Membrane fouling backwash method based on orifice blockage evolution and related device

Abstract

The application relates to a membrane pollution backwashing method based on orifice blockage evolution and a related device, and belongs to the technical field of environmental engineering, wherein the membrane pollution backwashing method based on orifice blockage evolution comprises the following steps: obtaining an initial flux of a filter membrane, and collecting real-time filtration operation data in a filtration process of the filter membrane; calculating a stage proportion of the filter membrane in four preset membrane pollution states based on the initial flux and the real-time filtration operation data, wherein the four membrane pollution states include standard blockage, complete blockage, intermediate blockage and filter cake blockage; calculating a flux decline value of the filter membrane based on a real-time flux and the initial flux of the filter membrane, and calculating an orifice blockage evolution state of the filter membrane based on the stage proportion; and when the flux decline value is greater than or equal to a preset decline threshold value or the orifice blockage evolution state reaches a preset backwashing condition, backwashing is performed on the filter membrane. The application can accurately determine a backwashing time of the filter membrane, and guarantees the quality and efficiency of filter membrane backwashing.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering technology, and in particular to a membrane fouling backwashing method and related apparatus based on orifice blockage evolution. Background Technology

[0002] Membrane separation technology has been widely applied in drinking water purification, industrial wastewater treatment, reclaimed water reuse, food and pharmaceutical separation, seawater desalination pretreatment, membrane bioreactors, and ultrapure water preparation in the electronics industry. During continuous operation, membrane systems inevitably experience fouling. Contaminants can form deposits, bridging, blockages, and cake layers on the membrane pores, pore openings, and surface, leading to decreased flux, increased transmembrane pressure, increased energy consumption, and shortened membrane lifespan. Backwashing is one of the most common and critical online cleaning methods in industrial membrane systems. Its timing directly determines the membrane flux recovery effect, operating cycle length, cleaning water consumption, energy consumption, and membrane module lifespan.

[0003] In existing technologies, backwashing timing largely relies on fixed operating time, fixed permeate flow rate, fixed transmembrane pressure threshold, or fixed flux decline rate. While this empirical control method is easy to implement, it has significant limitations. On the one hand, fixed-cycle backwashing may prematurely clean the pollutants before they have fully developed, increasing backwashing water and energy consumption. On the other hand, simply waiting for the flux or transmembrane pressure to reach the threshold may mean missing the optimal cleaning window for the transition of pollutants from a reversible to an irreversible state, leading to a reduced backwash recovery rate. Especially in complex industrial water bodies, the composition of influent organic matter, colloids, proteins, polysaccharides, oils, and inorganic particles varies considerably, and the properties of pollutants and the pollution evolution process differ significantly. A single empirical threshold is insufficient to adapt to different pollution processes.

[0004] It is evident that existing technologies for backwashing filter membranes are not intelligent enough, and cannot achieve more precise, stable, and scalable decisions on when to clean the membranes. Summary of the Invention

[0005] In view of this, it is necessary to provide a membrane fouling backwashing method and related apparatus based on the evolution of pore blockage, so as to solve the problem that the existing technology is not intelligent enough for backwashing the filter membrane and cannot achieve more accurate, stable and scalable membrane cleaning timing decisions.

[0006] To address the aforementioned problems, in a first aspect, the present invention provides a membrane fouling backwashing method based on orifice blockage evolution, comprising: Obtain the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process; The percentage of the filter membrane in four preset membrane fouling states is calculated based on the initial flux and real-time filtration operation data. The four membrane fouling states include standard clogging, complete clogging, intermediate clogging, and cake clogging. The flux decrease of the filter membrane is calculated based on the real-time flux and initial flux. The pore blockage evolution state of the filter membrane is calculated based on the stage ratio. When the flux decrease is greater than or equal to the preset decrease threshold, or when the pore blockage evolution state reaches the preset backwashing condition, the filter membrane is backwashed.

[0007] In one possible implementation, obtaining the initial flux of the filter membrane includes: The average flux after the first use of the filter membrane or after backwashing for an initial preset time is used as the initial flux of the filter membrane; Alternatively, the median flux at each flux collection point after the first use of the filter membrane or after backwashing can be used as the initial flux of the filter membrane. Alternatively, the average flux within the first time window after the filter membrane is used for the first time or after backwashing can be used as the initial flux of the filter membrane.

[0008] In one possible implementation, real-time filtration operation data during the membrane filtration process includes real-time flux, filtration duration, transmembrane pressure difference, feed water quality parameters, membrane module operating status, and backwashing status.

[0009] In one possible implementation, the formula for calculating the percentage of the four membrane fouling states is as follows:

[0010]

[0011]

[0012] in, This represents the percentage of stages in the standard congestion state. This represents the percentage of the stage in a completely blocked state. This represents the percentage of intermediate congestion stages. This represents the percentage of stages where the filter cake becomes clogged. The cumulative effect of standard congestion conditions, The cumulative effect of a completely blocked state, This is the cumulative effect of intermediate blockage. The cumulative effect of filter cake clogging, The cumulative total effect of the four blockage states. and Let these be the start and end times of the current cycle. This represents the initial flux of the filter membrane. The kinetic constants under standard clogging conditions, The kinetic constants for a completely blocked state are: The dynamic constant of the intermediate blockage, The kinetic constant for filter cake clogging is... a This is a weighting parameter for the difference between standard clogging and filter cake clogging. b This is a weighting adjustment parameter between complete blockage and intermediate blockage.

