Anti-scaling elastic separation net for nanofiltration membrane

Abstract

The utility model relates to an anti-scaling elastic separation net of a nanofiltration membrane, which comprises a separation net body, the separation net body is formed by weaving a plurality of longitudinal net wires arranged at equal intervals and a plurality of transverse net wires arranged at equal intervals, and the longitudinal net wires and the transverse net wires are all made of flexible high polymer materials. The utility model relates to the technical field of nanofiltration membranes. According to the anti-scaling elastic separation net for the nanofiltration membrane, the separation net body formed by weaving the longitudinal net wires and the transverse net wires is arranged, and the longitudinal net wires and the transverse net wires are made of flexible high polymer materials, so that the separation net body has flexibility, and when high-salt water flows through the separation net body under the pushing of high pressure, the separation net body is not prone to scaling; the separation net body is deformed under high-speed disturbance of fluid, so that salt crystals attached to the separation net body fall off, the blockage of meshes caused by accumulation of the salt crystals is avoided, and the influence on the filtering efficiency of the nanofiltration membrane due to the influence on the flow rate of water flow is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of nanofiltration membranes, in particular to an anti-scaling elastic spacer for a nanofiltration membrane. Background Art

[0002] The spiral wound membrane element is the main membrane form of commercial nanofiltration membrane elements, which has the advantages of simple structure and low cost. The concentrated water spacer between the membrane sheets in the nanofiltration membrane is the core component affecting the performance of the membrane element, and has a direct impact on the mass transfer of fluid in the flow channel. On the one hand, the concentrated water spacer can prevent the membrane sheets from fitting together under high pressure and provide a flow channel for the inlet water; on the other hand, it can increase the turbulence degree on the membrane surface, reduce the concentration polarization and fouling deposition on the membrane surface, and at the same time ensure the uniform distribution of the inlet water on the membrane surface.

[0003] In the prior art, when highly concentrating seawater, salt ions such as calcium and magnesium ions or other impurities in the high-salt water will deposit and scale on the surface of the concentrated water spacer, pollute the membrane, reduce the permeation flux and water production quality of the membrane, increase the operating pressure, shorten the service life of the membrane, and cause an increase in cost and waste of energy. Summary of the Utility Model

[0004] Aiming at the deficiencies existing in the prior art, the purpose of the utility model is to provide an anti-scaling elastic spacer for a nanofiltration membrane, so as to solve the technical problems mentioned in the above background art.

[0005] The above technical purpose of the utility model is achieved through the following technical solutions:

[0006] An anti-scaling elastic spacer for a nanofiltration membrane, including a spacer body, which is woven from a plurality of longitudinally arranged wires spaced at equal intervals and a plurality of transversely arranged wires spaced at equal intervals. Both the longitudinally arranged wires and the transversely arranged wires are made of flexible polymer materials.

[0007] Furthermore, a rhombic mesh is formed between adjacent pairs of the longitudinally arranged wires and the transversely arranged wires.

[0008] Furthermore, the included angle of the rhombic mesh is 75 degrees.

[0009] Furthermore, a support portion for supporting the membrane is formed by protruding at the intersection nodes of the longitudinally arranged wires and the transversely arranged wires.

[0010] Furthermore, the protruding heights of the support portions are the same, and an arc surface for fitting and contacting the membrane is provided at the top of the support portions.

[0011] To sum up, the utility model includes at least the following beneficial technical effects:

[0012] 1. The anti-scaling elastic spacer for nanofiltration membrane is composed of a spacer body woven with longitudinal filaments and transverse filaments. The longitudinal filaments and transverse filaments are made of flexible polymer materials, which endows the spacer body with flexibility. When high-salinity water flows through the spacer body under high pressure, the spacer body deforms under the high-speed fluid disturbance, causing the salt crystals attached to the spacer body to fall off, thus avoiding the blockage of mesh holes caused by the accumulation of salt crystals and preventing the influence on the water flow rate and the filtration efficiency of the nanofiltration membrane.

[0013] 2. The anti-scaling elastic spacer for nanofiltration membrane is provided with diamond-shaped mesh holes with an included angle of 75 degrees, which can maintain the best turbulence effect while reducing pressure loss, effectively improving the filtration effect of the nanofiltration membrane.

[0014] 3. The anti-scaling elastic spacer for nanofiltration membrane is provided with a support part, which increases the gap for high-salinity water to pass between the membrane and the spacer body, ensuring uniform water flow distribution. The protruding design can also improve the water flow distribution on the membrane surface, ensuring uniform inlet water distribution, avoiding local high flow velocity or dead zones, and enhancing the pressure resistance and separation performance of the entire membrane sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] Figure 1 FIG. 1 is a schematic structural diagram of the anti-scaling elastic spacer for nanofiltration membrane of the present invention.

