JP2010227837A - Hollow fiber membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow fiber membrane module which suppresses an entanglement of small bundles due to a lengthwise movement of a hollow fiber membrane and enables a stable and continuous operation in an air scrubbing process for the hollow fiber membrane. <P>SOLUTION: The hollow fiber membrane module 1 comprises a cylindrical vessel 3 having an opening at the upper end and the lower end, in which at least a part of the peripheral wall consists of a porous member 3c, a plurality of small bundles 8 consisting of a plurality of hollow fiber membranes 2 each positioning in a vertical direction, a hollow fiber membrane fixing member 4a provided on the upper end part of the small bundles 8, which bundles small bundles 8 to fix them integrally in a state that the hollow part of the hollow fiber membrane 2 is opened, and is fixed to the cylindrical vessel 3 in a state of blocking the opening of the upper end of the cylindrical vessel 3, and a small bundle fixing member 4b provided on the lower end of the small bundles 8, which blocks a hollow part of the hollow fiber membrane 2 and is provided independently having mutually a distance for every small bundle 8. Further, the hollow fiber membrane module 1 includes a presser plate 9 having a first hole having a width which each small bundle 8 penetrates and the small bundle fixing member 4b does not penetrate, and a second hole which the small bundles don't penetrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hollow fiber membrane module that is immersed in a treated water tank containing raw water and filters raw water, that is, an immersion type hollow fiber membrane module. More specifically, the present invention relates to a hollow fiber membrane module that can be continuously operated over a long period of time without reducing the filtration performance of the hollow fiber membrane.

  In general, an immersion type hollow fiber membrane module is provided with a hollow fiber membrane module disposed in a treated water tank, and raw water containing suspended substances in the treated water tank is suction filtered through the hollow fiber membrane module to obtain permeated water. in use. The submerged hollow fiber membrane module generally includes a filtration process for a certain period of time, a backwash process in which treated water obtained during filtration is pressurized and supplied to the inside of the membrane, and the sludge adhering to the outside of the membrane is washed away, and those processes The compressed air is fed into the hollow fiber membrane module from below the hollow fiber membrane module, and the hollow fiber membrane is shaken to be subjected to an air scrubbing process for washing suspended substances adhering to the surface of the hollow fiber membrane.

  The hollow fiber membranes in the air scrubbing process are easily damaged with each other, and the pore diameter of the membrane is crushed due to abrasion of the membrane surface, and it is difficult to obtain a predetermined filtration flow rate. Therefore, as disclosed in Patent Document 1, it is convenient that a small bundle partition member that partitions the small bundle fixing member of the hollow fiber membrane is provided between the small bundle fixing members.

International Publication No. 2007/083460 Pamphlet

  However, in the structure of the hollow fiber membrane module described in Patent Document 1, the vertical movement of the hollow fiber membrane cannot be suppressed, and small bundles wound up by air scrubbing are entangled with each other, effective membrane area, and cleaning As a result, the transmembrane pressure difference increases, resulting in a problem that a predetermined filtration flow rate cannot be obtained. It is an object of the present invention to provide a hollow fiber membrane module that can suppress the entanglement of small bundles due to the longitudinal movement of the hollow fiber membrane in the air scrubbing step of the hollow fiber membrane and can stably operate continuously.

In order to achieve the above object, a hollow fiber membrane module of the present invention has any of the following configurations.
(1) A cylindrical container having openings at the upper and lower ends and at least a part of the peripheral wall made of a porous member, and a plurality of small containers each made up of a plurality of hollow fiber membranes positioned in the vertical direction The bundle is provided at the upper end of the small bundle, the hollow bundle of the hollow fiber membrane is opened and fixed as a bundle, and the upper end of the cylindrical container is closed. A hollow fiber membrane fixing member fixed to a cylindrical container, and provided at a lower end portion of the small bundle, the hollow portion of the hollow fiber membrane is closed, and the small bundles are spaced apart from each other independently. A hollow fiber membrane module comprising: a small bundle fixing member provided, wherein each of the small bundles penetrates, and the first hole has a width that does not penetrate the small bundle fixing member, A hollow having a pressing plate having a second hole through which the small bundle does not penetrate Yarn membrane module.
(2) The hollow fiber membrane module according to (1), wherein in the hollow fiber membrane module of the present invention, at least a part of an edge of the first hole is rounded.
(3) The hollow fiber membrane module according to (1), wherein in the hollow fiber membrane module of the present invention, at least a part of an edge of the first hole is covered with a cushioning material.

