A facilitated permeation spiral-wound membrane module and membrane separation method

Abstract

The application provides an assisted permeation roll type membrane assembly. Compared with the prior art, the assisted permeation roll type membrane assembly provided by the application can realize high concentration of raw liquid under low operating pressure; in addition, the membrane assembly can also be used in a forward osmosis membrane separation process. By introducing an assisted permeation liquid on the permeation liquid side of the RO or NF membrane in the assembly, the osmotic pressure on both sides of the membrane can be reduced, and then the pressure applied on the raw liquid side can be reduced, and the pressure can be regulated by adjusting the components of the assisted permeation liquid, so as to reduce the pressure and cost of solution concentration and improve the concentration ratio. The assisted permeation roll type membrane assembly provided by the application can be applied to industrial wastewater zero discharge, seawater desalination, material separation and other industrial fields, and can also be used as a forward osmosis, diffusion dialysis, gas separation, organic solvent nanofiltration and organic solvent reverse osmosis and other membrane separation processes in addition to reverse osmosis and nanofiltration.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation technology, and particularly relates to an auxiliary permeation membrane module and a membrane separation method. Background Technology

[0002] In fields involving the molecular-level separation of multiple components in mixtures, such as water treatment, industrial liquid material separation, and gas separation, membrane separation has gradually become an ideal technology.

[0003] In reverse osmosis (RO) and nanofiltration (NF) membrane separation processes, the feed solution and permeate are separated on both sides by the RO or NF membrane. The feed solution is pressurized, and some of the solvent permeates through the membrane to become the permeate, while most of the solute is concentrated in the remaining feed solution (concentrate). Because RO or NF membranes typically have a high rejection rate for solutes in the feed solution, the concentration of the feed solution is much higher than that of the permeate. According to the principle of osmotic pressure, if there is no external intervention, the permeate (low concentration) will actively diffuse through the membrane to the feed solution (high concentration); this process and phenomenon is called "osmosis." The magnitude of this chemical potential caused by the concentration gradient can be quantitatively expressed by osmotic pressure. When a certain pressure is applied to the feed solution side, and this pressure is greater than the aforementioned osmotic pressure, solvent molecules in the feed solution will permeate through the membrane into the permeate side, while the solute is retained by the membrane on the feed solution side; this process and phenomenon is called "reverse osmosis." It can be seen that during reverse osmosis, the solution concentration on the feed solution side gradually increases, and the corresponding osmotic pressure also continuously increases. When the osmotic pressure increases to the same level as the pressure applied to the feed solution side, osmosis stops, and this is called osmotic equilibrium. Nanofiltration membranes have larger pore sizes than reverse osmosis membranes, but the principles of the permeation process are similar.

[0004] It is evident that when using RO or NF membranes to concentrate solutions, there is always an upper limit to the concentration of the concentrate. During membrane separation, an osmotic pressure difference often forms across the membrane (the feed side and the permeate side), and this osmotic pressure difference increases with the concentration difference between the feed solutions. This leads to increased operating pressure, limited feed concentration ratio, and increased operating costs. For example, the currently relatively stable, operable, and highest operating pressure for RO or NF membranes is 8.5 MPa, which can concentrate sodium chloride to a maximum of 10 wt%. Even if the operating pressure is further increased to 16 MPa, sodium chloride can only be concentrated to 20 wt%. Clearly, such high operating pressure results in high energy consumption, higher pressure resistance ratings for pumps, pipelines, and valves, and increased safety risks.

[0005] To overcome the aforementioned problems, researchers have proposed models of osmosis-assisted technologies, including osmotic pressure-assisted RO technology, low-desalination-rate RO technology, and cascaded osmosis-regulated RO technology. However, reports on the transformation of these theoretical models into practical membrane modules or separation devices are extremely rare. Initially, researchers primarily used hollow fiber membrane modules, introducing two different feed solutions into the inner and outer sides of the hollow fibers, thus creating early osmosis-assisted membrane modules (hollow fiber modules). Subsequently, tubular and flat-sheet membrane stack osmosis-assisted membrane modules based on similar principles were invented. Although these tubular hollow fiber, tubular, and flat-sheet membrane stack osmosis-assisted membrane modules can achieve certain osmosis-assisted functions, they suffer from low unit pressure resistance, non-compact structure, and poor economic efficiency. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide an auxiliary permeation spiral wound membrane module with compact packing, strong pressure resistance, and easy automated continuous production, as well as the corresponding membrane separation technology.

[0007] This invention provides an auxiliary permeation spiral wound membrane module, comprising:

[0008] Central tube; the central tube has a hollow structure;

[0009] A plug is provided inside the central tube; the plug divides the central tube into a first section of the central tube and a second section of the central tube.

[0010] The first and second central tubes have holes in their walls; the ports at both ends of the central tubes can be used to introduce and export auxiliary permeation fluid, respectively.