[0017] Figure 2 FIG. 2 is a schematic structural diagram of the anti-scaling elastic spacer for nanofiltration membrane of the present invention wound around a collecting pipe.

[0018] Figure 3 FIG. 3 is a schematic diagram of the flexibility of the anti-scaling elastic spacer for nanofiltration membrane of the present invention.

[0019] Figure 4 FIG. 4 is a schematic structural diagram of the diamond-shaped mesh holes in the anti-scaling elastic spacer for nanofiltration membrane of the present invention.

[0020] Figure 5 FIG. 5 is a schematic structural diagram of the support part in the anti-scaling elastic spacer for nanofiltration membrane of the present invention.

[0021] In the figures, 1, longitudinal filament; 2, transverse filament; 3, diamond-shaped mesh hole; 4, support part. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following further describes the present utility model in detail with reference to the accompanying drawings.

[0023] Embodiment:

[0024] Refer to Figure 1 - Figure 5 A scale-resistant elastic spacer net for a nanofiltration membrane disclosed by the present utility model includes a spacer net body, which is woven by a plurality of longitudinally arranged wire meshes 1 spaced at equal intervals and a plurality of transversely arranged wire meshes 2 spaced at equal intervals. Both the longitudinally arranged wire meshes 1 and the transversely arranged wire meshes 2 are made of flexible polymer materials.

[0025] In this embodiment, a spiral wound membrane module is usually wound around a central porous collecting pipe by a membrane sheet, a concentrated water spacer net, and a permeate water spacer net. In order to increase stability, a relatively hard rigid material is usually used to prepare the spacer net for the nanofiltration membrane, and the spacer net is used to provide support for the membrane to meet the spatial stability.

[0026] Since the spacer net made of a hard material has a hard contact with the membrane, it will apply pressure to the surface of the membrane, resulting in compressive stress on the surface of the membrane, which is likely to damage the membrane and reduce the service life of the nanofiltration membrane. In addition, the scale deposited in the mesh of the rigid spacer net is not easily disturbed by the water flow, so that the scale is directly washed off by the water flow, resulting in a reduction in the mesh of the spacer net and affecting the water flow rate, thereby reducing the filtration efficiency of the nanofiltration membrane.

[0027] Therefore, it can be observed Figure 1 and Figure 3 that by making the longitudinally arranged wire meshes 1 and the transversely arranged wire meshes 2 that are woven into the spacer net body made of flexible polymer materials, when the water flow passes through the spacer net body under the push of pressure, the spacer net body deforms under the high-speed disturbance of the fluid, so that the salt crystals attached to the spacer net body fall off, thereby avoiding the blockage of the mesh caused by the accumulation of salt crystals and preventing the influence on the water flow rate and the filtration efficiency of the nanofiltration membrane.

[0028] The above-mentioned flexible polymer material can be made of materials such as polyethylene polymer materials and polypropylene polymer materials, which have the characteristics of good chemical stability, low rigidity, and small water absorption.

[0029] In a further preferred embodiment of the present utility model, as Figure 1 shown, a diamond-shaped mesh 3 is formed between two adjacent pairs of the longitudinally arranged wire meshes 1 and the transversely arranged wire meshes 2.

[0030] In this embodiment, when filtering high-salt water, the high-salt water will be pressed into the nanofiltration membrane under the action of pressure, resulting in a concentration polarization phenomenon in which the solute in the high-salt water is intercepted by the membrane. Therefore, it can be observed Figure 1It can be found that the longitudinal filaments 1 and transverse filaments 2 forming the spacer mesh body are cross-woven, and a diamond-shaped mesh opening 3 is formed between two adjacent pairs of longitudinal filaments 1 and transverse filaments 2, causing turbulence when water flows through the spacer mesh body, thereby enhancing the disturbance of the water flow, reducing the concentration polarization phenomenon, and effectively improving the filtration performance of the nanofiltration membrane.

[0031] In a further preferred embodiment of the present invention, as Figure 4 shown, the included angle of the diamond-shaped mesh opening 3 is 75 degrees.

[0032] In this embodiment, since the high-salt water will come into contact with the spacer mesh and be blocked by it to generate turbulence when flowing under pressure, the contact angle between the spacer mesh and the flowing direction of the high-salt water is the key to affecting the turbulence effect.

