Single-stage multi-section treatment system and method for seawater desalination and boron removal

Abstract

The application discloses a single-stage multi-section treatment system and method for seawater desalination and boron removal, relates to the technical field of seawater desalination and boron removal, and realizes the pretreatment and first desalination and boron removal of seawater raw water through a single-stage process, cooperates with a pressure exchanger to realize the efficient recovery of the energy of high-pressure concentrated water and the pressurization of low-pressure inlet water, reduces the operation load of a high-pressure pump of a first stage, and realizes the effective reduction of energy consumption; gradient reverse osmosis treatment is performed on single-stage produced water through a multi-section process, the step-by-step pressurization and pressure compensation of high-pressure pumps of all stages on concentrated water of previous sections are utilized, the residual pressure of concentrated water is fully utilized, the gradient reprocessing and deep boron removal of concentrated water are realized, and the overall recovery rate of seawater desalination is improved. In addition, a control unit dynamically determines the optimal operation section number of the multi-section process according to actual inlet water quality and produced water targets, accurately adjusts the pressure of high-pressure pumps of all stages and the start-stop state of membrane assemblies, makes system operation parameters highly adapt to actual working conditions, and avoids the problems of excessive treatment or insufficient treatment caused by fixed section number operation.

Description

Technical Field

[0001] This application relates to the field of boron removal technology in seawater desalination, and in particular to a single-stage multi-stage treatment system and method for boron removal in seawater desalination. Background Technology

[0002] With the increasing severity of global freshwater scarcity, seawater desalination has become a key technological pathway to ensure water security. Among these, reverse osmosis (RO) technology has become the mainstream desalination method due to its relatively low energy consumption and mature process. Currently, the core separation layer of RO systems commonly uses transmembrane composite (TFC) polyamide membranes. These membranes are widely recognized as the "gold standard" in membrane treatment due to their excellent water flux and extremely high rejection rates for monovalent salts (e.g., the rejection rate for sodium chloride can typically be consistently above 99%). However, although TFC membranes perform excellently in treating common ionic salts, boric acid (H3BO3) is electroneutrally neutral under neutral pH conditions, and its effective molecular size is smaller than that of common hydrated ions (such as Na+). + K + Its size allows it to easily penetrate the microporous structure of the polyamide active layer, severely limiting the retention effect of conventional reverse osmosis membranes. Therefore, how to efficiently remove residual boron from seawater remains a persistent technical challenge in this field.

[0003] Traditional reverse osmosis processes often employ a fixed "two-stage reverse osmosis" architecture, which faces bottlenecks such as rigid configuration, high energy consumption from full-volume pressurization of the first-stage feed water, and a sharp decline in system retention efficiency due to concentration polarization when increasing water recovery rates. Furthermore, in practical engineering, feed water quality and membrane degradation are dynamic, making it difficult to maintain a fixed number of stages within the optimal operating window. Faced with complex and variable operating conditions, this often results in low operating efficiency or substandard product water.

[0004] In summary, existing technologies urgently need a high recovery rate solution that can break through the constraints of traditional fixed configurations, dynamically determine the number of operating stages through intelligent algorithms, and decouple energy demand from boron removal performance. Summary of the Invention

[0005] To address the above problems, this application provides a single-stage multi-stage treatment system and method for boron removal in seawater desalination, comprising the following: In a first aspect, this application provides a single-stage, multi-stage treatment system for boron removal in seawater desalination, the system comprising: A single-stage process and a multi-stage process are connected in sequence, a control unit connected to the single-stage process and the multi-stage process, and a product water pipeline connected to the multi-stage process; The single-stage process includes a pretreatment module, a first-stage high-pressure pump, a pressure exchanger, a single-stage reverse osmosis membrane module, and a first concentrate discharge pipeline. The single-stage process pretreats the seawater raw water through the pretreatment module, performs the first reverse osmosis desalination and boron removal on the pretreated seawater through the first-stage high-pressure pump and the single-stage reverse osmosis membrane module, recovers the energy of the high-pressure concentrate through the pressure exchanger, completes the low-pressure feed water pressurization, and outputs the first-stage product water to the multi-stage process. The multi-stage process includes a secondary high-pressure pump, a tertiary high-pressure pump, and up to an n+1th high-pressure pump, n reverse osmosis membrane modules connected in series, and a second concentrate discharge pipeline, where n is an integer greater than or equal to 2; the multi-stage process is used to receive the first-stage permeate output from the single-stage process, and to stepwise pressurize the concentrate from the preceding stage through each stage of high-pressure pumps, and then send the pressurized concentrate to the next stage of reverse osmosis membrane module for reverse osmosis boron removal; The control unit is used to acquire influent water quality parameters and product water quality targets, determine the optimal number of operating segments in the multi-stage process, and adjust the operating pressure of the first-stage high-pressure pump in the single-stage process, the operating pressure of each stage of the high-pressure pump in the multi-stage process, and the start-up and shutdown status of the reverse osmosis membrane module. The product water pipeline is used to collect the product water output from the multi-stage process and transport it externally.

