JPH0747238A - Hollow yarn membrane module and supporting method therefor - Google Patents

Abstract

PURPOSE:To perform good treatment by hardly generating the mutual interlocking and integration of hollow yarn membranes in a module even when the module is used for the filtration of highly polluted water by forming a hollow yarn membrane part from knitted fabrics using hollow yarn membranes as weft yarns and interposing a spacer between the knitted fabrics. CONSTITUTION:Hollow yarn membranes 3 are used as weft yarns to be formed into a knitted fabric and one knitted fabric or a laminate consisting of the knitted fabrics is received in the almost rectangular elongated opening part of a housing in a state converged into a U-shape. At this time, the respective end parts of the U-shaped hollow yarn membranes 3 are converged by a fixing member 2 to be fixed to the opening part of the housing 1 so as to hold the opening state of the housing. When a plurality of the knitted fabrics of the hollow yarn membranes 3 are used per one module, a spacer 4 is used in order to suppress the mutual contact of the knitted fabrics. Therefore, a large number of the hollow yarn membranes 3 can come into direct contact with water to be treated by the spacer 4.

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 (particularly organic matter pollutant). Specifically, solid-liquid separation in sewage treatment, industrial wastewater treatment (solid-liquid separation), river water filtration, industrial tap water filtration, pool water filtration, water filtration in the food industry and product clarification,
Filtration of liquor, beer, wine, etc. (particularly raw products), bacterial cell separation from fermenters in pharmaceuticals, foods, etc., filtration of water and dissolved dyes in the dyeing industry, seawater filtration, pure water production process in RO membranes, and Examples include pretreatment filtration in seawater desalination, pretreatment filtration in a process using an ion exchange membrane, and pretreatment filtration in a pure water production process using an ion exchange resin.

[0002]

2. Description of the Related Art Conventionally, hollow fiber membrane modules have been widely used in the field of so-called microfiltration such as aseptic water, drinking water, high-purity water production and air purification, but in recent years, in sewage treatment plants. Secondary treatment, tertiary treatment and solid-liquid separation in septic tanks, solid-liquid separation of ss (floating suspended solids) in industrial wastewater,
Various types of studies have been conducted for use in highly polluted water treatment applications such as direct filtration of river water in water purification plants, filtration of industrial tap water, and filtration of pool water.

However, the hollow fiber membrane module used in these fields is also a cylindrical type in which the hollow fiber membranes are arranged in a circular shape or concentric circles which have been used in the field of conventional microfiltration. Most of them were. 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 ≧ 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. In particular, this phenomenon was remarkable in the hollow fiber membrane in the central portion of the cylindrical module, and was more remarkable in the larger size.

The present inventors have previously proposed a hollow fiber membrane module molded in a rectangular shape (FIGS. 5 and 6) for the purpose of eliminating these disadvantages (Japanese Patent Application No. 4-58344).
Japanese Patent Application No. 4-161322, Japanese Patent Application No. 4-16132
No. 3). An example of the manufacturing method is to prepare a hollow fiber membrane knitted fabric, stack the fabrics, and fix them with resin.

These modules are very effective in filtering highly polluted water. However, when the number of hollow fiber membranes or the number of hollow fiber membrane knitted fabrics that can be accommodated in one module is increased, or when a plurality of modules are used and the intervals between the modules are fixed and supported, the hollow fiber membrane knitting is performed. Accumulation of ss was observed between the fabrics and between the modules, and the filtration efficiency was slightly reduced.

In addition, when the modules are supported and fixed by widening the intervals, particularly in the case of parallel support as shown in FIG. 7, when the cleaning is performed by air bubbling, the bubbles pass through the modules and the cleaning efficiency is lowered. Seen.

The object of the present invention is to prevent the hollow fiber membranes in a module from being fixedly integrated with each other even when used for filtering highly polluted water, and even when a plurality of modules are fixed with a narrow interval. Another object of the present invention is to provide a module or a module fixing method in which air bubbles are not adhered and the loss of air bubbles during cleaning is small even if the interval is fixed wide.

[0009]

That is, the gist of the present invention is as follows.

(1) In a hollow fiber membrane module in which the end portions of the hollow fiber membrane are held in an open state and fixed in a rectangular shape by a fixing member, the hollow fiber membrane portion has a plurality of hollow fiber membranes as weft yarns. A hollow fiber membrane module, characterized in that there is a spacer formed of knitted fabric and maintaining a gap between the knitted fabrics.

