JPS624408A - Filtration device using hollow yarn membrane - Google Patents

Abstract

PURPOSE:To enable uniform supply of bubbles to a whole body of a hollow yarn membrane filter by providing a short bubbling pipe having second foam pores to above a mother bubbling pipe, and effectively conducting bubbling by feeding foams also to a hollow yarn membrane filter just above the bubbling mother pipe. CONSTITUTION:A short bubbling pipe 121 is inserted and fixed from above a mother pipe 112 in a bubbling device 111 comprising a mother bubbling pipe 112 and plural branched bubbling pipe 113 branched therefrom, and a top end of the short pipes 121 is closed with a cover body 123 to form plural second foam pores 122 below the closed part. A foot end of the short pipe 121 is opened and extended to the same level position as first foam pores 114 formed in the branch pipe 113. When the hollow yarn membrane filter 2 is to be backwashed, a part of the air fed to the mother pipe 112 is fed to a filter 2 just above the mother pipe 112 through the second foam pores 122 of the short pipe 121 in the form of foam, and solid product formed on the surface of the filter 2 is effectively peeled by simultaneously feeding the air from first foam pores 114 of the branch pipe 113 as conventionally performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a hollow fiber membrane filtration device capable of uniformly and effectively bubbling the entire device.

[Technical Background of the Invention] In general, in nuclear power plants, the generation of corrosion products is suppressed and removed as radiation reduction measures. For example, filtration devices are used to separate and remove suspended matter present in radioactive waste liquid generated in nuclear power plants or in condensate water of primary cooling systems. As for this filtration device, there are conventional methods using pre-coated filters such as powdered ion exchange resin, methods using flat membrane filters such as filter paper and filter cloth membrane filters, and methods such as sintered metals, ceramics, etc. There is a method using a hollow tube filter.

However, filtration methods that use powdered ion exchange resin generate a large amount of resin waste, and those that use flat membrane filters or hollow tube filters require a large circulation flow rate, resulting in a complicated configuration. Therefore, there was a problem in that equipment costs increased accordingly. Not only that, but it also generated secondary waste and had low filtration efficiency.

In order to solve this problem, a hollow fiber membrane filtration device using a hollow fiber membrane filter has been adopted. A conventional hollow fiber membrane filtration device will be described below with reference to FIGS. 8 to 10. Reference number 1 in FIG. 8 is a container body, and a plurality of hollow fiber membrane filters 2 are installed in this container body 1 with partition plates 3 interposed therebetween. The hollow fiber membrane filter 2 is made by bundling a plurality of hollow fibers 2A into a U-shape, the ends of which are fixed with resin, and is attached to the partition plate 3 via this fixing part. A waste liquid supply pipe 4 is connected to an approximately intermediate position in the axial direction of the container body 1, and a processing liquid discharge pipe 5 is connected to the upper end thereof.

The waste liquid supplied through the waste liquid supply pipe 4 is filtered when passing through the hollow fiber membrane filter 2, and is filtered through each hollow fiber 2A.
It flows out above the partition plate 3 through the hollow part and is discharged through the processing liquid discharge pipe 5. Note that on-off valves 6 and 7 are inserted into the waste liquid supply pipe 4 and the treated liquid discharge pipe 5. A gas supply pipe 8 is branched and connected to the processing liquid discharge pipe 5 . Pressurized gas for backwashing is supplied to the hollow portion of each hollow fiber 2A of the hollow fiber membrane filter 2 through this gas supply pipe 8. Note that the reference numeral 9 in the figure is an on-off valve.

A bubbling device 11 is installed within the container body 1 and below the hollow fiber membrane filter 2 . The configuration of this bubbling device 11 will be explained below. Symbols in the diagram・
12 is a bubbling main pipe, and this bubbling main pipe 1
A bubbling branch pipe 13 branches off from 2. A bubble hole 14 is formed on the lower surface side of the bubbling branch pipe 13. The bubbling main pipe is connected to an air supply pipe 15. Note that the reference numeral 16 in the figure is an on-off valve. Bubbles are generated by the bubbling device 11 having such a configuration, and the hollow fiber membrane filter 2 is bubbled (vibrated) by the bubbles.
This increases cleaning efficiency during backwashing. that time,
A protection tube 17 is installed around the outer periphery of the hollow fiber membrane filter 2 in order to efficiently introduce the generated air bubbles into the vicinity of the hollow fiber membrane filter 2.

A concentrated waste liquid discharge pipe 18 for discharging concentrated waste liquid after discharging the processing liquid is connected to the lower end outlet of the container body 1, and an on-off valve 19 is inserted into this concentrated liquid waste liquid pipe 18. ing. Further, an overflow pipe 20 is connected below the mounting position of the partition plate 3. An on-off valve 21 is inserted into this overflow pipe 20.

