JP2000334272A - Spiral type separation membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spiral type separation membrane element hardly generating the clogging of an original liquid flow passage and prevented in the lowering of the quantity of the permeated liquid due to the concentration polarity along the membrane surface of the separation membrane. SOLUTION: A bag like separation membrane 2 and an original flow passage material 6 are wound around the outer periphery of a water collecting pipe 5 to laminate the original flow passage material 6 on one surface side of the bag like separation membrane 2. The original water flow passage material 6 is composed of a sheet like material and plural hemispherical projected parts 6 are formed on both surfaces. The plural hemispherical projected parts 61 are arranged in plural rows parallel to the axial direction of the water collecting pipe 5. A hemispherical recessed part 62 are formed on the rear side of each hemispherical projected part 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spiral separation membrane element used for a membrane separation device such as a reverse osmosis membrane separation device, an ultrafiltration device and a microfiltration device.

[0002]

2. Description of the Related Art A separation 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] As a separation membrane module used for such a filtration, a spiral type module is used depending on the use and purpose.
There are various types of separation membrane modules such as a hollow fiber type, a plate and frame type, a rotating flat membrane type, and a flat membrane lamination type. Among them, the spiral-type separation membrane module uses a sheet-like separation membrane whose active thinning is relatively easy, 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.
In this spiral type separation membrane element, a permeated water flow path material is inserted inside a bag-shaped separation membrane, and the raw water flow path material is overlapped on one surface side of the bag-shaped separation membrane. The opening is attached to a water collecting pipe formed of a perforated hollow pipe, and a bag-shaped separation membrane and a raw water flow path material are spirally wound around the outer peripheral surface of the water collecting pipe.

The raw water flowing from one end face of the spiral type separation membrane element flows along the raw water flow path material outside the bag-shaped separation membrane, and a part of the raw water permeates through the separation membrane to become permeated water. After flowing along the water channel material, it flows into the collecting pipe and is taken out from the opening end of the collecting pipe. The raw water that has not passed through the separation membrane is discharged from the other end face of the spiral separation membrane element as concentrated water. In such a spiral-type separation membrane element, a flow path through which raw water passes is formed between the bag-shaped separation membranes by the raw water flow path material, and the permeated water permeated into the bag-shaped separation membrane by the permeated water flow path material. Is formed.

In a conventional spiral type separation membrane element, a net-like raw water flow path material is used. Also, a raw water flow path material having a plurality of figure-eight projections formed in a row on the surface has been proposed. In addition, for example,
Japanese Patent Publication No. 98272 discloses a corrugated raw water flow path material (so-called corrugated spacer).

[0007]

In the above-mentioned conventional spiral-type separation membrane element, when raw water containing a suspended substance is supplied, the suspended substance is captured by a net-shaped raw water flow path material, and the raw material is suspended in the net. The water channel is likely to be blocked by suspended matter. Even in the case of using the raw water flow path material in which the figure-shaped projections are formed in a row, the suspended substance is captured at the ends of the figure-shaped projections, and the raw water flow path is closed by the suspended substance.

When a corrugated raw water flow path material is used, suspended raw materials are relatively hard to be trapped in the raw water flow path.
However, since multiple raw water channels are independent one by one,
Once a suspended substance is clogged in the raw water flow path, the raw water flow path is completely blocked.

Therefore, in the case of using a net-shaped raw water flow path material, a raw water flow path material having an octagonal projection, and a corrugated raw water flow path material, after removing suspended substances in raw water in advance. It is necessary to supply to the spiral type separation membrane element, and complicated pretreatment must be performed.

In particular, in a spiral separation membrane element using a corrugated raw water flow path material, a straight raw water flow path penetrates from the raw water inlet to the raw water outlet, and the raw water flow between the separation membranes. There are few factors that agitate the flow. Therefore, the flow of the raw water tends to be laminar, and concentration polarization occurs along the membrane surface of the separation membrane, and the amount of permeated water tends to decrease. Therefore, in the case of using a corrugated raw water flow path material, a predetermined amount of permeated water can be obtained unless raw water flows at high speed between the separation membranes as compared with the case of using a net-shaped raw water flow path material. Can not. As a result, power costs are increased.

An object of the present invention is to provide a spiral-type separation membrane element in which a stock solution flow path is hardly blocked and a decrease in the amount of permeate due to concentration polarization along the membrane surface of the separation membrane is prevented.

[0012]

Means for Solving the Problems and Effects of the Invention A spiral separation membrane element according to the present invention comprises a bag-shaped separation membrane wound around the outer peripheral surface of a perforated hollow tube together with a stock solution flow path material. In the mold separation membrane element, the stock solution channel material is made of a sheet material having a plurality of substantially spherical convex portions on at least one surface.

In the separation membrane element according to the present invention, the stock solution flow path is formed by a stock solution flow path material made of a sheet-like material having a plurality of substantially spherical convex portions on at least one surface. As a result, the stock solution flowing along the surface of the separation membrane is stirred at the substantially spherical convex portion of the stock solution channel material, and the concentration polarization along the surface of the separation membrane is eliminated. As a result, the permeation speed increases, and the amount of permeate increases sufficiently.

