A pervaporation seawater desalination and wastewater treatment membrane assembly, system and method

Abstract

The present invention provides a pervaporation seawater desalination and wastewater treatment membrane assembly, system, and method. The pervaporation seawater desalination and wastewater treatment membrane assembly includes a raw liquid flow channel layer, a middle vacuum layer, and a diaphragm support. Multiple middle vacuum layers and multiple raw liquid flow channel layers are alternately arranged between the end raw liquid flow channel layer and the fastening base. Diaphragm supports are provided on both end faces of the middle vacuum layer. A channel is provided between the diaphragm supports. A two-dimensional material diaphragm is provided between the middle vacuum layer and the raw liquid flow channel layer, and the two-dimensional material diaphragm faces the diaphragm support. A first seal and a second seal are provided at the contact surface between the raw liquid flow channel layer and the middle vacuum layer. A raw liquid flow channel is provided in the raw liquid flow channel layer to connect the raw liquid inlet and outlet. A vacuum channel is provided in the middle vacuum layer, and the vacuum channel is used to connect to a vacuum pumping device. The pervaporation seawater desalination and wastewater treatment membrane assembly is suitable for large-area two-dimensional material diaphragms, which helps promote the application of two-dimensional material diaphragms in the fields of pervaporation seawater desalination and wastewater treatment.

Description

Technical Field

[0001] The present invention belongs to the field of separation membrane water treatment, and in particular relates to a pervaporation seawater desalination and wastewater treatment membrane component, system and method. Background Art

[0002] Due to rapid population growth, rapid industrial development, and the failure to meet industrial wastewater discharge standards, freshwater shortages and water pollution are becoming increasingly prominent. Water scarcity is a major challenge facing society today. Amid this severe water crisis, the recycling of saline wastewater and the utilization of seawater can not only significantly alleviate the ecological pressure caused by polluted water bodies but also provide new water sources for the normal operation of human society. Therefore, obtaining large quantities of freshwater through seawater desalination and wastewater treatment technologies has become a hot topic in current scientific research. Seawater desalination and wastewater treatment technologies are effective solutions to water shortages and water pollution, selectively removing impurities such as metal ions from non-drinking water sources. Compared to traditional thermal technologies such as distillation, membrane desalination technology offers the advantages of low energy consumption and high efficiency, making it widely considered an attractive solution for seawater desalination and wastewater treatment. Pervaporation technology combines membrane permeation and evaporation, utilizes low-grade heat sources, and can treat ultra-high salinity wastewater. Its advantages include energy conservation, high efficiency, simple operation, and ease of scale-up, and has led to increasing research in the field of water treatment and desalination in recent years. At the same time, separation membranes based on two-dimensional materials stand out in the field of water treatment due to their excellent water flux, desalination rate and other properties.

[0003] Because conventional membrane modules cannot be directly applied to pervaporation technology, which differs from the driving forces behind membrane desalination and conventional wastewater treatment, research on membrane modules for pervaporation desalination is currently limited. Most existing pervaporation desalination technologies utilize plate-and-frame modules, which are complex structures. This significantly limits the application and development of pervaporation technology based on two-dimensional membranes in desalination and wastewater treatment. Therefore, designing pervaporation membrane modules that are compatible with the performance of two-dimensional membranes and establishing a pervaporation membrane module performance testing system are crucial to the development of pervaporation desalination technology.

[0004] Currently, plate-and-frame membrane modules have the following problems due to their own structure: (1) The design of the sealing system and the fastening system is relatively complex; (2) The process of installing the membrane in the module takes too long, and the sealing system is too complicated; (3) When the membrane is too thick, the assembly of the traditional plate-and-frame module becomes more difficult or even impossible; (4) When it is necessary to add membranes to increase the water yield, the shell and flow channel layer must be redesigned, which is too costly; (5) When faced with a low-concentration raw liquid, after the upper membrane works to separate the fresh water, the raw liquid concentration increases greatly after flowing tangentially from the membrane surface. When it passes through the bottom membrane, the bottom membrane cannot work normally. This flow channel design is only suitable for the medium to be treated with a high-concentration raw liquid, and its application range is relatively small. Summary of the Invention

[0005] The present invention provides a system and method. The design purpose of the pervaporation seawater desalination and wastewater treatment membrane component is to address the problem that there is a lack of pervaporation membrane component forms suitable for two-dimensional material membranes in the current seawater desalination and wastewater treatment markets.

