). Then, the cleaning flow rate is gradually reduced according to a similar step-size strategy to return to normal filtration.

[0118] In a specific implementation case, the initial concentrate discharge valve opening of an industrial wastewater treatment membrane system was 25%, the influent pump speed was 1150 rpm, the cleaning flow rate was 0.75 m / s, and the transmembrane pressure difference was 55 kPa. The target maximum cleaning flow rate was set at 1.5 m / s, the maximum allowable transmembrane pressure difference at 80 kPa, and the safety buffer zone at 70-80 kPa. The target cleaning flow rate was increased by 0.1 m / s every 10 seconds. After 7 control cycles, the cleaning flow rate reached 1.45 m / s, the concentrate discharge valve opening reached 55%, the influent pump speed reached 1450 rpm, and the transmembrane pressure difference was 74 kPa, within the safety buffer zone. Decoupling gain control was used to prevent further increases in the cleaning flow rate, maintaining the current state for flushing, effectively removing contaminants from the membrane surface and restoring membrane performance.

[0119] In one optional implementation, the method further includes:

[0120] When the target cleaning flow rate reaches the planned trajectory and the transmembrane pressure difference is maintained within the target transmembrane pressure difference range, the impact maintenance phase begins. If the transmembrane pressure difference is lower than the lower limit of the target transmembrane pressure difference range during the impact maintenance phase, the impact cleaning is smoothly exited in reverse order of pump first and valve second, and the process returns to normal cleaning.

[0121] When the target cleaning flow rate reaches the value according to the preset trajectory, and the transmembrane pressure difference remains stably within the preset target transmembrane pressure difference range, the system automatically enters the impact maintenance phase. This target transmembrane pressure difference range is typically set to 35-55 kPa. This range ensures effective removal of membrane contaminants while avoiding damage to the membrane material. In practical applications, this range can be adjusted appropriately according to different membrane materials and levels of fouling. For example, for hollow fiber membranes made of polysulfone, it can be set to 40-50 kPa.

[0122] During the impact maintenance phase, changes in transmembrane pressure differential are continuously monitored. A high-precision pressure sensor is used to collect pressure values ​​across the membrane in real time, with a sampling frequency of 100Hz to ensure that even minute pressure changes can be captured. When the transmembrane pressure differential is detected to be below the lower limit of the target range (e.g., below 35 kPa for 3 seconds), it is determined that the membrane contaminants have been largely removed or the impact cleaning effect has reached its optimal state. At this point, continuing high-intensity impact cleaning will no longer be efficient, and therefore the impact cleaning mode needs to be exited.

[0123] The exit strategy for impact cleaning employs a reverse-sequence smooth exit approach: pump first, then valve. This involves the following steps: First, the cleaning pump speed is gradually reduced from the high flow rate of impact cleaning (e.g., 1.2 m / s) to the normal cleaning flow rate (e.g., 0.6 m / s) at a deceleration rate of 0.05 m / s per second. While the pump speed is decreasing, the control system continuously monitors pressure changes in the fluid pipeline to ensure no water hammer effect occurs. When the cleaning pump flow rate drops to 110% of the normal cleaning flow rate (approximately 0.66 m / s), the second step begins: gradually adjusting the valve opening.

[0124] The valve adjustment employs a segmented control strategy: for ball valves, the valve is closed from fully open at an angular velocity of 15° per second to the opening required for regular cleaning (typically 60°); for butterfly valves, the valve opening is adjusted at a rate of 10% per second. During the adjustment process, the control system provides real-time feedback on the flow rate and pressure in the pipeline to fine-tune the valve opening rate, ensuring that system pressure fluctuations do not exceed 5 kPa.

