Reverse osmosis pure water production method and equipment based on two-stage membrane module collaborative purification

Abstract

The invention discloses a reverse osmosis pure water production method and equipment based on two-stage membrane module collaborative purification, and relates to the technical field of sewage treatment. In the water quality monitoring stage after pretreatment, preliminary water inlet optimization is performed on the desalination process of the reverse osmosis assembly based on the obtained ion migration state data so as to reduce the surface scaling rate of the reverse osmosis membrane, and then the surface scaling rate of the reverse osmosis membrane is reduced based on the water inlet salt content of the water inlet corresponding to the first-stage reverse osmosis membrane after preliminary water inlet optimization. Performing pressure-flow rate cooperative control on the pressure fine desalination process of the primary reverse osmosis membrane, performing circulation flow rate adjustment at the same time, and finally adjusting water inlet parameters of a reverse osmosis assembly based on the conductivity of a corresponding specified position in a water inlet buffer tank of the primary reverse osmosis membrane and in combination with a water quality feedback state of water produced by the secondary reverse osmosis membrane. Refined and self-adaptive cooperative control of the reverse osmosis assembly is realized, and the problem of desalination efficiency fluctuation caused by differential pressure change of a two-stage membrane in application in the prior art is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewage treatment technical field, especially to the reverse osmosis pure water production method and equipment based on two-stage membrane module cooperative purification. BACKGROUND

[0002] In the pure water production process, the core of the pure water production equipment is composed of a filter, an ion exchange membrane, a precision filter, a reverse osmosis membrane (RO), and a dilute acid and dilute alkali collection and delivery structure. After the equipment receives raw water, it first enters the filter and water storage tank for pretreatment steps. Hydrolysis generates hydrogen ions and hydroxyl ions, which can adjust the pH value of the raw water to stabilize it in the best range for subsequent filtration processing links. At the same time, the substances in the raw water that can cause membrane module fouling are directed to migrate to a specific area, where they are converted into a form that is easy to handle and then trapped, thereby completing the pretreatment of the raw water. The pretreated water is then sent to the RO membrane water inlet buffer tank through the pipeline and delivered to the reverse osmosis membrane for desalination. The water flow is driven to pass through the reverse osmosis membrane by applying pressure. In this process, the remaining impurities in the water are trapped by the reverse osmosis membrane, and only water molecules can pass through smoothly, achieving deep desalination and finally generating high-purity pure water. Part of the water after the RO membrane is returned to the water inlet end using a valve to reduce the salt content. In addition, dilute acid and dilute alkali are also produced during operation, and Joule heat is also generated during the ion migration process driven by the electric field. These substances are introduced into a special membrane cleaning circulation process, and the heat is collected using a heat-conducting medium to complete the collection of the electric field waste heat for subsequent temperature deviation compensation. The equipment purifies the water through the process of raw water→raw water tank→raw water pump→multi-media filter→activated carbon filter→softener→first-stage precision filter→second-stage precision filter→fresh water chamber→water inlet buffer tank→first-stage reverse osmosis→second-stage reverse osmosis→purified water tank→pure water pump→water use point.

[0003] For example, the Chinese invention patent with publication number CN104230076B discloses a treatment method for reverse osmosis concentrated water in the process of urban sewage reuse, which includes: adjusting the pH value of the reverse osmosis concentrated water and heating it to a certain temperature, then delivering it to a hydrophobic membrane module for concentration treatment, using vacuum pumping to condense the permeated steam into water, which is used for direct reuse or mixed with reverse osmosis water for reuse, using a partial concentrated water circulation method to concentrate the generated concentrated water and enter a gravity sedimentation separator for classification, the upper clear liquid after separation enters a microfiltration membrane unit to remove suspended solids, and the wastewater containing a large amount of suspended solids is subjected to solid-liquid separation and the separated mother liquor is sent to a spray drying unit for drying treatment.

[0004] For example, the Chinese invention patent with publication number CN105417898B discloses a method for treating reverse osmosis concentrated water and ultrafiltration backwash water in a double membrane system, which comprises: using a pre-coated membrane to resist ultrafiltration membrane pollution, an aerobic tank to treat zeolite powder, and ozone to treat reverse osmosis concentrated water, to comprehensively treat the ultrafiltration membrane and reverse osmosis process; wherein, during the ozone treatment process, the hydrogen peroxide and ozone are optimized and controlled, the treated wastewater is subjected to biochemical circulation treatment before entering the front end of the sewage plant, the pollutants such as COD and ammonia nitrogen in the wastewater are removed, and the adsorption material of the ultrafiltration membrane system is pre-coated zeolite powder.

[0005] The above-mentioned technology at least has the following technical problems: In the prior art, during the purification of raw water, the stable operation of the reverse osmosis membrane needs to be adapted to the salt content of the inlet water, and the operation parameters need to be dynamically adjusted according to the real-time changes of the total dissolved solids and the salt content of the current water body. When the raw water is mixed with more high-salt water sources due to the composition of the water source or the front filter fails (such as resin softening failure), resulting in an increase in the salt content, the front component (such as the precision filter) cannot completely suppress the increase in the salt content, and in the case of short-term sudden fluctuations such as heavy rain causing the total dissolved solids of the raw water to increase, the pretreatment step cannot timely process a large volume of high-salt water, at this time, the impurities on the membrane surface are overloaded, causing the pressure difference between the inlet and outlet of the reverse osmosis membrane to increase rapidly, and there is a problem of high change rate of the internal and external pressure difference of the corresponding double-stage reverse osmosis membrane during the reverse osmosis process. SUMMARY

[0006] In order to solve the technical problem of high change rate of the internal and external pressure difference of the corresponding double-stage reverse osmosis membrane during the reverse osmosis process in the prior art, the embodiments of the present application provide a reverse osmosis pure water production method and equipment based on double-stage membrane component cooperative purification. The technical solution is as follows: On the one hand, a reverse osmosis pure water production method based on double-stage membrane component cooperative purification is provided, which is realized based on a reverse osmosis pure water production equipment based on double-stage membrane component cooperative purification, and the method comprises: Step one, in the pretreated water quality monitoring stage, based on the obtained ion migration state data, the desalination process of the reverse osmosis assembly is optimized for preliminary water intake to reduce the scaling rate on the surface of the reverse osmosis membrane, the preliminary water intake optimization includes ion membrane switching and cleaning state control, the reverse osmosis assembly includes a fresh water chamber containing an ion exchange membrane, a primary reverse osmosis membrane and a secondary reverse osmosis membrane; step two, based on the salt content of the water at the corresponding water inlet of the primary reverse osmosis membrane after the preliminary water intake optimization, the pressure- flow rate coordinated control of the pressure desalination process of the primary reverse osmosis membrane is carried out, and the circulating flow rate is adjusted at the same time to reduce the deposition of residual pollutants on the membrane surface; step three, based on the conductivity of the corresponding specified position in the primary reverse osmosis membrane water buffer tank, and combined with the water quality feedback state of the secondary reverse osmosis membrane, the water intake parameters of the reverse osmosis assembly are adjusted to reduce the concentration polarization and membrane pollution caused by the water flow at the water inlet of the primary reverse osmosis membrane, the water intake parameters include electric field intensity and water salt content.