[0006] In order to solve the above technical problems, the technical solution proposed in the present invention is: a osmotic evaporation seawater desalination and wastewater treatment membrane assembly, comprising an end raw liquid flow channel layer, a raw liquid flow channel layer, a middle vacuum layer, a diaphragm support body and a fastening base, with the end ends respectively being the end raw liquid flow channel layer and the fastening base, a raw liquid flow channel and a connecting hole for connecting the raw liquid flow channel and the middle vacuum layer are opened in the end raw liquid flow channel layer, multiple middle vacuum layers and multiple raw liquid flow channel layers are alternately arranged between the end raw liquid flow channel layer and the fastening base, diaphragm support bodies are set on both end faces of the middle vacuum layer, channels are set between the diaphragm support bodies in the same vacuum layer, a two-dimensional material diaphragm is set between the middle vacuum layer and the raw liquid flow channel layer, and the two-dimensional material diaphragm is facing the diaphragm support body; a first seal and a second seal are set on the contact surface of the raw liquid flow channel layer and the middle vacuum layer; a raw liquid flow channel is opened in the raw liquid flow channel layer to connect the raw liquid inlet and outlet, a vacuum channel is opened in the middle vacuum layer, and the vacuum channel is used to connect the vacuum pumping equipment.

[0007] Furthermore, the diaphragm support body is made of sand core or foam metal, the diaphragm support body is symmetrical about the middle vacuum layer, the diaphragm support body is cylindrical, and countersunk holes for installing the diaphragm support body are provided on both sides of the middle vacuum layer.

[0008] Furthermore, the stock liquid flow channels in the stock liquid flow channel layer are connected in parallel or in series; and the vacuum channels in the middle vacuum layer are connected in parallel or in series.

[0009] Furthermore, positioning pins and positioning holes are provided on the connection surfaces of the adjacent raw liquid flow channel layers and the middle vacuum layer, and bolt holes are evenly provided around the raw liquid flow channel layers and the middle vacuum layer.

[0010] Furthermore, polymer protective film layers are provided on both sides of the two-dimensional material membrane.

[0011] Furthermore, the first sealing member is located on the outer ring of the second sealing member, and both the first sealing member and the second sealing member are sealing rubber rings.

[0012] Furthermore, the direction of the raw liquid flow channel is parallel to the two-dimensional material membrane.

[0013] On the other hand, a pervaporation seawater desalination and wastewater treatment system is provided, comprising a heat source, a booster pump, a membrane assembly, a condenser and a vacuum pump; the raw liquid water source, the heat source, the booster pump, the raw liquid inlet of the membrane assembly, the condenser and the vacuum pump are connected in sequence, the concentrated water outlet of the membrane assembly is connected to the raw liquid water source, and the produced water outlet of the condenser is connected to a water storage device; the membrane assembly adopts the above-mentioned pervaporation seawater desalination and wastewater treatment membrane assembly.

[0014] The present invention further provides a pervaporation seawater desalination and wastewater treatment method. Based on the above-mentioned pervaporation seawater desalination and wastewater treatment system, the raw liquid is heated and pressurized and enters the pervaporation seawater desalination and wastewater treatment membrane assembly. Under the action of the pervaporation membrane, it passes through multiple stages of raw liquid flow channel layers and a middle vacuum layer in sequence or simultaneously. The water vapor that passes through the two-dimensional material membrane between the raw liquid flow channel layer and the middle vacuum layer passes through the membrane support body and then directly enters an external condenser under the action of the vacuum driving force to be condensed into water.

