JPH0724267A - Hollow fiber membrane module - Google Patents

Abstract

PURPOSE:To prevent hollow fiber membranes in a module from sticking into one body even when the module is used to filter highly polluted water by arranging webs of hollow fiber membranes or hollow fiber membrane bundles in such a manner that the longitudinal direction of hollow fiber membrane differs from one another and the end of each hollow fiber membrane bundle has one common part to collect water. CONSTITUTION:This hollow fiber membrane module consists of two or more webs or bundles of hollow fiber membranes 1 with each one end fixed as an aperture state maintained in a housing. The longitudinal direction of each hollow fiber membrane web or bundle is different from one another and the end of every bundle has one common part 2 to collect water. Thereby, even when the module is used to filter highly polluted water, hollow fiber membranes are hardly stuck into one body. Moreover, filtering function of the obtd. hollow fiber membrane module which is decreased by use can easily and efficiently be recovered.

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 highly polluted liquid.

[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 been highly polluted such as secondary and tertiary treatment in sewage treatment plants and solid-liquid separation in septic tanks. Various types of studies have been conducted for use in water treatment applications.

Since the hollow fiber membrane module used for such an application has a large clogging of the hollow fiber membrane during the filtration treatment, after the filtration treatment for a certain period of time, air is sent to vibrate the hollow fiber membrane and the membrane surface is cleaned. The membrane surface is repeatedly washed, for example, by passing treated water in the opposite direction to the filtration treatment.

Hollow fiber membrane modules used in these fields are mostly of the cylindrical type in which hollow fiber membranes are concentrically arranged in a circular shape or concentric circles which have been used in the field of conventional microfiltration. It was. Further, even if improvements are made, many of them merely change the filling rate or filling form of the hollow fiber membrane.

[0005]

Highly polluted water (for example, ss ≧ 5) is obtained by using such a conventional hollow fiber membrane module.
When the filtration treatment (0 ppm, TOC ≧ 100 ppm) is performed, the hollow fiber membranes are fixed (adhered) and integrated with each other through the deposits such as organic substances attached to the surface of the hollow fiber membranes during use. As a result, the effective membrane area of the hollow fiber membrane in the module was reduced, and the filtration flow rate was rapidly reduced.

Even when the hollow fiber membrane module in which the hollow fiber membranes are fixed and integrated as described above is regularly subjected to membrane surface cleaning or backwashing, it is not easy to recover the function of the module once fixed and integrated. However, the cleaning efficiency decreased.

As a solution to this problem, a hollow fiber membrane module is replaced with a concentrating hollow fiber membrane module, and the hollow fiber membranes are arranged in a sheet form.
A hollow fiber membrane module in which one end or both ends of the hollow fiber membrane are fixed by one or two different fixing members in housings while maintaining their respective open states,
There has been proposed a hollow fiber membrane module in which the shape of a cross section of the fixing member perpendicular to the hollow fiber membrane is elongated and substantially rectangular.

In such a sheet-shaped flat hollow fiber membrane module, the hollow fiber membranes can be evenly arranged in the inner and outer layers with a space between layers, and the surface of the hollow fiber membranes can be cleaned during membrane surface cleaning. 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 the conventional hollow fiber membrane module and the above-mentioned modules, in order to increase the membrane area of the filtration module, it is possible to increase the number of hollow fiber membranes per module or increase the length of the hollow fiber membranes. It is being appreciated.

Regarding increasing the length of the hollow fiber membrane, as the length of the hollow fiber membrane increases to some extent, the flow rate of the module also increases in accordance with the membrane area.
If the yarn length becomes long, the resistance inside the hollow fiber membrane tube becomes large, and it becomes difficult to use the membrane surface for filtration at a location where the distance from the focusing end portion is long, and the utilization efficiency of the entire membrane decreases.