(2) In a hollow fiber membrane module in which the end portions of the hollow fiber membrane are fixed in a rectangular shape by a fixing member while keeping the ends open, when a plurality of modules are stacked or arranged in parallel, A method for supporting a hollow fiber membrane module, characterized in that a spacer is present between them.

During filtration of highly polluted water, a large amount of ss and organic substances are deposited on the film surface. In order to remove the deposit, it is necessary to clean the film surface with a stream of water, air, vibration, ultrasonic waves, or the like. If not washed, organic substances and the like deposited on the membrane surface may cause 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 to flow parallel to the membrane surface, a method of causing a water flow in the dipping layer of the membrane module with a pump or a motor, a bubbling method utilizing an upward flow of air, and 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 carried out continuously or intermittently depending on the progress of the film surface blockage.

In the above cleaning methods, cleaning is performed by physical action. Therefore, when the hollow fiber membranes are excessively fixed and integrated with each other, the cleaning efficiency is extremely reduced. In particular, when the hollow fiber membranes adhere to each other in the shape of a single rod as shown in FIG. 8, the cleaning is not easy.

The hollow fiber membrane module of the present invention will be described below. FIG. 1 is a perspective view showing an example of the hollow fiber membrane module of the present invention, and FIG. 2 is a sectional view thereof. The hollow fiber membrane module of the present invention basically comprises a housing 1, a fixing member 2, a hollow fiber membrane 3 and a spacer 4.

The housing 1 functions as a member for maintaining the whole hollow fiber membrane module and has an elongated rectangular opening. Any material may be used as long as it has mechanical strength and durability, and examples thereof include polycarbonate, polysulfone, polypropylene, acrylic resin, ABS resin, and modified PPE resin. When incineration is required after use, it is preferable to use a hydrocarbon resin that can be completely burned without producing harmful gas by burning.

The opening of the housing 1 must be such that the fixing member, which is filled and fixed together with the hollow fiber membrane, has a cross section perpendicular to the hollow fiber membrane that is elongated and substantially rectangular. The length of the short side of this rectangle is preferably 30 mm or less, and particularly preferably 15 mm or less.

In this way, the hollow fiber membrane is developed in the form of a flat sheet, so that the entire hollow fiber membrane is fixedly integrated into a single rod, and the effective membrane area of the hollow fiber membrane is rapidly increased. It can be prevented from falling.

Even if the hollow fiber membranes are adhered to each other, the adhered portion of the hollow fiber membranes is thin and the hollow fiber membranes are arranged in the form of a sheet. Can be recovered.

The length of the long side of the rectangle is not particularly limited, but if it is too short, the number of hollow fiber membranes that can be arranged in one hollow fiber membrane module decreases, which is not preferable.
On the other hand, if it is too long, the production becomes difficult, which is not preferable. Usually, the length of the long side is about 100 to 2000 mm.

The fixing member 2 is filled and fixed in the opening of the housing 1, and the end portions of the large number of U-shaped hollow fiber membranes 3 are converged and fixed while keeping the open state. In order to function as a filtration membrane, it functions as a member that liquid-tightly separates the water to be treated and the treated water. The fixing member 2 is usually formed by curing a liquid resin such as epoxy resin, unsaturated polyester resin, polyurethane or the like.

As the hollow fiber membrane 3, various types can be used, for example, various types of materials such as cellulose type, polyolefin type, polyvinyl alcohol type, PMMA type and polysulfone type can be used.

Considering the ease of processing into a knitted fabric, a material having a high strength and elongation such as polyethylene or polypropylene is preferable. The pore diameter, porosity, film thickness, outer diameter, etc. are not particularly limited as long as they can be used as a filtration membrane.

In order to store the hollow fiber membranes 3 in a U-shaped configuration in a long and narrow rectangular opening of the structural material 1, for example, one piece of knitted fabric using the hollow fiber membranes as a weft, Alternatively, it is preferable to use a laminate in which several knitted fabrics are laminated.

In the case of the conventional cylindrical module, there was no difficulty in accommodating the hollow fiber membranes which have been collected and converged in the cylindrical structural material.

On the other hand, it is difficult to store the hollow fiber membrane stripped in the elongated rectangular opening, but it can be easily stored if a knitted fabric is used. The layering of the knitted fabric here includes a knitted fabric that is folded and stacked to an appropriate length without being cut.

