JP2007044666A - Hollow fiber membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow fiber membrane module which can be effectively washed in accordance with raw water quality and an operation method even when the immersion type hollow fiber membrane module having both ends fixed by adhesion is longitudinally installed. <P>SOLUTION: The hollow fiber membrane module is used as follow; adhesion fixation parts made by adhesion-fixing both ends of hollow fiber membrane bundle comprising a plurality of hollow fiber membranes are connected with each other by a stay and, upon membrane filtration operation, the adhesion fixation parts of the both ends are arranged and used substantially in the vertical direction, wherein a distance between the adhesion fixation parts of the both ends can be changed by adjusting the stay. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to the structure of a hollow fiber membrane module, and more specifically, by adjusting stays that connect the adhesive fixing portions at both ends of a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes, The present invention relates to a hollow fiber membrane module capable of changing a distance between adhesive fixing portions at both ends.

  The membrane separation method has features such as energy saving, space saving, labor saving, and product quality improvement, and therefore, its use in various fields is expanding. For example, a microfiltration membrane or an ultrafiltration membrane can be applied to a water purification process for producing industrial water or tap water from river water, groundwater or sewage treated water.

  Furthermore, since the hollow fiber membrane module can secure a large membrane area per unit volume, it can be used in many fluid processing fields, for example, concentration / desalting of enzymes using ultrafiltration membranes, production of water for injection, and electrodeposition coating. It is applied to the recovery of wastewater, final filtration of ultrapure water, sewage treatment, turbidity of river water, lake water, and underground water, chemical purification by microfiltration membrane, sterilization, turbidity, etc.

  However, when raw water is filtered through a membrane, the removal object such as turbidity and organic matter contained in the raw water accumulates on the membrane surface, and the membrane clogging phenomenon occurs. become unable. Therefore, it is necessary to wash the membrane in order to maintain the membrane filtration performance. For membrane cleaning, membrane filtration is stopped, gas is supplied to the hollow fiber membrane in the water, and the hollow fiber membrane is vibrated to remove dirt attached to the membrane surface. In order to discharge the turbidity separated by air scrubbing or backflow cleaning out of the module system efficiently, backwashing is performed by backflowing filtered water or clarified water with a pump or the like from the direction opposite to the filtration direction. A method of extruding turbidity out of the system by discharging the entire amount out of the module system or supplying a certain amount of raw water. The process of subjecting the raw water to membrane filtration is called a filtration process, and a process in which all cleaning operations such as air scrubbing, backwashing, and turbid discharge are combined into a series of processes is called a washing process. Performing the filtration step and the washing step once each is called one cycle, and generally in the operation of the hollow fiber membrane module, this cycle is generally repeated and performed automatically.

  The hollow fiber membrane module is roughly classified into a pressure type hollow fiber membrane module and an immersion type hollow fiber membrane module. The pressurization type hollow fiber membrane module is loaded with a large number of porous hollow fiber membrane bundles in a pressure-resistant cylindrical case, and both ends of the membrane bundle and the cylindrical case are bonded and fixed. The membrane module has a structure in which the inside of the yarn membrane is opened, and the pressurized raw water is introduced into the module and filtered through the hollow fiber membrane surface. On the other hand, the submerged membrane module has a structure in which both end portions of the hollow fiber membrane bundle are bonded and fixed with an adhesive, and the adhesive fixing portion is cut to open the inside of the hollow fiber membrane. It is a membrane module that employs a suction filtration method in which a membrane module is immersed in water and the permeate side is suctioned and filtered.

  The pressurization type hollow fiber membrane module has the advantages that the filtration pressure can be set higher than that of the immersion type, so that the throughput per membrane area increases, so the number of membranes required for the treatment can be reduced and the installation area can be reduced. have. On the other hand, the submerged hollow fiber membrane module has no cylindrical case and only has the membrane immersed in the treated raw water, so it is excellent in discharging turbidity clogged between the membranes, and membrane filtration is possible even in highly turbid raw water. There is an advantage that can be done. Moreover, since the filtration method is simple and there are few incidental piping, there also exists an advantage which can reduce an installation cost.

