JP2015186770A - Membrane separation device and membrane separation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a membrane separation device and a membrane separation method, in each of which stains stuck to the vicinity of the permeation-side surface of a membrane can be discharged effectively.SOLUTION: The membrane separation device is constituted so that a supply-side flow passage material 2, a sheet-like separation membrane 1 and a permeation-side flow passage material 3 are piled in this order, and a supply-side flow passage and a permeation-side flow passage, which are formed on the inside of a main body 10, are divided from each other by the sheet-like separation membrane 1. The supply-side flow passage has an inlet 14 and an outlet 15 of an original liquid and the permeation-side flow passage has another inlet 16 and another outlet 17 of a sweep flow. At least one of the inlet 16 and the outlet 17 is selected and a plurality of the selected ones are formed at different positions.

Description

  The present invention relates to a membrane separation apparatus and a membrane separation method for separating a liquid by a sheet-like separation membrane.

  There are various types of separation membranes that separate liquids, etc., depending on the pore size and separation function. However, in terms of supplying undiluted solution to one side of the separation membrane and taking out permeate from the other side. It is common.

  For example, as a fluid separation element used for reverse osmosis filtration, ultrafiltration, etc., a supply side flow path material that guides the supply side fluid (raw water) to the surface of the separation membrane, a separation membrane that separates the supply side fluid, and a separation membrane A spiral-type membrane element in which a unit comprising a permeate-side channel material that guides a permeate-side fluid (permeate) that has permeated and separated from a supply-side fluid to a central tube (collection tube) is wound around a perforated central tube It is known (see, for example, Patent Document 1).

  Also, as described in Patent Document 2 below, when laminating and fixing a large number of flat membrane-like separation membranes at intervals, a corrugated spacer is interposed on the raw water side, and a mesh spacer on the permeate side There is known a membrane element in which a permeate extraction opening is provided in the laminated fixing part of each permeation chamber.

  In such a membrane separator, for the purpose of removing deposits and the like adhering to the surface of the separation membrane, an inlet and an outlet are provided in the supply-side flow path, and the supply liquid is made to flow near the surface of the separation membrane, In general, a cross flow method for separating the permeate is used. In addition, in a membrane separation apparatus for separating gas, for example, as in Patent Document 3, a structure that allows a sweep gas to flow through a permeate-side flow path may be employed in order to promote permeation of the membrane.

Japanese Patent Laid-Open No. 10-341 JP-A-6-277461 JP 2010-279885 A

  However, in a liquid membrane separation apparatus, if dirt or microorganisms adhere to the surface of the membrane on the permeate side, the permeate-side channel material may interfere with or pass dead even if the sweep flow is passed through the permeate-side channel. It was difficult to obtain the effect of discharging the dirt adhering to the vicinity of the permeation side membrane surface due to the space. The permeation side channel material has a generally low aperture ratio, and the porous support membrane (relatively coarse) of the sheet-like separation membrane is disposed on the permeate side channel side, so that dirt adheres to it. It can be said that it is difficult to maintain the effect of the sweep flow.

  Accordingly, an object of the present invention is to provide a membrane separation apparatus and a membrane separation method capable of effectively discharging dirt adhering to the vicinity of the permeation side membrane surface.

The above object can be achieved by the present invention as described below.
That is, in the membrane separation device of the present invention, the supply-side flow path material, the sheet-like separation membrane, and the permeation-side flow path material are laminated in this order, and the supply-side flow path and the permeation-side flow formed inside the main body. A membrane separation apparatus in which a passage is partitioned by the sheet-like separation membrane, wherein the permeate-side flow path has a sweep flow inlet and an outlet, and at least one of the inlet or the outlet has a plurality of different positions. The supply side flow path has an inlet and an outlet for the stock solution.

  According to the membrane separation apparatus of the present invention, since at least one of the inlet and outlet of the sweep flow provided in the permeate side flow path is provided at a different position, the plurality of the inlet and / or outlet of the sweep flow are switched and used. By doing so, the flow direction of the sweep flow can be changed. For this reason, in one sweep flow, dirt that could not be removed due to the permeation-side flow path material is easily removed by the other sweep flow, and the dead space in both flow directions is reduced. . As a result, the dirt adhering to the vicinity of the permeation side membrane surface can be effectively discharged.

  In the above, it is preferable that a plurality of both the inlet and the outlet of the sweep flow are provided at different positions. In this case, the flow direction of the sweep flow can be greatly changed, and the dirt adhering to the vicinity of the permeation side membrane surface can be discharged more effectively.

