A demineralized water treatment system based on pressure feedback regulation

Abstract

This invention relates to the field of demineralized water treatment technology, specifically a demineralized water treatment system based on pressure feedback regulation. It includes an ultrafiltration subsystem, a reverse osmosis subsystem, a mixed-bed subsystem, and a scheduling and coordination module. The ultrafiltration subsystem includes an ultrafiltration sensing module and an ultrafiltration regulation module; the reverse osmosis subsystem includes a reverse osmosis sensing module and a reverse osmosis regulation module; and the mixed-bed subsystem includes a mixed-bed sensing module and a mixed-bed regulation module. This invention solves the problem that the regeneration cycle of various devices often cannot achieve process coordination, leading to discontinuous regeneration processes requiring shutdowns and affecting the system's continuous water production capacity. A PID feedback regulation mechanism is established through data extraction and processing, realizing negative feedback regulation of parameters of various devices in the production process. A rapid response and adjustment composite control model is established to dynamically regulate the dosage of control reagents and the water pressure of the circulating pump.

Description

Technical Field

[0001] This invention relates to the field of demineralized water treatment technology, specifically a demineralized water treatment system based on pressure feedback regulation. Background Technology

[0002] Demineralized water is essential for industrial use, and ensuring its quality is crucial for the safe operation of industrial production. The safe and efficient operation of the demineralized water system is a reliable guarantee for water treatment plant production. Currently, my country's demineralized water production systems mainly consist of two types: reverse osmosis (RO) systems with mixed beds and RO systems with EDI (electrodeionization). The majority use the RO + mixed bed technology, with the main process being: raw water → raw water pressurization pump → self-cleaning filter → ultrafiltration unit → precision filter → reverse osmosis unit → mixed bed → effluent. Ultrafiltration technology is a membrane separation technology that has developed in recent years based on materials science. It has been widely applied in the treatment of industrial wastewater in power, steel, and chemical industries. Current research on ultrafiltration devices focuses on improving membrane permeate production and reducing costs. The patent "Method and Equipment for Constant Flow Ultrafiltration" from the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, primarily achieves the effects of reducing membrane filtration resistance, extending the backwashing cycle, simplifying operation procedures, and increasing membrane permeate production by adjusting the opening mode of the circulating pump. Reverse osmosis (RO) technology utilizes the filtration principle of reverse osmosis membranes. Pressure drives the membrane to separate the solvent from the solution, effectively removing salt ions and most organic matter from the water, ensuring that the effluent quality meets national standards and the actual production needs of enterprises. After long-term development, the membrane flux of reverse osmosis membranes in my country has increased several times, and the most advanced reverse osmosis desalination rates have reached over 99%. Mixed bed osmosis technology operates on the principle of ion exchange and is a commonly used desalination process. It produces stable effluent quality, requires simple pretreatment, and is now widely used in my country's industrial water treatment sector.

[0003] However, existing demineralized water treatment technologies still have many shortcomings and limitations. For example, the production process of demineralized water treatment systems often involves multiple regeneration and recycling processes. In the regeneration cycle of various equipment, process coordination is often not achieved, which leads to the regeneration process not being able to proceed continuously and requires shutdown operation, thus affecting the continuous water production capacity of the system.

[0004] Secondly, existing demineralized water treatment systems involve parameter adjustments for various valves and devices, making operation relatively complex and requiring high skill levels from operators. In actual production, the adjustment and setting of many parameters require judgment based on human experience. There is no established composite control model for rapid response and adjustment, nor a negative feedback system to address the challenges of optimizing the control of reagent dosage and circulating pump water pressure.

[0005] Therefore, it is necessary to propose a demineralized water treatment system based on pressure feedback regulation to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the background art, and to propose a demineralized water treatment system based on pressure feedback regulation;

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A demineralized water treatment system based on pressure feedback regulation includes an ultrafiltration subsystem, a reverse osmosis subsystem, a mixed bed subsystem, and a scheduling and coordination module. The ultrafiltration subsystem includes an ultrafiltration sensing module and an ultrafiltration regulation module; the reverse osmosis subsystem includes a reverse osmosis sensing module and a reverse osmosis regulation module; and the mixed bed subsystem includes a mixed bed sensing module and a mixed bed regulation module.

[0009] The ultrafiltration sensing module acquires the temperature T of the plate heat exchanger, the liquid level C1 in the ultrafiltration water tank, and the pressure P in the ultrafiltration backwash pump at preset time intervals t.

[0010] The reverse osmosis sensing module acquires the influent flow rate Q1 of the precision filter, the liquid level C2 in the freshwater tank, and the conductivity ρ at preset time intervals t.

[0011] The mixed-bed sensing module acquires the conductivity ρ1 of the water entering the mixed ion exchanger at preset time intervals t, and outputs the conductivity ρ2 of the water entering the mixed ion exchanger and the flow rate Q2 of the demineralized water flowing into the demineralized water tank. The difference in conductivity Δρ between the water entering and exiting the mixed ion exchanger is calculated using the formula Δρ=ρ2-ρ1.

[0012] As a preferred embodiment of the present invention, the ultrafiltration sensing module, the reverse osmosis sensing module, and the mixed bed sensing module generate two-dimensional data images about eight sets of time based on the collected data, including temperature-time graph, liquid level-time graph, pressure-time graph, flow rate-time graph, liquid level-time graph, conductivity-time graph, conductivity difference-time graph, and demineralized water flow rate-time graph.

[0013] Furthermore, for the eight sets of images, the cumulative deviation, relative deviation, and deviation change rate of each data point are obtained through data extraction and calculation.

[0014] The data extraction and processing process is as follows:

[0015] Retrieve the preset data fluctuation range limits corresponding to each group of images, including the upper limit XMax and the lower limit XMin; obtain the area of ​​the part above the upper limit of data fluctuation in the eight groups of images respectively, and record it as the cumulative deviation positive value; obtain the area of ​​the part below the lower limit of data fluctuation in the eight groups of images respectively, and record it as the cumulative deviation negative value; record the difference between the cumulative deviation positive value and the cumulative deviation negative value as the cumulative deviation e1(X).

