JPH07155564A - Hollow yarn membrane module and its production - Google Patents

Abstract

PURPOSE:To efficiently scrubbing-clean the whole of a hollow yarn membrane in a module by having >=2 sets of a hollow yarn membrane intertwined material, placing the >=2 sets of the hollow yarn membrane intertwined material mutually in parallel at a fixed interval and integrally fixing the plural intertwined material to the one part of a resin fixing part. CONSTITUTION:This hollow yarn membrane module uses the sheet type hollow yarn membrane intertwined material 1. The distance between the hollow yarn membrane intertwined materials 1 in the module is adjusted to be equal in consideration of uniformly air-bubbling to the whole of the membrane surface at the time of scrubbing cleaning. The distance between the sheets is selected in consideration of the efficiency of the scrubbing cleaning in air bubbling or the like, the prevention of the adjacent hollow yarn membrane intertwined material 1 from the contact and the membrane area per the module. Furthermore, the hollow yarn membranes are prevented to stick and integrate to each other by fixing to >=2 sets of the hollow yarn membrane intertwined material 1 to the resin fixing part 3 of a housing 2 in every piece at the fixed interval.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane module, and more particularly to a hollow fiber membrane module suitable for filtering a liquid having a high pollutant (particularly, an organic matter pollutant) and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, hollow fiber membrane modules have been manufactured using sterile water,
It has been widely used in the field of so-called microfiltration such as the production of drinking water and high-purity water, and the purification of air, but in recent years, it has undergone secondary and tertiary treatment in sewage treatment plants and solid-liquid separation in septic tanks. , Solid-liquid separation of ss (suspended suspended solids) in industrial wastewater, direct filtration of river water in water purification plants, filtration of industrial tap water, filtration of pool water, etc. It has been done in various ways.

However, the hollow fiber membrane modules used in these fields also have a cylindrical shape in which the hollow fiber membranes are arranged concentrically in a circular shape or a concentric circle which has been used in the field of conventional microfiltration. Most were of the type. Further, even if improvements are made, many of them merely change the filling rate or filling form of the hollow fiber membrane.

[0004]

Highly polluted water (for example, ss ≧ 50 ppm, T) is obtained by using a conventional hollow fiber membrane module.
(OC ≧ 100 ppm), when the hollow fiber membranes are adhered (adhered) to each other through the deposits such as organic substances adhered to the surface of the hollow fiber membranes during use, the hollow fiber membranes are integrated. The effective membrane area of the hollow fiber membrane in the module was reduced, and the filtration flow rate was sharply reduced.

In particular, this phenomenon was remarkable in the hollow fiber membrane at the center of the cylindrical module, and was more remarkable in the large-sized one.
Further, even when the hollow fiber membrane module in which the hollow fiber membranes are fixed and integrated in this manner is regularly subjected to membrane surface cleaning or backwashing, it is not easy to recover the function of the module once fixed and integrated. A decrease in cleaning efficiency was seen.

As a solution to this problem, instead of a concentrating type (cylindrical type) hollow fiber membrane module, the hollow fiber membranes are arranged in a sheet form, and one end portion or both end portions of the hollow fiber membrane is one or A hollow fiber membrane module in which fixing members are fixed in two different housings while maintaining their respective open states, and the shape of a cross section of the fixing member perpendicular to the hollow fiber membranes is an elongated rectangular shape. Module is JP-A-5
It is proposed in Japanese Patent Laid-Open No. 220356.

In such a sheet-shaped flat hollow fiber membrane module, it becomes possible to evenly arrange the hollow fiber membranes in the inner and outer layers with a space between layers, and the surface of the hollow fiber membranes is washed during the cleaning of the membrane surface. It is a module suitable for filtering highly polluted water because it makes it extremely easy to wash it evenly, and can prevent the deterioration of filtration efficiency as it has been so far.

In using such a module,
When treating a large amount of water, it is necessary to increase the membrane area, but in order to increase the membrane area with one module, it is difficult to handle, and scrubbing cleaning is not performed efficiently on the entire module. However, there is a problem that it becomes larger than necessary, and it is not possible to increase the film area indefinitely with one module.