  The sweep flow inlet and outlet are located at a position where a center line connecting one inlet and the outlet of the sweep flow and a center line connecting the other inlet and the outlet form an angle of 30 to 150 ° C. Is preferably provided. By providing the sweep flow inlet and outlet at such an angle, it is possible to more reliably discharge the dirt adhering to the vicinity of the permeation side membrane surface.

  In addition, the main body has a flat shape that is rectangular in plan view, and one inlet and an outlet of the sweep flow are respectively provided in the vicinity of any opposing side of the main body having a rectangle, The other inlet and outlet of the sweep flow are preferably provided in the vicinity of the remaining opposing sides. By arranging the inlet and outlet of the sweep flow in this way, the flow directions of the respective flows can be changed vertically, and the dirt adhering to the vicinity of the permeation side membrane surface can be discharged more effectively.

Furthermore, the sheet-like separation membrane is preferably a composite semipermeable membrane in which a polyamide-based separation active layer is formed on a porous support membrane. In membrane separation using such a sheet-like separation membrane, a porous support membrane having a relatively coarse mesh is disposed on the permeate side flow path side, so that dirt such as scales and microorganisms are easily attached. Especially effective.
Moreover, it is preferable that a plurality of separation membrane units in which the sheet-like separation membranes are laminated via the permeation side flow path member are laminated. In this way, by using the separation membrane unit in which the sheet-like separation membranes are stacked via the permeate-side flow passage material, a plurality of permeate-side flow passages provided at positions where at least one of the inlet or the outlet of the sweep flow is different. It becomes easy to form in the separation membrane unit. Further, by stacking a plurality of such separation membrane units, an effective membrane area in the membrane separation device can be increased while forming a supply-side flow path between them.

  On the other hand, in the membrane separation method of the present invention, the membrane separation apparatus according to any one of the above is used to perform membrane separation while alternately using a plurality of the sweep flow inlets and outlets provided at different positions. It is characterized by. According to the membrane separation method of the present invention, it is possible to change the flow direction of the sweep flow by using a plurality of membrane separation devices provided in different positions at the inlet and outlet of the sweep flow provided in the permeate side flow path. In one sweep flow, even if the permeate-side flow path material gets in the way and cannot be removed, the other sweep flow facilitates the removal, and the dead space in both flow directions is reduced. As a result, the dirt adhering to the vicinity of the permeation side membrane surface can be effectively discharged.

The assembly perspective view which shows an example of the membrane separator of this invention. The longitudinal cross-sectional view which shows an example of the principal part of the membrane separator shown in FIG. The perspective view which shows the principal part of the other example of the membrane separator of this invention. The perspective view which shows the principal part of the other example of the membrane separator of this invention. The disassembled perspective view which shows the other example of the membrane separator of this invention.

  As shown in FIGS. 1 to 2, the membrane separation apparatus of the present invention includes a supply-side flow path material 2, a sheet-like separation membrane 1, and a permeation-side flow path material 3 that are stacked in this order. The supply-side flow path and the permeation-side flow path formed in the above are separated by the sheet-like separation membrane 1. In the present embodiment, as shown in FIGS. 1 to 2, the main body 10 is formed of an upper case member 11 and a lower case member 12, and the inner surface of the main body 10 is formed with the sheet-like separation membrane 1 via a seal member 13. An example is shown in which the supply-side flow path and the permeation-side flow path are formed on both surfaces of the sheet-like separation membrane 1 by sandwiching.

  In the present invention, the supply-side flow path has a stock solution inlet 14 and an outlet 15. In the illustrated example, the inlet 14 and the outlet 15 are provided at diagonal positions on the upper surface of the upper case member 11. It has been. As a result, while the stock solution flows along the center line A1 connecting the stock solution inlet 14 and the outlet 15, the stock solution is separated by the sheet-like separation membrane 1 to generate a permeate.

  Further, in the present invention, the permeate-side flow path has the sweep flow inlet 16 and the outlet 17, and at least one of the inlet 16 or the outlet 17 is provided at a different position. In the present embodiment, an example in which a plurality of both the inlet 16 and the outlet 17 are provided at different positions is shown. That is, the plurality of sweep flow inlets 16a and 16b and the outlets 17a and 17b are provided at different positions.