[0015] The present invention also provides a pervaporation seawater desalination and wastewater treatment test system, which is based on the pervaporation seawater desalination and wastewater treatment system mentioned above.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] Utilizing the properties of two-dimensional materials and their performance in desalination and wastewater treatment, the present invention is suitable for the form of pervaporation seawater desalination and wastewater treatment membrane components of large-area two-dimensional material membranes. A membrane support body is provided to play a supporting role to protect the two-dimensional material membrane from pressure damage. Water vapor that passes through the two-dimensional material membrane can quickly enter the condenser through the membrane support body. The membrane component structure is stable, not easy to damage, and easy to process and manufacture. The diversion state of the fluid can be adjusted by changing the external pipeline; the structure is simple, the installation is easy, and the sealing system is simple. The component design utilizes the seawater desalination and wastewater treatment performance of the two-dimensional material membrane, which helps to further promote the application of two-dimensional material membranes in the pervaporation seawater desalination and wastewater treatment industrial fields.

[0018] Furthermore, based on the structure of the present invention, the assembly can be quickly modified by increasing the number of raw liquid flow channel layers and vacuum layer plates, changing the external piping, and customizing the bolts. When the assembly's water output needs to be increased, this can be quickly completed by simply increasing the number of raw liquid flow channel layers and vacuum layer plates, changing the external piping, and customizing the bolts. This assembly has a wide range of applications and can adjust the fluid diversion state by changing the external piping. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the principle of a membrane module solution for pervaporation seawater desalination and wastewater treatment.

[0021] Figure 2 This is a schematic diagram of the principle of the second membrane component scheme for pervaporation seawater desalination and wastewater treatment.

[0022] Figure 3 This is a schematic diagram of the raw liquid flow channel layer at the end of the membrane module.

[0023] Figure 4 This is a schematic diagram of the raw liquid flow channel layer in the middle of the membrane module.

[0024] Figure 5 This is a schematic diagram of the central vacuum layer.

[0025] Figure 6 It is a schematic diagram of the membrane assembly fastening base.

[0026] Figure 7 Schematic diagram of the assembly of the diaphragm and the support body.

[0027] Figure 8 A test bench for the performance testing of seawater desalination and wastewater treatment components or a schematic diagram of a seawater desalination and wastewater treatment system.

[0028] In the accompanying drawings, 1-stock liquid flow channel layer, 2-middle vacuum layer, 3-diaphragm support body, 4-fastening base, 5-vacuum pipe, 6-stock liquid pipe, 7-two-dimensional material diaphragm, 8-positioning pin, 9-positioning hole, 10-bolt hole, 11-first groove, 12-second groove, 13-stock liquid flow channel, 14-vacuum channel. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0031] refer to Figure 1 、 Figure 2 and Figure 3 A pervaporation seawater desalination and wastewater treatment membrane assembly comprises a raw liquid flow channel layer 1, a middle vacuum layer 2, a membrane support 3 and a fastening base 4, with end raw liquid flow channel layers and a fastening base 4 at both ends, a raw liquid flow channel 13 and a connecting hole for connecting the raw liquid flow channel 13 and the middle vacuum layer 2 are provided in the end raw liquid flow channel layer, multiple middle vacuum layers 2 and multiple raw liquid flow channel layers 1 are alternately arranged between the two raw liquid flow channel layers 1, and membrane supports are provided on both end surfaces of the middle vacuum layer 2. A channel is set between the support body 3 and the diaphragm support body 3, a two-dimensional material diaphragm 7 is set between the middle vacuum layer and the raw liquid flow channel layer 1, and the two-dimensional material diaphragm 7 is opposite to the diaphragm support body 3; a first sealing member is set on the contact surface of the raw liquid flow channel layer 1 and the middle vacuum layer 2, and a second sealing member is set on the contact surface of the two-dimensional material diaphragm and the middle vacuum layer 2; a raw liquid flow channel 13 is opened in the raw liquid flow channel layer 1 to connect the raw liquid inlet and outlet, and a vacuum channel 14 is opened in the middle vacuum layer 2. The vacuum channel 14 is used to connect the vacuum pumping equipment. Figure 3 In the figure, (a), (b), and (c) are respectively the main view, bottom view, and three-dimensional view of the end raw liquid flow channel layer.