  Generally, when a submerged hollow fiber membrane module with both ends bonded and fixed is placed vertically, that is, when the adhesive fixing portions at both ends are arranged in the vertical direction and the filtration operation is performed, the hollow fiber membrane module depends on the weight of the lower end adhesive fixing portion. The upper adhesive fixing part and the lower adhesive fixing part are connected by a stay so that the hollow fiber membrane is not broken. The length of the stay is determined when the module is created, and is not changed thereafter. For this reason, the degree of loosening of the hollow fiber membrane is also determined at the time of module creation and is unchanged thereafter.

  However, in the operation of the hollow fiber membrane module, the above-described looseness of the hollow fiber membrane is an important know-how, and in the case of a pressurized hollow fiber membrane module, in order to perform efficient air scrubbing, the formula [ (LD) / D] × 100 (where L is the length of the hollow fiber membrane between the adhesive fixing portions at both ends, and D is the length between the adhesive fixing portions at both ends). Has been disclosed (for example, see Patent Document 1). In the case of a pressurized hollow fiber membrane module, generally, when the amount of slack is small during air scrubbing, the free fluctuation of the hollow fiber membrane is hindered and the cleaning effect is reduced, and the amount of slack is too large. Is said that the hollow fiber membrane lifted by air bubbles during air scrubbing comes into a meandering state by contacting the cylindrical case a plurality of times, and the free movement is also hindered, so that the cleaning effect is lowered.

  On the other hand, even in the case of an immersion-type hollow fiber membrane module, a technique relating to setting the looseness rate to 0 to 3% is disclosed (for example, see Patent Document 2). In general, when the amount of slack is small at the time of air scrubbing, as with the pressurization type, there is a problem that the free fluctuation of the hollow fiber membrane is hindered and the cleaning effect is reduced, and when the amount of slack is too large In the water, the hollow fiber membrane swings greatly due to buoyancy, but requires a larger amount of air, and the potting resin curing that fixes the hollow fiber membrane focusing end by the large swing of the hollow fiber membrane As a result of increased stress due to buckling at the base and the base of each individual hollow fiber membrane, the strength of the interface decreases, resulting in cracks and breakage of the hollow fiber membrane in the vicinity of the cured resin part, and module functions with short-term use It is said that there will be problems such as causing disappearance. Also, when the turbidity peeled off from the membrane surface is discharged from between the membranes by physical cleaning such as air scrubbing, in the case of the same filling rate, the larger the slack, the more easily the turbidity is discharged from between the membranes. It is said that the space required for this will increase and the amount of air required will also increase.

  From the above background, when raw water is highly turbid, increase the amount of membrane slack to increase air scrubbing and turbidity discharge, and when raw water is clear and when Ideally, the installation space is reduced and the amount of air is reduced by setting the amount of slackness of the membrane small. Also, in the operation method, when the membrane filtration conditions are severe, such as when operating at a high recovery rate or when operating with a high membrane filtration flux that sets a large filtration rate per unit membrane area, the amount of membrane slack is reduced. It is ideal to set a large amount and set the membrane slack amount small when operating at a low recovery rate or when operating at a low membrane filtration flux.

  In other words, there is an optimum amount of slack for each raw water quality and operation method, but as described above, when the submerged hollow fiber membrane module with both ends bonded and fixed is subjected to a filtration operation, the hollow fiber membrane module is It has a structure in which the adhesive fixing part and the lower adhesive fixing part are connected by a stay, and the length of the stay and the distance between both adhesive fixing parts are determined at the time of module creation, and are not changed thereafter. The actual condition is that the slackness is determined at the time of creating the module and remains unchanged thereafter.

On the other hand, when the immersion type hollow fiber membrane module with both ends bonded and fixed is placed horizontally, that is, when the filtration fixing operation is performed with the bonding fixing portions at both ends arranged in the horizontal direction, a stay for connecting both the bonding fixing portions is not necessarily required. Therefore, it is possible to set the optimum amount of slack for each raw water quality and operation method, and it is also possible to carry out membrane filtration operation while changing the amount of slack (see, for example, Patent Document 3). .
Japanese Patent Laid-Open No. 10-339 JP-A-11-97034 JP-A-9-206565

  However, when performing the filtration operation with the adhesive fixing parts at both ends not connected with the stay, it is necessary to be more careful in handling than when connecting with the stay and performing the filtration operation in the vertical position. There is a problem that the installation area increases, and the amount of air necessary for cleaning increases.

  That is, the present invention provides a hollow fiber membrane module that can be effectively washed according to the raw water quality and operation method even when the immersion hollow fiber membrane module having both ends bonded and fixed is vertically installed. For the purpose.