[0011] A membrane bag is spirally wound around the outside of the central tube;

[0012] The membrane bag includes a first membrane, a flow guide net, and a second membrane arranged in sequence; the back sides of the first membrane and the second membrane are in contact with the flow guide net; the outer edges of the three sides of the first membrane, the flow guide net, and the second membrane are bonded together with adhesive, and an inlet and an outlet are respectively provided at both ends along the transverse direction of the central tube.

[0013] The edge of the opening side of the membrane bag is glued to the outer surface of the central tube.

[0014] Preferably, the diameter of the hole on the wall of the central tube is 0.5 to 5 mm; the number of holes on the wall of the first section of the central tube and the number of holes on the wall of the second section of the central tube are each 8 to 50 independently; the length of the plug core accounts for 0.1% to 90% of the total length of the central tube.

[0015] Preferably, the first membrane sheet, the flow guide net, and the second membrane sheet of the membrane bag are bonded together with adhesive along the direction of wrapping the central tube to form an adhesive line, which is used to separate the flow channels of the auxiliary permeate inside the membrane bag;

[0016] The flow channel of the auxiliary permeate inside the membrane bag is U-shaped or a wave-shaped structure composed of multiple U-shaped sections.

[0017] Preferably, the notch size of the flow channel at the adhesive line is 5 to 50 cm.

[0018] Preferably, the flow guiding mesh is composed of multiple layers of meshes with different pore sizes and pore structures, including at least an upper flow guiding fine mesh, a middle flow guiding coarse mesh, and a lower flow guiding fine mesh arranged sequentially.

[0019] Preferably, the pore size of the upper and lower fine mesh layers of the flow guide is independently 1 to 500 micrometers; the pore size of the middle coarse mesh layer of the flow guide is 100 to 1000 micrometers.

[0020] Preferably, the first membrane sheet and the second membrane sheet are each independently selected from reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, forward osmosis membrane, gas separation membrane or diffusion dialysis membrane; the thickness of the first membrane sheet and the second membrane sheet are each independently 10 to 500 micrometers.

[0021] Preferably, the number of film bags is 1 to 128; when the number of film bags is greater than or equal to 2, a spacer is provided between the connected film bags.

[0022] The present invention also provides a membrane separation method, comprising:

[0023] Use the above-mentioned auxiliary permeation spiral wound membrane module;

[0024] The feed solution to be treated is introduced into the inlet of the auxiliary permeate spiral wound membrane module, and the auxiliary permeate is introduced from one side of the central tube; the feed solution and the auxiliary permeate flow outside and inside the membrane bag respectively, and the feed solution and the auxiliary permeate flow in opposite directions, and the filtered feed solution is obtained from the outlet.

[0025] The present invention also provides a membrane separation device, including the above-described auxiliary permeation spiral wound membrane module.

[0026] This invention provides an auxiliary osmosis spiral wound membrane module, comprising: a central tube; the central tube having a hollow structure; a plug inside the central tube dividing the central tube into a first section and a second section; holes being provided on the walls of both the first and second sections of the central tube; a membrane bag spirally wound around the outside of the central tube; the membrane bag comprising a first membrane sheet, a flow guiding mesh, and a second membrane sheet arranged sequentially; the back sides of the first and second membrane sheets contacting the flow guiding mesh; the outer edges of the first membrane sheet, the flow guiding mesh, and the second membrane sheet being bonded together with adhesive, and having an inlet and an outlet respectively at both ends along the longitudinal direction of the central tube; the edge of the open side of the membrane bag being adhesively connected to the outer surface of the central tube. Compared with the prior art, the auxiliary osmosis spiral wound membrane module provided by this invention can achieve high concentration of the feed solution at a lower operating pressure; furthermore, this membrane module can also be used in forward osmosis membrane separation processes. By introducing an auxiliary permeate into the permeate side of the RO or NF membrane in the module, the osmotic pressure on both sides of the membrane can be reduced, thereby reducing the pressure applied to the feed solution side. This pressure can be controlled by adjusting the composition of the auxiliary permeate, achieving the purpose of reducing the pressure and cost of solution concentration and increasing the concentration ratio. The auxiliary permeate spiral wound membrane module provided by this invention can be applied to industrial fields such as zero discharge of industrial wastewater, seawater desalination, and material separation. In addition to reverse osmosis and nanofiltration, it can also be used for membrane separation processes such as forward osmosis, diffusion dialysis, gas separation, organic solvent nanofiltration, and organic solvent reverse osmosis. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the external appearance of the auxiliary permeation spiral wound membrane assembly provided by the present invention;

[0028] Figure 2 Schematic diagram of three different plugging lengths of the center tube structure for the auxiliary permeation spiral wound membrane module provided by the present invention;

[0029] Figure 3 Schematic diagram of membrane bags fabricated on three different plug lengths of the central tube provided by the present invention;

[0030] Figure 4 A cutaway structural diagram of the membrane bag provided by the present invention;

[0031] Figure 5 This is a schematic diagram of the structure of the auxiliary permeation spiral wound membrane module provided by the present invention;

[0032] Figure 6 This is a schematic diagram of the membrane separation device provided by the present invention;

[0033] Figure 7 This is a schematic diagram of the multi-stage membrane separation device provided by the present invention;

[0034] Figure 8 This is a schematic diagram of the multi-stage membrane separation device provided by the present invention;

[0035] Figure 9 This is a schematic diagram of the multi-stage membrane separation device provided by the present invention. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] This invention provides an auxiliary permeation spiral wound membrane module, comprising:

[0038] Central tube; the central tube has a hollow structure;

[0039] The central tube is equipped with a plug to divide the central tube into a first central tube section and a second central tube section.

