A biomimetic guide net based seawater desalination spiral membrane device

Abstract

The application discloses a seawater desalination roll type membrane device based on a biomimetic flow guide net. Multilayer hollow cylindrical reverse osmosis membranes are coaxially arranged in the inside of a reverse osmosis membrane assembly, an annular cavity is formed between every two adjacent reverse osmosis membranes, a hollow cylindrical biomimetic flow guide net is arranged in each annular cavity, the biomimetic flow guide net is coaxially arranged with the reverse osmosis membrane and is located on the central ring line of the annular cavity; liquid to be desalinated is flowed into the reverse osmosis membrane assembly from an inlet, is desalinated by the reverse osmosis membrane and the biomimetic flow guide net, and is finally flowed out of the reverse osmosis membrane assembly from an outlet; a plurality of biomimetic flow guide units of the biomimetic flow guide net are arranged in a longitudinal and transverse staggered mode, and each biomimetic flow guide unit is mainly composed of a plurality of flow guide columns in an elliptical cylindrical structure and is sequentially connected. The application has the advantages of simple structure, high reliability, easy manufacturing and good popularization value, and the structure can further improve the water production efficiency of the roll type membrane assembly and reduce the production cost of a water treatment plant.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of reverse osmosis seawater desalination, and particularly relates to a seawater desalination spiral-wound membrane device based on a biomimetic flow guide net. BACKGROUND

[0002] The spiral-wound membrane module is mainly composed of a thin film composite (TFC) membrane and a flow guide net, and they are wrapped around a perforated central fresh water collection pipe to form a spiral winding structure. The main problem of the spiral-wound membrane module structure is that when the reverse osmosis membrane allows water to pass through, the solute molecules and impurity particles in the process are difficult to diffuse, and will accumulate on the surface of the reverse osmosis membrane to form a concentration boundary layer, also known as the concentration polarization phenomenon, which will exacerbate the energy consumption in the water treatment project. The flow guide net in the membrane module can promote the generation of Karman vortex street, increase the shear rate on the membrane surface, reduce the accumulation of salt and other pollutants, and thus improve the efficiency of water treatment.

[0003] However, most of the flow guide nets on the market reduce the concentration polarization phenomenon on the membrane surface at the expense of increasing energy consumption, and improve the water flux on the membrane surface. The whiskers of seals have a unique undulating surface structure, which can effectively alleviate the vortex shedding when the fluid flows through, thereby reducing the energy dissipation in the fluid flow process. The spiral-wound membrane module with a suitable flow guide net structure can effectively reduce the influence of pollutants on the membrane surface, reduce the energy consumption of seawater desalination, and improve the fresh water separation flux of the reverse osmosis membrane.

[0004] The prior art lacks a biomimetic spiral-wound membrane module structure that can effectively reduce the concentration polarization phenomenon and energy consumption on the surface of the reverse osmosis membrane, and improve the efficiency of permeate water. SUMMARY

[0005] In order to solve the problems in the background art, the present application aims to provide a seawater desalination spiral-wound membrane device based on a biomimetic flow guide net. The present application combines the structure of the whiskers of seals and applies the biomimetic structure to the flow guide net in the spiral-wound membrane module structure, which can effectively reduce the influence of pollutants on the membrane surface, reduce the energy consumption of seawater desalination, and improve the fresh water separation flux of the reverse osmosis membrane.

[0006] The technical solution adopted by the present application is as follows:

[0007] The device comprises a reverse osmosis membrane assembly, a reverse osmosis membrane and a biomimetic flow guide net; a plurality of layers of reverse osmosis membranes are coaxially arranged inside the reverse osmosis membrane assembly, an annular cavity is formed between each adjacent two layers of reverse osmosis membranes, a biomimetic flow guide net is arranged in each annular cavity, the biomimetic flow guide net is coaxially arranged with the reverse osmosis membrane and located on the central ring line of the annular cavity, so that the reverse osmosis membrane and the biomimetic flow guide net are alternately arranged along the radial direction of the reverse osmosis membrane assembly; the liquid to be desalinated flows into the reverse osmosis membrane assembly from the inlet, is desalinated by the reverse osmosis membrane and the biomimetic flow guide net, and finally flows out of the reverse osmosis membrane assembly from the outlet, thereby completing the desalination of the liquid.