Also, a hollow fiber membrane knitted fabric having an appropriate yarn length or a hollow fiber membrane processed into a sheet form is laminated on several sets of potted modules, that is, all the hollow fiber membranes have the same longitudinal direction. Then, in a hollow fiber membrane module in which a large number of sheet-shaped hollow fiber membrane aggregates are stacked, a phenomenon occurs in which the hollow fiber membranes are converged, fixed and integrated, and the membrane surface cannot be effectively used. Further, there is a problem that the efficiency of cleaning the film surface in air scrubbing is also reduced.

According to the present invention, even when it is used for filtering highly polluted water, the hollow fiber membrane in the module is hard to be fixed and integrated, and the recovery function of the filtering function deteriorated by the use can be easily and efficiently carried out. An object is to provide a thread film module.

[0013]

The gist of the present invention is as follows.

(1) In a hollow fiber membrane module in which two or more sets of hollow fiber membrane knitted fabrics or hollow fiber membrane bundles are fixed at one end while being kept open by a fixing member in the housing, A hollow fiber membrane module, characterized in that the longitudinal direction of the hollow fiber membranes in the fiber membrane knitted fabric or the hollow fiber membrane bundle is different, and that each hollow fiber membrane focusing end face shares one water collecting portion.

(2) Having two sets of sheet-shaped hollow fiber membrane knitted fabrics, the yarn length direction of the hollow fiber membranes in one hollow fiber membrane knitted fabric and the yarn length of the hollow fiber membranes in the other hollow fiber membrane knitted fabric. The hollow fiber membrane module according to (1), which has an angle of 180 ° between the directions.

(3) Having two sets of sheet-shaped hollow fiber membrane knitted fabrics, the length direction of the hollow fiber membranes in one hollow fiber membrane knitted fabric and the length direction of the hollow fiber membranes in the other hollow fiber membrane knitted fabric The angle α between the two is 10 ° ≦ α <180 °, the hollow fiber membrane module according to (1).

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows that six sets of sheet-shaped hollow fiber membrane knitted fabrics are used,
It is a perspective view of the module of this invention which fixed each hollow fiber membrane knitted fabric radially centering around a water collection pipe.

FIG. 2 shows that two sets of sheet-shaped hollow fiber membrane knitted fabrics are used, and the hollow fiber membrane knitted fabrics each have a yarn length direction of 180.
° Different modules.

FIG. 3 shows that two sets of sheet-shaped hollow fiber membrane knitted fabrics are used, and the hollow fiber membrane knitted fabrics have a length of 1
FIG. 11 is a perspective view of a module with an angle of 20 °.

FIG. 4 shows an example of a module arrangement when the four hollow fiber membrane modules shown in FIG. 3 are immersed in a tank, and the water in the tank is filtered by sucking with a pump from the secondary side of the module. is there.

1 is a hollow fiber membrane knitted into a sheet, 2
Is a water collecting tube, 3 is a bundled end of the hollow fiber membrane, 4 and 5 are restraining yarns at the end of the sheet, 6 is the hollow fiber membrane module shown in FIG.
Reference numeral 7 is a tank, 8 is a blower for generating air bubbling, and 9 is a suction pump.

The hollow fiber membrane 1 is made of, for example, cellulose type, polyolefin type, polyvinyl alcohol type, PMMA type,
Materials made of various materials such as polysulfone can be used, and materials having high strength and elongation such as polyethylene and polypropylene are particularly preferable.

If it can be used as a filtration membrane,
The pore diameter, porosity, film thickness, outer diameter, etc. are not particularly limited, but in view of securing a membrane area per removal object or volume and the strength of the hollow fiber membrane, a preferable example is a pore diameter of 0. 01
˜1 μm, porosity 20 to 90%, film thickness 5 to 300 μm,
The outer diameter may be in the range of 20 to 2000 μm.

When the purpose is to remove bacteria, it is essential that the pore size is 0.2 μm or less. When the purpose is to remove organic substances and viruses, the molecular weight cutoff is in the range of tens to hundreds of thousands. A filtration membrane may be used in some cases.