According to the above configuration, waste liquid is first introduced into the container body 1 via the waste liquid supply pipe 4 at a constant pressure. As described above, the introduced waste liquid is filtered when passing through the hollow fiber membrane filter 2 to become a treatment liquid, and flows out above the partition plate 3 through the hollow portion of the hollow fibers 2A. The processing liquid is then discharged via the processing liquid discharge pipe 5.

Thereafter, pressurized gas is supplied from the gas supply pipe 8 to each hollow portion of the hollow fiber 2A. As a result, suspended matter adhering to the outer periphery of the hollow fiber 2A is removed.

At the same time, bubbles are generated by the bubbling device 11 and introduced into the hollow fiber membrane filter 2 via the protective tube 17. This causes the hollow fiber membrane filter 2 to vibrate, thereby improving the solid matter removal effect.

After the concentrated waste liquid is discharged, the waste liquid is supplied again via the waste liquid supply pipe 4. Then, filtration and backwashing are repeated by the same action as described above.

[Problems with background technology] According to the two-leg configuration, there were the following problems.

In the hollow fiber membrane filtration device, the arrangement of each device is determined in order to make the size of the container body 1 as compact as possible. 1st
Figure 0 is a cross-sectional view of the hollow fiber membrane filtration device, and this 1st θ
As is clear from the figure, the hollow fiber membrane filters 2 are densely arranged. Further, below the hollow fiber membrane filter 2, the above-mentioned bubbling device 1 unit is installed. As shown in the figure, the hollow fiber membrane filter 2 is also located directly above the bubbling main tube 12 of the bipedal bubbling device 11. However, unlike the bubbling branch pipe 13, the bubbling main pipe 12 does not have bubble holes formed in its lower part. This is because the bubbling main tube 11 is formed to have a relatively large diameter, and if bubble holes were formed at the bottom, the bubbles would be dispersed, and most of the bubbles would flow out from the bubble holes of the main tube 12. This is to prevent air bubbles from being sufficiently generated from the branch pipe 13. Therefore, there is a problem in that the hollow fiber membrane filter 2 located directly above the bubbling main tube 12 is not bubbling effectively, and an improvement has been required.

[Object of the Invention] The present invention has been made based on the above points, and its purpose is to uniformly supply air bubbles to a hollow fiber membrane filter, thereby uniformly improving the solid matter removal effect. The object of the present invention is to provide a hollow fiber membrane filtration device that is possible.

[Summary of the Invention] That is, the hollow fiber membrane filtration device according to the present invention includes a plurality of hollow fiber membrane filters installed in a container main body, and waste liquid is introduced into the container main body and filtered by passing through the hollow fiber membrane filter. The hollow fiber membrane filtration device includes a bubbling main tube disposed within the container body below the hollow fiber membrane filter, and a plurality of first bubble holes branched from the bubbling main tube on the lower surface side thereof. a bubbling branch pipe, and a bubbling short pipe which is inserted and fixed into the bubbling main pipe from the -L direction, has its lower end opening on the same level as the first bubble hole, has its -1 end closed, and has a second bubble hole in the upper part. It is characterized by comprising a pipe.

In other words, a short bubbling pipe is installed above the bubbling main pipe, and bubbles are supplied from the second bubble hole formed in this short bubbling pipe to the hollow fiber membrane filter located directly above the bubbling main pipe, and this is effectively bubbling. At this time, the bubbling short pipe has its lower end opening extended to the same level as the first bubble hole formed in the bubbling branch pipe, and its upper end is closed. This effectively prevents the intrusion of air bubbles and the clogging of air bubble pores.

[Embodiment of the Invention] A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3. Note that parts that are the same as those in the prior art are denoted by the same reference numerals, and their explanations will be omitted. Reference numeral 111 in the figure indicates a bubbling device according to this embodiment. The bubbling device 111 includes a bubbling main pipe 112 and a plurality of bubbling branch pipes 113 branched from the bubbling main pipe 112. The positional relationship between the bubbling main pipe 112 and the bubbling branch pipe 113 is as shown in the cross-sectional view of FIG. 3. At the bottom of the bubbling branch pipe 113 is a bubble hole←
A plurality of →→114 are formed at equal intervals. That is, the air supplied into the bubbling main pipe 112 via the air supply piping 15 flows through the bubble holes 11 of the bubbling branch pipe 113.
4 and is supplied to the hollow fiber membrane filter 2 via a protective tube 17.