[0008] The biomimetic flow guide net is mainly composed of a vertical flow guide wire array and a horizontal flow guide wire array which are connected in layers, the vertical flow guide wire array and the horizontal flow guide wire array are mainly formed by uniformly spacing the biomimetic flow guide wires around the stem along the direction perpendicular to the length of the biomimetic flow guide wires, and the angle θ between the biomimetic flow guide wires in the vertical flow guide wire array and the biomimetic flow guide wires in the horizontal flow guide wire array is 60°-150°.

[0009] The biomimetic flow guide wire is mainly composed of a plurality of biomimetic flow guide units which are connected in sequence along the axial direction of the biomimetic flow guide wire, and the middle part of each biomimetic flow guide unit in the vertical flow guide wire array is in contact with the middle part of each biomimetic flow guide unit in the horizontal flow guide wire array.

[0010] The biomimetic flow guide unit is mainly composed of four columnar structure flow guide columns which are connected in sequence along the axial direction of the biomimetic flow guide unit, the two end faces of the flow guide column are inclined planes in the shape of an ellipse, the sizes of the two end faces of the flow guide column are different, the end face with a smaller long axis of the flow guide column is the first elliptical face, the end face with a larger long axis of the flow guide column is the second elliptical face, the two end faces of the flow guide column are connected by an arc-shaped curved side face, the four connected flow guide columns are sequentially a first flow guide column, a second flow guide column, a third flow guide column and a fourth flow guide column from top to bottom, the first elliptical face and the second elliptical face of the second flow guide column are connected with the first elliptical face of the first flow guide column and the second elliptical face of the third flow guide column respectively, and the first elliptical face of the third flow guide column is connected with the first elliptical face of the fourth flow guide column.

[0011] The first flow guide column and the fourth flow guide column in the biomimetic flow guide unit are connected with two adjacent biomimetic flow guide units on the same biomimetic flow guide wire respectively.

[0012] The length of the short axis l of the first elliptical face is 0.18mm-0.25mm, the length of the long axis k of the first elliptical face is 0.30mm-0.41mm, the length of the short axis t of the second elliptical face is 0.16mm-0.21mm, the length of the long axis s of the second elliptical face is 0.42mm-0.51mm, the ratio of the short axis of the first elliptical face to the short axis of the second elliptical face is greater than or equal to 1.10, and the ratio of the long axis of the second elliptical face to the long axis of the first elliptical face is greater than or equal to 1.07.

[0013] The area ratio of the first and second ellipsoidal surfaces ranges from 0.70 to 1.84.

[0014] In the biomimetic flow guide unit, the direction parallel to the central axis of the biomimetic flow guide unit is defined as the z-axis, and the plane perpendicular to the z-axis is defined as the xy plane direction; the angle between the first ellipsoidal surface in the biomimetic flow guide unit and the xy plane is 16.6°-18.6°, and the angle between the second ellipsoidal surface in the biomimetic flow guide unit and the xy plane is 14.27°-16.27°.

[0015] The reverse osmosis membrane assembly comprises end covers, a ring-shaped outer shell and a central fresh water collection pipe, two end covers are arranged at two ends of the outer shell respectively, a fresh water outlet is formed in the middle of the end cover, a plurality of concentrated water inlets are formed in the outer periphery of the end cover, the central fresh water collection pipe is coaxially arranged in the middle of the outer shell, the outlet of the central fresh water collection pipe is communicated with the fresh water outlet, the reverse osmosis membrane and the biomimetic flow guide net are arranged outside the central fresh water collection pipe, the liquid to be desalinated flows into the reverse osmosis membrane assembly from the concentrated water inlets, is desalinated by the reverse osmosis membrane and the biomimetic flow guide net, and then flows into the central fresh water collection pipe and finally flows out from the fresh water outlet of the reverse osmosis membrane assembly.

[0016] In the same flow guide column, the distance M between the first ellipsoidal surface and the second ellipsoidal surface along the z-axis direction is 0.70mm-1.54mm.

[0017] The thickness H of the biomimetic flow guide net ranges from 0.5mm to 0.8mm.

[0018] The horizontal distance D between every two adjacent biomimetic flow guide wires in the vertical flow guide wire array / horizontal flow guide wire array ranges from 3mm to 6mm.

[0019] The roll type membrane device mainly surrounds the biomimetic flow guide net of seal whiskers. The flow guide net in the roll type membrane device can mainly support, protect and separate the reverse osmosis membrane of the roll type membrane device, and can also enhance the mass transfer capacity of the roll type membrane device to a certain extent and reduce the concentration accumulation and scaling on the surface of the permeation membrane. The biomimetic flow guide net has a unique undulating wave surface structure, can effectively relieve vortex shedding when fluid flows through, and reduce energy dissipation in the fluid flow process, and is an ideal flow guide net structure which can reduce energy consumption and improve the water production capacity of the roll type membrane device.