The surface characteristics of the hollow fiber membrane are ethylene-
A so-called permanent hydrophilization film having a hydrophilic group on the surface thereof while holding a polymer such as a saponified product of vinyl acetate copolymer is desirable. 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.

Further, it is generally difficult to recover the filtration performance by cleaning the membrane surface due to clogging caused by adsorption. 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.

The water collection pipe 2 functions as a member for supporting the entire hollow fiber membrane module and has an elongated, substantially rectangular opening. The opening of the water collecting pipe 2 has an elongated rectangular shape whose cross section perpendicular to the hollow fiber membrane of the fixing member (that is, the hollow fiber membrane collecting end 3) that is filled and fixed together with the hollow fiber membrane. Is.

The material may be any one having mechanical strength and durability, such as polycarbonate,
Polysulfone, polypropylene, acrylic resin, AB
Examples include S resin, modified PPO resin, polyvinyl chloride resin, and the like.

The hollow fiber membrane converging end portion 3 is formed by a member which is filled and fixed in the opening portion of the water collecting pipe, and which condenses and fixes each end portion of a large number of U-shaped hollow fiber membranes 1 while keeping the open state. In addition, the hollow fiber membrane also functions as a filtration membrane and is a member that liquid-tightly separates the liquid to be treated from the liquid to be treated. This member is
It is usually formed by curing liquid resin such as epoxy resin, unsaturated polyester resin, and polyurethane.

The constraining filaments 4 and 5 are sheets which are formed by fixing the hollow fiber membranes 1 forming the sheet-like knitting at the outermost end of the hollow fiber membrane module to each other.
Generally, it is used as a warp at the time of forming a sheet-shaped hollow fiber membrane, and the hollow fiber membranes 1 are continuously constrained in a chain knitting pattern. As the types of fibers constituting the constraining yarns 4 and 5, multifilament yarns and spun yarns made of synthetic fibers having water resistance such as polyester fibers are used.

In the drawing, the hollow fiber membrane knitted fabric is fixed before the module is fixed to the can body or the treatment tank,
Although the hollow fiber membrane is not pulled along the length direction of the fiber, the outer frame and support rods that fix the hollow fiber membrane during module molding are attached to the module to fix the length direction of the hollow fiber membrane in advance. It does not matter even if it is a module that does. Such a module is easier to attach to the can body or the processing tank.

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 sedimentation tank and used in a suction filtration method in which the side for collecting the treated water that has permeated the hollow fiber filtration membrane is sucked.

In particular, the suction is periodically stopped for a predetermined time,
By adopting the so-called intermittent suction operation method, it is possible to efficiently prevent the membrane surface deposits from entering the internal pores and reduce the frequency of function recovery treatment of the hollow fiber membrane module.

The flow of water to be treated in the suction filtration method is preferably made to flow almost perpendicularly to the longitudinal direction of the hollow fiber membrane so as to enhance the contact with the hollow fiber membrane and enhance the cleaning effect on the membrane surface. .

Further, as one of the preferable usage methods suitable for the shape of the hollow fiber membrane module of the present invention, there is a method of arranging this module in a rotating body and carrying out filtration while rotating the module.

As a method of attaching the module to the rotating body, for example, there is a mode in which the rotating body and the water collecting pipe are connected, and the module is arranged so as to rotate about the water collecting pipe as an axis. At this time, the water collecting pipe may be arranged in any direction such as a horizontal direction, a vertical direction, or a fixed angle.

As shown in FIG. 3, when two sets of sheet-like hollow fiber membrane knitted fabrics are used and an angle is maintained between the yarn length directions of the respective hollow fiber membrane knitted fabrics, the angle is from 10 °. 1
80 ° is selected.

As shown in FIG. 4, this module is fixed in a can body or a tank so that the water collecting portion faces upward, so that the potting portion is directed downward to the front end portion of the hollow fiber membrane knitted fabric. The slope is maintained, and the accumulation of suspended matter near the potting can be reduced.