[0016] For the temperature data point (t, X) acquired within the previous preset time interval t, the formula is used to... Calculate the relative deviation e2(X) for each image; using the formula Calculate the deviation change rate e3(X) for each image, where X = T, C1, P, Q1, C2, ρ, Q2 and Δρ.

[0017] In a preferred embodiment of the present invention, control parameters δ1, δ2, δ3, δ4, δ5, δ6, δ7, and δ8 are obtained by data fusion of the cumulative deviation, relative deviation, and deviation change rate extracted from each image. The data fusion process is specifically as follows:

[0018] Through formula Calculate the control parameters δ1, δ2, and δ3;

[0019] Through formula Calculate the control parameters δ4, δ5, and δ6;

[0020] Through formula Calculate the control parameters δ7 and δ8, where λ1, λ2 and λ3 are preset weighting factors.

[0021] In a preferred embodiment of the present invention, the mapped control parameters are obtained through normalization processing, including mapped control parameter one f(δ1), mapped control parameter two f(δ2), mapped control parameter three f(δ3), mapped control parameter four f(δ4), mapped control parameter five f(δ5), mapped control parameter six f(δ6), mapped control parameter seven f(δ7), and mapped control parameter eight f(δ8). The specific process is as follows:

[0022] For the obtained control parameters δ1, δ2, and δ3, their specific values ​​are mapped to the range of -3 to 3. The mapping function is as follows: , where int is the floor function, for example int(2.6) = 2; where δ1Max, δ2Max, and δ3Max are the upper limits of the fluctuation of control parameters δ1, δ2, and δ3, respectively; where δ1Min, δ2Min, and δ3Min are the lower limits of the fluctuation of control parameters δ1, δ2, and δ3, respectively.

[0023] For the obtained control parameters δ4, δ5, and δ6, their specific values ​​are mapped to the range of 0 to 100. The mapping function is as follows: δ4Max, δ5Max, and δ6Max are the upper limits of the fluctuation of control parameters δ4, δ5, and δ6, respectively; δ4Min, δ5Min, and δ6Min are the lower limits of the fluctuation of control parameters δ4, δ5, and δ6, respectively.

[0024] For control parameters δ7 and δ8, their specific values ​​are mapped to the range of -3 to 3. The mapping function is as follows: δ7Max and δ8Max are the upper limits of the fluctuation of control parameters δ7 and δ8, respectively; δ7Min and δ8Min are the lower limits of the fluctuation of control parameters δ7 and δ8, respectively.

[0025] In a preferred embodiment of the present invention, the ultrafiltration adjustment module, the reverse osmosis adjustment module, and the mixed bed adjustment module perform numerical judgment, data fusion, and targeted data execution based on the mapped control parameters, specifically as follows:

[0026] In ultrafiltration systems:

[0027] The ultrafiltration control module performs numerical judgment on the mapped control parameter 1 f (δ1) and control parameter 2 f (δ2) to generate valve opening command parameter ε1; it performs data fusion on the mapped control parameter 2 f (δ2) and mapped control parameter 3 f (δ3) to generate backwash command parameter ε2.

[0028] In a preferred embodiment of the present invention, temperature control adjustment is performed based on the generated valve opening command parameter ε1, specifically as follows:

[0029] First, the valve opening command parameter is evaluated using a first numerical judgment to determine if the value of ε1 is greater than the preset threshold of 0. If yes, the second numerical judgment is performed; otherwise, the steam valve is closed and the temperature control adjustment ends.

[0030] In the second numerical judgment, it is determined whether the value of ε1 is greater than or equal to the preset threshold of 5. If so, the steam valve is opened and maintained for 10 seconds. Then, the value of ε1 is decremented by one and the system returns to the second numerical judgment to form a loop. The loop ends when the value of ε1 is negative in the second numerical judgment. If negative, the steam valve is opened and maintained for 10 seconds, then the valve is closed and the temperature control ends.

[0031] In a preferred embodiment of the present invention, the ultrafiltration backwashing operation is performed according to the specific value of the backwashing command parameter ε2, specifically as follows:

[0032] If the value of the backwash command parameter ε2 is greater than or equal to the preset maximum threshold ε2Max, a first backwash command is sent to the ultrafiltration backwash pump. If the value of the backwash command parameter ε2 is less than the maximum threshold ε2Max but greater than or equal to the minimum threshold ε2Min, a second backwash command is sent to the ultrafiltration backwash pump.

[0033] The first backwash command specifically involves: turning on the ultrafiltration backwash pump and starting the pump start-up timer; pumping the ultrafiltration water output from the ultrafiltration device from the ultrafiltration water tank back into the input end of the ultrafiltration device at a preset first head H1 and a first pump shaft speed n1 for ultrafiltration backwashing. When the pump start-up timer reaches the preset first start-up time T1, the ultrafiltration backwash pump is turned off.

[0034] The second backwash command is as follows: The ultrafiltration backwash pump is turned on and a start-up timer is established. The ultrafiltration water output from the ultrafiltration device is pumped back into the input of the ultrafiltration device from the ultrafiltration water tank at a preset second head H2 and second pump shaft speed n2 for ultrafiltration backwashing. When the start-up timer reaches the preset second start-up time T2, the ultrafiltration backwash pump is turned off.

[0035] In terms of specific values, the first head H1 of the ultrafiltration backwash pump is greater than the second head H2; the first pump shaft speed n1 of the ultrafiltration backwash pump is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

[0036] In the reverse osmosis subsystem:

[0037] The reverse osmosis control module obtains the backwash command parameter ε3 through data fusion.

[0038] In a preferred embodiment of the present invention, the reverse osmosis flushing operation is performed according to the specific value of the backwash command parameter ε3, specifically as follows:

[0039] If the value of the backwash command parameter ε3 is greater than or equal to the preset maximum threshold ε3Max, a first backwash command is sent to the reverse osmosis high-pressure flushing pump. If the value of the backwash command parameter ε3 is less than the maximum threshold ε3Max but greater than or equal to the minimum threshold ε3Min, a second backwash command is sent to the reverse osmosis high-pressure flushing pump.

