Reverse osmosis membrane assembly and seawater desalination system

Abstract

The invention discloses a reverse osmosis membrane assembly which comprises a reverse osmosis core and sealing covers mounted at two ends of the reverse osmosis core in a sealing manner, the reverse osmosis core comprises a middle inner membrane supporting layer as well as two groups of micro-filtration membranes and two groups of ultra-filtration membranes which wrap the outer side of the inner membrane supporting layer, a laminated pre-filtration layer is arranged between the micro-filtration membranes and the ultra-filtration membranes wrapping the inner membrane supporting layer, a PA reverse osmosis membrane wraps the rear parts of the micro-filtration membranes and the ultra-filtration membranes, and a separation net is arranged behind the PA reverse osmosis membrane; due to the synergistic effect of the multiple layers of membranes, the system can treat a more complex and worse seawater environment, and the stability and reliability of the effluent quality are ensured; due to the design of the laminated pre-filtering layer and the separation net, pollutants are effectively prevented from being in direct contact with the membrane holes and blocking the membrane holes, and the stability of the membrane assembly is further enhanced. Due to the introduction of the automatic backwashing device, the automatic backwashing device can be automatically started at regular intervals or according to a water quality monitoring result, the pre-filter is subjected to backwashing, the service life of the pre-filter is prolonged, and the maintenance cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of reverse osmosis membrane components, in particular to a reverse osmosis membrane component and a seawater desalination system of the reverse osmosis membrane component. Background Art

[0002] As the global water shortage problem becomes increasingly serious, seawater desalination technology, as one of the important means to solve the water crisis, has received extensive attention and research. Traditional seawater desalination methods include distillation and electrodialysis, but these methods often have problems such as high energy consumption, complex equipment, and high maintenance costs. Therefore, the development of efficient, energy-saving, and environmentally friendly seawater desalination technology has become a hot topic in current research.

[0003] In the process of seawater desalination, reverse osmosis technology is widely used due to its advantages such as high efficiency, energy saving and easy operation. However, when treating seawater, traditional reverse osmosis membrane components often face problems such as membrane fouling, flux decline and retention performance decline, which seriously affects the efficiency of seawater desalination and effluent quality. Therefore, improving the anti-pollution, stability and retention performance of reverse osmosis membrane components has become the key to improving the level of seawater desalination technology.

[0004] Existing reverse osmosis membrane components usually include single or multi-layer membrane structures, but these membrane structures are insufficient in removing suspended particles, bacteria, large organic matter, small organic molecules, oils, heavy metal ions, etc. in seawater. At the same time, traditional reverse osmosis membrane materials often have unstable membrane performance and are easy to be contaminated during the preparation process. Summary of the invention

[0005] The technical problem solved by the present invention is to overcome the defects mentioned in the background technology and provide a reverse osmosis membrane assembly and a seawater desalination system using the reverse osmosis membrane assembly.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a reverse osmosis membrane assembly, comprising a reverse osmosis core and sealing covers sealed at both ends of the reverse osmosis core; the reverse osmosis core comprises an inner membrane support layer in the middle and two groups of microfiltration membranes and two groups of ultrafiltration membranes wrapped on the outside of the inner membrane support layer, a laminated pre-filtration layer is arranged between the inner membrane support layer wrapped by the microfiltration membrane and the ultrafiltration membrane, a PA reverse osmosis membrane is wrapped behind the microfiltration membrane and the ultrafiltration membrane, a partition net is arranged behind the PA reverse osmosis membrane, and an activated carbon layer is arranged on the outside of the partition net, and the activated carbon layer is composed of an activated carbon inner protective layer, an activated carbon outer protective layer and two groups of activated carbon filled inside.