  According to the hollow fiber membrane module of the present invention, the vertical movement of the hollow fiber membrane by compressed air for air scrubbing supplied from below the hollow fiber membrane module is suppressed, and the entanglement between small bundles due to winding is prevented. I can do it.

It is a schematic longitudinal cross-sectional view of an example of the hollow fiber membrane module of this invention. It is an expanded view of the surrounding wall of the cylindrical container of the hollow fiber membrane module shown in FIG. FIG. 3 is an enlarged view of a part of the peripheral wall shown in FIG. 2. It is a perspective view of an example of the small bundle fixing member of the hollow fiber membrane module shown in FIG. It is a top view of the pressing plate shown in FIG. It is a front view of an example of the 1st hole of the pressing board shown in FIG. It is a front view of another example of the 1st hole of the holding plate shown in FIG. It is a schematic flowchart of the filtration operation apparatus used in the Example.

  The hollow fiber membrane module of this invention is demonstrated below, referring drawings.

  FIG. 1 is a schematic longitudinal sectional view of an example of the hollow fiber membrane module 1 of the present invention. In FIG. 1, the hollow fiber membrane module of the present invention has an opening 3a at the upper end and an opening 3b at the lower end, and a cylindrical container 3 in which at least a part of the peripheral wall is made of a porous member 3c. A plurality of small bundles 8 each consisting of a plurality of hollow fiber membranes 2 and a small bundle 8 provided at the upper end of the small bundle 8 with the hollow portion 2a of the hollow fiber membrane 2 open. The hollow fiber membrane fixing member 4a fixed to the cylindrical container 3 in a state of closing the upper end opening 3a of the cylindrical container 3 and the hollow fiber The hollow portion 2a of the membrane 2 is a hollow fiber membrane module 1 comprising a small bundle fixing member 4b that is independently provided with a gap 4bc for each small bundle 8, and the small bundle 8 Each of the push holes has a first hole 9a having a width not penetrating through the small bundle fixing member 4b and a second hole 9b through which the small bundle 8 does not penetrate. Even a plate 9 is provided. A specific mode (plan view) of the presser plate 9 is shown in FIG.

  In FIG. 1, each small bundle fixing member 4b is provided in an independent state at the lower end portion of each small bundle 8 depending from the hollow fiber membrane fixing member 4a, and each position is a fluid passing through the gap 4b. It can be changed by (stock solution or air scrubbing air).

  In the hollow fiber membrane module of the present invention, the hollow fiber membrane closing member that closes the hollow portion at the lower end of the hollow fiber membrane has a gap like the hollow fiber membrane closing member 4b of the hollow fiber membrane module 1 of FIG. Thus, the plurality of independent small bundle fixing members 4b are formed.

  In the hollow fiber membrane module of the present invention, the filtration region of the hollow fiber membrane has a membrane surface region in which the stock solution in contact with the outer surface of the hollow fiber membrane is filtered by the hollow fiber membrane and can flow into the hollow part of the hollow fiber membrane as filtered water. say.

  In the hollow fiber membrane module of the present invention, the hollow fiber membrane bundle is preferably composed of hundreds to tens of thousands of hollow fiber membranes.

  In the hollow fiber membrane module of the present invention, the number of hollow fiber membranes forming each small bundle is preferably from several tens to several thousand.

  In the hollow fiber membrane module of the present invention, the number of small bundles 8 is preferably any of 3, 7, and 19 that can be closely packed.