[0007] In another aspect, a reverse osmosis pure water production equipment based on a two-stage membrane assembly cooperative purification is provided, which is applied to a reverse osmosis pure water production method based on a two-stage membrane assembly cooperative purification, and the equipment comprises: a preliminary filter device, a precision filter device, a fresh water adjusting device and a two-stage reverse osmosis device. The preliminary filter device comprises a preliminary filter for preliminary filtering of raw water, and a flow meter for detecting flow and flow rate; the precision filter device comprises a precision filter for close filtering of the water after preliminary filtering, a flow sensor for detecting flow and flow rate, and a turbidity sensor for detecting solid particle content of the water; the fresh water adjusting device comprises a flow sensor for detecting flow at the inlet and outlet of the fresh water chamber, a voltage sensor for detecting voltage value of electrolytic adjustment in the fresh water chamber, a pH sensor for detecting pH value before and after fresh water adjustment, and a conductivity sensor for detecting salt content of the water in the buffer tank; the two-stage reverse osmosis device comprises a flow sensor for detecting flow and flow rate of the primary reverse osmosis membrane and the secondary reverse osmosis membrane, a pressure sensor for detecting pressure deviation of the two-stage reverse osmosis membrane and membrane flux pressure, and a conductivity sensor for detecting conductivity of water inlet and water outlet of the two-stage reverse osmosis membrane.

[0008] The technical scheme provided by the embodiment of the application has at least the following beneficial effects: 1. Based on the preliminary feed water optimization of ion migration status and the synergistic design of the ion exchange membrane desalination chamber and the two-stage reverse osmosis membrane, the feed water is classified into three categories according to the initial pH value in the desalination chamber. When the pH value is higher than the preset range, the focus is on monitoring the migration status of anions to enhance the migration efficiency of cations and reduce the feed water pH. When the pH value is lower than the preset range, the focus shifts to monitoring the migration status of cations to enhance the migration of anions and raise the feed water pH. When the pH is within the acceptable range, the operating conditions are maintained to ensure stability. This approach matches classification judgment with migration status monitoring, ion type adaptation with dynamic adjustment of electric field strength, so that the ion exchange membrane desalination chamber guides scale-prone ions away from the mainstream feed water through directional ion migration, reducing their probability of entering the subsequent RO components. By using ion migration status data to guide the preliminary feed water optimization of the RO components, the water entering the first-stage RO not only has a stable pH but also reduces the content of scale-prone ions, thus reducing the probability of scaling on the RO membrane surface from the source.

[0009] 2. Pressure-flow rate coordinated control based on feed water salinity: Taking the salinity in the primary RO feed water buffer tank as the core basis, flow rate control is synchronously linked during the pressure-based desalination process. When the feed water salinity exceeds the upper limit, the membrane shear force is increased to prevent salt accumulation on the membrane surface. When the feed water salinity is below the lower limit, the pressure reduction step is calculated to reduce energy consumption, while maintaining or fine-tuning the flow rate to ensure water production efficiency. When the feed water salinity is stable, the current pressure is maintained, and the osmotic pressure difference between the inlet and outlet is monitored in real time. Through dynamic adaptation of pressure and flow rate, the desalination rate can be guaranteed by increasing pressure when the salinity is higher than the preset value, and concentration polarization can be avoided by optimizing the flow rate. When the salinity is lower than the preset value, energy consumption is saved by reducing pressure, while water production is guaranteed by stabilizing the flow rate. When the pipeline is blocked, the flow rate is not forcibly maintained by high pressure, but the blockage problem is solved by adjusting the flow rate to avoid membrane damage.

[0010] 3. By implementing cross-membrane linkage control of the cleaning status, the cleaning of ion exchange membranes and RO membranes are deeply integrated. Simultaneously, the reuse logic of the cleaning solution is optimized, achieving a dual improvement in cleaning efficiency and resource utilization of the two-stage membrane modules. The ion exchange membrane cleaning status control is based on the pH value of the freshwater outlet. When the pH deviates, the subsequent scaling efficiency is reduced by shortening the circulation time, providing a basis for adjusting the RO membrane circulation flow rate. Flow rate optimization reduces the probability of scaling on the RO membrane surface. Simultaneously, it determines whether the cleaning solution concentration meets the standard: if it does, a reflux command is sent to reuse the cleaning solution; if not, a waste command is sent to discharge it into wastewater treatment. The cleaning effect of the ion exchange membrane directly guides the flow rate adjustment of the RO membrane, avoiding the risk of RO scaling due to incomplete ion exchange membrane cleaning.

[0011] 4. By optimizing the feed water parameters driven by the synergistic desalination index, a quantitative evaluation system for the synergistic efficiency of the two-stage RO system was constructed. Based on this index, the electric field strength and feed water salinity were dynamically adjusted to achieve precise control of deep desalination and energy consumption balance. The overall desalination synergistic efficiency of the two-stage RO system was quantified by combining the first and third conductivity values. If the synergistic desalination index exceeds the upper limit, desalination is enhanced by improving ion migration efficiency. If the index is below the lower limit, the electric field strength of the membrane stack is reduced to lower energy consumption, and the feed water buffer tank flow rate is adjusted simultaneously. The synergistic desalination index allows for a direct assessment of the overall synergistic effect of the two-stage RO system, avoiding overall efficiency imbalances caused by single-stage parameter optimization. The linkage adjustment of electric field strength and feed water salinity not only addresses desalination failure issues but also reduces energy consumption while ensuring effective desalination. The combination of waste heat compensation and reflux regulation further ensures the stability of feed water temperature and salinity.

[0012] 5. Through voltage-flow matching control of the freshwater chamber, based on the preset voltage-flow matching curve, the electrolysis voltage and the influent flow rate are dynamically and synchronously adjusted to optimize ion migration efficiency and ensure the stability of RO influent. When the electrolysis voltage increases relative to the set value, the decrease in the speed of the influent variable frequency pump is calculated through the voltage-flow matching curve, and the influent flow rate is reduced to extend the hydraulic residence time of ions in the freshwater chamber. When the flow rate decreases, the speed increases. Through the synchronous adjustment of voltage and flow rate, incomplete desalination caused by insufficient residence time of ions under high voltage is avoided, and efficiency waste caused by excessive residence time under low voltage is also prevented. Attached Figure Description

[0013] 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.

[0014] Figure 1 A schematic diagram of the reverse osmosis pure water production method based on synergistic purification of a two-stage membrane module provided in an embodiment of the present invention; Figure 2 The flowchart for optimizing the initial feed water for reverse osmosis provided in this embodiment of the invention; Figure 3 The flowcharts for pressure-flow rate coordinated circulation adjustment and reverse osmosis feed water parameter adjustment provided in the embodiments of the present invention are shown. Detailed Implementation

[0015] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0016] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0017] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0018] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0019] This invention provides a reverse osmosis pure water production method based on synergistic purification using a two-stage membrane module. This method can be implemented using a reverse osmosis pure water production device based on synergistic purification using a two-stage membrane module. Figure 1 The flowchart shown illustrates a reverse osmosis pure water production method based on synergistic purification using a two-stage membrane module. The process can include the following steps: Step 1: In the water quality monitoring stage after pretreatment, preliminary feed water optimization is performed on the desalination process of the reverse osmosis module based on the acquired ion migration state data to reduce the scaling rate on the reverse osmosis membrane surface. Preliminary feed water optimization includes ion membrane switching and cleaning status control. The reverse osmosis module includes a freshwater chamber containing an ion exchange membrane, a primary reverse osmosis membrane, and a secondary reverse osmosis membrane; Step 2: Based on the preliminary feed water optimization, at the inlet of the primary reverse osmosis membrane... The feed water salinity is used to control the pressure-flow rate of the first-stage reverse osmosis membrane during pressure fine desalination, while adjusting the circulation flow rate to reduce the deposition of residual pollutants on the membrane surface. Step 3: Based on the conductivity at a designated location in the feed water buffer tank of the first-stage reverse osmosis membrane, and combined with the feedback status of the permeate water quality of the second-stage reverse osmosis membrane, the feed water parameters of the reverse osmosis module are adjusted to reduce concentration polarization and membrane fouling caused by the feed water flow rate at the inlet of the first-stage reverse osmosis membrane, thereby stabilizing the permeate water quality and improving the pure water recovery rate. The feed water parameters include electric field strength and feed water salinity.

