JP5081217B2 - Separation membrane unit and separation membrane element provided with the same - Google Patents

Description

  The present invention relates to a separation membrane unit for producing a permeate by filtering an object to be filtered, and a separation membrane element including the separation membrane unit.

  As a method for filtering raw water (filter target) such as waste water or seawater using a reverse osmosis method, a total filtration method and a cross flow filtration method are generally known. The total filtration method is a method of filtering the whole amount of raw water to be supplied. For example, the raw water is supplied in a direction orthogonal to the separation membrane. On the other hand, the cross-flow filtration method clogs the separation membrane by supplying raw water in a direction parallel to the separation membrane and circulating the raw water as necessary while filtering a part of the raw water through the separation membrane. It is a system that can be filtered while suppressing the above.

  As an example of a separation membrane unit that can be used when raw water is filtered by the crossflow filtration method, as disclosed in Patent Document 1 below, folded portions are alternately formed on one side and the other side. In addition, a pleated type separation membrane unit having a separation membrane which is folded back into a plurality of pleats is known. In the configuration disclosed in Patent Document 1, the water collecting pipe 4 is provided so as to penetrate the central portion of the separation membrane folded back into a pleat shape, and the permeated water generated by filtering raw water through the separation membrane. However, it is led to the outside of the separation membrane unit through the water collecting pipe 4.

  In addition, as another example of a separation membrane unit that can be used when raw water is filtered by a cross flow filtration method, a plurality of separation membranes are laminated in a certain lamination direction as disclosed in Patent Document 2 below. A laminated separation membrane unit having the above structure is known. In the configuration disclosed in Patent Document 2, two pipes 12 are provided so as to penetrate a plurality of stacked separation membranes in the stacking direction, and permeated water is stacked on the separation membranes via the pipes 12. It is led to both sides of the direction.

JP-A-54-17378 JP 2008-183561 A

  In the configuration in which the water collecting pipe 4 penetrates the central portion of the separation membrane as in the above-mentioned Patent Document 1, the separation membrane cannot be provided in the portion where the water collecting tube 4 is arranged, so that the installation space for the separation membrane is secured to the maximum. There is a problem that the filtration efficiency is lowered by that amount.

  In addition, as in Patent Document 2, a configuration in which a pipe that penetrates a plurality of separation membranes in the stacking direction has a problem that the structure becomes complicated and the manufacturing cost increases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a separation membrane unit and a separation membrane element including the separation membrane unit that can perform good filtration by a cross-flow filtration method with a simple configuration. To do.

The separation membrane unit according to the present invention is a separation membrane unit for producing a permeate by filtering an object to be filtered , and each of the plurality of separation membranes is one surface of a sheet-like porous substrate. A separation active layer is formed on the supply side, and the separation active layers of the adjacent separation membranes are stacked so as to face each other, whereby a supply side as a flow path of a filtration target object to be supplied between the adjacent separation membranes A flow path is formed, and an object to be filtered is supplied from the end side of the separation membrane into the supply-side flow path in a direction orthogonal to the stacking direction of the separation membrane, and generated. The plurality of permeate-side flow paths as permeate flow paths extend in a direction orthogonal to the laminating direction and in a direction orthogonal to the supply direction so as to extend in parallel to the supply direction of the filtration object. On both sides of the separation membrane Made is characterized in that is.

  According to such a configuration, the permeation side flow path is disposed on both sides of the plurality of separation membranes in a direction orthogonal to the stacking direction of the separation membranes and in a direction orthogonal to the supply direction of the filtration object. Thereby, the permeation | transmission side flow path can be formed adjacent to each separation membrane in the both sides of the said orthogonal direction of each separation membrane. As a result, the permeate generated in each separation membrane can be guided to the permeate-side flow path with a simple configuration, so that the filtration by the crossflow filtration method can be performed satisfactorily.

  Further, for example, when the separation membrane unit is accommodated in the exterior material having a cylindrical cross section, between the inner peripheral surfaces of the exterior materials respectively formed on both sides in the orthogonal direction of each separation membrane A permeate-side channel can be provided in the empty space. Therefore, the installation space for the separation membrane can be secured to the maximum, and filtration can be performed more efficiently.

