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

Abstract

The invention relates to the technical field of spiral-wound membrane elements, in particular to a method for increasing the effective membrane area of a spiral-wound membrane element, a storage medium and equipment. The method comprises the following steps: respectively determining an Archimedes spiral expression r1 of an upper page and an Archimedes spiral expression r1'of a lower page in each folded diaphragm; respectively determining an arc length expression L1 corresponding to the r1 and an arc length expression L1'corresponding to the r1 '; determining the dislocation value L0 of the upper page and the lower page of each folding diaphragm according to the difference value of L1 and L1 '; and determining a dislocation value delta L of every two adjacent folding membranes at the folding end. A computer program instruction is stored in the storage medium; the apparatus includes at least one processor, at least one memory, and computer program instructions stored in the memory, the method being implemented when the computer program instructions are executed by the processor. According to the invention, the diaphragm can be fully 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 for its advantages of simplicity, high packing density, good water quality, easy automation and maintenance. At present, the membrane elements used in filtration devices in membrane technology mainly include spiral wound membrane elements, hollow fiber membrane elements, tubular membrane elements and plate-and-frame membrane elements. Spiral wound membrane elements have a large market share due to their compact structural design and low price.

[0003] The spiral membrane element is mainly composed of a membrane sheet, a feed channel cloth, a water production channel cloth and a water collection pipe, which are combined and rolled in a certain order. Among them, multiple layers of water production channel cloth are first wound outside the water collection pipe as the innermost circle of water production channel cloth outside the water collection pipe; then, on the outer side of the innermost circle of water production channel cloth, the folded membrane sheet is first stacked, and then a layer of water production channel cloth is stacked. In this order, the folded membrane sheet and the water production channel cloth are stacked in sequence until the outermost folded membrane sheet is stacked. It is no longer necessary to stack the water production channel cloth, and then the whole is rolled up on the water collection pipe to form a spiral membrane element. Among them, the production process of the folded membrane sheet is as follows: fold a membrane sheet of a certain size, divide the membrane sheet into two parts, the upper membrane sheet is called the upper page, and the lower membrane sheet is called the lower page. A feed channel cloth is sandwiched between the upper page and the lower page to form a folded membrane sheet. In addition, the folded end (i.e., closed end) of the diaphragm is connected to the water collecting pipe along the axial direction of the water collecting pipe, and two adjacent folded diaphragms and the water production flow channel cloth therebetween are sealed at the boundary with sealing glue to form a membrane bag for collecting produced water, and the sealing glue is sealed in an open shape, i.e., 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 collecting 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, in the folding process of the membrane before rolling, generally only enough size is considered for the bottom edge of the membrane to fully bond with the water production channel cloth and the sealing glue, while the problem of insufficient utilization of the membrane is ignored. If the membrane is directly folded in half or the size of the offset folding is not appropriate, the membrane will not be fully utilized, resulting in a reduction in the effective water treatment area, thereby reducing 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 object of the present invention is to provide a method, storage medium and device for increasing the effective membrane area of ​​a spiral wound membrane element. The specific technical scheme 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 of the upper page and the Archimedean spiral expression r1′ of the lower page in each of the folded membranes respectively;

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

[0010] r1′=a+bθ″;θ3≤θ″≤θ4;θ3 represents the starting angle of the next page in each folded film sheet;θ4 represents the ending angle of the next page in each folded film sheet;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 misalignment value L0 between the upper page and the lower page of each folded membrane sheet by the difference between L1 and L1′, that is, L0=L1-L1′; determine the size of the misaligned folding of the membrane sheet by the misalignment value L0 between the upper page and the lower page of each folded membrane sheet so that it can be fully utilized;

[0012] Determine the offset value of each adjacent two folded membrane sheets 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 sheet at the folded end determines that the size of the offset folding of each adjacent folded membrane sheet 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 implement the method of increasing the effective membrane area of ​​a spiral membrane element when the computer program instructions are executed by the processor.

[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 membranes in the prior art. Specifically, the present invention uses the offset value L0 between the upper page and the lower page of each folded membrane to determine that the size of the offset folding of the membrane can be fully utilized; the present invention uses the offset value ΔL at the folding end of each adjacent two folded membranes to determine that the size of the offset folding of each adjacent two folded membranes can be fully utilized; after the spiral-wound membrane element is manufactured by using the method for increasing the effective membrane area of ​​the spiral-wound membrane element in the present invention, the upper page of each folded membrane can be fully fitted with the lower page of the adjacent membrane in the counterclockwise direction, and the lower page of each folded membrane can be fully fitted with the upper page of the adjacent membrane in the clockwise direction, ensuring that the membrane is fully utilized. In addition, the present invention can reduce the material used for the membrane 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 of 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 being able to accurately count and design the amount of raw materials used in the membrane element to avoid waste of raw materials.