[0020] In a specific embodiment, for example, in the process of purifying pure water for food and pastry, the pretreatment stage can only remove basic impurities and does not dynamically adjust the treatment strategy in conjunction with the ion migration state. The parameters such as pressure and flow rate of the reverse osmosis system cannot be coordinated with the salinity of the feed water and the quality of the product water in real time. Occasionally, the quality of the product water fluctuates, which may affect the stability of the dough during the pastry making process.

[0021] When the raw water enters the pure water production, the pretreatment stage will carry out preliminary water optimization according to the ion migration state data, through the ion membrane switching and cleaning state control, guide the easy scaling ions to separate from the main water inlet channel, reduce the probability of these ions entering the subsequent reverse osmosis component, so as to help reduce the scaling situation on the surface of the reverse osmosis membrane.

[0022] After entering the first reverse osmosis link, based on the salt content of the preliminary optimized water, the system will carry out pressure-flow rate coordinated control on the pressure desalination process, and adjust the circulation flow rate at the same time, effectively reducing the deposition of residual pollutants on the surface of the first reverse osmosis membrane. Subsequently, the conductivity in the water inlet buffer tank of the first reverse osmosis membrane and the water quality feedback of the second reverse osmosis membrane will be combined to adjust the electric field strength and the salt content of the reverse osmosis component, further reduce the concentration polarization and membrane pollution caused by the water flow problem of the first reverse osmosis membrane, and finally keep the water quality of the whole system stable, while helping to improve the pure water recovery rate and ensure the continuous and stable operation of the system.

[0023] As shown in Figure 2 The process diagram corresponding to the reverse osmosis preliminary water optimization provided by the embodiment of the application is shown, first, the water classification is carried out, and after the classification is completed, the pH value of the water outlet is monitored, according to the initial pH value of the water, it is judged what interval range it is in, in order to adjust the electric field strength, adjust the voltage and maintain the current unchanged, the pH value of the water outlet is monitored, and the interval is judged based on the obtained pH value, in order to adjust the electrolysis voltage and match the water flow, after the water flow matching is completed, the cleaning state control is carried out, the cleaning state control includes ion exchange membrane cleaning state control and reverse osmosis membrane cleaning state control.

[0024] Further, the desalination process of the reverse osmosis assembly is preliminarily optimized, and the specific process is as follows: according to the initial pH value in the fresh water chamber, the initial water is classified, specifically: the first type, if the initial pH value in the fresh water chamber is greater than the maximum value of the preset water interval, the anion migration state in the fresh water chamber is monitored, and the positive membrane switching instruction is sent to prompt the preset personnel to check the current ion exchange membrane, and the pH value of the water inlet of the fresh water chamber is reduced; if the current fresh water chamber is in the cation migration state, the electric field intensity increase value is obtained based on the current cation migration rate to enhance the migration efficiency of the cation; the second type, if the initial pH value in the fresh water chamber is within the preset water interval, it indicates that the working state of the first reverse osmosis membrane is qualified, and the current pH value is maintained; the third type, if the initial pH value in the fresh water chamber is less than the minimum value of the preset water interval, the cation migration state in the fresh water chamber is monitored, and the negative membrane switching instruction is sent to prompt the preset personnel to check the current ion exchange membrane, and the pH value of the water inlet of the fresh water chamber is improved; if the current fresh water chamber is in the anion migration state, the voltage increase value on both sides of the ion exchange membrane is obtained through the ion-electric field mapping relationship based on the current anion migration rate to enhance the driving force of the electric field on the ion; after monitoring the ion migration state in the fresh water chamber, the pH value of the fresh water chamber outlet is monitored.

[0025] Wherein, the pH value of the fresh water chamber outlet is monitored, specifically: if the pH value at the outlet of the fresh water chamber is greater than the maximum value of the preset water interval, the outlet pH value is input into the RO optimal-electrolysis voltage mapping relationship based on the outlet pH value, to obtain the electrolysis voltage increase value in the fresh water chamber, to increase the migration rate of anions to the acid chamber, and the outlet pH value deviation represents the difference between the obtained pH value at the outlet of the fresh water chamber and the maximum value of the preset water interval; if the pH value at the outlet of the fresh water chamber is less than the minimum value of the preset water interval, the outlet pH value is input into the RO optimal-electrolysis voltage mapping relationship based on the outlet pH value, to obtain the electrolysis voltage decrease value in the fresh water chamber, to reduce the migration rate of cations to the alkali chamber, and the outlet pH value deviation represents the difference between the obtained pH value at the outlet of the fresh water chamber and the minimum value of the preset water interval; if the pH value at the outlet of the fresh water chamber is within the preset water interval, the current electrolysis voltage is maintained, and the fresh water chamber inlet flow rate is matched with the electrolysis voltage, specifically: if the current electrolysis voltage is increased relative to the set electrolysis voltage, the inlet variable frequency pump operating speed reduction value is obtained according to the preset voltage-flow rate matching curve, and the flow rate is reduced to prolong the hydraulic residence time of the ion; if the current electrolysis voltage is reduced relative to the set electrolysis voltage, the inlet variable frequency pump operating speed increase value is obtained according to the preset voltage-flow rate matching curve, and the flow rate is increased to reduce the hydraulic residence time; the voltage-flow rate matching curve is used to visualize the mapping relationship between the corresponding electrolysis voltage and the inlet flow rate in the electrolytic water treatment process, and when the electrolysis voltage is adjusted, the adjustment value of the inlet flow rate is obtained through the curve.

[0026] Specifically, the cleaning state control includes ion exchange membrane cleaning state control for improving electrolysis efficiency and reverse osmosis membrane cleaning state control for improving reverse osmosis efficiency. The ion exchange membrane cleaning state control includes the following steps: real-time monitoring of the pH value of the fresh water outlet corresponding to the ion exchange membrane in the cleaning tank; if the pH value of the fresh water outlet is not in the preset outlet interval, the pH value deviation of the outlet is input into the ion outlet-circulation time mapping relationship to obtain a cycle time reduction value of the desalination flow rate cycle, so as to reduce the subsequent corresponding fouling efficiency; the reverse osmosis membrane cleaning state control includes the following steps: based on the cleaning solution concentration deviation after the ion exchange membrane cleaning state control, obtaining the cycle flow rate adjustment value of the double-stage reverse osmosis membrane to reduce the fouling probability on the surface of the double-stage reverse osmosis membrane; the double-stage reverse osmosis membrane includes a primary reverse osmosis membrane and a secondary reverse osmosis membrane; the cleaning solution concentration deviation is used to reflect the cleaning degree corresponding to the double-stage reverse osmosis membrane; if the cleaning solution concentration after the reverse osmosis membrane cleaning state control is greater than the preset cleaning solution concentration, a backflow instruction is sent to reuse the cleaning solution, otherwise a cleaning solution waste instruction is sent to discharge the cleaning solution to the wastewater treatment; the cleaning solution concentration includes cleaning acid solution and cleaning alkali solution.