[0040] The first reverse osmosis command specifically involves: turning on the reverse osmosis high-pressure flushing pump and starting the pump start-up timer; pumping freshwater output from the reverse osmosis unit back into the input end of the reverse osmosis unit from the freshwater tank at a preset first head H1 and a first pump shaft speed n1 for reverse osmosis flushing; and turning off the reverse osmosis high-pressure flushing pump when the pump start-up timer reaches the preset first start-up time T1.

[0041] The second reverse osmosis command specifically involves: turning on the reverse osmosis high-pressure flushing pump and starting the pump start-up timer; pumping the freshwater output from the reverse osmosis unit from the freshwater tank back into the input end of the reverse osmosis unit at a preset second head H2 and second pump shaft speed n2 for reverse osmosis flushing. When the pump start-up timer reaches the preset second start-up time T2, the reverse osmosis high-pressure flushing pump is turned off.

[0042] In terms of specific values, the first head H1 is greater than the second head H2; the first pump shaft speed n1 is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

[0043] In a preferred embodiment of the present invention, the dosage of the dosing system is optimized and adjusted according to the control parameter δ6 corresponding to the conductivity, specifically as follows:

[0044] The normalized control parameter f(δ6) is numerically fuzzified using the formula. Calculate the dosing execution parameter ε4, where A is a preset conductivity model constant, B is a preset flux constant, and ε4Max is a preset maximum dosage. Adjust the dosing dose to ε4 at preset time intervals t.

[0045] In a mixed-bed subsystem:

[0046] The mixed bed adjustment module performs numerical judgment on the normalized control parameters f(δ7) and f(δ8) to generate the regeneration command parameter ε5.

[0047] The freshwater pump is switched on and off according to the specific value of the regeneration command parameter ε5, specifically as follows:

[0048] If the value of the regeneration command parameter ε5 is greater than or equal to the preset maximum threshold ε5Max, a first reverse osmosis command is sent to the freshwater pump. If the value of the regeneration command parameter ε5 is less than the maximum threshold ε5Max but greater than or equal to the minimum threshold ε5Min, a second reverse osmosis command is sent to the freshwater pump.

[0049] The first reverse osmosis command specifically involves: turning on the freshwater pump and starting the pump start-up timer; pumping freshwater output from the reverse osmosis unit from the freshwater tank back into the input end of the reverse osmosis unit at a preset first head H1 and a first pump shaft speed n1 for reverse osmosis flushing; and turning off the freshwater pump when the pump start-up timer reaches the preset first start-up time T1.

[0050] The second reverse osmosis command specifically involves: turning on the freshwater pump and starting the pump start-up timer; pumping the freshwater output from the reverse osmosis unit back into the input end of the reverse osmosis unit from the freshwater tank at a preset second head H2 and second pump shaft speed n2 for reverse osmosis flushing. When the pump start-up timer reaches the preset second start-up time T2, the freshwater pump is turned off.

[0051] In terms of specific values, the first head H1 is greater than the second head H2; the first pump shaft speed n1 is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

[0052] In a preferred embodiment of the present invention, the scheduling and coordination module achieves process coordination and error control of the ultrafiltration subsystem, reverse osmosis subsystem, and mixed bed subsystem through pump parameter adjustment, specifically as follows:

[0053] Control parameter δ2 is obtained from the ultrafiltration subsystem; control parameters δ4 and δ5 are obtained from the reverse osmosis subsystem; and control parameter δ8 is obtained from the mixed bed subsystem.

[0054] Through formula Calculate the overall equilibrium factor S(1,2,3). Where S(1,2) is the equilibrium factor of the ultrafiltration subsystem and the reverse osmosis subsystem; and S(2,3) is the equilibrium factor of the reverse osmosis subsystem and the mixed bed subsystem.

[0055] When the overall balance factor S(1,2,3) is greater than the preset threshold S(1,2,3)MAX, the balance factors S(1,2) and S(2,3) are numerically evaluated. The specific process is as follows:

[0056] If the value of the balance factor S(1,2) is greater than the preset threshold S(1,2)Max, increase the first head and the first pump shaft speed of the ultrafiltration backwash pump.

[0057] If the value of the balance factor S(2,3) is greater than the preset threshold S(2,3)Max, increase the first head and the first pump shaft speed of the reverse osmosis high-pressure flushing pump.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] In the regeneration cycle of various devices, process coordination is often not achieved, which leads to the regeneration process being unable to proceed continuously, requiring shutdown operations and affecting the system's continuous water production capacity.

[0060] Secondly, existing demineralized water treatment systems involve parameter adjustments for various valves and devices, making operation relatively complex and requiring high skill levels from operators. In actual production, the adjustment and setting of many parameters require judgment based on human experience. There is no established composite control model for rapid response and adjustment, nor a negative feedback system to address the challenges of optimizing the control of reagent dosage and circulating pump water pressure.

[0061] (1) This invention achieves process coordination and error control of the ultrafiltration subsystem, reverse osmosis subsystem and mixed bed subsystem through the scheduling and coordination module by adjusting the water pump parameters. This solves the problem that process coordination is often not achieved in the regeneration cycle of each device, which leads to the regeneration process not being able to proceed continuously and requires shutdown operation, thus affecting the continuous water production capacity of the system.

[0062] (2) This invention establishes a PID feedback regulation mechanism through data extraction and processing of the ultrafiltration sensing module, reverse osmosis sensing module and mixed bed sensing module, realizing negative feedback regulation of parameters of each device in the production process; and establishes a composite control model with fast response and adjustment to dynamically regulate the dosage of control reagents and the water pressure of the circulating pump. Attached Figure Description

[0063] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings:

[0064] Figure 1 This is a flowchart of the method of the present invention;

[0065] Figure 2 This is a schematic diagram of the data images of the present invention;

[0066] Figure 3 This is a schematic diagram of the temperature control process of the present invention;

[0067] Figure 4 This is a schematic diagram of the scheduling and coordination of the present invention. Detailed Implementation

[0068] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] Please see Figure 1 As shown, a demineralized water treatment system based on pressure feedback regulation includes an ultrafiltration subsystem, a reverse osmosis subsystem, a mixed bed subsystem, and a scheduling and coordination module. The ultrafiltration subsystem includes an ultrafiltration sensing module and an ultrafiltration regulation module; the reverse osmosis subsystem includes a reverse osmosis sensing module and a reverse osmosis regulation module; and the mixed bed subsystem includes a mixed bed sensing module and a mixed bed regulation module.