[0020] The beneficial effects of the present application are as follows:

[0021] 1. The biomimetic flow guide net in the present application is composed of a plurality of biomimetic flow guide units arranged periodically, and such repetitive structure is beneficial to processing and manufacturing, low in cost, good in popularization value, and can ensure small deformation amount during use and prolong service life.

[0022] 2、The roll type membrane device using the bionic guide net provided by the application can be applied to the fields of seawater desalination and industrial wastewater treatment, and has the advantages of simple structure, high reliability, easy manufacturing and good popularization value. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural composition schematic diagram of the roll type membrane device;

[0024] Figure 2 is a three-view diagram of the bionic guide net;

[0025] Figure 3 is a structural unit diagram of the bionic guide net;

[0026] Figure 4 is a comparison diagram of water production of the roll type membrane assembly structure using the bionic guide net and the roll type membrane assembly structure using the traditional commercial guide net under different Reynolds numbers;

[0027] Figure 5 is a comparison diagram of pressure loss of the roll type membrane assembly structure using the bionic guide net and the roll type membrane assembly structure using the traditional commercial guide net under different Reynolds numbers.

[0028] In the figure: 1 is a fresh water outlet; 2 is a concentrated water inlet; 3 is an end cover; 4 is an outer shell; 5 is a central fresh water collection pipe; 6 is a reverse osmosis membrane; 7 is a bionic guide net; 8 is a bionic guide unit; 9 is a first elliptical surface; and 10 is a second elliptical surface. DETAILED DESCRIPTION

[0029] The application will be described in detail below in combination with specific implementation cases, and the following implementation cases will help the person skilled in the art to further understand the application, but do not limit the application in any form.

[0030] As Figure 1As shown, the device comprises a reverse osmosis membrane assembly, a reverse osmosis membrane 6 and a biomimetic flow guide net 7; a plurality of hollow cylindrical reverse osmosis membranes 6 are coaxially arranged inside the reverse osmosis membrane assembly, an annular cavity is formed between each adjacent two layers of reverse osmosis membranes 6, at least one layer of hollow cylindrical biomimetic flow guide net 7 is arranged in each annular cavity, the biomimetic flow guide net 7 is coaxially arranged with the reverse osmosis membrane 6 and located on the central ring line of the annular cavity, so that the reverse osmosis membrane 6 and the biomimetic flow guide net 7 are alternately arranged along the radial direction of the reverse osmosis membrane assembly, and at least one layer of biomimetic flow guide net 7 is arranged between each adjacent two layers of reverse osmosis membranes 6; the liquid to be desalinated flows into the reverse osmosis membrane assembly from the inlet, is desalinated by the reverse osmosis membrane 6 and the biomimetic flow guide net 7, and finally flows out of the reverse osmosis membrane assembly from the outlet, thereby completing the desalination of the liquid.

[0031] As shown in Figure 2 , the biomimetic flow guide net 7 is mainly composed of a layer of vertical flow guide wire array and a layer of horizontal flow guide wire array connected in layers, the vertical flow guide wire array and the horizontal flow guide wire array are mainly formed by evenly and uniformly spacing the biomimetic flow guide wires around the stem along the horizontal direction perpendicular to the length of the biomimetic flow guide wires, the angle θ between the biomimetic flow guide wires in the vertical flow guide wire array and the biomimetic flow guide wires in the horizontal flow guide wire array is 60°-150°, and the biomimetic flow guide wires in the vertical flow guide wire array and the biomimetic flow guide wires in the horizontal flow guide wire array are arranged in a grid structure in a vertical and horizontal interlaced manner;

[0032] The biomimetic flow guide wire is mainly formed by sequentially connecting a plurality of biomimetic flow guide units 8 along the axial direction of the biomimetic flow guide unit 8, and the middle part of each biomimetic flow guide unit 8 in the vertical flow guide wire array is in contact with the middle part of each biomimetic flow guide unit 8 in the horizontal flow guide wire array.