In particular, when a plurality of hollow fiber membrane knitted fabrics are laminated, the hollow fibers may be fixedly integrated with each other due to adhesion and accumulation of suspended matter, resulting in a reduction in effective membrane area and a decrease in scrubbing cleaning efficiency. is there. Further, even when a plurality of modules are mounted in parallel in the processing tank in order to increase the membrane area, the work of arranging and fixing each module in an appropriate position is complicated, and further However, it is difficult to arrange the air scrubbing uniformly.

The present invention provides a hollow fiber membrane module which has a large membrane area in a compact module, is easy to install and remove, and is capable of efficiently performing scrubbing cleaning on the entire hollow fiber membrane in the module, and the hollow fiber membrane module. It is intended to provide a manufacturing method.

[0011]

The gist of the present invention is as follows. (1) A hollow fiber membrane module in which one end or both ends of a hollow fiber membrane are fixed by a fixing member in a housing while maintaining an open state, and which has two or more sets of hollow fiber membrane knitted fabrics,
A hollow fiber membrane module, characterized in that the respective hollow fiber membrane knitted fabrics are juxtaposed at a distance equal to or more than a certain interval, and a plurality of knitted fabrics are integrally fixed to a resin fixing portion at an end portion.

(2) In the hollow fiber membrane module according to (1), which has three or more sets of hollow fiber membrane knitted fabrics, the hollow fiber membrane knitted fabrics are spaced at equal intervals. Thread film module. (3) The hollow fiber membrane module according to the above (1), wherein the knitted fabrics of hollow fiber membranes are fixed one by one at a distance of a certain distance or more.

(4) The hollow fiber membrane module according to the above (1), characterized in that a part of the housing material is embedded in a fixing member for fixing the hollow fiber membrane. (5) The hollow fiber membrane module according to (1), wherein the air diffuser is fixed and integrated. (6) The method for producing a hollow fiber membrane module according to the above (4), which uses a hollow core.

The present invention will be described in detail below with reference to the drawings. FIG. 1 is an external view showing an example of the hollow fiber membrane module of the present invention, in which seven sheet-shaped hollow fiber membrane knitted fabrics are used and arranged in parallel at equal intervals, and a resin fixing portion at one end of the hollow fiber membrane is used. It is a perspective view of the module which integrated.

FIG. 2 is a perspective view of the module of FIG. 1 in which both ends of the hollow fiber membrane are fixed with resin and the fixing portions are integrated. FIG. 3 is a perspective view of the module of FIG. 2 in which the corresponding four corners of both water collecting portions are supported by support bars.

FIG. 4 is a side view showing an example of a cross section perpendicular to the arrangement direction of the hollow fiber membranes in an example of the hollow fiber membrane module of the present invention. 5 and 6 are schematic diagrams showing steps in the method for manufacturing a hollow fiber membrane module of the present invention.

1 is a sheet-shaped hollow fiber membrane knitted fabric, 2 is a housing for holding a water collecting portion and a hollow fiber resin fixing portion, 3 is a resin fixing portion, 4 is a water pipe, 5 is a filtrate outlet, and 6 is a supporting rod. , 7 is potting resin, 8 and 8'are hollow cores, and 9 is a water collecting part.

The hollow fiber membrane 1 can be made of various materials such as cellulose-based, polyolefin-based, polyvinyl alcohol-based, polysulfone-based, etc. In particular, materials having high strength and elongation such as polyethylene and polypropylene can be used. preferable. There are no particular restrictions on the pore diameter, porosity, film thickness, outer diameter, etc., as long as it can be used as a filtration membrane, but it is necessary to secure the membrane area per removal object or volume and the strength of the hollow fiber membrane. Considering the above, a preferable example is a pore size of 0.
01 to 1 μm, porosity 20 to 90%, film thickness 5 to 300 μ
m and an outer diameter of 20 to 2000 μm.

Further, in the case of removing bacteria, it is essential that the pore size is 0.2 μm or less, and in the case of removing organic substances and viruses, the molecular weight cutoff is limited to tens to hundreds of thousands. An outer filtration membrane may be used.

