Water treatment control system and method based on multi-membrane collaborative purification

Abstract

The invention discloses a water treatment control system and method based on multi-membrane collaborative purification, and belongs to the field of industrial control systems, and the system comprises the following modules: a water treatment control first path module, a multi-membrane state label determination module, and a water treatment control second path determination module. According to the water treatment control system and method based on multi-membrane collaborative purification, collaborative monitoring and dynamic adjustment of a front-stage membrane section and a rear-stage membrane section are achieved, the change of transmembrane pressure difference, effluent turbidity, outlet flow and membrane section loads can be responded in real time, and multi-membrane collaborative purification is achieved by adjusting the opening degree of a multi-membrane linkage valve and adjusting the frequency of a main pump. And flow balance, load optimization and water quality stability are realized.

Description

Technical Field

[0001] This invention relates to the field of industrial control system technology, and in particular to a water treatment control system and method based on multi-membrane synergistic purification. Background Technology

[0002] Existing multi-membrane synergistic water treatment control systems typically employ a combination of multi-stage membrane separation structures and automated control strategies to achieve step-by-step purification and efficient desalination of raw water. A typical structure includes microfiltration or ultrafiltration as a pretreatment unit to remove suspended solids, colloids, and large particulate impurities; and nanofiltration or reverse osmosis as a deep purification unit to remove dissolved salts and organic micropollutants.

[0003] For example, Chinese invention patent CN118295350B discloses an industrial equipment control system for water treatment, which includes: a parameter acquisition module, a parameter preprocessing module, a pressure monitoring module, a chance factor calculation module, a reverse osmosis membrane analysis module, a water purification performance evaluation module, an equipment control module, a cleaning judgment module, a cleaning control module, an alarm module, and an interaction center. By including a water purification performance evaluation module, it is beneficial to derive the positive compensation coefficient and the negative compensation coefficient of water purification cost based on the membrane performance index and the water purification cost data of the target object, and to evaluate the overall water purification performance of the target object to obtain the water purification performance evaluation coefficient. The equipment is intelligently controlled through data, and real-time warnings are given based on the evaluation results, so as to replace the reverse osmosis membrane in a timely manner.

[0004] For example, the water treatment control system and control device disclosed in Chinese invention patent CN115826506B includes: a monitoring system and a processing system, which has multiple processing modules. Each processing module is connected to a corresponding monitoring module for continuous comparison of the monitoring results obtained by the monitoring module to determine whether each monitoring result exceeds a set threshold. If the set threshold is not exceeded, the monitoring result and comparison result are stored. If at least one monitoring result exceeds the set threshold, it is input into a machine learning system. This application provides a method to independently monitor the equipment operating parameters, process parameters, and processing results of each process unit while analyzing whether the cause of the problem in the process unit is affected by the preceding / following process units. In this way, when adjusting, all affected processes can be adjusted, rather than adjusting only the problematic process in isolation.

[0005] The above-mentioned technology has at least the following technical problems: When the flow rate is too high, with fast water velocity and short residence time, the antifouling membrane cannot fully remove pollutants and salts, leading to an increase in the transmembrane pressure difference or conductivity of the seawater desalination membrane feed water. Conversely, when the flow rate is too low, the antifouling membrane may experience abnormal loading on the desalination membrane section, resulting in a decrease in desalination efficiency. Furthermore, excessively high loading or uneven pressure distribution on the antifouling membrane section can accelerate membrane pore blockage and fouling accumulation, further reducing the membrane's desalination capacity and causing deviations in effluent water quality. Summary of the Invention

[0006] On the one hand, a water treatment control system based on multi-membrane synergistic purification is provided, the system comprising: The first path module for water treatment control is used to collect the effluent parameters of the freshwater membrane string, thereby analyzing and determining the first path for water treatment control, and when the first path for water treatment control is the front-end regulation, to perform coordinated regulation of the freshwater membrane and the antifouling membrane.

[0007] The multi-membrane status label determination module is used to collect flow parameters of antifouling membranes, analyze the flow state index of antifouling membrane outlet water, determine the status label of antifouling membrane string, and simultaneously collect load parameters of seawater desalination membranes, analyze the membrane segment load of seawater desalination membranes, and determine the status label of seawater desalination membranes.

[0008] The water treatment control second path determination module is used to determine the water treatment control second path by combining the status tags of the antifouling membrane string and the seawater desalination membrane, and then execute it.

[0009] On the other hand, a water treatment control method based on multi-membrane synergistic purification is provided, the method comprising: The effluent parameters of the freshwater membrane string are collected, and the first water treatment control path is determined by analysis. When the first water treatment control path is the front-end regulation, the freshwater membrane and the antifouling membrane are synergistically regulated.

[0010] The flow parameters of the antifouling membrane were collected, the outlet flow state index of the antifouling membrane was analyzed, and the status label of the antifouling membrane string was determined. At the same time, the load parameters of the seawater desalination membrane were collected, the membrane segment load of the seawater desalination membrane was analyzed, and the status label of the seawater desalination membrane was determined.

[0011] The second path for water treatment control is determined by combining the status tags of the antifouling membrane string and the seawater desalination membrane, and then executed.

[0012] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: 1. This invention achieves coordinated monitoring and dynamic adjustment of upstream and downstream membrane stages by collecting key indicators such as freshwater membrane effluent turbidity, transmembrane pressure difference, antifouling membrane outlet flow state index, and seawater desalination membrane segment load. This enables fully automated control of the entire process of antifouling membrane, freshwater membrane, and seawater desalination membrane. The system can respond in real time to changes in transmembrane pressure difference, effluent turbidity, outlet flow rate, and membrane segment load. Through multi-mode linkage valve opening adjustment and main pump frequency adjustment, it achieves flow balance, load optimization, and water quality stability. At the same time, the system has a backup membrane string activation function, which can quickly divert flow and relieve pressure when the membrane segment is overloaded or the effluent is abnormal. It also extends membrane life through trend prediction and short-term membrane flushing, improving system safety, reliability, and high-efficiency operation.

[0013] 2. This invention collects the effluent turbidity and transmembrane pressure difference of the freshwater membrane string and compares them with the effluent turbidity threshold and transmembrane pressure difference threshold of the freshwater membrane to determine whether the membrane segment needs adjustment. When the effluent turbidity is high and the transmembrane pressure difference is normal, the system calculates the reduction value of the freshwater membrane valve opening based on the turbidity deviation, quickly responds to membrane segment abnormalities, prevents membrane surface fouling from aggravating or membrane load from being too high, and then determines the reduction value of the antifouling membrane valve opening according to the upstream linkage rules, and performs valve adjustment of both the freshwater membrane and the antifouling membrane to reduce the upstream flow rate. The upstream and downstream linkage ensures that the upstream flow rate matches the downstream seawater desalination membrane, ensuring membrane residence time and filtration effect, and avoiding insufficient upstream flushing or excessive flow rate.

[0014] 3. This invention collects the outlet flow state index of the antifouling membrane and the membrane segment load of the seawater desalination membrane, analyzes the outlet flow deviation and membrane segment load deviation, and corrects the flow through main pump regulation and valve fine-tuning when the outlet flow is higher than the threshold and the membrane segment load is normal. The coordinated regulation of the upstream and downstream membrane segments improves the system's adaptability under different load conditions. The short-term membrane flushing function effectively extends the membrane life, can alleviate local membrane segment overload, prevent membrane damage or effluent water quality degradation, and improve the long-term operational reliability of the system.

[0015] 4. This invention determines the influent flow rate by activating the backup membrane string and based on the deviation of the antifouling membrane outlet flow state index and the change in the seawater desalination membrane valve, thereby achieving load splitting and completing the joint fine-tuning of multiple membrane segments. This ensures the balance of flow and load between the upstream and downstream membrane segments, while the backup membrane splitting ensures the water production capacity under high load. The comprehensive adjustment improves the load adaptability of the membrane system, enabling safe operation even under high load conditions. The multi-membrane segment fine-tuning and backup membrane splitting avoid local overload and ensure stable effluent water quality. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a water treatment control system based on multi-membrane synergistic purification provided in an embodiment of the present invention; Figure 2 This is a flowchart of a water treatment control method based on multi-membrane synergistic purification provided by an embodiment of the present invention; Figure 3 This is a strategy diagram of a water treatment control method based on multi-membrane synergistic purification provided by an embodiment of the present invention; Figure 4 This is a mind map of a water treatment control system based on multi-membrane synergistic purification provided by an embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0019] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0020] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0021] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0022] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0023] like Figure 1The diagram shows a water treatment control system based on multi-membrane synergistic purification, which includes a first path module for water treatment control, a multi-membrane status label determination module, and a second path module for water treatment control.