[0032] refer to Figure 4 , where (a), (b) and (c) are respectively the main view, top view and three-dimensional view of the raw liquid flow channel layer, positioning pins 8 and positioning holes 9 are set on the connecting surfaces of the adjacent raw liquid flow channel layer 1 and the middle vacuum layer 2, and bolt holes 10 are evenly opened around the raw liquid flow channel layer 1 and the middle vacuum layer 2.

[0033] As an optional embodiment, an end raw liquid flow channel layer is provided at one end of the pervaporation seawater desalination and wastewater treatment membrane assembly, and the outer end surface of the end raw liquid flow channel layer is not opened. A fastening base 4, a middle vacuum layer 2, a fastening base 4, a raw liquid pipeline 5 and a vacuum pipeline 6 are provided at the other end. The middle raw liquid flow channel layer 1 and the middle vacuum layer 2 are alternately arranged. The vacuum pipeline 6 is connected to the middle vacuum layer 2, and the raw liquid pipeline 5 is connected to the raw liquid flow channel layer 1. A positioning hole 9 and a bolt hole 10 are also provided on the fastening base 4. The positioning hole 9 is used to connect the positioning pin 8 of the adjacent layer. The structure of the fastening base 4 is referred to as Figure 6, where (a) and (b) are respectively a top view and a three-dimensional view of the fastening base.

[0034] refer to Figure 1 、 Figure 2 、 Figure 4 The two-dimensional thin film-based pervaporation seawater desalination and wastewater treatment membrane assembly provided by the present invention has a horizontal hole opened at the center of the raw liquid flow channel layer 1 to form a raw liquid flow channel 13, which then flows through the two-dimensional material membrane to work. A vacuum channel 14 is opened in the middle vacuum layer 2 to ensure that a vacuum driving force can be added, and a channel is added inside the middle vacuum layer 2, that is, below the membrane support body 3.

[0035] refer to Figure 1 , designing the raw liquid pipeline outside can increase the scope of use of the component. The different structures of the external raw liquid pipeline can change the diversion state of the raw liquid, and under different diversion states, it can be used for brine of different concentrations. The pipeline design in Scheme 1 allows the raw liquid to flow to the secondary membrane unit after working in the primary membrane unit, and so on, and finally complete the separation effect through all membrane units. Due to the action of the pervaporation membrane, the raw liquid concentration increases with each flow through the primary membrane unit, and the water flux of each membrane unit decreases step by step. When the raw liquid concentration is low, the raw liquid concentration around the first membrane unit is quite different from that of the last membrane unit. Under this condition, the membrane units ranked later produce very little water. The structure of this raw liquid pipeline is suitable for raw liquids with higher concentrations.

[0036] refer to Figure 2 The pipeline structure in Option 2 splits the raw liquid before it enters the membrane unit, allowing it to flow approximately evenly to each membrane unit. This results in a consistent raw liquid concentration and water flux in each membrane unit. This raw liquid pipeline structure is more widely applicable than Option 1.

[0037] A diaphragm support body is arranged in the middle vacuum layer to protect the two-dimensional material diaphragm, and the diaphragm support body is foam metal or sand core.

[0038] refer to Figure 5 , a first sealing groove 11 for installing a first seal is provided on the middle vacuum layer 2, and a second sealing groove 12 for installing a second seal is provided on the raw liquid flow channel layer 1. The structure of the raw liquid flow channel layer determines the distribution degree of the raw liquid entering the membrane cavity. At the same time, the raw liquid flow channel layer needs to withstand the impact of a large flow of raw liquid. Moreover, as the core of the entire membrane assembly, the membrane assembly structure is stable, not easy to be damaged, and easy to process and manufacture. Considering the problem of cooperation and sealing with the O-ring and the support layer, the various parts of the membrane assembly are designed as follows: The two-dimensional material diaphragm has limited ability to withstand pressure, and a diaphragm support body 3 is provided to play a supporting role to protect the two-dimensional material diaphragm from pressure damage, and the water vapor passing through the two-dimensional material diaphragm can quickly flow into the vacuum area through the diaphragm support body, and finally flow into the condenser to liquefy into water.