[0007] Furthermore, the preparation method of the PA reverse osmosis membrane is as follows: using interfacial polymerization combined with IP-UV graft polymerization coupling technology, using m-phenylenediamine and trimesoyl chloride as reaction monomers, adding highly soluble ionic liquid 1-allyl-3-methylimidazolium chloride as an additive in the aqueous phase, inhibiting MPD diffusion, promoting the formation of the primary polyamide layer, UV-induced graft polymerization and heat treatment reconstruction; introducing a new additive Tween 80 in the organic phase, and generating a TW-TMC product by reacting Tween 80 with TMC.

[0008] Furthermore, the microfiltration membrane uses a polyvinylidene fluoride hollow fiber membrane with a molecular weight cutoff of 500ku and 300ku, respectively, while the ultrafiltration membrane uses a polyethersulfone hollow fiber membrane with a molecular weight cutoff of 100ku and 50ku, respectively, and the molecular weight cutoff of the laminated pre-filtration layer is 50μm.

[0009] Furthermore, in the IP-UV graft polymerization coupling film-making method, the UV-initiated graft polymerization step uses an ultraviolet light source with a wavelength of 254 nm and is carried out under nitrogen protection, and the heat treatment reconstruction step is carried out in a temperature range of 120°C to 150°C and lasts for 30 minutes to 60 minutes.

[0010] Furthermore, the separator is woven from a stainless steel wire mesh with a mesh number of 100 to 200 meshes, and the inner membrane support layer is made of a high-strength, corrosion-resistant polypropylene material, and its surface is microporous.

[0011] Furthermore, the laminated pre-filter layer is formed by laminating multiple layers of polypropylene fiber non-woven fabrics, and a supporting frame is provided between each layer.

[0012] A seawater desalination system, the seawater desalination system comprises the following steps: Step 1: Pretreatment unit: used for preliminary treatment of seawater to remove suspended particles, bacteria and large organic matter in the seawater, the pretreatment unit comprises: Pre-filter: It is installed at the seawater inlet and is used to initially filter large particles of impurities in the seawater to reduce the load of subsequent membrane components; Membrane filtration components: Microfiltration membrane components are used to further remove tiny particles, colloids and some bacteria in seawater, while ultrafiltration membrane components are used to intercept smaller bacteria and suspended solids with larger molecular weight. Both microfiltration membrane components and ultrafiltration membrane components adopt hollow fiber membrane structure; Adsorption filter: installed after the membrane filtration component, used to adsorb small molecular organic matter, oil, and heavy metal ions in seawater to further improve the effluent quality; Step 2: Reverse osmosis membrane assembly: connected to the pretreatment unit, used to separate the fresh water and salt in the pretreated seawater through the osmotic pressure principle to obtain desalinated water; Step 3: Control system: used to monitor and adjust the operating status of the entire system, including but not limited to monitoring the transmembrane pressure difference of each membrane component, effluent water quality parameters such as turbidity and UV254, and automatically executing the cleaning procedure according to the preset maintenance conditions. When the transmembrane pressure difference reaches or exceeds the preset threshold, the maintenance cleaning is started to restore the transmembrane pressure difference to a low pressure level to ensure the long-term stable operation of the system; Step 4: Cleaning unit: connected to the reverse osmosis membrane assembly, used for maintenance cleaning under the instruction of the control system to remove pollutants attached to the surface of the membrane assembly and restore the flux and retention performance of the membrane assembly.

[0013] Furthermore, the pretreatment unit also includes an automatic backwashing device, which can be automatically started periodically or according to water quality monitoring results to backwash the prefilter to remove impurities accumulated on the filter, thereby extending the service life of the prefilter and reducing maintenance costs.

[0014] Furthermore, the cleaning unit adopts a combination of ultrasonic cleaning and chemical cleaning, wherein ultrasonic cleaning is used to preliminarily remove loose dirt on the surface of the membrane component, while chemical cleaning is used to deeply clean stubborn contaminants in the membrane pores to ensure thorough cleaning of the membrane component and restore its performance.