[0013] In one possible implementation, the pore clogging evolution state of the filter membrane includes the intermediate clogging state decay rate, the proportion of intermediate clogging state duration, and the ratio of the proportion of the fully clogging state stage to the proportion of the intermediate clogging state stage. The formula for calculating the intermediate clogging state decay rate is as follows:

[0014] in, The decay rate during intermediate blockage states. This is the baseline value for intermediate clogging in the current filtration cycle. This represents the percentage of intermediate blockage states in the current filtration cycle. The formula for calculating the percentage of time spent in intermediate congestion is as follows:

[0015] in, This represents the percentage of time the intermediate blockage lasts. This refers to the cumulative duration during which the proportion of intermediate congestion states within the observation period reaches the effective identification threshold. The length of the observation time window; The formula for calculating the ratio of the completely blocked state stage to the intermediate blocked state stage is as follows:

[0016] in, This represents the ratio of the percentage of the completely blocked state to the percentage of the intermediate blocked state. This represents the percentage of the current filtration cycle that is in a completely clogged state. This is a safety constant.

[0017] In one possible implementation, the preset rinsing conditions include at least one of the following: The attenuation rate in the intermediate blockage state is greater than or equal to the preset attenuation rate threshold; The duration of intermediate blockage is greater than or equal to a preset cumulative duration threshold. The ratio of the percentage of the completely blocked state stage to the percentage of the intermediate blocked state stage is greater than the preset ratio threshold.

[0018] In one possible implementation, after backwashing the filter membrane, the process includes: The flux recovery rate of the filter membrane is calculated based on the stable flux before and after backwashing. When the flux recovery rate after multiple backwashes is lower than the preset flux recovery rate threshold, the backwash trigger threshold is adjusted. The backwash trigger threshold includes the decay rate threshold, the cumulative duration threshold, the ratio threshold, the flux decrease threshold, and the observation time window length.

[0019] Secondly, the present invention also provides a membrane fouling backwashing device based on orifice blockage evolution, comprising: The status acquisition module is used to obtain the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process. The clogging status identification module is used to calculate the percentage of the filter membrane in four preset membrane fouling states based on the initial flux and real-time filtration operation data. The four membrane fouling states include standard clogging, complete clogging, intermediate clogging, and cake clogging. The backwashing module is used to calculate the flux decrease of the filter membrane based on the real-time flux and initial flux, calculate the pore blockage evolution state of the filter membrane based on the stage ratio, and backwash the filter membrane when the flux decrease is greater than or equal to the preset decrease threshold, or when the pore blockage evolution state reaches the preset backwashing condition.

[0020] Thirdly, the present invention also provides a membrane fouling backwashing device based on orifice blockage evolution, comprising a data acquisition unit, a memory, a processor, and a backwashing actuator, wherein, The data acquisition unit is used to collect real-time filtration operation data during the filtration process of the filter membrane; Memory, used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the membrane fouling backwashing method based on orifice clogging evolution in any of the above implementations, and to generate backwashing control instructions; The backwashing actuator is used to backwash the filter membrane in response to backwashing control commands.

[0021] Fourthly, the present invention also provides a computer-readable storage medium for storing a computer-readable program or instructions, which, when executed by a processor, can implement the steps in the membrane fouling backwashing method based on orifice blockage evolution as described above.

[0022] The beneficial effects of this invention are as follows: The membrane fouling backwashing method based on pore blockage evolution provided by this invention obtains the initial flux of the filter membrane and collects real-time filtration operation data during the filtration process, providing a data basis for determining the subsequent membrane fouling state. Based on the initial flux and real-time filtration operation data, the method calculates the percentage of the filter membrane in four preset membrane fouling states, including standard blockage, complete blockage, intermediate blockage, and cake blockage. This method fills the gap in existing membrane system backwashing methods that mainly rely on fixed time, fixed flux, fixed transmembrane pressure difference, or other empirical rules for cleaning intervention. Based on the real-time flux and initial flux of the filter membrane, the method calculates the flux decrease value of the filter membrane, and calculates the pore blockage evolution state of the filter membrane based on the percentage of stages. When the flux decrease value is greater than or equal to a preset decrease threshold, or when the pore blockage evolution state reaches the preset backwashing conditions, the filter membrane is backwashed. Introducing information on the evolution of membrane pore blockage structure into backwashing decisions can identify critical windows where contamination transitions from a reversible to an irreversible state. By using a decision rule that prioritizes the fulfillment of multiple conditions, it takes into account both changes in contamination mechanisms and macroscopic flux safety boundaries. This can reduce water and energy consumption caused by premature backwashing and avoid irreversible contamination accumulation caused by late backwashing, ensuring the correct timing of backwashing and improving backwashing efficiency. Attached Figure Description

[0023] 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.