[0039] Optionally, the diaphragm support body may be made of a solid material such as a sand core that is strong and has good water permeability; as a preferred solution, a strong and hydrophobic foam metal may be selected as the diaphragm support body.

[0040] Optionally, the shape of the diaphragm support body 3 is set to be cylindrical, the diaphragm support body 3 is set in the two end surface countersunk holes of the middle vacuum layer, and a through hole is opened in the center of the middle vacuum layer, a first seal is set between the middle vacuum layers, a sealing gasket is set on the contact surface, and it is a double sealing system. The first seal is installed in the first groove 11. At this time, after the water vapor passes through the diaphragm support body, it directly enters the external condenser under the action of the vacuum driving force.

[0041] Preferably, a through hole is opened in the middle of the middle vacuum layer 2 for installing the diaphragm support body 3 to ensure that the volume of the membrane assembly is reduced, and a vacuum channel is opened in the middle vacuum layer 2 to reduce the complexity of the assembly, increase the integrity of the assembly, greatly reduce the number of parts, and increase the specific surface area.

[0042] During the operation of the membrane module, the main method for controlling membrane fouling and preventing concentration polarization is to promote the turbulent state of the mixed liquid on the membrane surface, so that it forms a relatively large shear force on the membrane surface, thereby controlling the formation of the impurity layer and preventing the high-concentration raw liquid from condensing on the membrane surface and causing huge osmotic pressure. The selection and control of the water flow pattern is very necessary. By changing the structural form of the membrane module, the water flow can be controlled to form a specific flow pattern, thereby forming favorable hydraulic conditions on the membrane surface that are conducive to controlling membrane fouling and concentration polarization, ultimately achieving the purpose of controlling membrane concentration polarization.

[0043] As a preferred implementation, adjustments are made to the fluid flow channel layer within the membrane module to adjust the inflow direction of the working fluid so that the fluid does not directly impact the membrane surface after entering the flow channel layer. Therefore, the flow channel is designed to be parallel to the membrane. Furthermore, changing the surface roughness of the flow channel can also increase turbulence and promote tangential flow.

[0044] The use of tangential flow to flush the membrane surface is a tangential flushing method, which is beneficial to the long-term operation of the membrane module. In addition, the tangential rotating inflow can flush the membrane surface, thereby destroying the concentration polarization, thinning the boundary layer, and improving the membrane flux. Since the membrane module adopts an alternating splicing assembly structure, after the alternating splicing assembly is completed, all membrane discs are fixed by custom bolts. On the one hand, this fastening method has a wide range of requirements for the thickness of the membrane, such as Figure 7 As shown, when the mechanical stability of the two-dimensional material membrane is poor, a polymer protective film can be added on both sides of the two-dimensional material membrane to protect the two-dimensional material membrane.

[0045] Preferably, the pervaporation device can be designed as a detachable plate-and-frame membrane assembly, which features a relatively simple structure and convenient operation. The ease of assembly and disassembly of the plate-and-frame membrane assembly makes cleaning and maintenance easier, not only reducing equipment investment and operating costs, but also allowing for simultaneous assembly of various membrane samples for performance testing. Furthermore, because the internal channels of the feed liquid flow path can be appropriately modified, the pressure drop is reduced, the linear velocity is increased, and the membrane assembly is less susceptible to clogging by foreign matter. The main operating principle is as follows: The raw liquid flows from the feed inlet into the inner cavity of the device, which is filled with the raw liquid flow path. Driven by vacuum pressure, the raw liquid undergoes desalination pervaporation with the two-dimensional material membrane to produce water vapor. Fresh water then flows from the interior of the membrane assembly into the condenser, where it is liquefied into water.

[0046] After the raw liquid flow channel layer is assembled with the limiting hole 9 on the middle vacuum layer through the protruding positioning pin 8, the sealing ring is tightened and compressed by the bolts running through the entire component to ensure its sealing. The raw liquid flows through the inside of the component and comes into direct contact with the two-dimensional material diaphragm. Driven by the vacuum driving pressure, it is vaporized into water vapor and enters the middle vacuum layer 2 through the diaphragm. The generated water vapor enters the vacuum pipe and finally enters the condenser to liquefy into water.

