Reverse osmosis seawater desalination membrane module, device and desalination method based on two-dimensional thin film

Abstract

The application provides a two-dimensional film-based reverse osmosis seawater desalination membrane assembly, device and desalination method, the membrane assembly comprises end membrane clamps, middle membrane clamps and membrane sheet supports, the two ends of the middle membrane clamps are sequentially provided with the membrane sheet supports and the end membrane clamps from near to far, and the end membrane clamps, the middle membrane clamps and the membrane sheet supports are provided with central holes; one end of a shell is provided with a concentrated water inlet, the other end is provided with a pure water outlet and a concentrated water outlet, a central collecting pipe and a plurality of membrane assemblies are arranged in the shell, the plurality of membrane assemblies are stacked along the shell to form a membrane stack, the central collecting pipe passes through the central holes of the membrane assemblies, the central collecting pipe is communicated with the pure water outlet, the properties of two-dimensional materials and the seawater desalination performance thereof are utilized, the reverse osmosis seawater desalination membrane assembly form is suitable for large-area two-dimensional material membranes, the membrane sheet supports are arranged to play a supporting role, so that the two-dimensional material membranes can resist pressure damage, and the application of the two-dimensional material membranes in the reverse osmosis seawater desalination industry is promoted.

Description

Technical Field

[0001] This invention belongs to the field of membrane water treatment, specifically relating to a reverse osmosis seawater desalination membrane module, device, and desalination method based on a two-dimensional membrane. Background Technology

[0002] Seawater desalination is the process of converting other energy sources (such as thermal, mechanical, and electrical energy) into brine separation energy. Separation membranes play a crucial role in membrane-assisted water treatment processes, determining the economic efficiency of the technology. Separation membrane technology is currently considered the most important membrane-assisted desalination technology and method; due to its effective desalination efficiency and reasonable energy consumption, it is making significant progress. Reverse osmosis seawater desalination technology, with its advantages of low investment cost and low energy consumption for water production, represents the mainstream development direction of future desalination technology, and its technological advancement depends on the development of membrane separation technology.

[0003] Aromatic polyamide thin-film composite membranes are currently the gold standard for reverse osmosis seawater desalination. Composed of a non-woven support layer, a porous intermediate polymer layer, and a thin (<500nm) highly cross-linked polyamide layer, it exhibits excellent permeability, high desalination capacity, and reasonable tolerance to a wide pH range and high pressure. However, despite these advantages, it still has some unavoidable drawbacks: aromatic polyamide thin-film composite membranes struggle to overcome the trade-off effect between water flux and desalination rate, cannot simultaneously achieve high permeability and selectivity, and have insufficient rejection of small and neutral solutes (such as boron in seawater and carcinogenic N-nitrosodimethylamine in wastewater). Furthermore, they are threatened and hindered by organic, inorganic, and microbial contaminants in the natural raw water.

[0004] Fortunately, two-dimensional materials have attracted widespread attention since the discovery of monolayer graphene. They are broadly defined as materials with bond strengths much greater in two dimensions than in three dimensions. The unusual properties and physical phenomena arising from these unique characteristics have sparked considerable research interest in their applications across various fields. In addition to charge transfer, atomically thin two-dimensional materials exhibit unique mass transfer properties. Ultra-high water flux is achieved through their atomic thickness, while high repulsion is achieved by controlling the introduction of defects. These two properties are desirable for different types of materials. Two-dimensional materials hold promise for overcoming the trade-off effect between desalination rate and water flux, making them candidate materials for next-generation reverse osmosis seawater desalination membranes.

[0005] The basic members of the two-dimensional materials family include graphene, MXene, and Ti3C2T. xTungsten disulfide, tungsten diselenide, and molybdenum disulfide (MoS2) are examples of materials used in two-dimensional (2D) nanosheet membranes. The rapid and precise molecular transport properties of these membranes stem from the inherent nanopores within the nanosheets and the nanochannels between the stacked nanosheets. 2D materials possess advantages such as high chemical stability, easy size control, high mechanical strength, and strong chemical adaptability, and have been widely used in membrane manufacturing. Layered 2D membranes are made from micron-sized 2D material sheets, forming an interlocking layered structure. They possess ideal characteristics for nanoscale filtration applications, including high surface hydrophilicity, mechanical strength, and flexibility. Benefiting from the abundant oxygen-containing functional groups on the surface of 2D materials, layered 2D membranes have strong functionalization potential and advantages in refined design and construction. Due to the hydrophobic nanochannels formed between the 2D material layers, layered 2D materials exhibit high water permeability, and the interlayer spacing can be controlled through physicochemical methods to regulate the size of the nanochannels, achieving a balance between high desalination efficiency and high throughput. High-performance membranes for water purification should possess characteristics such as high flux and high rejection rate. 2D reverse osmosis membranes are the most promising material to replace traditional reverse osmosis polymer membranes in the future.