[0033] When the included angle of the longitudinal filament 1 or the transverse filament 2 is 90 degrees, the flowing direction of the high-salt water is perpendicular to the longitudinal filament 1 or the transverse filament 2, seriously interfering with the flow of the high-salt water. At this time, the best turbulence effect is generated, but the high-salt water will also lose a large amount of pressure due to being blocked, affecting the subsequent filtration efficiency of the high-salt water; when the included angle of the longitudinal filament 1 or the transverse filament 2 is less than 90 degrees, the blocking effect of the longitudinal filament 1 and the transverse filament 2 on the forward movement of the high-salt water becomes worse, which will affect the turbulence effect to a certain extent. Therefore, in order to make the neutralization effect of the spacer mesh body better, the included angle of the diamond-shaped mesh opening 3 is less than 90 degrees. As the angle decreases, the lost pressure will gradually decrease, but the turbulence effect will also gradually become worse.

[0034] Therefore, as Figure 4 shown at A in, making the included angle of the diamond-shaped mesh opening 3 be 75 degrees can keep the turbulence effect optimal while reducing the pressure loss, effectively improving the filtration effect of the nanofiltration membrane.

[0035] In a further preferred embodiment of the present invention, as Figures 1 - 5 shown, a support portion 4 for supporting the membrane is formed by convexity at the cross-node of the longitudinal filament 1 and the transverse filament 2.

[0036] In this embodiment, since the spacer mesh body is arranged between the collecting pipe and the membrane to provide support for the membrane, when the membrane is attached to the spacer mesh body, the clearance surface through which the high-salt water can pass will become very small, seriously affecting the filtration efficiency of the nanofiltration membrane.

[0037] Therefore, observing Figure 1 it can be found that a support portion 4 for supporting the membrane is arranged at the cross-node of the longitudinal filament 1 and the transverse filament 2, so that when the membrane contacts the spacer mesh body, as Figure 5The shown part is propped up, increasing the gap for the high-salt water to pass between the membrane and the spacer body, thereby ensuring uniform water flow distribution. The protruding design can also improve the water flow distribution on the membrane surface, ensuring uniform inlet water distribution, avoiding local high flow velocity or dead zones, and enhancing the compression resistance and separation performance of the entire membrane sheet.

[0038] Meanwhile, the setting of the supporting part 4 will also cause obstruction when the high-salt water flows, promoting the fluid to form a more complex flow path, thereby effectively increasing the shear force and disturbance of the water flow, reducing the generation of dirt, and improving the membrane cleaning effect and service life.

[0039] In a further preferred embodiment of the present utility model, as Figure 5 shown, the protruding heights of the supporting parts 4 are the same, and an arc surface in contact with the membrane is provided at the top of the supporting part 4.

[0040] In this embodiment, since the side surface of the original spacer body is in contact with the membrane as a whole, the contact area is large. After adding the supporting part 4, the contact area between the membrane and the spacer body will decrease, and the contact method changes from surface contact to matrix-type point contact. When the membrane is under pressure, the compressive stress at the contact points will increase sharply, resulting in membrane damage and affecting the subsequent use of the nanofiltration membrane.

[0041] Therefore, it can be observed that Figure 5 keeping the protruding heights of each supporting part 4 the same and providing an arc surface at the top of the supporting part 4 can increase the contact area of the membrane when it contacts the supporting part 4, thereby reducing the stress concentration to a certain extent and improving the compression resistance of the membrane.

[0042] Meanwhile, the setting of the arc surface can prevent the membrane from being pressed against sharp parts such as corners and edges when it contacts the supporting part 4, further avoiding local compressive stress concentration and accelerating the damage of the membrane when the membrane contacts the supporting part 4, thereby further enhancing the service life of the nanofiltration membrane.

[0043] The embodiments of this specific implementation manner are all preferred embodiments of the present utility model, and do not limit the protection scope of the present utility model accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present utility model should be covered within the protection scope of the present utility model.

Claims

1. A fouling-resistant elastic spacer for a nanofiltration membrane, characterized in that, It includes a net body, which is woven by a number of longitudinally arranged wires (1) spaced at equal intervals and a number of transversely arranged wires (2) spaced at equal intervals. Both the longitudinally arranged wires (1) and the transversely arranged wires (2) are made of flexible polymer materials.

2. The anti-scaling elastic spacer grid for a nanofiltration membrane according to claim 1, wherein A diamond-shaped mesh (3) is formed between two adjacent pairs of the longitudinally arranged wires (1) and the transversely arranged wires (2).

3. A kind of anti-scaling elastic spacer for nanofiltration membrane according to claim 2, characterized in that, The included angle of the diamond-shaped mesh (3) is 75 degrees.

4. A fouling-resistant elastic spacer for a nanofiltration membrane according to claim 1, characterized in that, At the cross nodes of the longitudinally arranged wires (1) and the transversely arranged wires (2), there are formed supporting parts (4) for supporting the film.

5. A fouling-resistant elastic spacer for a nanofiltration membrane according to claim 4, characterized in that, The protruding heights of the supporting parts (4) are the same, and the top of the supporting parts (4) is provided with an arc surface that is in fitting contact with the film.

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