[0047] The middle vacuum layer Figure 5 As shown, (a), (b) and (c) are respectively the main view schematic diagram, the bottom view schematic diagram and the three-dimensional schematic diagram of the middle vacuum layer. The middle vacuum layer 2 is used to install the diaphragm support body 3, the sealing ring, and collect the permeated steam. The two-dimensional material diaphragm is tightly pressed between the middle vacuum layer 2 and the raw liquid flow channel layer 1 by bolt connection. Foam metal or sand core is set in the middle cylindrical pore of the middle vacuum layer as the diaphragm support body 3, which plays the role of supporting the diaphragm and protecting the diaphragm from axial deformation and rupture under the action of water pressure. At the same time, water vapor will enter the vacuum channel through the foam metal and accumulate, and eventually flow into the condenser. Annular grooves are set on both end faces of the middle vacuum layer 2, and a sealing ring is provided in the annular groove to prevent the external atmospheric pressure from affecting the sealing environment of the vacuum pipe.

[0048] The dimensions of each component of the membrane assembly are determined by the size of the two-dimensional diaphragm and the material's stress intensity. The stress to be sustained by the membrane assembly determines the component material and wall thickness, and the dimensions of each component are determined based on the size of the two-dimensional diaphragm. Each component of the membrane assembly must provide sufficient mechanical support for the membrane, effectively supporting the diaphragm and ensuring its function. The membrane assembly requires excellent mechanical, chemical, and thermal stability.

[0049] Optionally, a steel pipe with a diameter of 2 inches and a wall thickness of 0.89 mm is connected to the outside of the raw liquid flow channel layer, the middle vacuum layer, and the raw liquid flow channel layer to connect the alternating raw liquid flow channel layers and directly connect them to the vacuum layer, which greatly reduces the sealing system required for the membrane assembly and greatly shortens the installation time.

[0050] When designing a membrane module, selecting the appropriate compactness is crucial for improving membrane flux and delaying membrane fouling. Excessive compactness means the liquid won't have enough room to oscillate, turbulence will weaken, and contaminants will more easily settle between the membranes, increasing the thickness of the filter cake layer and affecting separation efficiency. Excessive compactness can reduce the economic efficiency of the membrane module, so a reasonable design is essential. The compactness of a membrane module can be controlled by selecting the appropriate height and spacing between the modules. The smaller the height and the closer the distance between the modules, the higher the compactness.

[0051] Furthermore, after the diaphragm disc is assembled, all the diaphragm discs are connected and fixed by four customized bolts. On the one hand, this fastening method has a wide range of requirements for the diaphragm thickness. When the mechanical stability of the two-dimensional diaphragm is poor, a polymer protective film can be added on both sides of the diaphragm to achieve the purpose of protecting the diaphragm; on the other hand, it greatly reduces the number of bolts, shortens the installation time, and prevents the occurrence of missing fastening when there are too many bolts.

[0052] After determining the size of the membrane module, determine the size of the external piping according to each dimension.

[0053] The performance of the pervaporation membrane module was tested to verify the rationality of the design and whether it could overcome concentration polarization, meet water production requirements, and perform efficient pervaporation seawater desalination and wastewater treatment. To overcome concentration polarization, the high-concentration layer close to the membrane must be reduced to reduce the driving pressure required for pervaporation. This required maintaining a high flow rate and using a pure NaCl solution as the test solution. Under non-circulating conditions, the configuration process was time-consuming and required a large container capacity, so a recyclable test system was designed.

