JP2002095935A - Spiral separation membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spiral separation membrane element which prevents a separation membrane from sinking into the groove part of a permeate passage material and suppresses the deformation of the separation membrane, thereby reducing its passage resistance and keeping an initial separation membrane performance. SOLUTION: A plain weave fabric 13 is superposed on one surface of a permeate passage material 10, and a separation membrane 2 is superposed on one surface of the permeate passage material 10 and on one surface of the plain weave fabric 13. These three sides are bonded to form a bag-shaped filter 4. The opening part of the bag-shaped membrane 4 is mounted to a liquid collecting pipe 5 consisting of a perforated hollow pipe, and the bag-shaped membrane 4 together with a raw liquid passage material 6 is wound around the outer peripheral surface of the liquid collecting pipe 5 to form a spiral separation membrane element 1. The plain weave fabric 13 comprises a plurality of weft threads 13a and a plurality of warp threads, and the tread diameter of the weft thread is larger than that of the warp thread. The plain weave fabric 13 is superposed on the permeate passage material 10 so that the weft threads 13a cross a groove part 12 vertically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral type separation membrane element used for a reverse osmosis membrane separation device, an ultrafiltration device, a microfiltration device and the like for separating a component in a fluid by a membrane.

[0002]

2. Description of the Related Art A membrane module is used in a filtration operation for separating a specific component contained in a fluid. For example, separation of salt in water as reverse osmosis membrane technology, separation of bacteria dispersed in liquid as ultrafiltration membrane technology, separation of solid turbid components in turbid liquid as microfiltration membrane technology, etc. Can be

[0003] Such a membrane module used for filtration includes a spiral type, a hollow fiber type, a plate-and-frame type, a rotary flat type, and the like according to the application and purpose.
There are various types of membrane modules such as a flat membrane laminate type. Among them, the spiral-type separation membrane module uses a sheet-like separation membrane whose active thinning is relatively easy, and has an advantage that it is excellent in pressure resistance and can be manufactured relatively inexpensively.

[0004] The spiral-type separation membrane module has a spiral-type separation membrane element housed in a pressure vessel.
This spiral-type separation membrane element forms a bag-like membrane by laminating a separation membrane on both sides of a permeate flow channel material and bonding three sides thereof, and opens the opening of the bag-like membrane from a perforated hollow tube. And a spiral wound around the outer peripheral surface of the liquid collecting tube together with the net-shaped raw liquid flow path material.

The stock solution flowing from one end face of the spiral type separation membrane element flows outside the bag-shaped separation membrane along the stock solution flow path material, and a part of the stock solution permeates through the separation membrane to become a permeate. After flowing along the liquid flow path material, it flows into the liquid collecting pipe and is discharged from the end of the liquid collecting pipe. Also, the stock solution that has not passed through the separation membrane is discharged from the other end face of the spiral type separation membrane element as a concentrated solution.

[0006] Tricot knitted fabrics are mainly used as the permeate flow path material. Since the permeated liquid is led to the side of the liquid collecting tube through the groove of the tricot knit and the separation membrane is supported by the convex portion between the grooves, the tricot knit requires strength. As a method of reinforcing the tricot knit, a method of impregnating the tricot knit with an epoxy resin to strengthen the tricot knit or a method of using a filament composed of a high melting point component and a low melting point component as disclosed in Japanese Patent Application Laid-Open No. 60-19001. There is a method in which the high melting point component and the low melting point component are melt-fixed by forming and heat-treating the tricot knit to strengthen the tricot knit. Single tricot knits having grooves on one side are often reinforced by epoxy resin or melt-fixing, and double tricot knits having grooves on both sides are often reinforced with epoxy resin.

[0007]

Normally, in order to perform membrane separation of a solution using a spiral separation membrane element using a reverse osmosis membrane as a separation membrane, it is necessary to apply a pressure higher than the osmotic pressure of the target solution. Becomes Normally, the pressure difference between the undiluted solution side and the permeate solution side is 0.5 to 1 depending on the use conditions.
Pressure is applied so as to be about 0 MPa.

FIG. 7 is an enlarged cross-sectional view of a conventional permeate flow path material made of a single tricot knitted fabric, and FIG. 8 is an enlarged cross-sectional view of a conventional permeate flow path material made of a double tricot knitted fabric.

