JP4222243B2 - Spiral membrane element - Google Patents

Description

  The present invention relates to a spiral membrane element that separates components suspended and dissolved in a liquid. More specifically, the present invention relates to a backwash operation for recovering a filtration flow rate (permeating filtered water or the like from a permeation side to a separation membrane). This relates to a spiral membrane element having high durability against

  Conventionally, as a fluid separation element used for reverse osmosis filtration, ultrafiltration, microfiltration, etc., for example, a supply-side channel material that guides the supply-side fluid to the surface of the separation membrane, a separation membrane that separates the supply-side fluid, and a separation membrane A spiral type fluid separation element is known in which a unit comprising a permeate-side flow channel material that permeates the permeated fluid separated from the supply-side fluid and guides it to the central tube is wound around the perforated central tube.

  As shown in FIGS. 3 (a) to 3 (c), such a spiral membrane element generally has a structure in which a supply-side flow path material 2 is disposed between two folded separation membranes 1, and a permeation side. The separation membrane unit U is manufactured by stacking the flow path material 3 and applying adhesives 4 and 6 to the periphery (three sides) of the separation membrane to form a sealing portion that prevents mixing of the supply side fluid and the permeation side fluid. The unit U is manufactured by winding one or more units U around the central tube 5 in a spiral shape and further sealing the periphery of the separation membrane.

  As a result, as shown in the side view of the main part of FIG. 4A, both ends of the separation membrane 1 facing each other through the permeate-side flow path member 3 are sealed by both-end sealing portions 11 and arranged in a spiral shape. In addition, the supply-side flow path member 2 is interposed between the plurality of both-end sealing portions 11. Moreover, as shown in the longitudinal cross-sectional view of the main part of FIG. 4B, the outer peripheral side end of the separation membrane 1 that faces through the permeate-side flow path member 3 is the outer peripheral sealing portion 12 along the axial direction. The supply-side flow path material 2 is interposed between the adjacent separation membranes 1 that are sealed by and arranged in a spiral shape.

  When the separation membrane unit U is manufactured, the relationship between the winding length of the conventional supply-side flow path member 2 and the winding length of the unit U is the same length or the length of the supply-side flow path member 2 is the unit. It was a little shorter than the length of U (for example, refer patent document 1).

  For this reason, as shown in FIG.4 (b), the inner peripheral side end 12a of the outer peripheral side sealing part 12 is arrange | positioned from the outer peripheral side end 2a of the supply side flow path material 2 arrange | positioned inside the inner peripheral side. It had been. In addition, the vicinity of the outer peripheral side sealing portion 12 and the outer peripheral side end 2a of the supply side flow path member 2 is constrained by the exterior material 15 and has a structure in which the diameter does not expand. In this specification, the winding start side along the spiral shape is referred to as “inner circumference side”, and the winding end side is referred to as “outer circumference side”.

By the way, in the spiral membrane element as described above, a backwash operation for removing the deposition of separated components and recovering the filtration flow rate may be performed. There was a problem that the separation membrane 1 on the inner peripheral side of the plate was damaged. Specifically, when the separation membrane 1 reinforced with a nonwoven fabric was used on the back side of the separation active layer, the separation membrane layer often peeled from the nonwoven fabric.
JP-A-4-326926

  Therefore, an object of the present invention is to provide a spiral membrane element in which the separation membrane is not easily damaged in the vicinity of the outer peripheral side sealing portion even when the backwash operation is performed over a long period of time.

  The inventors of the present invention have made various studies on the cause of the damage of the separation membrane in the vicinity of the outer peripheral sealing portion. It occurs at the position where the supply-side flow path material is disposed and the outer peripheral side sealing portion is disposed outside the supply-side flow path material, and the supply side flow material is disposed between the separation membrane and the outer peripheral side sealing portion. It has been found that a simple improvement of preventing the passage material from intervening can effectively prevent the separation membrane from being damaged, and the present invention has been completed.

  That is, in the spiral membrane element of the present invention, the separation membrane, the supply-side channel material, and the permeate-side channel material are spirally wound around the perforated central tube in a laminated state, and the outer peripheral surface is restrained. In the spiral membrane element provided with a cylindrical wound body and provided with a sealing portion for preventing the mixing of the supply side fluid and the permeate side fluid, the separation membrane that faces the permeation side flow path member Has an outer peripheral side sealing portion along the axial direction at the outer peripheral side end portion, and the outer peripheral side end of the supply side flow path material is arranged further on the inner peripheral side than the inner peripheral side end of the outer peripheral side sealing portion. It is characterized by that.

