JPS60255115A - Hollow fiber filtration module - Google Patents

Abstract

PURPOSE:To obtain the titled hollow yarn filter module with high availability of hollow yarn filter membranes and suitable for purifying water contg. metallic ions and colloidal materials in large quantities by regulating the ratio of the cross-sectional area occupied by the hollow yarn filter membranes to the inner cross-sectional area of an annular member within a specified range when the module is cut in the vertical direction. CONSTITUTION:The setting density of hollow yarn filter membranes 3 which are fixed at the inner surface of an annular member 1 by a fixing member 2, namely, the ratio R of the sum Sf of the cross-sectional areas of the hollow yarn filter membranes 3 to the inner cross-sectional area Sr of the annular member 1 when the annular member 1 is cut in the direction vertical to the hollow yarn filter member 3 is regulated to satisfy 0.11<=R=Sf/Sr<=0.60. Accordingly, the liquid flows easily to the central part of the aggregate of the hollow yarn filter membranes, and the availability of the whole filter membranes can be increased. When the membrane is regenerated by bubbles, bubbles are able to penetrate into the central part of the bundle of filter membranes, and the function can be sufficiently restored.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a hollow fiber filtration module for a water purifier, and more specifically, the present invention relates to a hollow fiber filtration module for a water purifier. The present invention relates to a hollow fiber filtration module suitable for use in water purifiers for purifying large amounts of water.

[Prior art] Water purifiers that use ultrafiltration filters are typically known for removing iron rust and suspended matter in water, but the filters tend to become clogged. . Furthermore, there is a limit to the size of fine particles that can be removed by such water purifiers, and metal ions cannot be removed.

For example, recovered water recovered from boiling water nuclear power generation turbines contains impurities such as about 15 Pppb of iron ions and fine colloids, but this is recovered as is and recycled as condensate to the reactor. If this occurs, the impurities will coagulate and adhere in the furnace, leading to a decrease in power generation efficiency. Therefore, it is necessary to purify and condense S so that the amount of these impurities is at least about 0.5 PPb or less.

As mentioned above, when it is necessary to remove extremely fine colloidal substances, metal ions, etc., which are impurities contained in recovered water, with high efficiency, reverse osmosis membranes are used in the general water treatment field. The water purification device used is being used suitably. However, in the case of reverse osmosis membrane equipment, the pressure required for filtration tends to be very high, so the equipment needs to be large, and systems that need to be closed systems, such as the treatment of water recovered from nuclear power generation, are required. It was unsuitable for use as a filtration module.

On the other hand, porous hollow fiber filtration membranes have an excellent water purification function, but they have been applied to fields where it is necessary to filter a large amount of water that contains relatively large amounts of fine colloidal substances and metal ions. At present, it has not been used much in the past because of the problem that the filtration membrane is easily clogged and it is difficult to eliminate the clog and restore the function.

Furthermore, in the case of treating nuclear power generation circulating water, no practical filtration device has been developed not only from a functional standpoint, but also from the economical, maintenance and management, and waste disposal standpoints.

As a method to easily restore the filtration function while the hollow fiber filtration module is installed in the purification device, the water flow is reversed to that during filtration, and at the same time, air bubbles are applied to the hollow fiber filtration membrane from below to remove the hollow fiber filtration. A method has been developed in which physical vibration is applied to the thread filtration membrane to shake off colloidal substances that have aggregated and stuck to the surface of the hollow fiber filtration membrane. Its use is being considered and is being put into practical use. With this practical application, it is necessary to increase the size of the hollow fiber filtration module in order to treat a large amount of water with a predetermined installation volume. Increasing the size of a hollow fiber filtration module is generally done by packing as many hollow fiber filtration membranes as possible into a given volume. It is difficult for the liquid to flow to the center of the filtration membrane assembly, and conversely, when the liquid to be treated flows from the inside of the hollow fibers to the outside, it becomes difficult for the liquid to flow through the hollow fibers to the outside of the hollow fiber filtration membrane assembly, and eventually Also in this case, as a result, the entire hollow fiber filtration membrane forming the aggregate cannot be used effectively. Also, when performing the above-mentioned regeneration process using air bubbles, it may be because the air bubbles do not easily hit the surfaces of the individual hollow fiber filtration membranes that form the aggregate.
It has been found that the above-mentioned regeneration treatment method cannot restore the function of the hollow fiber filtration membrane sufficiently.