[0006] Optionally, the control unit is signal-connected to the single-stage process and the multi-stage process, and the control unit has a built-in stage number decision algorithm and concentration prediction model.

[0007] Optionally, the segment number decision algorithm uses the boron concentration in the produced water reaching a preset standard as a constraint to find the optimal number of operating segments n for the multi-segment process that minimizes the energy consumption per unit of produced water or maximizes the total recovery rate.

[0008] Optionally, the concentration prediction model is based on the principle of mass conservation and combines the system influent flow rate, single-stage process recovery rate, multi-stage process recovery rate and membrane module removal rate to calculate the total recovery rate and total effluent concentration of the system.

[0009] Optionally, the pressure exchanger is connected to the low-pressure inlet of the first-stage high-pressure pump and the concentrate outlet of the single-stage reverse osmosis membrane module, respectively; the pressure exchanger is used to receive the high-pressure concentrate discharged from the single-stage reverse osmosis membrane module and transfer the pressure energy of the high-pressure concentrate to the low-pressure inlet entering the pressure exchanger.

[0010] Optionally, in the n-segment reverse osmosis membrane modules connected in series, the concentrate end of the i-th segment reverse osmosis membrane module is connected to the inlet end of the (i+2)-th stage high-pressure pump, and after pressure compensation by the (i+2)-th stage high-pressure pump, it is connected to the inlet end of the (i+1)-th segment reverse osmosis membrane module, where i = 1, 2, ..., n-1; the product water end of each segment reverse osmosis membrane module is connected to the product water pipeline.

[0011] Secondly, this application provides a single-stage, multi-stage treatment method for boron removal in seawater desalination, the method comprising: Obtain seawater influent quality parameters and product water quality targets; The optimal number of running segments n for a multi-segment process is determined by the control unit; After the raw seawater is pretreated by a single-stage pretreatment module, it is then desalinated and debored by reverse osmosis for the first time in a single-stage process to output primary product water. The primary product water is then sent to a multi-stage process with the corresponding optimal operating stage for gradient reverse osmosis deboring. Real-time monitoring of the product water quality of multiple processes and dynamic adjustment of the operation status of single-stage and multi-stage processes; The permeate from multiple stages of the process is collected to complete the desalination and boron removal of seawater.

[0012] Optionally, determining the optimal number of operating segments n for the multi-segment process through the control unit includes: By using the segment number decision algorithm built into the control unit, and taking the boron concentration in the produced water reaching a preset standard as a constraint, the optimal number of operating segments n for the multi-stage process is obtained, which minimizes the energy consumption per unit of produced water or maximizes the total recovery rate. Here, n is an integer greater than or equal to 2.

[0013] Optionally, the real-time monitoring of the product water quality of multiple processes and the dynamic adjustment of the operating status of single-stage and multi-stage processes include: The total recovery rate and total effluent concentration of the system are calculated by the concentration prediction model built into the control unit. Combined with the product water quality monitoring data, the operating pressure of the first-stage high-pressure pump in the single-stage process, the operating pressure of each stage of the high-pressure pump in the multi-stage process, and the start-up and shutdown status of the reverse osmosis membrane module are adjusted.

[0014] Optionally, the step of sending the primary permeate into a multi-stage process corresponding to the optimal operating stage for gradient reverse osmosis boron removal includes: After the primary permeate is sent into the multi-stage process, the concentrate produced by the i-th stage reverse osmosis membrane module is pressurized by the (i+2)-th stage high-pressure pump and then sent into the (i+1)-th stage reverse osmosis membrane module for boron removal, where i = 1, 2, ..., n-1.

[0015] Optionally, during the initial reverse osmosis desalination and boron removal process of the single-stage reverse osmosis membrane module after pressurization by the first-stage high-pressure pump, the energy of the high-pressure concentrate discharged from the single-stage reverse osmosis membrane module is recovered through a pressure exchanger. The pressure energy of the high-pressure concentrate is transferred to the low-pressure feed water entering the pressure exchanger, thereby pressurizing the low-pressure feed water before it is sent to the first-stage high-pressure pump.

[0016] Optionally, in the gradient reverse osmosis boron removal process, the permeate from each section of the reverse osmosis membrane module is collected into the permeate pipeline through its permeate end, and the permeate from multiple stages is collected and transported outward by the permeate pipeline.

[0017] Thirdly, this application provides an apparatus comprising a memory and a processor, the memory for storing instructions or code, and the processor for executing the instructions or code to cause the apparatus to perform the single-stage multi-stage desalination and boron removal method for seawater as described in any of the implementations of the second aspect.

[0018] Fourthly, this application provides a computer-readable storage medium storing code, wherein when the code is executed, a device executing the code implements the single-stage multi-stage treatment method for boron removal in seawater desalination as described in any of the implementations of the second aspect above.