  Further, when the permeation side flow paths are symmetrically arranged on both sides of the separation membrane, uneven flow hardly occurs, and filtration by a cross flow filtration method can be performed more satisfactorily.

  In the separation membrane unit according to the present invention, three or more separation membranes are laminated in a certain lamination direction, and both ends of the separation membrane in a direction perpendicular to the lamination direction and perpendicular to the supply direction Each of the permeate-side flow paths is formed on the part side.

  According to such a configuration, the permeation-side flow paths are formed on both end sides of each separation membrane in the direction orthogonal to the stacking direction and the direction orthogonal to the supply direction, whereby each separation membrane is separated. A permeate flow path can be formed in the vicinity of both ends of the membrane in the orthogonal direction. Therefore, the permeate generated in each separation membrane from both ends can be easily guided to the permeate side flow path.

  In the separation membrane unit according to the present invention, a plurality of the separation membranes are folded back in a pleated form in a stacked state, thereby alternately turning back to one side and the other side of the two separation membranes. The permeation side flow path is formed on each of the one side and the other side across the separation membrane.

  According to such a configuration, the permeation-side flow path is formed in the vicinity of each folded portion of the separation membrane by forming the permeation-side flow path on one side and the other side with the separation membrane interposed therebetween. Can do. Therefore, the permeate generated in each separation membrane from these folded portions can be easily guided to the permeate-side flow path.

  In the separation membrane unit according to the present invention, each of the plurality of separation membranes has a separation active layer formed on one surface of the sheet-like porous substrate, and the separation active layers of the adjacent separation membranes face each other. It is characterized by being laminated so as to.

  According to such a configuration, the adjacent separation membranes in which the separation active layer is formed on one surface of each sheet-like porous substrate are overlapped so that the separation active layers face each other. The isolation active layer is not exposed to the outside, and damage to the isolation active layer can be prevented.

  The separation membrane unit according to the present invention is characterized in that a supply-side channel material for forming the supply-side channel is provided between the adjacent separation membranes.

  According to such a configuration, the supply-side channel can be reliably formed by the supply-side channel material provided between the adjacent separation membranes, so that the filtration object can be filtered better.

  The separation membrane element according to the present invention includes the separation membrane unit and an exterior material that covers the outside of the separation membrane unit.

It is the exploded sectional view showing an example of the lamination mode of the separation membrane which constitutes the separation membrane unit concerning one embodiment of the present invention. It is the schematic perspective view which showed the structural example of the separation membrane unit. It is the schematic perspective view which showed the structural example of the separation membrane unit. It is the schematic sectional drawing which showed the aspect at the time of folding a separation membrane like FIG. 2B. It is the schematic sectional drawing which showed the aspect at the time of folding a separation membrane like FIG. 2B. It is the schematic sectional drawing which showed the aspect at the time of folding a separation membrane like FIG. 2B. It is the schematic perspective view which showed the structural example of the separation membrane element. It is the schematic perspective view which showed the structural example of the separation membrane element. It is the schematic perspective view which showed the structural example of the separation membrane element.

  FIG. 1 is an exploded cross-sectional view showing an example of a stacking mode of separation membranes 1 constituting a separation membrane unit according to an embodiment of the present invention. In this example, a channel material 2 as a spacer is sandwiched between adjacent separation membranes 1. The separation membrane 1 may be an ultrafiltration membrane, a nanofiltration membrane, a reverse osmosis membrane, a dialysis membrane, or the like, but in the case of a reverse osmosis membrane or an ultrafiltration membrane from the relationship between the pressure of raw water and the flow rate of permeated water, etc. It is effective for.

  Each separation membrane 1 has the same configuration and has a sheet-like porous substrate 3 and a separation active layer (skin layer) 4 formed on one surface of the porous substrate 3. The separation membrane 1 may further include not only the porous substrate 3 and the separation active layer 4 but also other layers. The thickness of the separation membrane 1 is generally about 20 to 2000 μm. The adjacent separation membranes 1 are overlapped on both sides with the flow path material 2 sandwiched so that the separation active layers 4 face each other. Thus, it is preferable that the two separation membranes 1 and the flow path material 2 are laminated in a state where the separation active layer 4 of each separation membrane 1 is in contact with the surface of the flow path material 2 facing each other.