[0027] In the present embodiment, the increase in electric field intensity and the increase in voltage are obtained according to the ion migration rate, which is based on the ion-electric field mapping relationship obtained by the support vector regression algorithm, taking the ion migration rate in the historical data as the input and the historical electric field intensity and voltage as the output for training, and embedding the trained model to receive the ion migration rate data in real time and output the increase in electric field intensity or the increase in voltage; the preset water inlet interval is the working interval of the pH value of the first RO membrane in the reverse osmosis assembly according to the used reverse osmosis membrane, the RO optimal-electrolysis voltage mapping relationship is to input the obtained outlet pH value deviation to the electrolysis voltage controller in the fresh water adjusting device, and the controller adjusts the electrolysis voltage in real time through the pre-constructed RO optimal-electrolysis voltage corresponding relationship to adapt to the water inlet pH requirement of the reverse osmosis assembly, and the construction process of the RO optimal-electrolysis voltage corresponding relationship is as follows: based on the historical operation data, the water inlet pH, RO parameters (such as water production rate, desalination rate) and electrolysis voltage of the reverse osmosis assembly under different working conditions are extracted; the parameter combination of RO performance under each working condition is selected, and the corresponding electrolysis voltage is associated; then through data fitting and error correction, the corresponding relationship library can be called, and the construction process of the following mapping relationship is similar to the RO optimal-electrolysis voltage mapping relationship, the voltage-flow matching curve is obtained by training the historical data of electrolysis voltage as input and flow as output based on the AdaBoost regression algorithm, the preset outlet interval is obtained by the stable operation interval of the reverse osmosis assembly in the historical ion exchange membrane cleaning state control process, the ion outlet-circulation time mapping relationship is to input the obtained outlet pH value deviation to the circulation pump controller of the fresh water adjusting device, and the controller adjusts the circulation time in real time through the pre-set ion outlet-circulation time corresponding relationship, and the pre-set ion outlet-circulation time corresponding relationship is obtained by extracting parameters based on historical operation data, the circulation flow rate adjustment value of the double-stage reverse osmosis membrane obtained from the cleaning solution concentration deviation is obtained by training the historical data of cleaning solution concentration deviation as input and circulation flow rate as output based on the LightGBM algorithm, the outlet pH value deviation represents the difference between the obtained outlet pH value and the maximum / minimum value of the preset outlet interval, the cleaning solution concentration deviation represents the difference between the cleaning solution concentration before the ion exchange membrane cleaning state control and the cleaning solution concentration after the ion exchange membrane cleaning state control, and the preset cleaning solution concentration is the result of summing and averaging the historical cleaning solution concentration in the historical reverse osmosis membrane cleaning state control.

[0028] By regulating according to the initial pH value of the fresh water chamber, combining with dynamic adjustment of the electric field intensity or the voltage on both sides of the ion exchange membrane, and cooperating with secondary monitoring of the outlet pH value and optimization of the electrolysis voltage, the outlet pH value of the fresh water chamber can be stabilized in the interval suitable for the subsequent reverse osmosis component, reducing the retention of ions prone to scaling and reducing the risk of reverse osmosis membrane scaling from the source. At the same time, the matching adjustment of the electrolysis voltage and the fresh water chamber inlet flow rate can make the ion hydraulic retention time and the electrolysis driving force suitable, improve the ion migration efficiency, and ensure the desalination effect.

[0029] In the cleaning state control, the ion exchange membrane optimizes the desalination flow rate cycle length according to the pH deviation, and the reverse osmosis membrane adjusts the circulation flow rate according to the concentration deviation of the cleaning solution, which can reduce the pollution and scaling of the two types of membranes, prolong the stable operation period of the membranes, and also reduce the waste of chemicals and wastewater discharge through the reuse of the cleaning solution, taking into account the treatment effect and resource utilization efficiency.

[0030] As shown in Figure 3 The process diagram provided by the pressure-flow rate coordinated cycle adjustment and reverse osmosis inlet parameter adjustment of the embodiment of the application is shown in FIG. 1. The first conductivity is obtained to divide the interval to adjust the step-up or step-down, and the permeation pressure difference is monitored in real time during the interval division process. The circulation flow rate adjustment and the double-stage reverse osmosis membrane inlet parameter adjustment are performed through the water production circulation adjustment, and the inlet preheating adjustment is performed during the inlet parameter adjustment process. The membrane stack electric field intensity is increased / decreased by obtaining the desalination index, and the backflow valve opening adjustment value is used to adjust the backflow flow rate.

[0031] Further, the pressure-flow rate collaborative control is performed on the pressure fine desalination process of the first reverse osmosis membrane, and the specific steps are as follows: based on the salt content in the first reverse osmosis membrane water inlet buffer tank, a first conductivity is obtained, and compared with a preset reverse osmosis conductivity interval: if the obtained first conductivity is greater than the maximum value of the preset reverse osmosis conductivity interval, an adjustment value of the pressure increasing step is obtained based on the upward deviation of the first conductivity, so as to increase the water pressure increasing range of the first reverse osmosis membrane, until the first conductivity is in the preset reverse osmosis conductivity interval; during the adjustment process of the water pressure, the water conductivity after the first reverse osmosis membrane is monitored in real time to obtain a second conductivity, if the water pressure is increased to the preset water production pressure, and the second conductivity is greater than the preset first reverse osmosis membrane second conductivity, the adjustment of the water pressure is suspended, and a water conductivity warning instruction is sent to troubleshoot the desalination failure; if the obtained first conductivity is less than the minimum value of the preset reverse osmosis conductivity interval, an adjustment value of the pressure decreasing step is obtained based on the downward deviation of the first conductivity, so as to decrease the water pressure decreasing range of the first reverse osmosis membrane, if the second conductivity is still less than the preset first reverse osmosis membrane second conductivity after the water pressure is decreased, it is indicated that the pressure decrease is effective, otherwise, it is prompted that the high-pressure pump is recalled to the water pressure corresponding to the water pressure before the water pressure is decreased, and the second conductivity represents the water production of the first conductivity after the water inlet passes through the first reverse osmosis membrane.

[0032] If the obtained first conductivity is in the preset reverse osmosis conductivity interval, it is indicated that the salt content of the first reverse osmosis membrane water inlet is stable, and the current water pressure of the first reverse osmosis membrane is maintained; during the adjustment process of the water pressure, the osmotic pressure difference between the water inlet and the water outlet is monitored in real time; if the membrane flux pressure deviation is greater than the preset membrane flux pressure deviation, and the water pressure is increased to the preset water production pressure, it is indicated that the pipeline is blocked, and based on the current obtained membrane flux pressure deviation, an increasing value of the water production circulation flow rate is obtained, so as to reduce the membrane flux pressure deviation and the osmotic pressure difference by increasing the pipeline flushing rate, the membrane flux pressure deviation represents the difference between the obtained water inlet pressure and the water outlet pressure; after the water production circulation flow rate is increased, the membrane flux pressure deviation is reacquired, and when the membrane flux pressure deviation is less than the preset membrane flux pressure deviation, the current water production circulation flow rate is maintained.