As shown in FIG. 7, in a permeate flow path material 10 made of a single tricot knitted fabric, a plurality of mutually parallel grooves 12 are formed on one side as permeate flow paths. As shown in FIG. 8, in the permeated liquid flow path material 11 made of a double tricot knitted fabric, a plurality of mutually parallel grooves 12 are formed on both surfaces as permeated liquid flow paths.

However, when the permeated liquid channel material 10 shown in FIG. 7 is used, as shown in FIG.
Since the pressure of the permeate-side flow path sandwiched by the above is lower than the pressure of the stock solution-side flow path, the separation membrane 2 sinks into the groove 12. Also, in the case where the permeated liquid channel material 11 shown in FIG.
As shown in FIG. 0, the separation membrane 2 sinks into the groove 12 during operation. As described above, when the permeated liquid channel material 10 of FIG. 7 or the permeated liquid channel material 11 of FIG.
2 is closed and the flow path resistance increases.

Further, if the state in which the pressure difference between the stock solution side flow path and the permeate side flow path is large continues for a long time, the separation membrane 2 is deformed, the separation membrane 2 is damaged, and the performance of the separation membrane is reduced. Problems arise.

An object of the present invention is to prevent the separation membrane from sinking into the groove of the permeated liquid flow path material and to suppress the deformation of the separation membrane.
An object of the present invention is to provide a spiral-type separation membrane element having low flow path resistance and capable of maintaining initial separation membrane performance.

[0013]

The spiral type separation membrane element according to the present invention has a bag-shaped separation membrane having therein a permeate flow path material having a plurality of grooves formed on its surface. In a spiral separation membrane element in which the permeate flows along the permeate flow path material, the spiral type separation membrane element is wound around the outer peripheral surface of the perforated hollow tube, between the surface of the plurality of grooves of the permeate flow path material and the separation membrane. Plain weaves are arranged in this area.

In the spiral type separation membrane element according to the present invention, since the plurality of grooves formed on the surface of the permeate flow path material are covered with a plain woven material, the pressure of the raw liquid side flow path is reduced during operation. Even if the pressure becomes higher than the pressure of the flow channel, the separation membrane does not sink into the groove of the permeate flow channel material. Therefore, the groove is not closed by the separation membrane, and the flow path resistance does not increase. Further, since the separation membrane is not deformed, the separation membrane is not damaged. Therefore, the performance of the initial separation membrane can be maintained.

Preferably, the plurality of grooves extend substantially perpendicular to the perforated hollow tube. Accordingly, a plurality of grooves are formed along the flow direction of the permeated liquid, and the permeated liquid can flow quickly in the grooves. Therefore, the flow resistance decreases.

The plain weave is preferably arranged such that the weft of the plain weave is parallel to the perforated hollow tube. Thereby, the separation membrane is suppressed from sinking into the groove mainly due to the weft. Accordingly, the initial separation membrane performance can be maintained without increasing the flow path resistance.

[0017] The plain woven material preferably has a different yarn diameter between the weft and the warp. Thereby, the yarn diameter of the weft yarn that needs strength to suppress the depression of the separation membrane in the groove and the yarn diameter of the warp yarn that needs strength to maintain the form as a plain weave are individually selected. be able to. Thereby, an increase in the thickness of the plain weave is suppressed. Therefore, an increase in the outer diameter when the spiral-type separation membrane element is finished is suppressed.

It is preferable that the yarn diameter of the weft yarn of the plain weave is larger than the yarn diameter of the warp yarn. Thereby, the yarn diameter of the weft yarn requiring strength is increased, and the depression of the separation membrane in the groove can be efficiently suppressed.

The weft diameter of plain weave is 2 times the warp diameter.
It is preferably at least two times. As a result, the yarn diameter of the weft yarn is at least twice as large as the yarn diameter of the warp yarn that needs strength to maintain the form as a plain weave, and the weft yarn has a strength that can suppress the sinking of the separation membrane into the groove. Can be.

[0020] The spacing between the weft threads of the plain weave is 0.0001 m.
It is preferably at least m and at most 1 mm. If the weft spacing of the plain weave is greater than 1 mm, there is no effect of suppressing the separation membrane from sinking into the groove. On the other hand, when it is less than 0.0001 mm, the flow path resistance of the permeated liquid increases, or the resistance at the time of bonding with an adhesive becomes a cause of poor bonding. Therefore, by setting the interval between the weft threads to be 0.0001 mm or more and 1 mm or less, it is possible to prevent the separation membrane from sinking into the groove, prevent the flow path resistance of the permeated liquid from increasing, and prevent the occurrence of poor adhesion. It becomes possible.