  The porous substrate 3 can be formed using, for example, polysulfone, polyethersulfone, PVDF, polyethylene, polyimide, epoxy, or the like. In addition to the above materials, the porous substrate 3 may be reinforced with a reinforcing material such as a nonwoven fabric, a woven fabric, a knitted fabric, or a net. The separation active layer 4 is formed of a dense and non-porous thin film, and the material of the separation active layer 4 is not particularly limited, and examples thereof include cellulose acetate, ethyl cellulose, polyether, polyester, polyamide, and silicon. The thickness of the separation active layer 4 formed on the porous substrate 3 is not particularly limited, but is usually about 0.05 to 2 μm, and preferably 0.1 to 1 μm. The channel material 2 can be formed using, for example, a knitted fabric or a net.

  As shown in FIG. 1, adjacent separation membranes 1 each having a separation active layer 4 formed on one surface of a sheet-like porous substrate 3 are overlapped so that the separation active layers 4 face each other. Therefore, the isolation active layer 4 is not exposed to the outside, and the isolation active layer 4 can be prevented from being damaged.

  2A and 2B are schematic perspective views showing a configuration example of the separation membrane unit 10. This separation membrane unit 10 is for generating permeated water (permeate) by filtering raw water (subject to be filtered). In the example of FIG. 2A, three separation membranes 1 are arranged in a certain stacking direction. In the example of FIG. 2B, a plurality of separation membranes 1 are folded back and folded into a pleat shape.

  In the example of FIG. 2A, a plurality of sets of two separation membranes 1 and flow path members 2 that are superposed on each other in the manner shown in FIG. 1 are stacked in the stacking direction A1. The separation membrane unit 10 employs a cross-flow filtration method in which raw water such as waste water and seawater is supplied in a direction orthogonal to the stacking direction A1, that is, in a direction B1 parallel to the separation membrane 1. In addition, raw water is supplied from one end on the upstream side in the supply direction B1 in the plurality of stacked separation membranes 1 and flow path members 2. The supplied raw water passes through the raw water flow path (supply-side flow path) formed between the adjacent separation membranes 1 by the flow path material 2 and enters between the adjacent separation membranes 1, to the separation membrane 1. In the process of flowing in the parallel direction (supply direction B1), the separation membrane 1 is filtered. At this time, the flow path member 2 functions as a supply-side flow path material for forming the supply-side flow path, and the supply-side flow path material can reliably form the supply-side flow path.

  On both ends (upper and lower sides in FIG. 2A) in the direction C1 perpendicular to the stacking direction A1 and the supply direction B1 in the separation membrane 1, water collecting pipes extending in parallel to the supply direction B1 that is the raw water flow direction. 6 is provided. These water collecting pipes 6 are formed with a permeate side flow path 7 as a flow path of the permeated water.

  The permeated water generated by filtering the raw water flowing in the supply-side channel in the supply direction B1 by the separation membrane 1 is the outside of each pair of separation membranes 1, more specifically, the adjacent separation membranes 1 It flows out to the permeation side flow path (not shown) formed between them, and is guided to the upper side and the lower side in FIG. 2A through the permeation side flow path, and through the water collection structure (not shown). Water is collected inside. The permeated water collected in this way is guided to the outside of the separation membrane unit 10 through the water collection pipe 6. A permeation-side channel material for forming a permeation-side channel may be provided between adjacent pairs of separation membranes 1.

  In this example, sealing portions 8 are respectively formed between the plurality of laminated separation membranes 1 and flow path materials 2 and the water collecting pipes 6 provided on both end sides in the orthogonal direction C1. . The sealing portion 8 is for separating raw water passing between adjacent separation membranes 1 and permeated water generated outside the adjacent separation membranes 1, and only permeated water is a sealing portion. 8 is led to the water collecting pipe 6. The water collecting mechanism may be formed in the sealing portion 8 or may be formed separately from the sealing portion 8.

  In the example of FIG. 2A as described above, the permeation-side flow paths 7 are respectively provided at both end portions (upper side and lower side in FIG. 2A) in the direction C1 orthogonal to the stacking direction A1 and the supply direction B1 in each separation membrane 1. By being formed, the permeation-side flow path 7 can be formed close to both ends of each separation membrane 1 in the orthogonal direction C1. Therefore, the permeated water generated in each separation membrane 1 from those both ends can be easily guided to the permeation side flow path 7.