[0024] The water treatment control first path module is used to collect the effluent parameters of the freshwater membrane string, thereby analyzing and determining the water treatment control first path, and when the water treatment control first path is the front-end regulation, to perform coordinated regulation of the freshwater membrane and the antifouling membrane.

[0025] The multi-membrane status label determination module is used to collect flow parameters of antifouling membranes, analyze the flow state index of antifouling membrane outlet water, determine the status label of antifouling membrane string, and simultaneously collect load parameters of seawater desalination membranes, analyze the membrane segment load of seawater desalination membranes, and determine the status label of seawater desalination membranes.

[0026] The water treatment control second path determination module is used to determine the water treatment control second path by combining the status tags of the antifouling membrane string and the seawater desalination membrane, and then execute it.

[0027] like Figure 3 This is a strategy diagram of a water treatment control method based on multi-membrane synergistic purification provided by an embodiment of the present invention. It collects the effluent turbidity and transmembrane pressure difference of the freshwater membrane to determine the first water treatment control path. Subsequently, it monitors the flow parameters of the antifouling membrane, analyzes the effluent flow state index of the antifouling membrane and the membrane segment load state of the seawater desalination membrane, and analyzes the status labels of the antifouling membrane string and the seawater desalination membrane. Based on this, it determines the second water treatment control path: according to different status label combinations, it is divided into the following three stages: subsequent multi-membrane synergistic first regulation, subsequent multi-membrane synergistic second regulation, and subsequent multi-membrane synergistic third regulation.

[0028] This system's multi-membrane module is divided into a front section, a middle section, and a back section. The front section is equipped with a freshwater membrane for preliminary filtration of suspended particles and large particulate impurities in the water, reducing the pollution load entering subsequent membrane sections and ensuring the overall water quality stability of the system. The middle section is equipped with an antifouling membrane, which enhances the interception and dispersion of flow load for easily fouling components such as colloids, microorganisms, and organic matter, reducing the risk of membrane fouling, while providing stable feed water conditions for the subsequent seawater desalination membrane. The back section uses a seawater desalination membrane to achieve high-salinity desalination and produce freshwater that meets design requirements.

[0029] It should be explained that the water treatment control system includes influent control equipment, segmented flow regulation equipment, and product water and concentrate flow regulation equipment.

[0030] The front-end freshwater membrane mainly corresponds to the inlet water control equipment, including the inlet valve. The inlet valve is installed on the inlet pipe of the freshwater membrane module and is used to regulate the total inlet water flow into the membrane section.

[0031] The mid-section antifouling membrane corresponds to a segmented flow control device, including segmented inlet valves for each membrane segment and an overall inlet valve for the entire device. The segmented valves are installed on the inlet branch pipes of each membrane segment and are used to finely adjust the flow rate ratio of each membrane segment.

[0032] The downstream seawater desalination membrane system includes equipment for regulating the flow rates of permeate and concentrate, comprising the inlet valve, permeate valve, concentrate valve, and necessary bypass valves. The permeate valve is installed on the permeate manifold of the membrane section and is used to regulate the permeate flow rate, controlling the membrane flux and desalination rate; the concentrate valve is installed on the concentrate outlet pipe and is used to regulate the concentrate discharge rate.

[0033] The following freshwater membrane valves refer to the inlet valves of the inlet water control equipment, antifouling membrane valves refer to the inlet valves of the segmented flow regulation equipment, and seawater desalination membrane valves refer to the inlet valves of the product water and concentrate flow regulation equipment.

[0034] The effluent parameters of the freshwater membrane string are collected, and the first water treatment control path is determined by analysis. When the first water treatment control path is the front-end regulation, the freshwater membrane and the antifouling membrane are synergistically regulated.

[0035] Furthermore, the first control path for water treatment was determined through analysis, and when the first control path for water treatment was the front-end regulation, the synergistic regulation of the freshwater membrane and the antifouling membrane was carried out. The specific analysis method is as follows: Within the preset monitoring period, the effluent turbidity and transmembrane pressure difference of the freshwater membrane string are collected.

[0036] Extract the effluent turbidity threshold and transmembrane pressure difference threshold of the pre-set freshwater membrane string from the database.

[0037] If the transmembrane pressure difference is greater than or equal to the transmembrane pressure difference threshold, the first path of water treatment control is determined to require no adjustment, and an alarm message is generated.

[0038] It should be explained that effluent turbidity refers to the degree to which suspended particles, colloids and fine impurities in the produced water affect the transparency of the water after membrane treatment. It is a key indicator reflecting the membrane filtration effect and the stability of the effluent water quality. It is collected by an online turbidity sensor on the produced water pipeline, and the turbidity change of the water sample is detected in real time using the principle of transmitted light. The collected turbidity signal is transmitted to the control system through a digital communication interface.

[0039] Transmembrane pressure difference refers to the difference between the pressure on the feed water side and the pressure on the product water side of the membrane. It is used to measure the driving force of the pressure difference across the membrane and the degree of membrane fouling. It is an important process parameter for assessing the membrane's operating status. By collecting pressure sensors on the feed water pipeline and product water pipeline of each membrane segment, the feed water pressure and product water pressure data are collected in real time, and the difference between the two is calculated to obtain the current transmembrane pressure difference.

[0040] It should be noted that if the transmembrane pressure difference is greater than or equal to the transmembrane pressure difference threshold, the membrane module's operating pressure is determined to have reached its safe upper limit. At this point, the system will set the first path for water treatment control to require no adjustment, meaning no further adjustments will be made to the influent flow rate, pump frequency, or valve opening, to avoid excessive pressure on the membrane surface, which could cause damage or accelerate fouling. Simultaneously, the system will automatically generate an alarm message, alerting operators that the membrane module may be at risk of increased fouling or abnormal pressure difference.

[0041] In this embodiment, the alarm message could be: "Attention! Abnormal transmembrane pressure difference in freshwater membrane." If the transmembrane pressure difference is less than the transmembrane pressure difference threshold and the effluent turbidity is greater than the effluent turbidity threshold, the first path of water treatment control is determined as the front-end regulation.

[0042] It should be noted that when the transmembrane pressure difference is less than the transmembrane pressure difference threshold and the effluent turbidity is greater than the effluent turbidity threshold, it indicates that the membrane module is not limited by the excessive pressure difference, but the effluent water quality has shown a deteriorating trend, which may be related to insufficient pretreatment of the freshwater membrane. At this time, the system determines the first path of water treatment control as front-end regulation, that is, by adjusting the flow distribution of the freshwater membrane, the antifouling membrane is linked to make corresponding adjustments.

[0043] If the transmembrane pressure difference is less than the transmembrane pressure difference threshold, and the effluent turbidity is less than or equal to the effluent turbidity threshold, the first path of water treatment control is determined to require no adjustment.

[0044] It should be noted that when the transmembrane pressure difference is less than the transmembrane pressure difference threshold, and the effluent turbidity is less than or equal to the effluent turbidity threshold, it indicates that the membrane module is operating well. There is no risk of excessive pressure on the membrane surface, nor is there any decline in effluent water quality. At this time, the system determines that the membrane is operating in a stable range and sets the first path of water treatment control to require no adjustment, maintaining the current operating parameters such as flow rate, pressure, and valve opening unchanged.

[0045] The deviation value of the effluent turbidity of the freshwater membrane is obtained by comparing the effluent turbidity with the effluent turbidity threshold.

[0046] It should be noted that the turbidity deviation value of the freshwater membrane effluent is obtained by subtracting the turbidity threshold from the turbidity of the freshwater membrane effluent.

[0047] The reduction value of the freshwater membrane valve opening is determined based on the turbidity deviation value of the freshwater membrane effluent, and the reduction value of the antifouling membrane valve opening is determined based on the reduction value of the freshwater membrane valve opening.