As the surface characteristics of the hollow fiber membrane, a so-called permanent hydrophilization membrane having hydrophilic groups on the surface is desirable. As a method for producing the permanently hydrophilic membrane, known methods such as a method for producing a hollow fiber membrane with a hydrophilic polymer such as polyvinyl alcohol or a method for hydrophilizing the surface of a hydrophobic polymer membrane can be used.

For example, when a hydrophilic polymer is applied to the surface of the membrane to make the hydrophobic hollow fiber membrane hydrophilic, examples of the hydrophilic polymer include:
Examples thereof include saponified ethylene-vinyl acetate copolymers and polyvinylpyrrolidone. An example of hydrophilization of the membrane surface by another method is a membrane surface polymerization method of a hydrophilic monomer, and examples of this monomer include diacetone acrylamide.

As another method, a method of blending a hydrophobic polymer (for example, polyolefin) with a hydrophilic polymer to form a film by spinning can be cited. Examples of the hydrophilic polymer to be used are those mentioned above. Can be mentioned. When the surface is a hydrophobic hollow fiber membrane, hydrophobic interaction works between the organic matter in the water to be treated and the surface of the hollow fiber membrane to cause adsorption of organic matter on the membrane surface, which leads to blockage of the membrane surface and filtration. The life is shortened.

In addition, clogging caused by adsorption is generally difficult to recover the filtration performance by cleaning the membrane surface. By using the permanent hydrophilization membrane, the hydrophobic interaction between the organic matter and the hollow fiber membrane surface can be reduced, and the adsorption of the organic matter can be suppressed. Further, when scrubbing cleaning during use, a hydrophobic film may be dried and hydrophobized by the bubbling air, which may cause a decrease in flux. Never.

In the hollow fiber membrane module of the present invention, a sheet-shaped hollow fiber membrane knitted fabric is used. It is desirable that the intervals between the hollow fiber membrane knitted fabrics in the module be equal intervals in consideration of applying air bubbling evenly to the entire membrane surface during scrubbing cleaning. The distance can be selected as desired, but the distance between sheets is selected in consideration of the efficiency of scrubbing cleaning in air bubbling, adhesion prevention of adjacent hollow fiber membrane knitted fabric, and membrane area per module. .

A range of 5 to 100 mm is suitable. Furthermore, by fixing the hollow fiber membrane knitted fabrics one by one at a predetermined interval, it becomes possible to further prevent the hollow fiber membranes from being fixedly integrated with each other.

The housing 2 functions as a member for supporting the entire hollow fiber membrane module, and collects the filtrate obtained from the end faces of each hollow fiber membrane. Any material may be used as long as it has mechanical strength and durability, and examples thereof include hard polyvinyl chloride resin, polycarbonate, polysulfone, polypropylene, acrylic resin, ABS resin, and modified PPE resin. If incineration is required after use,
It is preferable to use a hydrocarbon resin that can be completely burned without producing a toxic gas by burning.

The resin fixing portion 3 is filled and fixed in the opening portion of the housing 2 to fix each end portion of a large number of hollow fiber membranes while keeping the open state, and to make this hollow fiber membrane function as a filtration membrane. In addition, it functions as a member that liquid-tightly separates the water to be treated and the treated water. The resin fixing portion 3 is usually formed by curing a liquid resin such as epoxy resin, unsaturated polyester resin, polyurethane or the like.

The water conduit 4 is a pipe through which the filtrate flows,
Connect to the filtrate outlet 5. The material is based on the housing 2. The support rod 6 supports and fixes two structural members (housings) facing each other in FIG. By fixing with a supporting means such as a supporting rod, there is an advantage that handling becomes easy. In addition, an embodiment in which a water conduit is used instead of the support rod to fix the distance between the two structural members is also possible. As such a supporting means, the following various modes can be considered in addition to the supporting rod shown in FIG.

A method of fixing the distance between the two structural members by using a wire netting or the like instead of the supporting rod can also be mentioned. In this embodiment, the hollow fiber membrane 1 held between the housings 2
Wire meshes may be arranged on all four sides of the hollow fiber membrane 1
The wire net may be arranged only below or above the wire mesh. In addition to the advantage of easy handling by adopting such a configuration, it also has a protective effect to prevent damage to the hollow fiber membranes and a spacer function to prevent the hollow fiber membranes from sticking to each other when the modules are stacked and used. can do. The same effect can be obtained by using a perforated plate instead of using a wire net.