[0040] The walls of the first and second central tubes are provided with holes; the ports at both ends of the central tubes can respectively introduce and export auxiliary permeation fluid.

[0041] A membrane bag is spirally wound around the outside of the central tube;

[0042] The membrane bag includes a first membrane, a flow guide net, and a second membrane arranged in sequence; the back sides of the first membrane and the second membrane are in contact with the flow guide net; the outer edges of the three sides of the first membrane, the flow guide net, and the second membrane are bonded together with adhesive, and an inlet and an outlet are respectively provided at both ends along the longitudinal direction of the central tube;

[0043] The edge of the opening side of the membrane bag is glued to the outer surface of the central tube.

[0044] See Figure 1 , Figure 1 This is a schematic diagram of the external appearance of the auxiliary permeation membrane module provided by the present invention, wherein 101 is the central tube, 102 is the outer shell, and 103 is the membrane bag.

[0045] The assisted permeation membrane module provided by this invention is a spiral wound assisted permeation membrane module, with a central tube at its center; see also Figure 2 , Figure 2This diagram illustrates the structure of three different plug-in lengths of the central tube; where 31 and 35 are the first section of the central tube, 32 and 36 are the plugs, 33 and 37 are the second section of the central tube, and 34 and 38 are the perforated structures. The material of the central tube can be any material well-known to those skilled in the art, and can be plastic or metal, without special limitations; the plastic can be one or more of ABS, polysulfone, polyetheretherketone, polyethersulfone, polyoxymethylene, polycarbonate, and polypropylene; the metal material can be stainless steel such as 304, 316L, 2205, and 2507, or aluminum alloy, titanium alloy, magnesium alloy, etc.; the central tube has a hollow structure; the inner diameter of the central tube is preferably 8–50 mm; the outer diameter of the central tube is preferably… The diameter is 14-80mm; a plug is provided inside the central tube to divide the central tube into a first section and a second section distributed laterally along the central tube; the plug is preferably a solid cylinder; the outer diameter of the plug is the same as the inner diameter of the central tube, so that the first section and the second section are not connected in the lateral direction; the position of the plug is preferably such that the lengths of the first section and the second section are equal; the length of the plug is preferably 0.1%-90% of the total length of the central tube; holes are provided on the tube walls of the first section and the second section; the diameter of the holes is preferably 0.5-5mm; the number of holes on the tube walls of the first section and the second section is preferably 8-50 each independently.

[0046] A membrane bag is spirally wound around the outside of the central tube; the edge of the membrane bag on the open side is adhesively connected to the outer surface of the central tube, preferably by adhesive, and then spirally wound around the outside of the central tube; see also Figure 3 , Figure 3This is a schematic diagram of the structure of membrane bags made from three different plugging core lengths of the central tube provided by the present invention. These three structures are only examples, and there are many other similar structures in practice. 201 is the first section of the central tube, 202 is the plugging core, 203 is the second section of the central tube, 204 is a small hole on the central tube, 205 is an adhesive line (located in the interlayer between the first and second membrane sheets), 206 is the first membrane sheet, 207 is the second membrane sheet, and 208 is the flow path of the auxiliary permeate in the membrane bag. The membrane bag includes a first membrane sheet, a flow guide net, and a second membrane sheet arranged sequentially. The first and second membrane sheets are each independently a reverse osmosis membrane, nanofiltration membrane, forward osmosis membrane, gas separation membrane, or diffusion dialysis membrane. The thickness of the first and second membrane sheets is preferably 10–500 micrometers. The back sides of the first and second membrane sheets are in contact with the flow guide net. The adhesive is applied in the interlayer between the first and second membrane sheets, holding the back sides of the two membrane sheets together. The outer edges of the three components—the membrane sheet, the flow guide net, and the flow guide mesh—are bonded together. The flow guide mesh preferably comprises a fine upper flow guide mesh, a coarse middle flow guide mesh, and a fine lower flow guide mesh arranged sequentially. This invention does not impose special limitations on the material of the flow guide mesh; it can be one or more of polypropylene, polyethylene, polyester, and nylon. The pore sizes of the fine upper and lower flow guide meshes are each independently 1–500 micrometers; the pore size of the coarse middle flow guide mesh is 100–1000 micrometers. The edges of the first membrane sheet, the flow guide mesh, and the second membrane sheet have inlet and outlet ports at both ends transversely along the central tube. To ensure uniform dispersion of the auxiliary permeate in the flow guide mesh, the first membrane sheet, the flow guide mesh, and the second membrane sheet of the membrane bag are bonded together with adhesive along the direction of wrapping the central tube to form an adhesive line. This adhesive line separates the flow channels of the auxiliary permeate within the membrane bag. The adhesive line has connection gaps at intervals on both sides when the membrane bag is unfolded, making the flow channels U-shaped or a wave-like shape composed of multiple U-shaped sections. See also... Figure 4 , Figure 4 The diagram below illustrates the cross-sectional structure of the membrane bag provided by the present invention, where 401 is the first membrane sheet, 402 is the second membrane sheet, 403 is the flow guiding mesh, 404 is an enlarged view of the flow guiding mesh, 4041 is the upper fine mesh for flow guiding, 4042 is the middle coarse mesh for flow guiding, 4043 is the lower fine mesh for flow guiding, and 405 is an adhesive line located in the interlayer between the two membrane sheets, bonding the back sides of the two membrane sheets and the flow guiding mesh.

