Method, storage medium and device for increasing effective membrane area of ​​spiral wound membrane element

Abstract

The present invention relates to the technical field of spiral-wound membrane elements, and more specifically, to a method, storage medium, and device for increasing the effective membrane area of ​​a spiral-wound membrane element. The method comprises determining the Archimedean spiral expression r1 for the upper page and r1′ for the lower page of each folded membrane sheet; determining the arc length expression L1 corresponding to r1 and the arc length expression L1′ corresponding to r1′; determining the offset value L0 between the upper and lower pages of each folded membrane sheet based on the difference between L1 and L1′; and determining the offset value ΔL between each two adjacent folded membrane sheets at the folded end. The storage medium stores computer program instructions; the device comprises at least one processor, at least one memory, and the computer program instructions stored in the memory, and the method is implemented when the computer program instructions are executed by the processor. The present invention can ensure that the membrane is fully and effectively utilized.

Description

Technical Field

[0001] The present invention relates to the technical field of spiral-wound membrane elements, and in particular to a method, a storage medium and a device for increasing the effective membrane area of ​​a spiral-wound membrane element. Background Art

[0002] Membrane technology is widely used due to its simplicity, high packing density, high water quality, ease of automated operation, and convenient maintenance. Currently, the membrane elements used in filtration devices primarily include spiral-wound membrane elements, hollow fiber membrane elements, tubular membrane elements, and plate-and-frame membrane elements. Spiral-wound membrane elements have a significant market share due to their compact design and low price.

[0003] Spiral-wound membrane elements are primarily composed of membrane sheets, feed manifolds, permeate manifolds, and a collection pipe, all rolled together in a specific sequence. Multiple layers of permeate manifolds are first wound around the outside of the collection pipe, forming the innermost layer of permeate manifolds. Subsequently, folded membrane sheets and permeate manifolds are stacked on the outside of the innermost permeate manifold, first on top of the folded membrane sheet, then on top of the permeate manifolds. This sequence continues until the outermost folded membrane sheet is reached, eliminating the need for additional permeate manifolds. The entire element is then rolled onto the collection pipe, forming a spiral-wound membrane element. The manufacturing process for the folded membrane is as follows: a membrane sheet of a certain size is folded, dividing it into two parts: the upper diaphragm sheet is called the upper leaf, and the lower diaphragm sheet is called the lower leaf. A sheet of feed manifolds is sandwiched between the upper and lower leaves to form the folded membrane sheet. In addition, the folded end of the diaphragm (i.e., the closed end) is connected to the water collecting pipe along the axial direction of the water collecting pipe, and the two adjacent folded diaphragms and the water production flow channel cloth between the two are sealed at the boundary with sealing glue to form a membrane bag for collecting the produced water. The sealing glue is sealed in an open shape, that is, there is no sealing glue at the closed end of the diaphragm, and the other three sides (i.e., the three non-closed ends of the diaphragm) are sealed with sealing glue; the fluid enters the folded diaphragm from the feed flow channel cloth along the axial direction of the water collecting pipe, and through the action of pressure and the separation characteristics of the diaphragm itself, the fluid is separated by the diaphragm to form a relatively clean fluid and a relatively dirty fluid; among them, the relatively clean fluid is collected in the water collection channel to form produced water along the water production flow channel cloth perpendicular to the axial direction of the water collecting pipe; the relatively dirty fluid continues to flow out of the membrane element from the feed flow channel cloth along the axial direction of the water collecting pipe.

[0004] However, during the membrane folding process before rolling, the focus is often on leaving enough space at the bottom edge of the membrane to allow for adequate adhesion to the water production channel fabric and sealant, while overlooking the issue of underutilization. Folding the membrane directly in half or folding it inappropriately with an offset fold will result in underutilization, reducing the effective water treatment area and, in turn, lowering the water production efficiency of the membrane element.

[0005] In summary, a method, storage medium and device for increasing the effective membrane area of ​​a spiral-wound membrane element are needed to solve the problem of insufficient utilization of the membrane in the prior art. Summary of the Invention

[0006] The present invention aims to provide a method, storage medium and device for increasing the effective membrane area of ​​a spiral-wound membrane element. The specific technical solution is as follows:

[0007] In a first aspect, the present invention provides a method for increasing the effective membrane area of ​​a spiral-wound membrane element, wherein the winding shape of each folded membrane sheet conforms to the shape of an Archimedean spiral; comprising:

[0008] Determine the Archimedean spiral expression r1 on the upper page and the Archimedean spiral expression r1′ on the lower page of each folded membrane respectively;