  The effects of the spiral membrane element of the present invention are as follows. In the spiral membrane element, the separation membrane adjacent to the supply-side channel material is supplied with filtrate from the permeate-side channel material side during the backwash operation, and the separation membrane (that is, the separation membrane leaf) expands on the supply side. . At that time, the separation membranes facing each other through the supply-side channel material swell to the same extent, so that the separation membrane presses the supply-side channel material, and the bulge is half the thickness of the supply channel material. Become. However, the separation membrane facing the outer peripheral side sealing portion via the supply-side channel material swells during backwashing, but the outer peripheral side sealing portion does not expand, and the separation membrane swells at that position. The supply channel material thickness is maximized. For this reason, the separation membrane at this position is more likely to be damaged than other parts. Therefore, as in the present invention, the outer peripheral side end of the supply-side flow path member is disposed further on the inner peripheral side than the inner peripheral side end of the outer peripheral side sealing portion, thereby being arranged inside the outer peripheral side sealing portion. Since the separation membrane is restrained from bulging by the outer peripheral side sealing portion, the separation membrane is hardly damaged at that position. As a result, it is possible to provide a spiral membrane element in which the separation membrane is not easily damaged in the vicinity of the outer peripheral side sealing portion even when the backwash operation is performed for a long period of time.

  In the above, it is preferable that the said outer peripheral side sealing part is contacting the inner side separation membrane or the inner outer peripheral side sealing part through the supply direction flow-path material over the full width of a circumferential direction. In this case, since the outer peripheral side sealing portion restrains the swelling of the separation membrane over the entire width in the circumferential direction without using the supply-side flow path material, it is possible to more reliably prevent the separation membrane from being damaged as described above.

  In addition, the present invention is particularly effective when the separation membrane is reinforced with a nonwoven fabric on the back side of the separation active layer, and the separation active layer is disposed on the supply-side channel material side. . That is, when such a separation membrane is used, the separation membrane layer is easily peeled off from the nonwoven fabric particularly in the vicinity of the outer peripheral side sealing portion, and therefore the present invention having the above-described effects is particularly effective.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of a method for producing a spiral membrane element of the present invention. 2A and 2B are main part views showing an example of the spiral membrane element of the present invention. FIG. 2A is a side view of the main part, and FIG. 2B is a longitudinal sectional view of the main part.

  As shown in FIGS. 1 to 2, the spiral membrane element of the present invention includes a separation membrane 1, a supply-side channel material 2, and a permeate-side channel material 3 around a perforated central tube 5 in a laminated state. And a cylindrical wound body R wound in a spiral shape and whose outer peripheral surface is constrained, and a sealing portion for preventing mixing of the supply side fluid and the permeation side fluid. The sealing portion includes a both-end sealing portion 11 and an outer peripheral side sealing portion 12.

  As shown in FIG. 2A, both ends of the separation membrane 1 facing each other through the permeate-side flow path member 3 are sealed by both-end sealing portions 11, and a plurality of both-end sealing portions 11 arranged in a spiral shape. Between them, the supply-side channel material 2 is interposed. Further, as shown in FIG. 2B, the outer peripheral side end of the separation membrane 1 facing through the permeation side flow path member 3 is sealed by an outer peripheral side sealing portion 12 along the axial direction, and spiral. Between the adjacent separation membranes 1 arranged in a shape, a supply-side channel material 2 is interposed.

  Moreover, as shown in FIG.2 (b), the inner peripheral side end 12a of the outer peripheral side sealing part 12 is arrange | positioned from the outer peripheral side end 2a of the supply side flow path material 2 arrange | positioned inside the outer peripheral side. Yes. At this time, since the supply-side flow path material 2 is not interposed between the outer peripheral side sealing portion 12 and the separation membrane 1 disposed on the inner side, the backwashing operation is performed for a long time due to the above reason. However, it is possible to make it difficult to damage the separation membrane 1 in the vicinity of the outer peripheral side sealing portion 12. For this reason, it is preferable that the outer peripheral side sealing portion 12 is in contact with the inner separation membrane 1 or the inner outer peripheral side sealing portion 12 without passing through the supply-side flow path member 2 over the entire circumferential width. Moreover, the outer peripheral side sealing part 12 has a structure which is restrained by the exterior material 15 and does not expand in diameter.

  Said cylindrical winding body R can be manufactured by the manufacturing process shown, for example in FIG. 1A is a plan view of the separation membrane unit U, FIG. 1B is a front view of the separation membrane unit U, and FIG. 1C shows a state before the separation membrane unit U is stacked and wound. FIG.

  First, as shown in FIGS. 1A to 1B, the supply side flow path member 3 and the permeate side flow path member 3 are stacked while the separation membrane 1 is folded in half, and the supply fluid and Adhesives 4 and 6 or adhesive sheets for forming the sealing portions 11 and 12 for preventing the permeation of the permeated fluid were applied or arranged on both end portions in the axial direction and the winding end portion of the permeate side flow path material 3. A separation membrane unit U is prepared. At this time, a protective tape may be attached to the fold portion of the separation membrane 1.