The present inventors continued to study these problems, and as a result, the effective use of hollow fiber filtration membranes and the recovery of the filtration function were determined.
The inventors discovered that there is a strong correlation with the installation density of hollow fiber filtration membranes within the fixed member, and discovered that a hollow fiber filtration module with a specific configuration has excellent filtration function recovery properties, leading to the completion of the present invention. .

[Objective of the Invention 1 The object of the present invention is to provide a hollow fiber filtration membrane for a water purifier suitable for treating a large amount of water containing relatively large amounts of metal ions and extremely fine colloidal substances. be.

Another object of the present invention is to provide a hollow fiber filtration module suitable for increasing the utilization efficiency of hollow fiber filtration membranes.

Still another object of the present invention is to provide a hollow fiber filtration module that can easily perform a cleaning operation to restore filtration function while being installed in a purification device.

[Structure of the Invention] That is, the hollow fiber filtration module of the present invention includes an annular member and a large number of hollow fiber filtration membranes fixed to the inner surface of the annular member in a U-shape with each open convex end kept open. In a hollow fiber filtration module equipped with a fixed member that is focused and fixed on a mold, the occupied cross-sectional area of the hollow fiber filtration membrane (Sf) when the annular member is cut in a direction perpendicular to the hollow fiber filtration membrane
The ratio R of the internal cross-sectional area of the annular member (Sr) satisfies the following: 0, 11≦R=Sf/Sr≦0.60.

[PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION] Hereinafter, the hollow fiber filtration module of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the hollow fiber filtration module of the present invention, FIG. 1a is a perspective view thereof (illustration of the hollow fiber filtration membrane is omitted), and FIG. 1b is a - It is a sectional view cut along the A line. FIG. 2 is a schematic perspective view showing another embodiment.

The hollow fiber filtration module of the present invention basically comprises an annular member 1, a fixing member 2, and a hollow fiber filtration membrane 3,
A support member 4, hollow fiber support member 5, etc. may be attached as desired.

The annular member l functions as a support member for supporting the entire hollow fiber filtration module when it is installed in a water purifier, and typically has a ring shape, but may have a cross section such as a rectangle. It may be of any shape. Further, the shape of the outer peripheral surface thereof can take various shapes depending on the manner in which the module is installed in the water purifier. A fixing member 2 is joined to the inner surface of this annular member l, which serves as a partition member between the water to be purified and the purified water in order to fix the hollow fiber filtration membrane 3 and make it function as a filtration membrane. Ru. A large number of hollow fiber filtration membranes 3 are fixed to the fixing member 2 in a U-shaped bundle with their open ends kept open. The fixing member 2 is generally made of polyurethane, polyester, epoxy resin, or the like.

In the hollow fiber filtration module of the present invention, the fixing member 2
The installation density of the hollow fiber filtration membrane 3 fixed by The ratio R of the sum (SF) of the cross-sectional area (including the hollow portion) of all the hollow fiber filtration membranes 2 and the internal cross-sectional area (Sr) of the annular member 1 is 0.11≦R=Sf/Sr≦0. 60.

If the installation density (R) of the hollow fiber filtration membranes is too high, it will be difficult for the hollow fiber filtration module to take a form in which all the gaps between the hollow fiber filtration membranes are filled with fixing members, and the partitions Since it will no longer function as a member, R
The value of has a limit. However, in a relatively large hollow fiber filtration module, even if the installation density of the hollow fiber filtration membrane is such that the fixed member can sufficiently function as a partition member, if R exceeds 0.60, the hollow fiber filtration membrane The installation density of the fiber filtration membranes is too high, and when the liquid to be treated flows from the outside to the inside of the hollow fibers, it is difficult for the liquid to flow to the center of the hollow fiber filtration membrane assembly, and when it flows from the inside to the outside, the liquid does not flow to the center of the assembly. The liquid passing through the hollow fibers located in the center becomes difficult to flow out of the hollow fiber filtration membrane assembly, and in either case, as a result, the utilization efficiency of the hollow fiber filtration membrane located in the center of the assembly decreases. Furthermore, since the bubbles cannot enter the center of the hollow fiber filtration membrane assembly during the bubble treatment, only the outer surface layer of the hollow fiber filtration membrane assembly can be treated for functional recovery. This phenomenon is caused by the internal cross-sectional area (Sr) being l0CI11
This is particularly noticeable in two or more large-sized hollow fiber filtration modules. If the internal cross-sectional area (Sr) is 30 cm2 or more,
More preferably, R is 0.5 or less.

