JP2000051671A - Spiral separation membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spiral separation membrane element low in flow channel resistance and capable of keeping initial separation membrane capacity by preventing the depression of the permeated liquid flow channel material of separation membrane in groove parts and suppressing the deformation of the separation membranes. SOLUTION: A permeated liquid flow channel material 3 is formed from two permeated liquid flow channel material elements 10a. A plurality of mutually parallel groove parts 12 are formed to the single surfaces of the elements 10a and two elements 10a are superposed one upon another so that the groove parts 12 are opposed to each other. A bag-shaped membrane 4 is formed by superposing separation membranes 2 to both surfaces of the channel material 3 to bond three sides of them and the opening part of the bag-shaped membrane 4 is attached to a liquid collecting pipe 5 comprising a perforated hollow pipe and sprirally wound around the outer peripheral surface of the liquid collecting pipe 5 along with a raw liquid flow channel material 6 to form a spiral separation membrane element 1.

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 strengthening 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. 3 is an enlarged cross-sectional view of a conventional permeate flow path material formed of a single tricot knitted fabric, and FIG. 4 is an enlarged cross-sectional view of a conventional permeate flow path material formed of a double tricot knitted fabric.

As shown in FIG. 3, in a permeate flow path member 10 made of a single tricot knitted fabric, a plurality of mutually parallel grooves 12 are formed on one side as permeate flow paths. Further, as shown in FIG. 4, in the permeate flow path material 11 made of a double tricot knitted fabric, a plurality of mutually parallel grooves 12 are formed on both sides as permeate flow paths.

However, when the permeated liquid flow path material 10 shown in FIG. 3 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. Similarly, when the permeated liquid channel material 11 shown in FIG.
As shown in (1), the separation membrane 2 is depressed in the groove 12 during operation. As described above, when the permeated liquid channel material 10 of FIG. 3 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 channel 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 comprises a bag-shaped separation membrane having a permeated liquid flow path material inside wound on the outer peripheral surface of a perforated hollow tube. In the spiral separation membrane element in which the permeated liquid flows along the permeated liquid flow path material, a plurality of flow paths are provided inside the permeated liquid flow path material.

In the spiral type separation membrane element according to the present invention, since a plurality of flow paths are provided inside the permeate flow path material, the flow paths are not closed by the separation membrane, and the flow path resistance is reduced. Does not increase. Also, since there is no groove serving as a flow channel on the surface of the permeate flow channel material that the separation membrane contacts,
Even if the pressure in the undiluted liquid flow path is higher than the pressure in the permeated liquid flow path, the separation membrane is not deformed and the separation membrane is not damaged. Therefore, the initial separation membrane performance can be maintained.

It is preferable that the plurality of flow paths extend along the flow direction of the permeated liquid. This allows the permeate in the flow path to flow quickly. Therefore, the flow path resistance is reduced.

Preferably, the plurality of flow paths extend substantially parallel to each other. Thereby, the permeated liquids flowing through the plurality of flow paths all flow in the same direction. This allows the permeated liquid to efficiently flow through the flow channel.

The permeate flow path material is formed by stacking two permeate liquid flow path material elements having a plurality of grooves on one surface such that the plurality of grooves face each other. It is preferable to be constituted by a plurality of opposing grooves of the permeated liquid channel material element. As a result, the existing permeate flow path material can be used as the permeate flow path material element, so that the permeate flow path material can be easily manufactured.

Preferably, each of the two permeate flow path material elements is made of a knitted fabric. Thereby, a groove can be easily provided in the permeate flow path material element. The knitted fabric may consist of a tricot knitted fabric. In this case, the flow path with low flow resistance can be easily formed by the continuous linear groove of the tricot knitted fabric.

It is preferable that the plurality of flow paths extend continuously from the side of the perforated hollow tube to the side of the outer peripheral portion.
In this case, the permeate flows through a continuous flow path without obstacles from the flow path start point to the flow end point. Therefore, the flow path resistance is reduced.

It is preferable that the plurality of flow paths have a linear shape. Thereby, the length of the flow path is minimized, and the flow path resistance is reduced.

[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 is obtained by superposing the separation membrane 2 on both sides of a permeate flow path material 3 composed of two permeate flow path material elements 10a and bonding three sides. A bag-like membrane 4 is formed, and an opening of the bag-like membrane 4 is attached to a liquid collecting tube 5 formed of a perforated hollow tube.
In addition, it is configured by spirally winding the outer peripheral surface of the liquid collection tube 5.