[0070] First embodiment:

[0071] The negative feedback regulation of ultrafiltration backwashing is achieved through PID control of the ultrafiltration subsystem.

[0072] The hardware devices in the ultrafiltration subsystem include a plate heat exchanger, an ultrafiltration unit, an ultrafiltration water tank, and an ultrafiltration backwash pump.

[0073] The ultrafiltration subsystem includes an ultrafiltration sensing module and an ultrafiltration regulation module.

[0074] The ultrafiltration sensing module acquires the temperature T of the plate heat exchanger, the liquid level C1 in the ultrafiltration water tank, and the pressure P in the ultrafiltration backwash pump at preset time intervals t.

[0075] Three sets of data points were recorded for the changes in temperature, liquid level, and pressure over time, including temperature data point (t, T), liquid level data point (t, C1), and pressure data point (t, P), and then three sets of data images were generated, including temperature-time graph, liquid level-time graph, and pressure-time graph.

[0076] Please see Figure 2 As shown, data extraction is performed on the three sets of data images. Preset data fluctuation range limits corresponding to each image are retrieved, including the upper limit of temperature (TMax), the upper limit of liquid level (C1Max), and the upper limit of pressure (PMax). Lower limits of data fluctuation ranges are also retrieved, including the lower limit of temperature (TMin), the lower limit of liquid level (C1Min), and the lower limit of pressure (PMin). The areas exceeding the upper limits of temperature, liquid level, and pressure in each of the three sets of images are obtained and recorded as the cumulative positive deviation. The areas below the lower limits of temperature, liquid level, and pressure in each of the three sets of images are obtained and recorded as the cumulative negative deviation. The difference between the cumulative positive deviation and the cumulative negative deviation is recorded as the cumulative deviation e1.

[0077] Calculate the cumulative deviations e1(T), e1(C1), and e1(P) corresponding to temperature T, liquid level C1, and pressure P, respectively.

[0078] Data extraction is performed on the temperature data points (t, T), liquid level data points (t, C1), and pressure data points (t, P) acquired within the previous preset time interval t, using the formula... Calculate the relative deviations e2(T), e2(C1), and e2(P) corresponding to temperature, liquid level, and pressure using the formula... Calculate the deviation change rates e3(T), e3(C1), and e3(P) corresponding to temperature, liquid level, and pressure. Using the formula... Calculate the control parameters δ1, δ2 and δ3, where λ1, λ2 and λ3 are preset weighting factors.

[0079] Furthermore, the obtained control parameters δ1, δ2, and δ3 are normalized, mapping their specific values ​​to the range of -3 to 3. The mapping function is as follows: , where int is the floor function, for example int(2.6) = 2; where δ1Max, δ2Max, and δ3Max are the upper limits of the fluctuation of control parameters δ1, δ2, and δ3, respectively; where δ1Min, δ2Min, and δ3Min are the lower limits of the fluctuation of control parameters δ1, δ2, and δ3, respectively.

[0080] The ultrafiltration control module performs numerical judgments on the mapped control parameter 1 f(δ1) and control parameter 2 f(δ2) to generate the valve opening command parameter ε1. The specific judgment conditions are shown in Table 1.

[0081] Table 1

[0082] f(δ1)ε1F(δ2) -3 -2 -1 0 1 2 3 -3 0 0 0 1 2 3 4 -2 0 0 1 2 3 4 5 -1 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 9 3 4 5 6 7 8 9 10

[0083] Please see Figure 3 As shown, the temperature control valve is adjusted according to the specific value of the valve opening command parameter ε1, specifically as follows:

[0084] First, the valve opening command parameter is evaluated using a first numerical judgment to determine if the value of ε1 is greater than the preset threshold of 0. If yes, the second numerical judgment is performed; otherwise, the steam valve is closed and the temperature control adjustment ends.

[0085] In the second numerical judgment, it is determined whether the value of ε1 is greater than or equal to the preset threshold of 5. If so, the steam valve is opened and maintained for 10 seconds. Then, the value of ε1 is decremented by one and the system returns to the second numerical judgment to form a loop. The loop ends when the value of ε1 is negative in the second numerical judgment. If negative, the steam valve is opened and maintained for 10 seconds, then the valve is closed and the temperature control ends.

[0086] It should be noted that if the opening and closing time of the steam valve in the plate heat exchanger is set to a fixed value, there will be a lag in the adjustment effect when the water flow changes, affecting the temperature control effect of the plate heat exchanger. This process aims to comprehensively consider flow rate and temperature data, and ensure that the water entering the ultrafiltration equipment has a constant temperature through negative temperature feedback regulation, protecting the pipeline and ultrafiltration system and meeting the operating conditions of the ultrafiltration device.

[0087] The backwash command parameter ε2 is calculated using the formula ε2=K1×f(δ2)+K2×f(δ3), where k1 and k2 are preset influence factors.

[0088] The ultrafiltration backwashing operation is performed according to the specific value of the backwashing command parameter ε2, as follows:

[0089] If the value of the backwash command parameter ε2 is greater than or equal to the preset maximum threshold ε2Max, a first backwash command is sent to the ultrafiltration backwash pump. If the value of the backwash command parameter ε2 is less than the maximum threshold ε2Max but greater than or equal to the minimum threshold ε2Min, a second backwash command is sent to the ultrafiltration backwash pump.

[0090] The first backwash command specifically involves: turning on the ultrafiltration backwash pump and starting the pump start-up timer; pumping the ultrafiltration water output from the ultrafiltration device from the ultrafiltration water tank back into the input end of the ultrafiltration device at a preset first head H1 and a first pump shaft speed n1 for ultrafiltration backwashing. When the pump start-up timer reaches the preset first start-up time T1, the ultrafiltration backwash pump is turned off.