  In the example of FIG. 2B, two separation membranes 1 and a flow path material 2 that are superposed on each other in the manner shown in FIG. 1 are folded back into a pleat shape (bellows shape), thereby two separation membranes. Folded portions 5 are alternately formed on one side and the other side (upper and lower in FIG. 2B). Therefore, it is preferable that both of the two separation membranes 1 and the flow path material 2 have flexibility. The two separation membranes 1 and the flow path member 2 that are folded back multiple times in a pleat form are in a state where the folded portions are adjacent to each other and stacked in a certain direction A2. Each folded portion 5 extends in a direction B2 orthogonal to the stacking direction A2 of the separation membrane 1 and the flow path material 2 as described above, and adjacent folded portions 5 are arranged in the stacking direction A2.

  The separation membrane unit 10 employs a cross-flow filtration method in which raw water such as waste water and seawater is supplied in a direction orthogonal to the stacking direction A2, that is, in a direction B2 parallel to the separation membrane 1. In addition, raw water is supplied from one end of the upstream side of the supply direction B2 in the two separation membranes 1 and the flow path member 2 that are folded back multiple times in a pleat shape. The supplied raw water passes between the two separation membranes 1 through the raw water flow passage (supply side flow passage) formed between the two separation membranes 1 by the flow passage material 2, and the separation membrane 1. Is filtered by the separation membrane 1 in the process of flowing in the parallel direction (supply direction B2). At this time, the channel material 2 functions as a supply-side channel material for forming the supply-side channel, and the supply-side channel can be reliably formed by the supply-side channel material. For example, raw water can be filtered well.

  On the two sides (upper side and lower side in FIG. 2B) in the direction C2 perpendicular to the laminating direction A2 and the supply direction B2 of the two separation membranes 1 and the flow path member 2 that are folded back multiple times in a pleat shape, the raw water flows. A water collecting pipe 6 extending in parallel to the supply direction B2, which is the direction, is provided. These water collecting pipes 6 are provided on one side and the other side where the folded-back portions 5 are formed with respect to the two separation membranes 1 and the flow path material 2 which are folded back in a plurality of pleats. A permeate-side flow path 7 as a flow path of permeated water is formed inside.

  The permeated water generated by filtering the raw water flowing in the supply-side flow path in the supply direction B2 by the separation membrane 1 is separated from the outside of the two separation membranes 1, more specifically by being folded back. It flows out to the permeation side flow path (not shown) formed between the membranes 1 and is guided to the upper side and the lower side in FIG. 2B through the permeation side flow path, and is collected via a water collection structure (not shown). Water is collected in the water pipe 6. The permeated water collected in this way is guided to the outside of the separation membrane unit 10 through the water collection pipe 6. A permeation-side channel material for forming a permeation-side channel may be provided between adjacent separation membranes 1 by being folded.

  In this example, a sealing portion 8 is provided between two separation membranes 1 and a flow path member 2 that are folded back multiple times in a pleat shape, and a water collecting pipe 6 provided on one side and the other side thereof. Is formed. This sealing portion 8 is for separating raw water passing between the two separation membranes 1 and permeated water generated outside the two separation membranes 1, and only the permeated water is sealed. It is guided to the water collecting pipe 6 through the stop 8. The water collecting mechanism may be formed in the sealing portion 8 or may be formed separately from the sealing portion 8.

  In the example of FIG. 2B as described above, the permeation-side flow paths 7 are formed on one side and the other side (the upper side and the lower side in FIG. 2B) with the separation membrane 1 interposed therebetween, so The permeate-side flow path 7 can be formed in the vicinity of the folded portion 5. Therefore, the permeated water generated in each separation membrane 1 from the folded-back portions 5 can be easily guided to the permeation side flow path 7.