A bubbling short tube 121 is inserted and fixed into the bubbling main tube 112 from above. This bubbling short pipe 12
1 is closed by a lid 123, and a plurality of second bubble holes 122 are formed below the closed portion. Further, the lid body 123 is larger than the outer shape of the bubbling short tube 121. The lower end of the bubbling short pipe 121 is open and extends to the same level as the first bubble hole 114 formed in the bubbling branch pipe 113. Therefore, a part of the air supplied into the bubbling main pipe 112 is transferred to the second bubble hole 122 of the bubbling short pipe 121.
flows out through. With this configuration, air bubbles are effectively supplied to the hollow fiber membrane filter 2, which is located directly above the bubbling main tube 112 and where bubbling has not been performed effectively, and bubbling is performed. It is the composition.

The operation will be explained based on the above configuration. First, the waste liquid supplied into the container body 1 via the waste liquid supply pipe 4 permeates inside each hollow fiber 2A of the hollow fiber membrane filter 2, and is filtered at that time. The filtered processing liquid flows out above the partition plate 3 through the hollow portion of the hollow fiber 2A, and is further discharged via the processing liquid discharge pipe 5. Filtration is performed through this route.

Then, the waste liquid is supplied into the container body 1 through the waste liquid supply piping 4.
The supply is continued at a constant pressure, and filtration is continued until the filtration differential pressure of the hollow fiber membrane filter 2 reaches a preset value. When the predetermined filtration pressure is reached, the filtration operation is stopped and the hollow fiber membrane filter 2 is backwashed. This backwashing is performed by the reverse route to the above filtration. That is, water or air is pressure-fed into the hollow fiber membrane filter 2 via the gas supply piping 8 from a gas supply source (not shown). Solid matter adhering to the outer surface of the hollow fiber membrane filter 2 is removed by such pressure feeding of water or air. At this time, bubbles are generated from the micropores formed on the outside of the hollow fiber membrane filter 2, so
Backwashing effect is enhanced. In addition, a bubbling operation by the bubbling device 111 is performed in synchronization with such backwashing operation.

That is, the bubbling main pipe 1 is connected via the air supply pipe 15.
Air is supplied into 12. A portion of the supplied air is supplied as bubbles through the second bubble hole 122 of the bubbling short pipe 121 toward the hollow fiber membrane filter 2 located directly above the bubbling main pipe 112 . At the same time, the air supplied into the bubbling branch pipe 113 is supplied to the upper hollow fiber membrane filter 2 via the first bubble hole 114 as in the conventional manner. At this time, the second bubble hole 122 formed in the bubbling short pipe 121 is formed on the side surface of the bubbling short pipe 121, so that the solid matter separated from the hollow fiber membrane filter 2 flows into the bubbling main pipe 112. Not at all. Furthermore, since the lower end of the short bubbling pipe 121 extends to the same level as the first bubble hole 114 of the bubbling branch pipe 113, the conditions for bubbles to flow out are approximately the same, and the bubbles flow out intensively from the short bubbling pipe 121. There's nothing to do. In this way, bubbling by the bubbling device 111 is performed, and together with the backwashing action, solid matter is effectively peeled off from the surface of the hollow fiber membrane filter 2. By such backwashing operation, the hollow fiber membrane filter 2 is regenerated and used for the next filtration, and the same filtration action as described above is repeated again.

According to this embodiment, the following effects can be achieved.

(1) First, bubbles were generated only from the bubbling branch pipe 113 in the past, but in the case of this embodiment, bubbles were generated from the second bubbling short pipe 121 attached to the bubbling main pipe 112.
Since the structure is such that bubbles are also generated from the bubble holes 122, it is possible to effectively perform bubbling even for the hollow fiber membrane filter 2 located directly above the bubbling main pipe 112, which was previously unable to perform an effective bubbling operation. becomes. As a result, solid matter is removed uniformly and effectively from all hollow fiber membrane filters 2 during backwashing, and the hollow fiber membrane filters 2 can be effectively regenerated.

(2) Next, the bubbling short pipe 121 according to this embodiment has its lower end extended to the same level as the bubble hole 114 of the bubbling branch pipe 113, so that the conditions for bubble generation are approximately equal. Therefore, it is possible to prevent bubbles from being generated intensively from any of the bubble holes, and to supply bubbles uniformly.
By making the sizes of 14 and 122 appropriate, it is possible to make the size and amount of bubbles uniform.ii
It becomes f-ability.

(3) Furthermore, the second bubble hole 122 of the bubbling short pipe 121 according to this embodiment is formed on the side surface of the bubbling short pipe 121, and the lid body 123 that closes the upper end opening has a diameter of the bubbling short pipe 121. Since the diameter is larger, exfoliated solid matter and the like will not enter the bubbling short tube 121, and the second bubble hole 122 can be prevented from being clogged.