[0048] It should be noted that in this embodiment, the system pre-sets the correspondence rules between the turbidity deviation value of the freshwater membrane effluent and the reduction value of the freshwater membrane valve opening, and stores them in a configuration file or parameter table for unified invocation. During operation, the system first calculates the turbidity deviation value of the freshwater membrane effluent in real time to reflect the degree of deviation of the freshwater membrane effluent quality from the target threshold. According to the preset rules, the system can establish the correspondence between turbidity deviation and valve adjustment range through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching reduction value of the freshwater membrane valve opening. The core logic is that the larger the turbidity deviation value of the freshwater membrane effluent, the more obvious the fluctuation of the filtration effect of the freshwater membrane. If the valve opening is not reduced in time, it may lead to excessively fast water flow and insufficient pollutant interception. Therefore, the larger the turbidity deviation of the freshwater membrane effluent, the larger the absolute value of the corresponding reduction in the opening of the freshwater membrane valve should be, in order to enhance filtration stability. Subsequently, based on the calculated reduction in the opening of the freshwater membrane valve, the system determines the reduction in the opening of the antifouling membrane valve according to the preset linkage adjustment rules, thereby achieving coordinated adjustment of the upstream and downstream membrane stages and ensuring overall water quality stability and operational safety.

[0049] The opening of the freshwater membrane valve is adjusted based on the decrease in the opening value of the freshwater membrane valve, and the opening of the antifouling membrane valve is adjusted based on the decrease in the opening value of the antifouling membrane valve, thereby completing the front-end regulation.

[0050] It should be noted that the freshwater membrane valve opening update value is obtained by adding the freshwater membrane valve opening reduction value to the current freshwater membrane valve opening value, and the freshwater membrane valve is operated with the freshwater membrane valve opening update value. Similarly, the antifouling membrane valve opening update value is obtained by adding the antifouling membrane valve opening reduction value to the current antifouling membrane valve opening value, and the antifouling membrane valve is operated with the antifouling membrane valve opening update value. This coordinated regulation of the freshwater membrane and the antifouling membrane achieves front-end regulation.

[0051] The flow parameters of the antifouling membrane were collected, the outlet flow state index of the antifouling membrane was analyzed, and the status label of the antifouling membrane string was determined. At the same time, the load parameters of the seawater desalination membrane were collected, the membrane segment load of the seawater desalination membrane was analyzed, and the status label of the seawater desalination membrane was determined.

[0052] Furthermore, the flow state index of the antifouling membrane outlet water was analyzed, and the specific analysis method is as follows: Collect the outlet water flow parameters of the antifouling membrane, including outlet flow rate, outlet pressure, and product water conductivity.

[0053] It should be noted that the effluent flow rate is measured in real time by a turbine flow meter on the membrane module. The flow meter detects the induced signal from the water in a magnetic field or impeller rotation, converts it into a standard electrical signal, and then processes it through a signal conditioning module before inputting it to the control system. The control system collects flow rate data at a frequency of seconds or minutes and combines it with historical operating curves to determine changes in membrane flux and load distribution, providing a basis for flow regulation and membrane section load optimization.

[0054] The outlet water pressure is detected by high-precision pressure transmitters installed at the outlet of each membrane segment. The pressure changes are sensed by strain gauge or piezoresistive sensing elements, and the pressure signal is converted into a standard current signal. The system continuously collects this signal, calculates the transmembrane pressure difference in real time, and monitors pressure fluctuations.

[0055] The conductivity of the produced water is obtained by using an online conductivity meter installed in the produced water pipeline. The concentration of ions in the water is measured by utilizing the conductivity characteristics of the solution between the electrodes. The instrument outputs the collected conductivity signal as a digital signal or a standard analog signal after temperature compensation, and then transmits it to the central control system.

[0056] When the effluent flow rate increases, the resistance of water flow through the membrane increases. In order to maintain the same flux, the system must provide a higher driving force, which is a larger transmembrane pressure differential. An increased transmembrane pressure differential means a larger pressure difference across the membrane, and the load on the membrane structure increases accordingly. At this time, some salts will more easily penetrate the membrane pores or membrane surface defects under high pressure, resulting in an increase in the salt concentration in the product water, which manifests as an increase in conductivity.

[0057] When water pressure continues to rise, it indicates that the water flow encounters greater resistance at the membrane surface or in the membrane pores. This is usually due to partial blockage of the membrane surface or pores by contaminants. Simultaneously, if the permeate conductivity also increases, it indicates a decrease in the membrane's desalination capacity, meaning more salt is permeating through the membrane into the permeate. The combination of these two factors suggests that membrane fouling is worsening, leading to an increase in the antifouling membrane effluent flow state index.

[0058] Based on the correlation strength between effluent flow rate, effluent pressure, product water conductivity, and the stability of the antifouling membrane outlet flow state index, and combined with historical operating patterns or empirical rules, the weights of the three are initially assigned. The preset index-weight mapping rules are then retrieved from the database, and the weight ranges for different operating scenarios are determined through interval mapping tables or function fitting methods. Subsequently, the real-time collected effluent flow rate, effluent pressure, and product water conductivity are normalized and substituted into the mapping rules to calculate the preliminary weight coefficients. If the sum of the weights is not equal to 1, normalization correction is performed to ensure that the sum of the weights of the three is 1 and each is in the interval [0,1].

[0059] The antifouling membrane outlet flow state index was analyzed based on the outlet flow state parameters.

[0060] The antifouling membrane outlet flow state index is a quantitative indicator of the degree of influence of effluent flow rate, effluent pressure, and product water conductivity on the antifouling membrane outlet flow state index. The specific analysis process is as follows: After normalizing the collected effluent flow rate, effluent pressure, and product water conductivity, the data are combined in a weighted manner to obtain the antifouling membrane outlet flow state index.

[0061] , Where G represents the antifouling membrane outlet flow state index, α i b represents the normalization coefficient of the flow state parameters at the outlet of each antifouling membrane. i The parameters represent the outlet water flow state parameters of each antifouling membrane, i=1, 2, 3, where i=1 represents the outlet water flow rate, i=2 represents the outlet water pressure, i=3 represents the product water conductivity, α1 represents the outlet water flow rate normalization coefficient, α2 represents the outlet water pressure normalization coefficient, and α3 represents the product water conductivity normalization coefficient.

[0062] Furthermore, the status tags of the antifouling membrane array were determined, and the specific analysis method is as follows: Extract the preset threshold values ​​for the antifouling membrane outlet flow state index from the database.

[0063] If the antifouling membrane outlet flow state index is greater than or equal to the antifouling membrane outlet flow state index threshold, the antifouling membrane string status label will be determined as an antifouling membrane abnormal label.

[0064] It should be noted that when the system detects that the antifouling membrane outlet flow state index is greater than or equal to the antifouling membrane outlet flow state index threshold, it indicates that the antifouling membrane string may have problems such as abnormal flow or membrane blockage, and the operating status deviates from the normal range. The membrane string may be at risk of failure or increased fouling. At this time, the system will determine the antifouling membrane string status label as an antifouling membrane abnormal label.

[0065] If the flow state index of the antifouling membrane outlet is less than the threshold of the antifouling membrane outlet flow state index, the status label of the antifouling membrane string will be determined as the normal label of the antifouling membrane.

[0066] It should be noted that when the system detects that the antifouling membrane outlet flow state index is less than the antifouling membrane outlet flow state index threshold, it indicates that the antifouling membrane string is operating normally, the outlet flow rate is within the expected range, and there is no serious blockage or abnormal load on the membrane surface. At this time, the membrane module is operating stably, and the system determines the antifouling membrane string status label as the normal antifouling membrane label.

[0067] Furthermore, the load parameters of the seawater desalination membrane were collected simultaneously, the membrane segment load of the seawater desalination membrane was analyzed, and the status label of the seawater desalination membrane was determined. The specific analysis method is as follows: Collect the concentrate flow rate, permeate flow rate, and effective membrane area of ​​the seawater desalination membrane.

[0068] Using the outlet flow state index of the antifouling membrane as the influent flow rate of the first section of the seawater desalination membrane, the influent and concentrate flow rates of each membrane section are recursively calculated based on the water conservation relationship. Combined with the product flow rate and effective membrane area of ​​each section, the per-unit area flux of the membrane section is calculated and recorded as the membrane section load of the seawater desalination membrane.

[0069] It should be noted that concentrate flow rate refers to the volumetric flow rate of high-concentration brine (concentrate) that does not pass through the membrane during the reverse osmosis membrane module's separation process, discharged from the concentrate outlet. This parameter reflects the membrane system's retention rate and recovery rate. The concentrate discharge rate is collected in real time by a turbine flow meter on the concentrate discharge pipeline. The digital signal output by the sensor is transmitted to the central control unit via the data acquisition module. The system periodically records and calculates the average concentrate flow rate to determine the concentration polarization degree of the membrane section and changes in the overall operating load.

[0070] Permeate flow rate refers to the flow rate of permeate water produced by the reverse osmosis membrane module. It is used to measure the water production capacity and operational stability of the membrane module. The pure water flow rate permeates the membrane is monitored in real time by collecting data from the turbine flow meter on the permeate outlet pipeline.

