Reverse osmosis process filtration system and method

Abstract

The application provides a reverse osmosis process filtration system and method, wherein the decay gradient of pressure of water to be treated in a reverse osmosis membrane assembly is determined by the pressure distribution of the water to be treated from a water inlet to the reverse osmosis membrane, the critical steady-state pressure difference of the reverse osmosis membrane assembly to the water to be treated is determined according to the decay gradient and the flow rate of the water to be treated, the dynamic deposition pollution layer of the pollutants on the reverse osmosis membrane is determined according to the pressure difference between the water inlet and the water outlet in the reverse osmosis membrane assembly and the suspended solid concentration of the water to be treated, the pollutant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane assembly is determined by the critical steady-state pressure difference and the dynamic deposition pollution layer, and when the pollutant deposition flux exceeds the preset deposition threshold of the pollutants on the reverse osmosis membrane, the cleaning program of the reverse osmosis membrane assembly is triggered to clean the pollutants on the reverse osmosis membrane. By adopting the application, the influence of the dynamic change of the pollutant load on the membrane on the reverse osmosis membrane process filtration can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of process filtration, and more particularly, to a reverse osmosis process filtration system and method. BACKGROUND

[0002] Process filtration refers to a process in which, in industrial production or a specific process flow, impurities, particles, colloids, microorganisms, etc. in a fluid (liquid or gas) are separated out by physical, chemical or biological means to meet specific process requirements (such as purity, accuracy, safety, etc.).

[0003] In a reverse osmosis membrane filtration process, the efficient and stable operation of the reverse osmosis membrane assembly is crucial to water purification. However, in actual operation, membrane fouling seriously restricts system performance. On the one hand, the traditional process cannot accurately obtain the pressure distribution characteristics of the water to be treated in the membrane assembly, and cannot accurately analyze the relationship between the pressure decay gradient and membrane fouling, resulting in a lack of scientific basis for adjusting the operating pressure, which can easily lead to situations such as excessive pressure increasing energy consumption and damaging the membrane element, or insufficient pressure affecting water production efficiency. On the other hand, the existing technology often relies solely on the pressure difference between the inlet and outlet or the suspended solid concentration data to monitor the degree of membrane fouling, which is difficult to fully capture the dynamic variation of the pollutant load and cannot determine the pollutant deposition flux in a timely and accurate manner, resulting in a lag in triggering the cleaning program and causing excessive deposition of pollutants on the membrane surface, reducing the service life and filtration efficiency of the membrane. Therefore, how to reduce the impact of the dynamic variation of the pollutant load on the reverse osmosis membrane filtration process has become a problem faced by the industry. SUMMARY

[0004] The present application provides a reverse osmosis process filtration system and method that can reduce the impact of the dynamic variation of the pollutant load on the reverse osmosis membrane filtration process.

[0005] In a first aspect, the present application provides a reverse osmosis process filtration method, wherein a reverse osmosis membrane assembly is used to filter water to be treated, the reverse osmosis membrane assembly comprising a reverse osmosis membrane, an inlet and an outlet, and comprising the following steps:

[0006] Injecting water to be treated into the reverse osmosis membrane assembly and obtaining the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane;

[0007] Extracting the decay gradient of the pressure of the water to be treated in the reverse osmosis membrane assembly from the pressure distribution, and adjusting the operating pressure of the reverse osmosis membrane assembly on the water to be treated according to the decay gradient and the flow rate of the water to be treated, to obtain the critical steady-state pressure difference of the reverse osmosis membrane assembly on the water to be treated;

[0008] The pressure difference between the inlet and outlet of the reverse osmosis membrane module is monitored. Based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated, a dynamic load analysis of the pollutant load on the reverse osmosis membrane is performed to obtain the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane.

[0009] The pollutant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module is determined by the critical steady-state pressure difference and the dynamic deposition fouling layer. When the pollutant deposition flux exceeds the preset deposition threshold of the pollutants on the reverse osmosis membrane, the cleaning procedure of the reverse osmosis membrane module is triggered to clean the pollutants on the reverse osmosis membrane.

[0010] In some embodiments, extracting the pressure decay gradient of the water to be treated in the reverse osmosis membrane module from the pressure distribution specifically includes:

[0011] Construct a pressure curve for the water to be treated based on the pressure distribution;

[0012] Select multiple feature points on the water pressure curve;

[0013] Determine the rate of pressure change between each adjacent feature point;

[0014] The pressure decay gradient of the water to be treated in the reverse osmosis membrane module is determined based on all the pressure change rates.

[0015] In some embodiments, the steady-state adjustment of the operating pressure applied to the water to be treated by the reverse osmosis membrane module based on the decay gradient and the flow rate of the water to be treated, thereby obtaining the critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module, specifically includes:

[0016] Obtain the operating pressure applied to the water to be treated by the reverse osmosis membrane module;

[0017] Monitor the flow rate of the water to be treated;

[0018] The correlation analysis of all monitored flow velocities and the decay gradient with the operating pressure is performed to obtain the correlation adjustment value of the operating pressure;

[0019] The operating pressure applied to the water to be treated by the reverse osmosis membrane module is gradually adjusted according to the associated adjustment value, and the steady-state time period of the water to be treated in the reverse osmosis membrane module from the inlet to the reverse osmosis membrane is determined.

