JPH11319507A - Hollow fiber membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow fiber membrane module whose hollow fiber membranes are prevented from damages due to deterioration of the membranes by installing a protective cylinder for covering the hollow fiber membrane bundle near the adhesive fixation part and preventing deposition of suspended solid in the protective cylinder. SOLUTION: In this hollow fiber membrane module, a bundle 2 of a large number of hollow fiber membranes having an adhesive fixed part 3 in at least one end is fixed in an upper part of a housing 1 and the circumference of the hollow fiber membrane bundle 2 in the fixed end is covered with a protective cylinder 4 extended from the adhesive fixed part 3 and an air jetting hole 6 for air scrubbing is formed in a lower part of the housing 1 and an air discharge port 7 is formed in the peripheral part of the adhesive fixed part 3 in the upper part of the housing. In such a hollow fiber membrane module, the cylindrical face of the protective cylinder 4 is made a closed face through which a fluid is impossible to pass in the region at least 10 mm from the adhesive fixed part 3 and an opening part 40 through which a fluid can freely pass is formed in a region of 10-60 mm from the adhesive fixed part 3.

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 for performing a liquid filtration operation while using air scrubbing, and more particularly, to a hollow fiber membrane module provided with a protective tube at a fixed end of a hollow fiber membrane bundle. The present invention relates to a hollow fiber membrane module capable of preventing the accumulation of suspended matter near the fixed end of a fiber membrane bundle.

[0002]

2. Description of the Related Art A hollow membrane module using a porous hollow fiber membrane has a large filter membrane area per unit volume, and thus has been widely used as a means for removing suspended substances in industrial water. Have been. As an embodiment of such a hollow membrane module, air is periodically introduced from an air injection port provided at a lower portion of the housing, and the hollow fiber membrane is vibrated by air scrubbing to remove deposits on the membrane surface. There is something.

However, in the hollow membrane module using air scrubbing in combination, the introduced air excessively fluctuates near the fixed portion of the hollow fiber membrane bundle, so that the fixed end portion of the hollow fiber membrane is damaged or introduced. The drawback of the hollow fiber membrane into the air outlet also caused problems such as blocking the discharge nozzle.

As a countermeasure against such a problem, there has been proposed a hollow membrane module in which the vicinity of a fixed end of a hollow fiber membrane bundle is covered with a cylindrical protective tube as shown in FIG. This hollow fiber membrane module is composed of a hollow membrane bundle 2 folded into a U shape.
Are fixed to the adhesive fixing portion 3, and the adhesive fixing portion 3
Is mounted on the upper inside of the housing 1. A protective tube 4 is fixed to the inner surface of the adhesive fixing portion 3 so as to extend downward. The protective tube 4 protects the periphery of the fixed end of the hollow fiber membrane bundle 2 so as to be covered.

A supply port 5 for a liquid to be treated such as industrial water is provided at a lower portion of the housing 1 and an air injection port 6 (nozzle) for introducing air for air scrubbing.
Are arranged in a ring shape. In the upper part of the housing 1, a discharge port 7 is provided in the vicinity of the adhesive fixing section 3 for both draining the liquid to be treated and discharging air. Also,
An outlet 8 for filtered water is provided outside the adhesive fixing portion 3 at the end of the housing 1.

In the above-mentioned hollow fiber membrane module, when air scrubbing operation is performed by injecting air from the air injection port 6, the hollow fiber membrane bundle 2 swings, but the fixed portion at the upper end is surrounded by the protective cylinder 4 and the degree of freedom is increased. Because of the limitation, excessive shaking does not reach the fixing portion with respect to the adhesive fixing portion 3, and it is possible to prevent breakage due to shearing force and the like. Further, it becomes difficult for the hollow fiber membrane to be drawn into the outlet 7.

However, when the protection cylinder 4 is provided as described above,
Even after air scrubbing, the adhesive fixing portion 3 of the hollow fiber membrane bundle 2
Since the movement in the vicinity is extremely restricted, suspended substances attached to the filtration membrane surface are gradually deposited easily, and the effective membrane area contributing to filtration is gradually reduced by the growth of the deposits. Go. In addition, even in a normal filtration operation, the hollow fiber membrane is deteriorated in a portion where the sediment has accumulated in the protection cylinder, and the hollow fiber membrane breaks.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a protective cylinder for covering a bundle of hollow fiber membranes near an adhesive fixing portion, to prevent suspended solids from accumulating in the protective cylinder, and to degrade the hollow fiber membrane. It is an object of the present invention to provide a hollow fiber membrane module which prevents damage due to the above.

