JP2693070B2 - Hollow fiber membrane filtration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane filtering apparatus suitable for filtering radioactive waste liquid, condensate water, etc. in a nuclear power plant, and more particularly to a protective tube for protecting the outer periphery of a hollow fiber membrane module. The present invention relates to a hollow fiber membrane filtration device having an improved support method.

[0002]

2. Description of the Related Art Generally, in a nuclear power plant,
As a measure to reduce radiation, we are suppressing the generation of corrosion products and removing them.For example, a filtering device is used to separate and remove radioactive waste liquid or suspensions that are present in the condensate of the reactor condensate feedwater system. There is.

As the filtering device, a filtering device using a pre-coated filter such as a powder ion exchange resin, a flat-film type filtering filter such as a filter paper, a filter cloth, a membrane filter, etc., a sintered metal, a ceramic, etc. have been conventionally used. Although an empty tube type filter is used, in recent years, a hollow fiber membrane filtering device using a hollow fiber membrane module as a filtering material has been widely spread.

Each hollow fiber membrane is a hollow fiber membrane having an outer diameter of about 0.3 to 3 mm and a large number of fine permeation holes.
As a filtration material for ultrafiltration and reverse osmosis filtration, it can capture suspensions with a particle size of 0.1 μm or less, has a large filtration area per unit volume, and has excellent pressure resistance. Widely used in the fields of electronics industry, medicine, wastewater treatment, etc.

FIG. 5 shows a conventional hollow fiber membrane filtration device 1 of this type.
2 shows a vertical cross-section of an example of the structure, in which the inside of the closed container 2 is vertically and liquid-tightly partitioned into a filtration chamber 4a and a treatment liquid chamber 4b by a tube plate 3, and a plurality of hollow fiber membrane modules are provided in the filtration chamber 4a. 5 is hanging.

In the hollow fiber membrane module 5, a large number of fibrous hollow fiber membranes 6 are bundled, for example, in a U shape, and the end portions thereof are fixed with resin to form a module fixing portion 7. The module fixing portion 7 Each mounting hole 3a in the shape of a stepped hole of the tube sheet 3
It is fixed to the tube plate 3 by being inserted and fixed therein, and is suspended in the filtration chamber 4a.

This tube sheet 3 has its outer peripheral edge portion sealed with the closed container 2.
The upper and lower outer peripheral flanges 8 and 9 projecting outward at the outer peripheral edge portions of the body 2A and the lid 2B are sandwiched and fixed from above and below. Then, at the time of the backwashing operation, the backwashing air is supplied from the air inlet nozzle 10, and the air is jetted into each protective cylinder 13 from the plurality of air blowing nozzles 12 of the water spray plate 11.

To this end, the hollow fiber membranes 6 of each hollow fiber membrane module 5 are vibrated by the impact force of the bubbles rising in the liquid in the filtration chamber 4a, and the clad and the like adhering to the surface of the hollow fiber membranes are peeled off. To regenerate the filtration function of the hollow fiber membrane. The backwash water used for the backwash is the backwash water outlet nozzle 1 at the bottom of the filtration chamber 4a.
4 is discharged to a wastewater treatment facility (not shown).

The sprinkler plate 11 is composed of a plurality of hanging bolts 1.
5 is suspended from the tube plate 3 and fixed, and in FIG. 5, reference numeral 16 is a supply liquid inlet nozzle for supplying radioactive waste liquid, 17 is a vent pipe for discharging the air in the air layer 18, and 19 is a vent pipe. It is a processing liquid outlet nozzle.

[0010]

However, in the conventional hollow fiber membrane filtration apparatus 1 as described above, the upper ends of the openings of the plurality of protective cylinders 13 are fixed to the lower surface of the tube sheet 3 by welding 20. There is.