Next, a second embodiment will be described with reference to FIGS. 4 to 7. The above example shows an example in which a so-called U-shaped hollow fiber membrane filter was implemented, but this example! This figure shows a case where a type of hollow fiber membrane filter is applied. Generally, in order to increase the filtration flow rate, the surface area of the hollow fibers is increased, and specifically, the use of longer hollow fiber membrane filters can be considered. However, since the inner diameter of each hollow fiber is very small, about 0.3 mm, the fluid resistance when flowing through the hollow portion is large, and therefore there is a limit to the length of the hollow fiber membrane filter.

Therefore, the above-mentioned L-type hollow fiber membrane filter was devised.

The above-mentioned I-type hollow fiber membrane filter is constructed as shown in FIG.
133. Further, a water collection pipe 133 is arranged in the center thereof.

As shown in FIG. 5, these structures are connected in the axial direction, thereby increasing the surface area. Note that the reference numeral 134 in the figure is a connector. The waste liquid then permeates into the interior of each hollow fiber and is filtered at this time. The permeated waste liquid (filtered into a treated liquid) flows upward or downward inside the hollow fibers, and flows through the water collecting pipe 133 or directly above the partition plate 3. The subsequent steps are the same as in the first embodiment.

An embodiment in which the present invention is applied to an I-type hollow fiber membrane filter 2 having the above structure is shown in FIGS. 6 and 7. Note that the reference numeral 141 in the figure is a lower lid body. Note that bubbling device 111
The structure and operation of the second embodiment are the same as those of the first embodiment, and the explanation thereof will be omitted.

E-1 According to the second embodiment, it is possible to achieve the same effects as the first embodiment, but especially in the case of a filtration device with a large flow rate, the bubbling mother inevitably occurs. Since the diameter of the tube 112 becomes larger and the number of hollow fiber membrane filters 2 located above the bubbling main tube 112 increases accordingly, it can be said that this is extremely effective.

[Effects of the Invention] As detailed above, according to the hollow fiber membrane filtration device of the present invention, air bubbles can be effectively supplied to the hollow fiber membrane filter located directly above the bubbling main pipe to perform pub linking. Furthermore, it is possible to supply bubbles uniformly throughout the entire filter, which is extremely effective in regenerating the hollow fiber membrane filter.

[Brief explanation of drawings]

1 to 3 are diagrams showing a first embodiment of the present invention,
Fig. 1 is a sectional view of the hollow fiber membrane filtration device 1, Fig. 2 is a sectional view showing a part of Fig. 1 in detail, Fig. 3 is a cross-sectional view of the hollow fiber II membrane filtration device, and Figs. Fig. 7 is a diagram showing the second embodiment, Fig. 4 is a sectional view of the I-type hollow fiber membrane filtration device, Fig. 5 is a sectional view showing the state where the ■-type hollow fiber membrane filter is connected, and Fig. 6 is a sectional view of the I-type hollow fiber membrane filtration device. A sectional view of a hollow fiber membrane filtration device, FIG. 7 is a sectional view showing a part of FIG. 6 in detail, FIGS. 8 to 10 are views showing conventional examples, and FIG. 8 is a hollow fiber membrane filtration device. 9 is a sectional view showing a part of FIG. 8 in detail, and FIG. 10 is a cross-sectional view of the hollow fiber membrane filtration device. 1... Container body, 2... Hollow fiber membrane filter, 111
...bubbling device, 112...bubbling main pipe,
113... Bubbling branch pipe, 114... First bubble hole, 121... Bubbling short tube, 122... Second bubble hole, 123... Lid body. Applicant's representative Patent attorney Takehiko Suzue Figure 2 Figure 3 Figure 4 Figure 5 Figure 7

Claims (2)

[Claims] (1) Install multiple hollow fiber membrane filters inside the container body,
In a hollow fiber membrane filtration device that introduces waste liquid into the container body and filters it by passing through the hollow fiber membrane filter, a bubbling main tube disposed within the container body and below the hollow fiber membrane filter; , a buffing branch pipe which is branched from the bubbling main pipe and has a plurality of first bubble holes on its lower surface side; and a buffing branch pipe which is inserted and fixed into the bubbling main pipe from above and whose lower end opening is on the same level as the first bubble holes and whose lower end opening is on the same level as the first bubble holes. 1. A hollow fiber membrane filtration device comprising: a bubbling short tube whose upper end is closed and which has a second bubble hole in the upper portion. (2) The hollow fiber according to claim 1, wherein the short bubbling tube has its upper end closed by a lid, and the lid is formed to have a larger outer diameter than the short bubbling tube. Membrane filtration device.