  When the sweep flow is provided using the sweep flow inlet 16a and the outlet 17a provided at one diagonal position of the lower case member 12, a center line A2 connecting the inlet 16a and the outlet 17a is provided. The sweep stream and permeate flow along. In the present invention, even when the inside of the main body 10 is cleaned without performing membrane separation, a sweep flow for cleaning can be flowed.

  On the other hand, when the sweep flow is made to flow using the sweep flow inlet 16b and the outlet 17b provided at the other diagonal position of the lower case member 12, the center line connecting the inlet 16b and the outlet 17b. A sweep and permeate flow along A3. In the present invention, the flow direction of the sweep flow can be changed by using a plurality of the sweep flow inlets 16 and / or outlets 17 as described above. However, it is easy to remove the dirt which cannot be removed due to the obstruction by the other sweep flow, and the dead space in the flow direction of both is reduced. As a result, the dirt adhering to the vicinity of the permeation side membrane surface can be effectively discharged.

  In the present invention, from the viewpoint of more effectively discharging the dirt adhering to the vicinity of the permeation side membrane surface, the center line A2 connecting one inlet 16a and the outlet 17a of the sweep flow, the other inlet 16b and the outlet 17b, It is preferable that the center line A3 connecting the two forms an angle of 30 to 150 ° C, more preferably an angle of 45 to 135 ° C, and still more preferably an angle of 60 to 120 ° C.

  Any material can be used as the material of the case members 11 and 12 forming the main body 10 as long as no problems such as elution of impurities and particles occur. For example, vinyl chloride resin, polycarbonate resin, polysulfone resin, ABS, and the like can be used. Examples of the resin include resins such as polyethylene and polypropylene. The lower case member 12 and the upper case member 11 can be fixed together by adhesion, fusion, welding, bolt fastening, or the like. When pressure resistance is required for the main body 10, it is preferable to use a metal such as stainless steel or a fiber reinforced resin such as GFRP or CFRP.

  Examples of the sheet-like separation membrane 1 include microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, and dialysis membranes, and those having a pore size, thickness, and size can be used according to the application and production method. . For example, the thickness of the sheet-like separation membrane 1 is 0.05 to 1.0 mm.

  The material of the sheet-like separation membrane 1 is polyethylene, polypropylene, polysulfone, polyethersulfone, vinylidene fluoride, polyacrylonitrile, polyvinyl chloride-polyacrylonitrile copolymer, aromatic polyamide, cellulose acetate, epoxy resin, polyamide. , Polyimide, and the like.

  In addition, as the sheet-like separation membrane 1, one made of a single material or a composite material can be used, and for example, it may be formed on a support such as a nonwoven fabric, and the separation active layer is formed on the porous support membrane. It may be a composite membrane. In the present invention, it is preferable to use a composite semipermeable membrane in which a polyamide-based separation active layer is formed on a porous support membrane.

  As the supply side channel material 2, a net made of resin or the like is preferably used. The thickness of the net is, for example, 0.3 to 1.8 mm. The net yarn diameter constituting the net is, for example, 0.2 to 1 mm. The net aperture ratio is, for example, 60 to 97%.

  In the present invention, the “net yarn” refers to a linear member constituting a net, and the cross section thereof is not limited to a circle, and may be any polygon such as a triangle or a rectangle, an ellipse or the like. Further, it is preferable that the intersecting net yarns are integrally formed, but the intersecting portion may or may not be fixed. The “net yarn diameter” refers to the maximum length in the cross section of the linear member constituting the net. For example, in the case of an elliptical cross section, the long diameter corresponds to the net yarn diameter.

  Examples of the material of the supply-side flow path member 2 include materials mainly composed of polypropylene, polyethylene, polysulfone, polytetrafluoroethylene, polyvinyl chloride, polyvinylidene fluoride, polyphenylene sulfide polyphenylene ether, polycarbonate, and nylon.

  Examples of the opening shape of the net include a triangle, a quadrangle (rhombus, square, rectangle, parallelogram, etc.), a hexagon, and the like.

  As the permeate-side channel material 3, a finer net than the supply-side channel material 2 is used, and a net of tricot knitting or plain weave made of resin or the like is preferably used. The thickness of the net is, for example, 0.2 to 1 mm. The net aperture ratio is 20 to 60%, for example.

  Examples of the material of the permeate-side flow path material 3 include materials mainly composed of polypropylene, polyethylene, polysulfone, polytetrafluoroethylene, polyvinyl chloride, polyvinylidene fluoride, polyphenylene sulfide polyphenylene ether, polycarbonate, and nylon.