That is, there is an existing filtration device incorporating a filtering material such as a precoat filter other than the hollow fiber membrane 6 with a tube plate corresponding to the tube plate 2 of the hollow fiber membrane filtration device 1. When the existing filtration device is modified into the hollow fiber membrane filtration device 1, the upper ends of the openings of the plurality of protective cylinders 13 must be accurately positioned and welded and fixed to the tube plate of the existing filtration device. In addition to the complicated work, the tube plate of this existing filtration device is already contaminated with radiation, so there is a problem that a small amount of radiation is exposed during welding.
Further, since each protective cylinder 13 has a thin plate thickness and is suspended from the tube plate 3, its rigidity is not necessarily high.

Therefore, the present invention has been made in view of the above circumstances, and the purpose thereof is to reuse a tube plate of an existing non-hollow fiber membrane type filtration device as it is. Another object of the present invention is to provide a hollow fiber membrane filtration device which can simplify the work of remodeling the device and reduce the radiation dose. Another object is to enhance the rigidity and strength of the protective cylinder, while enhancing the air discharge efficiency during backwashing.

[0013]

According to the present invention, a plurality of protective cylinders 13 are prevented from being welded and fixed to the tube sheet 3.
It is configured as follows.

The invention according to claim 1 of the present application (hereinafter, referred to as the first
Of the invention), a tube plate partitioning the inside of a closed container into a lower filtration chamber and an upper processing liquid chamber in a liquid-tight manner, and a plurality of hollow fiber membrane modules attached to the tube plate and housed in the filtration chamber. And a hollow fiber having a protective cylinder for accommodating each of these hollow fiber membrane modules, and a sprinkler plate suspended from the tube sheet in the filtration chamber and provided with an outlet for blowing backwash air into each protective cylinder. In the membrane filtration device, each of the protection cylinders is
It is characterized in that it is fixed to the water spray plate without being fixed to the tube plate. The invention according to claim 2 of the present application (hereinafter,
The second invention) is characterized in that a gap is provided between each protective cylinder and the tube sheet in the first invention.

Further, in the invention according to claim 3 of the present application (hereinafter referred to as the third invention), the protection cylinders in the first or second invention are connected by a spacer in the radial direction to be integrated. Is characterized by.

Furthermore, the invention according to claim 4 of the present application (hereinafter, referred to as the fourth invention) is any one of the first to third inventions, and a gap is provided between each protection cylinder and the water spray plate. It is characterized by being provided.

[0017]

[Action]

 <First invention>

Since each protective cylinder is fixed to the water spray plate without being fixed to the tube plate, when the existing non-hollow fiber membrane type filtration device is remodeled into a hollow fiber membrane filtration device, the existing filtration device is used. It is not necessary to fix a plurality of protective cylinders to the tube sheet by welding, and it can be reused as it is.

Therefore, the non-hollow fiber membrane type existing filtration device can be remodeled into a hollow fiber membrane filtration device very easily, and at the time of welding the protective tube to the tube plate of the existing filtration device,
It is possible to prevent exposure to radiation by a tube sheet that is already contaminated with radiation. <Second invention>

Since the gaps are provided between the protective cylinders and the tube sheet in the first aspect of the invention, it is possible to improve the ventilation of the air accumulated in the gaps. Therefore, the air in this gap can be discharged to the outside with high efficiency by the vent pipe. <Third Invention> Since the protection cylinders of the first or second invention are connected by a spacer in the radial direction and integrated, the rigidity and strength of each protection cylinder can be increased. <Fourth invention>

Since a gap is provided between each of the protective cylinders of any one of the first to third aspects of the invention and the water spray plate, the clad at the time of backwashing can be efficiently discharged to the outside from this gap, and the backwashing effect is obtained. Can be increased.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view of an embodiment of the present invention, in which a hollow fiber membrane filtering device 21 is a closed container 22.
The inside is vertically and liquid-tightly partitioned into a filtration chamber 24a and a treatment liquid chamber 24b by a tube plate 23, and a plurality of hollow fiber membrane modules 25 are suspended in the filtration chamber 24a.