[0019] This application provides a single-stage, multi-stage seawater desalination system for boron removal. A single-stage process first pre-treats the raw seawater and performs initial desalination and boron removal. Combined with a pressure exchanger for efficient energy recovery from the high-pressure concentrate and pressurization of the low-pressure feedwater, this significantly reduces the operating load on the first-stage high-pressure pump, effectively reducing energy consumption from the system's front end. Simultaneously, a multi-stage process performs gradient reverse osmosis treatment on the single-stage permeate. Utilizing the stepwise pressurization and supplemental pressurization of the concentrate by each stage of high-pressure pumps, the residual pressure of the concentrate is fully utilized, achieving gradient re-treatment and deep boron removal, effectively improving the overall seawater desalination recovery rate. Furthermore, the control unit dynamically determines the optimal number of operating stages based on the actual feedwater quality and permeate target, and precisely adjusts the pressure of each stage of high-pressure pump and the start / stop status of the membrane modules, ensuring that the system operating parameters are highly adapted to actual operating conditions and avoiding over-treatment or under-treatment problems caused by operating with a fixed number of stages. This system achieves dual optimization of energy consumption and recovery rate while ensuring that the boron concentration in the produced water meets the standards and the desalination effect is stable. It breaks through the technical bottlenecks of traditional seawater desalination boron removal processes, which are characterized by rigid configuration, low energy efficiency, and limited recovery rate. It achieves the technical effects of low energy consumption, high recovery rate, stable water quality compliance, and strong adaptability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings used in the description of the embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This application provides a single-stage, multi-stage seawater desalination and boron removal system as an embodiment of the present application. Figure 2 Another single-stage multi-stage treatment system for boron removal in seawater desalination provided in this application embodiment; Figure 3 This is a flowchart of a single-stage, multi-stage treatment method for boron removal in seawater desalination, provided as an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0024] This embodiment provides a single-stage multi-stage treatment system for boron removal in seawater desalination. By integrating single-stage and multi-stage processes and combining them with a control unit containing a built-in intelligent algorithm, the system achieves the dual goals of meeting water quality standards and reducing energy consumption during the boron removal process in seawater desalination. The composition, functions of each part, and operation process of the system are described in detail below.

[0025] Figure 1 This application provides a single-stage, multi-stage seawater desalination and boron removal system, combined with... Figure 1 As shown, the system includes: A single-stage process and a multi-stage process are connected in sequence, a control unit that is signal-connected to both the single-stage process and the multi-stage process, and a product water pipeline 12 connected to the multi-stage process. The product water pipeline is used to collect the product water output from the multi-stage process and transport it outward.

[0026] The single-stage process includes a pretreatment module 1, a first-stage high-pressure pump 2, a pressure exchanger 3, and a single-stage reverse osmosis membrane module 4 connected in sequence, and the single-stage reverse osmosis membrane module 4 is also connected to a first concentrate discharge pipeline 5.

[0027] The pretreatment module 1 is used to pretreat the raw seawater, removing impurities to ensure it meets the feed water requirements of the subsequent reverse osmosis membrane module. In this application, the pretreatment module 1 includes one, more, or a combination of coagulation sedimentation, multi-media filters, activated carbon filters, microfiltration, and ultrafiltration. The primary high-pressure pump 2 provides pressure power for the single-stage reverse osmosis process, pressurizing the pretreated low-pressure seawater to the operating pressure of the single-stage reverse osmosis membrane module 4, meeting the pressure requirements for reverse osmosis desalination and boron removal.

[0028] The pressure exchanger 3 is connected to the low-pressure inlet of the first-stage high-pressure pump 2 and the concentrate outlet of the single-stage reverse osmosis membrane module 4, respectively. As an energy recovery device, it is used to receive the high-pressure concentrate discharged from the single-stage reverse osmosis membrane module 4 and transfer the pressure energy of the high-pressure concentrate to the low-pressure inlet of the pressure exchanger 3, thereby reducing the load on the first-stage high-pressure pump 2 and saving system energy consumption.

[0029] The single-stage reverse osmosis membrane module 4 is the core separation unit of the single-stage process. It performs the first reverse osmosis desalination and boron removal treatment on the pressurized seawater, separating primary permeate and high-pressure concentrate. The primary permeate is sent to the multi-stage process for further treatment. Part of the high-pressure concentrate enters the pressure exchanger 3 for energy recovery, and the other part is discharged from the system through the first concentrate discharge pipeline 5. The first concentrate discharge pipeline 5 provides a discharge channel for the concentrate of the single-stage process, avoiding the accumulation of concentrate in the single-stage process and affecting the treatment effect.

[0030] The specific operation flow of the single-stage process is as follows: After the seawater is pretreated by the pretreatment module 1, part of it enters the first-stage high-pressure pump 2 for pressurization, and the other part enters the pressure exchanger 3 to receive the pressure energy of the high-pressure concentrate to achieve pressurization. The two pressurized seawaters are mixed and enter the single-stage reverse osmosis membrane module 4. After reverse osmosis desalination and boron removal, first-stage permeate and high-pressure concentrate are produced. The first-stage permeate is transported to the multi-stage process. After the high-pressure concentrate completes energy recovery through the pressure exchanger 3, part of it is discharged through the first concentrate discharge pipeline 5.