[0024] Figure 1 A schematic flowchart of a membrane fouling backwashing method based on orifice blockage evolution provided in an embodiment of the present invention; Figure 2 A schematic flowchart of a backwashing post-treatment method provided in an embodiment of the present invention; Figure 3 A block diagram illustrating the principle of membrane fouling backwashing provided in an embodiment of the present invention; Figure 4 A backwashing intervention point analysis diagram for a membrane fouling filtration process provided in an embodiment of the present invention; Figure 5 A schematic diagram of a membrane fouling backwashing device based on orifice blockage evolution provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of a membrane fouling backwashing device based on orifice blockage evolution, provided as an embodiment of the present invention. Detailed Implementation

[0025] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0026] In the description of the embodiments of the present invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0027] The terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] A specific embodiment of the present invention, such as Figure 1 As shown, a membrane fouling backwashing method based on orifice clogging evolution is disclosed, comprising: S101, obtain the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process.

[0030] In this embodiment of the invention, the filter membrane can be a pressure-driven membrane such as an ultrafiltration membrane, microfiltration membrane, nanofiltration membrane, or reverse osmosis membrane. Initial flux refers to the amount of permeate passing through the membrane per unit time and per unit area under standard operating conditions when the filter membrane is in a clean state or at the start of a filtration cycle. Initial flux can be reacquired after each backwash or measured before the membrane system is put into operation. During filtration, the permeate flow rate is collected in real time by a flow meter installed on the permeate pipeline of the membrane module; the transmembrane pressure difference is collected in real time by pressure sensors installed on the feed side and permeate side of the membrane; the feed water turbidity is collected by an online turbidity meter; and the feed water temperature is collected by a temperature sensor. The data acquisition module records real-time filtration operation data according to a preset sampling period, such as every thirty seconds or every two minutes. The real-time flux is calculated based on the permeate flow rate and the effective membrane area and normalized to standard pressure and temperature conditions to eliminate the influence of fluctuations in operating conditions.

[0031] S102, calculates the percentage of the filter membrane in four preset membrane fouling states based on the initial flux and real-time filtration operation data. The four membrane fouling states include standard clogging, complete clogging, intermediate clogging, and cake clogging.

[0032] In this embodiment of the invention, four membrane fouling states are defined as standard clogging, complete clogging, intermediate clogging, and cake clogging. These four states reflect different mechanisms of membrane fouling. Standard clogging refers to contaminant particles smaller than the membrane pore size entering the pores and adhering to the pore walls, narrowing the membrane channels and gradually increasing filtration resistance. Complete clogging refers to contaminant particles with a size equal to or slightly larger than the membrane pore size, completely blocking a single membrane pore and causing that pore to lose its filtration capacity. Intermediate clogging refers to particles partially covering the membrane pore, or multiple particles overlapping and bridging near the pore, forming incomplete clogging, with a degree of clogging between complete and standard clogging. Cake clogging refers to contaminants depositing layer by layer on the membrane surface, forming a cake layer covering the membrane surface, which itself generates additional filtration resistance. Stage percentage is used to characterize the relative proportion of each of the four fouling states in the current total membrane fouling. Stage percentage can be obtained by analyzing real-time filtration operation data. For example, during membrane filtration, as fouling develops, the curve of normalized flux changing with operating time exhibits different characteristics under different fouling mechanisms. Standard clogging-dominated fouling typically manifests as a slow decrease in flux with a gradually slowing rate of decline; complete clogging-dominated fouling shows an approximately linear decrease in flux as each orifice is blocked; intermediate clogging-dominated fouling exhibits a flux decline rate between that of standard and complete clogging; cake clogging-dominated fouling shows a flux decline rate correlated with the increase in cake thickness, typically decreasing rapidly in the initial stages of filtration and then gradually leveling off. Reference characteristic curves or characteristic parameter libraries are pre-established for the four fouling states. When calculating the stage proportion, the measured normalized flux change sequence is matched or decomposed with the reference characteristic curves to determine the combination coefficients corresponding to each fouling state; these combination coefficients are the stage proportions. The matching process can be achieved using methods such as minimum deviation fitting, pattern recognition, neural network classification, and support vector machine regression. Since real-time filtration operation data may simultaneously contain contributions from multiple fouling mechanisms, the stage proportions can more comprehensively reflect the true composition of membrane fouling.

[0033] S103, calculate the flux decrease value of the filter membrane based on the real-time flux and initial flux, calculate the pore blockage evolution state of the filter membrane based on the stage ratio, and backwash the filter membrane when the flux decrease value is greater than or equal to the preset decrease threshold, or when the pore blockage evolution state reaches the preset backwashing condition.

[0034] In this embodiment of the invention, the flux decrease value can be obtained by the difference between the initial flux and the real-time flux, or it can be expressed as the percentage of this difference to the initial flux. The decrease threshold is preset based on factors such as membrane type, feed water quality, and target permeate rate. For example, for ultrafiltration membrane treatment of surface water, the decrease threshold can be set to 20% to 30% of the initial flux; for microfiltration membrane treatment of high-turbidity feed liquid, the decrease threshold can be set to 30% to 40% of the initial flux. When the flux decrease value reaches the threshold, it indicates that the membrane filtration resistance has increased significantly, and backwashing needs to be initiated to restore the flux.