[0020] Monitor the steady-state pressure data corresponding to the steady-state period;

[0021] The critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module is determined based on the steady-state pressure data.

[0022] In some embodiments, dynamic load analysis is performed on the contaminant load on the reverse osmosis membrane based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated, resulting in a dynamic deposited contaminant layer on the reverse osmosis membrane, specifically including:

[0023] Determine the trends of all monitored differential pressure changes;

[0024] Monitor the suspended solids concentration of the water to be treated;

[0025] Based on the aforementioned trend and the concentrations of all monitored suspended solids, the correlation data between pressure differential and suspended solids concentration were determined.

[0026] The fluctuation state of the contaminant load on the reverse osmosis membrane is determined by the correlation data;

[0027] The dynamic deposition of contaminants on the reverse osmosis membrane is determined based on the fluctuation state.

[0028] In some embodiments, determining the contaminant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module by means of the critical steady-state pressure difference and the dynamically deposited contaminant layer specifically includes:

[0029] The reverse osmosis membrane in the reverse osmosis membrane module is divided into multiple membrane units;

[0030] The deposition flux component of each membrane unit is determined based on the critical steady-state pressure difference and the dynamically deposited contaminant layer;

[0031] The contaminant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module is determined based on all deposition flux components.

[0032] In some embodiments, triggering the cleaning procedure of the reverse osmosis membrane module to clean the contaminants on the reverse osmosis membrane when the contaminant deposition flux exceeds a preset deposition threshold for contaminants on the reverse osmosis membrane further includes: when the contaminant deposition flux is less than or equal to the preset deposition threshold for contaminants on the reverse osmosis membrane, not triggering the cleaning procedure of the reverse osmosis membrane module to clean the contaminants on the reverse osmosis membrane.

[0033] In some embodiments, a differential pressure transmitter is used to monitor the pressure difference between the inlet and outlet of the reverse osmosis membrane module.

[0034] In some embodiments, water to be treated is injected into the reverse osmosis membrane module via a water pump supply device.

[0035] In some embodiments, an electromagnetic flow meter is used to monitor the flow rate of the water to be treated.

[0036] Secondly, this application provides a reverse osmosis process filtration system, comprising:

[0037] The acquisition module is used to inject water to be treated into the reverse osmosis membrane module and acquire the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane.

[0038] The processing module is used to extract the pressure decay gradient of the water to be treated in the reverse osmosis membrane module from the pressure distribution, and to perform steady-state adjustment of the operating pressure applied to the water to be treated by the reverse osmosis membrane module according to the decay gradient and the flow rate of the water to be treated, thereby obtaining the critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module.

[0039] The processing module is also used to monitor the pressure difference between the inlet and outlet of the reverse osmosis membrane module, and to perform dynamic load analysis on the pollutant load on the reverse osmosis membrane based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated, so as to obtain the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane.

[0040] The execution module is used to determine the pollutant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module by the critical steady-state pressure difference and the dynamic deposition fouling layer. When the pollutant deposition flux exceeds the preset deposition threshold of the pollutants on the reverse osmosis membrane, the cleaning procedure of the reverse osmosis membrane module is triggered to clean the pollutants on the reverse osmosis membrane.

[0041] The technical solutions provided by the embodiments disclosed in this application have the following beneficial effects:

[0042] The reverse osmosis filtration system and method provided in this application first inject water to be treated into a reverse osmosis membrane module and obtain the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane. The decay gradient of the pressure of the water to be treated in the reverse osmosis membrane module is extracted from the pressure distribution. Based on the decay gradient and the flow rate of the water to be treated, the operating pressure applied to the water to be treated by the reverse osmosis membrane module is steadily adjusted to obtain the critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module. The pressure difference between the inlet and outlet of the reverse osmosis membrane module is monitored. Based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated, a dynamic load analysis of the pollutant load on the reverse osmosis membrane is performed to obtain the dynamic deposited fouling layer of pollutants on the reverse osmosis membrane. The pollutant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module is determined by the critical steady-state pressure difference and the dynamic deposited fouling layer. When the pollutant deposition flux exceeds a preset deposition threshold for the pollutants on the reverse osmosis membrane, a cleaning procedure is triggered to clean the pollutants on the reverse osmosis membrane.