  The shape of each small bundle fixing member 4b is arbitrary, such as a cylindrical shape, a spherical shape, a conical shape, and a pyramid shape. The small bundle fixing member 4b in FIG. 1 is a cylindrical body.

  In the hollow fiber membrane module of the present invention, the number and diameter of the first holes 9a of the presser plate 9 are the number of divisions of the hollow fiber membrane bundle into a plurality of small bundles of hollow fiber membranes or one small bundle. The number of hollow fiber membranes may be selected so that the intended effect can be obtained. The shape of the first hole 9a is not particularly limited, but is preferably circular. Thereby, the damage of the film | membrane by the rub of the edge of the small bundle 8 and the 1st hole 9a can be reduced. Further, the area of the first hole 9a can be appropriately designed as long as the small bundle fixing member 4b does not penetrate and the hollow fiber membrane bundle penetrates.

  In the hollow fiber membrane module of the present invention, the number, diameter, and shape of the second holes 9b of the pressing plate 9 are not particularly limited, but considering the resistance that the air during air scrubbing gives to the pressing plate 9, the second holes The number of 9b is preferably 2 to 3000. Further, the total area of the second holes 9b is obtained by removing the total area of the first holes 9a from the cross-sectional area of the hollow fiber membrane module 1 in consideration of the resistance that the air during air scrubbing gives to the holding plate 9. It is preferable to occupy more in the area.

  Further, in order to obtain a desired effect according to the present invention, it is only necessary to prevent the hollow fiber membrane 2 from being rolled up in the vertical direction by the small bundle fixing member 4b penetrating the first hole 9a. In the present invention, the configuration is not limited as long as the small bundle fixing member 4b does not penetrate the first hole 9a. That is, as shown in FIG. 1, when the small bundle fixing member 4b is configured only in the form of a cylindrical body, the first hole 9a may be of a size that does not penetrate the cylinder, and the first hole Even if 9a is sized to penetrate the cylinder, for example, by attaching a rod-shaped projection to the lower part of the small bundle fixing member 4b of the cylindrical body, the small bundle fixing member 4b penetrates the first hole 9a. If there is no problem. In such a case, the small bundle fixing member 4b and the rod-shaped protrusion are collectively referred to as a small bundle fixing member.

  The material of the hollow fiber membrane in the hollow fiber membrane module of the present invention is not particularly limited. Examples of hollow fiber membrane materials include polysulfone, polyethersulfone, polyacrylonitrile, polyimide, polyetherimide, polyamide, polyetherketone, polyetheretherketone, polyethylene, polypropylene, ethylene-vinyl alcohol copolymer, cellulose, acetic acid Examples include cellulose, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, and composite materials thereof.

  The outer diameter of the hollow fiber membrane in the hollow fiber membrane module of the present invention is preferably 0.3 to 3 mm. If the outer diameter of the hollow fiber membrane is too small, the hollow fiber membrane is broken and damaged when handling the hollow fiber membrane when manufacturing the hollow fiber membrane module, and during filtration and washing when using the hollow fiber membrane module. It is easy for problems to occur. On the other hand, if the outer diameter is too large, the number of hollow fiber membranes that can be inserted into a cylindrical container of the same size is reduced, resulting in a problem that the filtration area is reduced. The film thickness of the hollow fiber membrane is preferably 0.1 to 1 mm. If the film thickness is too small, there is a problem that the film breaks due to pressure, and conversely, if the film thickness is large, problems such as pressure loss and an increase in material cost occur.

  The hollow fiber membrane fixing member 4a is usually formed from a resin. The hollow portion of each hollow fiber membrane is opened by letting a fluid resin flow between a large number of hollow fiber membranes and then solidifying the resin to fix the hollow fiber membrane and then cut the ends. In this state, the hollow fiber membrane fixing member 4a is formed. This forming operation is generally called potting and is widely known.

  The small bundle fixing member 4b is also usually made of resin. A flowable resin is allowed to enter the hollow portion of the hollow fiber membrane by a desired amount to fix the hollow fiber membrane with the same resin and to form a small bundle fixing member.