This effect is enhanced as the inclination becomes steeper, that is, as the angle between the yarn length directions of the respective hollow fiber membrane knitted fabrics becomes smaller, but the respective hollow fiber membrane knitted fabrics come into contact during operation. Such an angle is not preferable. Further, it is desirable to select a necessary angle according to the size and shape of the can body or tank.

The hollow fiber membrane module of the present invention is particularly suitable for filtration of highly polluted water. Specific fields of application include filtration of river water, industrial water filtration, solid-liquid separation of sewage, and wastewater treatment ( For example, treatment in a combined septic tank) and the like.

[0041]

By making the length of the hollow fiber membrane to be used so that the influence of the resistance in the tube is reduced, the permeation flow velocity on the membrane surface is almost the same from the vicinity of the converging end to the tip of the hollow fiber membrane. Therefore, during filtration, all membrane surfaces in the module are effectively utilized.

Since a plurality of hollow fiber membrane knitting fabrics or hollow fiber membrane bundles are used, the membrane area is not reduced even though the yarn length is shortened, and each hollow fiber membrane knitting fabric is not used. Since the yarn length direction of the fabric or the hollow fiber membrane bundle is different,
Adhesion and integration due to convergence of hollow fiber membranes are reduced, effective use of the membrane surface is achieved, and even in membrane surface cleaning such as air scrubbing that vibrates the yarn, air is easily applied to the entire hollow fiber membranes and cleaning efficiency is improved. Also rises.

Further, two sets of hollow fiber membrane knitted fabrics were used, and potting was carried out so as to form an angle between the respective yarn length directions. The hollow fiber membrane knitted fabric is inclined from the potting portion toward the outermost end by fixing it in the can body or the tank so that the upper part is located above. Due to this inclination, it becomes difficult for turbidity to be deposited on the hollow fiber membrane near the potting area where the filtration efficiency is high, and the high filtration flow rate is maintained for a long time.

[0044]

EXAMPLES The present invention will be described with reference to examples. Example 1 A hollow fiber membrane module as shown in FIG. 1 was produced. The hollow fiber membrane 1 is a polyethylene-made porous hollow fiber membrane having a saponified product of an ethylene-vinyl acetate copolymer held on its surface,
This was knitted into a sheet to obtain a knitted woven fabric. As the binding yarn 4, a multifilament yarn of polyester fiber was used.

The hollow fiber membrane knitted fabric has a length of 200 in the yarn length direction.
mm, the length of the hollow fiber membrane in the direction of arrangement is 400 mm 1
One end of the hollow fiber membrane knitted fabric was fixed with a polyurethane resin using a single piece. In addition, each end of the hollow fiber membrane 1 was resin-fixed while maintaining the open state.

Six sets of hollow fiber membrane knitted fabrics, one end of which was fixed with a resin, were prepared in this manner, and these were fitted into a pipe made of polyvinyl chloride to form a module. The inner diameter of the pipe is 50 m
m, an outer diameter of 66 mm, and a length of 500 mm were used, and the hollow fiber membrane was preliminarily cut according to the dimensions of the resin fixing portion. This pipe corresponds to the water collection pipe 2.

The angles existing between the hollow fiber membrane knitted fabrics adjacent to each other in the longitudinal direction of the hollow fiber membrane were uniformly fixed at 60 °. In order to maintain this angle, a fixing member made of stainless steel was provided at the edge of each hollow fiber membrane knitted fabric, and the tip of the hollow fiber membrane knitted fabric was fixed to this to hold the angle. The fixing member was also connected to the water collecting pipe, and was provided so as to frame the hollow fiber membrane knitted fabric.

This module was immersed in 200 ppm of yeast suspension water, the water collection pipe and the inlet side of the pump were connected,
Filtration was performed by pumping from the secondary side of the module. As a result, the hollow fiber membranes do not adhere to each other and are integrated,
The entire membrane surface was effectively used and stable filtration was performed.

