JPH11114381A - Spiral type membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the subject element inexpensive and to increase an effective membrane area by simplifying constitutional elements. SOLUTION: This membrane element is constituted of forming many hollow holes 4 in the inside of a plane membrane 2 out using a base material by cylindrically penetrating through it, and spirally winding the plane membrane 2 on the outer peripheral surface of an infiltration collecting pipes such that openings at a membrane end surface 2b become an outer peripheral surface side. Many grooves 5 extending along the infiltration collecting pipes are formed at least on one side surface of the plane membrane 2. A space becoming an original fluid flow path is formed between the surfaces of the plane membrane 2 wound mutually in contact with the grooves 5. Also the hollow holes 4 constitute flow paths of the infiltration fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Separation membrane modules have been used for separating specific components contained in liquids and gases using separation membrane technology. For example, separation membrane modules include reverse osmosis membrane technology to separate salts in water, ultrafiltration membrane technology to separate bacterial cells dispersed in liquid, and microfiltration to separate solid turbid components in turbid liquid. It is used for a membrane technology or a gas separation membrane technology for separating a specific gas in a gas.

[0003] A separation membrane module used in such a separation membrane technology is configured so as to increase the membrane area by bundling a large number of separation membrane elements having various shapes. There are various types of modules such as a hollow fiber type, a plate and frame type, a rotating flat membrane type, and a flat membrane laminated type. Among them, the spiral-type separation membrane module uses a sheet-like separation membrane (hereinafter, referred to as a flat membrane), which is relatively easy to be made into an active thin film, and has excellent pressure resistance and can be manufactured relatively inexpensively. It is widely used for reverse osmosis membrane technology and gas separation membrane technology that require a composite membrane.

[0004] The spiral type separation membrane module forms a laminated membrane by laminating flat membranes on both surfaces of a permeated fluid channel material,
Further, a spiral-type membrane element is provided in which the laminated film and the raw fluid flow path material are laminated and spirally wound around the outer peripheral surface of the water collecting pipe.

[0005]

In recent years, as the market for separation membranes has expanded, the demand for membrane separation devices has increased. For this reason, a spiral-type membrane element which is less expensive and has excellent water permeability is demanded.

On the other hand, there has been proposed an example in which the structure of a spiral type membrane element is simplified to reduce the cost. For example, Japanese Patent Application Laid-Open No. 59-82906 discloses a spiral-type membrane element in which a number of hollow holes are formed in a flat membrane in which a base material such as a woven fabric or a non-woven fabric is omitted to form a permeate fluid flow path. A spiral type separation membrane module is disclosed. In this spiral type membrane element, cost reduction is achieved by omitting the base material in the flat membrane in addition to omitting the permeate fluid flow path material.

However, in the above-mentioned spiral type membrane element, the raw fluid flow path material laminated on the flat membrane surface is still used, thereby securing the raw fluid flow path. For this reason, there is room for further simplifying the configuration of the spiral membrane element and reducing the cost.

Japanese Unexamined Patent Publication (Kokai) No. 63-296804 discloses a flat membrane laminated type separation membrane in which a number of fine projections are formed on a flat membrane surface to omit a raw fluid flow path material and a permeate fluid flow path material. A module is disclosed. However,
In a flat membrane stack type separation membrane module, there is a limit to improving the effective membrane area per unit volume.

Further, Japanese Patent Application Laid-Open No. 63-69503 discloses a spiral membrane element in which a flat membrane having a plurality of grooves provided in a predetermined direction on the surface of the flat membrane is laminated and spirally wound around the outer periphery of a water collecting pipe. Is disclosed. In this spiral membrane element, a permeate fluid flow path is formed between two flat membranes by laminating two flat membranes having grooves formed therein, and the permeate fluid flow path material and the raw fluid flow path material are omitted. I have. Thereby, the effective film area per unit volume is increased, and miniaturization and cost reduction are achieved. However, it is desired to further reduce the cost of such a spiral membrane element.