[0021]

FIG. 1 is a partially cutaway perspective view showing an example of a spiral separation membrane element according to the present invention.

The spiral-type separation membrane element 1 shown in FIG. 1 has a plain weave 13 overlaid on one side of a permeate flow path material 10 and a separation membrane 2 on one side of each of the permeate flow path material 10 and the plain weave 13. To form a bag-like film 4 by gluing the three sides together, and attaching the opening of the bag-like film 4 to a liquid collecting tube 5 formed of a perforated hollow tube, and collecting the liquid together with the raw liquid flow path material 6. It is formed by spirally winding the outer peripheral surface of the tube 5.

FIG. 2 is a diagram showing the relationship between the liquid collecting tube 5 and the permeated liquid channel material 10 of the spiral separation membrane element 1 of FIG.
FIG. 3 is a plan view of the plain weave 13 of the spiral type separation membrane element 1 of FIG. 1, and FIG. 4 is a plan view of the plain weave 13 of FIG.

As shown in FIG. 2, the permeated liquid flow path member 10 is provided with a linear groove 12, and the permeated liquid is formed so that the groove 12 extends in a direction perpendicular to the axial direction of the liquid collecting tube 5. The channel material 10 is arranged. The groove 12 extends from the side on the liquid collection tube 5 side to the side on the outer peripheral side.

As shown in FIG. 3 and FIG.
3 is formed of a plurality of wefts 13a and a plurality of warps 13b, and the diameter of the wefts 13a is larger than the diameter of the warp 13b. The plain woven fabric 13 has a weft thread 13a formed of a permeated liquid channel material 1.
0 so as to be perpendicular to the groove 12
Overlaid on zero.

Further, the plain woven fabric 13 of the present embodiment has a weft 13a.
Is 75 denier, the warp yarn 13b has a yarn diameter of 25 denier, and the weft yarn 13a has an interval of 0.04 mm.

FIG. 5 is an enlarged sectional view of the bag-like membrane 4 of the spiral separation membrane element 1 of FIG.

As shown in FIG. 5, the groove portion 12 of the permeated liquid flow path member 10 is covered with a plain weave 13 so that the separation membrane 2 is along the plain weave 13 during operation.

As the plain woven fabric 13 of this embodiment, a plain woven yarn having a low-melting polyester as a sheath and a high-melting polyester as a core and stiffened by heat treatment is used. The material of the plain weave 13 is not particularly limited as long as it retains a shape usable as the plain weave 13 with respect to the pressure applied to the plain weave 13 and has little elution of components. Similarly, the manufacturing method and structure of the plain weave 13 are not particularly limited.

When the spiral type separation membrane module (not shown) is operated, as shown in FIG. 1, the stock solution 7 supplied from one end face of the spiral type separation membrane element 1 to the inside of the spiral type separation membrane element 1 Stock solution channel material 6
Flows in the axial direction, and is discharged as the concentrated liquid 9 from the other end face. In the course of the flow of the undiluted solution 7 inside the spiral separation membrane element 1, the permeate 8 permeating the separation membrane 2 passes through the groove 12 shown in FIG.
Of the liquid collecting tube 5 and discharged from the end of the liquid collecting tube 5.

FIG. 6 is an enlarged sectional view showing another example of the bag-shaped membrane of the spiral type membrane separation membrane element.

As shown in FIG. 6, the permeated liquid flow path material 11 is sandwiched by plain weaves 13, and the grooves 12 provided on both surfaces of the permeate liquid flow path material 11 are respectively covered by the plain weaves 13. Thus, the separation membrane 2 has a structure along the plain weave 13 during operation.

Since the grooves 12 of the permeate flow path members 10 and 11 are covered with the plain weave 13, even in the reverse osmosis membrane separation operation in which the pressure of the raw liquid flow path is higher than the pressure of the permeate flow path.
The separation membrane 2 does not sink into the groove 12 of the permeate flow path members 10 and 11. Therefore, the groove 12 is not closed by the separation membrane 2, and the flow path resistance does not increase. Further, since the separation membrane 2 is not deformed, the separation membrane 2 is not damaged, and the initial separation membrane performance can be maintained even after a state where the pressure difference is large for a long time.