Conversely, if R is small, the above problem does not occur, but R
If it is too small, such as less than 0.11, the amount of water to be treated per unit hollow fiber filtration module will be reduced, which is not practical as it goes against the requirement of making the module more compact. It is desirable that R is 0.2 or more, more preferably 0.3 or more.

In the hollow fiber filtration module of the present invention, as shown in FIG. A support member 4 is joined to the annular member l, and this support member 4
A hollow fiber support member 5 passes through the center of the U-shaped portion of the hollow fiber filtration membrane 3 (see FIG. 1b) at the tip or midway of the hollow fiber filtration membrane 3 to maintain the U-shape of the hollow fiber filtration membrane 3 at all times. may be joined.

In the example of FIG. 1, the support member 4 is installed in the form of two pillars, each of which remains substantially parallel to the other, but in FIG. It is configured as a cylindrical member provided with an opening 6, and is installed so as to cover the U-shaped portion of the hollow fiber filtration membrane 3.

The cylindrical support member 4 protects the hollow fiber filtration membrane 3 from being damaged during storage or transportation from the time the hollow fiber filtration module is manufactured until it is actually used.

The hollow fiber support member 5 in FIG. 1 may cause the hollow fiber filtration membranes 3 to float up due to the water flow during filtration, or the U-shaped bundled shape of the hollow fiber filtration membranes 3 to be disturbed during the bubble regeneration process, and the hollow fiber filtration membranes 3 to be attached to each other. Entanglement may occur, creating a large filtration resistance to the water flow during subsequent filtration, or in extreme cases, this entanglement may damage a part of the hollow fiber filtration membrane 3, making it no longer able to function as a filtration membrane. The role is to prevent such situations from occurring. In addition, hollow fiber filtration membrane 3
Since the U-shaped focused shape of is maintained, the air bubbles can be more uniformly applied to the hollow fiber filtration membrane 3, and the function recovery process of the hollow fiber filtration membrane 3 by the above-mentioned air bubble treatment method can be carried out more smoothly. make it possible. Furthermore, in addition to the above, the hollow fiber support member 5 also serves to prevent the hollow fiber filtration membrane 3 from being subjected to excessive bending fatigue and premature deterioration. Therefore, adding such a hollow fiber support member 5 is a more preferable embodiment of the present invention.

The opening 6 provided on the cylindrical support member 4 in FIG.
It plays the role of discharging air bubbles to the outside of the hollow fiber filtration module during the air bubble regeneration process. If this opening 6 is made larger, hollow fiber filtration can be carried out during the swindling process or bubble regeneration process! It is also possible to increase the degree of freedom of movement of I3 and improve the contact efficiency between the hollow fiber filtration membrane 3 and the water to be purified.

The annular member as a member constituting the hollow fiber filtration module of the present invention, the support member attached as desired, the hollow fiber support member, etc. are all hydrocarbon-based materials that can be completely combusted by incineration without emitting harmful gases. It is preferable that the material is made of resin. In addition, hollow fiber filtration membrane 3
Various materials can be used as the filter, such as hollow fiber filtration membranes made of various materials such as cellulose, polyolefin, polysulfone, polyvinyl alcohol, and PMMA. However, polyolefin-based porous hollow fibers H are known as those having excellent durability and excellent filtration performance. Among these, the micropores of the membrane are suitable for filtering fine colloidal substances1, and the membrane can withstand external forces applied during backwashing, which is usually used as a function recovery operation for clogging of the filtration membrane. Membranes are particularly preferably used, and examples of such hollow fiber membranes include:

For example, polyethylene hollow fiber # (polyethylene hollow fiber EH
F, trade name, manufactured by Mitsubishi Rayon ■).

[Effects of the present invention] As described above, according to the hollow fiber filtration module of the present invention configured such that the installation density of the hollow fiber filtration membranes in the annular member is below a predetermined value, the liquid to be treated is filtered through the hollow fibers. When flowing from the outside to the inside, the liquid easily flows to the center of the hollow fiber filtration membrane assembly, and when flowing from the inside to the outside, the liquid that has passed through the hollow fibers located at the center of the assembly also flows into the hollow fiber filtration membrane assembly. It becomes easier to flow out of the body, and as a result, the utilization efficiency of the hollow fiber filtration membrane of the entire assembly is improved. Furthermore, during the regeneration process of the hollow fiber filtration module due to air bubbles, the air bubbles can enter the center of the bundle of hollow fiber filtration membranes, so the function recovery process of the filtration membranes can be performed while the air bubbles are installed in the purification device using the air@isolation method. It can be implemented smoothly. Therefore, the entire bundle of hollow fiber filtration membranes can function as a filtration membrane for a long period of time, and it is possible to exhibit excellent performance as a hollow fiber filtration module for a water purifier on an industrial scale.