[0043] Therefore, this application significantly reduces unnecessary energy consumption during reverse osmosis filtration by real-time monitoring and analysis of the pressure distribution and decay gradient of the feed water to the membrane surface within the reverse osmosis membrane module, combined with precise calculation of flow rate and dynamic maintenance of the minimum operating pressure (i.e., critical steady-state pressure difference) required for system operation. Simultaneously, by continuously tracking the inlet / outlet pressure difference trend and combining it with feed water suspended solids concentration data, a refined and dynamic assessment of the contaminant accumulation state on the membrane surface (i.e., dynamic deposited fouling layer) is achieved. Finally, by integrating the critical steady-state pressure difference and dynamic deposited fouling layer information, the contaminant deposition flux is calculated and compared with a preset threshold, enabling precise triggering of the cleaning procedure. Using this approach, the impact of dynamic changes in contaminant load on the membrane on reverse osmosis filtration can be reduced. Attached Figure Description

[0044] Figure 1 This is an exemplary flowchart of a reverse osmosis filtration method according to some embodiments of this application;

[0045] Figure 2 These are structural diagrams of a reverse osmosis membrane module according to some embodiments of this application;

[0046] Figure 3 This is an exemplary flowchart illustrating the determination of a dynamically deposited contamination layer according to some embodiments of this application;

[0047] Figure 4 This is a schematic diagram of the structure of a reverse osmosis filtration system according to some embodiments of this application;

[0048] Figure 5 This is a schematic diagram of the structure of a computer device for implementing a reverse osmosis filtration method according to some embodiments of this application. Detailed Implementation

[0049] To better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] refer to Figure 1 The figure is an exemplary flowchart of a reverse osmosis filtration method according to some embodiments of this application. The reverse osmosis filtration method mainly includes the following steps:

[0051] In step 101, water to be treated is injected into the reverse osmosis membrane assembly, and the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane is obtained.

[0052] In practice, a water pump supply system stably injects the water to be treated into the inlet of the reverse osmosis membrane module. Pressure sensors (such as piezoresistive pressure sensors) are installed at regular intervals (generally 10-20 cm, depending on pipe length and accuracy requirements) between the inlet and the reverse osmosis membrane. The pressure data collected by the pressure sensors is transmitted in real time to the data processing unit via a data transmission line. The data processing unit uses an interpolation algorithm (such as cubic spline interpolation) to estimate the pressure at locations where no sensors are installed based on the sensor locations and the collected pressure values, constructing a continuous pressure distribution curve. Simultaneously, a finite element analysis model is used to simulate the pressure distribution using the pressure distribution curve, the structural parameters of the reverse osmosis membrane module (such as pipe diameter and membrane area), and fluid dynamic parameters (such as water density and viscosity). The simulated pressure distribution is used as the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane. In other embodiments, other methods can also be used to determine the pressure distribution.

[0053] It should be noted that the pressure distribution in this application represents the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane, which is used to analyze the feed water status of the reverse osmosis process.

[0054] In some embodiments, reference Figure 2 As shown, this figure is a structural diagram of a reverse osmosis membrane module in some embodiments of this application, such as... Figure 2 As described above, raw water enters: Raw water flows into the module from one end and is distributed through the raw water flow network, ensuring uniform contact between the water flow and the reverse osmosis membrane. Membrane separation: Under pressure, water molecules in the raw water can pass through the reverse osmosis membrane, becoming membrane permeate water; while impurities such as salt are trapped by the membrane, forming membrane concentrate water. Permeate water and concentrate water are discharged: Membrane permeate water is collected through the permeate flow network and flows out into the central water collection pipe; membrane concentrate water is discharged from the other end of the module, completing the filtration process and achieving water purification and separation.

[0055] In step 102, the pressure decay gradient of the water to be treated in the reverse osmosis membrane module is extracted from the pressure distribution. The operating pressure applied to the water to be treated by the reverse osmosis membrane module is steadily adjusted according to the decay gradient and the flow rate of the water to be treated, thereby obtaining the critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module.

[0056] In some embodiments, extracting the pressure decay gradient of the water to be treated in the reverse osmosis membrane module from the pressure distribution can be achieved by the following steps:

[0057] Construct a pressure curve for the water to be treated based on the pressure distribution;

[0058] Select multiple feature points on the water pressure curve;

[0059] Determine the rate of pressure change between each adjacent feature point;

[0060] The pressure decay gradient of the water to be treated in the reverse osmosis membrane module is determined based on all the pressure change rates.

[0061] In specific implementation, firstly, based on the interpolation method (such as Lagrange interpolation), all pressures in the pressure distribution are fitted into a smooth and continuous pressure curve of the water to be treated, arranged in the order from the inlet to the reverse osmosis membrane. This pressure curve represents the pressure curve of the water to be treated between the inlet and the reverse osmosis membrane. Next, based on the curve characteristics, multiple feature points are selected on the water pressure curve, such as the starting point (inlet pressure point), the ending point (reverse osmosis membrane pressure point), and inflection points where the curve slope changes significantly. Simultaneously, to ensure data density, equally spaced points are selected at regular intervals (e.g., 10 cm). All of these points are used as feature points. In this process, the feature points represent key points on the curve, used to analyze the curve's characteristics. Subsequently, for each adjacent feature point, the finite difference method is used to calculate the pressure change rate between adjacent feature points by combining all pressures between them, thus obtaining the pressure change rate between each adjacent feature point. The pressure change rate reflects the parameter value of the pressure decay degree in a local area. Finally, all pressure change rates are arranged according to the position of the corresponding region, and the arrangement result is used as the pressure decay gradient of the water to be treated in the reverse osmosis membrane module. In other embodiments, other methods can also be used for extraction, which are not limited here.

[0062] It should be noted that the decay gradient in this application represents the extraction of the degree of pressure decay of the water to be treated in the reverse osmosis membrane module, which is used to analyze the pressure decay characteristics along the feed water to the reverse osmosis membrane.