Further, the support bar 6 can be expanded and contracted, and a module which can change the distance between the housings may be used. By increasing the relaxation of the hollow fiber membrane at the time of cleaning the membrane surface, the vibration of the hollow fiber at the time of bubbling can be enhanced, and the cleaning can be performed more effectively. The relaxed state of the hollow fiber membrane is preferably such that the hollow fiber membrane has a tension such that the effect of dispersing the hollow fiber membrane in a sheet form is sufficiently exerted even in the central portion of the module. If the relaxation is too large, the hollow fiber membrane becomes free in the center even if both ends are fixed, and the fixing effect is halved.

The length of the support rod or the support frame between the housings may be such that the hollow fiber membrane is not excessively strained, and it is usually used as long as possible within that range. However, in the case where the module itself is vibrated for cleaning the membrane surface, it may be desirable to reduce the distance between the fixing members to loosen it, and it can be appropriately selected as necessary.

When the hollow fiber membrane module of the present invention is used, a so-called pressure filtration method, in which the module is placed in a closed container and the water to be treated is pressed to permeate the hollow fiber membrane, can be used. It is preferable that the hollow fiber membrane module is arranged in a tank or a precipitation tank and used in a suction filtration method in which the side for collecting the treated water that has permeated the hollow fiber membrane is sucked.

In particular, by adopting a so-called intermittent suction operation method in which temporary suction is periodically stopped, it is possible to efficiently prevent film surface deposits from entering the inside of the film surface,
It is possible to reduce the frequency of function recovery processing of the hollow fiber membrane module. Since the optimum range of the intermittent intervals of intermittent suction differs depending on the pollution degree of the water to be treated, a clear range cannot be specified, but as an example when targeting activated sludge of about MLSS 5000 ppm, suction time 1 to Desirable examples include 30 minutes and a stop time of 2 seconds to 15 minutes.

Further, by adopting the suction filtration method, it becomes easy to circulate the water to be treated in the tank at the time of filtration or to wash the membrane surface by performing air bubbling. In particular, the cleaning method using air bubbling exerts a further cleaning effect by combining it with the intermittent suction operation method that can efficiently prevent film surface deposits from entering the film surface, as shown above. To do.

It is preferable that the flow of water to be treated in the suction filtration method is made to flow substantially perpendicularly to the direction in which the hollow fiber membranes are arranged so as to enhance the cleaning effect on the membrane surface of the hollow fiber membranes. As one of preferred uses of the hollow fiber membrane module of the present invention, particularly a module in which only one end of the hollow fiber membrane is fixed, a method of arranging this module in a rotating body and carrying out filtration while rotating the module is Can be mentioned.

As a method of attaching the module to the rotating body, the module housing is arranged so as to extend radially in the horizontal direction with the rotating body as the center, and the hollow fiber membranes are hung downward from the respective housings or the vertical direction. One example is a mode in which the hollow fiber membranes extend horizontally in a horizontal direction from a plurality of modules around a rotating body arranged in the direction.

As a method for recovering the function of the hollow fiber membrane module of the present invention, a backwashing method can be simply carried out as in the case of a normal module, but the membrane surface is physically washed using a sponge ball or the like. The method or the method using ultrasonic waves can be efficiently performed due to the physical form of the module.

In filtering highly polluted water, a large amount of ss
And organic matter is deposited. For this reason, it is necessary to clean the film surface by using water flow, air, vibration, ultrasonic waves or the like to remove the deposits. When the washing is not carried out, the organic substances deposited on the membrane surface cause the clogging of the membrane, leading to a reduction in filtration life.

Specific cleaning methods include so-called cross-flow filtration in which a water flow is made parallel to the membrane surface, a method of causing a water flow in a membrane module dipping tank with a pump or a motor, a bubbling method using an upward flow of air, a module. Examples thereof include a method of vibrating itself and a method of vibrating the liquid to be treated with ultrasonic waves. These washings may be performed continuously or intermittently depending on the degree of progress of the membrane surface blockage.