[0031] The multi-stage process includes a reverse osmosis membrane array (n≥2) consisting of n stages connected in series, a secondary high-pressure pump 6, a tertiary high-pressure pump 8, an n+1 stage high-pressure pump 10, and a second concentrate discharge pipeline 13. The reverse osmosis membrane array specifically includes a first-stage reverse osmosis membrane module 7, a second-stage reverse osmosis membrane module 9, and an nth-stage reverse osmosis membrane module 11.

[0032] This multi-stage process employs a gradient reprocessing logic. It receives the first-stage permeate from the single-stage process and uses a series of high-pressure pumps, from the second-stage high-pressure pump 6 to the third-stage high-pressure pump 8 to the n+1 stage high-pressure pump 10, to progressively pressurize the concentrate from the preceding stage. The pressurized concentrate is then sent to the next stage of the reverse osmosis membrane module for boron removal. The permeate from each stage of the reverse osmosis membrane module is collected in the permeate pipeline 12, and finally, the concentrate is discharged from the system through the second concentrate discharge pipeline 13.

[0033] In a reverse osmosis membrane array with n segments connected in series, the concentrate end of the i-th reverse osmosis membrane module is connected to the inlet of the (i+2)-th stage high-pressure pump. After pressure compensation by the (i+2)-th stage high-pressure pump, it is connected to the inlet of the (i+1)-th stage reverse osmosis membrane module (i=1, 2, ..., n-1). That is, the concentrate end of the first reverse osmosis membrane module 7 is connected to the third-stage high-pressure pump 8. After being pressurized by the third-stage high-pressure pump 8, it enters the second reverse osmosis membrane module 9, and so on, up to the n-th stage reverse osmosis membrane module 11. The second-stage high-pressure pump 6 provides pressure compensation for the inlet of the first reverse osmosis membrane module 7, and the (n+1)-th stage high-pressure pump 10 provides pressure compensation for the inlet of the n-th stage reverse osmosis membrane module 11. Each stage of high-pressure pump only provides pressure compensation for the concentrate flow path of the preceding stage, utilizing the residual pressure of the concentrate from the previous stage to achieve continuous operation of the system with relatively small energy input.

[0034] In this application, the reverse osmosis membrane modules in the multi-stage process are preferably loose-type membrane modules of the same model. The flux of the loose-type membrane module is higher than 2~10 L / m²·h·bar, and the boric acid removal rate is 40~90%, which can achieve efficient retention of boron ions under low pressure. The permeate end of each reverse osmosis membrane module is connected to the permeate pipeline 12. The permeate pipeline 12 is used to collect the permeate from the first reverse osmosis membrane module 7, the second reverse osmosis membrane module 9 to the nth reverse osmosis membrane module 11, and deliver it to the outside as the final permeate of the single-stage multi-stage system. The second concentrate discharge pipeline 13 provides a discharge channel for the final concentrate after the multi-stage process.

[0035] The control unit is the core of the system's intelligent regulation. It is connected to the signals of each device in the single-stage process and multi-stage process. It can determine the optimal number of operating stages n and control the operating status of the corresponding reverse osmosis membrane modules based on the feed water parameters, target product water boron concentration and target recovery rate.

[0036] Specifically, the control unit is used to acquire influent water quality parameters and product water quality targets, determine the optimal number of operating stages in the multi-stage process, and adjust the operating pressure of the first-stage high-pressure pump in the single-stage process, the operating pressure of each stage of the high-pressure pump in the multi-stage process, and the start-up and shutdown status of the reverse osmosis membrane module. The control unit is connected to the single-stage process and the multi-stage process by signal. The control unit has a built-in stage number decision algorithm and concentration prediction model, which work together to provide data support and logical basis for the decision-making and control of the control unit.

[0037] The segment number decision algorithm uses the boron concentration in the permeate as a constraint (in this application, the boron concentration in the permeate is ≤1.0 mg / L) to optimize the integer number of segments n that minimizes the energy consumption per unit of permeate or maximizes the total recovery rate. During actual operation, the control unit synchronously inputs the collected feed water quality parameters, such as boron concentration and salinity, along with manually set target boron concentration and target recovery rate, into the segment number decision algorithm. The algorithm combines the quantitative data output from the concentration prediction model to comprehensively evaluate the total system recovery rate and predicted energy efficiency under different segment numbers n, selects the optimal operating segment number n, and sends control commands to multiple processes accordingly to regulate the start and stop of the corresponding reverse osmosis membrane modules and high-pressure pumps, achieving adaptive operation of the system.

[0038] The concentration prediction model is based on the principle of mass conservation and combines the system influent flow rate, single-stage process recovery rate, multi-stage process recovery rate and membrane module removal rate to calculate the total recovery rate and total effluent concentration of the system.