[0015] Compared with the prior art, the present invention has the following beneficial effects: Significantly improve seawater desalination efficiency and effluent quality: The reverse osmosis membrane assembly of the present invention adopts a multi-layer composite membrane structure, including a microfiltration membrane, an ultrafiltration membrane and a PA reverse osmosis membrane, as well as a laminated pre-filtration layer and an activated carbon layer. These designs are progressive, effectively removing suspended particles, bacteria, large organic matter, small organic molecules, grease and heavy metal ions in seawater, and significantly improving the efficiency of seawater desalination and the quality of effluent water. The synergistic effect of the multi-layer membrane enables the system to handle more complex and harsher seawater environments, ensuring the stability and reliability of the effluent water quality.

[0016] Enhance the anti-fouling and stability of membrane components: The PA reverse osmosis membrane prepared by interfacial polymerization combined with IP-UV graft polymerization coupling technology not only improves the membrane's retention performance and flux, but also significantly enhances the membrane's anti-pollution ability. The introduction of highly soluble ionic liquids and new additives optimizes the structure and performance of the membrane, making it less likely to be contaminated during long-term use and extending the membrane's service life. At the same time, the design of the laminated pre-filtration layer and the spacer also effectively prevents pollutants from directly contacting and clogging the membrane pores, further enhancing the stability of the membrane assembly.

[0017] Optimize pretreatment and cleaning units to reduce maintenance costs: The seawater desalination system of the present invention is designed with an efficient pretreatment unit and a cleaning unit. The pretreatment unit effectively removes most of the impurities in the seawater through layer-by-layer treatment of the prefilter, the membrane filtration assembly and the adsorption filter, thereby reducing the load of the subsequent membrane assembly. At the same time, the introduction of the automatic backwashing device can be automatically started regularly or according to the water quality monitoring results to backwash the prefilter, thereby extending the service life of the prefilter and reducing maintenance costs. The cleaning unit adopts a combination of ultrasonic cleaning and chemical cleaning, which can completely remove pollutants on the surface of the membrane assembly, restore the flux and interception performance of the membrane assembly, and reduce the system downtime and maintenance costs caused by membrane pollution.

[0018] Enhance system reliability and durability: The reverse osmosis membrane assembly and the seawater desalination system of the present invention are made of high-strength and corrosion-resistant materials, such as an inner membrane support layer made of polypropylene material and a spacer woven of stainless steel wire mesh. These materials have good physical and chemical properties and can operate stably for a long time in a harsh seawater environment without being damaged. At the same time, the multi-layer composite membrane structure and the optimized cleaning unit design also enhance the reliability and durability of the system, so that the system can maintain an efficient and stable operating state for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the reverse osmosis membrane assembly of the present invention; Figure 2 It is a schematic diagram of the seawater desalination system of the present invention.

[0020] Numbers in the figure: 1. Cap; 2. Reverse osmosis core; 3. Inner membrane support layer; 4. Laminated pre-filtration layer; 5. Microfiltration membrane; 6. Ultrafiltration membrane; 7. PA reverse osmosis membrane; 8. Spacer; 9. Activated carbon inner protective layer; 10. Activated carbon outer protective layer. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0022] See also Figure 1 The present invention provides a technical solution: a reverse osmosis membrane assembly, a reverse osmosis membrane assembly manufacturing method Step 1: Prepare Materials Inner membrane support layer 3: High-strength, corrosion-resistant polypropylene material is selected and microporous treatment is performed to increase its surface area and filtering effect.

[0023] Microfiltration membrane 5: Using polyvinylidene fluoride hollow fiber membrane, two membranes with different molecular weight cutoffs were prepared, namely 500ku and 300ku.

[0024] Ultrafiltration membrane 6: Polyethersulfone hollow fiber membrane was selected, and two membranes with different molecular weight cutoffs were also prepared, namely 100ku and 50ku.