It is an object of the present invention to provide a spiral-type membrane element which can reduce the cost by simplifying the components and can increase the effective membrane area.

[0011]

Means for Solving the Problems and Effects of the Invention A spiral membrane element according to the present invention is a spiral membrane element in which a separation membrane is spirally wound around the perimeter of a perforated hollow tube. Has a plurality of hollow passages that have irregularities on at least one membrane surface, extend in the membrane in a direction parallel to the membrane surface, and open to the end face on the perforated hollow tube side.

In the spiral type membrane element according to the present invention, since at least one surface of the separation membrane is formed with irregularities, a space is formed between the surfaces of the separation membrane wound so as to overlap. This space forms a raw fluid flow path. The raw fluid flows through the raw fluid channel formed by the irregularities. Further, the hollow passage formed inside the separation membrane constitutes a permeated fluid passage. A part of the raw fluid flowing through the raw fluid flow path passes through the separation membrane and flows into the hollow passage. Then, it flows through the hollow passage and is guided to the perforated hollow tube.

As described above, the unevenness on the surface of the separation membrane constitutes the raw fluid flow path, and the hollow passage in the membrane constitutes the permeated fluid flow path. There is no need to provide a fluid flow path member, whereby the components are simplified, and the cost of the spiral membrane element can be reduced.

In addition, by forming irregularities on at least one surface of the separation membrane, the effective membrane area of the separation membrane is increased, and the permeation flow rate can be increased.

In particular, the unevenness is preferably a plurality of grooves extending parallel to the axial direction of the perforated hollow tube. This allows
The raw fluid can flow at low resistance along the plurality of grooves in the axial direction of the perforated hollow tube on the surface of the spirally wound separation membrane. As a result, a high permeation flow rate can be obtained at a low operation pressure.

In particular, it is preferable that the unevenness is formed on both film surfaces of the separation membrane, and that the shape of the unevenness on one film surface is different from the shape of the unevenness on the other film surface.

In this case, the shape of the irregularities on the surface of one of the separation membranes wound so as to overlap each other is different from the shape of the irregularities on the surface of the other membrane. As a result, a space is formed between the surfaces of the wound separation membrane by irregularities having different shapes, and this space constitutes a raw fluid flow path. Thereby, the raw fluid flow path can be secured without using the raw fluid flow path material, and the cost of the spiral membrane element can be reduced.

In particular, it is preferable that one separation membrane is provided, and one separation membrane is wound around the outer periphery of the perforated hollow tube so that one membrane surface of the separation membrane is in contact with the other membrane surface.

In this case, since a single separation membrane can be wound around the outer periphery of the perforated hollow tube to form a spiral-type membrane element, the production becomes easy. In addition, by winding the separation membrane without interposing the raw fluid flow path material, the raw fluid flow path due to unevenness between one membrane surface and the other membrane surface of the separation membrane that is wound in contact therewith. Is configured. With such a structure, a low-cost spiral-type membrane element in which the raw fluid flow path material is omitted can be obtained.

In particular, a plurality of separation membranes are provided, and the plurality of separation membranes are wound around the perimeter of a perforated hollow tube such that the surface of one of the separation membranes is in contact with the surface of the other separation membrane. Is preferred.

By winding a plurality of separation membranes around the perimeter of a perforated hollow tube, the length of the hollow passage formed in the membrane of each separation membrane is reduced, and the flow resistance of the permeated fluid is reduced. Can be. Also, by winding a plurality of separation membranes without using a raw fluid flow path material, a raw fluid flow path is formed between one membrane surface of the separation membranes in contact with each other and the other membrane surface of the other separation membrane. Is done. Thereby, a low-cost spiral-type membrane element in which the raw fluid flow path material is omitted can be obtained.

In particular, it is preferable that the hollow passage is a passage having a substantially circular cross section extending in the circumferential direction of the perforated hollow tube.

In this case, the operating pressure applied at the time of the separation operation using the spiral type membrane element acts on the inner peripheral surface of the hollow passage almost uniformly, so that the shape of the hollow passage is easily maintained, The pressure resistance of the separation membrane is improved.