  As the resin for forming the hollow fiber membrane fixing member 4a and the small bundle fixing member 4b, an epoxy resin, a urethane resin, an epoxy acrylate resin, or the like, which is a general-purpose product, is inexpensive, and has little influence on water quality, is preferably used.

  The hollow fiber membrane module of the present invention is usually used for filtering raw water with a water collection cap 5 attached to the upper part of the cylindrical container and an air introduction cylinder 7 attached to the lower part. That is, in the hollow fiber membrane module 1, the filtered water flowing out from the opening of the hollow portion 2a of the hollow fiber membrane 2 is applied to the surface 4aF1 where the hollow portion 2a of the hollow fiber membrane 2 of the hollow fiber membrane fixing member 4a is open. A water collecting cap 5 for collecting water is attached to the cylindrical container 3. The water collecting cap 5 has a filtered water outlet 6 for leading the collected filtered water to the outside. An air introducing cylinder 7 for introducing air scrubbing air into the cylindrical container 3 is provided around the opening 3 b at the lower end of the cylindrical container 3.

  The cylindrical container 3, the water collecting cap 5, the air introduction cylinder 7, and the pressing plate 9 are usually formed from resin. Examples of the resin forming these include polyolefin resins such as polyethylene resin, polypropylene, and polybutene, polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), ethylene tetrafluoride / hexafluoropropylene (FEP) , Fluorinated resins such as ethylene tetrafluoroethylene (ETFE), ethylene trifluoride chloride (PCTFE), ethylene trifluoride ethylene chloride (ECTFE), vinylidene fluoride (PVDF), polyvinyl chloride, polyvinylidene chloride Chlorinated resins such as polysulfone resin, polyether sulfone resin, polyallyl sulfone resin, polyphenyl ether resin, acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylonitrile-styrene copolymer resin, polyphenylene sulfide resin, polyamide Resin, polycarbonate tree Fats, polyetherketone resins, polyetheretherketone resins and the like are used alone or in combination.

  The cylindrical container 3, the water collection cap 5, the air introduction cylinder 7, and the pressing plate 9 may be formed of a material other than resin. As the material in that case, aluminum, stainless steel or the like is preferably used. Furthermore, a composite material such as a resin-metal composite, a glass fiber reinforced resin, or a carbon fiber reinforced resin can also be used. The cylindrical container 3, the water collection cap 5, the air introduction cylinder 7, and the presser plate 9 may be formed of the same material or different materials.

  In the hollow fiber membrane module of the present invention, at least a part of the peripheral wall of the cylindrical container 3 is made of a porous member. An example of this will be described with reference to FIGS.

  FIG. 2 is a development view of the peripheral wall of the cylindrical container 3 in FIG. 1 and 2, at least a part of the peripheral wall of the cylindrical container 3 of the hollow fiber membrane module 1 of the present invention is composed of a porous member 3c having a mesh-shaped opening. The opening degree of the mesh can be appropriately adjusted in consideration of operating conditions and the like, for example, by making a difference between the opening ratio of the upper half and the opening ratio of the lower half of the cylindrical container 3. is there.

  FIG. 3 is a partially enlarged view of the peripheral wall of the cylindrical container 3. In FIG. 3, the peripheral wall is divided into an aperture portion 10 and a wire portion 11.

  As the porous member installed on the peripheral wall of the cylindrical container, a plate-like member having porosity such as a mesh shape, a net shape, or a punching metal shape can be used. For example, there are a plate-like member or a cylindrical member having a porosity formed by a resin, a metal net made of a metal wire, a punching metal plate, and the like. Among them, it is preferable to use a resin molded member having a porosity that is inexpensive and has little influence on water quality.

  FIG. 4 is an enlarged perspective view of the small bundle fixing member 4b in the hollow fiber membrane module 1 of the present invention shown in FIG. In FIG. 4, the small bundle fixing member 4b is formed of a cylindrical body made of resin. In the small bundle fixing member 4b, the small bundle 8 composed of a plurality of hollow fiber membranes 2 is fixed by resin, and the hollow portion at the lower end of each hollow fiber membrane is blocked by the resin that has entered the hollow portion. Yes.