Examples 1 to 4, Comparative Example 1.2 Two supporting members each having a length of 740 mm, a width of 20 mm, and a thickness of 5+ sm are joined to an annular member having an inner diameter of 85+s+*φ and a height of 70IllI, and the An 8-■φ hollow fiber support member was attached to the lower part to form a support for a hollow fiber filtration module as shown in FIG. A bundle of polyethylene hollow fibers EHF (hollow fiber-wood cross-sectional area: 0.118+s+w2) was bundled into a U-shape on this support via a hollow fiber support member. Next, a hollow fiber filtration membrane module was created using polyurethane resin as a fixing member. The length of the zero-shaped portion of one hollow fiber filtration membrane extending from the fixing member to the fixing member was about 140 hm on average. Hollow fiber filtration modules were manufactured in which the number of hollow fibers used was varied as shown in Table 1, and the installation density R of the hollow fiber filtration membranes was varied.

Using these hollow fiber filtration modules separately,
Approximately 10% of iron ions and fine colloidal substances (8μ in particle size)
Concerning water containing a concentration of ppm, purification treatment was carried out continuously for 15 days so that the amount of water treated per unit surface area of the hollow fiber filtration membrane was approximately constant. After this, the bubble regeneration process described above was carried out for 1 hour. In the purification process, all hollow fiber filtration modules were able to purify the concentration of impurities such as iron ions to less than 0.5 PPb, but depending on the hollow fiber filtration module used, A difference occurred in the processing pressure as shown in the table.

Further, FIG. 3 shows a graph of the change in differential pressure over time for each hollow fiber filtration module.

Examples 5 to 7, Comparative Example 3.4 Table 1 shows the number of hollow fibers in an annular member having the same dimensions as in Example 1 except that no support member and hollow fiber support member were provided. Five types of hollow fiber filtration modules were manufactured by making various changes as shown below, and varying the installation density R of the hollow fiber filtration membranes. The same test as in Example 1 was conducted on these hollow fiber filtration modules. The results are also shown in Table 1.

Examples 8 to 11, Comparative Example 5 Using an annular member with an inner diameter of 65 mmφ and a high tension of 70 mm+, the U of a single hollow fiber filtration membrane from the fixed member to the fixed member is used.
A hollow fiber filtration module was manufactured in the same manner as in Example 1 except that the average length of the character portion was approximately 2oooIII11. The number of hollow fibers in each hollow fiber filtration module was changed to five types as shown in Table 1, and the installation density R was changed.

The same test as in Example 1 was also conducted on these hollow fiber filtration modules. The results are also shown in Table 1.

6

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the hollow fiber filtration module of the present invention, FIG. 1a is a perspective view thereof (illustration of the hollow fiber filtration membrane is omitted), and FIG. It is an A-line sectional view. FIG. 2 is a schematic sectional view showing another embodiment, but illustration of the hollow fiber filtration membrane is omitted in this figure as well. FIG. 3 is a graph showing changes in differential pressure over time for each hollow fiber filtration module. 1: Annular member 2: Fixed member 3: Hollow fiber filtration membrane 4: Support member 5: Hollow fiber support member 6: Opening 9

Claims (1)

[Scope of Claims] l) An annular member and a fixing member that is fixed to the inner surface of the annular member and that collects and fixes a large number of hollow fiber filtration membranes in a U-shape while keeping their respective open ends open. In the hollow fiber filtration module provided, the occupied cross-sectional area (sr) of the hollow fiber filtration membrane and the internal cross-sectional area (Sr) of the annular member when the annular member is cut in a direction perpendicular to the hollow fiber filtration membrane are A hollow fiber filtration module characterized in that the ratio R satisfies 0.11≦R=Sf/Sr≦0.60. 2) The hollow fiber filtration module J according to claim 1, wherein the annular member has an internal cross-sectional area (Sr) of 10 cm2 or more.
death.