JP3686225B2 - Hollow fiber membrane module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention comprises a large number of hollow fiber membrane assemblies for purifying river water, well water, swamp water, lake water, etc., and for filtering liquids having high concentrations and high SS components in the process. The present invention relates to a hollow fiber membrane module to be used. The hollow fiber membrane module of the present invention is particularly effective when liquid filtration is performed by an external pressure method.
[0002]
[Prior art]
Conventionally known hollow fiber membrane filtration modules include: (1) a number of hollow fiber membranes are bent into a U shape, and both ends of the aligned hollow fiber membranes are fixed with resin. In addition, a so-called loop type in which both ends of the hollow fiber membrane are opened, and (2) one end of each of the hollow fiber membranes is fixed and opened by a resin, and the other end of each hollow fiber membrane is A so-called terminal-free type sealed one by one with resin, (3) One end of each of the hollow fiber membranes is fixed and opened with resin, and the other end of each hollow fiber membrane with resin A so-called collective seal type that is collectively sealed and fixed. (4) Both ends of the hollow fiber membrane are fixed at both ends in the longitudinal direction, and both ends are opened. There are four types of those that use up in the external pressure.
[0003]
Conventionally, in an external pressure filtration device, as a method of cleaning the hollow fiber membrane module, air is periodically sent from the lower side to the upper side in the module container, and the deposit on the membrane surface is aired by the supplied air. A method of scrubbing is known, and the function of the hollow fiber membrane is recovered by vibrating the hollow fiber membrane and removing deposits on the membrane surface (see JP-A-53-108882).
[0004]
In this film scrubbing method by air scrubbing, a shearing force is generated between the deposit adhering to the water to be treated and the water to be treated due to the film swinging. It is effective to actively swing the hollow fiber membrane. Therefore, among the four types of hollow fiber membrane modules described above, the terminal free type has the effect of separating the deposited material by air scrubbing because one end of each of the hollow fiber membranes is free to move one by one. The best.
[0005]
[Problems to be solved by the invention]
The technology for removing the deposits of the hollow fiber membrane module with air is an excellent method, but the following problems remain when a membrane cleaning method by air scrubbing is applied to a conventional hollow fiber membrane module. That is, at the time of cleaning, the hollow fiber membranes are entangled with each other along with the flow of the liquid to be treated, whereby the hollow fiber membranes are cut or stress is concentrated on one end of the hollow fiber membrane fixed with the resin. The film may be broken.
[0006]
The present invention has been made in view of the above problems, and provides a hollow fiber membrane module that does not cause breakage or breakage of the hollow fiber membrane even when a highly viscous liquid containing a high SS component is filtered. The purpose is to do.
[0007]
[Means for Solving the Problems]
The hollow fiber membrane module of the present invention that solves the above problems includes a hollow fiber membrane bundle composed of a number of hollow fiber membranes having one end sealed and the other end opened, and a container in which the hollow fiber membrane bundle is stored. And an air nozzle provided on the sealing side of the hollow fiber membrane bundle, and arranged in the vicinity of the center of the hollow fiber membrane bundle so as to extend from the sealing side of the hollow fiber membrane bundle in the longitudinal direction of the hollow fiber membrane bundle Rectifier tube.
[0008]
In the hollow fiber membrane module of the present invention, a large number of apertures may be provided in the rectifying tube so that the liquid to be treated passes through the apertures during filtration.
[0009]
In the hollow fiber membrane module of the present invention, the rectifying cylinder is located in the central region of the hollow fiber membrane bundle. Therefore, the hollow fiber membrane is cut or broken along with the flow of water to be treated, as in the case of performing membrane scrubbing by air scrubbing using a conventional hollow fiber membrane module that does not have a rectifying cylinder. Is suppressed. And since the flowability of the liquid to be treated into the hollow fiber membrane bundle is improved by the rectifying cylinder, it is difficult to exhibit the filtering ability because it is inside the hollow fiber membrane bundle and is in close contact with other hollow fiber membranes. A hollow fiber membrane can also be used effectively, and the membrane area can be substantially increased. In the filtration apparatus equipped with the hollow fiber membrane, if the filtration treatment for a predetermined time is continued, the suspended matter adheres to the membrane and the filtration efficiency is reduced. Therefore, this deposit must be removed. In particular, when there is a large amount of suspended matter, the amount of deposits increases, so frequent membrane cleaning is required, and there is a problem that water loss due to cleaning is large. If it is a hollow fiber membrane module of this invention, since the hollow fiber membrane is suppressed from being cut | disconnected or broken with the flow of to-be-processed water, the lifetime of a film | membrane can be lengthened.