  As the seal member 13, rubber such as silicone rubber or fluoro rubber, thermoplastic elastomer, or the like is used. Examples of the cross-sectional shape of the seal member 13 include a rectangle, a circle, and an ellipse. The thickness of the seal member 13 is preferably equal to or greater than that of the supply-side channel material 2 and the permeation-side channel material 3.

  As described above, according to the present invention, the permeate-side flow path has the sweep flow inlet 16 and the outlet 17, and at least one of the inlet 16 or the outlet 17 is provided in a plurality of different positions. It has the same structure, shape, material and the like as a conventional membrane separation apparatus, and any conventionally known technique can be adopted.

  On the other hand, the membrane separation method of the present invention uses the membrane separation apparatus of the present invention as described above to perform membrane separation while alternately using a plurality of sweep flow inlets 16 and outlets 17 provided at different positions. It is characterized by performing.

  When the membrane separation apparatus shown in FIGS. 1 to 2 is used, since the plurality of sweep flow inlets 16a and 16b and the outlets 17a and 17b are provided at different positions, the sweep flow is used alternately. From the inlet 16.

  When the sweep flow is provided using the sweep flow inlet 16a and the outlet 17a provided at one diagonal position of the lower case member 12, a center line A2 connecting the inlet 16a and the outlet 17a is provided. The sweep stream and permeate flow along. When the sweep flow is provided using the sweep flow inlet 16b and the outlet 17b provided at the other diagonal position of the lower case member 12, a center line A3 connecting the inlet 16b and the outlet 17b is provided. The sweep stream and permeate flow along. In the present invention, the flow direction of the sweep flow can be changed by using a plurality of the sweep flow inlets 16 and / or outlets 17 as described above. However, it is easy to remove the dirt which cannot be removed due to the obstruction by the other sweep flow, and the dead space in the flow direction of both is reduced. As a result, the dirt adhering to the vicinity of the permeation side membrane surface can be effectively discharged.

  As the sweep flow, there are a method of separately using a liquid having the same composition as the permeate and a method of circulating the permeate as it is. In addition, the cleaning liquid can be used as a sweep flow without performing membrane separation. As the cleaning liquid, pure water, upstream water, tap water, and those obtained by adding a cleaning agent to these can be used.

  The membrane separation method of the present invention employs various sheet-like separation membranes 1 such as microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, and dialysis membranes, so that various types of separation membranes can be used. Can be used for applications. Among these, the present invention is useful for separation using a semipermeable membrane such as a reverse osmosis membrane.

(Other embodiments)
(1) In the above-described embodiment, an example in which both the sweep flow inlet 16 and the outlet 17 are provided at different positions is shown. However, in the present invention, the sweep flow inlet 16 and the outlet 17 are provided. It is sufficient that at least one of the plurality is provided at a different position. For example, in the example shown in FIG. 1, only one inlet 16 may be provided in the center of the inlets 16a and 16b, or only one outlet 17 may be provided in the center of the outlets 17a and 17b.

  Further, the flow direction of the sweep flow is not limited to two directions, and may be three or more directions. In that case, at least one of the inlet 16 and the outlet 17 of the sweep flow is provided at three or more locations.

  (2) In the above-described embodiment, the sweep flow inlets 16a and 16b and the outlets 17a and 17b are provided at one pair of diagonal positions and the other pair of diagonal positions. As shown in FIG. 3, in the present invention, when the main body 10 has a flat shape that is rectangular in plan view, one of the inlets 16 a and the outlet 17 a of the sweep flow has a rectangular shape. It is preferable that each is provided in the vicinity of one of the opposing sides, and the other inlet 16b and outlet 17b of the sweep flow are provided in the vicinity of the remaining opposing sides. In FIG. 3, the configuration other than the lower case member 12 is omitted, but the same members as in FIG. 1 can be used.

  By arranging the inlets 16a and 16b and the outlets 17a and 17b in this way, the angle formed by the center line A2 connecting the inlet 16a and the outlet 17a and the center line A3 connecting the inlet 16b and the outlet 17b is further increased. It is possible to approach the vertical direction, and it is possible to discharge the dirt attached to the vicinity of the transmission side membrane surface more reliably.

