Spiral membrane element and spiral membrane module

Abstract

The present invention provides a spiral membrane element and a spiral membrane module, which do not require glass fiber reinforcement, have a small number of components, and can reduce bypass flow and increase effective membrane area. The spiral membrane element of the present invention has a center pipe 5 with a hole, a roll body R wound on the center pipe 5 and containing a separation membrane 1, and an outer layer covering material provided on the outer periphery of the roll body R, wherein the outer layer covering material contains an outer layer covering flow path material 21 that covers the outer periphery of the roll body R to form a flow path outside the roll body R while blocking the inflow of a feed liquid 7. The outer layer covering flow path material 21 preferably contains a sheet 21a that covers the outer periphery of the roll body R and a porous material 21b that covers the sheet 21a.

Description

Technical Field

[0001] This invention relates to helical membrane elements (hereinafter sometimes simply referred to as "membrane elements") and helical membrane modules using the helical membrane elements. Background Technology

[0002] Traditionally, spiral membrane elements are manufactured by winding a separation membrane (as a flat sheet membrane), a permeate flow path material, and a supply flow path material around a perforated central tube, and then constructing an FRP (fiber-reinforced plastic) outer covering material around the periphery of the resulting winding. In this case, the ATD (anti-telescoping device) installed at both ends of the membrane element is integrated during the FRP construction.

[0003] By installing a U-shaped seal on the ATD, bypass flow between the membrane element and the container is prevented. When bypass flow occurs, the supply liquid flowing through the supply-side flow path inside the membrane element is correspondingly reduced, resulting in decreased energy efficiency in the filtration process. Pressure loss occurs as the supply liquid flows through the supply-side flow path inside the membrane element, but at the outer periphery of the membrane element (between the outer peripheral surface of the membrane element and the inner surface of the container), the pressure varies in a stepped manner before and after the U-shaped seal. When the U-shaped seal is installed on the upstream ATD, the internal pressure acts on the outer covering FRP.

[0004] The outer cover FRP is typically made of GFRP (glass FRP), which possesses sufficient strength due to its resistance to internal pressure in the direction reinforced with glass fibers. When the U-shaped seal is installed on the downstream ATD, the pressure acting on the outer cover FRP becomes external pressure. In this case, the cross-section of the outer cover FRP (the section orthogonal to the axial direction of the membrane element) deforms into an elliptical or triangular shape, resulting in the internal windings being compressed by the FRP, leading to defects such as wrinkles on the membrane. Therefore, the U-shaped seal is essentially installed on the upstream ATD.

[0005] Spiral membrane elements deteriorate over time due to years of use and surface fouling, resulting in a decline in performance. While fouling can be partially reversed through physical methods such as flushing (increasing the flow rate of the feed liquid) or chemical cleaning, it will eventually reach its limit, necessitating replacement of the membrane element. Used membrane elements are sometimes reused for applications where high performance is not required, but most are disposed of through methods such as landfill and incineration.

[0006] There are also technologies that do not rely on the GFRP outer layer covering material described above. For example, Patent Document 1 discloses a spiral membrane element that covers the outer periphery of the wound body with a permeable side flow path material. However, in the embodiment, the outer peripheral surface of the permeable side flow path material is fixed with a membrane strip and a brine seal (U-shaped seal) is provided. It is clear that the invention of Patent Document 1 envisions a technology in which a membrane strip exists on the outer periphery of the permeable side flow path material and the supply liquid flows inside it.

[0007] In addition, Patent Document 2 discloses a cylindrical mesh provided on the outer periphery of the wound body instead of the GFRP outer layer covering material as described above, but this invention is also based on the premise of providing a sealing material (U-shaped seal) on the ATD of the membrane element.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-205954

[0011] Patent Document 2: Japanese Patent Application Publication No. 2000-354742 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] Incidentally, the disposal of replaced membrane elements is a major problem. Landfill disposal is not sustainable due to limited site capacity, and the fact that membrane elements, which are mostly plastic, cannot decompose underground and thus remain semi-permanently underground makes it unsustainable. Furthermore, the glass fibers contained in the outer FRP covering are non-combustible and remain in the incineration ash, making ash disposal difficult.

[0014] When a membrane strip is used as the outer covering material and a seal is provided on the upstream side of the membrane element, as described in Patent Document 1, although glass fiber can be omitted, the following problem sometimes occurs: the membrane element deforms due to internal pressure, resulting in the separation membrane breaking during operation or cleaning.

[0015] Furthermore, when a cylindrical mesh is placed on the outer periphery of the winding body as described in Patent Document 2, the following problem exists: the raw water flows through the gap between the outer periphery of the mesh and the pressure vessel, thus becoming a bypass flow, which reduces the filtration efficiency.

[0016] It should be noted that in conventional spiral membrane elements, the winding body and the ATD are integrated through an outer covering material. Because the ATD has a U-shaped seal around its periphery, it is difficult to increase the outer diameter of the winding body independently of the ATD's outer diameter. Furthermore, this structure increases the number of components.

[0017] Therefore, the object of the present invention is to provide a spiral membrane element and a spiral membrane module, wherein the spiral membrane element does not require glass fiber reinforcement, has a small number of components, and can reduce bypass flow and increase effective membrane area.

[0018] means for solving problems

[0019] The above objectives can be achieved through the following invention.

[0020] That is, the spiral membrane element of the present invention has a perforated central tube, a wound body wound on the central tube and including a separation membrane, and an outer covering material disposed on the outer periphery of the wound body. The outer covering material is characterized in that it includes an outer covering flow path material, which forms a flow path on the outside of the wound body while covering the outer periphery of the wound body to block the inflow of the supply liquid.

[0021] According to the spiral membrane element of the present invention, the outer layer covering flow path material covers the outer periphery of the winding body, thereby blocking the inflow of the supply liquid, while forming a flow path outside the winding body. Therefore, the liquid flowing inside the winding body (the supply liquid for membrane separation) and the liquid flowing in the flow path of the outer layer covering flow path material (the supply liquid for non-membrane separation) form independent flow paths, thus allowing independent control of the pressure distribution of the two flow paths. Therefore, since the pressure difference between the two flow paths can be reduced, glass fiber reinforcement is not required. Furthermore, even if the outer periphery of the membrane element is tightly sealed to the inner surface of the pressure vessel, the supply liquid can still flow inside the outer layer covering flow path material, thus reducing bypass flow and increasing the effective membrane area by increasing the outer diameter of the winding body. In addition, since bypass flow is reduced, upstream ATD and U-shaped seals are not required, reducing the number of components. As a result, a spiral membrane element that does not require glass fiber reinforcement, has a small number of components, and reduces bypass flow while increasing the effective membrane area can be provided.