[0006] Traditional polyamide reverse osmosis seawater desalination membranes are typically mounted in spiral-wound membrane modules. However, while two-dimensional materials possess higher mechanical strength, their toughness is lower than that of polymer materials, making direct mounting in spiral-wound membrane modules difficult. Therefore, the structure, performance, and cost of membrane modules are key factors restricting the widespread application of two-dimensional material membrane seawater desalination technology. Currently, no reverse osmosis membrane modules suitable for two-dimensional material membranes have been developed for the seawater desalination market. Therefore, developing reverse osmosis seawater desalination membrane modules suitable for two-dimensional material membranes, based on their physicochemical properties, is crucial for the application of two-dimensional material membranes in the seawater desalination market and the industrial development of seawater desalination. Summary of the Invention

[0007] The purpose of this invention is to address the current lack of suitable reverse osmosis membrane module forms for two-dimensional materials in the seawater desalination market, and to provide a reverse osmosis seawater desalination membrane module, device, and desalination method based on two-dimensional thin films.

[0008] To solve the above-mentioned technical problems, the technical solution proposed by the present invention is as follows: a reverse osmosis seawater desalination membrane module based on a two-dimensional membrane, including an end membrane clip, a middle membrane clip, and a membrane support. The membrane support and the end membrane clip are arranged sequentially from near to far at both ends of the middle membrane clip. A central hole is formed in the end membrane clip, the middle membrane clip, and the membrane support.

[0009] Furthermore, the diaphragm support is made of sand core or foam metal.

[0010] Furthermore, the end membrane clips and membrane supports are symmetrically arranged at both ends of the middle membrane clip.

[0011] Furthermore, the diaphragm support is frustum-shaped, and the diaphragm support and the end diaphragm clips are embedded in the middle diaphragm clips.

[0012] Furthermore, the diaphragm support is cylindrical and is located inside the middle diaphragm clip. The end diaphragm clips cover the end faces of the diaphragm support and the middle diaphragm clips, and sealing gaskets are provided on the contact surfaces of the end diaphragm clips and the middle diaphragm clips.

[0013] Meanwhile, a reverse osmosis seawater desalination device is provided, including a shell, with a concentrated water inlet at one end and a purified water outlet and a concentrated water outlet at the other end. A central manifold and multiple membrane modules are arranged inside the shell. The multiple membrane modules are stacked along the axial direction of the shell to form a membrane stack. The central manifold passes through the central hole of the membrane module and is connected to the purified water outlet. The membrane module adopts the above-mentioned reverse osmosis seawater desalination membrane module based on two-dimensional thin film.

[0014] Furthermore, an internal flow channel frame is provided inside the shell. The internal flow channel frame has a multi-layer structure, and the number of layers of the internal flow channel frame is the same as the number of membrane modules. There is a gap between the bottom surface of the internal flow channel frame and the ground inside the shell, and the central manifold passes through the center of the internal flow channel frame.

[0015] Furthermore, the central manifold adopts a spliced ​​structure, which includes a manifold connector and a manifold water collector. The manifold connector and the manifold water collector are alternately connected to form the central manifold. The manifold water collector is located in the membrane module, and water holes are opened on the side of the manifold water collector to communicate with the membrane module. The manifold connector has a groove in the middle to connect with the internal flow channel frame. The end of the manifold connector is sleeved in the manifold connector, and the end of the bottom manifold water collector is connected to the purified water outlet.

[0016] Furthermore, the shell adopts a split structure, which includes a cylindrical body, an upper end cover, and a lower end cover. Both the upper end cover and the lower end cover are fastened to the cylindrical body with bolts.