[0009] Wherein, r1=bθ′; θ1≤θ′≤θ2; θ1 represents the starting angle of the upper page in each folded film; θ2 represents the ending angle of the upper page in each folded film; m represents the total number of folded diaphragms; h1 represents the thickness of the diaphragm before folding; h2 represents the thickness of the water production runner cloth; h3 represents the thickness of the feed runner cloth;

[0010] r1′=a+bθ″;θ3≤θ″≤θ4;θ3 represents the starting angle of the next page in each folded film; θ4 represents the ending angle of the next page in each folded film; a=2h1+h3;

[0011] Determine the arc length expression L1 corresponding to r1 and the arc length expression L1′ corresponding to r1′ respectively; determine the length of the upper page of each folded membrane sheet by L1; determine the length of the lower page of each folded membrane sheet by L1′; determine the offset value L0 between the upper and lower pages of each folded membrane sheet by the difference between L1 and L1′, that is, L0 = L1 - L1′; determine that the offset folding size of the membrane sheet can be fully utilized by the offset value L0 between the upper and lower pages of each folded membrane sheet;

[0012] Determine the offset value of each adjacent two folded membranes at the folded end Wherein, D0 represents the total diameter of the water collecting pipe and the innermost circle of the water production channel cloth outside the water collecting pipe; the offset value ΔL of each adjacent folded membrane at the folded end determines that the offset folding size of each adjacent folded membrane can be fully utilized.

[0013] Optionally, the arc length expression L1 corresponding to r1 is as follows:

[0014]

[0015] Optionally, the arc length expression L1′ corresponding to r1′ is as follows:

[0016]

[0017] Optionally, the outermost diameter of the spiral membrane element is set to D, then

[0018] In a second aspect, the present invention provides a storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the method for increasing the effective membrane area of ​​a spiral-wound membrane element.

[0019] In a third aspect, the present invention provides a device comprising: at least one processor, at least one memory, and computer program instructions stored in the memory, which, when executed by the processor, implement the method of increasing the effective membrane area of ​​a spiral-wound membrane element.

[0020] The application of the technical solution of the present invention has at least the following beneficial effects:

[0021] (1) The present invention provides a method, storage medium and device for increasing the effective membrane area of ​​a spiral-wound membrane element, which can solve the problem of insufficient utilization of membrane sheets in the prior art. Specifically, the present invention uses the offset value L0 between the upper and lower pages of each folded membrane sheet to determine that the size of the offset folding of the membrane sheet can be fully utilized; the present invention uses the offset value ΔL at the folding end of each adjacent two folded membrane sheets to determine that the size of the offset folding of each adjacent two folded membrane sheets can be fully utilized; after the spiral-wound membrane element is manufactured using the method for increasing the effective membrane area of ​​the present invention, the upper page of each folded membrane sheet can be fully fitted with the lower page of the adjacent membrane sheet in the counterclockwise direction, and the lower page of each folded membrane sheet can be fully fitted with the upper page of the adjacent membrane sheet in the clockwise direction, ensuring that the membrane sheet is fully utilized. In addition, the present invention can reduce the amount of membrane material and reduce costs on the basis of using the same membrane area.

[0022] (2) The method of increasing the effective membrane area of ​​a spiral-wound membrane element according to the present invention can be used to set the outermost diameter D of the spiral-wound membrane element, the total diameter D0 of the water collecting pipe and the innermost water production channel cloth outside the water collecting pipe, the total number m of folded membrane sheets, the thickness h1 of the membrane sheet before folding, the thickness h2 of the water production channel cloth, and the thickness h3 of the feed channel cloth according to the actual membrane element setting requirements, thereby accurately counting and designing the amount of raw materials used in the membrane element to avoid waste of raw materials.

[0023] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 Schematic diagram of the winding structure of the folded membrane in the spiral-wound membrane element in the embodiment;

[0026] Figure 2 This is a structural diagram of the staggered arrangement of the folded diaphragm and the water production channel;

[0027] Figure 3 This is a schematic diagram of the structure of a spiral wound membrane element when it is rolled;

[0028] Figure 4 is a schematic diagram of the structure of a spiral wound membrane element when m=6;

[0029] Among them, 1. Folding diaphragm, 1.1. Upper page, 1.2. Lower page, 1.3. Feed flow channel cloth, 2. Water production flow channel cloth, 3. Water collecting pipe. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0031] Example:

[0032] See also Figure 1-Figure 4In a spiral-wound membrane element, the winding shape of each folded membrane sheet 1 conforms to the shape of an Archimedean spiral. The manufacturing process for the folded membrane sheet 1 is as follows: a membrane sheet of a certain size is folded to divide it into two parts, the upper membrane sheet being referred to as the upper sheet 1.1 and the lower membrane sheet being referred to as the lower sheet 1.2. A piece of feed channel cloth 1.3 is sandwiched between the upper sheet 1.1 and the lower sheet 1.2, forming the folded membrane sheet 1. Furthermore, the folded end (i.e., the closed end) of the membrane sheet is connected to the innermost outer ring of the water collection pipe 3 along the axis of the water collection pipe 3. Two adjacent folded membrane sheets 1 and the water collection pipe 2 between them are sealed at the boundary with sealing glue to form a membrane bag for collecting the produced water. The sealing glue is applied in an open-end seal, i.e., there is no sealing glue at the closed end of the membrane sheet, and the remaining three sides (i.e., the three non-closed ends of the membrane sheet) are sealed with sealing glue. Sealing glue lines are formed at the locations where the sealing glue is applied.