[0022] In the above description, the outer layer covering flow path material preferably comprises a sheet covering the outer periphery of the wound body and a porous material covering the sheet. According to this structure, the inflow of the supply liquid can be blocked by covering the outer periphery of the wound body with the sheet, and a flow path can be formed on the outside of the wound body using the porous material. Furthermore, by using a porous material, pressure loss is easier to control, and the pressure difference between the two flow paths is easier to reduce.

[0023] Furthermore, when used in a pressure vessel, the outer diameter, based on the outer periphery of the outer covering material, is preferably 99% to 100% of the inner diameter of the pressure vessel. By using such an outer diameter, the gap between the outer covering material and the inner surface of the pressure vessel is reduced, which can effectively reduce bypass flow and increase the effective membrane area.

[0024] Furthermore, it is preferable to have a detachable anti-stretch material on the downstream side of the aforementioned winding. By making the anti-stretch material used to suppress stretching detachable, the amount of waste to be processed can be reduced, and the anti-stretch material can be reused. In addition, the process of integrating the anti-stretch material with an outer covering material is eliminated, simplifying the installation process.

[0025] At this point, the aforementioned anti-stretch member is preferably provided with an outer peripheral side baffle disposed on the downstream side near the outer periphery of the aforementioned winding body and an inner peripheral side baffle disposed on the downstream side near the inner periphery of the aforementioned winding body. The detailed reasoning is explained later: there is a concentration distribution in the concentrate flowing out of the spiral membrane element, with the concentration decreasing near the outer and inner periphery of the winding body. In this invention, since the feed liquid flows in the outer layer of the flow path material covering the winding body without being concentrated, the concentration of the concentrate near the outer periphery is lower than usual. Low concentration refers to low osmotic pressure; although a high flux can be expected simply by allowing it to flow across the membrane surface, it is inefficient to flow through a portion that does not undergo membrane separation even in the next stage. Therefore, by providing the outer and inner peripheral side baffles, the concentrate can be stirred and mixed, and the efficiency of membrane separation in the next stage can be improved.

[0026] The aforementioned anti-stretch material is preferably mounted on the central tube extending downstream of the aforementioned winding body. By utilizing the central tube, the anti-stretch material can be easily assembled and disassembled.

[0027] On the other hand, the spiral membrane module of the present invention is characterized in that the spiral membrane module includes a spiral membrane element as described in any of the above claims and a pressure vessel that houses the spiral membrane element, and the outer diameter based on the outer periphery of the outer covering material is 99% to 100% of the inner diameter of the pressure vessel.

[0028] According to the spiral membrane module of the present invention, by using the spiral membrane element as described above and making the outer diameter of the membrane element 99% to 100% of the inner diameter of the pressure vessel, the aforementioned effects can be obtained. That is, while the outer layer of the membrane element covering the flow path material blocks the inflow of the supply liquid by covering the outer periphery of the winding body, a flow path is formed outside the winding body. Therefore, the liquid flowing inside the winding body (the supply liquid for membrane separation) and the liquid flowing inside and around the porous material (the supply liquid for non-membrane separation) form independent flow paths, allowing independent control of the pressure distribution of the two flow paths. Therefore, since the pressure difference between the two flow paths can be reduced, glass fiber reinforcement is not required. Furthermore, even if the outer periphery of the membrane element is tightly sealed to the inner surface of the pressure vessel, the supply liquid can still flow inside the outer layer covering the flow path material, thus reducing bypass flow and increasing the effective membrane area by increasing the outer diameter of the winding body. In addition, since bypass flow can be reduced, upstream ATDs and U-shaped seals are not required, reducing the number of components. The result is a spiral membrane module that does not require glass fiber reinforcement, has fewer components, and can reduce bypass flow and increase the effective membrane area.

[0029] Invention Effects

[0030] The present invention provides a spiral membrane element and a spiral membrane module, wherein the spiral membrane element does not require glass fiber reinforcement, has fewer components, and can reduce bypass flow and increase effective membrane area. Attached Figure Description

[0031] Figure 1 This is a cross-sectional view showing an example of the state in which the spiral membrane element of the present invention is housed in a pressure vessel; it is an enlarged view of a portion of the view.

[0032] Figure 2A This is a top view showing an example of a separation membrane unit used in the spiral membrane element of the present invention.

[0033] Figure 2B This is a front view showing an example of a separation membrane unit used in the spiral membrane element of the present invention.

[0034] Figure 2C This is a front view showing an example of the state of the separation membrane unit to be used in the spiral membrane element of the present invention before it is stacked and wound.

[0035] Figure 3 This is a perspective view showing an example of a winding body with a diaphragm and supply-side flow path material wound around a central tube, after a portion has been cut off.

[0036] Figure 4 A perspective view showing an example of an anti-stretch material that can be used in the spiral membrane element of the present invention.

[0037] Figure 5A This is a front view showing another example of the state of the separation membrane unit to be used in the spiral membrane element of the present invention before it is stacked and wound.

[0038] Figure 5B This is a front view showing another example of the state of the separation membrane unit to be used in the spiral membrane element of the present invention before it is stacked and wound.

[0039] Figure 5C This is a front view showing another example of the state of the separation membrane unit to be used in the spiral membrane element of the present invention before it is stacked and wound.

[0040] Figure 5D This is a front view showing another example of the state of the separation membrane unit to be used in the spiral membrane element of the present invention before it is stacked and wound.

[0041] Figure 6A A front view showing another example of an anti-stretching material that can be used in the spiral membrane element of the present invention.

[0042] Figure 6B A front view showing another example of an anti-stretching material that can be used in the spiral membrane element of the present invention.

[0043] Figure 6C A front view showing another example of an anti-stretching material that can be used in the spiral membrane element of the present invention.

[0044] Figure 7A This is a cross-sectional view showing the main part of another example of the spiral membrane element of the present invention.

[0045] Figure 7B This is a cross-sectional view showing the main part of another example of the spiral membrane element of the present invention.

[0046] Figure 8A This is a cross-sectional view showing the main part of another example of the spiral membrane element of the present invention.

[0047] Figure 8B This is a cross-sectional view showing the main part of another example of the spiral membrane element of the present invention.

[0048] Figure 8C This is a cross-sectional view showing the main part of another example of the spiral membrane element of the present invention. Detailed Implementation

[0049] (Helical membrane element)

[0050] The spiral membrane element E of the present invention is, for example, as shown in the example below. Figure 1The diagram shows a perforated central tube 5, a wound body R wound around the central tube 5 and containing a separation membrane 1, and an outer covering material disposed on the outer periphery of the wound body R. The membrane element E is, for example, as shown... Figure 3 The device typically includes: a plurality of membranes L, which sandwich a permeate-side flow path material 3 between opposing separation membranes 1; a supply-side flow path material 2 sandwiched between the membranes L; a perforated central tube 5 on which the membranes L and the supply-side flow path material 2 are wound; and a sealing portion that prevents mixing between the supply-side flow path and the permeate-side flow path.