[0063] In some embodiments, the operating pressure applied to the water to be treated by the reverse osmosis membrane module is steadily adjusted according to the decay gradient and the flow rate of the water to be treated, thereby obtaining the critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module. This can be achieved by the following steps:

[0064] Obtain the operating pressure applied to the water to be treated by the reverse osmosis membrane module;

[0065] Monitor the flow rate of the water to be treated;

[0066] The correlation analysis of all monitored flow velocities and the decay gradient with the operating pressure is performed to obtain the correlation adjustment value of the operating pressure;

[0067] The operating pressure applied to the water to be treated by the reverse osmosis membrane module is gradually adjusted according to the associated adjustment value, and the steady-state time period of the water to be treated in the reverse osmosis membrane module from the inlet to the reverse osmosis membrane is determined.

[0068] Monitor the steady-state pressure data corresponding to the steady-state period;

[0069] The critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module is determined based on the steady-state pressure data.

[0070] It should be noted that monitoring the decay gradient can reflect the degree of membrane fouling, while the flow rate affects the mass transfer efficiency (a high flow rate results in a strong scouring effect and slow fouling accumulation). Therefore, by combining the decay gradient and the flow rate of the water to be treated, the operating pressure can be adjusted. When the operating pressure is adjusted to just offset the increase in resistance caused by fouling and the flow rate is stable, the system reaches dynamic equilibrium. The pressure difference at this point is the critical steady-state pressure difference, which means that the pressure can maintain a stable permeate flux while avoiding excessive membrane damage or energy waste due to excessive pressure.

[0071] In specific implementation, firstly, the operating pressure applied to the water to be treated by the reverse osmosis membrane module and the preset adjustment coefficient are obtained from the database corresponding to the reverse osmosis membrane module. The operating pressure represents the pressure applied by the reverse osmosis membrane module when driving the water to be treated through the reverse osmosis membrane, and the adjustment coefficient represents a parameter indicating the degree of adjustment to the operating pressure. Simultaneously, the flow rate of the water to be treated is monitored using an electromagnetic flowmeter. Next, all monitored flow rates and decay gradients are processed dimensionlessly. Based on a grey relational analysis algorithm, the correlation between flow rate and operating pressure, and the correlation between the pressure of the water to be treated and the operating pressure are calculated using the processed monitored flow rates and decay gradients. These two correlations are multiplied by the preset adjustment coefficient, and the sum of the two multiplications is used as the correlation adjustment value of the operating pressure. This correlation adjustment value represents a parameter value indicating the degree of adjustment to the operating pressure after considering the actual pressure and flow rate of the water to be treated. Other implementation methods can also be used in other embodiments, which are not limited here.

[0072] In specific implementation, the operating pressure applied to the water to be treated by the reverse osmosis membrane module is gradually adjusted according to the associated adjustment value. The steady-state period of the water to be treated from the inlet to the reverse osmosis membrane in the reverse osmosis membrane module can be determined by the following method: the operating pressure applied to the water to be treated by the reverse osmosis membrane module is gradually adjusted according to the magnitude of the associated adjustment value (i.e., the operating pressure is gradually increased according to the magnitude of the associated adjustment value). After each adjustment, the operation is maintained for 5 minutes to allow the water flow and pressure of the water to be treated to reach a stable state. By monitoring the fluctuation of the pressure sensor data, when the pressure fluctuation range is within ±0.03MPa and lasts for 15 minutes, it is determined that the water to be treated in the reverse osmosis membrane module has entered the steady-state period. The steady-state period ends when the next pressure fluctuation range exceeds ±0.03MPa. The steady-state period represents the period during which the water flow and pressure of the water to be treated in the reverse osmosis membrane module remain relatively stable for a period of time. Other methods can also be used for gradual adjustment in other embodiments, which are not limited here.

[0073] In specific implementation, the steady-state pressure data collected by the pressure sensor during the steady-state period is recorded. Finally, the critical steady-state pressure difference applied by the reverse osmosis membrane module to the water to be treated can be determined based on the steady-state pressure data in the following way: the random noise (such as equipment operating noise and environmental interference noise) in the steady-state pressure data is removed using a moving average filtering algorithm. The average pressure difference between the inlet and the reverse osmosis membrane during the steady-state period is calculated based on the arithmetic average method combined with the noise-removed steady-state pressure data. This average pressure difference is then used as the critical steady-state pressure difference applied by the reverse osmosis membrane module to the water to be treated. Other methods can also be used to determine this in other embodiments, which are not limited here.

[0074] It should be noted that the critical steady-state pressure difference in this application refers to the critical threshold of the pressure difference between the inlet and the reverse osmosis membrane when the flow rate and pressure of the water to be treated in the reverse osmosis membrane module are in steady-state conditions (i.e., the change is minimal or essentially constant over time). It can be used to analyze the operating status monitoring and cleaning decisions of the reverse osmosis membrane.

[0075] In step 103, the pressure difference between the inlet and outlet of the reverse osmosis membrane module is monitored. Based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated, a dynamic load analysis of the pollutant load on the reverse osmosis membrane is performed to obtain the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane.