[0025] Laminated pre-filter layer 4: It is made of multiple layers of polypropylene fiber non-woven fabrics, and a supporting skeleton is arranged between each layer to ensure the stability and filtering effect of the filter layer. Its molecular weight cutoff is 50μm.

[0026] PA reverse osmosis membrane 7: The raw materials are m-phenylenediamine and trimesoyl chloride, as well as additives 1-allyl-3-methylimidazolium chloride and Tween 80.

[0027] The separator 8 is woven from a stainless steel wire mesh with a mesh number of 100 to 200.

[0028] Activated carbon layer: It is composed of an activated carbon inner protective layer 9, an activated carbon outer protective layer 10 and two groups of internally filled activated carbon.

[0029] Step 2: Assemble the reverse osmosis core 2 The processed inner membrane supporting layer 3 is placed on the assembly table.

[0030] The laminated pre-filtration layer 4 is firstly wrapped on the outer side of the inner membrane support layer 3 to ensure that the support frame is positioned correctly between the non-woven fabric layers, so as to increase the filtration area and the filtration effect.

[0031] Next, two groups of microfiltration membranes 5 and two groups of ultrafiltration membranes 6 are sequentially wrapped around the outside of the laminated pre-filtration layer 4 to ensure that each layer of the membrane fits tightly without bubbles or wrinkles.

[0032] The PA reverse osmosis membrane 7 is wrapped around the outer layer of the ultrafiltration membrane 6. In this step, special attention should be paid to the flatness and sealing of the membrane.

[0033] A spacer 8 is installed behind the PA reverse osmosis membrane 7 to support and protect the subsequent activated carbon layer.

[0034] Finally, an activated carbon layer is arranged outside the separator 8, which is composed of an activated carbon inner protective layer 9, an activated carbon outer protective layer 10 and two groups of internally filled activated carbons, to ensure that the activated carbon layer can effectively absorb organic matter and impurities in the water.

[0035] Step 3: Install cover 1 Sealed covers 1 are respectively installed on both ends of the assembled reverse osmosis core 2 to ensure the sealing and integrity of the entire reverse osmosis membrane assembly.

[0036] Step 4: Overall test: Conduct comprehensive performance tests on the assembled reverse osmosis membrane components, including but not limited to pressure test, permeation flux test, desalination rate test and anti-pollution test; make necessary adjustments and optimizations to the components based on the test results to ensure that all performance indicators meet the design requirements.

[0037] Production of PA reverse osmosis membrane 7: Step 1: Interfacial Polymerization Preparation Prepare reaction monomers m-phenylenediamine and trimesoyl chloride, and additive 1-allyl-3-methylimidazolium chloride.

[0038] Highly soluble ionic liquid 1-allyl-3-methylimidazolium chloride is added to the aqueous phase, and the solution concentration and pH value are adjusted to a suitable range.

[0039] Step 2: IP-UV graft polymerization coupling Prepare the aqueous phase and organic phase containing TMC and Tween 80 separately to ensure stable reaction conditions.

[0040] In the water phase, the formation of the primary polyamide layer is promoted by controlling the diffusion rate of MPD.

[0041] The UV-initiated graft polymerization step was carried out under nitrogen protection using an ultraviolet light source with a wavelength of 254 nm to ensure uniformity and high efficiency of the grafting reaction.

[0042] The membrane after the reaction is reconstructed by heat treatment, and is continuously heated in a temperature range of 120°C to 150°C for 30 minutes to 60 minutes to optimize the structure and performance of the membrane.

[0043] In the organic phase, Tween 80 reacts with TMC to generate TW-TMC product, which helps to further improve the hydrophilicity and anti-fouling properties of the membrane.