[0033] During the spiral-wound membrane element production process, multiple layers of water-permeable duct fabric 2 are first wound around the water collection pipe 3 to form the innermost ring of water-permeable duct fabric 2. Subsequently, the folded membrane sheets 1 are first stacked, followed by a layer of water-permeable duct fabric 2, outside the innermost ring of water-permeable duct fabric 2. The folded membrane sheets 1 and water-permeable duct fabric 2 are stacked in this order until the outermost folded membrane sheet 1 is stacked, eliminating the need for further water-permeable duct fabric 2. The entire element is then rolled onto the water collection pipe 3, forming the spiral-wound membrane element. The spacing between the folded ends of each pair of adjacent folded membrane sheets 1 and the innermost ring of water-permeable duct fabric 2 outside the water collection pipe 3 is equal.

[0034] The method for increasing the effective membrane area of ​​a spiral wound membrane element comprises:

[0035] Determine the Archimedean spiral expression r1 of the upper page 1.1 and the Archimedean spiral expression r1′ of the lower page 1.2 in each of the folded membranes 1 respectively;

[0036] Wherein, r1=bθ′; θ1≤θ′≤θ2; θ1 represents the starting angle of the upper page 1.1 in each of the folded membrane sheets 1; θ2 represents the ending angle of the upper page 1.1 in each of the folded membrane sheets 1; m represents the total number of folded membrane sheets 1; h1 represents the thickness of the membrane sheet before folding; h2 represents the thickness of the water channel cloth 2; h3 represents the thickness of the feed channel cloth 1.3; π represents the ratio of pi.

[0037] r1′=a+bθ″;θ3≤θ″≤θ4;θ3 represents the starting angle of the lower page 1.2 in each folded film sheet 1;θ4 represents the ending angle of the lower page 1.2 in each folded film sheet 1;a=2h1+h3;

[0038] Determine the arc length expression L1 corresponding to r1 and the arc length expression L1′ corresponding to r1′ respectively; determine the length of the upper page 1.1 of each folded membrane sheet 1 from L1; determine the length of the lower page 1.2 of each folded membrane sheet 1 from L1′; determine the offset value L0 between the upper page 1.1 and the lower page 1.2 of each folded membrane sheet 1 from the difference between L1 and L1′, that is, L0 = L1 - L1′; determine that the offset folding size of the membrane sheet can be fully utilized from the offset value L0 between the upper page 1.1 and the lower page 1.2 of each folded membrane sheet 1;

[0039] Determine the offset value of each two adjacent folded membranes 1 at the folded end Wherein, D0 represents the total diameter of the water collecting pipe 3 and the innermost circle of the water production channel cloth 2 outside the water collecting pipe 3; the offset value ΔL of each adjacent folded membrane 1 at the folded end determines that the offset folding size of each adjacent folded membrane 1 can be fully utilized.

[0040] The arc length expression L1 corresponding to r1 is as follows:

[0041]

[0042] The arc length expression L1′ corresponding to r1′ is as follows:

[0043]

[0044] Assuming the outermost diameter of the spiral membrane element is D, then

[0045] Set a 4-inch spiral membrane element, set D = 91mm, D0 = 20mm, m = 6, h1 = 0.1397mm, h2 = 0.254mm, h3 = 0.8636mm.

[0046] From this we can get, a=2h1+h3=1.143mm, , r1=bθ′=1.334θ′, r1′=a+bθ″=1.143+1.334θ″, L1=739.463mm, L1′=721.691mm, L0=L1-L1′=17.772mm,

[0047] In addition, the total length of each folded membrane 1 is represented by S, which is the length of the upper page 1.1, the length of the lower page 1.2 and the length of the arc connecting the upper page 1.1 and the lower page 1.2 of each folded membrane 1. The total length of each folded membrane 1 in this embodiment is

[0048] According to the above calculation results, CAD software was used to draw the image of the spiral wound membrane element to verify the accuracy of the method of increasing the effective membrane area of ​​the spiral wound membrane element used in this embodiment. Figure 4 It can be seen that the upper leaf 1.1 of each folded membrane sheet 1 can completely fit with the lower leaf 1.2 of the adjacent membrane sheet in the counterclockwise direction, and the lower leaf 1.2 of each folded membrane sheet 1 can completely fit with the upper leaf 1.1 of the adjacent membrane sheet in the clockwise direction. This fully verifies the accuracy of the method used in this embodiment to increase the effective membrane area of ​​the spiral-wound membrane element, ensuring that the membrane is fully utilized.