[0071] Effective membrane area refers to the actual surface area of ​​the membrane in a reverse osmosis membrane module that participates in filtration and permeation. It is a fundamental parameter for calculating membrane flux and comparing membrane segment performance. This parameter is usually provided by the membrane manufacturer. During the parameter configuration phase, the system automatically calculates the total effective membrane area based on the membrane model, unit effective area, and number of membrane elements, and stores it in a parameter table, which can be directly retrieved when needed.

[0072] In one specific embodiment, the system uses the flow state index of the antifouling membrane outlet as the starting point for the feed water flow rate of the first section of the seawater desalination membrane. Based on the water conservation principle, the flow rate of each membrane section is recursively calculated. The specific process is as follows: The system first collects the flow state index of the antifouling membrane outlet and the permeate flow rate data of each seawater desalination membrane section in real time. The concentrate flow rate of the first section is calculated as the feed water flow rate minus the permeate flow rate of that section. Then, this concentrate flow rate is used as the feed water flow rate input for the next section, and this process is repeated until the last membrane section. Through this process, the system can obtain the feed water and concentrate flow rate distribution of each membrane section. Next, the system combines the permeate flow rate of each membrane section with its corresponding effective membrane area to obtain the flux per unit area, i.e., the membrane section load, which reflects the membrane's working intensity and permeation efficiency.

[0073] Extract the membrane segment load threshold of the seawater desalination membrane from the database.

[0074] If the membrane segment load of the seawater desalination membrane is greater than or equal to the membrane segment load threshold, the seawater desalination membrane status label will be recorded as an abnormal label.

[0075] It should be noted that when the membrane segment load of the seawater desalination membrane is greater than or equal to the membrane segment load threshold, it indicates that the membrane segment is under excessive operating pressure or flow load, which may lead to increased pollution, decreased desalination performance, or membrane damage. In this case, the membrane segment may need to be reduced in load, cleaned, or otherwise maintained. The seawater desalination membrane status label should be marked as an abnormal label.

[0076] If the membrane segment load of the seawater desalination membrane is less than the membrane segment load threshold, the seawater desalination membrane status label will be recorded as the seawater desalination membrane normal label.

[0077] It should be noted that when the membrane segment load of the seawater desalination membrane is less than the membrane segment load threshold, it means that the membrane segment is operating within the safe load range, the membrane surface is not subjected to excessive pressure, and the desalination performance and product water quality are at normal levels. At this time, the membrane segment is operating stably and can maintain the existing flow and pressure parameters. The seawater desalination membrane status label should be recorded as the seawater desalination membrane normal label.

[0078] The second path for water treatment control is determined by combining the status tags of the antifouling membrane string and the seawater desalination membrane, and then executed.

[0079] Furthermore, by combining the status tags of the antifouling membrane string and the seawater desalination membrane, the second path for water treatment control was determined. The specific analysis method is as follows: If the status label of the antifouling membrane assembly is an abnormal label and the status label of the seawater desalination membrane is a normal label, the second path of water treatment control will be recorded as the first regulation of multi-membrane synergy in the later stage.

[0080] It should be noted that when the status label of the antifouling membrane string is "abnormal" and the status label of the seawater desalination membrane is "normal," it means that the upstream antifouling membrane has experienced an operational anomaly, but the downstream seawater desalination membrane has not yet been significantly affected and is still operating within its normal load range. This indicates that there is a potential risk associated with the antifouling membrane, which, if not addressed promptly, may gradually affect the operating efficiency of the seawater desalination membrane and water quality. Therefore, it is necessary to adjust the valve opening of the antifouling membrane based on its outlet flow rate. This second path of water treatment control is referred to as the downstream multi-membrane coordinated first regulation.

[0081] If the status label of the antifouling membrane assembly is normal and the status label of the seawater desalination membrane is abnormal, the second path of water treatment control is recorded as the second regulation of multi-membrane synergy in the later stage.

[0082] It should be noted that when the status label of the antifouling membrane assembly is normal and the status label of the seawater desalination membrane is abnormal, it indicates that the upstream antifouling membrane is operating normally and the water flow and quality meet expectations. However, the downstream seawater desalination membrane has problems such as overload, fouling, or decreased desalination performance. This situation indicates that the abnormality mainly occurs in the seawater desalination membrane itself, rather than being caused by the load or fouling transmitted by the antifouling membrane. The system or operators need to focus on cleaning the seawater desalination membrane section and adjust the valve opening of the seawater desalination membrane. The second path of water treatment control is recorded as the downstream multi-membrane coordinated second regulation.

[0083] If the status label of the antifouling membrane assembly is an abnormal label and the status label of the seawater desalination membrane is an abnormal label, the second path of water treatment control will be recorded as the third regulation of multi-membrane synergy in the later stage.

[0084] It should be noted that when both the antifouling membrane string status label and the seawater desalination membrane status label are abnormal, it means that both the antifouling membrane and the seawater desalination membrane are experiencing operational abnormalities: the upstream antifouling membrane may be experiencing insufficient flow or partial blockage, while the downstream seawater desalination membrane has been subjected to excessive load or fouling, potentially leading to decreased desalination performance and unstable effluent quality. This status indicates a high risk to the entire membrane system. If not addressed promptly, it could result in membrane damage, reduced permeate production, or substandard water quality. Therefore, it is necessary to adjust the valve openings of both the antifouling membrane and the seawater desalination membrane. This second path of water treatment control is referred to as the downstream multi-membrane collaborative third regulation.

[0085] If the status label of the antifouling membrane module is normal and the status label of the seawater desalination membrane is normal, the second path of water treatment control is marked as no adjustment is required. The membrane module is considered to be operating normally. The current main pump frequency and valve opening are maintained, and normal system adjustment information is generated.

[0086] It should be noted that when the status label of the antifouling membrane module and the seawater desalination membrane are both normal, it means that both the upstream and downstream membrane sections are operating stably without abnormal loads or water quality fluctuations. At this time, the entire membrane module is considered to be operating normally, and the second path of water treatment control is marked as not requiring adjustment. The current main pump frequency and valve openings can be kept unchanged to avoid unnecessary adjustment operations.

[0087] Furthermore, the primary regulation of multi-membrane synergy in the latter stage is analyzed using the following methods: The deviation of the antifouling membrane outlet flow state index is obtained based on the antifouling membrane outlet flow state index and the threshold of the antifouling membrane outlet flow state index. The single adjustment limit of the antifouling membrane valve is determined based on the deviation of the antifouling membrane outlet flow state index.

[0088] It should be noted that the deviation of the antifouling membrane outlet flow state index is obtained by subtracting the threshold of the antifouling membrane outlet flow state index from the antifouling membrane outlet flow state index.

[0089] In this embodiment, the system pre-defines the correspondence rules between the antifouling membrane outlet flow state index deviation and the proportion of the single adjustment limit of the antifouling membrane valve, and stores these rules in a configuration file or parameter table for subsequent unified invocation. During operation, the system first calculates the antifouling membrane outlet flow state index deviation to reflect the degree of deviation of the antifouling membrane outlet flow state index from the target flow rate. Then, based on the preset rules, the system establishes the correspondence between the antifouling membrane outlet flow state index deviation and the proportion of the single adjustment limit of the antifouling membrane valve through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching single adjustment limit proportion. The core logic is that a larger antifouling membrane outlet flow state index deviation indicates more significant fluctuations in the antifouling membrane outlet flow state index; therefore, to maintain a stable flux of the antifouling membrane string, the single adjustment limit should be increased.

[0090] The main pump frequency adjustment value and the reduction in the antifouling membrane flow valve opening are determined based on the deviation of the antifouling membrane outlet water flow state index.

[0091] It should be noted that in this embodiment, the system first determines the main pump regulating flow share and valve fine-tuning diversion value based on the deviation of the antifouling membrane outlet water flow state index, and then determines the main pump frequency regulation value and the reduction amount of the antifouling membrane flow valve opening based on the main pump regulating flow share and valve fine-tuning diversion value.