[0017] In addition, the present invention also provides a seawater desalination method. Based on the above-mentioned reverse osmosis seawater desalination device, concentrated water flows into the device from the feed port and fills the inner cavity. Under pressure, the concentrated water undergoes desalination and permeation with the membrane to obtain fresh water. The fresh water is collected from inside the membrane and enters the central manifold. Finally, the fresh water from multiple parallel membranes flows out from the fresh water outlet, while the concentrated water flows out from the concentrated water outlet.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: Utilizing the properties of two-dimensional materials and their seawater desalination performance, this invention is applicable to reverse osmosis seawater desalination membrane modules with large-area two-dimensional material membranes. By setting up a membrane support body, a supporting function is provided to protect the two-dimensional material membrane from pressure damage. Furthermore, the freshwater passing through the two-dimensional material membrane can quickly flow through the membrane support body into the central membrane clip 32. The membrane module structure is stable, not easily damaged, and easy to process and manufacture, maximizing the seawater desalination performance of the two-dimensional material membrane and further promoting the application of two-dimensional material membranes in the reverse osmosis seawater desalination industry. Attached Figure Description

[0019] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a parallel seawater desalination membrane module.

[0021] Figure 2 This is a schematic diagram of a membrane module.

[0022] Figure 3 This is a cross-sectional view of an example of a membrane module.

[0023] Figure 4 This is a structural diagram of a segmented connected central manifold.

[0024] Figure 5 This is an assembly diagram of the membrane module.

[0025] Figure 6 It is an end-membrane clip.

[0026] Figure 7 It is a middle membrane clip. Detailed Implementation

[0027] To facilitate understanding of the present invention, it will be described more fully and in detail with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0028] Unless otherwise defined, all technical terms used in this invention have the same meaning as commonly understood by those skilled in the art. The technical terms used in this invention are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention.

[0029] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0030] refer to Figure 2 and Figure 5 The reverse osmosis seawater desalination membrane module based on two-dimensional thin film provided by the present invention includes an end membrane clip 31, a middle membrane clip 32 and a membrane support 33. The membrane support 33 and the end membrane clip 31 are arranged sequentially from near to far at both ends of the middle membrane clip 32. A central hole is formed in the end membrane clip 31, the middle membrane clip 32 and the membrane support 33.

[0031] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 As shown, this invention discloses a novel two-dimensional material flat-sheet membrane reverse osmosis module, comprising a concentrate inlet 1, a shell 2, a membrane module 3, a central manifold 4, a purified water outlet 5, a concentrate outlet 6, a lower end cap 7, a gasket 8, an internal flow channel frame 9, bolts 10, and an upper end cap 11. The membrane module 3 includes end membrane clips 31, a middle membrane clip 32, and a membrane support 33. The central manifold 4 includes a manifold water collector 41 and a manifold connector 42, which are alternately connected to form the central manifold.

[0032] The structure of membrane module 3 determines the distribution of seawater entering the membrane cavity, and it needs to withstand the impact of large flow rates of seawater. As the core of the entire membrane module, the membrane module structure is robust, not easily damaged, and easy to manufacture. The issue of sealing the membrane cavity in conjunction with gaskets and support frames is considered. The design of each part of the membrane module is as follows: Since the two-dimensional material membrane has limited pressure resistance, a membrane support 33 is provided to support it and protect the two-dimensional material membrane from pressure damage. Fresh water passing through the two-dimensional material membrane can quickly flow through the membrane support 33 into the middle membrane clip 32 and finally into the central manifold 4.

[0033] The diaphragm support 33 can be made of a strong solid material such as sand core with a large water flux. Preferably, lightweight, strong and hydrophobic foam metal can be used as the diaphragm support.

[0034] Optionally, depending on the actual pressure in the membrane module, the shape of the membrane support 33 can be set to cylindrical when the pressure is low, as shown in the reference. Figure 5The diaphragm support 33 is cylindrical and is located inside the middle diaphragm clip 32. The end diaphragm clips 31 cover the end faces of the diaphragm support 33 and the middle diaphragm clip 32. A sealing gasket 34 is provided at the contact surface between the end diaphragm clip 31 and the middle diaphragm clip 32. Water, after passing through the diaphragm support, drips directly into the middle diaphragm clip 32 under gravity, increasing the freshwater flow rate and reducing water retention in the diaphragm support. However, when the pressure is too high and the cylindrical shape is insufficient to withstand the pressure, such as... Figure 2 As shown, the diaphragm support 33 is frustum-shaped, and the diaphragm support 33 and the end diaphragm clip 31 are embedded in the middle diaphragm clip 32. The diaphragm support 33 is designed to be frustum-shaped and fits perfectly with the middle diaphragm clip 32. The pressure is transmitted to the middle diaphragm clip 32 through contact with the middle diaphragm clip 32 to ensure its supporting function.