[0051] A supply-side flow path and / or a permeate-side flow path can be formed on the surface of the separation membrane 1 by providing irregularities or grooves. In this case, the supply-side flow path material 2 and / or the permeate-side flow path material 3 can be omitted.

[0052] In this embodiment, an example is shown where the sealing portion includes a two-end sealing portion 11 and an outer peripheral sealing portion 12. In the sealing portion, the two-end sealing portion 11 is a sealing portion that seals both ends of the diaphragm L in the axial direction A1 using an adhesive. The outer peripheral sealing portion 12 is a sealing portion that seals the end of the outer peripheral front end of the diaphragm L using an adhesive.

[0053] Furthermore, in this invention, such as Figure 3 As shown, the preferred embodiment has a central side sealing portion 13 that seals the base ends of the perforated central tube 5 and the diaphragm L using an adhesive. The membrane element of this embodiment has a wound body R obtained by winding the diaphragm L and the supply-side flow path material 2 onto the central tube 5 through such a central side sealing portion 13.

[0054] The aforementioned wound body R can, for example, be obtained through... Figures 2A-2C The manufacturing process is shown. Figure 2A This is a top view of the separation membrane unit U. Figure 2B This is the front view of the separation membrane unit U. Figure 2C This is a front view showing the state before the separation membrane unit U is stacked and wound. Additionally, Figure 3 This is a perspective view of a winding body R, with a portion cut off, showing an example of a diaphragm L and supply-side flow path material 2 wound around a central tube 5.

[0055] First, such as Figure 2A and Figure 2BAs shown, a separation membrane unit U is prepared, which is obtained by layering a component obtained by placing a supply-side flow path material 2 between the separation membranes 1 after folding them in half, and a permeation-side flow path material 3. Adhesives 4 and 6 for forming the end-capping seals 11 and the outer peripheral seals 12 are applied to both ends of the permeation-side flow path material 3 in the axial direction A1 and to the front end of the winding. At this time, a protective tape can be attached to the folded portion of the separation membrane 1.

[0056] There are no particular restrictions on adhesives 4 and 6; any conventionally known adhesives may be used. Specifically, for example, all conventionally known adhesives such as urethane adhesives and epoxy adhesives may be used.

[0057] Next, as Figure 2C As shown, the same number of separation membrane units U as the membrane sheet L are stacked on the permeate flow path material 3, which has a portion that is longer than other components, thereby preparing a stack of separation membrane units U. At this time, by also applying adhesive to both ends of the extended portion of the lowermost permeate flow path material 3 in the axial direction A1, a central side seal portion 13 can be formed.

[0058] Next, as Figure 2C As shown, the perforated central tube 5 is rotated in the direction of the arrow, thereby winding multiple separation membrane units U onto the central tube 5. At this time, the opposing separation membranes 1 and the permeation side flow path material 3 are bonded together by adhesives 4 and 6 to form a membrane sheet L having end sealing portions 11 and outer peripheral sealing portions 12.

[0059] The results are as follows Figure 3 The diagram shows a wound body R formed by winding a diaphragm L and the supply-side flow path material 2 onto a central tube 5. To adjust the length of the wound body R in the axial direction A1, the ends of the sealed wound body R can be trimmed, etc.

[0060] In conventional membrane elements E, an upstream end member such as a sealing frame is provided on the upstream side of the winding body R, and a downstream end member such as an anti-stretching material is fixedly provided on the downstream side. However, in the membrane element E of the present invention, as... Figure 1 As shown, it is not necessary to provide an upstream end member integrated with the winding body R. Furthermore, the anti-stretch material 25 is not an anti-stretch material integrated with the winding body R, but rather preferably a detachable anti-stretch material 25.

[0061] In a typical 8-inch diameter spiral membrane element, approximately 15 to 30 sets of membrane sheets L are wound. However, in this invention, the outer diameter of the winding body R is larger than before, and the length of the membrane sheet L (the length perpendicular to the axial direction A1) is longer than before. This increases the effective membrane area of ​​the composite semi-permeable membrane, enabling large-scale processing and thus improving processing efficiency.

[0062] When using the above membrane element E, such as Figure 1 As shown, membrane element E is housed within pressure vessel 30 (container), and supply liquid 7 is supplied from one end face of the membrane element. The supplied supply liquid 7 flows along the supply-side flow path material 2 in a direction parallel to the axial direction A1 of the central tube 5, and is discharged from the other end face of the membrane element in the form of concentrate 9. Additionally, as the supply liquid 7 flows along the supply-side flow path material 2, the permeate 8 that permeates through the separation membrane 1 flows along the permeate-side flow path material 3, then flows into the interior of the central tube 5 through the opening 5a, and is discharged from the end of the central tube 5. Regarding... Figure 1 The spiral membrane module shown will be described in detail later.

[0063] (Outer covering material)

[0064] The invention is characterized in that the outer covering material disposed on the outer periphery of the winding body R includes an outer covering flow path material 21, which, while covering the outer periphery of the winding body R to block the inflow of the supply liquid 7, forms a flow path on the outside of the winding body R. The outer covering flow path material 21 can be made of, for example... Figure 8B The sheet 21s shown, which has protrusions or grooves on the outside, is formed individually, but from the viewpoint of properly controlling the pressure loss of the flow path formed on the outside of the winding body R, it is preferable to be formed of multiple materials.

[0065] In this embodiment, for example, Figure 1 The diagram illustrates an example where the outer layer covering flow path material 21 disposed on the outer periphery of the wound body R comprises a sheet 21a covering the outer periphery of the wound body R and a porous material 21b covering the sheet 21a. In this way, in the present invention, a structure omitting the outer layer covering FRP can be formed.

[0066] The outer FRP covering has the function of withstanding internal pressure, but the porous material 21b, which does not contain reinforcing materials such as glass fiber, does not have the function of withstanding internal pressure. Therefore, a structure that is not easy to apply internal pressure is adopted. For this reason, the U-shaped seal is removed so that a small amount of supply fluid 7 flows within the layer of porous material 21b. Similar to the flow of supply fluid 7 inside the winding body R, the supply fluid 7 also flows inside the porous material 21b outside the winding body R. Thus, the pressure loss in the two flow paths is basically equal, and a state in which neither internal nor external pressure acts on the sheet 21a covering the outer periphery of the winding body R.

[0067] That is, such as Figure 1 As shown in the enlarged view, most of the supplied liquid 7 is supplied to the winding body R inside the sheet 21a, becoming the internal flow 7a of the element, while only a portion of the supplied liquid 7 is supplied to the porous material 21b, becoming the bypass flow 7b.

[0068] It should be noted that there are two regions on the outermost periphery of the wound body R: the region where the supply-side flow path material 2 is located and the region where the separation membrane 1 of the diaphragm L is located. The upper enlarged view shows the state of the former, and the lower enlarged view shows the state of the latter.