[0092] In this embodiment, the system pre-sets the correspondence rules between the antifouling membrane outlet flow state index deviation and the main pump regulating flow share and valve fine-tuning diversion value, and stores them in a configuration file or parameter table for subsequent unified invocation. During operation, the system first calculates the antifouling membrane outlet flow state index deviation to reflect the degree of deviation of the outlet flow rate from the target flow rate. Then, according to the preset rules, it establishes the correspondence between the deviation value and the main pump regulating flow share and valve fine-tuning diversion value through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching flow regulation share and diversion flow rate. The core logic is that a larger flow deviation indicates a more significant fluctuation in the antifouling membrane outlet flow state index. To better correct these fluctuations, the main pump regulating flow share and valve fine-tuning diversion value are larger. Subsequently, based on the calculated main pump regulating flow share and valve fine-tuning diversion value, the system determines the main pump frequency regulation value and the reduction in the antifouling membrane flow valve opening according to the preset mapping rules, achieving coordinated regulation of the main pump and valves, thereby precisely controlling the membrane flow rate and maintaining the safe and stable operation of the antifouling membrane and subsequent membrane stages.

[0093] Extract the preset threshold for the reduction in the opening of the antifouling membrane flow valve from the database.

[0094] If the reduction in the opening of the antifouling membrane flow valve is greater than or equal to the threshold for the reduction in the opening of the antifouling membrane flow valve, the single adjustment range of the antifouling membrane valve opening is determined based on the ratio of the reduction in the opening of the antifouling membrane flow valve to the single adjustment limit range of the antifouling membrane valve, and the antifouling membrane valve adjustment is executed.

[0095] It should be noted that if the reduction in the antifouling membrane flow valve opening is greater than or equal to the threshold for the reduction in the antifouling membrane flow valve opening, it indicates a significant deviation in the flow state index of the antifouling membrane outlet water, requiring more substantial valve adjustment to restore the flow rate to the target range. In this case, the system will combine the reduction in the antifouling membrane flow valve opening with the proportion of the single adjustment limit of the antifouling membrane valve to calculate the valve opening range for a single adjustment, thereby achieving controlled and gradual adjustment.

[0096] It should be explained that the single adjustment range of the antifouling membrane valve opening is obtained by multiplying the reduction in the opening of the antifouling membrane flow valve by the ratio of the single adjustment limit of the antifouling membrane valve.

[0097] After each adjustment of the antifouling membrane valve, the flow state index of the antifouling membrane outlet water is collected. If the flow state index of the antifouling membrane outlet water meets the condition of being less than or equal to the threshold condition within the limit number of adjustments, the adjustment of the antifouling membrane valve is completed. If the condition of being less than or equal to the threshold condition does not exist, an early warning message is generated.

[0098] In this embodiment, the system pre-sets the correspondence between the reduction in the opening of the antifouling membrane flow valve and the number of limiting adjustments, and stores these rules in a configuration file or parameter table for unified invocation. During operation, the system first calculates the reduction in the opening of the antifouling membrane valve within the current adjustment cycle, and determines the corresponding number of limiting adjustments based on the preset rules through interval mapping tables, function fitting, or interpolation. The core logic is that the larger the reduction in the opening of the antifouling membrane flow valve, the stronger the adjustment force taken by the system to reduce the membrane load or alleviate fouling, and the more obvious the dynamic changes in membrane flux and transmembrane pressure difference. At this time, the system needs to gradually stabilize the operating state through multiple subdivided limiting adjustment processes to prevent membrane shock or water quality fluctuations caused by a one-time adjustment. Therefore, the larger the reduction in valve opening, the more limiting adjustments are required.

[0099] It should be noted that if the antifouling membrane outlet flow state index is less than or equal to the threshold value within the limited number of adjustments, it means that after one or more controlled adjustments, the antifouling membrane outlet flow state index has recovered to a safe range or close to the target value, and the flow deviation has been effectively corrected. This means that the antifouling membrane valve adjustment action has been successfully implemented, and the system can continue to monitor the flow state while maintaining the existing operating parameters to ensure the long-term stable and safe operation of the membrane section, thus completing the antifouling membrane valve adjustment.

[0100] If the system does not have a condition where the antifouling membrane outlet flow state index is less than or equal to the antifouling membrane outlet flow state index threshold within the limited number of adjustments, it indicates that after multiple adjustments, the antifouling membrane outlet flow state index has not yet recovered to a safe or target range, and there is a risk of continuous abnormality. At this time, the system will automatically generate an early warning message to remind operators that the antifouling membrane may be severely blocked, the membrane surface may be fouled, or the valve adjustment may fail.

[0101] In this embodiment, the warning message could be: "Attention! No antifouling membrane outlet flow state index meets the conditions." If the reduction in the opening of the antifouling membrane flow valve is less than the threshold for the reduction in the opening of the antifouling membrane flow valve, the antifouling membrane valve regulation is executed directly.

[0102] It should be noted that if the reduction in the opening of the antifouling membrane flow valve is less than the threshold for the reduction in the opening of the antifouling membrane flow valve, it indicates that the deviation of the current antifouling membrane outlet flow state index is small, and the membrane section is operating close to the target state. No significant adjustment is required. In this case, the system can directly perform antifouling membrane valve adjustment, that is, adjust the antifouling membrane valve quickly and smoothly according to the calculated reduction in opening, so that the outlet flow gradually returns to the target range, thereby correcting the slight deviation.

[0103] Simultaneously determine the valve opening increase value of the seawater desalination membrane based on the decrease in the flow rate valve opening of the antifouling membrane, and perform valve adjustment of the seawater desalination membrane.

[0104] It should be noted that while adjusting the antifouling membrane valves, the system simultaneously calculates the increase in the valve opening of the seawater desalination membrane based on the decrease in the antifouling membrane flow rate valve opening. The core logic is that when the flow rate of the upstream antifouling membrane increases, leading to an increase in the flow state index at the antifouling membrane outlet, the valve opening needs to be appropriately increased to cope with the flow rate change in order to maintain stable water supply and target production in the downstream seawater desalination membrane stage. Adjusting the seawater desalination membrane valves means that the system will adjust the valves according to the calculated increase in opening, enabling coordinated flow control between the upstream and downstream membrane stages, maintaining the hydraulic balance of the entire membrane system, stable effluent quality, and safe and efficient operation.

[0105] In this embodiment, the system also establishes a correspondence rule between the decrease in the antifouling membrane flow valve opening and the increase in the seawater desalination membrane valve opening, and stores this rule in the system parameter table for unified retrieval. During operation, when the system detects a decrease in the antifouling membrane valve opening, it indicates that the antifouling membrane is experiencing a flow surge. To maintain the balance between the system's total flux and recovery rate, the water intake capacity of the seawater desalination membrane needs to be increased simultaneously. Based on a preset mapping relationship, the system calculates the increase in the seawater desalination membrane valve opening that matches the current decrease in the antifouling membrane opening through an interval mapping table or function fitting. The logical connection is that the larger the decrease in the antifouling membrane valve opening, the more flow the seawater desalination membrane needs to receive, and the corresponding increase in the seawater desalination membrane valve opening should be increased.

[0106] The regulation of the antifouling membrane valve and the regulation of the seawater desalination membrane valve are combined as the first regulation in the downstream multi-membrane synergy.

[0107] Furthermore, the second regulation of multi-membrane synergy in the latter stage is analyzed in the following ways: The membrane segment load deviation value of the seawater desalination membrane is obtained based on the membrane segment load and the membrane segment load threshold value. The valve reduction amount of the seawater desalination membrane is determined according to the membrane segment load deviation value, and the valve regulation of the seawater desalination membrane is performed.

[0108] It should be noted that the membrane segment load deviation value of the seawater desalination membrane is obtained by subtracting the membrane segment load threshold of the seawater desalination membrane from the membrane segment load.

[0109] In this embodiment, the system pre-defines the correspondence rules between the load deviation value of the seawater desalination membrane segment and the valve reduction amount of the seawater desalination membrane, and stores them in a configuration file or parameter table for subsequent unified use. During operation, the system first calculates the load deviation value of the seawater desalination membrane segment to reflect the degree of deviation between the actual load and the target load of the membrane segment. Then, according to the preset rules, the system establishes the correspondence between the load deviation value of the seawater desalination membrane segment and the valve reduction amount of the seawater desalination membrane through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching valve reduction amount. The core logic is that the larger the load deviation value of the seawater desalination membrane segment, the more significant the pressure or flow load fluctuations experienced by the membrane segment. Therefore, when the load deviation value of the seawater desalination membrane segment is larger, the absolute value of the valve reduction amount of the seawater desalination membrane should be larger in order to smooth out these fluctuations.

[0110] Simultaneously, based on the valve reduction amount of the seawater desalination membrane, the reduction amount of the antifouling membrane flow valve opening and the reduction amount of the freshwater membrane valve are determined, and antifouling membrane valve regulation is implemented.