[0033] Specifically, the circulating flow rate is adjusted as follows: based on the obtained membrane surface water flow rate, the membrane surface flow rate-concentrated water backflow mapping relationship is inputted to obtain a concentrated water backflow rate adjustment value, so as to increase the concentrated water circulation amount, and the membrane surface water flow rate is reacquired. The membrane surface water flow rate and the membrane inside-outside pressure difference represent the membrane surface water flow rate and the membrane inside-outside pressure difference corresponding to the primary reverse osmosis membrane. If the reacquired membrane surface water flow rate is greater than the preset membrane surface water flow rate, based on the current obtained membrane inside-outside pressure difference, an adjustment value of the high-pressure pump frequency is obtained, so as to maintain the concentrated water flow and increase the membrane surface shear force. The concentrated water represents the water flow that does not pass through the primary reverse osmosis membrane. The membrane inside-outside pressure difference is the difference between the pressure inside the primary reverse osmosis membrane and the pressure outside the primary reverse osmosis membrane.

[0034] In the present embodiment, the preset reverse osmosis conductivity interval is a closed interval formed by the maximum and minimum values of the historical first conductivity in the historical pressure-flow rate cooperative control process. The first conductivity upper deviation represents the difference between the obtained first conductivity and the maximum value of the preset reverse osmosis conductivity interval. The first conductivity lower deviation represents the difference between the obtained first conductivity and the minimum value of the preset reverse osmosis conductivity interval. The adjustment value of the pressure increase / decrease step obtained through the first conductivity upper / lower deviation is that the obtained first conductivity upper / lower deviation is inputted into the high-pressure pump controller in the double-stage reverse osmosis device. The controller performs real-time adjustment of the pressure increase / decrease step through the pre-constructed conductivity-water pressure correspondence relationship. The conductivity-water pressure correspondence relationship is obtained based on the historical working condition data and pressure adjustment records of the double-stage reverse osmosis device. The preset water production pressure is represented by the result of summing and averaging the historical water production pressure in the historical pressure-flow rate cooperative control process. Based on the membrane flux pressure deviation, the increase value of the water production circulation flow rate is obtained. The mapping relationship between the membrane flux pressure deviation and the water production circulation flow rate adjustment value is constructed using a convolutional neural network algorithm. In the training stage, the historical membrane flux pressure deviation is taken as the input sample, and the corresponding water production circulation flow rate adjustment value is taken as the output sample. The convolutional neural network is trained and the parameters are optimized, so that the model can learn the nonlinear relationship between the pressure deviation and the flow rate adjustment. The preset membrane flux pressure deviation is represented by the result of summing and averaging the historical membrane flux pressure deviation in the historical pressure-flow rate cooperative control process. The membrane surface flow rate-concentrated water backflow mapping relationship is inputted with the membrane surface water flow rate and outputted with the concentrated water backflow rate adjustment value. The mapping relationship is obtained by training using a support vector regression algorithm. The preset membrane surface water flow rate is represented by the result of summing and averaging the historical membrane surface water flow rate in the historical pressure-flow rate cooperative control process. Based on the current obtained membrane inside-outside pressure difference, the adjustment value of the high-pressure pump frequency is obtained by adjusting the high-pressure pump frequency based on the pre-set pressure difference-frequency correspondence relationship through the high-pressure pump controller. The correspondence relationship is obtained based on the historical working condition records of the double-stage reverse osmosis device through data fitting.

[0035] The pressure adjustment and circulation flow rate control of the primary reverse osmosis membrane form a closed loop adaptation to the water quality change and system state, which can effectively balance the desalination effect, energy consumption control and membrane component protection, and avoid the operation imbalance caused by single parameter adjustment. By taking the salt content (first conductivity) in the primary reverse osmosis membrane inlet buffer tank as the core basis, and dynamically adjusting the water pressure after comparing with the preset interval, the waste of energy consumption caused by excessive pressure can be avoided, and the incomplete desalination caused by insufficient pressure can also be prevented; unqualified product water can be avoided from being continuously produced, and further damage to the membrane components under abnormal conditions can also be prevented.

[0036] During the pressure adjustment process, the osmotic pressure difference between the inlet and outlet and the membrane flux pressure deviation are monitored synchronously, without relying on high pressure to break through the blockage, which can reduce the damage to the inner wall of the pipeline, quickly reduce the pressure difference, restore the smoothness of the water flow, and avoid the risk of membrane pollution caused by uneven local pressure on the membrane surface due to blockage. In the circulation flow rate adjustment link, increasing the concentration water circulation amount can enhance the shear force on the membrane surface, timely flush the pollutants adhering to the membrane surface, and reduce the accumulation of membrane pollution; if the flow rate on the membrane surface exceeds the preset range, the high-pressure pump frequency is adjusted to maintain the concentration water flow, which can ensure that the shear force on the membrane surface is within a reasonable range, and avoid excessive energy consumption caused by high flow rate.

[0037] The primary reverse osmosis can be self-adapted according to the salt content of the inlet water, the quality of the product water, the pipeline state and the membrane surface conditions, which can not only ensure the stability of the product water quality, but also reasonably control the energy consumption under the premise of meeting the desalination demand, reduce the impact of pipeline blockage and membrane pollution on the system, prolong the stable operation period of the membrane components and the pipeline, reduce the frequency of shutdown maintenance caused by parameter imbalance or failure, and make the operation of the primary reverse osmosis link more stable, economical and reliable.

[0038] Further, the inlet water parameters of the reverse osmosis component are adjusted, and the specific process is as follows: based on the current first conductivity, a collaborative desalination index for quantifying the collaborative efficiency of the double-stage reverse osmosis membrane is obtained in combination with the third conductivity, and desalination comparison is performed; the third conductivity represents the conductivity of the product water corresponding to the inlet water of the first conductivity after passing through the double-stage reverse osmosis membrane; the specific process of desalination comparison is as follows: if the obtained collaborative desalination index is less than the minimum value of the preset collaborative desalination index interval, it indicates that the desalination is unqualified, and based on the deviation of the collaborative desalination index, an increasing step of the electric field intensity of the membrane stack is obtained to increase the membrane stack voltage until the electric field intensity is equal to the preset electric field intensity; during the adjustment of the electric field intensity, the conductivity in the primary reverse osmosis membrane inlet buffer tank and the operating temperature on the surface of the double-stage reverse osmosis membrane are monitored in real time; if the re-obtained collaborative desalination index is still greater than the maximum value of the preset primary reverse osmosis inlet salt content interval after the membrane stack voltage is increased, the inlet salt content is adjusted to reduce the inlet salt content corresponding to the primary reverse osmosis membrane.

[0039] If the obtained synergistic desalination index is greater than the preset maximum value of the synergistic desalination index interval, it indicates that desalination is effective, and a reduction step of the membrane stack electric field strength is obtained to reduce the membrane stack voltage, and a corresponding residual heat reduction amount due to the reduction of the electric field strength is obtained, and a reduction value of the inflow buffer tank flow is obtained to reduce the residual heat absorbed by the inflow, so that the operating temperature of the surface of the reverse osmosis component is within the working interval; if the obtained synergistic desalination index is within the preset synergistic desalination index interval, the current membrane stack electric field strength is maintained; the inflow salt content is adjusted, and the specific process is as follows: based on the first conductivity deviation, an increase value of the inflow reflux valve opening degree is obtained, and the inflow end is increased by increasing the return flow of the first reverse osmosis membrane to reduce the salt content of the inflow; if the temperature of the first reverse osmosis membrane effluent at the inflow end is lower than the temperature on the inflow end side, based on the inflow temperature deviation, a transfer amount of the residual heat stored in the heat conducting medium is obtained to compensate for the temperature deviation of the mixed inflow and improve the preheating effect.