[0069] In this invention, the outer layer covering flow path material 21 (sheet 21a in this embodiment) covers the outer periphery of the wound body R, thereby blocking the inflow of the supply liquid 7, and the pressure loss of the flow path formed outside the wound body R can be independently controlled. The pressure loss can be adjusted, for example, by adjusting the thickness, number of layers, pore size, porosity, direction of the weave structure, and direction of the textile structure of the porous material 21b.

[0070] In this embodiment, an example is shown where the outer diameter, based on the outer periphery of the outer covering material, is 100% of the inner diameter of the pressure vessel 30, i.e., there is no gap between the porous material 21b and the pressure vessel 30.

[0071] In this invention, the gap may also exist, but the outer diameter relative to the inner diameter of the pressure vessel 30, based on the outer periphery of the outer covering material, is preferably 99.0% to 100.0%, more preferably 99.5% to 100.0%, and even more preferably 100.0%. By using an outer diameter within this range, the gap between the sheet covering the outer periphery of the winding and the inner surface of the pressure vessel is reduced, which can more effectively reduce bypass flow and increase the effective membrane area. Furthermore, for the same reason, the size of the gap between the porous material 21b and the pressure vessel 30 is preferably 0 mm to 1 mm, more preferably 0 mm to 0.5 mm, and most preferably 0 mm.

[0072] In this invention, as described above, the volume of the winding body R inside the pressure vessel 30 can be increased, thereby accommodating more separation membranes 1 (flat sheet membranes). That is, the membrane area of ​​each element is increased, thereby increasing the permeate flow rate. Moreover, the outer diameter of the winding body R can be increased by about 2%, and the axial length can be increased by about 2% by omitting the upstream side ATD, thus increasing the membrane area and permeate flow rate of each element by about 6%.

[0073] From the viewpoint of properly controlling bypass flow and pressure distribution by generating moderate pressure loss, the porosity of the porous material 21b is preferably 5% to 80%, more preferably 10% to 50%.

[0074] From the viewpoint of properly controlling the bypass flow and pressure distribution by generating a moderate pressure loss, the thickness of the porous material 21b (total thickness in the case of a multilayer structure) is preferably 0.2 mm to 2 mm, more preferably 0.5 mm to 1.2 mm.

[0075] As the porous material 21b, any material that can be used as the supply-side flow path material 2 or through the side flow path material 3 (described later) or similar materials, such as nonwoven fabric, polymer porous membrane, cloth, etc., can be used. However, from the viewpoint of pressure loss, processability, etc., a material that can be used as through the side flow path material 3 is preferred.

[0076] As a specific porous material 21b, weft-knitted materials such as plain knit fabric and purl knit fabric, warp-knitted materials such as warp-knitted fabric, and plain weave fabric are preferred. When using warp-knitted semi-knitted fabric and double-comb warp plain knitted fabric, which are often used in the permeable side flow path material 3, it is preferable to use them in a direction where the direction in which the grooves / ridges are formed is orthogonal to the axial direction A1 of the membrane element E. This is because the flow resistance of the bypass flow increases, which can reduce the flow rate of the supply fluid leaking in the bypass.

[0077] Because the porous material 21b uses a fine-mesh material, it is conceivable that during actual filtration operation, turbid components contained in the supply liquid may accumulate and cause blockage. When blockage occurs, the pressure distribution in the gap between the membrane element E and the pressure vessel 30 becomes similar to that when a U-shaped seal is used, with internal pressure acting on the inner surface of the porous material 21b. Although the porous material 21b does not have the function of withstanding internal pressure, in this invention, since the outer diameter of the state in which the porous material 21b is wound on the winding body R is made to be substantially the same as the inner diameter of the pressure vessel 30, even if internal pressure acts on the inner surface of the porous material 21b, during the slight expansion phase, the outer surface of the porous material 21b contacts the inner wall of the pressure vessel 30, so no particularly adverse situation occurs.

[0078] On the other hand, the sheet 21a covering the outer periphery of the wound body R can be a film, sheet, tape, etc. By using such a sheet 21a to cover the outer periphery of the wound body R, the outer diameter of the wound body R can be adjusted with high precision, or by constraining and fixing the outer periphery of the wound body R, a series of processes can be smoothly performed. From this point of view, it is preferable to use a sheet 21a with adhesive, especially an adhesive tape with a substrate made of stretched polypropylene.

[0079] The outer layer covering flow path material 21 can be formed by sequentially covering sheet 21a and porous material 21b while the outer periphery of the wound body R is temporarily fixed, or for example... Figure 5A The sheet 21a and the porous material 21b are continuously covered by the winding of the winding body R.

[0080] That is, a sheet 21a can be extended from the front end of any of the through-side flow path materials 3 used in forming the wound body R, or from the front end of any of the through-side flow path materials 3 that are extended therefrom, via the adhesive portion 21c. When the wound body R is wound, the sheet 21a is used to cover its outer periphery. If a sheet 21a with adhesive is used, both covering and fixing can be performed simultaneously.

[0081] At this point, it is particularly preferable that the permeate flow path material 3, which extends towards the central tube 5, also extends outward to the peripheral side, and that the sheet 21a is glued to its front end by the adhesive portion 21c. This permeate flow path material 3 is a structure that is sealed together with the separation membrane 1 during the formation of the membrane L, so that the supply liquid 7 flows in the permeate flow path material 3 and does not mix with the permeate liquid 8.

[0082] The covering process using porous material 21b can be performed independently of the covering process using sheet 21a, or for example... Figure 5B As shown, porous material 21b is glued to the front end of sheet 21a via adhesive portion 21d, and adhesive portion 21d is covered in a continuous process with covering sheet 21a. The covered porous material 21b can be fixed by adhesively bonding the overlapping portion to sheet 21a.

[0083] It should be noted that the outer covering material may consist only of the outer covering flow path material 21, or it may include fixing tape, etc. However, it is preferable not to include reinforcing fibers such as glass fiber.

[0084] (Other embodiments of the outer covering material)

[0085] By extending the front end of any one of the permeable side flow path materials 3 used in forming the wound body R, the extended portion can be used as a porous material 21b covering the sheet 21a. For example, it can be as follows: Figure 5C As shown, the permeate flow path material 3, which extends towards the central tube 5, also extends outward to a length equivalent to that of the porous material 21b, and covers it as the porous material 21b. At this time, if a sheet 21a is arranged on a portion of the porous material 21b, both the sheet 21a and the porous material 21b can simultaneously cover the outer periphery of the wound body R. In this case, since the permeate flow path material 3 is sealed together with the separation membrane 1 during the formation of the membrane L, the supply liquid 7 flows in the permeate flow path material 3 and does not mix with the permeate liquid 8.