[0125] A specific data example is as follows: In an ultrafiltration system treating oily wastewater, the initial transmembrane pressure differential of the membrane module was 65 kPa, indicating severe membrane fouling. After initiating the shock cleaning, the cleaning flow rate rapidly increased from 0.5 m / s to 1.3 m / s, and the transmembrane pressure differential subsequently rose to 48 kPa and stabilized within the 45-50 kPa range, at which point the system entered the shock maintenance phase. After maintaining this for 6 minutes, the transmembrane pressure differential began to gradually decrease. When it dropped to 34 kPa and remained there for 4 seconds, the system determined that the transmembrane pressure differential was below the lower limit of the target range (35 kPa) and began the exit procedure. The cleaning pump speed first smoothly decreased from 1.3 m / s to 0.7 m / s within 8 seconds. Subsequently, the system adjusted the opening of the inlet ball valve, gradually reducing it from 90° to 60°. The entire exit process took 15 seconds, and the system smoothly transitioned to the normal cleaning state, with the transmembrane pressure differential stabilizing at 32 kPa.

[0126] By analyzing the effectiveness data of three consecutive impact cleaning cycles, the system automatically optimizes the exit strategy parameters. If the transmembrane pressure differential recovers faster after three consecutive impact cleaning cycles, the system will automatically extend the duration of the next impact by 5-10% and lower the exit judgment threshold by 3 kPa to enhance the cleaning effect.

[0127] During the exit process, if the pipeline pressure fluctuation is detected to exceed the preset safety threshold (usually 10 kPa), the system will immediately activate the secondary deceleration strategy to reduce the flow rate change rate and valve adjustment rate by 50% to ensure equipment safety.

[0128] This method effectively solves the water hammer effect and membrane contaminant redeposition problems caused by sudden interruptions in traditional impact cleaning by precisely controlling the timing and process of the impact cleaning process, thus achieving a balance between cleaning efficiency and system stability. Experimental data show that after adopting this smooth exit strategy, system pressure fluctuations were reduced by 85%, membrane flux recovery rate increased by 12%, and cleaning cycle was extended by 25%, significantly improving the overall operating efficiency of the membrane separation system and the service life of the membrane modules.

[0129] The hollow fiber membrane cleaning pressure adaptive adjustment control system in this embodiment of the invention includes:

[0130] The first unit is used to flush the inlet and product water sides at a constant flow rate under the condition that the temperature of the cleaning fluid is within a set range, record the inlet pressure, outlet pressure, transmembrane pressure difference and instantaneous flow rate, and calculate the initial center value and allowable fluctuation band of the target transmembrane pressure difference range.

[0131] The second unit is used to generate coordinated control commands for adjusting the speed of the feed pump and the opening of the concentrate discharge valve, taking the initial center value of the target transmembrane pressure difference range as a reference and combining the deviation and the rate of change of the transmembrane pressure difference. The control strategy allocates the adjustment amount in the order of valve first and then pump.

[0132] The third unit is used to generate a target flow velocity impact cleaning sequence when the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible. The target flow velocity impact cleaning sequence increases the opening of the concentrate discharge valve and simultaneously increases the speed of the influent pump to form shear scouring according to a preset step size.

[0133] A third aspect of the present invention provides an electronic device, comprising:

[0134] processor;

[0135] Memory used to store processor-executable instructions;

[0136] The processor is configured to invoke instructions stored in the memory to execute the aforementioned method.

[0137] A fourth aspect of the present invention provides a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, implement the aforementioned method.

[0138] This invention can be a method, apparatus, system, and / or computer program product. The computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for performing various aspects of the invention.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for adaptive adjustment and control of cleaning pressure for hollow fiber membranes, characterized in that, include: Under the condition that the temperature of the cleaning solution is within the set range, the inlet side and the product water side are flushed at a constant flow rate. The pressure at the inlet end, the pressure at the outlet end, the transmembrane pressure difference and the instantaneous flow rate are recorded. The initial center value and allowable fluctuation band of the target transmembrane pressure difference range are calculated. Using the initial center value of the target transmembrane pressure difference range as a reference, and combining the deviation and the rate of change of the transmembrane pressure difference, a coordinated control command is generated for the adjustment of the feed pump speed and the adjustment of the concentrate discharge valve opening. The control strategy allocates the adjustment amount in the order of valve first and then pump. When the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible, a target flow velocity impact cleaning sequence is generated. The target flow velocity impact cleaning sequence increases the opening of the concentrate discharge valve according to a preset step size and simultaneously increases the speed of the influent pump to form shear scouring.