[0040] In the embodiment, the preset synergistic desalination index interval is formed by the maximum and minimum values of the synergistic desalination index in the historical inflow parameter adjustment process, the synergistic desalination index deviation represents the difference between the obtained synergistic desalination index and the maximum / minimum value of the preset synergistic desalination index interval, and the increase / decrease step of the membrane stack electric field strength is obtained based on the Gradient Boosting Decision Tree (GBDT) regularization algorithm, the historical synergistic desalination index deviation is taken as the input, and the membrane stack electric field strength is taken as the output for training to obtain the preset electric field strength.

[0041] The corresponding residual heat reduction amount due to the reduction of the electric field strength is obtained, and the reduction value of the inflow buffer tank flow is obtained by using a deep neural network regression algorithm, taking the residual heat as the input and the inflow buffer tank flow as the output for training, and similarly, the increase value of the inflow reflux valve opening degree is also obtained based on the algorithm, taking the first conductivity deviation as the input and the inflow reflux valve opening degree adjustment value as the output for training, and based on the inflow temperature deviation, the transfer amount of the residual heat stored in the heat conducting medium is obtained by inputting the obtained inflow temperature deviation into the heat energy controller in the two-stage reverse osmosis device, and the controller adjusts the preheating transfer amount through the preset temperature deviation-heat transfer corresponding relationship, and the preset temperature deviation-heat transfer corresponding relationship is obtained by data fitting based on the historical heat energy controller associated inflow temperature deviation and residual heat transfer amount working condition data, and the inflow temperature deviation represents the deviation between the water temperature before the inflow reflux and the water temperature after the inflow reflux.

[0042] The expression of the synergistic desalination index S is: , wherein C1 represents the first conductivity, C3 represents the third conductivity, C0 represents the historical average effective value of the first conductivity, a represents a very small positive number, and the denominator is prevented from being 0 when C3 approaches 0, in actual application, a can be ignored because C3 will not be 0 in reality, the formula is corrected by an anti-interference correction term and a purification term, and the stability and quality of desalination are considered at the same time, and the synergistic desalination efficiency of the two-stage reverse osmosis membrane is more comprehensively quantified, in the front part of the formula, the historical average effective value of the first conductivity is used to measure the deviation of the current feed water from the historical normal state, the denominator is used to correct the feed water fluctuation, the desalination effect is prevented from being misjudged due to the increase in the salt content of the feed water itself, and the accuracy in the stable working condition is also ensured; the second part of the formula reflects the purification capacity of the two-stage reverse osmosis, and the purification multiple is reflected by the ratio.

[0043] Through dynamic adjustment of the feed water parameters of the reverse osmosis assembly, multi-dimensional optimization of the synergistic desalination efficiency, energy consumption control and operation stability of the two-stage reverse osmosis membrane is realized, and system operation problems caused by desalination imbalance, energy waste or temperature abnormalities are avoided. First, the synergistic desalination index relates the salt content of the first-stage reverse osmosis feed water to the water quality of the second-stage reverse osmosis product water, can accurately quantify the overall desalination synergistic effect of the two-stage membrane, and breaks away from the one-sidedness of relying on a single membrane parameter for judgment, so that the evaluation of the desalination effect is more in line with the actual operation state of the system, and provides a precise basis for subsequent parameter adjustment.

[0044] In terms of desalination effect optimization, when the synergistic desalination index does not meet the standard, the ion migration driving force is increased by gradually increasing the membrane stack electric field strength to strengthen the desalination capacity of the two-stage membrane, and ensure that the product water quality approaches the qualified range; the salt content of the first-stage reverse osmosis feed water is reduced by feed water reflux, the desalination load of the membrane stack is reduced from the source, the membrane stack is prevented from being in a high-load operation state for a long time due to too high salt content of the feed water, and the loss of the membrane assembly caused by excessive desalination is effectively reduced. When the synergistic desalination index is better than expected, the membrane stack electric field strength is appropriately reduced, unnecessary energy consumption is reduced, the feed water buffer tank flow is adjusted according to the residual heat at the same time, the membrane surface temperature is prevented from being abnormal due to the excessive absorption of residual heat by the feed water, the reverse osmosis assembly is ensured to always operate in the appropriate temperature range, and the temperature fluctuation is prevented from affecting the water permeability and desalination performance of the membrane.

[0045] In addition, the compensation design of the feed water temperature deviation balances the mixed feed water temperature by using the electric field residual heat, not only improves the preheating effect of the feed water, prevents the membrane flux from being reduced due to low-temperature feed water, but also realizes the resource utilization of the residual heat, and further optimizes the energy consumption structure of the system. The reverse osmosis assembly can dynamically adapt the electric field strength, the salt content and the temperature of the feed water according to the desalination effect, ensures the stable and standard product water quality, reasonably controls the energy consumption on the premise of meeting the desalination demand, reduces the adverse effects of temperature, salt content and other factors on the membrane assembly, prolongs the service life of the membrane, and improves the economy and reliability of the entire reverse osmosis system operation.

[0046] The equipment of the reverse osmosis pure water production method based on two-stage membrane assembly collaborative purification provided by the embodiment of the application comprises a preliminary filter device, a precision filter device, a fresh water adjusting device and a two-stage reverse osmosis device. The preliminary filter device comprises a preliminary filter for preliminary filtering raw water and a flow meter for detecting flow and flow rate. The precision filter device comprises a precision filter for closely filtering water after preliminary filtering, a flow sensor for detecting flow and flow rate, and a turbidity sensor for detecting solid particle content of water. The fresh water adjusting device comprises a flow sensor for detecting flow at the inlet and outlet of the fresh water chamber, a voltage sensor for detecting voltage value of electrolytic adjustment in the fresh water chamber, a pH sensor for detecting pH value before and after fresh water adjustment, and a conductivity sensor for detecting salt content of water in the buffer tank. The two-stage reverse osmosis device comprises a flow sensor for detecting flow and flow rate of the first-stage reverse osmosis membrane and the second-stage reverse osmosis membrane, a pressure sensor for detecting pressure deviation of water pressure and membrane flux pressure of the two-stage reverse osmosis membrane, and a conductivity sensor for detecting conductivity of water inlet and water outlet of the two-stage reverse osmosis membrane.

[0047] In the embodiment, raw water flows through the preliminary filter device, the precision filter device, the fresh water adjusting device and the two-stage reverse osmosis device in sequence. In the preliminary filter device, the preliminary filter preliminarily filters raw water, and the flow meter monitors flow and flow rate during filtering. Then, water flows to the precision filter device, the precision filter performs fine filtering, the flow sensor and the turbidity sensor monitor flow rate and solid particle content of water, respectively, to ensure filtering accuracy. Next, water enters the fresh water adjusting device, the flow sensor monitors flow at the inlet and outlet of the fresh water chamber, the voltage sensor detects electrolytic adjustment voltage, the pH sensor detects pH before and after adjustment, and the conductivity sensor detects salt content of water in the buffer tank to adjust water quality parameters. Then, water enters the two-stage reverse osmosis device, the flow sensor monitors flow and flow rate of the first-stage and second-stage reverse osmosis membranes, the pressure sensor monitors water pressure and membrane flux pressure deviation, and the conductivity sensor monitors conductivity of water inlet and water outlet, to realize two-stage membrane collaborative purification. The devices are connected in series through pipelines, and the sensors monitor parameters in real time to provide basis for regulation and control of each link, thereby ensuring continuity and water quality stability of pure water production.