[0009]

According to the hollow fiber membrane module of the present invention, an adhesive fixing portion to which at least one end of a large number of hollow fiber membrane bundles is fixed is fixed to an upper portion of a housing, and the periphery of the fixed end of the hollow fiber membrane bundle is fixed. In a hollow fiber membrane module covered with a protective cylinder extending from the adhesive fixing portion, an air injection port for air scrubbing is provided at the lower portion of the housing, and an air outlet is provided near the adhesive fixing portion at the upper portion of the housing. At least 10 m from the surface of the protective cylinder
m is a closed surface through which a fluid cannot flow, and an opening that can freely flow is provided in a range of 10 to 60 mm from the adhesive fixing portion.

As described above, in the present invention, although the protection cylinder for suppressing the vibration of the hollow fiber membrane during the air scrubbing is provided, the cylinder surface at least 10 mm from the adhesive fixing portion is formed as a closed surface through which fluid cannot flow. , 10 to 60 mm, a free-flowing opening is provided, so that an air pocket is formed in the protective tube in a region at least 10 mm from the adhesive fixing portion. In this air reservoir, suspended matter does not accumulate, so that the hollow fiber membrane does not deteriorate due to the deposit near the adhesive fixing portion, and the hollow fiber membrane does not break due to the deterioration.

[0011]

1A and 1B show an example of a hollow fiber membrane module according to the present invention. The basic structure of the hollow fiber membrane module is the same as the conventional one shown in FIG. 3. The hollow membrane bundle 2 has an intermediate portion bent in a U-shape and both end portions are fixed to the adhesive fixing portion 3. The adhesive fixing portion 3 to which the hollow fiber membrane bundle 2 is fixed is attached to the upper inside of the housing 1. A protective tube 4 is fixed to the inner surface of the adhesive fixing portion 3 so as to extend downward, and the inside of the fixed end portion of the hollow fiber membrane bundle 2 is protected inside.

In the lower portion of the housing 1, a supply port 5 for the liquid to be treated is provided, and an air injection port 6 (nozzle) for air scrubbing is provided. In the upper part of the housing 1, a discharge port 7 is provided so as to be located in the vicinity of the adhesive fixing section 3, which serves both for draining the liquid to be treated and for discharging air. An outlet 8 for taking out filtered water filtered by the hollow fiber membrane bundle 2 is provided at the upper end of the housing 1 so as to be located on the opposite side of the adhesive fixing portion 3.

The lower end of the protective cylinder 4 is cut off obliquely, so that the cylindrical surface is longer on the side facing the discharge port 7 and shorter on the opposite side. The short side of this cylindrical surface has a minimum distance L of at least 10 from the inner surface of the adhesive fixing portion 3.
mm, the cylinder surface of the protection cylinder 4 in this area is a closed surface of the whole area, so that fluid cannot move into and out of the protection cylinder. The area below the shortest distance L is the opening 4
Since it becomes o, the fluid can move freely inside and outside of the protection cylinder. The area of the opening 4o is set within a range of 10 to 60 mm from the inner surface of the adhesive fixing section 3.

By providing the protective cylinder 4 having the above structure,
An air pool is formed in a cylindrical closed surface region having the shortest distance L, that is, a cylindrical closed surface region at least 10 mm from the inner surface of the adhesive fixing portion 3. Since there is no water to be treated in this air reservoir during a normal filtration operation, suspended matter in raw water does not adhere to the membrane surface of the hollow fiber membrane, and the hollow fiber membrane does not deteriorate.

In the opening 4o below the shortest distance L, the fluid freely moves in and out, so that during the air scrubbing, only a slight swing is allowed while limiting the excessive swing of the hollow fiber membrane bundle 2. Therefore, the suspended substance does not adhere to the membrane surface. In addition, since excessive vibration does not reach the fixed end of the hollow fiber membrane bundle 2, breakage due to shearing force can be prevented.