[0047] In this invention, the number of membrane bags wrapped around the central tube can be one or more, preferably 1 to 128; when the number of membrane bags is greater than or equal to two, a spacer is preferably provided between the connected membrane bags, that is, the membrane bags adhered to the central tube on one side are alternately stacked with the spacer, and then spirally wound to form the membrane bag; see also Figure 5 , Figure 5This is a schematic diagram of the structure of the auxiliary permeate membrane module provided by the present invention, wherein 501 is the first central tube, 502 is the plug, 503 is the second central tube, 504 is the first membrane sheet, 505 is the second membrane sheet, 506 is the spacer, 507 is the adhesive line, 508 is the flow channel and route of the auxiliary permeate in the membrane bag in the example, and 509 is the flow channel and route of the feed liquid in the membrane module.

[0048] In this invention, a mesh spacer (hereinafter referred to as "mesh") is further included; the mesh spacer is laid alternately with the membrane bag and then wound together with the membrane bag onto the central tube. This invention does not impose any special limitations on the material of the mesh spacer, which can be one or more of polypropylene, polyethylene, polyester, and nylon.

[0049] In this invention, the auxiliary permeation spiral wound membrane assembly further includes an outer shell disposed outside the membrane bag; the outer shell is preferably a fiberglass shell or a stainless steel shell.

[0050] The auxiliary permeate spiral wound membrane module provided by this invention can achieve high concentration of feed solution at a relatively low operating pressure. Furthermore, this membrane module can also be used in forward osmosis membrane separation processes. By introducing an auxiliary permeate into the permeate side of the RO or NF membrane in the module, the osmotic pressure across the membrane can be reduced, thereby reducing the pressure applied to the feed solution side. This pressure can be controlled by adjusting the composition of the auxiliary permeate, achieving the goal of reducing the pressure and cost of solution concentration and increasing the concentration ratio. The auxiliary permeate spiral wound membrane module provided by this invention can be applied in industrial fields such as zero discharge of industrial wastewater, seawater desalination, and material separation. Besides reverse osmosis and nanofiltration, it can also be used in membrane separation processes such as forward osmosis, diffusion dialysis, gas separation, organic solvent nanofiltration, and organic solvent reverse osmosis.

[0051] This invention also provides a membrane separation method, comprising: using the above-described auxiliary permeation spiral wound membrane module; introducing the feed solution to be treated from the inlet of the auxiliary permeation spiral wound membrane module, and introducing the auxiliary permeate from one side of the central tube; the feed solution and the auxiliary permeate flowing outside and inside the membrane bag, respectively, and the feed solution and the auxiliary permeate flowing in opposite directions, and obtaining the filtered feed solution from the outlet. When the feed solution is pressurized, part of the solvent permeates through the membrane, enters the membrane bag and mixes with the auxiliary permeate, and is discharged from the other side of the central tube, thereby concentrating the feed solution and diluting the auxiliary permeate.

[0052] In this invention, the liquid to be processed is introduced into the membrane bag through the inlet, distributed in the membrane bag by the guide net, and then flows out from the outlet.

[0053] After the auxiliary permeate is introduced through one side of the central tube, it is dispersed through the pore structure of the central tube wall into the gap between the central tube and the membrane bag, as well as the gap formed when the membrane bag is wrapped. After flowing in the gap, it enters the central tube through the pore structure of the other side of the central tube wall and is discharged through the other side of the central tube.

[0054] In a further preferred embodiment, the auxiliary permeate is introduced through one side of the central tube and then dispersed into the mesh septum through the pore structure of the central tube wall. After flowing within the mesh septum, it enters the central tube through the pore structure of the other side of the central tube wall and is discharged through the other side of the central tube.

[0055] The pressure of the auxiliary permeation fluid is preferably -0.1 to 0.1 MPa; the pressure of the feed liquid to be filtered is preferably 0 to 8.5 MPa.

[0056] The present invention also provides a membrane separation device, including the above-described auxiliary permeation spiral wound membrane module.