[0035] Furthermore, the pore clogging evolution status is calculated based on the stage proportions of the four membrane fouling states, reflecting the degree of pore clogging and its changing trend. The pore clogging evolution status can include a single comprehensive index or multiple sub-indicators. For example, the ratio of complete clogging to intermediate clogging can be used as an indicator of pore clogging degree, as these two states directly represent the degree to which the membrane pores are blocked or partially blocked by particles. The standard clogging percentage can be used as an indicator of pore clogging, as standard clogging indicates that contaminants have entered the membrane pores. The changing trends of the complete and intermediate clogging percentages over multiple consecutive sampling periods can also be used as indicators of pore clogging evolution trend. If the complete and intermediate clogging percentages continue to rise, it indicates that the membrane pores are being blocked by more and more particles. Even if the current flux decline has not yet reached the decline threshold, backwashing should be initiated in advance to prevent contaminants from being further compacted at the pores or entering deeper into the membrane pores. If the standard clogging percentage rises rapidly, it indicates that contaminants are beginning to migrate into the membrane pores. In this case, backwashing should also be initiated as soon as possible, and chemically enhanced backwashing can be used as needed. The preset backwashing conditions can be set according to actual needs, which will be described in detail later in this invention.

[0036] The membrane fouling backwashing method based on pore blockage evolution provided by this invention obtains the initial flux of the filter membrane and collects real-time filtration operation data during the filtration process, providing a data basis for determining the subsequent membrane fouling state. Based on the initial flux and real-time filtration operation data, the method calculates the percentage of the filter membrane in four preset membrane fouling states, including standard blockage, complete blockage, intermediate blockage, and cake blockage. This method addresses the shortcomings of existing membrane system backwashing methods that mainly rely on fixed time, fixed flux, fixed transmembrane pressure difference, or other empirical rules for cleaning intervention. Based on the real-time flux and initial flux of the filter membrane, the method calculates the flux decrease value of the filter membrane and the pore blockage evolution state of the filter membrane based on the percentage of stages. When the flux decrease value is greater than or equal to a preset decrease threshold, or when the pore blockage evolution state reaches a preset backwashing condition, the filter membrane is backwashed. Introducing information on the evolution of membrane pore blockage structure into backwashing decisions can identify critical windows where contamination transitions from a reversible to an irreversible state. By using a decision rule that prioritizes the fulfillment of multiple conditions, it takes into account both changes in contamination mechanisms and macroscopic flux safety boundaries. This can reduce water and energy consumption caused by premature backwashing and avoid irreversible contamination accumulation caused by late backwashing, ensuring the correct timing of backwashing and improving backwashing efficiency.

[0037] In some possible embodiments of the present invention, obtaining the initial flux of the filter membrane includes: The average flux after the first use of the filter membrane or after backwashing for an initial preset time is used as the initial flux of the filter membrane; Alternatively, the median flux at each flux collection point after the first use of the filter membrane or after backwashing can be used as the initial flux of the filter membrane. Alternatively, the average flux within the first time window after the filter membrane is used for the first time or after backwashing can be used as the initial flux of the filter membrane.

[0038] Furthermore, real-time filtration operation data during the filtration process includes real-time flux, filtration duration, transmembrane pressure difference, feed water quality parameters, membrane module operating status, and backwashing status.

[0039] In this embodiment of the invention, an online flow meter, pressure sensor, temperature sensor, and control valve are installed in the membrane filtration system to collect data in real time on permeate flux, filtration time, transmembrane pressure difference, feed water quality parameters, membrane module operating status, and backwashing status. Permeate flux J(t) This can be obtained by converting the permeate flow rate to the effective membrane area:

[0040] in, Q(t) The water production flow rate per unit time. A The effective filtration area of ​​the membrane module. Transmembrane pressure difference. TMP(t)It can be represented as:

[0041] in, Pin(t) For the inlet water pressure of the membrane module, Pout(t) This refers to the pressure on the water production side of the membrane module.

[0042] Influent water quality parameters may include turbidity, total organic carbon, chemical oxygen demand (COD), concentration of protein pollutants, concentration of polysaccharide pollutants, concentration of colloidal particles, particle size distribution, conductivity, temperature, and pH. The flux data sampling interval can be set from 1 to 60 seconds. For laboratory membrane filtration devices, a sampling interval of 1-10 seconds is preferred; for industrial membrane treatment systems, a sampling interval of 5-60 seconds is preferred. To reduce measurement noise, flux data can be processed using moving average, median filtering, exponential smoothing, or robust fitting.

[0043] After each backwash and filtration is resumed, the system enters a new filtration cycle. The system selects the average flux during the initial stable operation after backwashing as the initial flux for the current filtration cycle. Specifically, one of the following methods can be used: Take the average flux within 1-3 minutes after backwashing; take the median of multiple consecutive data points after backwashing; when the flux variation coefficient is below 5%-10%, take the average flux of the corresponding time window as J0; take the flux of the first time window after backwashing when the system reaches a steady state. The flux retention rate within the current filtration cycle is:

[0044] At the same time, an intermediate blockage observation window is set at the beginning of the filtration cycle. This observation window can be the first 5%-20% of the entire filtration process, or it can be determined based on the stage when the intermediate blockage percentage first reaches its peak or stabilizes.

[0045] Within this observation window, calculate the average, median, or maximum percentage of intermediate congestion as the baseline value for intermediate congestion. .