[0054] The seawater desalination and wastewater treatment component performance test bench of the present invention is as follows Figure 8 As shown, it includes a heat source 21, a booster pump 22, a membrane assembly 23, a condenser 24, and a vacuum pump 25; the raw liquid water source, the heat source 21, the booster pump 22, the raw liquid inlet of the membrane assembly 23, the condenser 24, and the vacuum pump 25 are connected in sequence, the raw liquid outlet of the membrane assembly 23 is connected to the raw liquid water source, and the water outlet of the condenser 24 is connected to the water storage device; the water source to be treated is connected to the water inlet of the membrane assembly through the booster pump, the water vapor outlet of the membrane assembly is connected to the condenser and the vacuum pump, the hot side outlet of the condenser is provided with a water production container, the water outlet of the membrane assembly is connected to the water source to be treated, and a heating device is provided in the water source to be treated. The water to be treated is pumped into the membrane assembly by the booster pump, and the generated water vapor passes through the middle vacuum layer 2 into the vacuum pipe collection container, and the remaining salt solution refluxes into the feed port for recirculation. The vacuum gauge in the test device reflects the vacuum degree on the vacuum side of the diaphragm in the membrane assembly, measures the size of the vacuum driving force, and ensures that the working pressure is within the required range.

[0055] During the construction of the osmotic evaporation seawater desalination and wastewater treatment system or test system, it is not feasible to use an ordinary freshwater booster pump because the high-mass concentration salt water is severely corrosive. After the corrosion, the impeller of the booster pump is corroded, and the energy that can be supplied to the compressed fluid is reduced, resulting in a reduction in the boosting capacity of the booster pump and a reduction in the maximum pressure of the fluid in the pipeline, which cannot meet the test requirements. A corrosion-resistant diaphragm pump is selected. Due to the working characteristics of the diaphragm pump, its pressure cannot be stabilized. Then an energy buffer device, such as a more commonly used pulse damper for metering pumps, is installed to minimize the pulse energy, so that the internal pressure of the membrane component is relatively stable and the component performance test is carried out.

[0056] The heat exchange capacity of the condenser was considered during the selection process for each device. Due to the principles of pervaporation desalination and wastewater treatment, the membrane is separated by a saline solution on one side and a vacuum zone on the other. The vacuum is provided by a vacuum pump. If the condenser's heat exchange capacity is insufficient, water vapor can enter the vacuum pump and damage the equipment. The raw liquid flows from the feed inlet into the raw liquid channel layer, filling the inner cavity. It then flows through external piping to the next raw liquid channel layer. Inside the module, the raw liquid, driven by vacuum pressure, pervades the membrane element to produce water vapor. Under the influence of the vacuum pump within the test system, the water vapor inside the module enters the vacuum manifold within the test system due to the pressure differential. Finally, it is liquefied into liquid water in the condenser. However, due to test time requirements, the required raw liquid volume is relatively large. Without recirculation, the water tank would be too large, making it difficult to move the test bench. Therefore, the raw liquid needs to be recycled, and the raw liquid is pumped back into the feed inlet.

[0057] The specific operation process of the test and debugging phase is as follows:

[0058] Use deionized water to clean the seawater desalination and wastewater treatment components and the test bench, install the two-dimensional material diaphragm in the membrane component in advance, check that the component is well sealed, and then drain the accumulated liquid in the return pipe to reduce errors.

[0059] Prepare a NaCl solution with a concentration that meets the test requirements and place it in the stock liquid tank. Start the heat exchanger and condenser for pre-operation. Open the gate of the water supply tank, the circulation pipeline, and the valve of the water production pipeline. Close the drain valve of the water supply tank.

[0060] Turn on the power, start the booster pump to pump the raw liquid into the membrane module, monitor the inlet and outlet pressures of the membrane module, monitor the water production rate of the fresh water collection tank, and start measuring from startup to stable operation. The test time is set according to the designed water production capacity, and measurement is started and recorded from startup to stable operation.

[0061] Based on the same principle as the above embodiment, the membrane assembly and system of the present invention can also be used to treat wastewater, realize evaporation based on the osmosis phenomenon, and is suitable for treating wastewater containing pollutants such as heavy metals.