[0039] The concentration prediction model operates according to the following logic: The effluent flow rate of the i-th segment in the multi-segment process is set as follows: Q Pi (i=1, 2, ..., n), then the total system flow Q P The calculation formula is: (1) Furthermore, the system inlet flow rate is set as follows: Q 0 The single-stage process recovery rate is Y 0 The recovery rate of the multi-stage process is Y The system runs in segments of 1000 segments. n Then equation (1) can be simplified to: (2) Furthermore, the overall system recovery rate Y 系统 The calculation formula is: (3) The effluent concentration of the i-th stage in the multi-stage process is set as follows: C Pi (i=1, 2, ..., n), then the total concentration of the system effluent C P for: (4) Furthermore, the system influent concentration is set to... C 0 The single-stage process membrane module has a removal rate of R 0The removal rate of the multi-stage membrane module is R Then equation (4) can be simplified to: (5) The following is a complete example illustrating the operation steps of the single-stage, multi-stage seawater desalination and boron removal system provided in this application embodiment: 1. Parameter acquisition: The control unit acquires the boron concentration, salinity, and target product water quality requirements (boron concentration ≤ 1 mg / L) of the influent water. In this application, the boron concentration of the influent water is 3~10 mg / L and the salinity is 2~4%. Alternatively, the target product water boron concentration can be set to 0.5~2.4 mg / L according to the actual operating conditions. 2. Segment number decision: The control unit uses the built-in segment number decision algorithm to comprehensively evaluate the total system recovery rate and predicted energy efficiency under different segment numbers n, and selects the optimal operating segment number n. In the embodiments of this application, the operating segment number n is 1~9, the target total system recovery rate is 0.4~0.8, and the target net specific energy consumption is 1~5 kWh / m³. 3. Single-stage process treatment: After being pressurized by the pretreatment module 1 and the first-stage high-pressure pump 2, the seawater enters the single-stage reverse osmosis membrane module 4 for the first reverse osmosis desalination and boron removal. In this application, the sodium chloride removal rate of the single-stage reverse osmosis membrane module 4 is 97.0~99.9%, and the single-stage process recovery rate is preferably 0.3~0.8. 4. Multi-stage process processing: The primary permeate produced by the single-stage process enters a multi-stage process consisting of n stages selected in step 2. The concentrate from the previous stage is pressurized by the secondary high-pressure pump 6, the tertiary high-pressure pump 8 to the n+1 stage high-pressure pump 10 and sent to the next stage membrane module. The permeates from each stage are mixed and output to the permeate pipeline 12. In this application, the recovery rate of the multi-stage process is preferably 0.3~0.8. 5. Real-time adjustment: The control unit monitors the quality of the produced water in real time through various monitoring devices, and dynamically adjusts the operating pressure of each high-pressure pump and the operating status of the reverse osmosis membrane module based on the concentration prediction model to ensure that the quality of the produced water meets the standards and that the system is in the optimal energy efficiency operating state.

[0040] The above embodiments combined Figure 1 This application introduces a single-stage multi-stage treatment system for boron removal in seawater desalination. In this system, n in the multi-stage process can be selected from 1 to 9 depending on the actual situation. However, in one implementation of this application, n in the multi-stage process is preferably 3. Figure 2 As shown, Figure 2 Another single-stage multi-stage treatment system for boron removal in seawater desalination is provided in the embodiments of this application.

[0041] Figure 2The diagram schematically illustrates the "single-stage three-section" system architecture used in the embodiments of this application. The structure includes a pretreatment module / inlet pipe 1, a first-stage high-pressure pump 2, a pressure exchanger 3, a single-stage reverse osmosis membrane module 4, a first concentrate discharge pipeline 5, a second-stage high-pressure pump 6, a first-stage reverse osmosis membrane module 7, a third-stage high-pressure pump 8, a second-stage reverse osmosis membrane module 9, a fourth-stage high-pressure pump 10, a third-stage reverse osmosis membrane module 11, a product water pipeline 12, and a second concentrate discharge pipeline 13.

[0042] The implementation process of this "single-level three-segment" system is consistent with the implementation logic of the aforementioned single-level multi-segment system, and will not be repeated here.

[0043] To further verify the practical application effect of the single-level multi-segment system architecture and optimization algorithm of this application, a detailed analysis and description are provided below in conjunction with specific embodiments.

[0044] This embodiment details a comparison of the impact of the number of stages (n) ranging from 1 to 9 on the overall system recovery rate: the recovery rate of a single-stage reverse osmosis membrane module is set to 0.5, and the recovery rate of a multi-stage reverse osmosis membrane module is set to 0.5. The overall system recovery rate is calculated using a concentration prediction model. Y 系统 Table 1 shows the impact of the number of segments n on the overall system recovery rate.

[0045]

[0046] Table 1. Impact of the number of segments n on the overall system recovery rate

[0047] The following example illustrates the system configuration optimization and validation based on the concentration prediction model: After clarifying the relationship between the number of stages and the system recovery rate, this embodiment further verifies the practical application value of the concentration prediction model in system configuration optimization and water quality prediction by combining actual seawater desalination boron removal conditions.