[0086] It should be noted that it is also possible to do as follows: Figure 5DAs shown, when winding the through-flow path material 3 that extends to the center tube 5 and the outer periphery, sheet 21a and porous material 21b are pre-layered, and sheet 21a and porous material 21b are simultaneously covered on the outer periphery of the wound body R.

[0087] In addition, it can be like Figure 8A As shown, the outer layer covering flow path material 21 is composed of a laminate containing sheet 21a, porous material 21b, and sheet 21a. That is, sheet 21a can be provided as the outermost layer of the outer layer covering flow path material 21. However, since porous material 21b generally has high buffering capacity, it is preferable to provide porous material 21b as the outermost layer of the outer layer covering flow path material 21 to ensure that the outer layer covering flow path material 21 is tightly sealed to the inner surface of the pressure vessel 30.

[0088] On the other hand, it can also be like Figure 8B As shown, a textured sheet 21s is provided on the outer and / or inner surfaces instead of the porous material 21b, or a textured sheet 21s is provided on the outer and / or inner surfaces in addition to the porous material 21b. Examples of textured shapes include grooves, ribs, dots, irregular patterns, and embossing. By providing the textured sheet 21s, flow paths can be formed using the surface texture. Pressure loss can then be adjusted by the shape, width, height, and spacing of the textures.

[0089] The embossed sheet 21s is preferably a sheet obtained by embossing a sheet. Alternatively, the desired pressure loss can be adjusted by winding the embossed sheet into multiple layers. In addition to being cost-effective, the processability and the constraint force during winding also become appropriate when using embossed sheets.

[0090] It should be noted that, Figure 8C The example shown is an outer layer covering flow path material 21 obtained by combining a textured sheet 21s and a porous material 21b. Various combinations can be made in this invention.

[0091] (Supply-side flow path materials)

[0092] The supply-side flow path material 2 generally serves to ensure a gap for uniformly supplying fluid to the membrane surface. Such a supply-side flow path material 2 can be made of materials such as mesh, woven fabric, or textured sheets, and a maximum thickness of approximately 0.1 mm to approximately 3 mm can be used as needed. In such a supply-side flow path material 2, materials with low pressure loss are preferred, and materials that generate a moderate turbulence effect are more preferred. Furthermore, flow path materials are disposed on both sides of the separation membrane 1, but typically different flow path materials are used for the supply-side flow path material 2 on the supply liquid side and the permeate-side flow path material 3 on the permeate side. Preferably, a coarse and thick mesh flow path material is used in the supply-side flow path material 2, while a fine mesh textile or woven flow path material is used in the permeate-side flow path material 3.

[0093] In applications such as seawater desalination and wastewater treatment, when using RO or NF membranes, the supply-side flow path material 2 is disposed on the inner surface of the aforementioned folded composite semi-permeable membrane. The structure of the supply-side flow path material 2 is generally preferably a mesh structure in which linear elements are arranged in a lattice pattern.

[0094] There are no particular limitations on the materials used to constitute the supply-side flow path material 2; polyethylene, polypropylene, etc., can be used. These resins may contain bactericides and antibacterial agents. The thickness of the supply-side flow path material 2 is generally 0.2 mm to 2.0 mm, preferably 0.5 mm to 1.0 mm. When the thickness of the supply-side flow path material 2 is too thick, the permeation rate and the amount of membrane that can be accommodated in the membrane element decrease together. Conversely, when the thickness of the supply-side flow path material 2 is too thin, contaminants are easily adsorbed, thus easily leading to deterioration of permeation performance.

[0095] In particular, in this invention, by combining it with the supply-side flow path material 2 of 0.6 mm to 1.0 mm, pollutants are less likely to accumulate and bioaccumulation is less likely to occur, thus suppressing the decrease in flux even during continuous use.

[0096] (Central Management)

[0097] The central tube 5 only needs to have openings 5a around its perimeter; any conventional central tube can be used. In applications such as seawater desalination and wastewater treatment, the permeate water after passing through the separation membrane 1 enters the central tube 5 through the openings in the wall, forming a permeate-side flow path. The length of the central tube 5 is generally longer than the axial length of the wound body R, but a central tube 5 with a connecting structure, such as being divided into multiple sections, can be used. There are no particular restrictions on the material used to construct the central tube 5; thermosetting resin or thermoplastic resin can be used.

[0098] That is, the center tube 5 can be any of the following: extending only downstream of the winding body R, extending to both upstream and downstream of the winding body R, or extending only upstream of the winding body R. However, when the winding body R has a detachable anti-stretch material 25 on its downstream side, it is preferable that the center tube 5 extends at least downstream of the winding body R.

[0099] exist Figure 1 In the example of membrane element E shown, the central tube 5 protrudes upstream and downstream with substantially the same length relative to the wound body R, but as in... Figure 7A When the central tube 5 extends only downstream of the winding body R, the peripheral components used in the conventional structure can be shared, which is therefore more preferable.

[0100] (Through sideflow material)

[0101] In applications such as seawater desalination and wastewater treatment, when using RO membranes and NF membranes, such as Figure 3 As shown, the permeate flow path material 3 is arranged in a manner sandwiched between opposing separation membranes 1 within the membrane sheet L. For this permeate flow path material, it is required to support the pressure applied to the membrane from the back of the membrane and ensure the flow path of the permeate.

[0102] In this invention, to ensure such functionality, it is preferable to use warp-knitted fabric to form a transmissive side flow path material, and more preferably a warp-knitted fabric that has undergone resin reinforcement or fusion treatment after the knitting process.

[0103] Examples of filaments that can be used as components of the transmissive side flow path material include polyesters such as polyethylene terephthalate and polyethylene naphthalate; and polyolefins such as polyethylene and polypropylene. Among these, polyethylene terephthalate is particularly preferred from the viewpoint of processability and production.

[0104] When resin reinforcement is applied after the woven fabric is formed, methods such as impregnating the fibers with resin and then curing it, or coating the fiber surface with resin and then curing it, can be cited. Examples of resins used for reinforcement include melamine resin and epoxy resin.

[0105] The constituent yarns of the side flow path material can be monofilaments or multifilaments, and warp-knitted fabrics are formed using constituent yarns of a certain thickness. Among warp-knitted fabrics, semi-knitted fabrics with a clear structure of straight, continuous grooves and double-comb warp plain knitted fabrics are preferred.

[0106] The thickness of the permeate flow path material is preferably 0.10 mm to 0.40 mm, more preferably 0.15 mm to 0.35 mm, and even more preferably 0.20 mm to 0.30 mm. When the thickness of the permeate flow path material is 0.10 mm or more, sufficient flow path can be ensured, and the pressure loss of the permeate can be reduced. In addition, when the thickness of the permeate flow path material is 0.40 mm or less, the effective membrane area of ​​the separation membrane in the membrane element increases, making it easier to increase the flow rate of the permeate. From the perspective of the warp-knitted fabric forming the above-mentioned thickness, the constituent yarn of the permeate flow path material is preferably 0.1 mm to 0.15 mm.