  The present invention for solving the above-described problems has the following configuration.

  (1) Adhesive fixing portions in which both ends of a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes are bonded and fixed are connected by a stay, and the adhesive fixing portions at both ends are substantially vertical when performing membrane filtration operation. A hollow fiber membrane module used so as to be arranged, wherein the distance between the adhesive fixing portions at both ends can be changed by adjusting the stay.

(2) By changing the distance between the adhesive fixing portions at both ends, the sag rate r [%] = [(LD) / D] × 100,
0 <r ≦ 10
The said hollow fiber membrane module is comprised so that it can change within the range of this.
(However, L: the length of the hollow fiber membrane between the adhesive fixing portions at both ends, D: the length between the adhesive fixing portions at both ends.)

  According to the present invention, the distance between the adhesive fixing portions at both ends can be changed by adjusting the stay that connects the adhesive fixing portions of the hollow fiber membrane module used in a vertical position. Therefore, the amount of slack in the hollow fiber membrane can be set to the optimum amount according to the quality of raw water and the operation method, sufficient cleaning can be performed with the minimum amount of air, and stable operation for a longer period of time. Can be carried out.

  In addition, when the adhesive fixing parts are connected by a plurality of stays, if there is a variation in local membrane filling rate and there is a bias in the air flow, each stay is adjusted and the side with less air flow By making the distance between the two adhesive fixing parts longer than the side where there is a lot of air flow, it is possible to correct the air flow unevenness, perform sufficient cleaning with a small amount of air, and perform stable operation for a longer period of time. .

  The present invention is used so that the adhesive fixing portions at both ends are arranged in a substantially vertical direction when performing a membrane filtration operation. Adhesive fixing portions in which both ends of a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes are adhesively fixed. Are hollow fiber membrane modules connected by stays.

  When performing the membrane filtration operation, the adhesive fixing portions at both ends are arranged in a substantially vertical direction, when performing a membrane filtration operation comprising a series of steps including a filtration step and a washing step using the hollow fiber membrane module of the present invention, This means that the hollow fiber membrane module is placed vertically, that is, it is installed such that the adhesive fixing portions at both ends constituting the hollow fiber membrane module are substantially aligned in the vertical direction. Here, the phrase “installed so that they are substantially aligned in the vertical direction” is preferably installed so that they are aligned in the vertical direction. However, when the hollow fiber membrane module of the present invention is installed and air scrubbed, This means that it is only necessary to arrange the bubbles so as to rise along the direction in which the thread membrane bundle extends.

  In the present invention, it is essential that the distance between the adhesive fixing portions at both ends can be changed by adjusting the stay. By adopting such a configuration, it is possible to arbitrarily set the amount of looseness of the hollow fiber membrane, so it is possible to set the optimum amount of hollow fiber membrane slack according to the raw water quality and operation method, and the minimum necessary amount A sufficient amount of air can be used for cleaning, and stable operation can be performed for a longer period of time.

  In the present invention, the slackness ratio r [%] = [(LD) / D] × 100 can be changed within the range of 0 <r ≦ 10 by adjusting the stay. It is preferable that it is configured so that it can be changed within a range of 0.01 ≦ r ≦ 3. Here, L means the length of the hollow fiber membrane between the adhesive fixing portions at both ends of the hollow fiber membrane module, and D means the length between the adhesive fixing portions at both ends of the hollow fiber membrane module. If the slack rate is as close as possible to 0%, the vibration of the hollow fiber during air scrubbing is restricted, and the cleaning effect is reduced. If the slack rate exceeds 10%, the amount of slack in the membrane becomes unnecessarily large. The contact area with the bubble is reduced, the cleaning effect is reduced, and the buckling stress at the adhesive fixing part for fixing the converging end of the hollow fiber membrane and the adhesive part of each hollow fiber membrane becomes very large, and the interface part This is because the possibility that the hollow fiber membrane is cracked or broken near the adhesive fixing portion becomes very high as a result of the decrease in the strength of the adhesive.

  Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings. However, the scope of the present invention is not limited to these.