[0076] In specific implementation, monitoring the pressure difference between the inlet and outlet of the reverse osmosis membrane module can be achieved in the following way: differential pressure transmitters (such as capacitive differential pressure transmitters) can be installed at the inlet and outlet respectively. The pressure signals from the inlet and outlet are stably transmitted to the differential pressure transmitters via pressure taps. The differential pressure transmitters convert the pressure signals at both ends into standard electrical signals and use a moving average filtering algorithm to denoise the standard electrical signals, that is, to remove high-frequency noise interference from the signals, thereby obtaining the pressure difference data between the inlet and outlet. The pressure difference data is the collection of all pressure differences, and the pressure difference in the pressure difference data represents the pressure difference between the inlet and outlet of the reverse osmosis membrane module. Other monitoring methods can also be used in other embodiments, which are not limited here.

[0077] In some embodiments, reference Figure 3 As shown, this figure is an exemplary flowchart for determining the dynamically deposited fouling layer in some embodiments of this application. In this embodiment, the dynamic load analysis of the pollutant load on the reverse osmosis membrane is performed based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated. The dynamic deposition of the pollutant layer on the reverse osmosis membrane can be obtained by the following steps:

[0078] In step 1031, the changing trends of all monitored differential pressures are determined;

[0079] In step 1032, the suspended solids concentration of the water to be treated is monitored;

[0080] In step 1033, the correlation data between the pressure difference and the suspended solids concentration is determined based on the changing trend and the concentrations of all monitored suspended solids.

[0081] In step 1034, the fluctuation state of the contaminant load on the reverse osmosis membrane is determined by the correlation data;

[0082] In step 1035, the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane is determined based on the fluctuation state.

[0083] It should be noted that during reverse osmosis membrane operation, the deposition of contaminants on the membrane surface will lead to an increase in pressure differential. The suspended solids concentration of the water to be treated is a direct indicator of the contaminant load. The trend of pressure differential change (such as the rate of increase and the amplitude of fluctuation) is correlated with the fluctuation of suspended solids concentration. That is, when the suspended solids concentration suddenly increases, a large number of particles are deposited rapidly, and the pressure differential may increase sharply; when the suspended solids concentration is stable, the fouling layer accumulates slowly, and the pressure differential increases linearly. Therefore, abnormal fluctuations in the pressure differential trend (such as abrupt changes in slope and periodic fluctuations) can be correlated with the suspended solids concentration to analyze the instantaneous changes and continuous accumulation effects of contaminant load, and then infer the dynamic deposition structure of the fouling layer on the membrane surface (such as the alternating formation of loose and dense layers and the fluctuation of gel layer thickness).

[0084] In specific implementation, the variation trend of all monitored pressure differences in various time periods is calculated by combining all monitored pressure differences with the corresponding acquisition time using a time series analysis method (differential method). The variation trend represents the change trend of pressure difference over time. The time period is set based on the data acquisition frequency (time granularity). In this implementation, the time period is an integer multiple of the acquisition frequency. At the same time, an online suspended solids concentration meter is used to monitor the suspended solids concentration of the water to be treated in real time and transmit it to the data processing center. Other methods can also be used in other embodiments, which are not limited here.

[0085] In addition, in specific implementation, the correlation data between pressure difference and suspended solids concentration can be determined based on the changing trend and the concentration of all monitored suspended solids. This can be achieved by: calculating the changing trend of all monitored suspended solids concentrations in each time period using time series analysis (differential method); quantifying the similarity between the changing trend and the changing trend of suspended solids concentration in each time period using cross-correlation analysis; and using the quantified similarity values ​​as the correlation between pressure difference and suspended solids concentration. The set of all correlations is then used as the correlation data between pressure difference and suspended solids concentration. Subsequently, the fluctuation state of the pollutant load on the reverse osmosis membrane can be determined using the correlation data by: inputting the correlation data into a machine learning model based on support vector machines. This model is trained using historical pressure difference, suspended solids concentration, and corresponding pollutant load data as training samples. The machine learning model accurately classifies and predicts the fluctuation state of the pollutant load, where the fluctuation state includes whether the pollutant load is increasing, stable, or decreasing. Other methods can be used in other embodiments, which are not limited here.

[0086] In addition, in specific implementation, the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane can be determined based on the fluctuation state in the following way: the membrane fouling model based on finite element analysis is combined with the fluctuation state to adjust the pollutant deposition rate and pore blockage degree of the reverse osmosis membrane to simulate the dynamic deposition process of pollutants on the membrane surface over time. The adjusted membrane fouling model is then used as a dynamic deposition fouling layer model for the real-time distribution and evolution of pollutants, and the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane is output through this dynamic deposition fouling layer model. Other methods can also be used to determine the dynamic deposition fouling layer in other embodiments, which are not limited here.

[0087] It should be noted that the dynamically deposited fouling layer in this application refers to the fouling layer on the reverse osmosis membrane deposited over time. It can be used to analyze the fouling status of the reverse osmosis membrane, providing an intuitive and accurate basis for decision-making on the operation, maintenance, and cleaning of the membrane module.