[0048] In this embodiment, taking a specific seawater desalination boron removal operation as an example: the influent boron concentration is set at 4 mg / L, and the product water boron concentration is controlled at 1 mg / L. The pretreatment module does not significantly affect the boron ion concentration in the solution.

[0049] The system operating parameters are set as follows: the recovery rate of the single-stage reverse osmosis membrane module is set to 0.5, and the recovery rate of each stage of the multi-stage reverse osmosis membrane module is also set to 0.5. Regarding the selection of membrane modules: the single-stage reverse osmosis membrane module uses a membrane element with a boron rejection rate of 59.2%; the multi-stage reverse osmosis membrane modules use membrane elements with a boron rejection rate of 59.2% and a water flux of 2.3 L / m³. 2 The membrane has a density of ·h·bar (denoted as component one) and a boron rejection rate of 55.0%, with a water flux of 6.6 L / m³.2 The membrane element of h bar (denoted as component two, the loose membrane).

[0050] Using the concentration prediction model described in this application, the influence of the number of stages (n) in the multi-stage process on the final boron concentration in the system effluent was quantitatively investigated. The results are shown in Table 2. Analysis of the calculation results in Table 2 indicates that when the multi-stage process uses cascaded components one and two, the maximum number of stages (n) that the system can support is 3 (i.e., a single-stage three-stage system, such as...) under the premise of meeting the permeate standards. Figure 2 (As shown).

[0051] Calculation results confirm that when the number of stages n>3, due to the concentration effect, the boron concentration in the effluent will exceed the limit of 1 mg / L, failing to meet the requirements for product water quality.

[0052] This embodiment further demonstrates the specific application logic of the concentration prediction algorithm of this application in determining the optimal number of operating stages for the system and predicting water quality stability. For those skilled in the art, based on the calculation logic disclosed in this application, system configuration optimization and parameter adjustment for reverse osmosis membrane modules with different rejection characteristics or permeability performance all fall within the protection scope of this application.

[0053]

[0054] Table 2 Relationship between membrane modules used in multi-stage processes and system effluent concentration

[0055] After determining the optimal range of number of segments to meet water quality requirements, this embodiment further explores the impact of the number of segments on the net specific energy consumption of the system, thereby achieving the dual goals of water quality compliance and optimal energy efficiency, and completing the comprehensive verification of the proposed solution.

[0056] This embodiment aims to investigate the impact of the number of stages n in a multi-stage process on the system's net specific energy consumption (NSEC). During the experiment, the same system optimization parameter settings as in the above embodiment were used, including the recovery rate of each stage and the selection of membrane modules. The system energy consumption performance under different numbers of stages was calculated, and the specific results are detailed in Table 3.

[0057] Based on the results in Table 1, increasing the number of stages (n) in the multi-stage process helps improve the overall recovery rate of the system, thereby macroscopically reducing the specific energy consumption per unit of produced water. However, as shown in Table 2, an excessively high recovery rate can lead to nonlinear deterioration of the produced water quality. Therefore, the algorithm described in this application is used to comprehensively evaluate the water quality-energy consumption trade-off, compared to the traditional "two-stage reverse osmosis" process (2.40 kWh / m³). 3 The specific energy consumption of a single-stage multi-stage process system operating under the optimal parameter window (n=3) can be reduced to 1.60 kWh / m³. 3 The energy consumption reduction rate was 33.3%.

[0058] Furthermore, if the high-flux porous membrane described in this application is integrated into multiple processes, its technical advantages of low pressure and high permeability can be fully utilized, further reducing the system's specific energy consumption to 1.38 kWh / m³. 3 The energy consumption reduction rate is 42.5%. Those skilled in the art should understand that any technical solution that utilizes a high-flux porous membrane and combines it with the system cascade optimization method disclosed in this application for system energy optimization falls within the scope of protection of the claims of this patent.

[0059]

[0060] Table 3 System energy consumption performance at different levels

[0061] This application has the following beneficial effects: This application provides a high-recovery seawater desalination boron removal system and method with an adaptive cascade configuration, achieving deep decoupling of energy demand and boron removal performance through a system paradigm shift. Unlike traditional processes that directly discharge or simply recirculate the concentrate, this application designs a multi-stage process for gradient reuse of the concentrate. High-pressure pumps between stages are used to progressively pressurize the concentrate generated in the preceding stages, thereby significantly improving the overall system recovery rate while ensuring boron removal efficiency. The system abandons the rigid design of a fixed number of physical stages. Through a decision algorithm based on the mass balance equation, it comprehensively evaluates intrinsic performance parameters such as the rejection rate and water permeability coefficient of the current membrane material, calculates and determines the minimum number of operating stages n required to meet the target product water standard, achieving precise "on-demand rejection" and effectively avoiding energy waste caused by over-treatment. Furthermore, the multi-stage pressurization mechanism introduced in this application provides precise pressure compensation only for necessary flow paths, avoiding ineffective high-pressure transport of the entire product water volume. Combined with a pressure exchanger to maximize the recovery of concentrated water pressure energy, and integrated with the optimal operating parameter range determined by a concentration prediction model, the system can utilize high-flux, porous membrane materials to achieve optimal energy efficiency while strictly controlling the boron concentration in the product water below 1 mg / L. This adaptive mechanism, which uses a concentration prediction model to calculate the contribution ratio of each stage of product water to the final mixed product water in real time, enables the process to dynamically respond to complex and changing operating conditions and different regional influent standards. This provides a highly versatile and intelligent solution for the efficient removal of seawater desalination and neutral small molecule pollutants.