[0010]
Further, if the rectifier tube is provided with a large number of apertures so that the liquid to be treated passes through the apertures during filtration by the external pressure filtration method, the liquid to be treated is directed outward from the center of the hollow fiber membrane bundle. Since it flows, the utilization efficiency of the membrane in the center portion of the hollow fiber membrane bundle can be increased.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the hollow fiber membrane module of the present invention will be described with reference to the drawings. A schematic cross-sectional view of an example of the hollow fiber membrane module of the present invention is shown in FIG. In FIG. 1, reference numeral 1 denotes a hollow fiber membrane bundle composed of a number of hollow fiber membranes, one end of the hollow fiber membrane (the figure number 2 side shown in FIG. 1) is sealed, and the other end of the hollow fiber membrane bundle (see FIG. 1). 1 is fixed with resin, and the hollow fiber membrane is opened. The hollow fiber membrane bundle 1 is stored in a container 4. The fixing member 3 converges and fixes while maintaining the open state of each end of the hollow fiber membrane of the hollow fiber membrane bundle 1, and in order to make the hollow fiber membrane function as a filtration membrane, Functions as a member that partitions the liquid so as to be liquid-tight. For the fixing member 3, a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, or polyurethane is usually used. As a bonding method between the hollow fiber membrane bundle 1 and the fixing member 3, a centrifugal bonding method, a stationary bonding method, or the like can be used. An air nozzle 5 is provided on the sealing side of the hollow fiber membrane bundle 1, and air is discharged from the air nozzle to the hollow fiber membrane bundle during membrane cleaning by air scrubbing. A fixing tool 14 for inserting the nozzle into the air introduction port may be provided in the air nozzle so that the air nozzle is accurately installed at the air introduction port also serving as a drain outlet. A rectifying tube 6 is disposed in the vicinity of the center of the hollow fiber membrane bundle 1 so as to extend from the sealing side of the hollow fiber membrane bundle 1 in the longitudinal direction of the hollow fiber membrane bundle 1, and is covered during membrane cleaning by air scrubbing. Arrange the flow of processing solution. The hollow fiber membrane module shown in FIG. 1 is used in an external pressure filtration system. In FIG. 1, 7 is a raw water inlet, 8 is a filtrate outlet, 9 is an air vent, and 10 is a drain vent. It is an air inlet, and the liquid to be treated enters from the raw water inlet 7 during filtration, is filtered by the hollow fiber membrane 1 through the outer periphery of the hollow fiber membrane bundle and the rectifier 6, and passes through the filtered water outlet 8 to the hollow fiber membrane module. I go outside. At the time of air scrubbing, the air supplied from the air introduction port 10 which also serves as a drain port is distributed by the air nozzle 5 and discharged to the hollow fiber membrane bundle 1.
[0012]
In the present invention, various hollow fiber membranes constituting the hollow fiber membrane bundle 1 can be used. For example, those made of various materials such as polysulfone, polyvinyl alcohol, polyolefin, cellulose, and PMMA can be used. There are no particular restrictions on the pore diameter, porosity, film thickness, outer diameter, etc. as long as it can be used as a filtration membrane.
[0013]
As the material of the container 4, SUS, modified PPE, polyvinyl chloride, polysulfone, polycarbonate, polyolefin, ABS resin, or the like is used. The hollow fiber membrane bundle 1 fixed by the fixing member 3, the rectifying pipe 6 and the air nozzle 5 may be bonded and fixed to the container 4 to form a so-called integrated module. Etc. may be attached to the container 4 in a liquid-tight manner. In the latter case, the hollow fiber membrane bundle 1 may be replaced and the container 4 may be used repeatedly.
[0014]
The rectifying tube 6 is a cylindrical tube extending in the longitudinal direction of the hollow fiber membrane bundle in the central region of the hollow fiber membrane bundle 1, and a small part thereof is inserted into the hollow fiber membrane bundle 1. The purpose of providing the rectifying pipe is to prevent entanglement by suppressing the movement of the hollow fiber membranes during cleaning by air scrubbing. By providing the rectifying tube, entanglement between the hollow fiber membranes can be prevented even during normal filtration use. The size, length, shape, flexibility and the like of the rectifying cylinder can be arbitrarily selected. Examples of the material of the rectifying pipe include polyethylene, polypropylene, polyvinyl chloride, polysulfone, polyester, and nylon.