[0107] In this invention, the width of the continuous, linear grooves in the warp-knitted fabric is preferably 0.05 mm to 0.40 mm, more preferably 0.10 mm to 0.28 mm. When the groove width is less than 0.05 mm, there is a tendency for the pressure loss of the permeable liquid to become too large. When the groove width is greater than 0.40 mm, it can sometimes easily cause a decrease in the rejection rate due to the deformation of the composite semipermeable membrane.

[0108] It should be noted that the width of a continuous, straight groove in a warp-knitted fabric refers to the average of the widest and narrowest intervals between adjacent loops. This average can be determined by measuring 10 loop pairs using microscopic photographs and then averaging these 10 averages to calculate the width of the continuous groove.

[0109] The direction in which the permeate flow path material is arranged in the membrane element can be any direction, but it is preferred to be wound in the circumferential direction in the direction of a straight continuous groove.

[0110] (Separation membrane)

[0111] Various porous membranes can be used as the separation membrane 1, but a composite semi-permeable membrane having a separation functional layer on the surface of the porous support is preferred. As the porous support, a porous support having a polymer porous layer on one side of the nonwoven fabric layer is preferred. The thickness of the separation membrane, particularly the composite semi-permeable membrane, is preferably about 70 μm to about 160 μm, more preferably 85 μm to 130 μm.

[0112] Such composite semi-permeable membranes are called RO (reverse osmosis) membranes, NF (nanofiltration) membranes, and FO (forward osmosis) membranes according to their filtration performance and treatment methods. They can be used for ultrapure water production, seawater desalination, brine desalination, and wastewater reuse.

[0113] Examples of separation functional layers include polyamide, cellulose, polyether, and silicon-containing layers, with polyamide-based separation functional layers being preferred. Polyamide-based separation functional layers are generally homogeneous membranes without visually perceptible pores and possess the desired ion separation capability. There are no particular limitations on this separation functional layer, as long as it is a polyamide film that is not easily peeled off from the porous polymer layer. For example, polyamide-based separation functional layers formed by interfacial polymerization of polyfunctional amine components and polyfunctional acyl halide components on a porous support membrane are well-known.

[0114] There are no particular limitations on the method for forming the aforementioned polyamide-based separation functional layer on the surface of the polymer porous layer; all known methods can be used. Examples include interfacial polymerization, phase separation, and thin-film coating. Interfacial polymerization is particularly preferred in this invention. An example of interfacial polymerization is as follows: an aqueous amine solution containing a polyfunctional amine component is coated onto the polymer porous layer, and then interfacial polymerization occurs by contacting the amine aqueous solution coating with an organic solution containing a polyfunctional acyl halide component, thereby forming the surface layer.

[0115] The polyfunctional amine component contained in the above-mentioned aqueous amine solution is a polyfunctional amine having two or more reactive amino groups, and examples include aromatic, aliphatic, and alicyclic polyfunctional amines. Examples of aromatic polyfunctional amines include: m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 1,3,5-triaminobenzene, 1,2,4-triaminobenzene, 3,5-diaminobenzoic acid, 2,4-diaminotoluene, 2,6-diaminotoluene, N,N'-dimethylm-phenylenediamine, 2,4-diaminoanisole, diaminophenol, and phenylenediamine. Examples of aliphatic polyfunctional amines include: ethylenediamine, propylenediamine, tris(2-aminoethyl)amine, and N-phenylethylenediamine. Examples of the aforementioned alicyclic polyfunctional amines include 1,3-diaminocyclohexane, 1,2-diaminocyclohexane, 1,4-diaminocyclohexane, piperazine, 2,5-dimethylpiperazine, and 4-aminomethylpiperazine. One or more of these polyfunctional amines may be used. Particularly in this invention, when a high rejection rate is required for reverse osmosis membrane performance, m-phenylenediamine, which provides a highly dense separation functional layer, is preferably used as the main component. Furthermore, when a high flux retention rate is required for NF membrane performance, piperazine is preferably used as the main component.

[0116] The polyfunctional acyl halides contained in the above-mentioned organic solutions are polyfunctional acyl halides having two or more reactive carbonyl groups, and can be categorized as aromatic, aliphatic, and alicyclic polyfunctional acyl halides. Examples of aromatic polyfunctional acyl halides include: pyromellitic trimethylbenzene chloride, terephthaloyl chloride, isophthaloyl chloride, biphenyl dimethylbenzene chloride, naphthyl dimethylbenzene chloride, benzenetrisulfonyl chloride, benzenedisulfonyl chloride, chlorosulfonyl terephthaloyl chloride, etc. Examples of aliphatic polyfunctional acyl halides include: malonyl chloride, succinicotinic chloride, glutaryl chloride, trimethylolpropionate chloride, succinicotinic chloride, glutaryl chloride, glutaryl halide, adipyl halide, etc. Examples of alicyclic polyfunctional acyl halides include cyclopropane triacyl chloride, cyclobutane tetraacyl chloride, cyclopentane triacyl chloride, cyclopentane tetraacyl chloride, cyclohexane triacyl chloride, tetrahydrofuran tetraacyl chloride, cyclopentane diacyl chloride, cyclobutane diacyl chloride, cyclohexane diacyl chloride, and tetrahydrofuran diacyl chloride. One or more of these polyfunctional acyl halides can be used. For obtaining a surface layer with high salt-barrier properties, aromatic polyfunctional acyl halides are preferred. Furthermore, it is preferable to use a polyfunctional acyl halide with three or more nucleotides in at least a portion of the polyfunctional acyl halide component to form a cross-linked structure.

[0117] As for organic solvents containing the aforementioned polyfunctional acyl halides, there are no particular limitations as long as they have low solubility in water, do not degrade the porous support membrane, and can dissolve the polyfunctional acyl halides. Examples include saturated hydrocarbons such as cyclohexane, heptane, octane, and nonane; and halogenated hydrocarbons such as 1,1,2-trichlorotrifluoroethane. Saturated hydrocarbons with a boiling point of 300°C or lower are preferred, and those with a boiling point of 200°C or lower are even more preferred.

[0118] Additives can be added to the aforementioned amine aqueous solutions and organic solutions to improve various properties and processability. Examples of such additives include: polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylic acid; polyols such as sorbitol and glycerol; surfactants such as sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, and sodium lauryl sulfate; alkaline compounds such as sodium hydroxide, trisodium phosphate, and triethylamine to remove hydrogen halides generated during polymerization; acylation catalysts; and a solubility parameter of 8 (cal / cm³) as described in Japanese Patent Application Publication No. 8-224452. 3 ) 1 / 2 ~14 (cal / cm) 3 ) 1 / 2 Compounds, etc.