[0062] This application also provides a single-stage multi-stage treatment method for boron removal in seawater desalination, which is applied to the single-stage multi-stage treatment system for boron removal in seawater desalination provided in this application. Figure 3 A flowchart of a single-stage, multi-stage treatment method for boron removal in seawater desalination, provided in an embodiment of this application, is shown below. Figure 3 As shown, the method includes: S301. Obtain seawater influent quality parameters and product water quality targets; S302. Determine the optimal number of operating segments n for a multi-segment process through the control unit; S303. After the seawater is pretreated by the pretreatment module of the single-stage process, it is then desalinated and debored by the first stage of the single-stage process to output the first-stage product water. The first-stage product water is then sent to the multi-stage process corresponding to the optimal operating stage for gradient reverse osmosis deboring. S304. Real-time monitoring of the product water quality of multiple processes and dynamic adjustment of the operating status of single-stage and multi-stage processes; S305. Collect the permeate from multiple stages of the process to complete the desalination and boron removal of seawater.

[0063] In one implementation of this application, determining the optimal number of running segments n of the multi-segment process through the control unit includes: By using the segment number decision algorithm built into the control unit, and taking the boron concentration in the produced water reaching a preset standard as a constraint, the optimal number of operating segments n for the multi-stage process is obtained, which minimizes the energy consumption per unit of produced water or maximizes the total recovery rate. Here, n is an integer greater than or equal to 2.

[0064] In one implementation of this application, the real-time monitoring of the product water quality of multiple processes and the dynamic adjustment of the operating status of the single-stage process and the multiple-stage process include: The total recovery rate and total effluent concentration of the system are calculated by the concentration prediction model built into the control unit. Combined with the product water quality monitoring data, the operating pressure of the first-stage high-pressure pump in the single-stage process, the operating pressure of each stage of the high-pressure pump in the multi-stage process, and the start-up and shutdown status of the reverse osmosis membrane module are adjusted.

[0065] In one implementation of this application, the step of sending the primary permeate into a multi-stage process corresponding to the optimal operating stage for gradient reverse osmosis boron removal includes: After the primary permeate is sent into the multi-stage process, the concentrate produced by the i-th stage reverse osmosis membrane module is pressurized by the (i+2)-th stage high-pressure pump and then sent into the (i+1)-th stage reverse osmosis membrane module for boron removal, where i = 1, 2, ..., n-1.

[0066] In one implementation of this application, during the initial reverse osmosis desalination and boron removal process of the single-stage reverse osmosis membrane module after pressurization by a first-stage high-pressure pump, the energy of the high-pressure concentrate discharged from the single-stage reverse osmosis membrane module is recovered through a pressure exchanger. The pressure energy of the high-pressure concentrate is then transferred to the low-pressure feed water entering the pressure exchanger, thereby pressurizing the low-pressure feed water before it is sent to the first-stage high-pressure pump.

[0067] In one implementation of this application, during the gradient reverse osmosis boron removal process, the permeate from each section of the reverse osmosis membrane module is collected into the permeate pipeline through its permeate end, and the permeate from multiple stages is collected and transported outward by the permeate pipeline.

[0068] It should be noted that the implementation process, operating principle and related process parameters of this method can be referred to the corresponding description in the aforementioned embodiment of the single-stage multi-stage treatment system for boron removal in seawater desalination in this application, and the relevant details will not be repeated here.

[0069] This application also provides corresponding devices and computer storage media for implementing the solutions provided in this application.

[0070] The device includes a memory and a processor. The memory stores instructions or code, and the processor executes the instructions or code to cause the device to perform the method described in any embodiment of this application.

[0071] The computer storage medium stores code, and when the code is run, the device running the code implements the method described in any embodiment of this application.