[0033] As shown in Figure 3 , the biomimetic flow guide unit 8 is mainly composed of four columnar flow guide columns connected in sequence along the axial direction of the flow guide column, both ends of the flow guide column are inclined planes in the shape of an ellipse, and the sizes of the two ends of the flow guide column are different, the end with a smaller major axis of the flow guide column is taken as the first elliptical surface 9, and the end with a larger major axis of the flow guide column is taken as the second elliptical surface 10, the two ends of the flow guide column are connected by an arc-shaped curved side surface, the four connected flow guide columns are sequentially the first flow guide column, the second flow guide column, the third flow guide column and the fourth flow guide column from top to bottom, the first elliptical surface 9 and the second elliptical surface 10 of the second flow guide column are connected with the first elliptical surface 9 of the first flow guide column and the second elliptical surface 10 of the third flow guide column respectively, the first elliptical surface 9 of the third flow guide column is connected with the first elliptical surface 9 of the fourth flow guide column, and specifically, the second flow guide column and the third flow guide column are symmetrically arranged with the center of gravity of the biomimetic flow guide unit 8; the first flow guide column and the fourth flow guide column are symmetrically arranged with the center of gravity of the biomimetic flow guide unit 8;

[0034] The first guide column and the fourth guide column in the bionic guide unit 8 are connected with two adjacent bionic guide units on the same bionic guide wire respectively.

[0035] The length of the short axis l of the first elliptical surface 9 ranges from 0.18mm to 0.25mm, and the length of the long axis k ranges from 0.30mm to 0.41mm; the length of the short axis t of the second elliptical surface 10 ranges from 0.16mm to 0.21mm, and the length of the long axis s ranges from 0.42mm to 0.51mm; the ratio of the short axis of the first elliptical surface 9 to the short axis of the second elliptical surface 10 is greater than or equal to 1.10, and the ratio of the long axis of the second elliptical surface 10 to the long axis of the first elliptical surface 9 is greater than or equal to 1.07, so that the bionic guide unit 8 has better bionic effect without deviating from the original structure of the seal whisker.

[0036] The area ratio of the first elliptical surface 9 to the second elliptical surface 10 ranges from 0.70 to 1.84, and a larger area ratio can further alleviate the shedding of vortex in flow, reduce the pressure loss of the spiral membrane module using the bionic guide net, but the water production will also decrease significantly. The optimal area ratio of the first elliptical surface 9 to the second elliptical surface 10 is 1.254.

[0037] In the bionic guide unit 8, the direction parallel to the central axis of the bionic guide unit 8 is defined as the z axis, and the plane perpendicular to the z axis is defined as the xy plane direction; the angle β between the first elliptical surface 9 in the bionic guide unit 8 and the xy plane is 16.6°-18.6°, and the angle α between the second elliptical surface 10 in the bionic guide unit 8 and the xy plane is 14.27°-16.27°, the angle ensures the integrity of the bionic structure, and at the same time can further disturb the concentration layer on the surface of the reverse osmosis membrane 6, improve the water production efficiency of the spiral membrane module using the bionic guide net, and reduce the water treatment cost.

[0038] The reverse osmosis membrane module comprises an end cover 3, an annular outer shell 4 and a central fresh water collecting pipe 5, two end covers 3 are arranged at two ends of the outer shell 4 respectively, a fresh water outlet 1 is formed in the middle of the end cover 3, a circle of concentrated water inlets 2 is formed in the outer periphery of the end cover 3, the central fresh water collecting pipe 5 is coaxially arranged in the middle of the outer shell 4, the outlet of the central fresh water collecting pipe 5 is communicated with the fresh water outlet 1, the reverse osmosis membrane 6 and the bionic guide net 7 are sleeved outside the central fresh water collecting pipe 5, the liquid to be desalinated flows into the reverse osmosis membrane module from the concentrated water inlets 2, is desalinated by the reverse osmosis membrane 6 and the bionic guide net 7, and then flows into the central fresh water collecting pipe 5, and finally flows out from the fresh water outlet 1 of the reverse osmosis membrane module.

[0039] Specifically, the reverse osmosis membrane 6 and the bionic guide net 7 are wrapped and wound on the central fresh water collecting pipe 5 with holes, and then the outer shell 4 is sleeved on the outermost layer, and the end covers 3 are arranged at two ends of the outer shell 4.

[0040] In the same guide column, the distance M between the first elliptical surface 9 and the second elliptical surface 10 along the z-axis direction is 0.70mm-1.54mm, so that the water production efficiency of the spiral-wound membrane module using the bionic guide net can be maximized while ensuring the integrity of the bionic structure.