[0119] A coating containing various polymer components can be applied to the exposed surface of the aforementioned separation functional layer. There are no particular limitations on the polymer components, as long as they are polymers that do not dissolve the separation functional layer and the porous support membrane and do not leach out during water treatment operations. Examples include: polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropyl cellulose, polyethylene glycol, and saponified polyethylene-vinyl acetate copolymer. Polyvinyl alcohol is preferred, and it is particularly preferred to use polyvinyl alcohol with a saponification degree of 99% or higher, or to crosslink polyvinyl alcohol with a saponification degree of 90% or higher with the aforementioned surface polyamide resin to form a structure that is not easily dissolved during water treatment. By applying such a coating, the charge state of the membrane surface can be adjusted, and hydrophilicity can be imparted, thus inhibiting the adhesion of pollutants. Furthermore, through synergistic effects with the present invention, the flux retention effect can be further improved.

[0120] As for the nonwoven fabric layer used in this invention, there are no particular limitations as long as it provides adequate mechanical strength while maintaining the separation and permeability properties of the aforementioned composite semi-permeable membrane; commercially available nonwoven fabrics can be used. For example, materials containing polyolefins, polyesters, cellulose, etc., or materials composed of a mixture of multiple raw materials can be used. Polyester is preferred, especially from the perspective of formability. Furthermore, long-fiber nonwoven fabrics and short-fiber nonwoven fabrics can be used appropriately, but from the viewpoint of preventing micro-fuzzing that leads to pinhole defects and ensuring the uniformity of the membrane surface, long-fiber nonwoven fabrics are preferred.

[0121] As for the aforementioned polymer porous layer, there are no particular limitations as long as it is a porous layer capable of forming the aforementioned polyamide-based separation functional layer; it is typically a microporous layer with a pore size of about 0.01 μm to about 0.4 μm. Examples of materials that can form the aforementioned microporous layer include polysulfone, polyarylene ether sulfone (exemplified in polyether sulfone), polyimide, polyvinylidene fluoride, and various other materials. Particularly from the viewpoint of chemical stability, mechanical stability, and thermal stability, it is preferable to form a polymer porous layer using polysulfone or polyarylene ether sulfone.

[0122] (Extremely stretchable material)

[0123] In this invention, such as Figure 1 As shown, it is preferable to place the anti-stretch material 25 on the downstream side of the winding body R, and it is preferable to provide a detachable anti-stretch material 25.

[0124] As the anti-stretch material 25, it preferably has at least an outer peripheral side baffle 29 disposed on the downstream side near the outer periphery of the winding body R, and more preferably, as shown in the figure. Figure 4The device is provided with an outer peripheral side baffle 29 disposed on the downstream side near the outer periphery of the winding body R and an inner peripheral side baffle 27 disposed on the downstream side near the inner periphery of the winding body R. Here, "near the inner periphery of the winding body R" refers to any position within the range of 0% to 30% from the inner periphery when the distance between the outer periphery and the inner periphery of the winding body R is set to 100%, and "near the outer periphery" refers to any position within the range of 70% or more from the inner periphery.

[0125] It should be noted that the outer diameter of the outer peripheral baffle 29 can be larger than the outer diameter of the wound body R, preferably 98% to 100.0% relative to the inner diameter of the pressure vessel 30, more preferably 99% to 100.0%, and most preferably 100.0%. By adopting such an outer diameter of the outer peripheral baffle 29, the low-concentration concentrate flowing inside or outside the porous material 21b can be more effectively mixed and stirred, and supplied to the next stage.

[0126] The anti-stretching material 25 of this embodiment is shown as follows. Figure 4 The example shown has an annular portion 26 and ribs 28 extending radially from the annular portion. There is no particular limitation on the number of ribs 28, but from the viewpoint of ensuring sufficient flow path and strength while suppressing expansion and contraction, 4 to 20 ribs are preferred, and 8 to 16 ribs are more preferred.

[0127] The anti-stretch member 25 is preferably detachably mounted on the central tube 5 extending downstream of the wound body R. Therefore, the annular portion 26 has an inner circumferential surface into which the central tube 5 can be inserted. The rib 28, by contacting the downstream end face of the wound body R with its upstream end face, is able to suppress the stretching deformation of the wound body R.

[0128] The reasons for preferably providing an outer peripheral baffle 29 and an inner peripheral baffle 27 on the anti-stretch material 25 are explained in detail.

[0129] There is a concentration distribution in the concentrate flowing out of membrane element E. There are two reasons for this uneven concentration. One reason is that, within each membrane piece L, the flux is higher closer to the central tube 5 and lower closer to the membrane tip. As the feed solution 7 flows along the axial direction A1 in the feed-side flow path within membrane element E, the feed solution 7 is more concentrated closer to the central tube 5, resulting in a higher concentration. Another reason is that portions that do not permeate are not concentrated, thus maintaining a lower concentration compared to portions that permeate and become more concentrated. The non-permeable portions refer to the protective strip adhered to the inside of the creases of the separation membrane 1 to protect it, and the portions at the membrane tips coated with adhesive.

[0130] The concentration distribution of the concentrate exiting membrane element E, particularly the low-concentration portion corresponding to the latter part, warrants further investigation in discussing the overall filtration efficiency of the membrane module. This latter part corresponds to the membrane folds and membrane ends; in terms of the outlet cross-section of membrane element E, it is the portion near the central tube 5 and the portion near the opposite outer periphery. The concentrate 9 exiting from these portions has a lower concentration compared to other portions, and when flowing into the next stage membrane element E with the same distribution, it is highly likely to flow through the central zone and membrane ends as in the previous stage. Low concentration refers to low osmotic pressure; while a high flux of feed liquid 7 can be expected simply by allowing it to flow across the membrane surface, there is no efficiency when it flows through portions that are not filtered by the membrane.

[0131] As a countermeasure, baffle structures are installed on the anti-stretch material 25 in the two sections with low concentrations to allow the supply liquid 7 to flow in a detour. The eddies generated by the backflow when passing through the detour baffles stir and mix the low-concentration and high-concentration sections, thereby improving the overall filtration performance of the membrane module.

[0132] It should be noted that since the supply liquid 7 flowing through the porous material 21b layer is not filtered through a membrane, the concentration remains low. This is achieved by utilizing a baffle structure on the outer periphery to detour the flow, allowing for mixing with the higher concentration portion.

[0133] (Other embodiments of anti-stretch materials)

[0134] The preceding embodiments show an example with an annular portion 26 and ribs 28 extending radially from the annular portion, but it is also possible to have... Figure 6A As shown, the annular portion 26 is omitted because the inner circumferential side of the rib 28 contacts the central tube 5.