[0057] See Figure 6 , Figure 6 This is a schematic diagram of the membrane separation device provided by the present invention.

[0058] In this invention, the membrane separation device further preferably includes a high-pressure pump; the high-pressure pump is connected to the inlet of the membrane bag in the auxiliary permeate membrane module; the feed liquid to be treated is input into the auxiliary permeate spiral wound membrane module via the high-pressure pump.

[0059] In this invention, it is further preferably included as a crystallization device; the outlet of the membrane bag is connected to the crystallization device, and the liquid to be treated is concentrated in the auxiliary permeation spiral wound membrane module, and the concentrated liquid enters the crystallization device to obtain crystalline solid by cooling crystallization or evaporation crystallization.

[0060] In this invention, it is further preferably included as a reverse osmosis membrane module; one side of the central tube is connected to the reverse osmosis membrane module; the auxiliary permeate is diluted after passing through the auxiliary permeate spiral wound membrane module, and the diluted auxiliary permeate is concentrated in the reverse osmosis membrane module and can be recycled, and its produced water meets the discharge standards or is used for production and domestic use.

[0061] The membrane separation device provided by the present invention can have one or more auxiliary permeation spiral wound membrane modules; when the number of auxiliary permeation spiral wound membrane modules is one, the membrane separation device is a single-stage membrane separation device; when the number of auxiliary permeation spiral wound membrane modules is multiple, the membrane separation device is a multi-stage membrane separation device.

[0062] When the membrane separation equipment is a multi-stage membrane separation equipment, the multiple auxiliary permeate spiral wound membrane modules are connected in series. The outlet of the membrane bag of the first auxiliary permeate spiral wound membrane module is connected to the inlet of the membrane bag of the second auxiliary permeate membrane module, and so on. The feed solution to be treated is pressurized by a high-pressure pump and introduced into the first-stage auxiliary permeate spiral wound membrane module. The permeate enters the back side of the membrane and mixes with the auxiliary permeate, diluting it. The concentrate is pressurized again by the high-pressure pump and introduced into the second stage, then the third stage, and so on, up to the Nth stage. Finally, the concentrate undergoes energy recovery, cooling crystallization, or evaporation crystallization to obtain a solid. See also Figure 7 , Figure 7 This is a schematic diagram of the multi-stage membrane separation device provided by the present invention.

[0063] When the membrane separation equipment is a multi-stage membrane separation equipment, the reverse osmosis membrane module can be one or more.

[0064] When there is only one reverse osmosis membrane module, multiple auxiliary spiral wound membrane modules share one reverse osmosis membrane module. The central tubes of adjacent auxiliary spiral wound membrane modules are connected, preferably through a circulation pump. The auxiliary permeate flows out of the central tube of the previous auxiliary spiral wound membrane module and is then introduced into the central tube of the next auxiliary spiral wound membrane module for recycling. The flow direction of the auxiliary permeate is opposite to the flow direction of the feed liquid to be treated, that is, the multi-stage membrane separation equipment is an N-stage membrane separation equipment (N is preferably less than or equal to 6). The feed liquid to be treated is pressurized by a high-pressure pump and then introduced into the first stage. In a reverse osmosis spiral wound membrane module, the concentrate is repressurized by a high-pressure pump and introduced into the second stage, then the third stage, and so on, up to the Nth stage. The concentrate is finally purified through energy recovery, cooling crystallization, or evaporation crystallization to obtain a solid. The N-stage membrane modules in the system share a single auxiliary permeate stream. This stream enters from the Nth stage membrane module and is sequentially pumped to the (N-1)th stage, then back to the first stage, by a circulation pump. The resulting large volume of diluted auxiliary permeate is then treated by a reverse osmosis membrane, producing treated water that meets discharge standards or is used for production and domestic purposes. The concentrated auxiliary permeate is recycled. The auxiliary permeate in this process can be of the same composition as the feed solution to be treated. See also... Figure 8 , Figure 8 This is a schematic diagram of the multi-stage membrane separation device provided by the present invention.

[0065] When there are multiple reverse osmosis membrane modules, the number of reverse osmosis membrane modules is preferably the same as the number of auxiliary osmosis spiral wound membrane modules. The feed solution to be treated is pressurized by a high-pressure pump and introduced into the first-stage auxiliary osmosis spiral wound membrane module. The permeate enters the back side of the membrane and mixes with the auxiliary permeate, diluting it. The concentrate is pressurized again by the high-pressure pump and introduced into the second stage, then the third stage, and so on, up to the Nth stage. The concentrate is finally subjected to energy recovery, cooling crystallization, or evaporation crystallization to obtain a solid. The permeate from each stage is mixed and diluted with the auxiliary permeate, then treated by the reverse osmosis membrane, producing water that meets discharge standards or for production and domestic use. The concentrated auxiliary permeate is recycled. In this process, the auxiliary permeate in each stage can be a feed solution with the same composition as the feed solution to be treated in each stage.