In this embodiment, since the permeated liquid flow path members 10 and 11 are arranged so that the groove 12 extends in the direction perpendicular to the axial direction of the liquid collecting tube 5, the flow resistance of the permeated liquid is reduced. Also, the plain weave 13 is placed on the permeate flow path material 10 such that the weft 13a of the plain weave 13 is positioned perpendicular to the groove 12 of the permeate flow path material 10, that is, in parallel with the liquid collection tube 5. Can be stacked. Thereby, the separation membrane 2 is suppressed from sinking into the groove 12 mainly by the weft 13a. Thus, the initial separation membrane performance can be maintained without increasing the flow path resistance.

In this example, the weft 13 of the plain weave 13 is used.
The yarn diameter of a and the yarn diameter of the warp 13b are different. This allows
The yarn diameter of the weft 13a, which needs strength to suppress the depression of the separation membrane 2 in the groove 12, and the yarn diameter of the warp yarn 13b, which needs strength to maintain the form of the plain weave 13, are individually set. You can choose. This suppresses an increase in the thickness of the plain weave 13a. Therefore, compared to the case where the yarn diameters of the weft 13a and the warp 13b are the same, an increase in the module diameter when the spiral type separation membrane module is finished is suppressed.

Further, in this example, the weft 1 of the plain weave 13 is used.
Since the yarn diameter of 3a is larger than the yarn diameter of warp 13b, the groove 1
2 can be efficiently suppressed.

The yarn diameter of the weft 13a is preferably at least twice, preferably at least 2.5 times the yarn diameter of the warp 13b. At that time, the diameter of each yarn is preferably 1 denier or more and 1000 denier or less. More preferably 5 denier or more, 5
It is not more than 00 denier. As a result, the yarn diameter of the weft yarn 13a is twice or more the yarn diameter of the warp yarn 13b which requires strength to maintain the form of the plain weave material 13, and the weft yarn 13a causes the separation membrane 2 to sink into the groove 12 of the separation membrane 2. It can have a strength that can be suppressed.

If the spacing between the weft threads 13a of the plain weave 13 is larger than 1 mm, there is no effect of suppressing the separation membrane 2 from sinking into the groove 12. On the other hand, when it is less than 0.0001 mm, the flow path resistance of the permeated liquid increases, or the resistance at the time of bonding with an adhesive becomes a cause of poor bonding. For this reason, the interval between the weft threads 13a of the plain weave 13 is preferably 0.0001 mm or more and 1 mm or less. Further, in order to sufficiently suppress the depression of the separation membrane 2 into the groove portion 12 and sufficiently suppress the increase in the flow path resistance of the permeate, and further to sufficiently reduce the adhesion resistance, the interval between the weft yarns 13a is 0.001 mm or more. More preferably, it is 0.5 mm or less.

[0039]

[Example] A weft 13a having a yarn diameter of 75 denier and a warp yarn 13b having a yarn diameter of 25 denier, in which a core portion is made of high-melting polyester and a sheath portion is made of low-melting polyester, are plain-woven and heat-treated. Rigid, the plain weave 13 shown in FIG. 3 was produced. The interval between the wefts 13a is
0.04 mm. The permeated liquid channel material 10 has a yarn diameter of 70
It was prepared by impregnating a single tricot knit with denier and wale of 38 pieces / inch and course of 45 pieces / inch with an epoxy resin. As shown in FIG. 4, the plain weave 13 was overlapped on the permeated liquid flow path material 10 so that the weft 13 a was perpendicular to the groove 12, and the reverse osmosis membrane was installed on the plain weave 13. Then, a 5.8% saline solution is loaded on the reverse osmosis membrane at a pressure of 9 MPa, and the concentrated liquid outlet water volume is 5 L / mi.
A reverse osmosis membrane permeation experiment was performed under the conditions of n, a temperature of 25 ° C., and a hydrogen ion concentration of pH 7. The reverse osmosis membrane performance 60 minutes after the operation was as follows: the rejection was 99.7%, and the permeated water amount was 0.7 m ³ / m.
² / day. The surface of the reverse osmosis membrane after the experiment was not seen after the depression of the permeated liquid channel material 10 into the groove 12, and no damage was seen.