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

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

[0025] Figure 1 is a schematic diagram of the winding shape structure of the folded membrane in the spiral wound membrane element in the embodiment;

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

[0027] Figure 3 It is a schematic diagram of the structure of the 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. folded diaphragm, 1.1. upper page, 1.2. lower page, 1.3. feed flow cloth, 2. water production flow cloth, 3. water collecting pipe. DETAILED DESCRIPTION

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

[0031] Example:

[0032] See also Figure 1-Figure 4 In the spiral membrane element, the winding shape of each folded membrane sheet 1 conforms to the shape of the Archimedean spiral; wherein, the manufacturing process of the folded membrane sheet 1 is as follows: a membrane sheet of a certain size is folded to divide the membrane sheet into two parts, the upper membrane sheet is called the upper page 1.1, and the lower membrane sheet is called the lower page 1.2, and a piece of feed channel cloth 1.3 is sandwiched between the upper page 1.1 and the lower page 1.2 to form a folded membrane sheet 1. In addition, the folded end (i.e., the closed end) of the membrane sheet is connected to the innermost circle of the water production channel cloth 2 outside the water collection pipe 3 along the axial direction of the water collection pipe 3, and two adjacent folded membrane sheets 1 and the water production channel cloth 2 between the two are sealed at the boundary by sealing glue to form a membrane bag for collecting water production. The sealing glue is sealed in an open shape, that is, there is no sealing glue at the closed end of the membrane sheet, and the other 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 positions where the sealing glue is applied.

[0033] During the process of rolling the spiral membrane element, firstly roll a plurality of water production channel cloth 2 outside the water collecting pipe 3 as the innermost circle of water production channel cloth 2 outside the water collecting pipe 3; then, on the outer side of the innermost circle of water production channel cloth 2, first stack the folded membrane sheet 1, then stack a layer of water production channel cloth 2, and then stack the folded membrane sheet 1 and the water production channel cloth 2 in this order, until the outermost layer of the folded membrane sheet 1 is stacked, and no more water production channel cloth 2 is needed, and then the whole is rolled up on the water collecting pipe 3 to form a spiral membrane element. Among them, the distance between the folded ends of each two adjacent folded membrane sheets 1 and the innermost circle of water production channel cloth 2 outside the water collecting 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 production channel cloth 2; h3 represents the thickness of the feed channel cloth 1.3; π represents the circumference of a circle;

[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 by L1; determine the length of the lower page 1.2 of each folded membrane sheet 1 by L1′; determine the misalignment value L0 between the upper page 1.1 and the lower page 1.2 of each folded membrane sheet 1 by the difference between L1 and L1′, that is, L0=L1-L1′; determine the size of the misaligned folding of the membrane sheet by the misalignment value L0 between the upper page 1.1 and the lower page 1.2 of each folded membrane sheet 1 so that it can be fully utilized;

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

[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 = 1.143 mm, , 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 sheet 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 arc length between the upper page 1.1 and the lower page 1.2 of each folded membrane sheet 1. The total length of each folded membrane sheet 1 in this embodiment is

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

[0049] 240 membrane sheets of the same model and length were taken; among them, 120 sheets were folded and rolled into 20 4040 spiral-wound membrane elements (each 4040 spiral-wound membrane element used 6 membrane sheets) using the method of this embodiment; in addition, 120 sheets were rolled into 20 spiral-wound 4040 membrane elements (each 4040 spiral-wound membrane element used 6 membrane sheets) using the ordinary folding method; the water production test was carried out using the method of this embodiment and the ordinary 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 when 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 method for measuring the effective membrane area is as follows: after disassembling each membrane element, measure the area of ​​the membrane bag in each membrane element respectively. The area needs to exclude 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] From the data in Tables 1 and 2, it can be seen that the method of this embodiment has a significant increase in the average water production and the average effective membrane area compared with the ordinary folding method.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope 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; characterized in that: include: Determine the Archimedean spiral expression r1 of the upper page (1.1) and the Archimedean spiral expression r′1 of the lower page (1.2) in each of the folded membranes (1); 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 sheets before folding; h2 represents the thickness of the water production channel cloth (2); h3 represents the thickness of the feed channel cloth (1.3); r′1=a+bθ″;θ3≤θ″≤θ4;θ3 represents the starting angle of the lower page (1.2) in each folded membrane sheet (1); θ4 represents the ending angle of the lower page (1.2) in each folded membrane sheet (1); a=2h1+h3; Determine respectively the arc length expression L1 corresponding to r1 and the arc length expression L′1 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 L′1; 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 L′1, that is, L0=L1-L′1; determine the size of the offset folding of the membrane by the offset value L0 between the upper page (1.1) and the lower page (1.2) of each folded membrane (1) so that it can be fully utilized; Determine the offset value of each two adjacent folded membrane sheets (1) at the folded ends Wherein, D0 represents the total diameter of the water collecting pipe (3) and the innermost circle of the water producing channel cloth (2) outside the water collecting pipe (3); the offset value ΔL of each adjacent two folded membrane sheets (1) at the folded end determines that the size of the offset folding of each adjacent two folded membrane sheets (1) can be fully utilized.

2. The method for increasing the effective membrane area of ​​a spiral wound membrane element according to claim 1, characterized in that: The arc length expression L1 corresponding to r1 is as follows:

3. The method for increasing the effective membrane area of ​​a spiral wound membrane element according to claim 1, characterized in that: The arc length expression L′1 corresponding to r′1 is as follows:

4. 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, 5. 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 4 is implemented.

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

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