[0046] In some possible embodiments of the present invention, the formula for calculating the percentage of the four membrane fouling states is as follows:

[0047]

[0048]

[0049] in, This represents the percentage of stages in the standard congestion state. This represents the percentage of the stage in a completely blocked state. This represents the percentage of intermediate congestion stages. This represents the percentage of stages where the filter cake becomes clogged. The cumulative effect of standard congestion conditions, The cumulative effect of a completely blocked state, This is the cumulative effect of intermediate blockage. The cumulative effect of filter cake clogging, The cumulative total effect of the four blockage states. and Let these be the start and end times of the current cycle. This represents the initial flux of the filter membrane. The kinetic constants under standard clogging conditions, The kinetic constants for a completely blocked state are: The dynamic constant of the intermediate blockage, The kinetic constant for filter cake clogging is... a This is a weighting parameter for the difference between standard clogging and filter cake clogging. b This is a weighting adjustment parameter between complete blockage and intermediate blockage.

[0050] In this embodiment of the invention, under constant pressure filtration conditions, flux decline is jointly determined by changes in membrane resistance and changes in effective filtration area. Standard clogging and cake clogging primarily reflect changes in membrane resistance, while complete clogging and intermediate clogging primarily reflect changes in effective filtration area.

[0051] The flux expression after unifying the four congestion mechanisms is:

[0052] The model parameters are optimized with the goal of minimizing the error between the measured flux curve and the model-predicted flux curve.

[0053] The error function L can be expressed as:

[0054] in, Let be the measured flux at the q-th sampling time. To predict flux for the model, n This represents the number of sampling points. Normalized root mean square error or mean absolute percentage error can also be used as model evaluation metrics.

[0055] After obtaining the model parameters, the preset time window [ , The cumulative effect of the four blocking mechanisms within the system is calculated using the formula above.

[0056] In some possible embodiments of the present invention, the pore blockage evolution state of the filter membrane includes the intermediate blockage state decay rate, the proportion of intermediate blockage state duration, and the ratio of the proportion of the completely blocked state stage to the proportion of the intermediate blockage state stage. The formula for calculating the intermediate blockage state decay rate is as follows:

[0057] in, The decay rate during intermediate blockage states. This is the baseline value for intermediate clogging in the current filtration cycle. This represents the percentage of intermediate blockage states in the current filtration cycle. The formula for calculating the percentage of time spent in intermediate congestion is as follows:

[0058] in, This represents the percentage of time the intermediate blockage lasts. This refers to the cumulative duration during which the proportion of intermediate congestion states within the observation period reaches the effective identification threshold. The length of the observation time window; The formula for calculating the ratio of the completely blocked state stage to the intermediate blocked state stage is as follows:

[0059] in, This represents the ratio of the percentage of the completely blocked state to the percentage of the intermediate blocked state. This represents the percentage of the current filtration cycle that is in a completely clogged state. This is a safety constant.

[0060] In this embodiment of the invention, the following orifice blockage evolution signals are extracted: current intermediate blockage percentage; current complete blockage percentage; intermediate blockage attenuation rate; complete blockage / intermediate blockage ratio; and intermediate blockage duration percentage.

[0061] In this embodiment of the invention, the preset rinsing conditions include at least one of the following: The attenuation rate in the intermediate blockage state is greater than or equal to the preset attenuation rate threshold; The duration of intermediate blockage is greater than or equal to a preset cumulative duration threshold. The ratio of the percentage of the completely blocked state stage to the percentage of the intermediate blocked state stage is greater than the preset ratio threshold.

[0062] Specifically, set a flux-driven forced cleaning threshold. , The range is 0.50-0.70. When: At that time, the backwash command is output directly.

[0063] For example, when When the flux is 0.60, if the current flux drops below 60% of the initial flux, backwashing is performed immediately without waiting for other criterion mechanisms. This condition is used to prevent the membrane system from continuing to operate under severe fouling conditions and is the mandatory safety boundary of this invention.

[0064] The current flux has not yet reached the mandatory cleaning threshold, i.e. Continue monitoring the intermediate congestion attenuation rate. Set an intermediate congestion attenuation threshold. , The range is 0.20-0.30. When: At that time, output backwash control command.

[0065] For example, when When the value is 0.30, if the current proportion of intermediate blockage decreases by more than 30% relative to the baseline value, it is determined that the orifice bridging structure has significantly deteriorated, and backflushing is performed in advance.

[0066] Furthermore, the cumulative time that intermediate blockages effectively existed within the current observation period was statistically analyzed. and When the intermediate blockage has undergone the formation, maintenance, and decay processes, backflushing is triggered. This auxiliary criterion is used to reduce the impact of model errors, measurement noise, or short-term fluctuations at a single time point on the backflushing decision.

[0067] Furthermore, when the current flux has not yet reached the forced cleaning threshold, the complete blockage / intermediate blockage ratio is calculated. When the percentage of complete blockage exceeds that of intermediate blockage, the orifice contamination status changes from being dominated by intermediate blockage to being dominated by complete blockage. At this point, a backflushing control command is output to initiate membrane cleaning in advance.