[0044] Step 3: Post-treatment and testing of membrane The manufactured PA reverse osmosis membrane 7 is cleaned, dried and performance tested to ensure that it meets the design requirements, and then assembled according to the above steps. Example

[0045] The present invention provides a technical solution: a reverse osmosis membrane assembly, and the manufacture of the reverse osmosis membrane assembly: 1. Material preparation Membrane material: High-performance polyamide (PA) material is selected as the main component of the reverse osmosis membrane. This material has excellent desalination performance, high flux and good anti-pollution properties.

[0046] Support layer: Polyester nonwoven fabric is used as the support layer, which has a smooth surface and no scattered fibers, which helps to form a stable membrane structure.

[0047] Intermediate carrier layer: A porous polysulfone (PSF) material is selected as the intermediate carrier layer, and its diameter is about 150 angstroms (ie 15 nanometers), which can provide good support and filtering effects.

[0048] Separation layer: Aromatic acrylic resin with a high degree of cross-linking is used as the separation layer material. Its thickness is about 0.2 microns. It has high chemical stability and durability and is the key layer for achieving efficient desalination.

[0049] Other auxiliary materials: including adhesives, sealing tapes, etc., used for the assembly and sealing of membrane elements.

[0050] 2. Preparation Process Membrane material preparation: The polyamide material is pre-treated, such as dissolving, filtering, etc., to ensure its purity and uniformity.

[0051] The treated polyamide material is deposited on the support layer to form a film by using a dipping method, a phase transfer method or a biaxial stretching method.

[0052] Through chemical modification and physical membrane structure adjustment, the membrane pore size and performance can be controlled to meet different filtration requirements.

[0053] Preparation of intermediate carrier layer and separation layer: The polysulfone material is processed into a porous structure and fixed on the supporting layer to form an intermediate carrier layer.

[0054] A highly cross-linked aromatic acrylic resin is coated on the intermediate carrier layer to form an ultra-thin separation layer.

[0055] Membrane element assembly: The prepared membrane sheets are stacked in a certain layering order to ensure that the layers fit tightly and without bubbles.

[0056] Adhesives are used to bond the membrane layers together to form a complete membrane element structure.

[0057] Use sealing tape to seal the ends and sides of the membrane element to ensure the sealing and integrity of the membrane element.

[0058] Curing and post-processing: The assembled membrane elements are placed in a constant temperature and humidity space for curing to improve the stability and durability of the membrane elements.

[0059] The cured membrane elements are subjected to necessary post-processing operations, such as cleaning and testing, to ensure that they meet the quality requirements.

[0060] Quality inspection and packaging: Use automatic reverse osmosis membrane element testing equipment to conduct 100% testing on membrane elements, including flow testing, salinity testing, pH testing, pollutant testing, etc., to ensure that the membrane elements meet high quality requirements.

[0061] The membrane elements that have passed the inspection are transported to the packaging workshop for aseptic packaging to prevent contamination during transportation and storage. Example

[0062] See also Figure 2 The present invention provides a technical solution: an efficient seawater desalination system, which includes a pretreatment unit, a reverse osmosis membrane assembly, a control system and a cleaning unit.

[0063] Preprocessing unit: Pre-filter: A stainless steel filter with a pore size of 50μm is used as a pre-filter and installed at the seawater inlet to initially filter out large particles of impurities in the seawater, such as seaweed and shell fragments.

[0064] Membrane filtration components: Microfiltration membrane assembly: uses polyvinylidene fluoride hollow fiber membrane to further remove tiny particles, colloids and some bacteria in seawater.

[0065] Ultrafiltration membrane assembly: Polyethersulfone hollow fiber membrane is used to intercept smaller bacteria and suspended solids with larger relative molecular mass.

[0066] Adsorption filter: Built-in activated carbon particles are used to adsorb small molecular organic matter, oil, heavy metal ions, etc. in seawater to improve the water quality.

[0067] Automatic backwashing device: installed after the pre-filter, equipped with a water quality monitoring sensor. When it detects that the water quality has deteriorated or the preset time has arrived, it automatically starts the backwashing program to remove impurities on the pre-filter.