[0035] Preferably, the upper half of the middle membrane clip 32 is a cylinder with a truncated cone removed, which creates a slope for the flow of fresh water, ensuring that fresh water can flow more easily into the central manifold. A hole is left in the middle of the middle membrane clip 32 to connect and fix the central manifold, allowing fresh water to flow into the central manifold and ensuring rapid fresh water production.

[0036] During membrane module operation, the main method for controlling membrane fouling and preventing concentration polarization is to promote turbulence in the mixed solution on the membrane surface, creating significant shear forces to control the formation of an impurity layer and prevent high-concentration brine from condensing on the membrane surface and causing excessive osmotic pressure. Therefore, the selection and control of the water flow regime is crucial and essential. By changing operating conditions or the structure of the membrane module, specific flow regimes can be controlled to create favorable hydraulic conditions on the membrane surface, thus controlling membrane fouling and concentration polarization. Unsteady fluid flow refers to a flow system where the velocity, pressure, density, and other physical quantities of the fluid on each membrane surface change not only with position but also with time. Unsteady fluid flow is a practical technology with good enhancement effects, low energy consumption, and simple equipment. It greatly promotes the design of high-efficiency, fouling-resistant membrane modules that prevent concentration polarization. Compared with steady-state turbulence, unstable fluids can enhance filtration, increase flux, and effectively control membrane fouling, regardless of whether the flow is laminar or turbulent.

[0037] Preferably, grooves are designed on the upper sidewall of the membrane module to adjust the inflow direction of the working fluid, preventing it from directly impacting the membrane surface after being fed into the gap between the two membrane modules. In addition, using... Figure 6The end membrane clips, particularly the central cross-shaped section 312, also contribute to increasing turbulence and promoting tangential flow. When the working fluid is present, the membrane surface experiences significant pressure. When the working fluid is insufficient to fill the membrane module, the flow generates a relatively small negative pressure compared to the external environment, resulting in a positive pressure between the membrane and the central membrane clip 32. Prolonged operation under such conditions can damage the membrane. This tangential flow provides tangential scouring to the membrane surface, reducing the pressure and facilitating long-term operation. Furthermore, the inflow adjustment structure rotates tangentially along the membrane surface, generating eddies near the membrane. This tangential rotating inflow scours the membrane surface, disrupting concentration polarization, thinning the boundary layer, and ultimately increasing membrane flux.

[0038] The reverse osmosis seawater desalination membrane module based on two-dimensional material thin film includes a membrane stack composed of membrane modules and a housing 2. One end of the housing 2 is provided with a concentrate inlet 1, and the other end is provided with a purified water outlet 5 and a concentrate outlet 6. A central manifold 4 and multiple membrane modules are provided inside the housing 2. The multiple membrane modules are stacked along the axial direction of the housing 2 to form a membrane stack. The central manifold 4 passes through the central hole of the membrane module and is connected to the purified water outlet 5. The membrane module is the reverse osmosis seawater desalination membrane module based on two-dimensional thin film as described in any one of claims 1-5.

[0039] Preferably, the reverse osmosis unit can be designed as a detachable plate-and-frame membrane module, which has a simple structure, is easy to operate, and allows for individual membrane replacement. Furthermore, the easy assembly and disassembly of the plate-and-frame membrane module facilitates cleaning and maintenance. This not only helps reduce equipment investment and operating costs but also serves as a testing machine for simultaneously installing various membrane samples for performance testing. In addition, the cross-sectional area of ​​the feed liquid flow channel can be appropriately increased, resulting in a smaller pressure drop, higher linear velocity, and less susceptibility to clogging by foreign objects. Its structure and working principle are briefly described below: The parallel seawater desalination reverse osmosis seawater desalination unit consists of an inner cavity, concentrate inlet and outlet, central manifold, desalinate outlet, multiple membrane modules, and corresponding connecting seals. The main working principle is as follows: concentrated water flows into the inner cavity of the device through the feed port and fills the shell. Under pressure, the concentrated water undergoes desalination and permeation with the membrane to obtain fresh water. The fresh water is collected from inside the membrane module and enters the central manifold. Finally, the fresh water from multiple parallel membrane modules flows out from the fresh water outlet, while the concentrated water flows out from the concentrated water outlet.