  FIG. 1 is a cross-sectional view showing an embodiment of a submerged hollow fiber membrane module according to the present invention, and FIG. 2 is an enlarged view for explaining a configuration of a hollow fiber membrane module lower adhesive fixing portion. In FIG. 1, in the present invention, the upper part of the hollow fiber membrane bundle 1 is integrally coupled and fixed in the cartridge head 2. The hollow fiber membrane 1 on the cartridge head 2 side has an open end. The lower part of the hollow fiber membrane bundle 1 is integrally bonded and fixed in the skirt 3, and the end of the hollow fiber membrane 1 on the skirt 3 side is sealed. As illustrated in FIG. 2, the skirt 3 is formed with a plurality of through-holes 3 b for introducing the air discharged from the air diffuser into the hollow fiber membrane bundle so as to effectively contact the outer peripheral surface of each hollow fiber membrane. ing.

  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, but polyacrylonitrile, polyphenylene sulfone, polyphenylene sulfide sulfone, polyvinylidene fluoride, polypropylene, polyethylene, polysulfone In addition, it preferably contains at least one selected from the group consisting of inorganic materials such as polyvinyl alcohol, cellulose acetate and ceramic, and more preferably contains polyvinylidene fluoride from the viewpoint of film strength. The pore diameter on the surface of the hollow fiber membrane is not particularly limited, but can be conveniently selected within the range of 0.001 μm to 1 μm. The outer diameter of the hollow fiber membrane is not particularly limited, but is preferably in the range of 250 μm to 2000 μm because the hollow fiber membrane has high oscillating properties and excellent cleaning properties. Further, the adhesive for adhering and fixing the both end portions of the hollow fiber membrane bundle with an adhesive is not particularly limited, but it is preferable to use a thermosetting resin such as an epoxy resin or a urethane resin.

  The cartridge head 2 serves as a fixing portion when the hollow fiber membrane cartridge is suspended from the immersion type filtration device, and also serves as a sealing portion that separates the raw water from the filtrate, so that the cartridge head 2 has a suspension, fixing, and sealing function. It has a shape with both. For example, a step may be provided on the outer peripheral portion, a groove may be provided, or a brim portion protruding radially outward may be provided. The sectional shape of the cartridge head 2 in the radial direction may be a circle, a square, a hexagon, an ellipse, or the like. Therefore, a circular shape is preferable.

The through-hole 3b provided in the lower adhesive fixing part 3a on the skirt side of the present invention is a hole opened in the adhesive fixing part itself, and this through-hole is usually formed in the lower adhesive fixing part although it depends on the cross-sectional area of the module. For example, it is preferable to arrange 5 to 20 pieces per 0.01 m ² of the cross-sectional area of the adhesive fixing portion. The individual opening area of such a through hole depends on the hollow fiber membrane diameter and the number of through holes, but is selected from the range of 3 to 800 mm ² , for example, the diameter of the hollow fiber membrane is 1 to 1.5 mm, When the number of through holes per cross-sectional area of 0.01 m ² is 5 to 20, the opening area of each through hole is preferably 20 to 150 mm ² . The shape of the opening is selected from a polygon such as a triangle, a quadrangle, and a hexagon, a circle, an ellipse, a fan, a C-shape, or a star. The positions of the through holes are distributed on the adhesive fixing cross section, for example, at the intersection of multiple circles and radial lines, the intersection of the grids, or the positions of the vertices of many equilateral triangles. It is preferable to provide it, and it is particularly preferable to provide a large amount at the center of the hollow fiber membrane bundle.

  In the present invention, the skirt 3 preferably protrudes from the end portion of the hollow fiber membrane bundle 1 and is bonded and fixed to the hollow fiber membrane bundle to form an air chamber 3c surrounded by the adhesive fixing portion and the skirt. The length of the skirt 3 protruding from the end surface of the hollow fiber membrane depends on the diameter of the cartridge, the amount of gas to be supplied, and the diameter and number of the through holes, but is preferably 5 mm to 200 mm in order to prevent gas dissipation. The cross-sectional shape of the skirt 3 in the radial direction may be a circle, a quadrangle, a hexagon, an ellipse, or the like. However, when the cartridge is mounted on the filtration tank, it may be the same shape as the cartridge head. A circular shape is particularly preferable.