[0068] In this embodiment of the invention, three backwashing control processes are defined. The first control process is flux mandatory control, which requires backwashing when the flux drops to 50%-70% of the initial flux. The second control process is intermediate blockage attenuation monitoring, which triggers backwashing when the flux has not yet reached the mandatory threshold, but the proportion of intermediate blockage decreases by 20%-30% relative to the baseline state, or when the proportion of intermediate blockage duration reaches 50% and then decreases by 20%-30%. The third control process is complete blockage enhancement monitoring, which triggers backwashing when the flux has not yet reached the mandatory threshold, but the ratio of the proportion of complete blockage to the proportion of intermediate blockage is greater than 1. The three control processes are triggered in a first-come, first-served manner. If the flux threshold is met first, backwashing is performed directly; if the intermediate blockage attenuation condition or the complete blockage enhancement condition is met first, backwashing is performed in advance before the flux drops significantly. Specifically, the backwashing operation includes closing the inlet valve or filter permeate valve, opening the backwash valve, starting the backwash pump, starting the air scrubbing unit as needed, performing backwashing at the set backwash pressure and flow rate, maintaining the preset backwash time, closing the backwash pump and backwash valve, and resuming normal filtration. The backwash time can be set from 30 seconds to 5 minutes. The backwash pressure can be set to 0.5-2 times the normal filtration pressure. The backwash flow rate can be set according to the effective area of ​​the membrane module, the membrane material, and the degree of fouling.

[0069] In some possible embodiments of the present invention, such as Figure 2 As shown, after backwashing the filter membrane, the process includes: S201, calculate the flux recovery rate of the filter membrane based on the stable flux before backwashing and the stable flux after backwashing; S202, when the flux recovery rate after multiple backwashes is lower than the preset flux recovery rate threshold, the backwash trigger threshold is adjusted. The backwash trigger threshold includes the attenuation rate threshold, the cumulative duration threshold, the ratio threshold, the flux decrease threshold, and the observation time window length.

[0070] In this embodiment of the invention, after backwashing is completed, the stable flux after backwashing is collected, and the flux before backwashing is recorded. Flux recovery rate. FR It can be represented as:

[0071] in, To stabilize the flux after backwashing, Flux before backwashing The initial flux is recorded. Simultaneously, the backwash trigger type, trigger time, flux before backwash, flux after backwash, intermediate clogging attenuation rate, complete clogging / intermediate clogging ratio, backwash water consumption, backwash energy consumption, flux recovery rate, and initial flux for the next filtration cycle are also recorded.

[0072] Furthermore, after backwashing is complete, the stabilized flux after backwashing is reset to the initial flux for the next filtration cycle. At the same time, the intermediate clogging baseline value is re-determined based on the initial data of the new filtration cycle. If the flux recovery rate is low after backwashing in multiple consecutive filtration cycles, increase the sensitivity to pre-cleaning, for example, by raising the intermediate clogging attenuation threshold. The threshold was adjusted from 0.30 to 0.20; the mandatory flux threshold was changed. Increase the threshold from 0.50 to 0.60; shorten the mechanism identification time window; increase the duration requirement for effective identification of intermediate blockages. If backflushing is too frequent and the flux recovery rate does not change significantly, the premature trigger sensitivity can be appropriately reduced.

[0073] Furthermore, such as Figure 3 As shown, this invention addresses the shortcomings of existing membrane system backwashing methods that primarily rely on fixed times, fixed fluxes, fixed transmembrane pressure differentials, or other empirical rules. By incorporating information on the evolution of membrane pore blockage structure into backwashing decisions, it can identify critical windows where fouling transitions from a reversible to an irreversible state. Through the reduction of intermediate blockage percentage and the enhancement of complete blockage percentage, early cleaning intervention before a significant flux decline is achieved. A mandatory cleaning boundary is maintained at 50%-70% of the initial flux, meeting the operational safety requirements of industrial membrane systems. A decision rule that prioritizes the fulfillment of multiple conditions balances changes in fouling mechanisms and macroscopic flux safety boundaries. This reduces water and energy consumption caused by premature backwashing and avoids irreversible fouling accumulation caused by delayed backwashing. It improves flux recovery rates after backwashing and extends the operating cycle and lifespan of membrane modules. It can be applied to industrial membrane filtration scenarios such as drinking water treatment, industrial wastewater reuse, membrane bioreactors, seawater desalination pretreatment, food and pharmaceutical separation, and electronic industry water treatment.

[0074] Furthermore, such as Figure 4 The diagram shown illustrates the backwash intervention point analysis for the membrane fouling filtration process. Here, ObservedFlux represents the observed flux, Full-Process Fitting represents the full-process fitting, Flux-Threshold WindowFitting (70% J0) represents the flux threshold window fitting, Forced 70% Initial Flux Reference represents the forced 70% initial flux reference value, Forced Flux-Threshold Deadline represents the forced flux threshold deadline, and Recommended Industrial Backwash Point 0-25% Tdata Stage represents the recommended industrial backwash point 0-25% Tdata stage. Figure 4It can be seen that the membrane fouling backwashing method based on orifice blockage evolution provided in the embodiments of the present invention is accurate in determining the backwashing point.