As shown in FIG. 1B, in the cross section of the protective tube 4 passing through the center of the inlet of the discharge port 7, the opening 4o has the center O of the cross section of the protective tube 4 and the inlet of the discharge port 7. ± 30 from the center O to the line segment A connecting the center
It is desirable that it be present in the portion of the protective cylinder excluding the region facing each other. With such an arrangement of the opening 4o, it is possible to effectively prevent the hollow fiber membrane from being sucked into the outlet 7 during air scrubbing.

FIGS. 2A and 2B show another embodiment of the present invention. This embodiment has the same configuration as that of FIG. 1 except that the opening 4o provided in the protective cylinder 4 is configured as an aggregate of a plurality of holes. The distance of the opening 4o from the inner surface of the adhesive fixing portion 3 is set so that the shortest distance L is at least 10 mm, and the area where the opening 4o is provided is within a range of 10 to 60 mm from the inner surface of the adhesive fixing portion 3. Set as is.

In the case of this embodiment as well, as in the case of FIG. 1, air is trapped in the cylindrical closed surface region having the shortest distance L, so that suspended matter in the raw water is deposited on the surface of the hollow fiber membrane. There is no adhesion, and no deterioration of the hollow fiber membrane occurs. Also,
In the opening 4o, the fluid moves freely in and out, so that excessive swinging of the hollow fiber membrane bundle 2 during air scrubbing is limited, and only slight shaking can be performed, so that suspended matter can adhere to the membrane surface. No excessive shaking is caused by the hollow fiber membrane bundle 2
It is also possible to prevent breakage or the like due to shearing force from reaching the fixed end of the.

Further, as shown in FIG.
In the cross section of the protective cylinder 4 passing through the center of the inlet of the discharge port 7, a line segment A connecting the center O of the cross section of the protective cylinder 4 and the center of the inlet of the discharge port 7 is ±± from the center O. It is preferable that the hollow fiber membrane is arranged in a portion of the protective cylinder except for a region facing each 30 °, so that the hollow fiber membrane is not sucked into the outlet 7.

The hollow fiber membrane module of the present invention has a structure in which a large number of porous hollow fiber membranes are loaded in a housing, a solid-liquid mixed liquid is introduced into the module, and solid-liquid separation can be performed by the hollow fiber membrane surface. Then, the shape is not particularly limited. Generally, a structure is used in which at least one end of the hollow fiber membrane bundle is adhesively fixed together with a housing with an adhesive, and the adhesive fixing portion is cut to open the inside of the hollow fiber membrane. In this structure, the hollow fiber membrane is linearly arranged in the housing, and one end or both ends are fixed together with the housing, or the hollow fiber membrane is U-shaped as in the embodiment of FIGS. And one end is fixed together with the housing.

The size of the housing constituting the hollow fiber membrane module of the present invention is not particularly limited. However, from the viewpoint that the module can be easily manufactured and the module can be relatively easily handled, the housing diameter is 50 to 600.
mm, and the length may be conveniently selected from the range of 20 to 2500 mm. The material of the housing may be any of metal and resin. As the resin, preferably, an acrylic resin, a vinyl chloride resin, polysulfone, modified polyphenylene oxide, a polycarbonate resin and the like are suitable.

The hollow fiber membrane used in the hollow fiber membrane module of the present invention is not particularly limited as long as it is a porous hollow fiber membrane. Examples of the hollow fiber membrane include polyethylene, polypropylene, polysulfone, polyether sulfone, polyvinyl alcohol, cellulose acetate, and cellulose acetate. Polyacrylonitrile and other materials can be selected. The pore diameter of the hollow fiber membrane surface is not particularly limited either, but is preferably 0.001 μm to 1 μm.
Can be conveniently selected within the range. Further, the outer diameter of the hollow fiber membrane is not particularly limited, either.
The range of 000 μm is preferable because the swingability of the hollow fiber membrane is high and the hollow fiber membrane has excellent cleaning properties.

The adhesive for liquid-tightly adhering the housing and the hollow fiber membrane is not particularly limited, but a thermosetting resin such as an epoxy resin or a urethane resin can be preferably used. The protection cylinder is a structure surrounding the outer periphery of the hollow fiber membrane bundle, and the fixing method is not particularly limited. Preferably, it is suitable to be fixed in the module together with the hollow fiber membrane bundle with an adhesive or adhered to the inner surface of the housing.