[0088] In step 104, the pollutant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module is determined by the critical steady-state pressure difference and the dynamic deposition fouling layer. When the pollutant deposition flux exceeds the preset deposition threshold of the pollutants on the reverse osmosis membrane, the cleaning procedure of the reverse osmosis membrane module is triggered to clean the pollutants on the reverse osmosis membrane.

[0089] In some embodiments, determining the contaminant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module by means of the critical steady-state pressure difference and the dynamically deposited contaminant layer can be achieved by the following steps:

[0090] The reverse osmosis membrane in the reverse osmosis membrane module is divided into multiple membrane units;

[0091] The deposition flux component of each membrane unit is determined based on the critical steady-state pressure difference and the dynamically deposited contaminant layer;

[0092] The contaminant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module is determined based on all deposition flux components.

[0093] It should be noted that the critical steady-state pressure difference of the reverse osmosis membrane reflects the pressure required for the system to overcome membrane fouling resistance in equilibrium. It is directly related to the thickness and porosity of the fouling layer on the membrane surface and the resistance of fluid passing through the fouling layer. The evolution process of the dynamically deposited fouling layer (such as changes in deposition rate and structural compactness) reveals the accumulation law of pollutants over time through the dynamic load analysis of suspended solids concentration and pressure difference. Therefore, by coupling the analysis of the physical relationship between "pressure difference-resistance-flux" and the dynamic characteristics of the fouling layer, the macroscopic pressure response can be transformed into a quantitative characterization of the microscopic pollutant deposition rate, thereby achieving accurate calculation of deposition flux.

[0094] In practice, the first step is to digitally model the geometry of the reverse osmosis membrane using computer-aided design (CAD) technology. Then, combining this with the mesh generation method of finite element analysis, the reverse osmosis membrane in the membrane module is uniformly divided into multiple tiny membrane units to ensure accurate reflection of the characteristics of different regions on the membrane surface. Next, for each membrane unit, the critical steady-state pressure difference is substituted into Darcy's law formula based on fluid mechanics, and combined with the thickness and porosity of the dynamically deposited fouling layer at that unit (a fouling layer parameter database was established through previous experiments, and real-time values ​​were obtained using interpolation algorithms) to calculate the driving force for the flow of water to be treated. The pressure difference across the membrane unit is used to calculate the deposition flux component of contaminants on the membrane unit driven by the pressure difference, based on the membrane material characteristics and solute diffusion coefficient using the Nernst-Planck equation. This deposition flux component represents the deposition rate of contaminants on the membrane unit as the water passes through the reverse osmosis membrane. Finally, a numerical integration method (such as Simpson's rule) is used to accumulate the deposition flux components of all membrane units, and the accumulated value is taken as the contaminant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module. In other embodiments, this can be achieved in the following ways, which are not limited here.

[0095] It should be noted that the contaminant deposition flux in this application represents the rate at which contaminants are deposited on the reverse osmosis membrane in the reverse osmosis membrane module. It can be used to analyze the transport rate of the water to be treated by the reverse osmosis membrane, thereby facilitating the control of the cleaning of the reverse osmosis membrane.

[0096] In some embodiments, when the contaminant deposition flux exceeds a preset deposition threshold for contaminants on the reverse osmosis membrane, triggering a cleaning procedure for the reverse osmosis membrane module to clean the contaminants on the reverse osmosis membrane can be achieved through the following steps:

[0097] Determine a preset deposition threshold for contaminants on the reverse osmosis membrane;

[0098] When the pollutant deposition flux exceeds the preset deposition threshold of pollutants on the reverse osmosis membrane, the cleaning procedure of the reverse osmosis membrane module is triggered to clean the pollutants on the reverse osmosis membrane.

[0099] When the pollutant deposition flux is less than or equal to the preset deposition threshold of pollutants on the reverse osmosis membrane, the cleaning procedure of the reverse osmosis membrane module is not triggered to clean the pollutants on the reverse osmosis membrane.

[0100] In specific implementation, when the pollutant deposition flux exceeds the preset deposition threshold of pollutants on the reverse osmosis membrane, an audible and visual alarm is automatically triggered, a cleaning warning work order is generated, and the cleaning program is started to clean the pollutants on the reverse osmosis membrane according to the cleaning warning work order. When the pollutant deposition flux is less than or equal to the preset deposition threshold of pollutants on the reverse osmosis membrane, the pollutant deposition flux is continued to be calculated and judged, and the cleaning program of the reverse osmosis membrane module is not triggered to clean the pollutants on the reverse osmosis membrane. In other embodiments, other methods can be used for judgment, which are not limited here.

[0101] It should be noted that the deposition threshold in this application can be set according to the specific needs of the reverse osmosis membrane module. For example, if the reverse osmosis membrane module filtration process is industrial filtration, the deposition threshold can be set in a high range. If the reverse osmosis membrane module filtration process is domestic filtration, the deposition threshold can be set in a low range. In other embodiments, for example, if the water filtered by the reverse osmosis membrane module is drinking water, the deposition threshold can be set in a high range, thereby improving the filtration effect of the reverse osmosis membrane module.