[0041] The thickness H of the bionic guide net 7 is 0.5mm-0.8mm.

[0042] The horizontal distance D between every two adjacent bionic guide wires in the vertical guide wire array / horizontal guide wire array is 3mm-6mm.

[0043] The specific implementation of the present application is as follows:

[0044] When the device is used, the concentrated water enters the concentrated water inlet 2, passes through the layer-by-layer reverse osmosis membrane 6 and the bionic guide net 7, and then enters the central fresh water collection pipe 5. At this time, the water in the central fresh water collection pipe 5 has been filtered and is fresh water. The fresh water flows out from the fresh water outlet 1 at one end of the central fresh water collection pipe 5.

[0045] In the embodiment, as shown in Figure 2 and Figure 3 The bionic guide net 7 is composed of a plurality of bionic guide units 8 arranged periodically. This repetitive structure is beneficial to processing and manufacturing, has low cost, has good popularization value, and can ensure a small deformation amount during use. The bionic guide units 8 are sequentially connected in two directions to form bionic guide wires. The angle θ formed by the bionic guide wires is 60°-150°, and the optimal angle θ is 90°. In this way, the spiral-wound membrane module device has a higher water production flux.

[0046] The bionic guide wires in the two directions composed of the bionic guide units 8 are in a stacked state. The stacking height H is 0.5mm-0.8mm, and the optimal stacking height H is 0.8mm. A higher stacking height helps to further enhance the disturbance of the concentrated water during the flow process and reduce the influence of the concentration polarization phenomenon.

[0047] The distance D between the bionic guide wires in the parallel direction composed of the bionic guide units 8 is 3mm-6mm, and the optimal distance D between the bionic guide wires is 4.5mm. Too small a distance will cause too large a pressure loss and increase the energy consumption in the water treatment process. Too large a distance will cause insufficient mixing of the concentration layer on the membrane surface and cause a larger concentration polarization phenomenon, which affects the water production efficiency.

[0048] The shape of the biomimetic flow guiding unit 8 is mainly controlled by the first and second elliptical surfaces 9 and 10 with different long and short diameters, and the configuration of a complete biomimetic flow guiding unit 8 should be controlled in sequence along the z direction, i.e., the second elliptical surface 10, the first elliptical surface 9, the second elliptical surface 10, the first elliptical surface 9, and the second elliptical surface 10.

[0049] As shown in Figure 4 and Figure 5 Through numerical simulation calculation, the water production flux and pressure loss of the biomimetic flow guiding net are obtained, and the control variables of the optimal embodiment are as follows: the angle θ formed by the biomimetic flow guiding wire is 90°; the stacking height H of the biomimetic flow guiding unit 8 is 0.8 mm; the spacing D between the biomimetic flow guiding wires is 4.5 mm; the area ratio of the first elliptical surface (9) to the second elliptical surface (10) is 1.254; under different Reynolds numbers, the spiral membrane device of the present application has higher water production flux and lower pressure loss than the traditional cylindrical flow guiding net, and the effect of the optimal embodiment is the best, which indicates that the device can effectively reduce the influence of membrane surface pollutants, reduce the energy consumption of seawater desalination, and improve the fresh water separation flux of the reverse osmosis membrane.