[0075] To better implement the membrane fouling backwashing method based on orifice clogging evolution in the embodiments of the present invention, based on the membrane fouling backwashing method based on orifice clogging evolution, correspondingly, as follows: Figure 5 As shown, this embodiment of the invention also provides a membrane fouling backwashing device based on orifice clogging evolution. The membrane fouling backwashing device 500 based on orifice clogging evolution includes: The status acquisition module 501 is used to acquire the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process. The clogging status identification module 502 is used to calculate the percentage of the filter membrane in four preset membrane fouling states based on the initial flux and real-time filtration operation data. The four membrane fouling states include standard clogging, complete clogging, intermediate clogging, and filter cake clogging. The backwashing module 503 is used to calculate the flux decrease value of the filter membrane based on the real-time flux and initial flux, calculate the pore blockage evolution state of the filter membrane based on the stage ratio, and backwash the filter membrane when the flux decrease value is greater than or equal to the preset decrease threshold, or when the pore blockage evolution state reaches the preset backwashing condition.

[0076] The membrane fouling backwashing device 500 based on orifice blockage evolution provided in the above embodiments can realize the technical solutions described in the above embodiments of the membrane fouling backwashing method based on orifice blockage evolution. The specific implementation principles of each module or unit can be found in the corresponding content in the above embodiments of the membrane fouling backwashing method based on orifice blockage evolution, and will not be repeated here.

[0077] like Figure 6 As shown, the present invention also provides a membrane fouling backwashing device 600 based on orifice clogging evolution. This membrane fouling backwashing device 600 includes a processor 601, a memory 602, a data acquisition unit 603, and a backwashing actuator 604. Figure 6 Only a portion of the components of the membrane fouling backwashing device 600 based on orifice clogging evolution are shown; however, it should be understood that implementation of all the components shown is not required, and more or fewer components may be implemented instead.

[0078] In some embodiments, processor 601 may be a central processing unit (CPU), a microprocessor, or other data processing chip, used to run program code stored in memory 602 or process data, such as the membrane fouling backwashing method based on orifice blockage evolution in this invention.

[0079] In some embodiments, processor 601 may be a single server or a group of servers. The server group may be centralized or distributed. In some embodiments, processor 601 may be local or remote. In some embodiments, processor 601 may be implemented on a cloud platform. In some embodiments, the cloud platform may include a private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, internal cloud, multi-cloud, or any combination thereof.

[0080] In some embodiments, memory 602 can be an internal storage unit of the membrane fouling backwashing device 600 based on orifice clogging evolution, such as a hard disk or memory of the membrane fouling backwashing device 600 based on orifice clogging evolution. In other embodiments, memory 602 can also be an external storage device of the membrane fouling backwashing device 600 based on orifice clogging evolution, such as a pluggable hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on the membrane fouling backwashing device 600 based on orifice clogging evolution.

[0081] Furthermore, the memory 602 may include both internal storage units and external storage devices for the membrane fouling backwashing device 600 based on orifice clogging evolution. The memory 602 is used to store application software and various data for installing the membrane fouling backwashing device 600 based on orifice clogging evolution.

[0082] The data acquisition unit 603 can be various sensors installed in the filtration system, such as flow meters, thermometers, water quality meters, etc.

[0083] The backwashing actuator can be a water valve, water pump, air pump, etc.

[0084] In some embodiments, when the processor 601 executes the membrane fouling backwashing program in the memory 602, the following steps may be performed: Obtain the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process; The percentage of the filter membrane in four preset membrane fouling states is calculated based on the initial flux and real-time filtration operation data. The four membrane fouling states include standard clogging, complete clogging, intermediate clogging, and cake clogging. The flux decrease of the filter membrane is calculated based on the real-time flux and initial flux. The pore blockage evolution state of the filter membrane is calculated based on the stage ratio. When the flux decrease is greater than or equal to the preset decrease threshold, or when the pore blockage evolution state reaches the preset backwashing condition, the filter membrane is backwashed.

[0085] It should be understood that when the processor 601 executes the membrane fouling backwashing program in the memory 602, in addition to the functions mentioned above, it can also perform other functions, as detailed in the description of the corresponding method embodiments above.

[0086] Accordingly, this application also provides a computer-readable storage medium for storing a computer-readable program or instruction. When the program or instruction is executed by a processor, it can implement the steps or functions of the membrane fouling backwashing method based on orifice blockage evolution provided in the above-described method embodiments.

[0087] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0088] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A membrane fouling backwashing method based on orifice clogging evolution, characterized in that, include: Obtain the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process of the filter membrane; Based on the initial flux and the real-time filtration operation data, the percentage of the filter membrane in four preset membrane fouling states is calculated, wherein the four membrane fouling states include standard clogging, complete clogging, intermediate clogging, and cake clogging. The flux decrease of the filter membrane is calculated based on the real-time flux and the initial flux. The pore blockage evolution state of the filter membrane is calculated based on the stage percentage. When the flux decrease is greater than or equal to a preset decrease threshold, or when the pore blockage evolution state reaches a preset backwashing condition, the filter membrane is backwashed.

