JPH0256223A - Hollow fiber-membrane filter - Google Patents

Abstract

PURPOSE:To uniformize the flow of a liq. to be treated by hanging plural hollow fiber-membrane modules in a vessel through a supporting plate, and fixing the outflow pipe for the liq. to the lid of the vessel. CONSTITUTION:The liq. to be treated flows into the vessel 1 from an inflow pipe 15, the flow direction is distributed obliquely upward and downward by a baffle 16, and the traveling distance to the bottom of an end plate 1a is increased. Consequently, the liq. is dispersed, and flows into the hollow fiber- membrane module 9. The clad in the liq. is deposited on the surface of the hollow-fiber membrane 13 of module 9, and the treated liq. passing through the inside of the membrane 13 is discharged to the outside of the vessel 1. At this time, the downward flow velocity at the lower end of the membrane 13 is uniformized, and the flow of the liq. to be treated toward the membrane 13 is uniformized. As a result, the time between the regenerations of the membrane can be prolonged.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to a non-auxiliary material type filtration device suitable for condensate purification systems of nuclear power plants, etc. This invention relates to a hollow fiber membrane type filtration device with improved properties.

(Prior art) In boiling water nuclear power plants, in order to reduce radiation exposure and maintain the integrity of the fuel, II; There is. As part of these countermeasures, recent nuclear power plants have installed filters pre-coated with powdered ion-exchange resin in addition to mixed-bed ion-exchange towers as pre-filtration devices to improve the crud removal performance of condensate purification systems. It is installed.

However, since this type of prefiltration device generates a large amount of used ion exchange resin as secondary radioactive waste, there is room for improvement in storage, processing, operating costs, etc. of waste resin. Therefore, there is a need to develop a non-auxiliary material type prefiltration device that generates less secondary radioactive waste, requires less space, and has low running costs.

In response to such demands, attempts have recently been made to use hollow fiber membrane filters, which are used in radioactive waste treatment facilities, as non-auxiliary prefiltration devices for condensate purification systems.

FIG. 9 shows a conventional hollow fiber membrane type condensate filtration device of this type, which will be explained below.

In FIG. 9, reference numeral 1 denotes a cylindrical container having a closed structure and partitioned from a lid 2 by a support plate 3. As shown in FIG.

An inlet pipe 4 and a drain pipe 5 for the liquid to be treated are provided on the lower end plate 1a of the container 1, and a vent pipe 6 is provided on the upper side surface. The lid 2 is provided with a processing liquid outflow pipe 7 that also serves as a backwashing air inflow pipe.

Inside the container 1, a hollow fiber membrane module structure 9 is arranged, which is a bundle of a large number of hollow fiber membranes 13 whose upper ends are fixed to a support plate 3 via a presser plate 8. A tube 10 is provided.

The lower ends of the protective tubes 10 are connected to each other via a connecting part 11. Further, below the module structure 9, an air pipe 12 having a large number of nozzles 12A is provided.

In the hollow fiber membrane filtration device configured as described above, the liquid to be treated flows into the container 1 from the inflow pipe 4 and flows into the protection pipe 10. Then, since the hollow fiber membrane 13 is a type of pulp filter, only water of the liquid to be treated passes through, and solid matter such as crud adheres to the surface of the hollow membrane fiber 13 and is separated and removed.

The water that has permeated into the hollow fiber membrane 13 passes through the inside of the module structure 9 and flows to the upper side of the support plate 3 as purified water (processing liquid). This purified water is discharged to the outside from the processing liquid outflow pipe 7 of the lid 2.

When condensate filtration operation is performed for a long time in this condensate filtration device, a large amount of foreign matter such as unfiltered crud adheres to the surface of the hollow fiber membrane 13, and the filtration performance of the hollow fiber membrane 13 decreases. Therefore, in order to restore the filtration performance of the hollow fiber membrane 13, a backwash operation is performed at regular intervals.

During this backwashing operation, a bubbling operation is also performed in parallel. In this backwashing operation, the circulating water in the lid 2 first flows into the inside of the hollow fiber membrane 13 and flows out from the outside. On this occasion,
The vent pipe 6 is opened to discharge the water increased by the backflow, and at the same time, the air is allowed to flow out from the nozzle 12a of the air pipe 12, generating bubbles in the protection pipe 10 and vibrating the hollow fiber membrane 13. Air bubbles in the protection tube 10 are discharged from the protection tube 10 through holes provided in the upper part of the protection tube 10, thereby preventing the protection tube 10 from being filled with air.

Through this backwashing operation, the crud attached to the surface of the hollow fiber membrane 13 is removed, the hollow fiber membrane 13 recovers its normal filtration performance, and the liquid to be treated in the container 1 is discharged from the drain pipe 5 and drained. be done.