Example 2 A hollow fiber membrane module as shown in FIG. 3 was produced. Similar to the one manufactured in Example 1, two sets were prepared with one end fixed with a resin, and these two sets were fitted into a pipe made of polyvinyl chloride to form a module.

A pipe having an inner diameter of 30 mm, an outer diameter of 35 mm and a length of 500 mm was used, and a pipe having a slit formed in advance according to the dimensions of the resin fixing portion of the hollow fiber membrane was used.
This pipe corresponds to the water collection pipe 2.

The angle existing between the hollow fiber membrane longitudinal directions of the hollow fiber membrane knitted fabrics was set to 120 °. In order to maintain this angle, a fixing member made of stainless steel was provided on the edges of both hollow fiber membrane knitted fabrics, and the tip of the hollow fiber membrane knitted fabric was fixed to this to hold the angle. The fixing member is connected to the water collecting pipe so that the entire module is surrounded by a frame.

This module was immersed in 200 ppm of yeast suspension water, the water collection pipe and the inlet side of the pump were connected,
Filtration was performed by pumping from the secondary side of the module. The module was fixed in such a manner that the water collection tube was positioned at the top and the tip of each hollow fiber membrane knitted fabric (that is, the binding yarns 4 and 5 at the end of the sheet) was at the bottom.

During the filtration operation, the module surface was continuously scrubbed with air of 35 N1 / min from below the sheet surface to clean the membrane surface. As a result, the hollow fiber membranes are not fixedly integrated with each other, effective use of the entire membrane surface and improvement of the membrane surface cleaning efficiency are achieved, and when filtration is performed at a constant flow rate, long-term filtration with stable differential pressure is achieved. It was conducted.

The sheet-like hollow fiber membrane knitted fabric used in the hollow fiber membrane module in the examples of the present invention is produced by any method, for example, Japanese Patent Laid-Open No. 62-57965 and Japanese Patent Laid-Open No. 63-91673. It can be easily manufactured by using the method described in the publication.

[0055]

EFFECTS OF THE INVENTION In the hollow fiber membrane module of the present invention, since more hollow fiber membranes come into direct contact with the water to be treated, adhesion and integration between the hollow fiber membranes are prevented, and especially in the filtration of highly polluted aqueous water. It is possible to maintain high filtration efficiency for a long period of time. Further, since the hollow fiber membranes are dispersed and modularized, the filtering function recovery treatment by washing can be efficiently performed.

[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 diagram showing an example of a method of using the hollow fiber membrane module of the present invention.

[Explanation of symbols]

 1 Hollow Fiber Membrane 2 Water Collection Tube 3 Hollow Fiber Membrane Converging End 4 Restraint Thread at the Edge of Sheet 5 Restraint Thread at the Edge of Sheet 6 Hollow Fiber Membrane Module 7 Tank 8 Blower 9 Suction Pump

Claims (3)

[Claims] 1. A hollow fiber membrane module in which two or more sets of hollow fiber membrane knitted fabrics or hollow fiber membrane bundles are fixed at one end while being kept open by a fixing member in a housing. A hollow fiber membrane module, wherein the longitudinal direction of the hollow fiber membranes in the membrane knitted fabric or the hollow fiber membrane bundle is different, and each of the hollow fiber membrane focusing end faces shares one water collecting portion. 2. Having two sets of sheet-shaped hollow fiber membrane knitted fabrics,
The angle of 180 ° between the yarn length direction of the hollow fiber membrane in one hollow fiber membrane knitted fabric and the yarn length direction of the hollow fiber membrane in the other hollow fiber membrane knitted fabric. Hollow fiber membrane module. 3. Having two sets of sheet-like hollow fiber membrane knitted fabrics,
The angle α between the yarn length direction of the hollow fiber membrane in one hollow fiber membrane knitted fabric and the yarn length direction of the hollow fiber membrane in the other hollow fiber membrane knitted fabric is 10 ° ≦ α <180 ° The hollow fiber membrane module according to claim 1.