When operating while scrubbing cleaning by air bubbling, an air diffuser for bubbling is required. The positional relationship between the air diffusing tube and the module is important for proper air bubbling, but fixing the module and the air diffusing tube separately is a cumbersome task, and the module moves during operation. In that case, there is a problem that proper scrubbing cleaning cannot be performed during operation. As a measure against this, by fixing and integrating an air diffuser to the module of the present invention, it becomes easy to mount it on a can body or a treatment layer, and appropriate scrubbing cleaning can be continued during operation.

The air diffuser may be arranged in any manner as long as appropriate air bubbling can be performed on the hollow fiber membrane. Also, by attaching an air diffuser, it can be used as a support rod or a support frame. The hollow fiber membrane module of the present invention is particularly suitable for filtration of highly polluted water, and specific fields of application include filtration of river water, industrial tap water filtration, solid-liquid separation of wastewater, wastewater treatment (for example, Treatment in a combined septic tank) and the like.

The method for manufacturing the hollow fiber membrane module of the present invention is not particularly limited, but the following method can be mentioned. First, a knitted fabric having a hollow fiber membrane as a weft and a normal yarn as a warp (a woven fabric in the case of one hollow fiber rather than a combination of a plurality of hollow fibers) is prepared. As the type of the normal yarn used for the warp, all those used for the normal warp of a knitted fabric or a woven fabric can be used.

In order not to damage the hollow fiber membrane during the production or handling of the knit, the warp is preferably not hard, and multifilament, spun yarn or processed yarn is preferably used. There is no particular restriction on the material, polyester, nylon,
All commonly used ones such as vinylon can be used. The method for producing the above hollow fiber membrane knitted fabric is described in, for example, JP-A-62-57965 and JP-A-1-26662.
No. 58 is disclosed.

A plurality of hollow fiber membrane knitted fabrics (groups) are arranged in parallel at a predetermined equal interval, and one end or both ends of the hollow fiber membrane are resin-fixed while maintaining the open state. At this time, each of the hollow fiber membrane knitted fabrics may be one or a plurality of knitted fabrics laminated or folded to form one set.

The resin fixing portion of the hollow fiber membrane is fitted into the opening of the housing and fixed by adhesion. The shape of the resin fixing portion and the shape of the housing opening are the same. Since the filtrate is collected in the housing and guided to the water conduit, the space formed between the resin fixed end surface of the hollow fiber membrane and the inner surface of the housing needs a space through which the filtrate can flow without resistance.

The module thus manufactured has problems that the resin-fixed portion has a low pressure resistance, and that it requires a long time during manufacturing. Therefore, the module having a structure in which the cross section of the housing parallel to the hollow fiber membrane is as shown in FIG. The following method is preferable for manufacturing this module.

The housing in this manufacturing method has a sectional shape like the housing 2 of FIG. 4, and has a sufficient space (before being filled with resin) inside. 7 hollow fiber membrane knitted fabrics
When using one sheet, the housing has seven slits, and this surface is the upper side when fixing the resin.

The width of the slit is 5 to 20 mm, and the distance between the slits is 5 to 80 mm, and an arbitrary interval can be selected, but the efficiency of scrubbing cleaning in air bubbling and the like, and the prevention of adhesion of adjacent hollow fiber sheets, This distance can be selected in consideration of the membrane area per module and the like. The length of the slit is adjusted to the length in the direction perpendicular to the yarn length direction of one or a set of hollow fiber membrane knitted fabrics.
Further, there are edges on four sides of the surface of the housing having the slits. The edge height is 5-40 from the surface with the slit.
It can be selected between mm.

The hollow core 8 is inserted from the side surface of this housing as shown in FIG. In the hollow core of FIG. 5, 8 is a view seen from directly above, and 8'is a side view thereof. The hollow core is made of a thin resin on the outside and hollow inside.
Further, the recessed portion of the hollow core and the slit of the housing correspond to each other, and further, in order to provide a distance from the inner surface of the housing, there are projections on the two surfaces facing each other and the bottom surface. The material of the hollow core is not particularly limited, but materials such as polyethylene and polypropylene that are easy to mold and have a low elution property can be mentioned.