  (3) In the above-described embodiment, an example in which the sheet-like separation membrane 1 is sandwiched by the seal member 13 so that the supply-side channel and the permeation-side channel are formed on both surfaces of the sheet-like separation membrane 1. Although shown, in the present invention, the sheet-like separation membrane 1 may be directly sandwiched by ultrasonic welding or the like of the case members 11 and 12 without using the seal member 13. It is also possible to seal the sheet-like separation membrane 1 using a sealing resin. Examples of the sealing resin include urethane resin and epoxy resin.

  (4) In the above-described embodiment, an example in which only one sheet-like separation membrane 1 is used is shown. However, as shown in FIGS. 4 to 5, in the present invention, a plurality of sheet-like separation membranes 1 are used. It is also possible to configure a membrane separation device.

  In this case, for example, as shown in FIG. 4, first, two sheet-like separation membranes 1, a permeate-side flow path material 3, and an adhesive tape 5 (or an adhesive or the like) are used to form two upper and lower sides. And a separation membrane unit MU in which the left and right sides are partially sealed. In that case, it arrange | positions so that the isolation | separation active layer side of the sheet-like separation membrane 1 may face the exterior. In the separation membrane unit MU, a plurality of sweep flow inlets 16a and 16b and a plurality of outlets 17a and 17b can be provided at diagonal positions. In the illustrated example, two sheet-like separation membranes 1 are used, but it is also possible to fold one sheet-like separation membrane 1 to produce a separation membrane unit MU.

  As shown in FIG. 5, a plurality of the separation membrane units MU are stacked with a plurality of supply-side flow path members 2 interposed, and housed in a container (not shown). The container is provided with an inlet and an outlet for the stock solution, and the stock solution flows in the direction of arrow A4. The concentrated stock solution is discharged from the outlet of the stock solution.

  The sweep flow is supplied from the inlets 16a and 16b of the sweep flow in the separation membrane unit MU via the supply pipes 18a and 18b, and is discharged from the discharge pipes 19a and 19b after exiting from the outlets 17a and 17b. The permeate separated from the stock solution by the sheet-like separation membrane 1 is discharged from the discharge pipes 19a and 19b after exiting from the outlets 17a and 17b of the separation membrane unit MU together with the sweep flow.

  In the present invention, the sweep flow is supplied to the supply pipe 18a and discharged from the discharge pipe 19a, and the sweep flow is supplied to the supply pipe 18b and discharged from the discharge pipe 19b. The flow direction of the flow can be switched from the direction of arrow A5 to the direction of arrow A6.

DESCRIPTION OF SYMBOLS 1 Sheet-like separation membrane 2 Supply side flow path material 3 Permeation side flow path material 10 Main body 14 Stock solution inlet 15 Stock solution outlet 16 Sweep flow inlet 17 Sweep flow outlet A2 Center connecting one inlet and outlet of sweep flow Line A3 Centerline connecting the other entrance and exit of the sweep flow

Claims (7)

The supply-side channel material, the sheet-like separation membrane, and the permeation-side channel material are laminated in this order, and the supply-side channel and the permeation-side channel formed inside the main body are partitioned by the sheet-like separation membrane. A membrane separation apparatus comprising:
The permeate-side flow path has a sweep flow inlet and outlet, and at least one of the inlet or outlet is provided at a different position, and
The supply-side flow path is a membrane separation device having an inlet and an outlet for a stock solution.   The membrane separation apparatus according to claim 1, wherein a plurality of both the inlet and the outlet of the sweep flow are provided at different positions.   The inlet and outlet of the sweep flow are provided at a position where a center line connecting one inlet and the outlet of the sweep flow and a center line connecting the other inlet and the outlet form an angle of 30 to 150 ° C. The membrane separation apparatus according to claim 2. The main body has a flat shape that is rectangular in plan view,
One inlet and outlet of the sweep flow are provided in the vicinity of any opposing side of the main body having a rectangular shape, and the other inlet and outlet of the sweep flow are in the vicinity of the remaining opposing sides. The membrane separation apparatus according to any one of claims 1 to 3, wherein each is provided.   The membrane separation apparatus according to any one of claims 1 to 4, wherein the sheet-like separation membrane is a composite semipermeable membrane in which a polyamide-based separation active layer is formed on a porous support membrane.   The membrane separation apparatus according to any one of claims 1 to 5, wherein a plurality of separation membrane units in which the sheet-like separation membranes are laminated via the permeate-side channel material are laminated.   7. A membrane separation method using the membrane separation apparatus according to claim 1 to perform membrane separation while alternately using a plurality of sweep flow inlets and outlets provided at different positions.