In each hollow fiber membrane module 25, a large number of fibrous hollow fiber membranes 26 are bound together, for example, in a U shape, and the end portions thereof are fixed by a resin or the like to form a module fixing portion 27. By fixing and fixing the fixing portion 27 in each stepped hole-shaped mounting hole 23a of the tube plate 23, the fixing portion 27 is fixed to the tube plate 23 and is suspended in the filtration chamber 24a. Each hollow fiber membrane 26 is a hollow fiber membrane having an outer diameter of about 0.3 to 3 mm and a large number of fine permeation holes, and a particle diameter of 0.1.
It can also capture suspended matter of μm or less, has a large filtration area per unit volume, and has excellent pressure resistance.

The outer peripheral portion of the tube sheet 23 is sealed with the closed container 21.
The upper and lower outer peripheral flanges 28 and 29 projecting outward from the outer peripheral edges of the body 22A and the lid 22B are sandwiched and fixed from above and below.

The hollow fiber membrane module 25 is housed in a cylindrical protective cylinder 30 whose upper and lower ends are open. The protective cylinder 30 is located between the upper end of the opening and the lower surface of the tube sheet 23 in the figure. For example, while providing an upper gap ga of about 10 to 30 mm, the lower end of the opening of each protection cylinder 30 is fixed to the water spray plate 32 by a fixed pin 31 having a cylindrical shape, for example.

That is, as shown in FIG.
A plurality of fixing pins 31 are respectively planted on the water spray plate 32 in the gaps between them, and the upper outer peripheral surface of each fixing pin 31 in the figure is fixed to the outer peripheral surface of the lower end portion of each protective cylinder 30 by welding. A lower gap gb of, for example, 10 to 30 mm is provided between the lower end of the opening of the protection cylinder 30 and the upper surface of the sprinkler plate 32 with each fixing pin 31.

Further, as shown in FIG. 2, a plurality of spacers 33 for connecting adjacent outer peripheral surfaces of the protection cylinders 30 in the radial direction are provided on the upper and lower portions of each protection cylinder 30, respectively.
The protection cylinder 30 having a small plate thickness and a low rigidity as a single body is integrated to enhance rigidity and strength.

As shown in FIG. 2, the water spray plate 32 is provided with air blowing nozzles 34 concentrically below the respective protection cylinders 30, and is provided on the outer peripheral edge portion of the water spray plate 32 in the circumferential direction. Plural suspension bolts 35 and 3 fixed at the pitch
It is hung by the tube sheet 23 by 5 ...

Each suspension bolt 35 has a plurality of rectangular piece-shaped supports 36, 36 ... Fixed to several positions in the vertical direction.
It is fixed to the outermost peripheral side surface of the integrated protection cylinder 30 and the outer peripheral edge of the sprinkling plate 32 to enhance the fixing strength of these.

A plurality of air blowing pipes 38 communicating with the air inlet nozzle 37 are provided below the water spray plate 32.
The air blown out from the air supplied from the air inlet nozzle 37
8 is once blown out, and further this air is blown out into the liquid from each air blowing nozzle 34.

The closed container 22 is provided with a backwash water outlet nozzle 39 at the bottom thereof, a treatment liquid outlet nozzle 40 is provided at the top of the lid 22B, and a vent pipe 41 and a supply liquid are provided on the side surface of the body 22A. An inlet nozzle 42 and an inlet nozzle 42 are provided respectively.

The inner end of the vent pipe 41 is the filtration chamber 24a.
Is opened in the air layer 43 in the gap between the liquid surface of the above and the lower surface of the tube sheet 23, and the air accumulated in the air layer 43 is discharged from the vent pipe 41 to the outside. Next, the operation of the present embodiment will be described.