The slit of the housing and the concave portion of the hollow core are positioned so as to correspond to each other, and the surface on the side where the hollow core is inserted is closed.
Prevent the resin from leaking. Here, the surfaces A and B, which are the side surfaces of the housing 2 in FIG. 5, are brought into close contact with the hollow core so that the resin does not flow into the surfaces A and B.

As shown in FIG. 6, the hollow fiber membrane knitted fabric is inserted through the slit, and the folded back portion of the hollow fiber membrane knitted fabric (the folded portion of the hollow fiber membrane) is brought into contact with the bottom of the concave portion of the hollow core. At this time, by temporarily fixing the tip end of the hollow fiber membrane knitted fabric and the hollow core with an adhesive or the like, the hollow fiber membrane does not lift when the resin is poured, and the subsequent work is facilitated.

The potting resin is poured and filled in the housing in the state as shown in FIG. 6, that is, in the gap between the hollow core and the inner surface of the housing. The resin is poured not only on the upper surface of the slit but also on the entire edge of the housing to be cured.

The above-described method is a method in which the hollow fiber membrane knitted fabric is inserted into the housing and the hollow core in advance and then the resin is poured. However, the resin is first poured and filled, and then the resin is cured. The hollow fiber membrane knitted fabric may be inserted into the housing through the slit.

After the resin has hardened, the side surfaces of the housing, which are the surfaces A and B in FIG. 5, are removed, and a cutter for cutting from either surface is introduced. Only the concave part of the hollow core (the convex part when viewed from the inside of the hollow core) is cut with a cutter while the hollow core is adhered, and the opening of the hollow fiber membrane is formed on the cut surface Let Further, the space formed at the same time plays a role of a water collecting portion for collecting the filtrate obtained from each hollow fiber membrane. The cross-sectional view after cutting is as shown in FIG.

Again, the side A and the side B of the side surface of the housing are closed. At this time, water conduits are attached to both A side and B side or one side. The module thus manufactured has improved pressure resistance because the wall surface of the water collecting portion is covered with resin and the housing material is embedded inside the resin of the hollow fiber membrane fixing portion. Also, the potting process and the mounting process to the housing can be performed at the same time, which shortens the manufacturing time.

[0056]

EXAMPLES The present invention will be specifically described with reference to examples. Example 1 A hollow fiber membrane module as shown in FIG. 2 was produced. The hollow fiber membrane 1 is a porous hollow fiber membrane made of polyethylene, and the membrane surface of which is coated with a saponified product of an ethylene-vinyl acetate copolymer was knitted into a sheet to form a knitted fabric. As the hollow fiber membrane knitted fabric, seven pieces having a length of 790 mm in the yarn length direction and a length of 500 mm in the arrangement direction of the hollow fiber membranes were used.

By the manufacturing method of the present invention using the hollow core, both ends of the hollow fiber membrane were resin-fixed while keeping the open state, and the hollow fiber membrane knitted fabric was modularized by keeping a distance for each piece. The space between the hollow fiber membrane knitted fabrics was 20 mm. As the material of the housing, one made of polyvinyl chloride was used.
This module was immersed in 200 ppm of yeast suspension water, and filtered by suction with a pump from the secondary side of the module, that is, from the water conduit. LV = 0.01 m / h, intermittent interval 5
The operation was carried out in an operation cycle of minute suction for 5 minutes, and scrubbing was continuously performed with 50 Nl / min of air during the operation (while the operation was stopped). The results are shown in Table 1.

Comparative Example 1 A hollow fiber membrane knitted fabric similar to that used in Example 1 was used, in which the length of the hollow fiber membrane in the yarn length direction was 790 mm (same as in Example 1), and A flat hollow fiber membrane module was produced by using one sheet having a length of 1500 mm and fixing the resin at both ends of the hollow fiber membrane while keeping the open state.
Using this module, filtration was performed under exactly the same conditions as in Example 1. The results are shown in Table 1.