[Comparative Example] As a comparative example, the same reverse osmosis membrane as in the example was installed on the same permeate flow path material 10 as in the example, and a reverse osmosis membrane permeation experiment was performed under the same conditions as in the example. Was.
The reverse osmosis membrane performance 60 minutes after the operation showed a rejection of 99.5.
%, And the amount of permeated water was 0.5 m ³ / m ² / day. After the experiment, the surface of the reverse osmosis membrane was seen to have collapsed into the groove 12 of the permeated liquid channel material 10, and damage to the reverse osmosis membrane due to this was observed.

The same reverse osmosis membrane is used in the example and the comparative example, and the only difference is whether or not the plain weave 13 is used. The low rejection rate after the operation in the comparative example is due to the fact that the reverse osmosis membrane was damaged when it was depressed into the groove 12 of the permeated water flow path member 10. Further, the low permeated water amount is because the flow passage resistance was increased because the reverse osmosis membrane was depressed into the groove 12 to close the flow passage.

As described above, according to the present invention, it is possible to prevent the separation membrane from sinking into the groove of the permeated liquid channel material and to suppress the deformation of the separation membrane. Therefore, it is possible to provide a spiral-type separation membrane element having low flow path resistance and capable of maintaining initial separation membrane performance.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a spiral separation membrane element according to the present invention.

FIG. 2 is a view showing a relationship between a liquid collection tube and a permeate flow path material of the spiral separation membrane element of FIG.

FIG. 3 is a plan view of a plain weave of the spiral separation membrane element of FIG. 1;

FIG. 4 is a plan view in which the plain weave of FIG. 3 is superimposed on the permeate flow path material of FIG. 2;

FIG. 5 is an enlarged sectional view of a bag-like membrane of the spiral separation membrane element of FIG.

FIG. 6 is an enlarged sectional view showing another example of the bag-shaped membrane of the spiral separation membrane element.

FIG. 7 is an enlarged cross-sectional view of a permeated liquid flow path material made of a conventional single tricot knitted fabric.

FIG. 8 is an enlarged cross-sectional view of a permeated liquid flow path material made of a conventional double tricot knitted fabric.

FIG. 9 is a diagram for explaining a problem when the permeated liquid flow path material of FIG. 7 is used for a spiral type separation membrane element.

FIG. 10 is a diagram for explaining a problem when the permeated liquid channel material of FIG. 8 is used for a spiral separation membrane element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral-type separation membrane element 2 Separation membrane 4 Bag-shaped membrane 5 Liquid collecting tube 10, 11 Permeate flow path material 12 Groove 13 Plain weave 13a Weft 13b Warp

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Ando 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation F-term (reference) 4D006 GA03 GA06 GA07 HA61 JA04A JA04B JA06A JA06B JA19A JB09 KE03Q KE03R KE04Q KE04R KE15Q KE15R KE16Q KE16R

Claims (7)

[Claims] 1. A bag-shaped separation membrane internally provided with a permeate flow path material having a plurality of grooves formed on its surface is wound around the outer peripheral surface of a perforated hollow tube. A spiral-type separation membrane element in which a permeate flows along, wherein a plain woven material is disposed between a surface of the permeate flow path material on the side of the plurality of grooves and the separation membrane. Separation membrane element. 2. The spiral separation membrane element according to claim 1, wherein the plurality of grooves extend substantially perpendicular to the perforated hollow tube. 3. The spiral-type separation membrane element according to claim 2, wherein the plain woven material is disposed so that the weft of the plain woven material and the perforated hollow tube are parallel to each other. 4. The spiral separation membrane element according to claim 1, wherein the plain woven material has a yarn diameter of the weft and a yarn diameter of the warp different from each other. 5. The yarn diameter of the weft yarn of the plain weave is greater than the yarn diameter of the warp yarn.
The spiral separation membrane element according to any one of the above. 6. The yarn diameter of the weft yarn of the plain weave is at least twice the yarn diameter of the warp yarn.
6. The spiral separation membrane element according to any one of items 1 to 5, 7. The interval between the weft threads of the plain weave is 0.
The spiral separation membrane element according to any one of claims 1 to 6, wherein the length is from 0001 mm to 1 mm.