In the hollow fiber membrane module of the present invention, the adhesive fixing part (upper adhesive fixing part) on the cartridge head 2 side and the adhesive fixing part (lower adhesive fixing part) on the skirt 3 side are connected and fixed by the stay 4, and both It is a hollow fiber membrane module which performs membrane filtration operation by arranging an adhesive fixing portion in a substantially vertical direction. The material for the stay 4 for connecting and fixing is not particularly limited, such as stainless steel and vinyl chloride. As for the shape of the stay 4, the center point between the adhesive fixing portions is preferably selected from a cross-sectional area of 3 to 700 mm ^2, and is preferably connected to the outer peripheral portion of the membrane bundle and the adhesive fixing portion. Preferably, ² to 30 cylindrical stays selected from an area of 3 to 700 mm ² are arranged, and a structure for connecting the adhesive fixing portions at both ends, a knitted material such as a net is wound around the outer peripheral portion of the adhesive fixing portion, There is no particular limitation on the structure, such as a structure for connecting the both-end adhesive fixing portions.

  As described above, the present invention is a hollow fiber membrane module in which both ends of a hollow fiber membrane bundle 1 composed of a plurality of hollow fiber membranes are bonded and fixed, and an upper adhesive fixing portion 2 and a lower adhesive fixing portion 3 are connected by a stay 4. In the membrane filtration operation, the hollow fiber membrane module is used by arranging the upper adhesive fixing portion 2 and the lower adhesive fixing portion 3 in a substantially vertical direction. It is a hollow fiber membrane module comprised so that the distance between fixing | fixed parts can be changed.

As a method of adjusting stay 4,
(1) Both ends of the stay 4 are screwed, screw holes are provided in a part of the upper adhesive fixing portion 2 and the lower adhesive fixing portion 3, and the length of the stay 4 between the upper adhesive fixing portion 2 and the lower adhesive fixing portion 3 Adjust the height (eg as shown in FIG. 3)
(2) The stay 4 is fixed only to the upper adhesive fixing portion 2, and the stay 4 penetrating the lower adhesive fixing portion 3 is fixed and adjusted from below the lower adhesive fixing portion 3 with a nut 5 or the like (for example, as shown in FIG. 4) )
(3) The length adjustable stay 4 is fixed to the both-end adhesive fixing portion (for example, as shown in FIG. 5).
There are methods. In addition, by adjusting the length of the stay 4 between the upper adhesive fixing portion 2 and the lower adhesive fixing portion 3, the means for setting the looseness ratio r [%] in the range of 0 <r ≦ 10 is the upper adhesive fixing. A portion for adjusting the length of the stay 4 between the portion 2 and the lower adhesive fixing portion 3, for example, when using the movable range of the nut 5 or the stay 4 with adjustable length, the movable range of the stay itself is For example, stoppers may be installed on the top and bottom of the stay so that the slackness is in the range of 0% to 10%.

  By providing a stay that can adjust the distance between the adhesive fixing portions at both ends by any one of the above methods, there is a local variation in the film filling rate, and there is a bias in the air flow. Even if the module has been created, adjust the stays and set the distance between the adhesive fixing parts at both ends on the side with less air flow to be longer than that on the side with more air flow. This makes it possible to correct the unevenness of the system, to perform sufficient cleaning with a small amount of air, and to perform stable operation for a longer period of time.

  The present invention can be applied not only to water treatment using a submerged hollow fiber membrane module, but also to sewage treatment or industrial wastewater treatment using a submerged hollow fiber membrane module. However, it is not limited to these.

It is sectional drawing which shows one preferable embodiment of this invention. It is an enlarged view in the lower adhesive fixing | fixed part which shows one preferable embodiment of this invention. It is a schematic diagram which shows one preferable embodiment of this invention. It is a schematic diagram which shows one preferable embodiment of this invention. It is a schematic diagram which shows one preferable embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane bundle 2 Cartridge head 3 Skirt 3a Lower adhesion fixing | fixed part 3b Through-hole 3c Air chamber 4 Stay 5 Nut

Claims (2)

Adhesive fixing parts in which both ends of a hollow fiber membrane bundle composed of a plurality of hollow fiber membranes are bonded and fixed are connected by a stay, and the adhesive fixing parts at both ends are arranged in a substantially vertical direction when performing membrane filtration operation. The hollow fiber membrane module is used so that the distance between the adhesive fixing portions at both ends can be changed by adjusting the stay. By changing the distance between the adhesive fixing portions at both ends, the slackness ratio r [%] = [(LD) / D] × 100,
0 <r ≦ 10
The hollow fiber membrane module according to claim 1, wherein the hollow fiber membrane module is configured to be changeable within a range.
(However, L: the length of the hollow fiber membrane between the adhesive fixing portions at both ends, D: the length between the adhesive fixing portions at both ends.)

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