2. The method according to claim 1, characterized in that, The influent and product water sides were flushed at a constant flow rate, and the influent pressure, effluent pressure, transmembrane pressure difference, and instantaneous flow rate were recorded. The initial center value and allowable fluctuation band of the target transmembrane pressure difference range were calculated, including: During the constant flow setting phase, the constant flow rate on the inlet side is operated until the relative standard deviation of the instantaneous flow rate within the continuous sampling period is not greater than the preset deviation threshold, and the pressure change rate at the inlet end is less than the first preset change threshold, at which point the first set of data is recorded. When the water production side is operated at a constant flow rate and the rate of change of the outlet pressure is less than the second preset change threshold during the continuous sampling period, and the first-order difference of the transmembrane pressure difference satisfies the stability judgment, the second set of data is recorded. The median of the first and second sets of data after outlier removal is used as the initial center value of the target transmembrane pressure difference range, and the allowable fluctuation band is determined by the weighted value after normalization of the median and the measurement noise estimate.

3. The method according to claim 1, characterized in that, Using the initial center value of the target transmembrane pressure differential range as a reference, and combining the deviation and rate of change of the transmembrane pressure differential, a coordinated control command is generated for the adjustment of the feed pump speed and the adjustment of the concentrate discharge valve opening. The control strategy allocates the adjustment amount in the order of valve first and then pump, including: Based on the deviation of the transmembrane pressure difference from the initial center value of the target transmembrane pressure difference range and the rate of change of the deviation, a stratified decision is made. If the absolute value of the deviation is lower than the preset deviation threshold and the rate of change of the deviation is lower than the preset rate of change threshold, then only the opening of the concentrate discharge valve is adjusted in one direction. When the absolute value of the deviation is higher than the preset deviation threshold or the deviation change rate is higher than the preset change rate threshold, the adjustment amount is allocated in the order of valve first and then pump: first, the opening of the concentrate discharge valve is adjusted according to the preset step size, and then when the opening of the concentrate discharge valve reaches the preset limit or the deviation does not fall back to within the threshold for two consecutive sampling cycles, the speed of the inlet pump is adjusted incrementally. Independent rate-of-change constraints and minimum discernible step constraints are applied to the adjustment of the concentrate discharge valve opening and the inlet pump speed, respectively, and the rate-of-change constraints are automatically tightened when reverse continuous overshoot occurs. At the same time, the same-direction or opposite-direction cooperative relationship between the valve and the pump is determined by the combination of the sign of the transmembrane pressure difference deviation and the sign of the deviation rate of change. When the two signs are consistent, unidirectional coupling gain is executed, and when the two signs are opposite, decoupling and gain reduction are executed and the integral accumulation time of the next cycle is extended.

4. The method according to claim 1, characterized in that, When the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible, the target flow velocity impact cleaning sequence is generated, including: An upper limit contact indication function is established based on the upper limit of the target transmembrane pressure difference range, and the contact ratio and the average duration of continuous contact within the sliding time window of the upper limit contact indication function are used as upper limit contact characteristics. The equivalent transmembrane pressure difference is calculated based on the inlet and outlet pressures. The consistency deviation between the equivalent transmembrane pressure difference and the sensor reading is used as the measurement consistency constraint. The reversible fouling indicator is constructed by the response elasticity between the combined adjustment of the inlet pump speed and the opening of the concentrate discharge valve and the cleaning flow rate. When the upper limit touch feature meets the preset frequency and continuity requirements within the same sliding time window, and the reversible contamination indicator is reversible, while the consistency deviation is within the allowable range of the equipment calibration, a target flow rate impact cleaning sequence is generated.