[0066] When the auxiliary permeate has the same composition as the feed solution to be treated, the membrane separation equipment preferably further includes a nanofiltration membrane module; the nanofiltration membrane module is connected to the central tube of the auxiliary permeate spiral wound membrane module (the side of the central tube from which the auxiliary permeate flows out is connected); the auxiliary permeate passes through the auxiliary permeate spiral wound membrane module and then enters the nanofiltration membrane module, where it is concentrated and can be returned as the feed solution to be treated for recycling. See also Figure 9 , Figure 9 This is a schematic diagram of the multi-stage membrane separation device provided by the present invention.

[0067] To further illustrate the present invention, the following describes in detail an auxiliary permeation membrane module and membrane separation method provided by the present invention with reference to embodiments.

[0068] All reagents used in the following examples are commercially available.

[0069] Example 1

[0070] The filter material is a polyamide reverse osmosis membrane with a width of 1067 mm, a desalination rate of 99.8%, and a water flow rate of 46 liters / (square meter·hour). The filter consists of an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes and 16 holes in the tube wall), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive as structural components.

[0071] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0072] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 6 The test was conducted on the primary auxiliary reverse osmosis spiral wound membrane module test system shown. The auxiliary permeate (feed solution 1) was an 8 wt% sodium chloride solution. The feed solution (feed solution 2) was a 10 wt% sodium chloride solution. The system operated at room temperature and a pressure of 6.5 MPa. After filtration began, the concentration of feed solution 1 decreased after passing through the membrane, and was then concentrated using a conventional reverse osmosis membrane to reach a concentration of 8 wt%. The volume of the feed solution gradually decreased while its concentration gradually increased. The concentrations of both feed solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the remaining volume of feed solution 2 was 290 L, with a concentration of 18.4 wt%.

[0073] Example 2

[0074] The filter material is a polyamide reverse osmosis membrane with a width of 1067 mm, a desalination rate of 99.5%, and a water flow rate of 56 liters / (square meter·hour). The filter consists of an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes and 16 holes in the tube wall), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive as structural components.

[0075] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 31 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 38.6 m². 2 .

[0076] After the membrane module prepared above was cured at room temperature for 24 hours, the resulting membrane module... Figure 6 The test was conducted on the primary auxiliary permeate spiral wound membrane module testing system shown. The auxiliary permeate solution (feed solution 1) was a 10 wt% sodium chloride solution. The test feed solution (feed solution 2) was a 10 wt% sodium chloride solution, totaling 1000 L. The system was operated at room temperature and a pressure of 7.5 MPa. After the filtration operation began, the volume of the feed solution (feed solution 2) gradually decreased while its concentration gradually increased; the concentrations of both feed solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the remaining volume of the feed solution was 483 L, with a concentration of 20.7 wt%.

[0077] Example 3

[0078] The filter material is a polyamide reverse osmosis membrane with a width of 1067 mm, a desalination rate of 99.8%, and a water flow rate of 46 liters / (square meter·hour). The filter consists of an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes and 16 holes in the tube wall), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive as structural components.

[0079] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0080] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 7 The multi-stage assisted permeate spiral wound membrane module was tested on a process system with two-stage membrane modules. The feed solution (feed solution 2) was a 10 wt% sodium chloride solution. The first-stage assisted permeate was an 8 wt% sodium chloride solution, and the second-stage assisted permeate was a 15 wt% sodium chloride solution. Operation was carried out at room temperature, with a fixed operating pressure of 6.5 MPa for each stage. After filtration began, the volume of the feed solution (feed solution 2) gradually decreased while its concentration gradually increased; the concentrations of both feed solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the concentration of feed solution 2 was 17.8 wt%.

[0081] Example 4

[0082] The filter material is a polyamide reverse osmosis membrane with a width of 1067 mm, a desalination rate of 99.8%, and a water flow rate of 46 liters / (square meter·hour). The structural components are an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes and 16 holes in the tube wall), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive.

[0083] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0084] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 7 The test was conducted on a multi-stage assisted osmosis spiral wound membrane module system, which features a three-stage membrane module. The feed solution (feed solution 2) was a 10 wt% sodium chloride solution. The first-stage assisted osmosis solution was 8 wt% sodium chloride, the second-stage was 15 wt% sodium chloride, and the third-stage was 25 wt% sodium chloride. The system operated at room temperature, with a fixed operating pressure of 6.5 MPa for each stage. After filtration began, the concentration of the first-stage assisted osmosis solution decreased, then was concentrated by the reverse osmosis membrane to reach a new concentration of 8 wt%; the second-stage assisted osmosis solution decreased, then was concentrated by the reverse osmosis membrane to reach a new concentration of 15 wt%; and the third-stage assisted osmosis solution decreased, then was concentrated by the reverse osmosis membrane to reach a new concentration of 25 wt%. The volume of the feed solution (feed solution 2) gradually decreased while its concentration gradually increased; the concentrations of both feed solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the concentration of feed solution 2 was 25.6 wt%.