[0091] The second backwash command is as follows: The ultrafiltration backwash pump is turned on and a start-up timer is established. The ultrafiltration water output from the ultrafiltration device is pumped back into the input of the ultrafiltration device from the ultrafiltration water tank at a preset second head H2 and second pump shaft speed n2 for ultrafiltration backwashing. When the start-up timer reaches the preset second start-up time T2, the ultrafiltration backwash pump is turned off.

[0092] In terms of specific values, the first head H1 of the ultrafiltration backwash pump is greater than the second head H2; the first pump shaft speed n1 of the ultrafiltration backwash pump is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

[0093] It should be noted that this process is designed to turn on the ultrafiltration backwash pump when the water pressure drops but the flow rate is high, so as to pump the insufficiently filtered ultrafiltration water back into the ultrafiltration device to ensure that the ultrafiltration water is fully filtered.

[0094] Second embodiment:

[0095] The negative feedback regulation of the reverse osmosis cycle is achieved through PID control of the reverse osmosis subsystem.

[0096] The hardware equipment in the reverse osmosis subsystem includes a precision filter, a reverse osmosis high-pressure flushing pump, a freshwater tank, and a chemical dosing system.

[0097] The reverse osmosis subsystem includes a reverse osmosis sensing module and a reverse osmosis regulation module.

[0098] The reverse osmosis sensing module acquires the influent flow rate Q1 of the precision filter, the liquid level C2 in the freshwater tank, and the conductivity ρ at preset time intervals t.

[0099] Three sets of data points were recorded, showing the changes in influent flow rate Q1, liquid level C2, and conductivity ρ over time. These data points included flow rate data (t, Q1), liquid level data (t, C2), and conductivity data (t, ρ). Three sets of data images were then generated based on these data points: a flow rate-time graph, a liquid level-time graph, and a conductivity-time graph.

[0100] Data extraction is performed on the three sets of data images. Preset data fluctuation range limits corresponding to each image are retrieved, including the upper limit of flow rate Q1Max, the upper limit of liquid level C2Max, and the upper limit of conductivity ρMax. Lower limits of data fluctuation ranges are also retrieved, including the lower limit of flow rate Q1Min, the lower limit of liquid level C2Min, and the lower limit of conductivity ρMin. The areas exceeding the upper limits of flow rate, liquid level, and conductivity in each of the three sets of images are recorded as the cumulative positive deviation. The areas below the lower limits of flow rate, liquid level, and conductivity in each of the three sets of images are recorded as the cumulative negative deviation. The difference between the cumulative positive deviation and the cumulative negative deviation is recorded as the cumulative deviation. The cumulative deviations e1(Q1), e1(C2), and e1(ρ) corresponding to flow rate Q1, liquid level C2, and conductivity ρ are calculated respectively.

[0101] Data extraction is performed on the flow rate data points (t, Q1), liquid level data points (t, C2), and conductivity data points (t, ρ) acquired within the previous preset time interval t, using the formula... Calculate the relative deviations e2(Q1), e2(C2), and e2(ρ) corresponding to flow rate, liquid level, and conductivity, using the formula... Calculate the deviation change rates e3(Q1), e3(C2), and e3(ρ) corresponding to temperature, liquid level, and pressure. Using the formula... Calculate the control parameters δ4, δ5 and δ6, where λ1, λ2 and λ3 are preset weighting factors.

[0102] Furthermore, the obtained control parameters δ4, δ5, and δ6 are normalized, mapping their values ​​to the range of 0 to 100. The mapping function is as follows: , where int is the floor function, for example int(2.6) = 2; where δ4Max, δ5Max, and δ6Max are the upper limits of the fluctuation of control parameters δ4, δ5, and δ6, respectively; where δ4Min, δ5Min, and δ6Min are the lower limits of the fluctuation of control parameters δ4, δ5, and δ6, respectively.

[0103] The reverse osmosis control module calculates the backwash command parameter ε3 using the formula: ε3=K3×f(δ4)+K4×f(δ5), where k3 and k4 are preset weighting factors.

[0104] The reverse osmosis flushing operation is performed according to the specific value of the backwash command parameter ε3, as follows:

[0105] If the value of the backwash command parameter ε3 is greater than or equal to the preset maximum threshold ε3Max, a first backwash command is sent to the reverse osmosis high-pressure flushing pump. If the value of the backwash command parameter ε3 is less than the maximum threshold ε3Max but greater than or equal to the minimum threshold ε3Min, a second backwash command is sent to the reverse osmosis high-pressure flushing pump.

[0106] The first reverse osmosis command specifically involves: turning on the reverse osmosis high-pressure flushing pump and starting the pump start-up timer; pumping freshwater output from the reverse osmosis unit back into the input end of the reverse osmosis unit from the freshwater tank at a preset first head H1 and a first pump shaft speed n1 for reverse osmosis flushing; and turning off the reverse osmosis high-pressure flushing pump when the pump start-up timer reaches the preset first start-up time T1.

[0107] The second reverse osmosis command specifically involves: turning on the reverse osmosis high-pressure flushing pump and starting the pump start-up timer; pumping the freshwater output from the reverse osmosis unit from the freshwater tank back into the input end of the reverse osmosis unit at a preset second head H2 and second pump shaft speed n2 for reverse osmosis flushing. When the pump start-up timer reaches the preset second start-up time T2, the reverse osmosis high-pressure flushing pump is turned off.

[0108] In terms of specific values, the first head H1 is greater than the second head H2; the first pump shaft speed n1 is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

[0109] Furthermore, the dosage of the dosing system is optimized and adjusted based on the control parameter δ6 corresponding to the conductivity, specifically as follows:

[0110] The normalized control parameter f(δ6) is numerically fuzzified using the formula. Calculate the dosing execution parameter ε4, where A is the preset conductivity model constant, B is the preset flux constant, and ε4Max is the preset maximum dosing amount.

[0111] The dosage is adjusted to ε4 at preset time intervals t.