[0072] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0073] It is understood that in the specific embodiments of this application, the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved need to obtain user permission or consent when the above embodiments of this application are applied to specific products or technologies, and the collection, use and processing of related data need to comply with the relevant laws, regulations and standards of relevant countries and regions.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0075] It should also be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device and apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device and apparatus embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0076] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A single-stage, multi-stage treatment system for boron removal in seawater desalination, characterized in that, The system includes a single-stage process and a multi-stage process connected in sequence, a control unit connected to the single-stage process and the multi-stage process, and a product water pipeline connected to the multi-stage process; The single-stage process includes a pretreatment module, a first-stage high-pressure pump, a pressure exchanger, a single-stage reverse osmosis membrane module, and a first concentrate discharge pipeline. The single-stage process pre-treats the seawater raw water through a pretreatment module, performs the first reverse osmosis desalination and boron removal on the pre-treated seawater through a first-stage high-pressure pump and a single-stage reverse osmosis membrane module, recovers the high-pressure concentrate energy through a pressure exchanger, completes the low-pressure feed water pressurization, and outputs the first-stage product water to the multi-stage process. The multi-stage process includes a secondary high-pressure pump, a tertiary high-pressure pump, and up to an n+1th high-pressure pump, n reverse osmosis membrane modules connected in series, and a second concentrate discharge pipeline, where n is an integer greater than or equal to 2; the multi-stage process is used to receive the first-stage permeate output from the single-stage process, and to stepwise pressurize the concentrate from the preceding stage through each stage of high-pressure pumps, and then send the pressurized concentrate to the next stage of reverse osmosis membrane module for reverse osmosis boron removal; The control unit is used to acquire influent water quality parameters and product water quality targets, determine the optimal number of operating segments in the multi-stage process, and adjust the operating pressure of the first-stage high-pressure pump in the single-stage process, the operating pressure of each stage of the high-pressure pump in the multi-stage process, and the start-up and shutdown status of the reverse osmosis membrane module. The product water pipeline is used to collect the product water output from the multi-stage process and transport it externally.

2. The system according to claim 1, characterized in that, The control unit is connected to the single-stage process and the multi-stage process by a signal, and the control unit has a built-in stage number decision algorithm and concentration prediction model.

3. The system according to claim 2, characterized in that, The segment number decision algorithm uses the boron concentration in the produced water reaching a preset standard as a constraint to find the optimal number of operating segments n for the multi-segment process that minimizes the energy consumption per unit of produced water or maximizes the total recovery rate.

4. The system according to claim 2, characterized in that, The concentration prediction model is based on the principle of mass conservation and combines the system influent flow rate, single-stage process recovery rate, multi-stage process recovery rate and membrane module removal rate to calculate the total recovery rate and total effluent concentration of the system.

5. The system according to claim 1, characterized in that, The pressure exchanger is connected to the low-pressure inlet of the first-stage high-pressure pump and the concentrate outlet of the single-stage reverse osmosis membrane module, respectively. The pressure exchanger is used to receive the high-pressure concentrate discharged from the single-stage reverse osmosis membrane module and transfer the pressure energy of the high-pressure concentrate to the low-pressure inlet entering the pressure exchanger.

6. The system according to claim 1, characterized in that, In the n-segment reverse osmosis membrane modules connected in series, the concentrate end of the i-th segment reverse osmosis membrane module is connected to the inlet end of the (i+2)-th stage high-pressure pump, and after pressure compensation by the (i+2)-th stage high-pressure pump, it is connected to the inlet end of the (i+1)-th segment reverse osmosis membrane module, where i = 1, 2, ..., n-1; the product water end of each segment reverse osmosis membrane module is connected to the product water pipeline.

7. A single-stage, multi-stage treatment method for boron removal in seawater desalination, characterized in that, The method, applied to the single-stage multi-stage treatment system for boron removal in seawater desalination according to any one of claims 1-6, comprises: Obtain seawater influent quality parameters and product water quality targets; The optimal number of running segments n for a multi-segment process is determined by the control unit; After the raw seawater is pretreated by a single-stage pretreatment module, it is then desalinated and debored by reverse osmosis for the first time in a single-stage process to output primary product water. The primary product water is then sent to a multi-stage process with the corresponding optimal operating stage for gradient reverse osmosis deboring. Real-time monitoring of the product water quality of multiple processes and dynamic adjustment of the operation status of single-stage and multi-stage processes; The permeate from multiple stages of the process is collected to complete the desalination and boron removal of seawater.

8. The method according to claim 7, characterized in that, The determination of the optimal number of operating segments n for a multi-segment process via the control unit includes: By using the segment number decision algorithm built into the control unit, and taking the boron concentration in the produced water reaching a preset standard as a constraint, the optimal number of operating segments n for the multi-stage process is obtained, which minimizes the energy consumption per unit of produced water or maximizes the total recovery rate. Here, n is an integer greater than or equal to 2.

9. The method according to claim 7, characterized in that, The real-time monitoring of the product water quality of multiple processes and the dynamic adjustment of the operating status of single-stage and multi-stage processes include: The total recovery rate and total effluent concentration of the system are calculated by the concentration prediction model built into the control unit. Combined with the product water quality monitoring data, the operating pressure of the first-stage high-pressure pump in the single-stage process, the operating pressure of each stage of the high-pressure pump in the multi-stage process, and the start-up and shutdown status of the reverse osmosis membrane module are adjusted.

10. The method according to claim 7, characterized in that, The step of sending primary permeate into a multi-stage process corresponding to the optimal operating stage for gradient reverse osmosis boron removal includes: After the primary permeate is sent into the multi-stage process, the concentrate produced by the i-th stage reverse osmosis membrane module is pressurized by the (i+2)-th stage high-pressure pump and then sent into the (i+1)-th stage reverse osmosis membrane module for boron removal, where i = 1, 2, ..., n-1.

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