[0048] The above-described embodiments can be implemented in whole or in part by software, hardware (such as a circuit), firmware, or any combination thereof. When implemented in software, the above-described embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions according to the embodiments of the present application are wholly or partially generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center through a wired (for example, infrared, wireless, microwave, etc.) manner. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server, data center, etc. containing one or more available medium collections. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state disk.

[0049] It should be understood that the term "and / or" herein merely describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B can represent three cases of A alone, A and B together, and B alone, where A and B can be singular or plural. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects, but can also represent an "and / or" relationship, which can be understood in the context before and after.

[0050] In the present application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or the like means any combination of the items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0051] It should be understood that in various embodiments of the present application, the size of the sequence number of the above-described processes does not mean the order of execution, and the execution order of the processes should be determined by their functions and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0052] Those skilled in the art can clearly understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0053] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the devices, apparatuses and units described above can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0054] In several embodiments provided by the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, for example, the division of units is only a logical function division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0055] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0056] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit.

[0057] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0058] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for producing pure water by reverse osmosis based on the synergistic purification of a two-stage membrane module, characterized in that, The method comprises the following steps: Step one, in the water quality monitoring stage after pretreatment, the desalination process of the reverse osmosis assembly is preliminarily optimized based on the obtained ion migration state data, so as to reduce the scaling rate on the surface of the reverse osmosis membrane, the preliminary water inlet optimization includes ion membrane switching and cleaning state control, and the reverse osmosis assembly includes a fresh water chamber containing an ion exchange membrane, a first reverse osmosis membrane and a second reverse osmosis membrane; Step two, based on the salt content of the water inlet at the corresponding water inlet of the first reverse osmosis membrane after the preliminary water inlet optimization, the pressure-flow rate collaborative control of the pressure precision desalination process of the first reverse osmosis membrane is performed, and the circulating flow rate is adjusted at the same time, so as to reduce the deposition of residual pollutants on the membrane surface; Step three, based on the conductivity of the corresponding specified position in the first reverse osmosis membrane water inlet buffer tank and the feedback state of the second reverse osmosis membrane water quality, the water inlet parameters of the reverse osmosis assembly are adjusted, so as to reduce the concentration polarization and membrane pollution caused by the water inlet flow rate at the water inlet of the first reverse osmosis membrane, and the water inlet parameters include electric field intensity and water inlet salt content.

2. The method according to claim 1, wherein the method is characterized by, The preliminary water inlet optimization of the desalination process of the reverse osmosis assembly is specifically as follows: According to the initial pH value in the fresh water chamber, the preliminary water inlet classification is performed, specifically as follows: The first type, if the initial pH value in the fresh water chamber is greater than the maximum value of the preset water inlet interval, the anion migration state in the fresh water chamber is monitored, and a cation membrane switching instruction is sent to prompt a preset personnel to check the current ion exchange membrane, so as to reduce the pH value of the water inlet in the fresh water chamber; If the current fresh water chamber is in a cation migration state, the electric field intensity increase value is obtained based on the current cation migration rate, so as to enhance the migration efficiency of the cation; The second type, if the initial pH value in the fresh water chamber is within the preset water inlet interval, it indicates that the working state of the first reverse osmosis membrane is qualified, and the current pH value is maintained; The third type, if the initial pH value in the fresh water chamber is less than the minimum value of the preset water inlet interval, the cation migration state in the fresh water chamber is monitored, and a negative membrane switching instruction is sent to prompt a preset personnel to check the current ion exchange membrane, so as to improve the pH value of the water inlet in the fresh water chamber; If the current fresh water chamber is in an anion migration state, the voltage increase value of the ion exchange membrane on both sides is obtained based on the current anion migration rate, so as to enhance the driving force of the electric field on the ion; After the ion migration state monitoring in the fresh water chamber, the pH value monitoring of the fresh water chamber outlet is performed.

3. The method according to claim 2, wherein the method is characterized by, The pH value monitoring of the fresh water chamber outlet is specifically as follows: If the pH value at the outlet of the fresh water chamber is greater than the maximum value of the preset water inlet interval, the outlet pH value upper deviation is input into the RO optimal-electrolysis voltage mapping relationship to obtain the electrolysis voltage increase value in the fresh water chamber, so as to increase the migration rate of the anion to the acid chamber, and the outlet pH value upper deviation represents the difference between the obtained pH value at the outlet of the fresh water chamber and the maximum value of the preset water inlet interval. If the pH value at the outlet of the fresh water chamber is less than the minimum value of the preset water inlet interval, the pH value deviation at the outlet is input into the RO optimal-electrolysis voltage mapping relationship to obtain a decrease value of the electrolysis voltage in the fresh water chamber, so as to reduce the migration rate of cations to the alkali chamber. The pH value deviation at the outlet represents the difference between the obtained pH value at the outlet of the fresh water chamber and the minimum value of the preset water inlet interval. If the pH value at the outlet of the fresh water chamber is within the preset water inlet interval, the current electrolysis voltage is maintained, and the fresh water chamber inlet flow rate is matched with the electrolysis voltage. Specifically, if the current electrolysis voltage is increased relative to the set electrolysis voltage, the running speed of the water inlet variable frequency pump is reduced according to the preset voltage-flow rate matching curve, so as to prolong the ion hydraulic retention time by reducing the flow rate. If the current electrolysis voltage is reduced relative to the set electrolysis voltage, the running speed of the water inlet variable frequency pump is increased according to the preset voltage-flow rate matching curve, so as to reduce the hydraulic retention time by increasing the flow rate. The voltage-flow rate matching curve is used to visualize the mapping relationship between the corresponding electrolysis voltage and the water inlet flow rate in the electrolytic water treatment process. When the electrolysis voltage is adjusted, the adjustment value of the water inlet flow rate is obtained through the curve. The cleaning state control includes ion exchange membrane cleaning state control for improving electrolysis efficiency and reverse osmosis membrane cleaning state control for improving reverse osmosis efficiency. Specifically, the ion exchange membrane cleaning state control includes the following steps:

4. The method according to claim 1, wherein the method is characterized by, The ion exchange membrane cleaning state control includes the following steps: The pH value at the outlet of the fresh water chamber corresponding to the ion exchange membrane in the cleaning tank is monitored in real time. If the pH value at the outlet of the fresh water chamber is not within the preset outlet interval, the outlet pH value deviation is input into the ion outlet-circulation time mapping relationship to obtain a decrease value of the desalination flow rate circulation cycle, so as to reduce the subsequent corresponding fouling efficiency. The reverse osmosis membrane cleaning state control includes the following steps: Based on the cleaning solution concentration deviation after the ion exchange membrane cleaning state control, an adjustment value of the circulation flow rate of the double-stage reverse osmosis membrane is obtained to reduce the fouling probability on the surface of the double-stage reverse osmosis membrane. The double-stage reverse osmosis membrane includes a primary reverse osmosis membrane and a secondary reverse osmosis membrane. The cleaning solution concentration deviation reflects the cleaning degree of the double-stage reverse osmosis membrane. If the cleaning solution concentration after the reverse osmosis membrane cleaning state control is greater than the preset cleaning solution concentration, a backflow instruction is sent to reuse the cleaning solution. Otherwise, a cleaning solution waste instruction is sent to discharge the cleaning solution to waste water treatment. The cleaning solution concentration includes cleaning acid solution and cleaning alkali solution. The pressure-flow rate collaborative control of the pressure precision desalination process of the primary reverse osmosis membrane includes the following steps:

5. The method according to claim 1, wherein the method is characterized by: Based on the salt content in the primary reverse osmosis membrane water inlet buffer tank, a first conductivity is obtained and compared with the preset reverse osmosis conductivity interval. If the obtained first conductivity is greater than the maximum value of the preset reverse osmosis conductivity interval, an adjustment value of the pressure increase step is obtained based on the first conductivity deviation to increase the water pressure of the primary reverse osmosis membrane until the first conductivity is within the preset reverse osmosis conductivity interval. ​ In the process of adjusting the water pressure, the conductivity of the produced water after passing through the first reverse osmosis membrane is monitored in real time to obtain a second conductivity. If the water pressure is increased to a preset produced water pressure and the second conductivity is greater than a preset second conductivity of the first reverse osmosis membrane, the adjustment of the water pressure is suspended, and a water conductivity warning instruction is sent to troubleshoot the desalination failure. If the obtained first conductivity is less than the minimum value of the preset reverse osmosis conductivity interval, an adjustment value of the pressure reduction step is obtained based on the first conductivity deviation to reduce the water pressure reduction amplitude of the first reverse osmosis membrane. If the second conductivity is still less than the preset second conductivity of the first reverse osmosis membrane after the water pressure is reduced, it indicates that the pressure reduction is effective. Otherwise, the high-pressure pump is prompted to return to the water pressure before the water pressure is reduced. The second conductivity represents the conductivity of the produced water corresponding to the first conductivity.

6. The method according to claim 5, wherein the method is characterized by, The comparison with the preset reverse osmosis conductivity interval further includes: If the obtained first conductivity is within the preset reverse osmosis conductivity interval, it indicates that the salt content of the water inlet of the first reverse osmosis membrane is stable, and the current water pressure of the first reverse osmosis membrane is maintained. In the process of adjusting the water pressure, the osmotic pressure difference between the water inlet and the produced water outlet is monitored in real time. If the membrane flux pressure deviation is greater than the preset membrane flux pressure deviation and the water pressure is increased to a preset produced water pressure, it indicates that the pipeline is blocked. Based on the currently obtained membrane flux pressure deviation, an increase value of the produced water circulation flow rate is obtained to reduce the membrane flux pressure deviation and the osmotic pressure difference by increasing the pipeline flushing rate. The membrane flux pressure deviation represents the difference between the pressure at the water inlet and the pressure at the produced water outlet. After the produced water circulation flow rate is increased, the membrane flux pressure deviation is reacquired. When the membrane flux pressure deviation is less than the preset membrane flux pressure deviation, the current produced water circulation flow rate is maintained.

7. The method according to claim 6, wherein the method is characterized by, The specific process of adjusting the circulation flow rate is: Based on the obtained membrane surface water flow rate, the membrane surface flow rate-concentrated water backflow mapping relationship is input to obtain a concentrated water backflow rate adjustment value to increase the concentrated water circulation amount, and the membrane surface water flow rate is reacquired. The membrane surface water flow rate and the membrane internal and external pressure difference represent the membrane surface water flow rate and the membrane internal and external pressure difference corresponding to the first reverse osmosis membrane. If the reacquired membrane surface water flow rate is greater than the preset membrane surface water flow rate, an adjustment value of the high-pressure pump frequency is obtained based on the currently obtained membrane internal and external pressure difference to maintain the concentrated water flow and improve the membrane surface shear force. The concentrated water represents the water flow that does not pass through the first reverse osmosis membrane. The membrane internal and external pressure difference is the difference between the internal pressure of the first reverse osmosis membrane and the external pressure of the first reverse osmosis membrane.

8. The method according to claim 1, wherein the method is characterized by, The specific process of adjusting the water inlet parameters of the reverse osmosis assembly is: Based on the first conductivity and the third conductivity, a synergy desalination index for quantifying the synergy efficiency of the double-stage reverse osmosis membrane is obtained, and desalination comparison is performed. The third conductivity represents the conductivity of the produced water corresponding to the water inlet of the first conductivity passing through the double-stage reverse osmosis membrane. The specific process of the desalination comparison is: If the obtained synergistic desalination index is less than the preset minimum value of the synergistic desalination index interval, it indicates that the desalination is unqualified, and based on the deviation of the synergistic desalination index, an increase step of the electric field intensity of the membrane stack is obtained to increase the membrane stack voltage until the electric field intensity is equal to the preset electric field intensity; In the adjustment process of the electric field intensity, the conductivity in the primary reverse osmosis membrane inlet water buffer tank and the operating temperature on the surface of the double-stage reverse osmosis membrane are monitored in real time, and if the re-obtained synergistic desalination index is still less than the preset minimum value of the primary reverse osmosis inlet water salinity interval after the membrane stack voltage is increased, the inlet water salinity adjustment is performed to reduce the corresponding inlet water salinity of the primary reverse osmosis membrane.

9. The method according to claim 8, wherein the method is characterized by, The desalination comparison further includes: If the obtained synergistic desalination index is greater than the preset maximum value of the synergistic desalination index interval, it indicates that the desalination is effective, and a decrease step of the electric field intensity of the membrane stack is obtained to reduce the membrane stack voltage, and a corresponding residual heat reduction amount due to the reduction of the electric field intensity is obtained in synchronization, a decrease value of the inlet water buffer tank flow is obtained to reduce the residual heat absorbed by the inlet water, so that the operating temperature on the surface of the reverse osmosis assembly is within the working interval; If the obtained synergistic desalination index is within the preset synergistic desalination index interval, the current electric field intensity of the membrane stack is maintained; The inlet water salinity adjustment specifically includes: based on the first conductivity deviation, an increase value of the inlet water reflux valve opening degree is obtained, and the primary reverse osmosis membrane outlet flow is increased to the inlet end to reduce the inlet water salinity thereof; If the primary reverse osmosis membrane outlet water temperature at the inlet end reflux is lower than the temperature on the inlet end side, based on the inlet water temperature deviation, a transfer amount of the electric field residual heat stored in the heat conduction medium is obtained to compensate for the temperature deviation of the mixed inlet water and improve the preheating effect.

10. An apparatus for producing pure water by reverse osmosis using the method according to any one of claims 1 to 9, comprising: A preliminary filter device, a precision filter device, a fresh water adjusting device, and a double-stage reverse osmosis device; The preliminary filter device includes a preliminary filter for performing preliminary filtration on raw water, and a flow meter for detecting flow and flow rate; The precision filter device includes a precision filter for performing close filtration on the water after preliminary filtration, a flow sensor for detecting flow and flow rate, and a turbidity sensor for detecting solid particle content of the water body; The fresh water adjusting device includes a flow sensor for detecting flow at the inlet and outlet of the fresh water chamber, a voltage sensor for detecting voltage value of electrolytic adjustment in the fresh water chamber, a pH sensor for detecting pH value before and after fresh water adjustment, and a conductivity sensor for detecting salinity of water in the buffer tank; The double-stage reverse osmosis device includes a flow sensor for detecting flow and flow rate corresponding to the primary reverse osmosis membrane and the secondary reverse osmosis membrane, a pressure sensor for detecting water pressure and membrane flux pressure deviation of the double-stage reverse osmosis membrane, and a conductivity sensor for detecting conductivity of inlet water and product water of the double-stage reverse osmosis membrane.

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