  FIG. 5 is a plan view of the pressing plate 9 in the hollow fiber membrane module 1 of the present invention shown in FIG. In FIG. 5, the pressing plate 9 includes a plurality of first holes 9a through which each of the small bundles 8 penetrates and the small bundle fixing member 4b does not penetrate, and a plurality of first holes 9 through which each of the small bundles 8 does not penetrate. 2 holes 9b. With this structure, when the small bundle 8 is rolled up during air scrubbing, the upper portion of the small bundle fixing member 4b is caught by the lower portion of the pressing plate 9, and the small bundle 8 can be prevented from being rolled up.

  6 and 7 are examples of front views of the first hole 9a of the pressing plate shown in FIG. Regarding the first hole 9a, when the small bundle sways and collides with the edge of the first hole 9a, the edge corner as shown in FIG. 6 seems to have been lost in order to prevent the film surface from being damaged. It is preferable that the material is rounded or protected with a cushioning material 9aj so as to cover the corners of the edge as shown in FIG. The rounding method is not particularly limited, and various methods such as cutting and polishing can be employed. As the buffering agent, silicone rubber, natural rubber, synthetic natural rubber, styrene rubber, chloroprene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, hyperon rubber, acrylic rubber, urethane rubber, silicone rubber, fluorine rubber, etc. can be used. It is.

  As a method of installing the pressing plate 9, for example, there is a method of attaching the small bundle fixing member 4b to the lower portion of the hollow fiber membrane 2 after the small bundle 8 is passed through the first hole 9a of the pressing plate 9. In addition, a method for fixing the presser plate 9 to the cylindrical container 3 is not particularly limited, but a method for fixing using a bonding agent or the like is mentioned. In addition, the installation position of the pressing plate 9 is not particularly limited, but in order to prevent the small bundle 8 from winding around the lower part of the pressing plate 9, it can be fixed at a position of about 10 cm from the upper part of the small bundle fixing member 4b. preferable.

Example 1
A filtrate water pipe 22 is connected to the filtrate water outlet 6 of the hollow fiber membrane module 1 shown in FIG. 8 so that the filtrate water outlet 6 faces upward, and the inside of the aeration tank 13 containing raw water 12 and sludge 14 is hollow. The thread membrane module 1 is immersed, and the biologically-treated sludge 14 is sucked by the filtrate water pump 18 from the filtrate water outlet 6 side so that the pressure gauge 17 and the flow meter 19 are arranged as shown in FIG. The filtered water 20 was passed through, and the raw water 12 in the aeration tank 13 was filtered. Further, the filtered water 20 stored in the filtered water tank 21 was sucked by the backwash pump 24 and passed through the backwash water pipe 23 for backwashing. In the meantime, air was discharged from the air diffuser 15 by the blower 16 to perform air scrubbing of the hollow fiber membrane module 1.

  The hollow fiber membrane module 1 shown in FIG. 1 was used. As the hollow fiber membrane 2, a porous hollow fiber membrane made of polyvinylidene fluoride having an outer diameter of 1500 μm, an inner diameter of 900 μm, a small bundle number of 5, a small bundle diameter of about 20 mm, a small bundle fixing member 4b diameter of about 45 mm, and a length of about 2000 mm About 9000 were used. As the cylindrical container 3, a polypropylene container having an outer diameter of about 15 cm and a thickness of 3 mm was used. Epoxy resin was used as the hollow fiber membrane fixing member 4a and the small bundle fixing member 4b. ABS resin was used for the water collection cap 5 and the air introduction cylinder 7. As the presser plate 9, the diameter of the first hole 9a is set to 35 mm, the diameter of the second hole 9b is set to 3 mm, and the edge of the first hole 9a is rounded by R machining. Use the ones that have been applied, and use the adhesive at the position of 10 cm from the top of the small bundle fixing member 4b for the second holes 9b that are scattered in the holding plate 9 so that they are arranged evenly. And fixed to the inner wall of the cylindrical container 3. Further, the pressing plate 9 was made of polyethylene.