  In the present embodiment, the permeate side flow path 7 has both sides of a plurality of separation membranes 1 sandwiched in the directions C1 and C2 perpendicular to the laminating directions A1 and A2 of the separation membrane 1 and the raw water supply directions B1 and B2 (see FIG. 2A and 2B), the permeation-side flow path 7 can be formed close to each separation membrane 1 on both sides in the orthogonal directions C1 and C2 of each separation membrane 1. . Thereby, since the permeated water produced | generated in each separation membrane 1 can be guide | induced to the permeation | transmission side flow path 7 by simple structure, the filtration by a crossflow filtration system can be performed favorably.

  Further, as in the example of FIGS. 2A and 2B, when the permeation-side flow paths 7 are symmetrically arranged on both sides of the separation membrane 1, uneven flow hardly occurs, and filtration by the crossflow filtration method is performed more satisfactorily. be able to.

  3A to 3C are schematic cross-sectional views showing a mode when the separation membrane 1 is folded back as shown in FIG. 2B. FIG. 3A is an example showing a state in which the two separation membranes 1 and the channel material 2 that are superposed on each other are in the middle of being folded back into a pleat shape, and a V-shape is formed so that the folded portion 5 has an acute angle. Is bent. FIG. 3B is an example showing a state in which the two separation membranes 1 and the channel material 2 that are superposed on each other are folded back in a pleated manner, but the folded portion 5 is U-shaped. It has a curved shape.

  In the example of FIG. 2B, the configuration in which the flow path material 2 is sandwiched between the two separation membranes 1 has been described. However, if the flow path of the raw water can be secured between the two separation membranes 1, the flow path material 2 can be omitted. For example, as in the example shown in FIG. 3C, if each of the separation active layers 4 in the two separation membranes 1 is a flat surface rather than a flat surface, the two separation active layers 4 are in contact with each other. When the separation membranes 1 are superposed, the convex portions of the separation active layers 4 come into contact with each other, and a flow path of raw water can be formed between the concave portions. As the shape of the convex portion, various shapes such as a rhombus, a parallelogram, an ellipse, an oval, a circle, a square, and a triangle can be adopted as long as the flow path of the raw water can be secured. Can do. In the example of FIG. 3C, the folded portion 5 of the separation membrane 1 is bent in a V shape. However, the shape is not limited to such a shape. For example, the folded portion 5 may be curved in a U shape. Good.

  3A to 3C show a mere example of a mode when the separation membrane 1 is folded back as shown in FIG. 2B. As long as the two separation membranes 1 have a shape that is folded back multiple times, other various types are shown. Shape can be adopted. As a method of folding the two separation membranes 1, there are, for example, a method of folding the two separation membranes 1 in a state of being overlapped, and a method of folding the separation membranes 1 after being folded. In any of these methods, a folded portion 5 having a shape corresponding to the member is formed by pressing a member such as a guillotine blade against the separation membrane 1 and folding the separation membrane 1 at the pressed portion. be able to. In addition, a method of folding the separation membrane 1 using a pinch roll or a pinch bar is also conceivable.

  In addition, even when a plurality of separation membranes 1 are stacked as shown in FIG. 2A, if separation of the raw water can be ensured between the adjacent separation membranes 1, the adjacent separation membranes 1 as shown in FIG. The flow path material 2 is not limited to the configuration in which the flow path material 2 is sandwiched therebetween, and the flow path material 2 may be omitted. In this case, as in the example shown in FIG. 3C, if each separation active layer 4 in the adjacent separation membrane 1 is a flat surface rather than a flat surface, the separation active layers 4 are adjacent so that they come into contact with each other. When the separation membranes 1 are overlapped, the projections of the separation active layers 4 come into contact with each other, and a flow path of raw water can be formed between the depressions.

  4A to 4C are schematic perspective views showing a configuration example of the separation membrane element 100. FIG. 4A to 4C show an example in which the separation membrane 1 of FIG. 2B is used, the same configuration can be adopted for other separation membranes 1 as exemplified by the separation membrane 1 of FIG. 2A.

  The separation membrane unit 10 can be used with its outer side covered with an exterior material 9 or the like as necessary. In this example, a separation membrane element 100 is configured by providing a separation membrane unit 10 in a cylindrical exterior member 9. You may provide the end member for setting the flow path of raw | natural water or permeated water in an axial direction edge part as needed.