Claims

1. A pervaporation seawater desalination and wastewater treatment membrane assembly, characterized in that: The invention comprises an end raw liquid flow channel layer, a raw liquid flow channel layer (1), a middle vacuum layer (2), a diaphragm support body (3) and a fastening base (4), wherein the two ends are the end raw liquid flow channel layer and the fastening base (4), a raw liquid flow channel (13) and a connecting hole for connecting the raw liquid flow channel (13) and the middle vacuum layer (2) are provided in the end raw liquid flow channel layer, a plurality of middle vacuum layers (2) and a plurality of raw liquid flow channel layers (1) are alternately provided between the end raw liquid flow channel layer and the fastening base (4), and diaphragm support bodies are provided on both end surfaces of the middle vacuum layer (2). A support body (3) and a channel are provided between the diaphragm support body (3) in the same vacuum layer; a two-dimensional material diaphragm (7) is provided between the middle vacuum layer (2) and the raw liquid flow channel layer (1), and the two-dimensional material diaphragm (7) faces the diaphragm support body (3); a first sealing member and a second sealing member are provided on the contact surface between the raw liquid flow channel layer (1) and the middle vacuum layer (2); a raw liquid flow channel (13) is provided in the raw liquid flow channel layer (1) to connect the raw liquid inlet and outlet, and a vacuum channel (14) is provided in the middle vacuum layer (2), and the vacuum channel (14) is used to connect the vacuum pumping equipment.

2. The pervaporation seawater desalination and wastewater treatment membrane assembly according to claim 1, characterized in that: The diaphragm support body (3) is made of a sand core or foam metal. The diaphragm support body (3) is symmetrical about the middle vacuum layer (2) in the vertical direction. The diaphragm support body (3) is cylindrical. Countersunk holes for installing the diaphragm support body (3) are provided on both sides of the middle vacuum layer (2).

3. The pervaporation seawater desalination and wastewater treatment membrane assembly according to claim 1, characterized in that: The stock liquid flow channels in the stock liquid flow channel layer (1) are connected in parallel or in series; the vacuum channels in the middle vacuum layer (2) are connected in parallel or in series.

4. The pervaporation seawater desalination and wastewater treatment membrane assembly according to claim 1, characterized in that: Positioning pins (8) and positioning holes (9) are provided on the connection surfaces of the adjacent raw liquid flow channel layers (1) and the middle vacuum layer (2), and bolt holes (10) are evenly provided around the raw liquid flow channel layers (1) and the middle vacuum layer (2).

5. The pervaporation seawater desalination and wastewater treatment membrane assembly according to claim 1, characterized in that: Polymer protective film layers are provided on both sides of the two-dimensional material membrane (7).

6. The pervaporation seawater desalination and wastewater treatment membrane assembly according to claim 1, characterized in that: The first sealing member is located on the outer ring of the second sealing member, and both the first sealing member and the second sealing member are sealing rubber rings.

7. The pervaporation seawater desalination and wastewater treatment membrane assembly according to claim 1, characterized in that: The direction of the original liquid flow channel is parallel to the two-dimensional material diaphragm (7).

8. A pervaporation seawater desalination and wastewater treatment system, characterized in that: It comprises a heat source, a booster pump, a membrane assembly, a condenser and a vacuum pump; a raw liquid water source, a heat source (21), a booster pump (22), a raw liquid inlet of a membrane assembly (23), a condenser (24) and a vacuum pump (25) are connected in sequence, a concentrated water outlet of the membrane assembly (23) is connected to the raw liquid water source, and a produced water outlet of the condenser (24) is connected to a water storage device; the membrane assembly adopts the pervaporation seawater desalination and wastewater treatment membrane assembly described in any one of claims 1 to 7.

9. A pervaporation seawater desalination and wastewater treatment method, characterized in that: Based on the pervaporation seawater desalination and wastewater treatment system described in claim 8, the raw liquid is heated and pressurized and enters the pervaporation seawater desalination and wastewater treatment membrane assembly. Under the action of the pervaporation membrane, it passes through the multi-stage raw liquid flow channel layer (1) and the middle vacuum layer (2) in sequence or passes through the raw liquid flow channel layer (1) and the middle vacuum layer (2) at the same time. The water vapor that passes through the two-dimensional material membrane between the raw liquid flow channel layer (1) and the middle vacuum layer (2) passes through the membrane support body (3) and then directly enters the external condenser under the action of the vacuum driving force to be condensed into water.

10. A pervaporation seawater desalination and wastewater treatment test system, characterized in that: A pervaporation seawater desalination and wastewater treatment system based on claim 8.

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