Further, since the plurality of projections on the surface of the stock solution channel material are substantially spherical, suspended substances contained in the stock solution are not easily captured by the plurality of projections. Thereby, the blockage of the stock solution flow path is prevented. Even if the suspended matter is captured by the projections, the respective stock solution channels are not independent and are connected to each other, so that the clogging of the suspended matter is prevented from expanding.

Furthermore, since the plurality of projections of the stock solution flow path material come into contact with the membrane surface of the separation membrane at a spherical point, damage to the membrane surface can be suppressed to a minimum, and the effective membrane area of the separation membrane can be reduced. Can be maximized.

The sheet material may have a plurality of substantially spherical convex portions on both surfaces. In this case, a stock solution flow path is formed on both sides of the stock solution flow path material.

The plurality of projections may be regularly arranged.
Thereby, a regular stock solution flow path is formed, and the pressure loss in the stock solution flow path is reduced.

The plurality of projections may be arranged in a plurality of rows parallel to the axial direction of the perforated hollow tube. As a result, the stock solution easily flows in a direction parallel to the axial direction of the perforated hollow tube, and the pressure loss in the stock solution flow path can be sufficiently reduced.

The sheet material may have a plurality of substantially spherical concave portions on at least one surface. In this case, the stock solution is further stirred by the plurality of recesses.

It is preferable that the diameter of the planar shape of the plurality of projections is 1 mm or more and 10 mm or less. As a result, a sufficient stirring effect of the stock solution is obtained, and the flow path resistance is sufficiently reduced.

The height of the plurality of projections is 0.1 mm or more and 2.0
mm or less. Thereby, the blockage of the stock solution flow channel is sufficiently prevented while securing a sufficient membrane area.

[0022]

FIG. 1 is a partially cutaway perspective view showing an example of a spiral type separation membrane element according to the present invention.
Is an exploded cross-sectional view of the spiral separation membrane element of FIG.
FIG. 3 is a sectional view of the spiral separation membrane element of FIG.

1 to 3, the water collecting pipe 5 is provided with a plurality of holes 5a. A mesh-shaped permeated water flow path material (permeated water spacer) 3 is inserted inside the bag-shaped separation membrane 2. As shown in FIG. 2, a water collecting pipe 5 is inserted into the central portion 2a of the bag-shaped separation membrane 2. The bag-shaped separation membrane 2 and the raw water flow path material 6 are wound around the outer peripheral surface of the water collecting pipe 5 in a state where a raw water flow path material (raw water spacer) 6 described later is superimposed on one surface side of the bag-shaped separation membrane 2. You. Thereby, the spiral separation membrane element 1 is configured.

FIG. 4A is a plan view showing an example of a raw water flow path material 6 used in the spiral separation membrane element 1 shown in FIGS. 1 to 3, and FIG. 4B is a raw water flow material shown in FIG. X of road material 6
-X-ray sectional view, FIG. 4 (c) is the raw water flow path material 6 of FIG. 4 (a).
5 is a sectional view taken along line YY of FIG. 5A is a plan view showing another example of the raw water flow path material 6 used in the spiral separation membrane element 1 of FIGS. 1 to 3, and FIG. 5B is a raw water flow path of FIG. 5A is a cross-sectional view of the material 6 taken along the line AA, and FIG.
FIG. 3 is a sectional view taken along line BB of the raw water flow path material 6 of FIG.

As shown in FIGS. 4 and 5, the raw water flow path member 6 is made of a sheet material, and has a plurality of hemispherical convex portions 61 formed on both surfaces. The plurality of hemispherical protrusions 61 are arranged in a plurality of rows along the direction of arrow C. On the back side of each hemispherical convex portion 61, a hemispherical concave portion 62 having a smaller diameter than the convex portion 61 is formed. Thus, the uneven structure in which the plurality of hemispherical convex portions 61 and concave portions 62 are regularly arranged is called a dimple structure.

The height H of the hemispherical projection 61 is equal to or less than the diameter D of the planar circle of the hemispherical projection 61. If the diameter D of the plane-shaped circle of the hemispherical projection 61 is smaller than 1 mm, it is difficult to obtain a sufficient stirring effect of the raw water. On the other hand, if the diameter D of the plane-shaped circle of the hemispherical convex portion 61 is larger than 10 mm, the flow path resistance becomes high, a sufficient linear velocity of the raw water cannot be obtained, and the cake due to the suspended solids in the raw water may be formed. It is easy to form. Therefore, it is preferable that the diameter D of the planar shape circle of the hemispherical convex portion 61 is 1 mm or more and 10 mm or less.

If the height H of the hemispherical projection 61 is smaller than 0.1 mm, the separation membranes 2 come into contact with each other and the flow path becomes small, and the flow path is easily blocked by suspended substances in raw water. Become. If the height H of the hemispherical convex portion 61 is larger than 2.0 mm, the volume occupied by the raw water flow path material 6 in the spiral separation membrane element 1 is increased, and the membrane area per element is reduced. Therefore, it is preferable that the height H of the hemispherical convex portion 61 is 0.1 mm or more and 2.0 mm or less.