In the present invention, in order to dispose the inner peripheral side end 12a of the outer peripheral side sealing portion 12 on the outer peripheral side of the outer peripheral side end 2a of the supply side flow path member 2 disposed on the inner side, the separation membrane as described above When the unit U is manufactured, it is only necessary to shorten the length of the supply-side channel material 2 (position of the winding end portion). That is, the position of the winding end portion of the supply-side channel material 2 is arranged on the winding start side from the inner peripheral side end 12a of the outer peripheral side sealing portion 12 formed on the separation membrane 1 arranged on the upper surface thereof. . Specifically, for example, in an 8-inch spiral element, the winding end of the supply-side flow path member 2 is arranged on the winding start side by 100 to 120 mm from the inner peripheral side end 12a of the outer peripheral side sealing portion 12. preferable. At this time,
Inner length = length of sealing part in the circumferential direction + (element outer circumference length / number of laminated leaves)
Can be calculated with

  Or it is preferable to arrange | position the winding termination | terminus of the supply side flow-path material 2 to the winding start side by the stacking pitch of the separation membrane unit U from the inner peripheral side end 12a of the outer peripheral side sealing part 12. FIG. In addition, the circumferential width of the outer peripheral side sealing portion 12 can be appropriately determined in consideration of the sealing performance and the effective membrane area.

  In the present embodiment, the example has been described in which the permeation-side channel material 3 is stacked on the separation membrane 1 folded in half so as to sandwich the supply-side channel material 2 and the adhesives 4 and 6 are applied. It is also possible to apply the adhesives 4 and 6 on the separation membrane 1 folded in two on the permeate-side channel material 3. Further, instead of the bifurcated separation membrane 1, two separation membranes 1 may be used to sandwich the supply-side flow path material 2 and a sealing portion may be provided also on the winding start side.

  As the separation membrane 1, a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, or the like can be used. The present invention is particularly effective when the separation membrane 1 is reinforced with a nonwoven fabric on the back side of the separation active layer. Specific examples include reverse osmosis membranes, ultrafiltration membranes, and microfiltration membranes formed by applying a film-forming solution of various polymers on the surface of a nonwoven fabric as a base material and using a phase separation method or the like. In such a separation membrane 1, the separation active layer is generally disposed on the supply-side channel material 2 side.

  For the supply-side channel material 2, a net-like material (including a ladder shape and a rhombus shape), a corrugated plate, and the like can be used. In the present invention, the supply-side channel material 2 is a ladder-type net-like channel material. In this case, it is possible to effectively prevent the separation membrane 1 from being damaged in the vicinity of the outer peripheral side sealing portion 12. A net-like or knitted material or the like can be used for the permeate-side channel material 3.

  As the adhesives 4 and 6, any conventionally known adhesives such as urethane adhesives, epoxy adhesives and hot melt adhesives can be used. Moreover, the sealing parts 11 and 12 can be formed using a hot-melt adhesive, a heat-fusing adhesive tape, a heat-fusing sheet, or the like, in addition to being formed with an adhesive.

  In the present invention, it is possible to prevent the horizontal flow by sealing the porous layer gap in the adhesive-coated portion of the separation membrane 1 in advance, and improve the sealing performance of the sealing portions 11 and 12. As a method for previously sealing the porous layer voids according to the present invention, there are methods such as filling the porous layer with an adhesive, crushing the porous layer with pressure, and melting the porous layer with heat.

  Next, as shown in FIG. 1 (c), a plurality of the separation membrane units U are stacked and wound around the perforated center tube 5 in a spiral shape, and then the adhesives 4, 6 and the like are heated. The cylindrical wound body R is obtained by curing or the like. At that time, the periphery of the central tube 5 may be sealed at the same time. Both ends of the cylindrical wound body R are trimmed as necessary in order to adjust the axial length.

  The number when the separation membrane unit U is stacked is determined according to the required permeation flow rate and may be two or more layers, but about 50 layers is the upper limit in consideration of operability.

  The spiral membrane element of the present invention has a structure that is restrained by the exterior material 15 and does not expand in diameter, but the exterior material 15 winds one or a plurality of sheets around the surface of the cylindrical wound body R. Can do. As the exterior material 15, polyester, polypropylene, polyethylene, polyvinyl chloride, glass fiber cloth, or the like can be used.

  The spiral membrane element of the present invention may be further provided with a perforated end member for preventing deformation (telescope or the like), a sealing material, a reinforcing material, and the like as necessary.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below.