[0111] It should be noted that determining the reduction in the antifouling membrane flow valve opening and the freshwater membrane valve opening based on the reduction in the seawater desalination membrane valve means that when the system performs seawater desalination membrane regulation, it will adjust the valve openings of the upstream membrane sections in tandem to maintain overall hydraulic balance and stable operation. Specifically: when the seawater desalination membrane valve is lowered, the downstream flow decreases. If the upstream antifouling membrane and freshwater membrane valves are not adjusted, the flow rate of the antifouling membrane may be too high, leading to excessive membrane scouring, uneven water pressure, or water quality fluctuations. By reducing the opening of the upstream membrane valves in tandem, the system can simultaneously reduce the flow rate of the antifouling membrane, enabling the antifouling membrane and the seawater desalination membrane to work together and avoid membrane damage or water quality abnormalities caused by sudden flow changes.

[0112] In this embodiment, the system pre-sets the correspondence rules between the reduction amount of the seawater desalination membrane valve, the reduction amount of the antifouling membrane flow valve opening, and the reduction amount of the freshwater membrane valve, and stores these rules in a configuration file or parameter table for subsequent unified invocation. During operation, the system first calculates the actual reduction amount of the seawater desalination membrane valve to reflect the magnitude of valve adjustment by the downstream membrane stage to maintain hydraulic balance. Then, based on the preset rules, the system establishes the correspondence between the reduction amount of the seawater desalination membrane valve, the reduction amount of the antifouling membrane flow valve opening, and the reduction amount of the freshwater membrane valve through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching adjustment range of the upstream valves. The core logic is that the larger the reduction amount of the seawater desalination membrane valve, the more significant the decrease in downstream flow demand. If the antifouling membrane valve adjustment is insufficient, it may lead to excessive flow of the antifouling membrane or freshwater membrane, excessive membrane scouring, or water quality fluctuations; therefore, the absolute value of the corresponding reduction amount of the antifouling membrane flow valve opening should be reasonably increased.

[0113] If the membrane segment load of the seawater desalination membrane after adjustment is still greater than or equal to the membrane segment load threshold of the seawater desalination membrane, the membrane flushing procedure is initiated to perform a short-term relief operation, thereby completing the second phase of multi-membrane coordinated regulation.

[0114] It should be noted that during the execution of the membrane segment load adjustment action of the seawater desalination membrane, the system continuously monitors the change slope of the permeate conductivity and desalination rate of each seawater desalination membrane segment by linear fitting. When an increase in permeate conductivity or a decrease in desalination rate is detected, or when the change slope exceeds the preset change slope threshold in the database, the membrane flushing program is initiated to perform a short-term relief operation.

[0115] It should be added that after acquiring the time series data of each seawater desalination membrane segment, the system first establishes time series data for the permeate conductivity and desalination rate separately, ensuring that the data correspond one-to-one with the sampling time. Then, the data points of each membrane segment within the selected monitoring period are smoothed using median filtering. Next, with time as the independent variable and permeate conductivity and desalination rate as dependent variables, the least squares method is used for linear fitting to obtain straight lines, thus obtaining the slope of the changes in permeate conductivity and desalination rate.

[0116] The specific operating procedure for membrane flushing is as follows: Based on the deviation between the slope change and the slope change threshold, determine the preset flushing flow rate and the gradual increase step size. Start the flushing pump to introduce flushing water into the membrane module at the preset flow rate and the gradual increase step size. During the flushing process, the system monitors the transmembrane pressure difference, permeate flow rate, permeate conductivity, and pump operating status of each membrane segment in real time to ensure that the membrane segment is not subjected to hydraulic shock or pressure overload. After flushing is completed, slowly restore the original operating flow rate and continue to observe the recovery of permeate conductivity and desalination rate.

[0117] It should be noted that in this embodiment, the system pre-sets the correspondence rules between the slope deviation value and the preset flushing flow rate and gradual rise step size, and stores them in a configuration file or parameter table for subsequent unified invocation. During operation, the system first calculates the deviation between the slope of the monitored index and the slope threshold value to reflect the degree of deviation of the index's change rate from the allowable range. Then, according to the preset rules, the correspondence between the slope deviation and the flushing flow rate and gradual rise step size can be established through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching flushing flow rate and gradual rise step size. The core logic is that the larger the slope deviation value, the more drastic the index fluctuation. If the flushing flow rate is insufficient or the gradual rise step size is too large, it may not effectively alleviate membrane fouling or system abnormalities. Therefore, when the deviation is larger, the preset flushing flow rate should be appropriately increased, and the gradual rise step size should be appropriately decreased to ensure sufficient flushing effect.

[0118] Furthermore, the third regulation involving multi-membrane synergy in the later stage is analyzed using the following specific methods: The reduction in the opening of the antifouling membrane flow valve is determined based on the deviation of the antifouling membrane outlet flow state index. The reduction in the opening of the freshwater membrane valve and the start-up of the standby membrane string are then determined based on the reduction in the opening of the antifouling membrane flow valve.

[0119] It should be noted that determining the reduction in the freshwater membrane valve opening based on the reduction in the antifouling membrane flow rate valve means that when adjusting the flow rate of the upstream antifouling membrane, the valves in the upstream membrane section need to be adjusted in tandem to maintain overall hydraulic balance and stable operation. Specifically: when the antifouling membrane valve opening decreases, the ability to receive flow from the upstream membrane decreases. If the freshwater membrane valve is not adjusted, the antifouling membrane flow rate may be too high in the next cycle, affecting the filtration effect. Therefore, the system synchronously reduces the freshwater membrane valve opening to match the change in the antifouling membrane flow rate and ensure the stable operation of the upstream membrane section.

[0120] Meanwhile, the increased flow rate of the antifouling membrane leads to an increased flow rate to the downstream seawater desalination membrane. In order to maintain the water production and hydraulic balance of the downstream membrane section, the system will activate the backup membrane string accordingly, so that its flow rate can withstand the changes in the upstream flow rate, thereby maintaining the stability of the overall membrane system.

[0121] Obtain the load deviation value of the seawater desalination membrane segment, determine the valve opening reduction of the seawater desalination membrane, and determine the secondary reduction of the antifouling membrane flow valve opening and the secondary reduction of the freshwater membrane valve opening based on the valve opening reduction of the seawater desalination membrane.

[0122] It should be noted that the reduction in the opening of the seawater desalination membrane valve determines the secondary reduction in the opening of the antifouling membrane flow valve and the freshwater membrane valve. This means that after the seawater desalination membrane valve is adjusted, the system will perform a secondary linkage adjustment on the upstream membrane section to further optimize the flow balance between the upstream and downstream stages and the stability of system operation. Specifically, when the opening of the seawater desalination membrane valve is reduced, the downstream flow decreases. If the upstream antifouling membrane or freshwater membrane valve is not adjusted secondary, the flow may still be too high, leading to excessive membrane scouring or uneven water pressure. Based on the reduction in the seawater desalination membrane valve, the system calculates the secondary reduction in the opening of the antifouling membrane flow valve to further match the flow of the downstream membrane, ensuring a reasonable load on the antifouling membrane section. At the same time, the freshwater membrane valve is also reduced secondary to ensure that the upstream membrane sections work together and avoid excessive local flow.

[0123] The change in the opening of the freshwater membrane valve is obtained based on the reduction in the valve opening and the secondary reduction in the valve opening. This change in the valve opening is then applied to the freshwater membrane valve.

[0124] It should be noted that the change in the opening of the freshwater membrane valve is obtained by adding the decrease in the opening of the freshwater membrane valve and the second decrease in the opening of the freshwater membrane valve.

[0125] It should be added that the change in the freshwater membrane valve opening means that the system synthesizes the results of the initial adjustment of the antifouling membrane and the secondary fine-tuning of the seawater desalination membrane to obtain the final valve opening range that needs to be adjusted. Then, the calculated change in the freshwater membrane valve opening is applied to the freshwater membrane valve, that is, the system actually adjusts the valve opening according to this range so that the freshwater membrane flow rate achieves the expected change, thereby matching the flow rate changes of the antifouling membrane and the seawater desalination membrane.

[0126] The change in the opening of the antifouling membrane flow valve is obtained based on the reduction in the opening of the antifouling membrane flow valve and the secondary reduction in the opening of the antifouling membrane flow valve. The change in the opening of the antifouling membrane flow valve is then applied to the antifouling membrane flow valve.

[0127] It should be noted that the change in the opening of the antifouling membrane flow valve is obtained by adding the reduction in the opening of the antifouling membrane flow valve and the secondary reduction in the opening of the antifouling membrane flow valve.