The shape of the protective cylinder is not particularly limited as long as it can surround the outer peripheral portion of the hollow fiber membrane bundle loaded in the module, but is preferably a cylindrical shape. The term “cylindrical” means that the cross-section perpendicular to the axis has a circular, elliptical or similar shape. With this cylindrical protection cylinder, damage to the hollow fiber membrane due to contact between the protection cylinder and the hollow fiber membrane can be reduced.

The cylindrical surface of the protective cylinder is at least 10 mm, preferably 10 mm to 60 mm from the inner surface of the adhesive fixing portion.
The shape is not particularly limited as long as the surface up to the position within the range is closed and the shape does not allow fluid to flow out. Preferably, the cylindrical lower end is partly cut off as an opening, in particular, FIG.
It is preferable that the shape is cut obliquely at about 30 ° with respect to the direction orthogonal to the axis.

Further, as shown in FIG. 2, a cylindrical protective cylinder may be provided with an opening having a large number of holes. The cylindrical surface has a closed surface at least 10 mm from the inner surface of the adhesive fixing portion to prevent the fluid from moving in and out, and has an opening formed with a number of holes below the closed surface area, so that the fluid can be moved in and out. It can be so.

The length of the closed surface of the protection cylinder is set to be 1
If it is shorter than 0 mm, it becomes difficult to form an air pocket near the adhesive fixing portion. The closed surface length is 60mm
If the length is longer than that, in the case of a structure in which the fluid flows out, if the supply flow rate is 0.1 to 5.0 m ³ / m ² per module cross-sectional area usually supplied in the module,
Since an air reservoir can be formed, there is a great disadvantage that the effective membrane area contributing to filtration is reduced.

The material of the protective cylinder may be metal or resin, but from the viewpoint of reducing damage to the hollow fiber membrane, resins such as acrylic resin, vinyl chloride resin, polysulfone, modified polyphenylene oxide, and polycarbonate resin are used. preferable.

[0029]

EXAMPLES Example 1 Outer diameter 680 μm, inner diameter 400 μm, average pore diameter 0.01
A hollow fiber membrane bundle consisting of 3500 μm polyacrylonitrile porous hollow fiber membranes is bundled in a U-shape, and both ends thereof have an outer diameter of 85 mm and an inner diameter of 82 mm, which are 1 mm from the end on the side of the adhesive fixing section.
Eight holes at 5 mm and eight at 30 mm are inserted into a protection tube, and the protection tube is bundled with a hollow fiber membrane bundle bundled in a U-shape together with hard vinyl chloride having an outer diameter of 110 mm and an inner diameter of 104 mm. After being inserted into the housing of the pipe and fixing one end with an adhesive, a part of the adhesive fixing part was cut to open the inside of the hollow fiber membrane.

The protective cylinder at this time has a length extending from the adhesive fixing portion to 40 mm, and the position of the hole (opening) on the protective cylinder surface is adjusted from the center O of the cross section of the protective cylinder to the air outlet of the housing. Of the line segment passing through the center of the entrance, and was arranged in a portion excluding a range of ± 30 ° left and right from the center O thereof. At the bottom of the housing, 8 with a total area of 60 mm ²
An air injection unit having a plurality of injection ports is horizontally arranged, and has a shape length of 1100 mm and a hollow fiber membrane effective length of 8 as shown in FIG.
A 00 mm hollow fiber membrane module was manufactured.

The hollow fiber membrane module is supplied with 30 liter / min of pure water for 30 seconds, filtered for 13 minutes, air scrubbed with 30 liter / min of air for 1 minute, and filtered for 1 cycle of 30 seconds of drainage. Was carried out continuously for 2 months, but no damage of the hollow fiber membrane occurred near the adhesive fixing portion.

Example 2 Outer diameter 680 μm, inner diameter 400 μm, average pore diameter 0.01
A hollow fiber membrane bundle composed of 3500 μm polyacrylonitrile porous hollow fiber membranes is bundled in a U-shape, and both ends of the bundle are angled with respect to a plane perpendicular to the axis with the lower end of a cylindrical material having an outer diameter of 85 mm and an inner diameter of 82 mm. It is inserted into the protective cylinder cut obliquely at 30 °, inserted into the housing of a hard vinyl chloride pipe having an outer diameter of 110 mm and an inner diameter of 104 mm, and one end thereof is fixed with an adhesive. A part was cut to open the inside of the hollow fiber membrane.