[0112] It should be noted that the dosing system uses ammonia to adjust the pH of the desalinated water. When the pH is adjusted to around 7, the positive or negative charge in the desalinated water will remain within a small range, resulting in low conductivity. Conversely, when the pH is too high or too low, the concentration of charged ions in the desalinated water is high, leading to high conductivity. Therefore, conductivity can indirectly reflect whether the pH of the desalinated water has been adjusted to a suitable range.

[0113] Third embodiment:

[0114] The negative feedback regulation of the mixed bed demineralized water regeneration cycle is achieved through PID control of the mixed bed subsystem.

[0115] The hardware equipment in the mixed bed subsystem includes a mixed ion exchanger, a freshwater pump, and a demineralized water tank.

[0116] The mixed bed subsystem includes a mixed bed sensing module and a mixed bed adjustment module.

[0117] The mixed bed sensing module acquires the conductivity ρ1 of the water entering the mixed ion exchanger at preset time intervals t, and outputs the conductivity ρ2 of the water in the mixed ion exchanger and the flow rate Q2 of the demineralized water flowing into the demineralized water tank.

[0118] Furthermore, the conductivity difference Δρ between the water entering and exiting the mixed ion exchanger is calculated using the formula Δρ=ρ2-ρ1.

[0119] Two sets of data points are recorded, namely the conductivity difference and the demineralized water flow rate, including the conductivity difference data point (t, Δρ) and the demineralized water flow rate data point (t, Q2). Then, two sets of data images are generated based on the two sets of data points, namely the conductivity difference-time graph and the demineralized water flow rate-time graph.

[0120] Data extraction is performed on the two sets of data images. Preset data fluctuation range limits are retrieved for each image, including the upper limit of conductivity difference ΔρMax and the upper limit of flow rate Q2Max; lower limits of data fluctuation range are retrieved, including the lower limit of conductivity difference ΔρMin and the lower limit of flow rate Q2Min. The areas exceeding the upper limits of conductivity difference and flow rate in each of the two sets of images are recorded as the cumulative positive deviation; the areas below the lower limits of conductivity difference and flow rate in each of the two sets of images are recorded as the cumulative negative deviation. The difference between the cumulative positive deviation and the cumulative negative deviation is recorded as the cumulative deviation. The cumulative deviations e1(Δρ) and e1(Q2) corresponding to the conductivity difference Δρ and flow rate Q2 are calculated respectively.

[0121] Data extraction is performed on the conductivity difference data points (t, Δρ) and flow rate data points (t, Q2) obtained within the previous preset time interval t, using the formula... Calculate the relative deviations e2(Δρ) and e2(Q2) corresponding to the conductivity difference and flow rate, using the formula Calculate the rate of change of conductivity difference and flow rate corresponding to the deviation e3(Δρ) and e3(Q2). Using the formula... Calculate the control parameters δ7 and δ8, where λ1, λ2 and λ3 are preset weighting factors.

[0122] Furthermore, the control parameters δ7 and δ8 are numerically normalized, mapping their values ​​to the range of -3 to 3. The mapping function is: , where int is the floor function; where δ7Max and δ8Max are the upper limits of the fluctuation of control parameters δ7 and δ8, respectively; where δ7Min and δ8Min are the lower limits of the fluctuation of control parameters δ7 and δ8, respectively.

[0123] The mixed bed adjustment module performs numerical judgments on the normalized control parameters f(δ7) and f(δ8) to generate the regeneration command parameter ε5. The specific judgment conditions are shown in Table 2.

[0124] Table 2

[0125] f(δ7)ε5F(δ8) -3 -2 -1 0 1 2 3 -3 0 0 0 1 2 3 4 -2 0 0 1 2 3 4 5 -1 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 2 3 4 5 6 7 8 9 3 4 5 6 7 8 9 10

[0126] The freshwater pump is switched on and off according to the specific value of the regeneration command parameter ε5, specifically as follows:

[0127] If the value of the regeneration command parameter ε5 is greater than or equal to the preset maximum threshold ε5Max, a first reverse osmosis command is sent to the freshwater pump. If the value of the regeneration command parameter ε5 is less than the maximum threshold ε5Max but greater than or equal to the minimum threshold ε5Min, a second reverse osmosis command is sent to the freshwater pump.

[0128] The first reverse osmosis command specifically involves: turning on the freshwater pump and starting the pump start-up timer; pumping freshwater output from the reverse osmosis unit from the freshwater tank back into the input end of the reverse osmosis unit at a preset first head H1 and a first pump shaft speed n1 for reverse osmosis flushing; and turning off the freshwater pump when the pump start-up timer reaches the preset first start-up time T1.

[0129] The second reverse osmosis command specifically involves: turning on the freshwater pump and starting the pump start-up timer; pumping the freshwater output from the reverse osmosis unit back into the input end of the reverse osmosis unit from the freshwater tank at a preset second head H2 and second pump shaft speed n2 for reverse osmosis flushing. When the pump start-up timer reaches the preset second start-up time T2, the freshwater pump is turned off.

[0130] In terms of specific values, the first head H1 is greater than the second head H2; the first pump shaft speed n1 is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

[0131] Fourth embodiment:

[0132] Please see Figure 4 As shown, the present invention also provides a scheduling and coordination module, including the PID control function described in the first, second, and third embodiments. The scheduling and coordination module achieves process coordination and error control of the ultrafiltration subsystem, reverse osmosis subsystem, and mixed bed subsystem through pump parameter adjustment. Specifically:

[0133] Control parameter δ2 is obtained from the ultrafiltration subsystem; control parameters δ4 and δ5 are obtained from the reverse osmosis subsystem; and control parameter δ8 is obtained from the mixed bed subsystem.

[0134] Through formula Calculate the overall equilibrium factor S(1,2,3). Where S(1,2) is the equilibrium factor of the ultrafiltration subsystem and the reverse osmosis subsystem; and S(2,3) is the equilibrium factor of the reverse osmosis subsystem and the mixed bed subsystem.

[0135] It should be noted that the overall balance factor quantifies the degree of balance between the influent and effluent velocities of the ultrafiltration subsystem, reverse osmosis subsystem, and mixed bed subsystem.