  FIG. 4A shows an example of the separation membrane element 100 in which the separation membrane unit 10 of FIG. 2B is provided in the exterior material 9. Since the two separation membranes 1 and the flow path member 2 that are folded back multiple times in a pleat shape have a rectangular cross section, it is preferable to use the exterior material 9 having an inner diameter slightly larger than the length of the diagonal line.

  In this example, the sealing portions 8 are provided respectively on one side and the other side (upper and lower in FIG. 4A) of the two separation membranes 1 and the flow path material 2 that are folded back in a pleat shape. Thus, a space 101 for circulating raw water between these sealing portions 8 is formed, and permeated water is circulated between each sealing portion 8 and the inner peripheral surface of the exterior material 9 facing it. A space 102 is formed. In order to separate the space 101 and the space 102 in a water-tight manner, it is preferable that the edge of each sealing portion 8 and the inner peripheral surface of the exterior material 9 are in close contact with each other. A seal member may be provided.

  In the example of FIGS. 4B and 4C, the space 102 is filled with the sealing portion 8 except for the permeate-side flow path 7, and therefore the outer peripheral surface of the sealing portion 8 is the inner peripheral surface of the exterior material 9. It becomes the shape corresponding to. According to such a configuration, as shown in FIGS. 4B and 4C, the permeation-side flow path 7 having an arbitrary cross-sectional area can be formed according to the shape of the hole formed in the sealing portion 8. it can.

  As illustrated in FIGS. 4A to 4C, when the separation membrane unit 10 is accommodated in the exterior material 9 having a cylindrical cross section, one side and the other side of the two separation membranes 1 are used. The permeation-side flow path 7 can be provided in an empty space (space 102) between the inner peripheral surface of the exterior material 9 formed respectively (upward and downward in FIGS. 4A to 4C). Therefore, the installation space for the two separation membranes 1 can be secured to the maximum, and filtration can be performed more efficiently.

  However, the exterior material 9 is not limited to a circular cross section, and may be other shapes such as a rectangular shape, or the exterior material 9 may be omitted. Even in the case where the packaging material 9 is omitted, in this embodiment, the adjacent separation films 1 are overlapped so that the separation active layers 4 face each other, and the separation active layer 4 is not exposed. There is no possibility that the separation active layer 4 is damaged.

  In the above embodiment, although the case where the filtration target object is raw water was demonstrated, other raw | natural solutions, such as oil instead of water, may be sufficient as gas.

DESCRIPTION OF SYMBOLS 1 Separation membrane 2 Flow path material 3 Porous base material 4 Separation active layer 5 Folding part 6 Water collecting pipe 7 Permeation side flow path 8 Sealing part 9 Exterior material 10 Separation membrane unit 100 Separation membrane element 101 Space 102 Space

Claims (5)

A separation membrane unit for producing a permeate by filtering an object to be filtered,
A plurality of separation membranes are adjacent to each other by forming a separation active layer on one surface of each sheet-like porous substrate and laminating the separation active layers of adjacent separation membranes so as to face each other. A supply-side flow path as a flow path for the filtration target to be supplied is formed between the separation membranes, and from the end side of the separation membrane to the supply-side flow path with respect to the stacking direction of the separation membranes The filtration object is supplied in the orthogonal direction,
The permeate-side flow path as a flow path of the generated permeate extends in a direction orthogonal to the stacking direction and a direction orthogonal to the supply direction so that each of the permeate-side flow paths extends in parallel to the supply direction of the filtration object. The separation membrane unit is formed on both sides of the plurality of separation membranes. Three or more separation membranes are laminated in a certain lamination direction,
The permeation-side flow path is formed on each end of the separation membrane in a direction orthogonal to the stacking direction and in a direction orthogonal to the supply direction, respectively. Separation membrane unit. The separation membrane is folded two or more times in a pleated form in a stacked state, whereby folded portions are alternately formed on one side and the other side of the two separation membranes,
2. The separation membrane unit according to claim 1, wherein the permeation side flow path is formed on each of the one side and the other side across the separation membrane. 2. The separation membrane unit according to claim 1 , wherein a supply-side channel material for forming the supply-side channel is provided between the adjacent separation membranes. The separation membrane unit according to any one of claims 1 to 4 ,
A separation membrane element comprising: an exterior material that covers the outside of the separation membrane unit.

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