[0040] As a preferred option, an internal flow channel frame 9 can be added to control the flow channel, increase the compactness of the membrane module, promote turbulence, and increase the flow velocity. The internal flow channel frame 9 has a multi-layer structure, and the number of layers of the internal flow channel frame 9 is consistent with the number of membrane modules. There is a gap between the bottom surface of the internal flow channel frame 9 and the inner ground of the shell 2. The central manifold 4 passes through the center of the internal flow channel frame 9, and the groove in the middle of the manifold connector 42 is embedded in the inner side of the internal flow channel frame 9.

[0041] End membrane clip structure such as Figure 6 As shown, a) is a schematic diagram of one side of the end membrane clamp, b) is a schematic diagram of the other side of the end membrane clamp, and c) is a three-dimensional schematic diagram of the end membrane clamp. The end membrane clamp is bolted to fix and seal the two-dimensional membrane between itself and the central membrane clamp. Concentrate flows over its surface, directly contacting the membrane through the gap in the central portion, and under pressure, passes through the membrane, generating desalinated water that flows into the central membrane clamp. The cross-shaped support structure of the end membrane clamp serves both a supporting function and a function of disturbing the water flow, reducing concentration polarization. Preferably, the thickness of the cross can be less than the thickness of the end membrane clamp; in this case, foam metal can be added under the cross to prevent excessively strong water flow from directly contacting and damaging the membrane.

[0042] refer to Figure 5 and Figure 7 The diaphragm can be clamped between end diaphragm clips and middle diaphragm clips by bolts. The end diaphragm clips and middle diaphragm clips have corresponding first circular recessed channels 313 and second circular recessed channels 322 for placing sealing gaskets to clamp the diaphragm in the middle. Sealing gaskets 34 are used to seal the two-dimensional material diaphragm, preventing the mixing of concentrated and desalinated water on both sides. As a preferred connection method, a first threaded hole 311 and a second threaded hole 321 can be formed on the end diaphragm clips 31 and middle diaphragm clips 32. The second threaded hole 321 has a groove larger than the diameter of the threaded hole to place a waterproof sealing gasket. The diaphragm is then secured by screwing the two clips together.

[0043] The middle membrane clip structure is as follows Figure 7 As shown, a) is a schematic diagram of one end face of the middle membrane clamp, b) is a cross-sectional schematic diagram of the middle membrane clamp, and c) is a three-dimensional schematic diagram of the middle membrane clamp. The middle membrane clamp serves to support the membrane and collect freshwater. The membrane is secured between the middle membrane clamp and the end membrane clamps using bolts. The cylindrical pores in the middle of the middle membrane clamp are typically filled with supporting materials such as foam metal or sand cores to support the membrane and prevent damage under water pressure. Simultaneously, freshwater accumulates in the foam metal and eventually flows into the central manifold. An annular groove 322 is provided on the middle membrane clamp, and a sealing ring is installed in the annular groove 322 to prevent external concentrated water from directly flowing into the central manifold.

[0044] The dimensions of each part of the membrane module are determined by the dimensions of the two-dimensional material diaphragm and the material stress intensity. After determining the wall thickness to meet the pressure the membrane module will withstand and the stress concentration caused by the connection and sealing, the dimensions of each part of the membrane module are determined based on the dimensions of the two-dimensional material diaphragm. The dimensions of each part of the membrane module are such that they provide sufficient mechanical support for the membrane, can effectively support the diaphragm and enable it to function properly, and have good mechanical, chemical, and thermal stability.

[0045] The shell 2 adopts a split structure, comprising a cylindrical body, an upper end cover 11, and a lower end cover 7. Both the upper end cover 11 and the lower end cover 7 are bolted to the cylindrical body, with gaskets in between for sealing. Firstly, as a pressure vessel, it must meet the strength requirements for pressure during membrane module production and operation, ensuring operational safety. Therefore, we need to determine the shell thickness and material based on the stress on the shell surface. Secondly, the inner diameter of the shell is mainly determined based on the dimensions of the membrane module. The inner diameter of the shell affects the flow state and pressure changes of the feed liquid, thus affecting the operation of the two-dimensional membrane. Therefore, it is necessary to reasonably determine the inner diameter of the shell and ensure that there are no dead zones in the liquid flow within the shell.

[0046] When designing membrane modules, choosing the appropriate compactness is crucial for improving membrane flux and delaying membrane fouling. Excessive compactness leaves insufficient space for liquid oscillation, reducing turbulence and allowing pollutants to deposit more easily between the membranes, increasing the filter cake thickness and affecting separation efficiency. Conversely, insufficient compactness leads to decreased economic efficiency. Therefore, a reasonable selection is essential. The compactness of membrane modules can be controlled by choosing appropriate module height and spacing. A smaller module height and closer spacing between modules result in a higher compactness.