The number of laminated (folded) knitted fabrics varies depending on the thickness of the knitted fabric, that is, the thickness of the hollow fiber membrane and the number of yarns of the hollow fiber membrane when knitting the knitted fabric, but usually 5 sheets. It is preferable that the fixing member is configured so as to satisfy the limitation of the length of the short side of the rectangular section of the fixing member.

The spacer 4 functions as a member for suppressing contact between knitted fabrics when a plurality of hollow fiber knitted fabrics are used per module. Although a cylindrical pipe-shaped spacer is illustrated in FIG. 1, the shape of the spacer is not limited to this, and various shapes such as a mesh, a corrugated plate, a perforated plate, and a grooved plate as shown in FIG. Can be used.

Examples of the material of the spacer include polyvinyl chloride, polycarbonate, polysulfone, polyethylene, polypropylene, acrylic resin, ABS resin, modified PPE resin and other synthetic resins, metal, wood, fibers and the like.

The contact portion with the hollow fiber membrane must not scratch the hollow fiber membrane when rubbed against the hollow fiber membrane. If the shape has corners, chamfering, etc. Need to be applied. Considering the corrosion resistance and the ease of processing, it is desirable to use a synthetic resin.

Further, as shown in FIG. 4, even when a plurality of modules are used, a spacer is used for the purpose of preventing the hollow fiber membranes from adhering to each other and allowing the cleaning air to satisfactorily hit the membrane surface. Examples of the shape and material include the same range as shown above.

As described above, in using the hollow fiber membrane module of the present invention, a so-called pressure filtration method in which the module is placed in a closed container and the water to be treated is pressurized to permeate the hollow fiber membrane is also used. Although it can be adopted, it is desirable to use a suction filtration method in which a hollow fiber membrane module is provided in an activated sludge tank or a sedimentation tank and 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 film surface deposits from entering the internal pores.

In the suction filtration method, the water to be treated outside the module may be stopped, but it may be stirred or the water to be treated may be made substantially vertical to the direction in which the hollow fiber membranes are arranged. It is preferable to carry out the treatment by flowing the hollow fiber membrane to improve the cleaning efficiency of the membrane surface.

[0036]

EFFECTS OF THE INVENTION In the hollow fiber membrane module of the present invention, by effectively using the spacer, more hollow fiber membranes come into direct contact with the water to be treated, so that the accumulation of organic substances between the hollow fiber membranes is suppressed, It is possible to prevent the hollow fiber membranes from being fixedly integrated with each other, and it is possible to maintain a high filtration efficiency for a long time, particularly in the filtration of highly polluted water.

Further, it can be easily arranged in a filter tank or the like, and can be easily installed even when a plurality of modules are used.
Further, the filtering function recovery process such as 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.

2 is a cross-sectional view of the module of FIG.

FIG. 3 is a perspective view showing a shape example of a spacer.

FIG. 4 is a cross-sectional view showing an example of a method for supporting a hollow fiber membrane module using the spacer of the present invention.

FIG. 5 is a perspective view showing an embodiment of a hollow fiber membrane module molded into a rectangle.

FIG. 6 is a perspective view showing another mode of the hollow fiber membrane module molded into a rectangle.

FIG. 7 is a perspective view showing an example of a supported state of a hollow fiber membrane module molded into a rectangle.

FIG. 8 is a perspective view showing an example of a hollow fiber membrane module molded in a fixedly integrated rectangular shape.

[Explanation of symbols]

 1 Housing 2 Fixing Member 3 Hollow Fiber Membrane 4 Spacer 5 Outlet

Claims (2)

[Claims] 1. A hollow fiber membrane module in which an end of a hollow fiber membrane is fixed in a rectangular shape by a fixing member while keeping an end thereof open, and a plurality of knitted fabrics in which the hollow fiber membrane portion uses the hollow fiber membrane as a weft. A hollow fiber membrane module, characterized in that there is a spacer formed of the ground and maintaining a space between the knitted fabrics. 2. A hollow fiber membrane module in which a hollow fiber membrane is fixed in a rectangular shape with a fixing member while keeping an end portion of the hollow fiber membrane in an open state, and when a plurality of modules are stacked or used in parallel, the module and the module are used. A method for supporting a hollow fiber membrane module, characterized in that a spacer is present between the two.