[0102] In another aspect, in some embodiments, this application provides a reverse osmosis process filtration system, referencing... Figure 4 The figure is a schematic diagram of a reverse osmosis filtration system according to some embodiments of this application. The reverse osmosis filtration system 400 includes: an acquisition module 401, a processing module 402, and an execution module 403, which are described below:

[0103] The acquisition module 401 in this application is mainly used to inject water to be treated into the reverse osmosis membrane module and acquire the pressure distribution of the water to be treated from the inlet to the reverse osmosis membrane.

[0104] Processing module 402, in this application, is used to extract the decay gradient of the pressure of the water to be treated in the reverse osmosis membrane module from the pressure distribution, and to perform steady-state adjustment of the operating pressure applied to the water to be treated by the reverse osmosis membrane module according to the decay gradient and the flow rate of the water to be treated, thereby obtaining the critical steady-state pressure difference applied to the water to be treated by the reverse osmosis membrane module.

[0105] It should be noted that the processing module 402 in this application is also used to monitor the pressure difference between the inlet and outlet of the reverse osmosis membrane module, and to perform dynamic load analysis on the pollutant load on the reverse osmosis membrane based on the changing trends of all monitored pressure differences and the suspended solids concentration of the water to be treated, so as to obtain the dynamic deposition fouling layer of pollutants on the reverse osmosis membrane.

[0106] The execution module 403 in this application is mainly used to determine the pollutant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module by the critical steady-state pressure difference and the dynamic deposition fouling layer. When the pollutant deposition flux exceeds the preset deposition threshold of the pollutants on the reverse osmosis membrane, the cleaning procedure of the reverse osmosis membrane module is triggered to clean the pollutants on the reverse osmosis membrane.

[0107] In addition, this application also provides a computer device, the computer device including a memory and a processor, the memory storing code, and the processor being configured to acquire the code and execute the above-described reverse osmosis filtration method.

[0108] In some embodiments, reference Figure 5 The figure is a schematic diagram of a computer device for implementing a reverse osmosis filtration method according to some embodiments of this application. The reverse osmosis filtration method in the above embodiments can... Figure 5 The computer device shown is used to implement this, and the computer device 500 includes at least one processor 501, a communication bus 502, a memory 503, and at least one communication interface 504.

[0109] Processor 501 can be a general-purpose central processing unit (CPU) or an application-specific integrated circuit (ASIC).

[0110] The communication bus 502 can be used to transmit information between the aforementioned components.

[0111] Memory 503 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital versatile optical discs, Blu-ray discs, etc.), magnetic disks or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but not limited thereto. Memory 503 may exist independently and be connected to processor 501 via communication bus 502. Memory 503 may also be integrated with processor 501.

[0112] The memory 503 stores program code for executing the scheme of this application, and its execution is controlled by the processor 501. The processor 501 executes the program code stored in the memory 503. The program code may include one or more software modules. The method used in the above embodiments can be implemented by the processor 501 and one or more software modules in the program code in the memory 503.

[0113] Communication interface 504 uses any transceiver-like device to communicate with other devices or communication networks, such as Ethernet, radio access network (RAN), wireless local area networks (WLAN), etc.

[0114] In a specific implementation, as one example, a computer device may include multiple processors, each of which may be a single-core (single-CPU) processor or a multi-core (multi-CPU) processor. Here, a processor may refer to one or more devices, circuits, and / or processing cores used to process data (e.g., computer program instructions).

[0115] The aforementioned computer device can be a general-purpose computer device or a special-purpose computer device. In specific implementations, the computer device can be a desktop computer, a portable computer, a network server, a handheld digital assistant (PDA), a mobile phone, a tablet computer, a wireless terminal device, a communication device, or an embedded device. This application does not limit the type of computer device.

[0116] In addition, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described reverse osmosis filtration method.