[0024]

FIG. 1 is a perspective view showing a state in which a part of a spiral type membrane element according to the present invention is unwound.
FIG. 2 is an enlarged perspective view of a flat membrane of the spiral membrane element of FIG. 1, and FIG. 3 is a schematic cross-sectional view of the spiral membrane element of FIG.

The spiral type membrane element 1 shown in FIG.
Is configured by winding the flat membrane 2 around the outer peripheral surface of a permeate collecting pipe 3 composed of a perforated hollow pipe having a plurality of holes on the peripheral wall surface.

As shown in FIG. 2, a plurality of hollow holes 4 are formed inside the flat membrane 2. The hollow hole 4 is formed so as to penetrate from the one membrane end face 2a of the flat membrane 2 to the other membrane end face 2b side, and forms a permeate fluid flow path. The cross-sectional shape of the hollow hole 4 is preferably substantially circular. In this case, the operating pressure applied at the time of the separating operation uniformly acts on the outer peripheral wall surface of the hollow hole 4, and the internal space of the hollow hole 4 is easily maintained. Also,
The diameter of the hollow hole 4 is appropriately selected according to the operating pressure and the properties of the processing solution.

A large number of grooves 5 are formed on one or both of the upper surface 2c and the lower surface 2d of the flat film 2.
The grooves 5 are formed so as to be aligned in a direction orthogonal to the hollow holes 4, and each groove 5 has a V-shaped cross section. For example,
As shown in FIG. 3, when the groove 5 is formed only on the lower surface 2d of the flat film 2, the upper surface 2c of the flat film 2 is flat. Then, when the flat membrane 2 is spirally wound, the inner flat membrane 2 is wound.
The lower surface 2d of the outer flat film 2 is in contact with the upper surface 2c. Thus, the raw fluid flow path 6 is formed between the upper surface 2c and the lower surface 2d of the flat membrane 2 by the groove 5. This raw fluid flow path 6
It is configured along the transmission collecting pipe 3.

When the groove 5 is formed on both the upper surface 2c and the lower surface 2d of the flat film 2, the groove 5 on the upper surface 2c and the lower surface 2d are formed.
The groove 5 is formed in a different shape. For example, upper surface 2
A V-shaped groove is formed on the c side, and a rectangular groove is formed on the lower surface 2d side. Alternatively, the type of the cross-sectional shape of the groove 5 on the upper surface 2c and the groove 5 on the lower surface 2d are made the same, and the size of the groove, for example, in the case of a V-shaped groove, the width and depth of the V-shaped groove are made different.

Further, at least the upper surface 2c and the lower surface 2d of the flat membrane 2 and the inner surface of the hollow hole 4 are subjected to an active layer treatment.

In the active layer, for example,
Various active layers exist for each of microfiltration membranes, ultrafiltration membranes, reverse osmosis filtration membranes, gas separation membranes, and the like.
It is formed by various kinds of active layer processes.

One is a method of forming a dense layer composed only of the same material as the flat film main body, and only the surface portion is adapted for the purpose of separation. The other is a method of forming a thin film dense layer composed of a completely different material. This is a method of coating.

The former is generally applied to microfiltration membranes and ultrafiltration membranes which do not require relatively high density, and the latter is generally applied to high density filtration, for example, reverse osmosis membranes. And gas separation membranes. The separation membrane after the treatment with the active layer is used for an application suitable for each purpose.

FIG. 4 is a schematic cross-sectional view showing the main constituent materials of the spiral type membrane element shown in FIG. FIG.
Shows a state before the flat membrane 2 is wound. As shown in FIG. 4, in the spiral-type membrane element 1, the membrane end faces 2 b of the plurality of flat membranes 2 are adhered to one end of an adhesive sheet 7 via an adhesive 8, and the other end of the adhesive sheet 7 is connected to the transparent collecting pipe 3. Adhered to the surface. A plurality of flat membranes 2 are spirally wound along the outer periphery of the permeation collecting pipe 3. As a result, one opening of the hollow hole 4 in the flat membrane 2 and the hole on the outer peripheral surface of the transmission collecting pipe 3 communicate with each other. The end of the hollow hole 4 on the side of the membrane end face 2a is sealed with a sealing resin.