[0135] Alternatively, it can be like Figure 6B As shown, an outer peripheral side baffle 29 disposed on the downstream side near the outer periphery of the winding body R and an inner peripheral side baffle 27 disposed on the downstream side near the inner periphery of the winding body R are formed by continuous plate-shaped portions, and multiple openings are provided on the plate-shaped portions.

[0136] In addition, it can also be like Figure 6C As shown, the inner peripheral baffle 27 is omitted, or a sealing material (e.g., an O-ring) is provided on the outer periphery of the outer peripheral baffle 29, so that the outer periphery of the anti-stretch material 25 is sealed to the inner surface of the pressure vessel.

[0137] It should be noted that, in order to enable the interconnect 35 to function as an anti-stretch material 25, the interconnect 35 can be integrated with the anti-stretch material 25. For example, it can be adopted as follows: Figure 7BThe structure shown has an inner peripheral baffle 27 provided around the interconnector 35 instead of an annular portion 26, the inner peripheral end of the rib 28 is positioned near the outer periphery of the central tube 5, and an outer peripheral baffle 29 is provided across the rib 28.

[0138] (Other embodiments of spiral membrane elements)

[0139] The most suitable embodiment of the present invention has been described in the foregoing description. However, the present invention is not limited to this embodiment, and various modifications can be made within the scope of the technical concept substantially the same as that described in the claims of the present invention.

[0140] That is, in the above embodiments, such as Figures 2A to 2C As shown, an example has been described where a separating membrane 1 folded in half with the supply-side flow path material 2 sandwiched in the middle is overlapped with a permeable-side flow path material 3 and adhesives 4 and 6 are applied. However, in this invention, a folded separating membrane 1 can also be overlapped on the permeable-side flow path material 3 and adhesives 4 and 6 can be applied thereon. Alternatively, instead of a folded separating membrane 1, two separating membranes 1 can be used to sandwich the supply-side flow path material 2 in the middle, and a sealing portion can also be provided on the winding start side. Furthermore, a continuous separating membrane 1 can be used, eliminating the need for an outer peripheral sealing portion 12.

[0141] (Spiral membrane module)

[0142] like Figure 1 As shown, the spiral membrane module of the present invention is characterized by comprising a spiral membrane element E as described above and a pressure vessel 30 for housing the spiral membrane element E, and the outer diameter, based on the outer periphery of the outer covering material, is 99% to 100% of the inner diameter of the pressure vessel 30. All conventional pressure vessels used to house the membrane element E can be used as the pressure vessel 30.

[0143] In the illustrated example, pressure vessel 30 has an outer cylinder member 31, a downstream end plate member 32 and an upstream end plate member 34, and the end plate members 32 and 34 are liquid-tightly held on the outer cylinder member 31 by a retaining ring 33.

[0144] Furthermore, the membrane elements E are connected to each other by interconnectors 35, and the upstream side of the central tube 5 of the upstream membrane element E is closed by a cover 37. The downstream side of the central tube 5 of the downstream membrane element E is connected to the opening of the downstream end plate member 32 via an adapter 36, forming a structure that allows the permeate 8 to be discharged. An opening for discharging concentrate 9 is also provided on the downstream end plate member 32, and an opening for supplying feed liquid 7 is provided on the upstream end plate member 34.

[0145] In the example shown, it is set with Figure 4The anti-stretch material 25 shown, and the peripheral side baffle 29 disposed on the downstream side near the outer periphery of the winding body R, are shaped such that their outer periphery contacts the inner surface of the pressure vessel 30. This minimizes the amount of concentrated liquid 9 flowing in the gap between the peripheral side baffle 29 and the inner surface of the pressure vessel 30, thereby further improving the stirring and mixing effect.

[0146] The materials, structure, manufacturing method, and anti-stretch material 25 of each component of the spiral membrane element E are as described above.

[0147] Industrial practicality

[0148] According to the present invention, the disposal of used membrane elements can be carried out efficiently. Since the outer layer of the membrane element does not require glass fiber, no glass residue remains in the incineration ash even after incineration, making the disposal of incineration ash easy.

[0149] When used membrane elements are used as heat recovery materials, they can be processed into RPF (refusepaper and plastic fuel). RPF manufactured using waste elements can also be appropriately used in paper mills. During RPF manufacturing, there is less mechanical wear during crushing and less damage to the crusher.

[0150] The structure allows for repeated use of the anti-stretch material due to its removable and repositionable design, and the number of units required can be reduced as it is only installed on the downstream side. The cost of U-shaped seals can be reduced by eliminating the need for them. Furthermore, the membrane area of ​​each membrane element can be increased by expanding the outer diameter and axial length of the winding body, thereby increasing the throughput of the treated liquid.

[0151] Label Explanation

[0152] 1: Separation membrane

[0153] 2: Supply-side flow path materials

[0154] 3: Through side flow path material

[0155] 5: Central tube

[0156] 7: Supply fluid

[0157] 8: Permeable liquid

[0158] 9: Concentrate

[0159] 21: Outer layer covering flow path material

[0160] 21a: Sheet

[0161] 21b: Porous materials

[0162] 21s: Concave-convex sheet

[0163] 25: Anti-stretching materials

[0164] 27: Inner peripheral side baffle

[0165] 29: Outer peripheral baffle

[0166] 30: Pressure Vessel

[0167] A1: Axial direction

[0168] E: Spiral membrane element

[0169] R: Wrapped body

Claims

1. A spiral membrane element, wherein, The spiral membrane element has a perforated central tube, a wound body wound around the central tube and comprising a separation membrane, a supply-side flow path material, and a permeation-side flow path material, and an outer covering material disposed on the outer periphery of the wound body, wherein... The outer covering material includes an outer covering flow path material, which, while covering the outer periphery of the wound body to block the inflow of the supply liquid, forms flow paths on the outside of the wound body. The outer layer covering flow path material comprises a sheet covering the outer periphery of the wound body and a porous material covering the sheet. When used in a pressure vessel, the outer diameter, based on the outer periphery of the outer covering material, is 99% to 100% of the inner diameter of the pressure vessel.

2. The spiral membrane element as described in claim 1, wherein, The downstream side of the winding body has a removable anti-stretch material.

3. The spiral membrane element as described in claim 2, wherein, The anti-stretch material is provided with an outer peripheral side baffle disposed on the downstream side of the outer periphery of the winding body and an inner peripheral side baffle disposed on the downstream side of the inner periphery of the winding body.

4. The spiral membrane element as described in claim 2 or 3, wherein, The anti-stretch material is installed on the central tube extending downstream of the winding body.

5. A spiral membrane module, wherein, The spiral membrane module comprises a spiral membrane element as described in any one of claims 1 to 4 and a pressure vessel housing the spiral membrane element, and The outer diameter, based on the outer perimeter of the outer covering material, is 99% to 100% of the inner diameter of the pressure vessel.

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