[0068] Reverse osmosis membrane components: The reverse osmosis membrane assembly of the first embodiment has high desalination rate, high flux and good anti-pollution performance.

[0069] The membrane components are designed to be modular for easy replacement and maintenance.

[0070] Control system: Equipped with PLC programmable logic controller and touch screen interface, real-time monitoring of transmembrane pressure difference of each membrane component, effluent water quality parameters: turbidity, UV254.

[0071] The transmembrane pressure difference threshold is preset, and when it is reached or exceeded, the cleaning procedure is automatically started.

[0072] Cleaning unit: Ultrasonic cleaning equipment: Use ultrasonic vibration to initially remove loose dirt on the surface of the membrane assembly.

[0073] Chemical cleaning system: includes cleaning liquid storage tank, circulation pump and heating device, which are used to configure and circulate chemical cleaning liquid to deeply clean the stubborn pollutants in the membrane pores.

[0074] Pretreatment effect analysis: The water quality monitoring sensors were used to record the turbidity, suspended matter content and other parameters of the seawater before and after pretreatment, and the removal efficiency of the pre-filter and membrane filtration components was analyzed.

[0075] Regularly check the pre-filter for blockage and evaluate the effectiveness of the automatic backwash device.

[0076] Reverse osmosis membrane module performance monitoring: Monitor the transmembrane pressure difference in real time, record and analyze its changing trend to evaluate the contamination degree and cleaning requirements of the membrane components.

[0077] Regularly test the effluent water quality parameters: turbidity, UV254, conductivity, to ensure that the effluent water quality meets the design requirements.

[0078] Cleaning effect evaluation: After each cleaning, the transmembrane pressure difference and effluent quality before and after cleaning were compared to evaluate the cleaning effect.

[0079] Analyze the synergistic effect of ultrasonic cleaning and chemical cleaning, and optimize the cleaning procedure and cleaning fluid formula.

[0080] System maintenance and optimization: According to the data analysis results, the cleaning cycle and cleaning intensity of the pretreatment unit are adjusted.

[0081] Optimize the cleaning strategy of reverse osmosis membrane components, reduce unnecessary cleaning times, and extend the service life of membrane components.

[0082] Regularly conduct comprehensive inspection and maintenance of the system to ensure long-term stable operation of the system.

Claims

1. A reverse osmosis membrane assembly, characterized in that: The invention comprises a reverse osmosis core (2) and a cover (1) sealed and installed at both ends of the reverse osmosis core (2); the reverse osmosis core (2) comprises an inner membrane support layer (3) in the middle and two groups of microfiltration membranes (5) and two groups of ultrafiltration membranes (6) wrapped outside the inner membrane support layer (3); a laminated pre-filtration layer (4) is arranged between the inner membrane support layer (3) wrapped by the microfiltration membrane (5) and the ultrafiltration membrane (6); a PA reverse osmosis membrane (7) is wrapped behind the microfiltration membrane (5) and the ultrafiltration membrane (6); a spacer (8) is arranged behind the PA reverse osmosis membrane (7); and an activated carbon layer is arranged outside the spacer (8); and the activated carbon layer is composed of an activated carbon inner protective layer (9), an activated carbon outer protective layer (10) and two groups of activated carbon filled inside.

2. A reverse osmosis membrane assembly according to claim 1, characterized in that: The preparation method of the PA reverse osmosis membrane (7) is as follows: using interfacial polymerization combined with IP-UV graft polymerization coupling technology, using m-phenylenediamine and trimesoyl chloride as reaction monomers, adding highly soluble ionic liquid 1-allyl-3-methylimidazole chloride as an additive in the aqueous phase, inhibiting MPD diffusion, promoting the formation of the primary polyamide layer, UV-induced graft polymerization and heat treatment reconstruction; introducing a new additive Tween 80 in the organic phase, and generating a TW-TMC product through the reaction of Tween 80 and TMC.