The permeate flow path material element 10a is provided with a linear groove 12 and the permeate liquid flow path material element 10a is extended in a direction perpendicular to the axial direction of the liquid collection tube 5.
a is arranged. The groove 12 extends from the side on the liquid collection tube 5 side to the side on the outer peripheral side.

FIG. 2 is an enlarged sectional view of the permeate flow path material of the spiral separation membrane element of FIG.

The permeate flow path member 3 shown in FIG. 2 is formed from two permeate liquid flow path material elements 10a. Permeate flow path material element 10
A plurality of mutually parallel groove portions 12 are formed on one surface of a, and two permeate liquid flow path material elements 12 are overlapped so that the groove portions 12 face each other. In this way,
The permeated liquid flow path member 3 has two internal grooves 1 through two grooves 12.
3 is formed.

As the permeated liquid passage material element 10a of this embodiment,
A single tricot knitted fabric impregnated with epoxy resin and reinforced is used. The material of the single tricot knit is particularly limited as long as it retains a shape usable as the permeate flow path material element 10a and has little elution of components with respect to the pressure applied to the single tricot knit. is not. For example, fibers of polyamide type, polyester type, polyacrylonitrile type, polyolefin type, polyvinyl chloride type, polyvinylidene chloride type, polyfluoroethylene type, carbon and the like can be mentioned. Considering the ease of processing and the like, it is preferable to use polyester fibers.

During operation of the spiral separation membrane module (not shown), as shown in FIG. 1, the stock solution 7 supplied from one end face of the spiral separation membrane element 1 into the spiral 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. Further, in the process in which the stock solution 7 flows inside the spiral type separation membrane element 1, the permeated liquid 8 permeating the separation membrane 2 passes through the internal flow path 13 provided inside the permeated liquid flow path material 3 in FIG. Flows into the liquid collecting tube 5 of FIG.
The liquid is discharged from the end of the liquid collection tube 5.

Since the internal flow path 13 of the permeate flow path material 3 does not directly contact the separation membrane 2, even in the reverse osmosis membrane separation operation where the pressure of the raw liquid flow path becomes higher than the pressure of the permeate flow path, Membrane 2
Does not block the permeate flow path. Therefore, the flow path resistance does not increase. Further, since there is no groove in a portion where the separation film 2 contacts, the separation film 2 is not deformed. Therefore, 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 internal flow path 13 is formed by the mutually parallel grooves 12 of the permeated liquid flow path material element 10a, the permeated liquid flowing through the plurality of internal flow paths 13 is all in the same direction. Flows. Therefore, the permeated liquid can flow efficiently.

In this embodiment, the internal flow path 13 is
Since the permeated liquid flow path member 3 is disposed so as to extend in the axial direction and the vertical direction, the flow path resistance of the internal flow path 13 is further reduced.

A tricot knit having a linear groove is used as the permeate flow path material element 10a.
Reference numeral 2 continuously extends from the side on the liquid collection tube 5 side to the side on the outer peripheral portion side. Therefore, the internal flow path 13 is the shortest flow path without any obstacle from the flow start point of the permeated liquid to the side on the liquid collection tube 5 side. Therefore, the flow path resistance of the internal flow path 13 is reduced.

Since the existing single tricot knit having a groove on one side can be used as the permeate passage material element 10a, the permeate passage material 3 can be easily manufactured.

In the above example, the permeate flow path material 3 having the internal flow path 13 is formed by overlapping two permeate flow path material elements 10a each having the groove 12 on one surface. The permeate flow path material having the internal flow path 3 may be formed by another method.

[0034]

Example 1 A permeate flow path member 3 composed of two permeate flow path material elements 10a shown in FIG. 2 was produced. Reverse osmosis membranes were arranged on both surfaces of the permeated liquid flow path material 3, and were set in a flow path resistance measuring instrument to measure flow path resistance. The permeated liquid channel material element 10a has a yarn diameter of 70 denier and a wale of 38 denier.
It was formed by impregnating a single tricot knitted fabric having a number of books / inch and a course of 45 / inch with an epoxy resin. Then, 1 to 10 MPa of static pressure water was added at a temperature of 25 ° C., and the flow resistance was measured.

Comparative Example 1 A single permeate flow path material element 10a similar to that of Example 1 was used, and a reverse osmosis membrane was disposed on both surfaces of the permeate flow path material element 10a. did.
Then, the channel resistance was measured under the same test conditions as in Example 1.