The radioactive liquid waste generated from the nuclear power plant or the like is supplied to the feed liquid inlet nozzle 4 of the hollow fiber membrane filtration device 21.
2 is introduced into the filtration chamber 24a and passes through a myriad of fine permeation holes on the surface of each hollow fiber membrane 26, but foreign matter such as a clad larger than the diameter of the micropores cannot flow in and is separated and removed. The treatment liquid is filtered. The filtered treatment liquid passes through the hollow portion of the hollow fiber membrane 26, flows into the treatment liquid chamber 24b via the tube plate 23, and is then transferred from the treatment liquid outlet nozzle 40 to the outside of the system. By the way, an air layer 43 may be formed in the upper part of the filtration chamber 24a after the filtration of a predetermined volume of the supply liquid. This air layer 43 is a fine bubble in water,
Bubbles and the like adhering to the inner surface of the pipe or the surface of equipment are gradually accumulated and formed on the upper part during long-term operation.

Since the air layer 43 communicates in the lateral direction with the upper gap ga, the ventilation of the individual air is enhanced, so that the air in the air layer 43 is discharged from the vent pipe 41 to the outside with high efficiency.

When the clogging of the hollow fiber membranes 26 is expanded by this waste liquid filtration treatment and the permeation pressure loss thereof is increased, the clad or the like adhering to the surface of the hollow fiber membranes 26 is removed by backwashing.

That is, during the backwashing operation, the backwashing air is supplied from the air inlet nozzle 37 into the filtration chamber 24a, and the air is blown out from the air blowing pipe 38. This air temporarily accumulates below the water spray plate 33. When the air is accumulated in a certain amount or more, the air is ejected from the ejection nozzles 34 into the protection cylinders 30.

For this reason, air rises as bubbles in the liquid in the filtration chamber 24a, and the impact force of the bubbles causes the hollow fiber membranes 26 of each hollow fiber membrane module 25 to vibrate and adheres to the surface of the hollow fiber membranes. Foreign matter such as the clad is peeled off to regenerate the filtration function of the hollow fiber membrane 26. The backwash water used for this backwash is the backwash water outlet nozzle 39 at the bottom of the filtration chamber 24a.
Is discharged to a wastewater treatment facility (not shown).

Therefore, according to this embodiment, each protection tube 3
Since 0 is not welded to the tube sheet 23, when a non-hollow fiber membrane type existing filtration apparatus is modified to the hollow fiber membrane filtration apparatus 11 of this embodiment, the tube sheet of the existing filtration apparatus has a plurality of protections. Tube 3
Since it is not necessary to weld 0, the work efficiency of the remodeling work is correspondingly increased, and the radiation from the tube sheet is not exposed during the welding, and the safety is high.

The upper end of the opening of each protective cylinder 30 and the tube sheet 2
Since the upper gap ga is set on the lower surface of No. 3, the air layer 43
It is possible to increase the fluidity of the air accumulated in the air. Therefore, the air accumulated in the air layer 43 can be discharged from the vent pipe 41 to the outside with high efficiency. Furthermore, each protection cylinder 30
Since the spacers 33 are connected to each other and integrated, the rigidity and strength of each protection cylinder 30 can be increased.

Furthermore, since a lower gap gb is set between the lower ends of the openings of the protection cylinders 30 and the upper surface of the water spray plate 32 in the gap between the fixing pins 31 of the protection cylinders 30, the lower clearance gb is set. Foreign matter can be discharged from the lower gap gb to the outside of each protective cylinder 30 with high efficiency.

FIG. 3 shows a vertical cross-section of another embodiment of the present invention. This hollow fiber membrane filtration device 51 is designed to effectively reuse the existing long closed container 52 of the present invention. An example of the case applied to the long-body closed container 52 is shown.

In this case, the water spray plate 32 is suspended by the suspension bolts 53 obtained by lengthening the suspension bolts 35 of the above-mentioned embodiment in accordance with the length of the long closed container 52, and the backwash water outlet nozzle 39 is provided. Is provided with a backwash water outlet nozzle 54 that also serves as a supply liquid inlet nozzle, and the lower end of the opening of each protective cylinder 55 in which the axial length of the protective cylinder 30 is lengthened is fixed to the sprinkler plate 32 via a fixing pin 31. Since it is the same as the above-mentioned embodiment except for this, the same parts as those in FIG. 1 are denoted by the same reference numerals in FIG. 3, and their duplicated description is omitted.