Comparative Example 2 The same hollow fiber membrane knitted fabric used in Example 1 (the lengths of the hollow fiber membranes in the yarn length direction and the arrangement direction are also the same), and 7 hollow fiber membrane knitted fabrics at intervals. Was laminated without opening, and both ends of each hollow fiber membrane were fixed with a resin while maintaining the open state to prepare a flat hollow fiber membrane module. Using this module, filtration was performed under exactly the same conditions as in Example 1.
The results are shown in Table 1.

[0060]

[Table 1]

In Comparative Example 1, only one hollow fiber membrane knitted fabric was used, but since the length of the hollow fiber membranes in the arrangement direction was large, air bubbling was difficult to occur on the entire knitted fabric, and scrubbing cleaning was performed on the entire module. Since it was difficult to carry out evenly, the differential pressure increased. In order to improve the cleaning efficiency, it is necessary to increase the amount of bubbling air, which causes a problem of increasing energy cost during operation. In addition, the width of the module becomes large and it is difficult to handle.

In Comparative Example 2, although the module is compact, since there is no space between the laminated knitted fabrics, the hollow fiber membranes are fixedly integrated with each other due to adherence and deposition of suspended matter, resulting in an increase in effective membrane area. An increase in differential pressure occurred due to a significant decrease.

On the other hand, in the module of the present invention (Example 1), uniform scrubbing cleaning was efficiently performed on the entire hollow fiber membrane in the module, and the operation could be stably continued at a low differential pressure. Further, despite having the same membrane area as the module of the above-mentioned comparative example, the volume occupied in the processing tank was small, and the mounting / demounting could be easily performed.

[0064]

EFFECTS OF THE INVENTION The hollow fiber membrane module of the present invention has a compact structure with a large membrane area, and more hollow fiber membranes come into direct contact with the water to be treated, and the hollow fiber membranes are fixed to each other. It is possible to prevent unification and keep high filtration efficiency for a long period of time, especially in filtration of highly polluted water. Further, it can be easily attached to and detached from the can body or the treatment tank, and is easy to handle. By fixing and integrating the air diffuser with the module, good scrubbing cleaning can be stably performed during operation. Further, the method for producing a hollow fiber membrane module of the present invention can shorten the production time, and the hollow fiber membrane module produced by this method has excellent pressure resistance.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a hollow fiber membrane module of the present invention.

FIG. 2 is a perspective view showing an example of a hollow fiber membrane module of the present invention.

FIG. 3 is a perspective view showing an embodiment of the hollow fiber membrane module of the present invention.

FIG. 4 is a cross-sectional view of an example of the hollow fiber membrane module of the present invention.

FIG. 5 is a schematic view of one step in the method for manufacturing a hollow fiber membrane module of the present invention.

FIG. 6 is a schematic view of one step in the method for manufacturing a hollow fiber membrane module of the present invention.

[Explanation of reference numerals] 1 sheet-like hollow fiber membrane knitted fabric 2 housing 3 resin fixing part 4 water conduit 5 filtrate outlet 6 support rod 7 potting resin 8, 8'hollow core

Front Page Continuation (72) Inventor Ikuo Kinoshita 4-60 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (6)

[Claims] 1. A hollow fiber membrane module in which one end or both ends of a hollow fiber membrane are fixed by a fixing member inside a housing while maintaining an open state, and which has two or more sets of hollow fiber membrane knitted fabrics. The hollow fiber membrane module is characterized in that the respective hollow fiber membrane knitted fabrics are juxtaposed at a distance equal to or more than a certain distance, and a plurality of knitted fabrics are integrally fixed to the resin fixing portion at the end. 2. The hollow fiber membrane module according to claim 1, which has three or more sets of hollow fiber membrane knitted fabrics, wherein the hollow fiber membrane knitted fabrics are spaced at equal intervals. module. 3. The hollow fiber membrane module according to claim 1, wherein the knitted fabrics of hollow fiber membranes are fixed one by one at a distance of a certain distance or more. 4. The hollow fiber membrane module according to claim 1, wherein a part of the housing material is embedded in a fixing member for fixing the hollow fiber membrane. 5. The hollow fiber membrane module according to claim 1, wherein the air diffuser is fixed and integrated. 6. The method for producing a hollow fiber membrane module according to claim 4, wherein a hollow core is used.