[0036]

[Table 1]

Table 1 shows the measurement results of the flow channel resistance of Example 1 and Comparative Example 1. In Example 1, it was found that even if the pressure increased, the flow path resistance did not increase so much, and the flow path inside the flow path material was secured without being crushed. On the other hand, in Comparative Example 1, the flow path resistance sharply increased as the pressure increased.

Embodiment 2 A permeate flow path member 3 composed of two permeate flow path material elements 10a shown in FIG. 2 is prepared, and a reverse osmosis membrane is installed on one surface of the permeate liquid flow path member 3. did. The permeated liquid channel material element 10a has a yarn diameter of 70 denier and a wale of 38 denier.
It was formed by impregnating a single tricot knitted fabric having a number of books / inch and a course of 45 / inch with an epoxy resin.

A 5.8% saline solution was pressurized to 9 MPa, the flow rate on the outlet side was set at 5 L / min, the temperature was set at 25 ° C., and the hydrogen ion concentration (pH) was set at 7, to perform a reverse osmosis membrane permeation experiment.
As for the reverse osmosis membrane performance 60 minutes after the start of operation, the rejection was 99.
At 7%, the amount of permeated water was 0.7 m ³ / m ² / day. After the experiment, the surface of the reverse osmosis membrane was not observed after the depression into the permeate flow path material, and no damage was observed.

COMPARATIVE EXAMPLE 2 One permeate flow path material element 10a of Example 2 was used, and the groove 12 of the permeate flow path material element 10a was used.
A reverse osmosis membrane was placed on the surface having. Then, a reverse osmosis membrane permeation experiment was performed under the same conditions as in Example 2.

With respect to the reverse osmosis membrane performance 60 minutes after the start of the operation, the rejection was 99.5% and the amount of permeated water was 0.5 m ³ / m ² / day. On the surface of the reverse osmosis membrane after the experiment, there was a trace of the depression of the permeated liquid channel material into the groove, and damage to the membrane was observed.

Example 2 and Comparative Example 2 use the same reverse osmosis membrane and differ only in the permeate flow path material. The lower rejection rate 60 minutes after the start of operation of Comparative Example 2 than that of Example 2 is due to the fact that the reverse osmosis membrane was depressed and damaged in the groove 12 of the permeate flow path material element 10a, The permeated water amount is low because the reverse osmosis membrane is depressed into the groove 12 to block the flow path of the permeated liquid and increase the flow path resistance.

As described above, according to the present invention, it is possible to prevent the separation membrane from sinking into the groove of the permeate flow path 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 an enlarged sectional view of a permeate flow path material of the spiral separation membrane element of FIG.

FIG. 3 is an enlarged cross-sectional view of a permeated liquid channel material made of a conventional single tricot knitted fabric.

FIG. 4 is an enlarged cross-sectional view of a permeated liquid flow path material made of a conventional double tricot knitted fabric.

FIG. 5 is a view for explaining a problem when the permeated liquid flow path material of FIG. 3 is used for a spiral type separation membrane element.

FIG. 6 is a diagram for explaining a problem when the permeated liquid channel material of FIG. 4 is used for a spiral type separation membrane element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral-type separation membrane element 2 Separation membrane 3 Permeate liquid flow path material 4 Bag-shaped membrane 5 Liquid collection pipe 10a Permeate liquid flow path material element 12 Groove part 13 Internal flow path

Claims (8)

[Claims] 1. A spiral type membrane in which a bag-shaped separation membrane provided with a permeate flow path material inside is wound around the outer peripheral surface of a perforated hollow tube, and the permeate flows along the permeate flow path material. A spiral separation membrane element, wherein a plurality of flow paths are provided inside the permeate flow path material in the separation membrane element. 2. The spiral separation membrane element according to claim 1, wherein the plurality of flow paths extend along a flow direction of the permeated liquid. 3. The spiral separation membrane element according to claim 1, wherein the plurality of flow paths extend substantially in parallel with each other. 4. The permeate flow path material is formed by stacking two permeate flow path material elements having a plurality of grooves on one surface such that the plurality of grooves face each other. The passage is constituted by a plurality of opposed grooves of the two permeate flow path material elements.
The spiral separation membrane element according to any one of the above. 5. The spiral separation membrane element according to claim 4, wherein each of said two permeate flow path material elements is made of a knitted fabric. 6. The spiral separation membrane element according to claim 5, wherein the knitted fabric is made of a tricot knitted fabric. 7. The method according to claim 1, wherein the plurality of flow paths continuously extend from a side of the perforated hollow tube to a side of an outer peripheral portion. Spiral type separation membrane element. 8. The spiral-type separation membrane element according to claim 1, wherein the plurality of flow paths have a linear shape.