3. A reverse osmosis membrane assembly according to claim 2, characterized in that: The microfiltration membrane (5) uses a polyvinylidene fluoride hollow fiber membrane with molecular weight cutoffs of 500 ku and 300 ku, respectively, while the ultrafiltration membrane (6) uses a polyethersulfone hollow fiber membrane with molecular weight cutoffs of 100 ku and 50 ku, respectively. Meanwhile, the molecular weight cutoff of the laminated pre-filtration layer (4) is 50 μm.

4. A reverse osmosis membrane assembly according to claim 3, characterized in that: In the IP-UV graft polymerization coupling film-making method, the UV-initiated graft polymerization step uses an ultraviolet light source with a wavelength of 254nm and is carried out under nitrogen protection, and the heat treatment reconstruction step is carried out at a temperature range of 120°C to 150°C and lasts for 30 minutes to 60 minutes.

5. A reverse osmosis membrane assembly according to claim 4, characterized in that: The separator (8) is woven from a stainless steel wire mesh with a mesh size of 100 to 200 meshes. The inner membrane support layer (3) is made of a high-strength, corrosion-resistant polypropylene material, and its surface is subjected to a microporous treatment.

6. A reverse osmosis membrane assembly according to claim 5, characterized in that: The laminated pre-filter layer (4) is formed by laminating multiple layers of polypropylene fiber non-woven fabric, with a supporting skeleton being arranged between each layer.

7. A seawater desalination system using a reverse osmosis membrane assembly according to any one of claims 1 to 6, characterized in that: The desalination system comprises the following steps: Step 1: Pretreatment unit: used to preliminarily treat the seawater to remove suspended particles, bacteria and large organic matter in the seawater. The pretreatment unit comprises: Pre-filter: It is installed at the seawater inlet and is used to initially filter large particles of impurities in the seawater to reduce the load of subsequent membrane components; Membrane filtration components: Microfiltration membrane components are used to further remove tiny particles, colloids and some bacteria in seawater, while ultrafiltration membrane components are used to intercept smaller bacteria and suspended solids with larger molecular weight. Both microfiltration membrane components and ultrafiltration membrane components adopt hollow fiber membrane structure; Adsorption filter: installed after the membrane filtration component, used to adsorb small molecular organic matter, oil, and heavy metal ions in seawater to further improve the effluent quality; Step 2: Reverse osmosis membrane assembly: connected to the pretreatment unit, used to separate the fresh water and salt in the pretreated seawater through the osmotic pressure principle to obtain desalinated water; Step 3: Control system: used to monitor and adjust the operating status of the entire system, including but not limited to monitoring the transmembrane pressure difference of each membrane component, effluent water quality parameters such as turbidity and UV254, and automatically executing the cleaning procedure according to the preset maintenance conditions. When the transmembrane pressure difference reaches or exceeds the preset threshold, the maintenance cleaning is started to restore the transmembrane pressure difference to a low pressure level to ensure the long-term stable operation of the system; Step 4: Cleaning unit: connected to the reverse osmosis membrane assembly, used for maintenance cleaning under the instruction of the control system to remove pollutants attached to the surface of the membrane assembly and restore the flux and retention performance of the membrane assembly.

8. A seawater desalination system according to claim 7, characterized in that: The pretreatment unit also includes an automatic backwashing device, which can be automatically started periodically or according to water quality monitoring results to backwash the prefilter to remove impurities accumulated on the filter, thereby extending the service life of the prefilter and reducing maintenance costs.

9. A seawater desalination system according to claim 7, characterized in that: The cleaning unit adopts a combination of ultrasonic cleaning and chemical cleaning, wherein ultrasonic cleaning is used to preliminarily remove loose dirt on the surface of the membrane component, while chemical cleaning is used to deeply clean the stubborn contaminants in the membrane pores to ensure thorough cleaning of the membrane component and restore its performance.

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