[0136] When the overall balance factor S(1,2,3) is greater than the preset threshold S(1,2,3)MAX, the balance factors S(1,2) and S(2,3) are numerically evaluated. The specific process is as follows:

[0137] If the value of the balance factor S(1,2) is greater than the preset threshold S(1,2)Max, increase the first head and the first pump shaft speed of the ultrafiltration backwash pump; if the value of the balance factor S(2,3) is greater than the preset threshold S(2,3)Max, increase the first head and the first pump shaft speed of the reverse osmosis high-pressure flushing pump.

[0138] It should be understood that the terms “comprising” and “including” used in this disclosure and claims indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0139] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. As used in this disclosure and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this disclosure and claims means any combination and all possible combinations of one or more of the associated listed items, and includes such combinations;

[0140] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to any specific implementation. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A demineralized water treatment system based on pressure feedback regulation, comprising an ultrafiltration sensing module, a reverse osmosis sensing module, a mixed bed sensing module, and a scheduling and coordination module, characterized in that: The ultrafiltration sensing module, reverse osmosis sensing module, and mixed bed sensing module collect various data during the operation of the demineralized water treatment system at preset time intervals. Based on the collected data, eight sets of two-dimensional data images related to time are generated, including temperature-time graph, liquid level C1-time graph, pressure-time graph, flow rate-time graph, liquid level C2-time graph, conductivity-time graph, conductivity difference-time graph, and demineralized water flow rate-time graph. Through data extraction, data fusion, and normalization processing in the images, the mapped control parameters f1 (δ1), f2 (δ2), f3 (δ3), f4 (δ4), f5 (δ5), f6 (δ6), f7 (δ7), and f8 (δ8) are obtained. The scheduling and coordination module achieves coordinated process control of the ultrafiltration subsystem, reverse osmosis subsystem, and mixed bed subsystem through data analysis and water pump regulation. The hardware equipment in the ultrafiltration subsystem includes a plate heat exchanger, an ultrafiltration unit, an ultrafiltration water tank, and an ultrafiltration backwash pump. The hardware equipment in the reverse osmosis subsystem includes a precision filter, a reverse osmosis high-pressure flushing pump, a freshwater tank, and a dosing system. The hardware equipment in the mixed bed subsystem includes a mixed ion exchanger, a freshwater pump, and a demineralized water tank. The data collected during the operation of the demineralized water treatment system include: The following parameters are considered: plate heat exchanger temperature T, ultrafiltration water tank level C1, ultrafiltration backwash pump pressure P, precision filter inlet flow rate Q1, freshwater tank liquid level C2, conductivity ρ, water conductivity ρ1 entering the mixed ion exchanger, water conductivity ρ2 exiting the mixed ion exchanger, demineralized water flow rate Q2 flowing into the demineralized water tank, and conductivity difference Δρ. The conductivity difference Δρ is calculated using the formula Δρ = ρ2 - ρ1, where ρ1 is the conductivity of the water entering the mixed ion exchanger, and ρ2 is the conductivity of the water exiting the mixed ion exchanger. The data extraction and processing process is as follows: Retrieve the preset data fluctuation range limits corresponding to each group of images, including the upper limit XMax and the lower limit XMin; obtain the area of ​​the part above the upper limit of data fluctuation in the eight groups of images respectively, and record it as the cumulative deviation positive value; obtain the area of ​​the part below the lower limit of data fluctuation in the eight groups of images respectively, and record it as the cumulative deviation negative value; record the difference between the cumulative deviation positive value and the cumulative deviation negative value as the cumulative deviation value e1(X). For the temperature data point (t, X) acquired within the previous preset time interval t, the formula is used to... Calculate the relative deviation e2(X) for each image; using the formula Calculate the deviation change rate e3(X) for each image, where X = T, C1, P, Q1, C2, ρ, Q2 and Δρ; The cumulative deviation, relative deviation, and rate of change of deviation for each group of data are fused and normalized. The specific process is as follows: Through formula Calculate the control parameters δ1, δ2, and δ3; Through formula Calculate the control parameters δ4, δ5, and δ6; Through formula Calculate control parameters δ7 and δ8, where λ1, λ2 and λ3 are preset weighting factors; The specific process by which the scheduling and coordination module achieves coordinated control of the ultrafiltration subsystem, reverse osmosis subsystem, and mixed bed subsystem through data analysis and water pump regulation is as follows: Control parameters δ2 are obtained from the ultrafiltration subsystem; control parameters δ4 and δ5 are obtained from the reverse osmosis subsystem; control parameter δ8 is obtained from the mixed bed subsystem. Through formula Calculate the overall equilibrium factor S(1,2,3); where S(1,2) is the equilibrium factor of the ultrafiltration subsystem and the reverse osmosis subsystem; and where S(2,3) is the equilibrium factor of the reverse osmosis subsystem and the mixed bed subsystem. When the overall balance factor S(1,2,3) is greater than the preset threshold S(1,2,3)MAX, the balance factors S(1,2) and S(2,3) are numerically judged. If the value of the balance factor S(1,2) is greater than the preset threshold S(1,2)Max, the first head and the first pump shaft speed of the ultrafiltration backwash pump are increased. If the value of the balance factor S(2,3) is greater than the preset threshold S(2,3)Max, the first head and the first pump shaft speed of the reverse osmosis high-pressure flushing pump are increased.

2. The demineralized water treatment system based on pressure feedback regulation according to claim 1, characterized in that, It also includes an ultrafiltration conditioning module, a reverse osmosis conditioning module, and a mixed bed conditioning module; The ultrafiltration regulation module, reverse osmosis regulation module, and mixed bed regulation module perform numerical judgment, data fusion, and targeted data execution based on the mapped control parameters.