[0047] After determining the appropriate membrane module size and spacing, the dimensions of the central collector are determined based on these two dimensions. The central collector can be designed as a single unit, with perforations in the tube to mate with the membrane module for freshwater collection. One end of the single-unit central collector is threaded and tightly connected to the housing via a sealing ring or other sealing element, and then secured with a nut. During tightening, the membrane module and bushing gasket are compressed to achieve sealing and isolation, ensuring freshwater production. Preferably, the central collector is designed as follows... Figure 4 As shown, the water collection components and the water collection pipe connectors are connected by threads, and multiple units are assembled together. They cooperate with the end membrane clamps and the middle membrane clamps to achieve the function of collecting fresh water and outputting the membrane module.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A reverse osmosis seawater desalination membrane module based on a two-dimensional thin film, characterized in that, The device includes an end membrane clip (31), a middle membrane clip (32), and a membrane support (33). The middle membrane clip (32) has the membrane support (33) and the end membrane clip (31) arranged sequentially from near to far at both ends. The end membrane clip (31), the middle membrane clip (32), and the membrane support (33) all have central holes. The end membrane clip (31) and the membrane support (33) are symmetrically arranged at both ends of the middle membrane clip (32). The membrane support (33) is made of sand core or... Made of foam metal; the diaphragm support (33) is frustum-shaped, and the diaphragm support (33) and the end diaphragm clip (31) are embedded in the middle diaphragm clip (32) or the diaphragm support (33) is cylindrical, the diaphragm support (33) is located inside the middle diaphragm clip (32), the end diaphragm clip (31) covers the end face of the diaphragm support (33) and the middle diaphragm clip (32), and a sealing gasket (34) is provided on the contact surface between the end diaphragm clip (31) and the middle diaphragm clip (32).

2. A reverse osmosis seawater desalination device, characterized in that, The device includes a housing (2), with a concentrated water inlet (1) at one end and a purified water outlet (5) and a concentrated water outlet (6) at the other end. A central manifold (4) and multiple membrane modules are provided inside the housing (2). The multiple membrane modules are stacked along the axial direction of the housing (2) to form a membrane stack. The central manifold (4) passes through the central hole of the membrane module and is connected to the purified water outlet (5). The membrane module is the reverse osmosis seawater desalination membrane module based on two-dimensional thin film as described in claim 1.

3. The reverse osmosis seawater desalination device according to claim 2, characterized in that, An internal flow channel frame (9) is provided inside the shell (2). The internal flow channel frame (9) is a multi-layer structure. The number of layers of the internal flow channel frame (9) is the same as the number of membrane modules. There is a gap between the bottom surface of the internal flow channel frame (9) and the inner ground of the shell (2). The central manifold (4) passes through the center of the internal flow channel frame (9).

4. The reverse osmosis seawater desalination device according to claim 3, characterized in that, The central manifold (4) adopts a splicing structure. The central manifold (4) includes a manifold water collection component (41) and a manifold connector (42). The manifold water collection component (41) and the manifold connector (42) are alternately connected to form the central manifold. The manifold water collection component (41) is located in the membrane module. Water holes are opened on the side of the manifold water collection component (41) to communicate with the membrane module. The manifold connector (42) has a groove in the middle to connect with the internal flow channel frame (9). The end of the manifold connector (42) is sleeved in the manifold water collection component (41). The end of the bottom manifold connector (42) is connected to the clean water outlet (5).

5. The reverse osmosis seawater desalination device according to claim 2, characterized in that, The shell (2) adopts a split structure. The shell (2) includes a cylinder, an upper end cover (11) and a lower end cover (7). The upper end cover (11) and the lower end cover (7) are fastened to the cylinder with bolts.

6. A method for seawater desalination, characterized in that, Based on the reverse osmosis seawater desalination device according to any one of claims 2-5, concentrated water flows into the device from the feed inlet and fills the inner cavity. Under pressure, the concentrated water undergoes desalination and permeation with the membrane to obtain fresh water. The fresh water is collected from inside the membrane and enters the central manifold. Finally, the fresh water from multiple parallel membranes is collected and flows out from the fresh water outlet, while the concentrated water flows out from the concentrated water outlet.

Images