In the embodiment shown in FIGS. 1 and 2,
Although the case where the lower gap gb is provided between each protection cylinder 30 and the water spray plate 32 has been described, the present invention is not limited to this, and each protection cylinder 30, as shown in FIG.
The lower end of each opening of 55 is fixed to the sprinkler plate 3 without the fixing pin 31.
It is fixed to the upper surface of 2 directly by welding, etc.
For example, arcuate lateral holes 60 may be formed in the lower end portion of 55, and foreign matter such as clad may be discharged from the lateral holes 60.

[0045]

As described above, the first invention of the present application is:
Since each protective cylinder is not fixed to the tube plate but is fixed to the water spray plate suspended on this tube plate, when modifying the existing non-hollow fiber membrane type filtration device to the hollow fiber membrane type, The protective cylinder can be reused as it is without being fixed to the tube plate of the existing filtration device by welding or the like.

For this reason, it is extremely easy to remodel the existing filtration device into a hollow fiber membrane type, and since it is not necessary to weld the protective tube to the tube plate of the existing filtration device, the tube plate is not welded at the time of welding. Exposure to radiation,
The safety can be further enhanced.

Further, in the second aspect of the present invention, since the gap is provided between each protection cylinder and the tube sheet, the fluidity of the air accumulated in the air layer formed in this gap can be enhanced, and the air layer It is possible to discharge the air accumulated in the outside with high efficiency.

Further, in the third invention of the present application, since the protection cylinders of the first or second invention are connected by a spacer in the radial direction to be integrated, the rigidity and strength in the radial direction of the protection cylinders are enhanced. be able to.

Furthermore, in the fourth invention of the present application, since a gap is provided between each of the protective cylinders and the water spray plate in the first to third inventions, foreign matter such as clad at the time of backwashing is removed from the gap. It can be discharged to the outside of the protective cylinder, and the backwash effect can be enhanced.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an embodiment of a hollow fiber membrane filtering device according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a vertical sectional view of another embodiment of the present invention.

FIG. 4 is an enlarged view of a main part of another embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional hollow fiber membrane filtration device.

[Explanation of symbols]

 21 Hollow Fiber Membrane Filtration Device 22 Airtight Container 23 Tube Plate 24a Filtration Chamber 24b Treatment Liquid Chamber 25 Hollow Fiber Membrane Module 26 Hollow Fiber Membrane 30 Protective Cylinder 31 Fixing Pin 32 Water Sprinkler 33 Spacer 35 Hanging Bolt 36 Support 52 Long Body Airtight Container 60 Lateral hole

Claims (4)

(57) [Claims] 1. A tube plate partitioning a sealed container into a lower filtration chamber and an upper treatment liquid chamber in a liquid-tight manner, and a plurality of hollow fiber membrane modules attached to the tube plate and housed in the filtration chamber. A hollow fiber membrane having a protective cylinder for accommodating each of these hollow fiber membrane modules, and a water sprinkler plate suspended from the tube sheet in the filtration chamber and provided with an outlet for blowing backwash air into each protective cylinder. In the filtration device, each of the protection cylinders is fixed to the water spray plate without being fixed to the tube plate, and the hollow fiber membrane filtration device is characterized. 2. The hollow fiber membrane filtration device according to claim 1, wherein a gap is provided between each protective cylinder and the tube sheet. 3. The protection cylinders are connected to each other in the radial direction by a spacer so as to be integrated with each other.
The hollow fiber membrane filtration device described. 4. The hollow fiber membrane filtration device according to claim 1, wherein a gap is provided between each protection cylinder and the water spray plate.