[0085] Example 5

[0086] The filter material is a polyamide reverse osmosis membrane with a width of 1067 mm, a desalination rate of 90.2%, and a water flow rate of 66 liters / (square meter·hour). The structural components are an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes on the tube wall and 16 holes), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive.

[0087] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0088] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 8 The multi-stage assisted osmosis spiral wound membrane module was tested on a process system, which consists of three membrane modules. The feed solution (feed solution 2) is a 10 wt% sodium chloride solution. The assisted permeate is the feed solution pretreated by ultrafiltration, with a sodium chloride concentration still of 10 wt%. Operation was carried out at room temperature, with the operating pressure of each stage fixed at 7.5 MPa. After filtration began, the assisted permeate entered the membrane system from the third stage, exited from the first stage, and was then concentrated by the reverse osmosis membrane to reach a concentration of 10 wt%. The concentration of the assisted permeate in the second stage decreased, and was then concentrated by the reverse osmosis membrane to reach a concentration of 15 wt%. The concentration of the assisted permeate in the third stage decreased, and was then concentrated by the reverse osmosis membrane to reach a concentration of 10 wt%. After reaching osmotic equilibrium, the concentration of feed solution 2 was 22.4 wt%.

[0089] Example 6

[0090] The filter material is a polyamide nanofiltration membrane with a width of 1067 mm, a sodium chloride desalination rate of 90%, and a water flow rate of 72 liters / (square meter·hour). The structural components are an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes on the tube wall and 16 holes), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive.

[0091] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0092] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 7 The multi-stage assisted permeate spiral wound membrane module was tested on a process system shown, which consisted of three membrane modules. The feed solution (feed solution 2) was a 10 wt% sodium chloride solution. The first-stage assisted permeate was an 8 wt% sodium chloride solution, the second-stage assisted permeate was a 15 wt% sodium chloride solution, and the third-stage assisted permeate was a 25 wt% sodium chloride solution. The system operated at room temperature, with a fixed operating pressure of 7.5 MPa for each stage. After filtration began, the volume of the feed solution (feed solution 2) gradually decreased while its concentration gradually increased; the concentrations of both feed solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the concentration of feed solution 2 was 28.2 wt%.

[0093] Example 7

[0094] The filter material is a polyamide nanofiltration membrane with a width of 1067 mm. It has a sodium chloride desalination rate of 70%, a sodium sulfate rejection rate of 98%, and a water flow rate of 72 liters / (square meter·hour). The structural components are an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes and 16 holes in the tube wall), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive.

[0095] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0096] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 7 The multi-stage assisted permeate spiral wound membrane module was tested on a process system shown, which consists of three membrane modules. The feed solution (feed solution 2) was a 10 wt% sodium sulfate solution. The first-stage assisted permeate was a 10 wt% sodium sulfate solution, the second-stage assisted permeate was a 10 wt% sodium sulfate solution, and the third-stage assisted permeate was a 10 wt% sodium sulfate solution. The system operated at room temperature, with a fixed operating pressure of 7.5 MPa for each stage. After filtration began, the volume of the feed solution (feed solution 2) gradually decreased while its concentration gradually increased; the concentrations of both feed solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the concentration of feed solution 2 was 28.2 wt%.

[0097] Example 8

[0098] The filter material is a polyamide reverse osmosis membrane with a width of 1067 mm, a sodium chloride desalination rate of 99.6%, and a water flow rate of 42 liters / (square meter·hour). The structural components are an ABS resin injection-molded central tube (1016 mm in length, 10 mm in inner diameter, 16 mm in outer diameter, with 2 mm diameter holes and 16 holes in the tube wall), a polypropylene woven mesh (1067 mm in width and 0.5 mm in pore size), a PET flow guide mesh (1067 mm in width and 0.5 mm in pore size), and a two-component polyurethane adhesive.

[0099] Membrane module fabrication steps: First, wrap one end of the pre-cut flow guide net around the central tube, wrapping it 4 times. The remaining unwrapped flow guide net at the other end is about 1000mm long. Use ultrasonic welding to fix the wrapped flow guide net to the central tube. Second, place a flattened membrane fold sheet and a flow guide net sheet on the flow guide net in sequence, and apply a two-component polyurethane adhesive (U-shaped + middle half straight line). Repeat the steps of "place a membrane fold sheet, a flow guide net sheet, and apply two-component adhesive" 7 times. Finally, place another membrane fold sheet but without the flow guide net, and apply two-component adhesive. Third, using the central tube as an axis, spirally roll up the membrane fold sheet and flow guide net to form a roll, obtaining a membrane blank. Wrap the membrane blank tightly with tape. Fourth, wrap glass fiber around the membrane blank, cast epoxy resin, cure at room temperature, and test. The membrane fold sheet is formed by folding the membrane sheets face to face, resulting in a fold sheet 1076 mm wide and 1000 mm long. A mesh insert, 1067 mm wide and 1000 mm long, is sandwiched between the fold sheets. Calculations show that the effective membrane area of ​​this component is approximately 8.8 m². 2 .