The raw water flow path material 6 has a thickness of, for example, 0.0
It can be easily manufactured by vacuum forming a sheet of synthetic resin such as polyvinyl chloride, cellulose acetate, polypropylene, polyethylene, polystyrene and the like having a thickness of about 5 to 0.5 mm.

In the raw water flow path member 6 shown in FIG. 4, a plurality of hemispherical projections 61 are provided alternately in two rows on the front side and the back side. In addition, each convex portion 61 in two adjacent rows is shifted by half a cycle in the direction of arrow C. Thus, a plurality of raw water flow paths meandering in a direction parallel to the arrow C are formed.

In the raw water flow path member 6 shown in FIG. 5, a plurality of hemispherical projections 61 are alternately provided on the front side and the back side one by one. The plurality of hemispherical convex portions 61 on the surface side
Also aligned in the direction perpendicular to arrow C. Similarly, the plurality of hemispherical convex portions 61 on the back side are aligned in a direction perpendicular to the arrow C. Thereby, a plurality of linear raw water flow paths are formed in a direction parallel to the arrow C.

The raw water flow path material 6 shown in FIGS.
Are arranged so that the direction of arrow C is parallel to the axial direction of the water collecting pipe 5 so that the flow of raw water is formed along the direction of.

As shown in FIG. 1, raw water 7 is supplied from one end face of the spiral type separation membrane element 1. In this case, the raw water 7 flows between the bag-shaped separation membranes 2 along both surfaces of the raw water flow path member 6, and is discharged as concentrated water 9 from the other end face side of the spiral type separation membrane element 1. In the meantime, a part of the raw water 7 permeates through the separation membrane 2 to become permeated water 8 and flows into the bag-like separation membrane 2. The permeated water 8 flowing into the bag-shaped separation membrane 2 flows toward the water collecting pipe 5 along the permeated water flow path material 3, and then passes through the hole 5 a of the water collecting pipe 5 to enter the water collecting pipe 5. It flows in and is taken out from the end of the water collecting pipe 5.

In this case, the raw water 7 flowing along the surface of the separation membrane 2 is stirred by the dimple structure of the raw water flow path member 6. Thereby, concentration polarization in the raw water flow path is eliminated, and the transmission speed is increased. As a result, a sufficiently high amount of permeated water can be obtained without flowing raw water between the separation membranes 2 at high speed. Therefore, power costs can be reduced.

The plurality of convex portions 6 on the surface of the raw water flow path member 6
Since 1 has a hemispherical shape, the suspended substance contained in the raw water is not easily captured by the plurality of projections 61. Thereby,
Blockage of the raw water flow path is prevented.

Furthermore, since the plurality of hemispherical projections 61 of the raw water flow path member 6 come into contact with the membrane surface of the separation membrane 2 at spherical points, damage to the membrane surface can be suppressed to a minimum. The effective membrane area of the separation membrane 2 can be maximized.

When the raw water flow path member 6 shown in FIG. 4 is used, the raw water flows so as to meander in the axial direction of the water collecting pipe 5, so that the raw water stirring effect is further enhanced. On the other hand, when the raw water flow path material 6 of FIG. 5 is used, since the raw water flows linearly in parallel with the axial direction of the water collecting pipe 5, the flow path resistance is further reduced.

[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 exploded sectional view of the spiral separation membrane element of FIG.

FIG. 3 is a sectional view of the spiral separation membrane element of FIG. 1;

FIG. 4 is a plan view, a cross-sectional view taken along line XX, and a cross-sectional view taken along line YY of an example of a raw water flow path material used in the spiral separation membrane element shown in FIGS.

5 is a plan view, an AA line cross-sectional view, and a BB line cross-sectional view showing another example of the raw water flow path material used for the spiral separation membrane element of FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral-type separation membrane element 2 Separation membrane 3 Permeate water channel material 5 Water collecting pipe 6 Raw water channel material 7 Raw water 8 Permeate 9 Concentrated water

Claims (7)

[Claims] 1. A spiral-type separation membrane element in which a bag-shaped separation membrane is wound around an outer peripheral surface of a perforated hollow tube together with a raw liquid flow path material, wherein the raw liquid flow path material has a substantially spherical shape on at least one surface. A spiral separation membrane element comprising a sheet-like material having a plurality of projections. 2. The spiral separation membrane element according to claim 1, wherein the sheet material has a plurality of substantially spherical convex portions on both surfaces. 3. The spiral separation membrane element according to claim 1, wherein the plurality of projections are regularly arranged. 4. The spiral separation membrane element according to claim 3, wherein the plurality of projections are arranged in a plurality of rows parallel to an axial direction of the perforated hollow tube. 5. The spiral separation membrane element according to claim 1, wherein said sheet-shaped material has a plurality of substantially spherical concave portions on at least one surface. 6. The diameter of a plane shape of the plurality of projections is 1 m.
m and 10 mm or less.
5. The spiral separation membrane element according to any one of the above items 5. 7. The spiral separation membrane element according to claim 1, wherein the height of the plurality of projections is 0.1 mm or more and 2.0 mm or less.