5. The method according to claim 4, characterized in that, Using the consistency deviation between the equivalent transmembrane pressure difference and the sensor reading as a measurement consistency constraint, and constructing a reversible fouling indication quantity based on the responsive elasticity between the combined adjustment of the influent pump speed and the concentrate discharge valve opening and the cleaning flow rate, the following are included: The equivalent transmembrane pressure difference is calculated based on the pressure at the inlet and outlet ends, and a consistency deviation is constructed based on the difference between the equivalent transmembrane pressure difference and the transmembrane pressure difference sensor reading. The consistency deviation is used as a measurement consistency constraint to characterize the reliability of the pressure measurement. Under the condition of meeting the measurement consistency constraint, the state vector of the actuator end composed of the inlet pump speed and the opening of the concentrate discharge valve is obtained, a synthetic adjustment quantity for the actuator end is formed, and the synthetic adjustment quantity is responded to by the real-time change of the cleaning flow rate to obtain the response elasticity reflecting the relationship between the actuator end input and the cleaning flow rate output. A reversible contamination indicator is constructed based on the aforementioned response elasticity. When the synthetic adjustment amount increases and the consistency deviation is less than a preset deviation threshold, the contamination state is determined to be reversible contamination.

6. The method according to claim 1, characterized in that, Increasing the opening of the concentrate discharge valve according to a preset step size and simultaneously increasing the speed of the inlet pump to form a shearing scouring process includes: A planned trajectory for the target cleaning flow rate is constructed. The planned trajectory increases segment by segment according to a preset step size strategy and is constrained by the maximum allowable transmembrane pressure difference. The target cleaning flow rate increment is obtained in each control interval, and the execution end allocation requirement is formed accordingly. The execution end allocation demand is coordinated in the order of valve first and then pump, and the opening degree of the concentrate discharge valve is preferentially advanced to establish a shear flow state. When the direction of deviation change is consistent with the direction of transmembrane pressure difference change, coupling gain is used; when reverse overshoot occurs or the maximum permissible transmembrane pressure difference safety buffer zone is reached, decoupling gain is used.

7. The method according to claim 6, characterized in that, The method further includes: When the target cleaning flow rate reaches the planned trajectory and the transmembrane pressure difference is maintained within the target transmembrane pressure difference range, the impact maintenance phase begins. If the transmembrane pressure difference is lower than the lower limit of the target transmembrane pressure difference range during the impact maintenance phase, the impact cleaning is smoothly exited in reverse order of pump first and valve second, and the process returns to normal cleaning.

8. A hollow fiber membrane cleaning pressure adaptive adjustment control system, used to implement the method as described in any one of claims 1-7, characterized in that, include: The first unit is used to flush the inlet and product water sides at a constant flow rate under the condition that the temperature of the cleaning fluid is within a set range, record the inlet pressure, outlet pressure, transmembrane pressure difference and instantaneous flow rate, and calculate the initial center value and allowable fluctuation band of the target transmembrane pressure difference range. The second unit is used to generate coordinated control commands for adjusting the speed of the feed pump and the opening of the concentrate discharge valve, taking the initial center value of the target transmembrane pressure difference range as a reference and combining the deviation and the rate of change of the transmembrane pressure difference. The control strategy allocates the adjustment amount in the order of valve first and then pump. The third unit is used to generate a target flow velocity impact cleaning sequence when the transmembrane pressure difference fluctuation amplitude repeatedly touches the upper limit of the target transmembrane pressure difference range within the target time and the fouling is determined to be reversible. The target flow velocity impact cleaning sequence increases the opening of the concentrate discharge valve and simultaneously increases the speed of the influent pump to form shear scouring according to a preset step size.

9. An electronic device, characterized in that, include: processor; Memory used to store processor-executable instructions; The processor is configured to invoke instructions stored in the memory to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having computer program instructions stored thereon, characterized in that, When the computer program instructions are executed by the processor, they implement the method described in any one of claims 1 to 7.

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