[0100] After the membrane module prepared above was cured at room temperature for 48 hours, the resulting membrane module... Figure 9The multi-stage assisted reverse osmosis spiral wound membrane module application process device system shown was tested. This device is equipped with a three-stage membrane module. The feed solution (feed solution 2) is a 10 wt% sodium chloride solution. The first-stage auxiliary permeate is a 10 wt% sodium chloride solution. After being diluted, the auxiliary permeate is concentrated to 10 wt% using a conventional reverse osmosis membrane and recycled. Its permeate meets discharge or usage standards. The concentrated solution from the first stage is pumped to both sides of the second-stage auxiliary reverse osmosis spiral wound membrane module by a high-pressure pump and a circulation pump. The resulting permeate is concentrated by a nanofiltration membrane and recycled. The nanofiltration permeate is returned to the first stage as the feed solution. The concentrated solution from the second stage is used as both the feed solution and auxiliary permeate for the third stage. The concentrated solution from the third stage is used for crystallization treatment. The auxiliary permeate from the third stage is treated by a nanofiltration membrane to maintain a constant concentration. The nanofiltration permeate is introduced into the second stage as the feed solution. The system operates at room temperature, and the operating pressure of each stage is fixed at 5.5 MPa. After the filtration operation started, the volume of the stock solution (solution 2) gradually decreased and the concentration gradually increased; the concentrations of both solutions were monitored online using a conductivity meter. After reaching osmotic equilibrium, the concentration of solution 2 was 33.3 wt%.

Claims

1. An assisted permeate spiral-wound membrane module, characterized in that, The application relates to an auxiliary permeation coiled membrane assembly. The auxiliary permeation coiled membrane assembly comprises a center pipe; the center pipe is a hollow structure; the inner diameter of the center pipe is 8-50 mm; and the outer diameter of the center pipe is 14-80 mm. A plug core is arranged in the center pipe; the plug core divides the center pipe into a first section of the center pipe and a second section of the center pipe; the outer diameter of the plug core is the same as the inner diameter of the center pipe, so that the first section of the center pipe and the second section of the center pipe are not communicated in the transverse direction; and the position of the plug core makes the length of the first section of the center pipe equal to the length of the second section of the center pipe. Holes are arranged on the pipe wall of the first section of the center pipe and the second section of the center pipe; and the ports at the two ends of the center pipe can respectively guide auxiliary permeation liquid into and out. A membrane bag is spirally wound outside the center pipe. The membrane bag comprises a first membrane page, a flow guide net and a second membrane page which are arranged in sequence; the back surfaces of the first membrane page and the second membrane page are in contact with the flow guide net; the outer edges of the three surfaces of the first membrane page, the flow guide net and the second membrane page are bonded by an adhesive, and liquid inlets and liquid outlets are respectively arranged at the two ends of the transverse direction of the center pipe. The edge of the opening side of the membrane bag is adhesively connected with the outer surface of the center pipe. The diameter of the holes on the pipe wall of the center pipe is 0.5-5 mm; the number of the holes on the pipe wall of the first section of the center pipe and the second section of the center pipe is independently 8-50; and the length of the plug core accounts for 0.1%-90% of the total length of the center pipe. The first membrane page, the flow guide net and the second membrane page of the membrane bag are adhesively bonded to form adhesive lines in the direction of wrapping the center pipe, and the adhesive lines are used to separate flow channels of the auxiliary permeation liquid in the membrane bag. The adhesive lines are spaced apart from each other by connecting notches in the two side positions of the unfolded state of the membrane bag, so that the flow channels are in the form of a plurality of U-shaped spliced wave shapes; the length of the membrane bag wound on the first section of the center pipe corresponds to half of a single U-shaped channel; and the length of the membrane bag wound on the second section of the center pipe corresponds to half of a single U-shaped channel. The size of the notches of the flow channels at the adhesive lines is 5-50 cm. The flow guide net is composed of a plurality of layers of nets with different hole diameters and hole structures, and at least comprises a flow guide upper layer fine net, a flow guide middle layer coarse net and a flow guide lower layer fine net which are arranged in sequence. The hole diameters of the flow guide upper layer fine net and the flow guide lower layer fine net are independently 1-500 microns; and the hole diameter of the flow guide middle layer coarse net is 100-1000 microns. The number of the membrane bags is 1-128; when the number of the membrane bags is greater than or equal to 2, a separation net is arranged between the connected membrane bags. The first membrane page and the second membrane page are independently selected from reverse osmosis membranes, nanofiltration membranes, ultrafiltration membranes, microfiltration membranes, forward osmosis membranes, gas separation membranes or diffusion dialysis membranes; and the thickness of the first membrane page and the second membrane page is independently 10-500 microns. The separation net and the membrane bag are alternately laid, and then are wound on the center pipe together with the membrane bag.

2. A membrane separation process characterized by, The application further relates to an auxiliary permeation coiled membrane assembly. The application further relates to a method for filtering liquid. The application further relates to an auxiliary permeation coiled membrane assembly.

3. A membrane separation device, characterized by, ​

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