[0015]
The length of the rectifying tube 6 is in the range of 1/10 to 2 times the length of the hollow fiber membrane, so that a high effect of suppressing the entanglement between the hollow fiber membranes is obtained and the membrane module is not bulky. Therefore, it is preferable. The length of the rectifying tube is more preferably in the range of 1/3 to 1.5 times the length of the hollow fiber membrane. Further, the thickness of the rectifier tube is in the range of 1/10 to 4/5 times the diameter of the hollow fiber membrane bundle, so that a high effect of suppressing the entanglement between the hollow fiber membranes is obtained, and the hollow fiber membrane membrane This is preferable for maintaining the compactness of the hollow fiber membrane module while increasing the area. The thickness of the rectifying tube is more preferably in the range of 1/5 to 1/2 times the diameter of the hollow fiber membrane bundle.
[0016]
The rectifying cylinder 6 may be provided with a large number of apertures 11 as shown in FIG. The shape of the aperture, the position of the aperture, and the number of apertures can be arbitrarily selected. By making a hole in the rectifying tube, a flow of the liquid to be treated is generated from the central portion of the hollow fiber membrane bundle to the outside, and thereby the membrane utilization efficiency at the central portion of the hollow fiber membrane bundle can be further improved. Moreover, you may provide the air nozzle which can distribute air to a rectification | straightening cylinder. By providing an air nozzle on the sealing side of the hollow fiber membrane in the rectifying tube, it is not necessary to attach an air scrubbing device to the housing, so that the structure of the membrane module can be simplified.
[0017]
A schematic cross-sectional view of a reference example of the hollow fiber membrane module of the present invention is shown in FIG. Parts having the same structure as that of the hollow fiber membrane module shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In the hollow fiber membrane module shown in FIG. 2, the rectifying pipe 6 is not provided with an opening. A schematic cross-sectional view of another example of the hollow fiber membrane module of the present invention is shown in FIG. Parts having the same structure as that of the hollow fiber membrane module shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In the hollow fiber membrane module shown in FIG. 3, the air nozzle 5 does not extend to the rectifying pipe 6 but is attached to the lower part of the container 4.
[0018]
【Example】
Hereinafter, the present invention will be described more specifically with reference to specific examples.
[0019]
EXAMPLE The following filtration experiment was conducted using the membrane module having the structure shown in FIG. Here, the hollow fiber membrane module is a vertical type, and polyvinyl alcohol having an outer diameter of 1.0 mm, an inner diameter of 0.6 mm, and an average pore diameter of 0.02 μm is placed in a container having an inner diameter of 187 mm and a length of 1060 mm. 10,000 coated polysulfone membranes are filled (total membrane area is 30 m ² ). The rectifying pipe is a pipe made of polyvinyl chloride, and an outer diameter of 68 mm and a length of 980 mm are bonded and fixed to the fixing member. The rectifying cylinder is provided with openings having a diameter of 10 mm so as to have an interval of 100 mm. Using this hollow fiber membrane module, river water (turbidity 1 to 10) that has not been pretreated is subjected to membrane cleaning by air scrubbing at a frequency of once every 30 minutes for 6 months. Followed by filtration. The increase in transmembrane pressure difference (ΔP) during this period was measured and found to be 100 kPa.
[0020]
Comparative Example River water was filtered under the same conditions using a membrane module having the same structure as that used in the example except that there was no rectifying pipe. When the rate of increase of the pressure relative to the initial transmembrane pressure was measured, the transmembrane pressure (ΔP) increased to 300 kPa in one month, and the test was abandoned. Moreover, the free end side of the hollow fiber membrane of the membrane module was entangled, and many deposits were observed on the membrane surface.
[0021]
As is clear from this test result, the hollow fiber membrane module of the present invention has an excellent cleaning effect, and in the comparative example, entanglement of the free end of the hollow fiber membrane was observed, but in the examples, it was intact. Met.
[0022]
【The invention's effect】
According to the hollow fiber membrane module of the present invention, the hollow fiber membrane is not cut or broken, and stable filtration over a long period of time is possible.
[Brief description of the drawings]
FIG. 1 is a schematic structural diagram of an example of a membrane module of the present invention.
FIG. 2 is a schematic structural diagram of a reference example of the membrane module of the present invention.
FIG. 3 is a schematic structural diagram of another example of the membrane module of the present invention.

Claims (1)

A hollow fiber membrane bundle comprising a large number of hollow fiber membranes sealed at one end and opened at the other end, a container for storing the hollow fiber membrane bundle, and an air provided on the sealing side of the hollow fiber membrane bundle An inlet, and a rectifying tube disposed in the vicinity of the center of the hollow fiber membrane bundle so as to extend in the longitudinal direction of the hollow fiber membrane bundle from the sealing side of the hollow fiber membrane bundle . A hollow fiber membrane module provided with an opening, and configured such that a liquid to be treated passes through the opening during filtration .

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