[0049] 240 membrane sheets of the same model and length were taken; 120 of them were folded and rolled into 20 4040 spiral-wound membrane elements using the method of this embodiment (each 4040 spiral-wound membrane element uses 6 membrane sheets); in addition, 120 of them were rolled into 20 spiral-wound 4040 membrane elements using the conventional folding method (each 4040 spiral-wound membrane element uses 6 membrane sheets); water production experiments were conducted using the method of this embodiment and the conventional folding method, and the experimental results are shown in Table 1.

[0050] The water production test method is as follows: the test liquid used is 2000ppm sodium chloride, the test pressure is 225psi, and the test liquid recovery rate is controlled at 15%. The water production of each membrane element is measured, and then the measurement results are averaged.

[0051] Table 1 Water production test results

[0052]

[0053]

[0054] The effective membrane area experiments were conducted on 20 4040 spiral-wound membrane elements folded and rolled by the method of this embodiment and 20 4040 spiral-wound membrane elements folded and rolled by the method of this embodiment. The experimental results are shown in Table 2.

[0055] The effective membrane area is measured as follows: After disassembling each membrane element, measure the area of ​​the membrane bag in each membrane element respectively, excluding the area of ​​the sealant line, and take the average value of the measurement results.

[0056] Table 2 Experimental results of effective membrane area

[0057]

[0058] As can be seen from the data in Tables 1 and 2, the method of this embodiment has a significant increase in the average water production and the average effective membrane area compared to the ordinary folding method.

[0059] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for increasing the effective membrane area of ​​a spiral-wound membrane element, wherein the winding shape of each folded membrane sheet (1) conforms to the shape of an Archimedean spiral; wherein: include: Determine the Archimedean spiral expression r1 of the upper page (1.1) and the Archimedean spiral expression r1′ of the lower page (1.2) of each folded membrane (1); Wherein, r1=bθ′; θ1≤θ′≤θ2; θ1 represents the starting angle of the upper page (1.1) in each folded membrane (1); θ2 represents the ending angle of the upper page (1.1) in each folded membrane (1); m represents the total number of folded membranes (1); h1 represents the thickness of the membrane before folding; h2 represents the thickness of the water production channel cloth (2); h3 represents the thickness of the feed channel cloth (1.3); r1′=a+bθ″;θ3≤θ″≤θ4;θ3 represents the starting angle of the lower page (1.2) in each folded membrane (1); θ4 represents the ending angle of the lower page (1.2) in each folded membrane (1); a=2h1+h3; Determine respectively the arc length expression L1 corresponding to r1 and the arc length expression L1′ corresponding to r1′; determine the length of the upper page (1.1) of each folded membrane (1) by L1; determine the length of the lower page (1.2) of each folded membrane (1) by L1′; determine the offset value L0 between the upper page (1.1) and the lower page (1.2) of each folded membrane (1) by the difference between L1 and L1′, that is, L0=L1-L1′; determine the size of the membrane offset folding by the offset value L0 between the upper page (1.1) and the lower page (1.2) of each folded membrane (1) to be fully utilized; Determine the offset value of each adjacent two folded membranes (1) at the folded ends Wherein, D0 represents the total diameter of the water collecting pipe (3) and the innermost ring of the water production channel cloth (2) outside the water collecting pipe (3); the offset value ΔL of each two adjacent folded membrane sheets (1) at the folded end determines that the size of the offset folding of each two adjacent folded membrane sheets (1) can be fully utilized; The arc length expression L1 corresponding to r1 is as follows: The arc length expression L1′ corresponding to r1′ is as follows:

2. The method for increasing the effective membrane area of ​​a spiral-wound membrane element according to claim 1, characterized in that: Assuming the outermost diameter of the spiral membrane element is D, then 3. A storage medium, characterized in that Computer program instructions are stored thereon, and when the computer program instructions are executed by a processor, the method for increasing the effective membrane area of ​​a spiral-wound membrane element as claimed in any one of claims 1 to 2 is implemented.

4. The device is characterized in that include: At least one processor, at least one memory, and computer program instructions stored in the memory, which, when executed by the processor, implement the method for increasing the effective membrane area of ​​a spiral-wound membrane element as described in any one of claims 1 to 2.

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