[0117] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0118] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A reverse osmosis process filtration method wherein, The application discloses a method for determining critical steady state pressure difference of reverse osmosis membrane module, comprising the following steps: Filtering the water to be treated by a reverse osmosis membrane module, wherein the reverse osmosis membrane module comprises a reverse osmosis membrane, a water inlet and a water outlet, and the method comprises the following steps: Injecting the water to be treated into the reverse osmosis membrane module, and obtaining the pressure distribution of the water to be treated from the water inlet to the reverse osmosis membrane; Extracting the decay gradient of the pressure of the water to be treated in the reverse osmosis membrane module from the pressure distribution, constructing the pressure curve of the water to be treated according to the pressure distribution, selecting a plurality of characteristic points on the pressure curve, determining the pressure change rate between each adjacent characteristic point, determining the decay gradient of the pressure of the water to be treated in the reverse osmosis membrane module according to all the pressure change rates, adjusting the operating pressure of the reverse osmosis membrane module to the water to be treated according to the decay gradient and the flow rate of the water to be treated, and then obtaining the critical steady state pressure difference of the reverse osmosis membrane module to the water to be treated, obtaining the operating pressure of the reverse osmosis membrane module to the water to be treated, monitoring the flow rate of the water to be treated, and performing correlation analysis on all the monitored flow rates, the decay gradient and the operating pressure to obtain the correlation adjustment value of the operating pressure, adjusting the operating pressure of the reverse osmosis membrane module to the water to be treated according to the correlation adjustment value, and determining the steady state period of the water to be treated from the water inlet to the reverse osmosis membrane in the reverse osmosis membrane module, monitoring the steady state pressure data corresponding to the steady state period, and determining the critical steady state pressure difference of the reverse osmosis membrane module to the water to be treated according to the steady state pressure data; Monitoring the pressure difference between the water inlet and the water outlet in the reverse osmosis membrane module, performing dynamic load analysis on the pollutant load on the reverse osmosis membrane according to the change trend of all the monitored pressure differences and the suspended solid concentration of the water to be treated to obtain the dynamic deposition pollution layer of the pollutant on the reverse osmosis membrane, determining the change trend of all the monitored pressure differences, monitoring the suspended solid concentration of the water to be treated, determining the correlation degree data between the pressure difference and the suspended solid concentration according to the change trend and all the monitored suspended solid concentrations, determining the fluctuation state of the pollutant load on the reverse osmosis membrane through the correlation degree data, and determining the dynamic deposition pollution layer of the pollutant on the reverse osmosis membrane according to the fluctuation state. The critical steady-state pressure difference and the dynamic deposited contamination layer are used to determine the contamination deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module, the reverse osmosis membrane in the reverse osmosis membrane module is divided to obtain a plurality of membrane units, the deposition flux component of each membrane unit is determined according to the critical steady-state pressure difference and the dynamic deposited contamination layer, the contamination deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module is determined according to all the deposition flux components, the geometry of the reverse osmosis membrane is digitally modeled by using computer aided design (CAD) technology, and the reverse osmosis membrane in the reverse osmosis membrane module is uniformly divided into a plurality of small membrane units by combining a mesh division method of finite element analysis; then, for each membrane unit, the critical steady-state pressure difference is substituted into a Darcy's law formula based on fluid mechanics and combined with the thickness and porosity of the dynamic deposited contamination layer at the membrane unit, a contamination layer parameter database is established by using an interpolation algorithm to obtain real-time values, and the pressure difference driving the water to be treated through the membrane unit is calculated, and then the Nernst-Planck equation is used to calculate the deposition flux component of the contaminant on the membrane unit under the driving of the pressure difference, wherein the deposition flux component represents the deposition rate of the contaminant on the membrane unit when the water to be treated passes through the reverse osmosis membrane; finally, the deposition flux components of all the membrane units are calculated by using a numerical integration method, and the value obtained by the cumulative calculation is used as the contamination deposition flux on the reverse osmosis membrane in the reverse osmosis membrane module, and when the contamination deposition flux exceeds the preset deposition threshold of the contaminant on the reverse osmosis membrane, a cleaning program of the reverse osmosis membrane module is triggered to clean the contaminant on the reverse osmosis membrane.

2. The method of claim 1, wherein, When the contamination deposition flux exceeds the preset deposition threshold of the contaminant on the reverse osmosis membrane, the cleaning program of the reverse osmosis membrane module is triggered to clean the contaminant on the reverse osmosis membrane, which also includes: when the contamination deposition flux is less than or equal to the preset deposition threshold of the contaminant on the reverse osmosis membrane, the cleaning program of the reverse osmosis membrane module is not triggered to clean the contaminant on the reverse osmosis membrane.

3. The method of claim 1, wherein, The differential pressure transmitter is used to monitor the pressure difference between the water inlet and the water outlet in the reverse osmosis membrane module.

4. The method of claim 1, wherein, The water pump water supply device is used to inject the water to be treated into the reverse osmosis membrane module.

5. The method of claim 1, wherein, The electromagnetic flowmeter is used to monitor the flow rate of the water to be treated.

6. A reverse osmosis process filtration system employing the method of any one of claims 1 to 5 for reverse osmosis process filtration, characterised in that, The system comprises: The acquisition module is used to inject the water to be treated into the reverse osmosis membrane module and acquire the pressure distribution of the water to be treated from the water inlet to the reverse osmosis membrane; The processing module is used to extract the decay gradient of the pressure of the water to be treated in the reverse osmosis membrane module from the pressure distribution, and to adjust the operating pressure of the water to be treated in the reverse osmosis membrane module according to the decay gradient and the flow rate of the water to be treated, thereby obtaining the critical steady-state pressure difference of the reverse osmosis membrane module to the water to be treated; The processing module is further configured to monitor pressure differences between water inlet and outlet of the reverse osmosis membrane assembly, perform dynamic load analysis on the contaminant load on the reverse osmosis membrane according to the monitored change trend of all the pressure differences and the suspended solid concentration of the water to be treated, and obtain a dynamic deposited contamination layer of the contaminant on the reverse osmosis membrane. The execution module is configured to determine a contaminant deposition flux on the reverse osmosis membrane in the reverse osmosis membrane assembly by using the critical steady-state pressure difference and the dynamic deposited contamination layer, and trigger a cleaning program of the reverse osmosis membrane assembly to clean the contaminant on the reverse osmosis membrane when the contaminant deposition flux exceeds a preset deposition threshold of the contaminant on the reverse osmosis membrane.

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