Example 1
As shown in FIGS. 1 to 2, the supply-side channel material used in the present invention has a warp yarn diameter of 0.6 mm, a ratio of warp yarn diameter to weft yarn diameter of 2: 1, supply-side channel material thickness of 0.71 mm, warp yarn A polypropylene net with a spacing of 4 mm, a ratio of warp to weft spacing of 1: 1, a warp and weft crossing angle of 50 ° C. is 980 mm in the flow direction of the supply liquid, and 100 mm from the separation membrane in the direction perpendicular to the flow direction of the supply liquid. A spiral type separation membrane element having a diameter of 200 mm and a length of 1 m was manufactured by cutting to a short length of 610 mm, and 2000 cycles were performed by alternately performing filtration operation and backwash operation every 10 seconds. The supply pressure for the filtration operation was 0.15 MPa, and the backwash pressure was 0.2 MPa. When the spiral separation membrane element was disassembled, there was no separation of the separation membrane at a position adjacent to the adhesive resin (outer peripheral side sealing portion).

  In addition, as a separation membrane, a UF membrane of a type reinforced with a non-woven fabric is used, and the exterior material is FRP, the outer diameter of the central tube is 32 mm, the width of the sealing portion is 60 mm, and the number of unit stacks is 28 (Comparative Examples 1-2). The same).

Comparative Example 1
As shown in FIGS. 3 to 4, the warp yarn diameter is 0.6 mm, the ratio of warp yarn diameter to weft yarn diameter is 2: 1, the supply-side channel material thickness is 0.71 mm, the warp yarn interval is 4 mm, and the warp yarn interval and the weft yarn interval are A polypropylene net with a ratio of 1: 1, warp and weft crossing angle of 50 ° C. is cut to 980 mm in the feed liquid flow direction and 710 mm in a direction perpendicular to the feed liquid flow direction to 15 mm shorter than the separation membrane, and has a diameter of 200 mm. A 1 m spiral-type separation membrane element was manufactured, and 2000 cycle operation was performed by alternately performing filtration operation and backwash operation for 10 seconds each. The supply pressure for the filtration operation was 0.15 MPa, and the backwash pressure was 0.2 MPa. When the spiral separation membrane element was disassembled, 100 to 200 membrane separations of the separation membrane were confirmed per leaf at a position adjacent to the adhesive resin (outer peripheral side sealing portion).

Comparative Example 2
As shown in FIGS. 3 to 4, the warp yarn diameter is 0.6 mm, the ratio of warp yarn diameter to weft yarn diameter is 2: 1, the supply-side channel material thickness is 0.71 mm, the warp yarn interval is 4 mm, and the warp yarn interval and the weft yarn interval are A polypropylene net with a ratio of 1: 1 and a warp and weft crossing angle of 50 ° C. is cut to a feed liquid flow direction of 980 mm, and the direction perpendicular to the feed liquid flow direction is 485 mm which is 15 mm shorter than the separation membrane, and the diameter is 100 mm. A 1-m spiral separation membrane element was manufactured and operated with tap water as supply water at a filtration pressure of 0.2 MPa and a backwash pressure of 0.2 MPa. After a half year operation with a filtration time of 40 minutes and a backwash time of 1 minute, the spiral separation membrane element was disassembled, and separation of the separation membrane was 1 at a position adjacent to the adhesive resin (peripheral side sealing portion). An average of 100 per leaf was confirmed.

Process drawing which shows an example of the manufacturing method of the spiral type membrane element of this invention The principal part figure which shows an example of the spiral type membrane element of this invention Process drawing showing an example of a conventional method for manufacturing a spiral membrane element Main part of an example of a conventional spiral membrane element

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Separation membrane 2 Supply side flow path material 2a Outer peripheral side end of supply side flow path material 3 Permeation side flow path material 5 Central tube 12 Outer peripheral side sealing part 12a Inner peripheral side end of outer peripheral side sealing part R Cylindrical winding Body U separation membrane unit

Claims (3)

A separation membrane, a supply-side channel material, and a permeation-side channel material are provided with a cylindrical wound body that is wound in a spiral shape around the perforated central tube in a laminated state and the outer peripheral surface is constrained. In the spiral membrane element provided with a sealing portion for preventing mixing of the side fluid and the permeate side fluid,
The separation membrane facing through the permeate-side flow path member has an outer peripheral side sealing portion along the axial direction at the outer peripheral side end, and further on the inner peripheral side from the inner peripheral side end of the outer peripheral side sealing portion. The spiral-type membrane element is characterized in that an outer peripheral side end of the supply-side flow path material is disposed on the side.   2. The spiral membrane element according to claim 1, wherein the outer peripheral side sealing portion is in contact with an inner separation membrane or an inner outer peripheral side sealing portion without passing through a supply-side channel material over the entire circumferential width.   The spiral membrane element according to claim 1 or 2, wherein the separation membrane is reinforced with a nonwoven fabric on the back side of the separation active layer, and the separation active layer is disposed on the supply-side flow path material side. .

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