2. The membrane fouling backwashing method based on orifice clogging evolution according to claim 1, characterized in that, The process of obtaining the initial flux of the filter membrane includes: The average flux of the filter membrane after its first use or after backwashing is taken as the initial flux of the filter membrane. Alternatively, the median flux at each flux collection point after the first use of the filter membrane or after backwashing can be used as the initial flux of the filter membrane. Alternatively, the average flux within the first time window after the filter membrane is first used or after backwashing is used to reach a stable state can be used as the initial flux of the filter membrane.

3. The membrane fouling backwashing method based on orifice clogging evolution according to claim 1, characterized in that, The real-time filtration operation data during the filtration process of the filtration membrane includes real-time flux, filtration time, transmembrane pressure difference, influent water quality parameters, membrane module operating status, and backwashing status.

4. The membrane fouling backwashing method based on orifice clogging evolution according to claim 3, characterized in that, The formula for calculating the percentage of the four membrane fouling states is as follows: in, This represents the percentage of stages in the standard congestion state. This represents the percentage of the stage in a completely blocked state. This represents the percentage of intermediate congestion stages. This represents the percentage of stages where the filter cake becomes clogged. The cumulative effect of standard congestion conditions, The cumulative effect of a completely blocked state, This is the cumulative effect of intermediate blockage. The cumulative effect of filter cake clogging, The cumulative total effect of the four blockage states. and Let these be the start and end times of the current cycle. The initial flux of the filter membrane. The kinetic constants under standard clogging conditions, The kinetic constants for a completely blocked state are: The dynamic constant of the intermediate blockage, The kinetic constant for filter cake clogging is... a This is a weighting parameter for the difference between standard clogging and filter cake clogging. b This is a weighting adjustment parameter between complete blockage and intermediate blockage.

5. The membrane fouling backwashing method based on orifice clogging evolution according to claim 4, characterized in that, The pore clogging evolution state of the filter membrane includes the attenuation rate of intermediate clogging state, the proportion of intermediate clogging state duration, and the ratio of the proportion of the completely clogging state stage to the proportion of the intermediate clogging state stage. The formula for calculating the attenuation rate of intermediate clogging state is as follows: in, The decay rate during intermediate blockage states. This is the baseline value for intermediate clogging in the current filtration cycle. This represents the percentage of intermediate blockage states in the current filtration cycle. The formula for calculating the percentage of the duration of the intermediate blockage state is as follows: in, This represents the percentage of time the intermediate blockage lasts. This refers to the cumulative duration during which the proportion of intermediate congestion states within the observation period reaches the effective identification threshold. The length of the observation time window; The formula for calculating the ratio of the percentage of the completely blocked state stage to the percentage of the intermediate blocked state stage is as follows: in, This represents the ratio of the percentage of the completely blocked state to the percentage of the intermediate blocked state. This represents the percentage of the current filtration cycle that is in a completely clogged state. This is a safety constant.

6. The membrane fouling backwashing method based on orifice clogging evolution according to claim 5, characterized in that, The preset rinsing conditions include at least one of the following: The attenuation rate of the intermediate blockage state is greater than or equal to a preset attenuation rate threshold; The duration of the intermediate blockage state is greater than or equal to a preset cumulative duration threshold. The ratio of the percentage of the completely blocked state stage to the percentage of the intermediate blocked state stage is greater than a preset ratio threshold.

7. The membrane fouling backwashing method based on orifice clogging evolution according to claim 1, characterized in that, After backwashing the filter membrane, the process includes: The flux recovery rate of the filter membrane is calculated based on the stable flux before backwashing and the stable flux after backwashing. When the flux recovery rate after multiple backwashes is lower than the preset flux recovery rate threshold, the backwash trigger threshold is adjusted. The backwash trigger threshold includes the attenuation rate threshold, the cumulative duration threshold, the ratio threshold, the flux decrease threshold, and the observation time window length.

8. A membrane fouling backwashing device based on orifice clogging evolution, characterized in that, include: The status acquisition module is used to obtain the initial flux of the filter membrane and collect real-time filtration operation data during the filtration process of the filter membrane. The clogging status identification module is used to calculate the percentage of the filter membrane in four preset membrane fouling states based on the initial flux and the real-time filtration operation data, wherein the four membrane fouling states include standard clogging, complete clogging, intermediate clogging and filter cake clogging. The backwashing module is used to calculate the flux decrease value of the filter membrane based on the real-time flux and the initial flux, calculate the pore blockage evolution state of the filter membrane based on the stage ratio, and backwash the filter membrane when the flux decrease value is greater than or equal to a preset decrease threshold, or when the pore blockage evolution state reaches a preset backwashing condition.

9. A membrane fouling backwashing device based on orifice clogging evolution, characterized in that, It includes a data acquisition unit, a memory, a processor, and a backwashing actuator, among which, The data acquisition device is used to collect real-time filtration operation data during the filtration process of the filter membrane; The memory is used to store programs; The processor, coupled to the memory, is used to execute the program stored in the memory to implement the steps in the membrane fouling backwashing method based on orifice blockage evolution as described in any one of claims 1 to 7, and to generate backwashing control instructions; The backwashing execution structure is used to backwash the filter membrane in response to the backwashing control command.

10. A computer-readable storage medium, characterized in that, Used to store computer-readable programs or instructions, which, when executed by a processor, enable the implementation of the steps in the membrane fouling backwashing method based on orifice blockage evolution as described in any one of claims 1 to 7.

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