3. The demineralized water treatment system based on pressure feedback regulation according to claim 1, characterized in that, For the obtained control parameters δ1, δ2, and δ3, their specific values ​​are mapped to the range of -3 to 3. The mapping function is as follows: , where int is the floor function; where δ1Max, δ2Max, and δ3Max are the upper limits of fluctuation for control parameters δ1, δ2, and δ3, respectively; and where δ1Min, δ2Min, and δ3Min are the lower limits of fluctuation for control parameters δ1, δ2, and δ3, respectively. For the obtained control parameters δ4, δ5, and δ6, their specific values ​​are mapped to the range of 0 to 100. The mapping function is as follows: δ4Max, δ5Max, and δ6Max are the upper limits of the fluctuation of control parameters δ4, δ5, and δ6, respectively; δ4Min, δ5Min, and δ6Min are the lower limits of the fluctuation of control parameters δ4, δ5, and δ6, respectively. For control parameters δ7 and δ8, their specific values ​​are mapped to the range of -3 to 3; the mapping function is: δ7Max and δ8Max are the upper limits of the fluctuation of control parameters δ7 and δ8, respectively; δ7Min and δ8Min are the lower limits of the fluctuation of control parameters δ7 and δ8, respectively.

4. The demineralized water treatment system based on pressure feedback regulation according to claim 2, characterized in that, The specific process by which the ultrafiltration adjustment module performs numerical judgment, data fusion, and targeted data execution is as follows: Numerical judgment is performed on the mapped control parameter 1 f(δ1) and control parameter 2 f(δ2) to generate valve opening command parameter ε1; data fusion is performed on the mapped control parameter 2 f(δ2) and mapped control parameter 3 f(δ3) to generate backwash command parameter ε2. The temperature control operation is performed according to the generated valve opening command parameter ε1. First, the valve opening command parameter is evaluated for the first time to determine whether the value of ε1 is greater than the preset threshold 0. If it is, the second evaluation is performed. If not, the steam valve is closed and the temperature control operation ends. In the second numerical judgment, it is determined whether the value of ε1 is greater than or equal to the preset threshold 5; if so, the steam valve is opened and maintained for 10 seconds; then the value of ε1 is decremented by one and the second numerical judgment is returned to form a loop until the value of ε1 is negative in the second numerical judgment, at which point the loop is exited; if not, the steam valve is opened and maintained for 10 seconds, then the valve is closed and the temperature control is ended. The ultrafiltration backwashing operation is performed according to the specific value of the backwashing command parameter ε2. If the value of the backwashing command parameter ε2 is greater than or equal to the preset maximum threshold ε2Max, a first backwashing command is sent to the ultrafiltration backwashing pump. When the value of the backwashing command parameter ε2 is less than the maximum threshold ε2Max and greater than or equal to the minimum threshold ε2Min, a second backwashing command is sent to the ultrafiltration backwashing pump. The first backwash command is as follows: turn on the ultrafiltration backwash pump and start the pump start timer, and pump the ultrafiltration water output from the ultrafiltration device from the ultrafiltration water tank back into the input end of the ultrafiltration device with the preset first head H1 and the first pump shaft speed n1 to perform ultrafiltration backwash; when the pump start timer reaches the preset first pump start time T1, turn off the ultrafiltration backwash pump. The second backwash command is as follows: turn on the ultrafiltration backwash pump and start the pump start timer. Pump the ultrafiltration water output from the ultrafiltration device from the ultrafiltration water tank back into the input end of the ultrafiltration device with the preset second head H2 and the second pump shaft speed n2 to perform ultrafiltration backwashing. When the pump start timer reaches the preset second pump start time T2, turn off the ultrafiltration backwash pump. In terms of specific values, the first head H1 of the ultrafiltration backwash pump is greater than the second head H2; the first pump shaft speed n1 of the ultrafiltration backwash pump is greater than the second pump shaft speed n2; and the first pump start-up time T1 is greater than the second pump start-up time T2.

5. The demineralized water treatment system based on pressure feedback regulation according to claim 2, characterized in that, The specific process by which the reverse osmosis control module performs numerical judgment, data fusion, and targeted data execution is as follows: The backwash command parameter ε3 is obtained through data fusion. The reverse osmosis flushing operation is performed according to the specific value of the backwash command parameter ε3. If the value of the backwash command parameter ε3 is greater than or equal to the preset maximum threshold ε3Max, the first reverse osmosis command is sent to the reverse osmosis high-pressure flushing pump. When the value of the backwash command parameter ε3 is less than the maximum threshold ε3Max and greater than or equal to the minimum threshold ε3Min, the second reverse osmosis command is sent to the reverse osmosis high-pressure flushing pump. The first reverse osmosis command is specifically as follows: turn on the reverse osmosis high-pressure flushing pump and start the pump start timer, and pump the fresh water output from the reverse osmosis unit from the fresh water tank back into the input end of the reverse osmosis unit with the preset first head H1 and the first pump shaft speed n1 to perform reverse osmosis flushing; when the pump start timer reaches the preset first pump start time T1, turn off the reverse osmosis high-pressure flushing pump. The second reverse osmosis command is as follows: turn on the reverse osmosis high-pressure flushing pump and start the pump start timer. Pump the fresh water output from the reverse osmosis device from the fresh water tank back into the input end of the reverse osmosis device at the preset second head H2 and second pump shaft speed n2 for reverse osmosis flushing. When the pump start timer reaches the preset second start time T2, turn off the reverse osmosis high-pressure flushing pump. In terms of specific values, the first head H1 is greater than the second head H2; the first pump shaft speed n1 is greater than the second pump shaft speed n2; and the first pump start time T1 is greater than the second pump start time T2. The dosage of the dosing system is optimized and adjusted based on the control parameter δ6 corresponding to the conductivity. The normalized control parameter δ6 is then subjected to numerical fuzzification processing, and the result is obtained using the formula... Calculate the dosing execution parameter ε4, where B is the preset flux constant and ε4Max is the preset maximum dosage; adjust the dosage to ε4 every preset time interval t.

6. The demineralized water treatment system based on pressure feedback regulation according to claim 2, characterized in that, The specific process by which the mixed bed adjustment module performs numerical judgment, data fusion, and targeted data execution is as follows: Numerical judgments are performed on the normalized control parameters f(δ7) and f(δ8) to generate the regeneration command parameter ε5; The freshwater pump is switched on and off according to the specific value of the regeneration command parameter ε5.

Images