Here, the hollow holes 4 correspond to hollow passages of the present invention, and the grooves 5 correspond to irregularities. 1, the raw fluid 11 flows into the raw fluid flow path 6 between the surfaces of the overlapping flat membranes 2 from one end side of the cylindrically wound flat membrane 2 in FIG. Flows along. The groove 5 is formed linearly along the axial direction of the transmission collecting pipe 3. Therefore, the raw fluid 11 flows along the groove 5 with a low resistance. The permeated fluid 12 that has passed through the surface of the flat membrane 2 in the flow process flows into the hollow 4, flows through the hollow 4, is guided to the permeation collecting pipe 3, and is taken out. In addition, the concentrated fluid 13, which is concentrated by permeating the solvent in the raw fluid 11, is discharged from the other end of the cylindrical flat membrane 2.

In the spiral membrane element 1 having the above structure, a material and a shape are selected according to a membrane separation operation to be applied.

As a material for the flat membrane 2, for example, when the spiral membrane element 1 is applied to microfiltration,
A porous membrane such as polypropylene, polyethylene, or polysulfone is used.When applied to ultrafiltration, a porous membrane such as polysulfone or polyacrylonitrile is used.When applied to reverse osmosis, a cellulose acetate asymmetric membrane is used. And a polyamide-based composite film. Further, when applied to gas separation, a polyimide asymmetric membrane or a silicone-based composite membrane is used.

Referring to FIG. 2, the shape of flat membrane 2 is such that film thickness δ is 10 μm to 10 mm, diameter d of hollow hole 4 opened at the end face of flat membrane is 10 μm to 8 mm, and one of flat membrane 2 is formed. The total opening area of the plurality of hollow holes 4 opening to the end is selected to be 80% or less of the area of the membrane end face of the flat membrane 2. Further, the step h of the unevenness of the groove 5 is 5 μm to 5 mm, and the groove width p of each groove 5 is 100
It is selected from μm to 10 mm.

Further, referring to FIG. 1, the shape of the spiral type membrane element 1 is selected so that the diameter D of the element after winding the flat membrane 2 is 10 mm to 500 mm and the length of the element is 10 mm to 3 m. You.

Further, the transmission collecting pipe 3 is made of polyethylene,
It is formed from various plastics such as polypropylene, ABS resin and vinyl chloride. In particular, when pressure resistance is required, a glass fiber reinforced plastic or a metal material such as iron or stainless steel is used.

Referring to FIG. 4, adhesive sheet 7 is formed of various plastics such as polyester, polyethylene, and polypropylene. As adhesive 8, epoxy resin-based, urethane resin-based, or phenol resin-based adhesive is used. Can be

Spiral type membrane element 1 according to the present invention
In the above, the flat membrane 2 is composed of a membrane that does not use a base material such as a woven fabric or a nonwoven fabric. In addition, the permeated fluid channel is a flat membrane 2
The raw fluid flow path 6 is formed by the grooves 5 on the surface of the flat membrane 2. This eliminates the need for a base material in the flat membrane, and a raw fluid flow path material and a permeate fluid flow path material for securing the raw fluid flow path and the permeate fluid flow path, thereby reducing the cost of the spiral membrane element. can do.

Further, the formation of the groove 5 on the surface of the flat film 2 increases the surface area of the flat film 2 and increases the effective film area. In addition, unlike the conventional spiral type membrane element, since the raw fluid flow path material is not laminated on the surface of the separation membrane, the portion where the raw fluid flow path material prevents the contact between the raw fluid and the flat membrane 2 is prevented. Disappears. Thereby, in the spiral separation membrane module using the spiral membrane element according to the present invention, the permeation flow rate per unit volume can be increased.