Next, the sludge in the tank containing raw water with an activated sludge concentration (MLSS) of about 5000 to 15000 is sucked for 9 minutes with a pump from the water collection cap 5 side, and filtered water of 0.6 m ³ / m ² / day. After that, backwashing was performed for 1 minute at 1.2 m ³ / m ² / day using the filtered water to produce 0.42 m ³ / m ² / day of filtered water as a total, and 100 L / min during that time. Air scrubbing was performed with two types of compressed air amounts of 200 L / min.

First, when operated for one week at an air volume of 100 L / min, the differential pressure increase rate is about 1.5 kPa / day, a predetermined filtration flow rate can be obtained, the hollow fiber membrane module 1 is pulled up, and the hollow fiber membrane is As a result of confirming the state of 2 and small bundle 8, no entanglement occurred. Thereafter, similar results were obtained even when the air amount was increased to 200 L / min.
(Comparative Example 1)
The same operation was performed using the same hollow fiber membrane module as in Example 1 except that the pressing plate 9 was not attached. As a result, when operating at an air amount of 100 L / min, the differential pressure increase rate was about 1.5 kPa / day, a predetermined filtration flow rate was obtained, and the small bundle 8 was not entangled. However, when operating with the air volume increased to 200 L / min, the differential pressure increase rate is about 40 kPa / day, and the predetermined filtration flow rate cannot be obtained, and the operation of the device stops in about 2 days. When the hollow fiber membrane module 1 was pulled up for confirmation, the small bundle 8 was wound around. From this, it can be seen that when the operation is performed using the presser plate 9, it is effective in suppressing the differential pressure increase rate.

  The hollow fiber membrane module of the present invention can be suitably used as a hollow fiber membrane module capable of continuous operation without deterioration of the filtration performance of the hollow fiber membrane for a long period in the field of sewage treatment or the like.

1: hollow fiber membrane module 2: hollow fiber membrane 2a: hollow portion of hollow fiber membrane 3: cylindrical container 3a: upper opening 3b of cylindrical container: lower opening 3c of cylindrical container: porous member 4a: hollow fiber Membrane fixing member 4aF1: surface 4b where the hollow portion of the hollow fiber membrane is open 4b: small bundle fixing member 4bc: gap between the small bundle fixing members 5: water collecting cap 6: filtrate outlet 7: air introduction tube 8: small Bundle 9: holding plate 9a: first hole 9ai: first hole 9aj with rounded edges 9aj: cushioning material 9b: second hole 10: opening portion 11: wire portion 12: raw water 13: aeration tank 14: Sludge 15: Aeration pipe 16: Blower 17: Pressure gauge 18: Filtration water pump 19: Flow meter 20: Filtration water 21: Filtration water tank 22: Filtration water pipe 23: Backwash water pipe 24: Backwash water pump

Claims (3)

  A cylindrical container having openings at the upper and lower ends, and at least a part of the peripheral wall is made of a porous member, and a plurality of small bundles each made of a plurality of hollow fiber membranes positioned in the vertical direction, The cylindrical container is provided at the upper end portion of the small bundle, and the small bundle is bundled and fixed integrally with the hollow portion of the hollow fiber membrane being opened, and the upper end opening portion of the cylindrical container is closed. A hollow fiber membrane fixing member fixed to the small bundle, and provided at the lower end portion of the small bundle, the hollow portion of the hollow fiber membrane is closed, and the small bundle is independently provided with an interval. A hollow fiber membrane module comprising a small bundle fixing member, wherein each of the small bundles penetrates, and a first hole having a width through which the small bundle fixing member does not penetrate, and the small bundle includes A hollow fiber comprising a pressing plate having a second hole not penetrating Module.   The hollow fiber membrane module according to claim 1, wherein at least a part of an edge of the first hole is rounded.   The hollow fiber membrane module according to claim 1, wherein at least a part of an edge of the first hole is covered with a cushioning material.

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