[0128] It should be added that the change in the opening of the antifouling membrane flow valve means that the system integrates the initial adjustment of the antifouling membrane with the secondary linkage fine-tuning of the seawater desalination membrane to obtain the final valve opening adjustment range. Subsequently, the calculated change in the opening of the antifouling membrane flow valve is applied to the antifouling membrane flow valve, that is, the system actually adjusts the valve opening according to this range, so that the flow state index of the antifouling membrane outlet water gradually returns to the target range. At the same time, it coordinates with the valve adjustment of the freshwater membrane and the seawater desalination membrane to ensure the coordinated operation of the upstream and downstream membrane sections.

[0129] The amount of reduction in the valve opening of the seawater desalination membrane is recorded as the change in valve opening of the seawater desalination membrane, and the change in valve opening of the seawater desalination membrane is applied to the valve of the seawater desalination membrane.

[0130] It should be added that the change in the opening of the desalination membrane valve is applied to the desalination membrane valve. That is, the system actually adjusts the valve opening according to this range so that the flow rate of the desalination membrane is restored to the target range. At the same time, it works in coordination with the flow regulation of the upstream antifouling membrane and the freshwater membrane to ensure the hydraulic balance of the entire membrane system.

[0131] Simultaneously activate the backup membrane string. Determine the influent flow rate based on the deviation of the antifouling membrane outlet flow state index and the change in the opening of the antifouling membrane flow valve. Determine the number of backup membrane units based on the influent flow rate to alleviate overload. This completes the downstream multi-membrane coordinated third regulation. It should be noted that, based on the deviation of the antifouling membrane outlet flow state index and the change in the opening of the antifouling membrane flow valve, the target flow rate is calculated. The standby inlet valve is opened gradually in small steps. The percentage step size and residence time of each step are determined according to the target flow rate. After each step is opened, a certain residence time is maintained to monitor the transmembrane pressure difference, inlet pressure, product water flow rate, pump current, and product water conductivity between the standby and main series in real time to ensure that they are all within the allowable range and without abnormal fluctuations. Only after confirming safety can the next step be continued until the set flow rate target is achieved. In this embodiment, the system pre-defines the correspondence rules between the antifouling membrane outlet flow state index deviation and the influent flow rate, as well as between the change in the antifouling membrane flow valve opening and the influent flow rate, and stores these rules in a configuration file or parameter table for subsequent unified invocation. During operation, the system first calculates the antifouling membrane outlet flow state index deviation and the change in the antifouling membrane flow valve opening to reflect the magnitude and trend of changes in the outlet flow rate of the upstream membrane stage and the downstream membrane stage. Then, based on the preset rules, the system establishes the correspondence between the deviation value and the flow rate distribution through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching influent flow rate. The core logic is that a larger antifouling membrane outlet flow state index deviation or a more significant change in the antifouling membrane flow valve opening indicates a higher risk of flow imbalance between the upstream and downstream membrane stages. Insufficient flow rate adjustment may lead to overload of the upstream membrane or insufficient permeate from the downstream membrane. Therefore, the larger these two indicators are, the larger the influent flow rate, thereby achieving balanced regulation between the upstream and downstream membrane stages.

[0132] In this embodiment, the system pre-defines the correspondence rules between the influent flow rate and the number of standby membrane modules, and stores them in a configuration file or parameter table for subsequent unified use. During operation, the system first calculates the actual influent flow rate to reflect the current load and flow demand of the membrane system. Then, based on the preset rules, it establishes the correspondence between the influent flow rate and the number of standby membrane modules through interval mapping tables, function fitting, or interpolation methods, thereby determining the matching number of standby membrane modules. The core logic is that the higher the influent flow rate, the higher the load on the membrane system. If the number of standby membrane modules is insufficient, a failure or need for cleaning of the main membrane module may lead to a decrease in water production capacity or abnormal effluent quality; therefore, a higher influent flow rate requires more standby membrane modules.

[0133] The embodiments of the present invention provide, as follows Figure 2 The flowchart shown is a water treatment control method based on multi-membrane synergistic purification. The process of this method may include the following steps: First, monitor the turbidity of the freshwater membrane effluent and the transmembrane pressure difference to determine the first water treatment control path. Then, determine the second water treatment control path by analyzing the flow state index of the antifouling membrane outlet and the membrane segment load state of the seawater desalination membrane. Based on the combination of the status labels of the antifouling membrane and the seawater desalination membrane, perform the following three phases of multi-membrane synergistic regulation: first, second, and third phases.

[0134] See Figure 4The diagram shown is a mind map of a water treatment control system based on multi-membrane synergistic purification provided by an embodiment of the present invention. This system achieves safe and stable operation of the seawater desalination membrane by linking and monitoring and adjusting the upstream and downstream membrane stages. The system periodically collects parameters such as the turbidity and transmembrane pressure difference of the freshwater membrane effluent, the flow state index of the antifouling membrane outlet, and the load of the seawater desalination membrane stage. Based on the determined valve opening adjustment amount and the main pump flow share, the system can execute different water treatment control paths for different operating states, as well as activate the backup membrane string and divert flow, ensuring the coordinated operation of the antifouling membrane, freshwater membrane, and seawater desalination membrane.

[0135] The above embodiments can be implemented, in whole or in part, by software, hardware (such as circuits), firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the flow or function according to the embodiments of the present invention is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. Computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. A computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. Available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media. Semiconductor media can be solid-state drives.

[0136] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0137] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0138] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0139] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0140] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0141] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A water treatment control system based on multi-membrane synergistic purification, characterized in that, The system includes: a water treatment control first path module, a multi-membrane state tag determination module, and a water treatment control second path determination module; The water treatment control first path module is used to collect the effluent parameters of the freshwater membrane string, thereby analyzing and determining the water treatment control first path, and when the water treatment control first path is the front-end regulation, to perform coordinated regulation of the freshwater membrane and the antifouling membrane. The multi-membrane status label determination module is used to collect flow parameters of the antifouling membrane, analyze the flow state index of the antifouling membrane outlet water, determine the status label of the antifouling membrane string, and simultaneously collect load parameters of the seawater desalination membrane, analyze the membrane segment load of the seawater desalination membrane, and determine the status label of the seawater desalination membrane. The water treatment control second path determination module is used to determine the water treatment control second path by combining the antifouling membrane string status tag and the seawater desalination membrane status tag, and then execute it.

2. The water treatment control method based on multi-membrane synergistic purification according to claim 1, characterized in that, The analysis determines the first control path for water treatment, and when the first control path is front-end regulation, the synergistic regulation of the freshwater membrane and the antifouling membrane is performed. The specific analysis method is as follows: Within the preset monitoring period, the effluent turbidity and transmembrane pressure difference of the freshwater membrane string are collected. Extract the effluent turbidity threshold and transmembrane pressure difference threshold of the freshwater membrane string; If the transmembrane pressure difference is greater than or equal to the transmembrane pressure difference threshold, the first path of water treatment control will be determined as requiring no adjustment, and an alarm message will be generated. If the transmembrane pressure difference is less than the transmembrane pressure difference threshold and the effluent turbidity is greater than the effluent turbidity threshold, the first path of water treatment control will be determined as the front-end regulation. If the transmembrane pressure difference is less than the transmembrane pressure difference threshold and the effluent turbidity is less than or equal to the effluent turbidity threshold, the first path of water treatment control is determined to be no adjustment required. The deviation value of turbidity of freshwater membrane effluent is obtained based on the turbidity of freshwater membrane effluent and the turbidity threshold. The reduction value of the freshwater membrane valve opening is determined based on the turbidity deviation value of the freshwater membrane effluent, and the reduction value of the antifouling membrane valve opening is determined based on the reduction value of the freshwater membrane valve opening. The opening of the freshwater membrane valve is adjusted based on the decrease in the opening value of the freshwater membrane valve, and the opening of the antifouling membrane valve is adjusted based on the decrease in the opening value of the antifouling membrane valve, thereby completing the front-end regulation.

3. The water treatment control method based on multi-membrane synergistic purification according to claim 1, characterized in that, The specific analysis method for the antifouling membrane outlet water flow state index is as follows: Collect the outlet water flow parameters of the antifouling membrane, including outlet flow rate, outlet pressure, and product water conductivity; Analyze the antifouling membrane outlet flow state index based on the antifouling membrane outlet flow state parameters; The antifouling membrane outlet flow state index is a quantitative indicator of the degree of influence of effluent flow rate, effluent pressure, and product water conductivity on the antifouling membrane outlet flow state index. The specific analysis process is as follows: After normalizing the collected effluent flow rate, effluent pressure, and product water conductivity, they are combined in a weighted manner to obtain the antifouling membrane outlet flow state index.