Claims

1. A seawater desalination spiral wound membrane device based on a biomimetic flow guide net, characterized in that: The system includes a reverse osmosis membrane module, a reverse osmosis membrane (6), and a biomimetic flow guide net (7). Several layers of reverse osmosis membranes (6) are coaxially arranged inside the reverse osmosis membrane module. An annular cavity is formed between each two adjacent reverse osmosis membranes (6). A biomimetic flow guide net (7) is provided in each annular cavity. The biomimetic flow guide net (7) is coaxially arranged with the reverse osmosis membrane (6) and located on the central ring line of the annular cavity, so that the reverse osmosis membrane (6) and the biomimetic flow guide net (7) are arranged alternately along the radial direction of the reverse osmosis membrane module. The liquid to be desalinated flows in from the inlet of the reverse osmosis membrane module, is desalinated by the reverse osmosis membrane (6) and the biomimetic flow guide net (7), and finally flows out from the outlet of the reverse osmosis membrane module, thus completing the desalination process. The bionic flow guiding net (7) is mainly composed of a layer of vertical flow guiding wire array and a layer of horizontal flow guiding wire array stacked together. The vertical flow guiding wire array and the horizontal flow guiding wire array are mainly formed by the bionic flow guiding wires around the root evenly spaced along the length direction perpendicular to themselves. The angle θ between the bionic flow guiding wires in the vertical flow guiding wire array and the bionic flow guiding wires in the horizontal flow guiding wire array is 60°~150°. The bionic guide wire is mainly formed by connecting several bionic guide units (8) sequentially along its own axis. The middle part of each bionic guide unit (8) in the vertical guide wire array and the middle part of each bionic guide unit (8) in the horizontal guide wire array are in contact with each other. The biomimetic flow guiding unit (8) is mainly composed of four columnar flow guiding columns connected sequentially along its own axis. The two end faces of the flow guiding column are elliptical inclined planes, and the two end faces of the flow guiding column are not the same size. The end face with the smaller major axis of the flow guiding column is the first elliptical surface (9), and the end face with the larger major axis of the flow guiding column is the second elliptical surface (10). The two end faces of the flow guiding column are connected by the curved side of the arc. The four connected flow guiding columns are the first flow guiding column, the second flow guiding column, the third flow guiding column and the fourth flow guiding column from top to bottom. The first elliptical surface (9) and the second elliptical surface (10) of the second flow guiding column are connected to the first elliptical surface (9) of the first flow guiding column and the second elliptical surface (10) of the third flow guiding column, respectively. The first elliptical surface (9) of the third flow guiding column is connected to the first elliptical surface (9) of the fourth flow guiding column. The first and fourth guide columns in the bionic guide unit (8) are respectively connected to two adjacent bionic guide units (8) on the same bionic guide wire.

2. The seawater desalination spiral membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: The minor axis of the first elliptical surface (9) l The length ranges from 0.18mm to 0.25mm, with the major axis... k The length ranges from 0.30 mm to 0.41 mm, and the minor axis of the second elliptical surface (10) t The length ranges from 0.16mm to 0.21mm, with the major axis... s The length ranges from 0.42mm to 0.51mm, and the ratio of the minor axis of the first elliptical surface (9) to the minor axis of the second elliptical surface (10) is greater than or equal to 1.10, and the ratio of the major axis of the second elliptical surface (10) to the major axis of the first elliptical surface (9) is greater than or equal to 1.

07.

3. The seawater desalination spiral membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: The area ratio of the first elliptical surface (9) to the second elliptical surface (10) ranges from 0.70 to 1.

84.

4. The seawater desalination spiral membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: In the biomimetic flow guiding unit (8), the direction parallel to the central axis of the biomimetic flow guiding unit (8) is defined as the z-axis, and the plane perpendicular to the z-axis is defined as the xy-plane direction; the angle β between the first elliptical surface (9) in the biomimetic flow guiding unit (8) and the xy-plane is 16.6°~18.6°, and the angle α between the second elliptical surface (10) in the biomimetic flow guiding unit (8) and the xy-plane is 14.27°~16.27°.

5. A seawater desalination spiral wound membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: The reverse osmosis membrane module includes end caps (3), an annular shell (4), and a central freshwater collection pipe (5). Two end caps (3) are respectively provided at both ends of the shell (4). A freshwater outlet (1) is opened in the middle of the end cap (3), and a concentrated water inlet (2) is opened around the outer periphery of the end cap (3). The central freshwater collection pipe (5) is coaxially arranged in the middle of the shell (4). The outlet of the central freshwater collection pipe (5) is connected to the freshwater outlet (1). The reverse osmosis membrane (6) and the biomimetic guide net (7) are both sleeved on the outside of the central freshwater collection pipe (5). The liquid to be desalinated flows in from the concentrated water inlet (2) of the reverse osmosis membrane module, and after being desalinated by the reverse osmosis membrane (6) and the biomimetic guide net (7), it flows into the central freshwater collection pipe (5) and finally flows out from the freshwater outlet (1) of the reverse osmosis membrane module.

6. A seawater desalination spiral membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: In the same guide column, the distance M between the first elliptical surface (9) and the second elliptical surface (10) along the z-axis is 0.70 mm ~ 1.54 mm.

7. A seawater desalination spiral wound membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: The thickness H of the biomimetic flow guide net (7) ranges from 0.5 mm to 0.8 mm.

8. A seawater desalination spiral wound membrane device based on a biomimetic flow guide net according to claim 1, characterized in that: The horizontal spacing D between each pair of adjacent biomimetic guide wires in the vertical guide wire array / horizontal guide wire array is 3mm~6mm.

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