[0043]

EXAMPLES A spiral-type separation membrane module having a spiral-type membrane element of the embodiment having the above-described structure was manufactured under the following conditions, and an experiment was conducted on its water permeability.

(1) Specifications of flat membrane

[0045]

[Table 1]

(2) Specifications of membrane element

[0047]

[Table 2]

The symbols in Tables 1 and 2 are shown in FIG.
And symbols in FIG. Further, for comparison, the element diameter D and the length L in the direction of the permeable collecting tube are equal to the spiral membrane element of the above embodiment,
A flat membrane is laminated on both sides of the permeated water spacer (permeate fluid flow path material) to form an envelope-shaped membrane, and further laminated with the raw water spacer (raw fluid flow path material) to form a spiral around the permeate collecting pipe. A spiral type separation membrane module having a wound spiral type membrane element was produced as a comparative example.

Table 3 shows the specifications of the spiral type separation membrane modules of the example and the comparative example.

[0050]

[Table 3]

Further, the spiral type separation membrane modules of Examples and Comparative Examples were subjected to an evaluation experiment of a desalination operation from tap water under the conditions shown in Table 4.

[0052]

[Table 4]

Table 5 shows the results of the above evaluation experiment.

[0054]

[Table 5]

As shown in Table 5, the spiral membrane element of the example has a larger effective membrane area than the spiral membrane element of the comparative example having the same size. This is because grooves were formed on the surface of the flat membrane of the spiral membrane element of the embodiment. And the amount of permeated water is larger than that of the comparative example due to the increase in the effective membrane area. Thereby, in the spiral membrane element according to the present embodiment, the amount of permeated water per the same volume in the pressure vessel in which the spiral membrane element is stored can be increased as compared with the spiral membrane element of the comparative example.

Further, the spiral membrane element of the embodiment can be manufactured at a lower cost because the base material of the flat membrane, the raw water spacer and the permeated water spacer are omitted as compared with the spiral membrane element of the comparative example. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a part of a spiral type membrane element according to the present invention is unwound.

FIG. 2 is an enlarged perspective view of a flat membrane of the spiral membrane element of FIG. 2;

FIG. 3 is a partial cross-sectional view of the spiral membrane element of FIG. 1;

FIG. 4 is a schematic cross-sectional view showing a main constituent material for winding the spiral membrane element of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral-type membrane element 2 Flat membrane 2a, 2b End face of flat membrane 2c, 2d Upper and lower surfaces of flat membrane 3 Permeable collecting pipe 4 Hollow hole 5 Groove 6 Raw fluid flow path

Claims (6)

[Claims] 1. A spiral-type membrane element in which a separation membrane is spirally wound around an outer periphery of a perforated hollow tube, wherein the separation membrane has irregularities on at least one surface of the membrane, and has a membrane in the membrane. A spiral membrane element having a plurality of hollow passages extending in a direction parallel to the surface and opening at an end face on the side of the perforated hollow tube. 2. The method according to claim 1, wherein the unevenness is a plurality of grooves extending parallel to an axial direction of the perforated hollow tube.
The spiral-type membrane element described in the above. 3. The unevenness is formed on both film surfaces of the separation membrane, and the shape of the unevenness on one film surface is:
3. The spiral membrane element according to claim 1, wherein the shape of the unevenness on the other membrane surface is different. 4. One of the separation membranes is wound around the outer periphery of the perforated hollow tube such that one of the separation membranes is in contact with the other membrane surface. The spiral-type membrane element according to any one of claims 1 to 3, wherein: 5. A plurality of said separation membranes, wherein said plurality of separation membranes are connected to said perforated hollow tube such that one membrane surface of each separation membrane is in contact with the other membrane surface of another of said separation membranes. The spiral membrane element according to any one of claims 1 to 3, wherein the spiral membrane element is wound around the outer periphery. 6. The spiral membrane element according to claim 1, wherein the hollow passage is formed of a passage having a substantially circular cross section and extending in a circumferential direction of the perforated hollow tube.