4. The water treatment control method based on multi-membrane synergistic purification according to claim 3, characterized in that, The specific analysis method for determining the status tags of the antifouling membrane assembly is as follows: Extract the threshold value of the flow state index of the antifouling membrane outlet water; If the antifouling membrane outlet flow state index is greater than or equal to the antifouling membrane outlet flow state index threshold, the antifouling membrane string status label will be determined as an antifouling membrane abnormal label. If the flow state index of the antifouling membrane outlet is less than the threshold of the antifouling membrane outlet flow state index, the status label of the antifouling membrane string will be determined as the normal label of the antifouling membrane.

5. The water treatment control method based on multi-membrane synergistic purification according to claim 1, characterized in that, The loading parameters of the seawater desalination membrane are collected simultaneously, the membrane segment load is analyzed, and the status label of the seawater desalination membrane is determined. The specific analysis method is as follows: Collect the concentrate flow rate, permeate flow rate, and effective membrane area of ​​the seawater desalination membrane; The flow state index of the antifouling membrane outlet is used as the influent flow rate of the first section of the seawater desalination membrane. Based on the water conservation relationship, the influent and concentrate flow rates of each membrane section are calculated recursively. Combined with the product flow rate and effective membrane area of ​​each section, the per-unit area flux of the membrane section is calculated and recorded as the membrane section load of the seawater desalination membrane. Extracting the membrane segment load threshold of seawater desalination membranes; If the membrane segment load of the seawater desalination membrane is greater than or equal to the membrane segment load threshold of the seawater desalination membrane, then the seawater desalination membrane status label is recorded as the seawater desalination membrane abnormal label. If the membrane segment load of the seawater desalination membrane is less than the membrane segment load threshold, the seawater desalination membrane status label will be recorded as the seawater desalination membrane normal label.

6. The water treatment control method based on multi-membrane synergistic purification according to claim 1, characterized in that, The method for determining the second path of water treatment control by combining the status tags of the antifouling membrane assembly and the seawater desalination membrane is as follows: If the status label of the antifouling membrane assembly is an abnormal label and the status label of the seawater desalination membrane is a normal label, the second path of water treatment control will be recorded as the first regulation of multi-membrane synergy in the later stage. If the status label of the antifouling membrane assembly is normal and the status label of the seawater desalination membrane is abnormal, the second path of water treatment control is recorded as the second regulation of multi-membrane synergy in the later stage. If the status label of the antifouling membrane assembly is an abnormal label and the status label of the seawater desalination membrane is an abnormal label, the second path of water treatment control will be recorded as the third regulation of multi-membrane synergy in the later stage. If the status label of the antifouling membrane module is normal and the status label of the seawater desalination membrane is normal, the second path of water treatment control is marked as no adjustment is required. The membrane module is considered to be operating normally. The current main pump frequency and valve opening are maintained, and normal system adjustment information is generated.

7. A water treatment control method based on multi-membrane synergistic purification according to claim 6, characterized in that, The specific analysis method for the subsequent multi-membrane synergistic first regulation is as follows: The deviation of the antifouling membrane outlet flow state index is obtained based on the antifouling membrane outlet flow state index and the antifouling membrane outlet flow state index threshold. The single adjustment limit amplitude ratio of the antifouling membrane valve is determined based on the deviation of the antifouling membrane outlet flow state index. The main pump frequency adjustment value and the reduction in the antifouling membrane flow valve opening are determined based on the deviation of the antifouling membrane outlet water flow state index. Extract the threshold for the reduction in the opening degree of the antifouling membrane flow valve; If the reduction in the opening of the antifouling membrane flow valve is greater than or equal to the threshold value, the single adjustment range of the antifouling membrane valve opening is determined based on the reduction in the opening of the antifouling membrane flow valve and the ratio of the single adjustment limit range of the antifouling membrane valve. The antifouling membrane valve adjustment is then performed. After each adjustment, the antifouling membrane outlet water flow state index is collected. If the antifouling membrane outlet water flow state index is within the limit number of adjustments and there is a condition that the antifouling membrane outlet water flow state index is less than or equal to the threshold value, the antifouling membrane valve adjustment is completed. If there is no condition that the antifouling membrane outlet water flow state index is less than or equal to the threshold value, an early warning message is generated. If the reduction in the opening of the antifouling membrane flow valve is less than the threshold for the reduction in the opening of the antifouling membrane flow valve, the antifouling membrane valve regulation is executed directly. Simultaneously determine the valve opening increase value of the seawater desalination membrane based on the decrease in the flow rate valve opening of the antifouling membrane, and perform valve adjustment of the seawater desalination membrane; The regulation of the antifouling membrane valve and the regulation of the seawater desalination membrane valve are combined as the first regulation in the downstream multi-membrane synergy.

8. A water treatment control method based on multi-membrane synergistic purification according to claim 6, characterized in that, The specific analysis method for the subsequent multi-membrane synergistic second regulation is as follows: The membrane segment load deviation value of the seawater desalination membrane is obtained based on the membrane segment load and the membrane segment load threshold value of the seawater desalination membrane. The valve reduction amount of the seawater desalination membrane is determined according to the membrane segment load deviation value, and the valve adjustment of the seawater desalination membrane is performed. At the same time, the reduction amount of the antifouling membrane flow valve opening and the reduction amount of the freshwater membrane valve are determined based on the reduction amount of the seawater desalination membrane valve, and the antifouling membrane valve is adjusted accordingly. If the membrane segment load of the seawater desalination membrane after adjustment is still greater than or equal to the membrane segment load threshold of the seawater desalination membrane, the membrane flushing procedure is initiated to perform a short-term relief operation, thereby completing the second phase of multi-membrane coordinated regulation.

9. A water treatment control method based on multi-membrane synergistic purification according to claim 6, characterized in that, The specific analysis method for the subsequent multi-membrane synergistic third regulation is as follows: The reduction in the opening of the antifouling membrane flow valve is determined based on the deviation of the antifouling membrane outlet flow state index. The reduction in the opening of the freshwater membrane valve and the start-up of the standby membrane string are then determined based on the reduction in the opening of the antifouling membrane flow valve. Obtain the load deviation value of the seawater desalination membrane segment, determine the valve opening reduction of the seawater desalination membrane, and determine the secondary reduction of the antifouling membrane flow valve opening and the secondary reduction of the freshwater membrane valve opening based on the valve opening reduction of the seawater desalination membrane. The change in the opening of the freshwater membrane valve is obtained based on the reduction in the opening degree of the freshwater membrane valve and the secondary reduction in the opening degree of the freshwater membrane valve. The change in the opening degree of the freshwater membrane valve is then applied to the freshwater membrane valve. The change in the opening of the antifouling membrane flow valve is obtained based on the reduction in the opening of the antifouling membrane flow valve and the secondary reduction in the opening of the antifouling membrane flow valve. The change in the opening of the antifouling membrane flow valve is then applied to the antifouling membrane flow valve. The amount of reduction in the valve opening of the seawater desalination membrane is recorded as the change in the valve opening of the seawater desalination membrane, and the change in the valve opening of the seawater desalination membrane is applied to the valve of the seawater desalination membrane. The backup membrane string is activated simultaneously. The influent flow rate is determined based on the deviation of the antifouling membrane outlet flow state index and the change in the opening of the antifouling membrane flow valve. The number of backup membrane units is determined based on the influent flow rate to alleviate overload. This completes the third regulation of multi-membrane coordination in the later stage.

10. A water treatment control method based on multi-membrane synergistic purification, applied to a water treatment control system based on multi-membrane synergistic purification according to any one of claims 1-9, characterized in that, The method includes: collecting the effluent parameters of the freshwater membrane string, analyzing and determining the first water treatment control path, and when the first water treatment control path is the front-end regulation, performing coordinated regulation of the freshwater membrane and the antifouling membrane; Collect flow parameters of the antifouling membrane, analyze the flow state index of the antifouling membrane outlet water, determine the status label of the antifouling membrane string, and simultaneously collect load parameters of the seawater desalination membrane, analyze the membrane segment load of the seawater desalination membrane, and determine the status label of the seawater desalination membrane. The second path for water treatment control is determined by combining the status tags of the antifouling membrane string and the seawater desalination membrane, and then executed.

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