At this time, the shortest distance from the inner surface of the adhesive fixing portion at the inclined lower end of the protective cylinder was 40 mm, and the shortest distance was located on the side opposite to the air discharge port. An air jet unit having eight jet ports with a total area of 60 mm ² is horizontally arranged at the lower part of the housing, and a hollow fiber membrane having a length of 1100 mm and a hollow fiber effective length of 800 mm as shown in FIG. I made a module.

The hollow fiber membrane module is supplied with pure water at a rate of 30 l / min for 30 seconds, filtered for 13 minutes, air scrubbed with air at 30 l / min for 1 minute, and filtered with 1 cycle of drainage for 30 seconds. Was carried out continuously for 2 months, but no damage of the hollow fiber membrane occurred near the adhesive fixing portion.

Comparative Example 3 In the hollow fiber membrane module of Example 1, except that the number of holes (openings) of the protective tube was changed to 8 at a position of 2 mm from the inner surface of the adhesive fixing portion and to 8 at a position of 20 mm. A hollow fiber membrane module having a similar structure was manufactured.

When the filtration operation of this hollow fiber membrane module was continuously performed for two months under the same conditions as in Example 1, thirteen hollow fiber breaks occurred in the hollow fiber membrane near the adhesive fixing portion. .

[0037]

As described above, according to the present invention, although the protection cylinder for suppressing the vibration of the hollow fiber membrane during the air scrubbing is provided, the fluid flows through the cylinder surface from the adhesive fixing portion to at least 10 mm. Since the closed surface is not allowed and an opening that allows free circulation is provided in the range of 10 to 60 mm, the air that has entered the protective cylinder is formed into an air pocket in a region at least 10 mm from the adhesive fixing portion, and this air is formed. In order to prevent suspended matter from accumulating due to accumulation, the hollow fiber membrane is prevented from deteriorating due to deposits in the vicinity of the adhesive fixing portion, and the hollow fiber membrane is not broken due to the deterioration.

[Brief description of the drawings]

1A is a longitudinal sectional view showing an embodiment of a hollow fiber membrane module of the present invention, and FIG. 1B is a sectional view taken along line XX in FIG. 1A.

2A is a longitudinal sectional view showing another embodiment of the hollow fiber membrane module of the present invention, and FIG.
FIG. 4 is a cross-sectional view as viewed in the direction of arrow Y.

FIG. 3 is a longitudinal sectional view showing an example of a conventional hollow fiber membrane module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Hollow fiber membrane bundle 3 Adhesion fixing part 4 Protective cylinder 4o Opening 5 Supply port (for liquid to be treated) 6 Air injection port (nozzle) 7 (Common use of water to be treated and air)

Claims (4)

[Claims] 1. An adhesive fixing part to which at least one end of a number of hollow fiber membrane bundles is fixed is fixed to an upper part of a housing, and a periphery of the fixed end of the hollow fiber membrane bundle is covered with a protective cylinder extending from the adhesive fixing part. In a hollow fiber membrane module provided with an air injection port for air scrubbing at a lower portion of the housing and an air discharge port provided near an adhesive fixing portion at an upper portion of the housing, the cylindrical surface of the protective cylinder is at least 10 mm from the adhesive fixing portion. A hollow fiber membrane module having a closed surface through which fluid cannot flow, and an opening which can flow freely within a range of 10 to 60 mm from the adhesive fixing portion. 2. In a cross section of the protective cylinder passing through the center of the inlet of the air discharge port, the opening is formed with respect to a line connecting the center O of the cross section of the protective cylinder with the center of the inlet of the air discharge port. 2. The hollow fiber membrane module according to claim 1, wherein the hollow fiber membrane module is arranged in a portion of the protective cylinder except for a region that faces left and right by ± 30 ° from the center O. 3. 3. The hollow fiber membrane module according to claim 1, wherein the opening has a structure in which a part of a lower end of the protection cylinder is cut off. 4. The hollow fiber membrane module according to claim 1, wherein the opening is a large number of holes penetrating the cylinder surface of the protection cylinder.