(Problems to be Solved by the Invention) In the conventional hollow fiber membrane type filtration device, the inflow pipe 4 for flowing the liquid to be treated into the hollow fiber membrane 13 is provided on the end plate 1a at a position offset from the center line of the bottom of the container 1. Also, the drain pipe 5 is connected to the container 1.
It is provided on the end plate 1a directly below along the central axis. Further, a buffer plate 14 is provided on the overhang of the inflow pipe 4 so that the liquid to be treated does not flow in from the inflow pipe 4 and directly hit the hollow fiber membrane module structure 9 . Therefore, the liquid to be treated flows out from the opening provided on the lower side of the buffer plate 14 and flows upward along the inner wall of the container 1. However, since the inflow pipe 4 is not located at the center of the container 1, the liquid to be treated flows unevenly between the container buffer plate 14 and the lower end of the protection tube 10, and the hollow fiber membrane module structure 9 has an uneven flow. There is a problem with the flow of water being processed at different flow rates.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a hollow fiber membrane type filtration device that improves the uniformity of a liquid to be treated flowing into a hollow fiber membrane module structure and reduces the size of the device.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method in which a plurality of hollow fiber membrane module structures are vertically disposed in a container via a support plate, an inflow pipe for a liquid to be treated is attached to a side wall of the container, and the An outflow pipe for the processing liquid is attached to the container wall located at the top of the plate, the inflow pipe has an opening in one or two directions in front of the inlet in the container, and a baffle plate is provided in the horizontal direction in the opening. It is characterized by:

Further, a plurality of hollow fiber membrane module structures are vertically disposed inside the container via a support plate, an inflow pipe for the liquid to be treated is attached to the wall of the container below the support plate, and an inflow pipe for the liquid to be treated is attached to the lid of the container. It is characterized in that an outflow pipe is attached and a radial baffle plate is provided at the bottom of the container.

(Function) The liquid to be treated flows into the container from an inflow pipe attached to the upper side of the container, and a protective pipe is provided between the open end of the inflow pipe and a protection pipe surrounding the hollow fiber membrane module structure. Using baffles or flow deflectors, the direction of the flow is directed diagonally downward or upward, increasing the distance to the bottom, and when the liquid to be treated reaches the mirror plate at the bottom of the container, the flow direction is changed upward and passes through the hollow fiber membrane. Flow into the modular structure. The cladding in the liquid to be treated adheres to the surface of the hollow fiber membrane of this module structure, and the treated liquid that has passed through the hollow fiber membrane flows out of the container from the outflow pipe. In this filtration device, the flow rate does not decrease due to the deflected flow of the liquid to be treated by the baffle plate, and the flow of the liquid to be treated to the hollow fiber membrane can be made uniform.

(Example) A first example of a hollow fiber membrane type filtration device according to the present invention will be described with reference to FIGS. 1 and 2. Note that in FIG. 1, the same parts as in FIG. 9 are given the same reference numerals, and explanations of the overlapping parts are omitted.

The difference between the first embodiment and the conventional example is that, as is clear from FIGS. 1 and 2, an inflow pipe 15 for the liquid to be treated is provided on the upper side of the container 1, and this inflow pipe 15 and a protection pipe 10
A box-shaped baffle plate 16 as shown in FIG. 2 is provided between the two. In addition, conventionally, an inlet pipe 4 for the liquid to be treated was provided on the end plate of the container 1, and a vent pipe 6 was provided on the side surface of the container 1.
This is due to the deletion of the . Baffle plate 16 Figure 2 (b)
As shown in FIG.
As shown in Figure (C), the negative side also has an opening 16b. Note that the inflow pipe 15 can also serve as a vent pipe for air removal, etc.

Therefore, in the hollow fiber membrane filtration device configured as described above, the liquid to be treated flows into the container 1 from the inflow pipe 15, and the baffle plate 16
As a result, the direction of the flow is dispersed diagonally downward and upward, and the reaching distance to the bottom of the mirror plate 1a is lengthened. As the reaching distance becomes longer, the liquid to be treated is dispersed and flows into the hollow fiber membrane module structure 9. Crud in the liquid to be treated adheres to the surface of the hollow fiber membrane 13 of this module structure 9, and the treated liquid that has passed through the hollow fiber membrane 13 flows out of the container 1. At this time, since the deflected flow of the liquid to be treated travels a distance equal to the length of the hollow fiber membrane 13, the downward flow velocity at the lower end of the hollow fiber membrane 13 becomes uniform, and the flow rate does not decrease (the hollow fiber membrane 13 The flow of the liquid to be treated can be made equal.

3 and 4 show other examples of box-shaped baffle plates 17, 18, in each figure (a) is a longitudinal cross-sectional view, and (b) is (
a) A sectional view taken along the line B-B' in the figure, (c) a cross-sectional view taken along the line c- in the figure (a).
It is a sectional view taken along the c′ arrow.

The box-shaped baffle plate 17 shown in FIG. 3 has an opening 17a on the lower side in only one direction, and a large number of small holes 17b on the top and side surfaces.

The box-shaped baffle plate 18 shown in FIG. 4 has openings 18a on the upper and lower surfaces.
and openings 18b on both sides.

The functions and effects of these baffle plates 17 and 18 are substantially the same as those of the baffle plate 16 shown in FIG. 2 described above, so a description thereof will be omitted.

FIGS. 5 and 6 show a second embodiment of the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals and explanations of overlapping parts will be omitted.

This second embodiment differs from the conventional example in that, as is clear from FIG. A deflection plate 19 is provided in the container 1, and a radial baffle plate 20 is provided on the lower end plate 1a of the container 1, as shown in an enlarged plan view in FIG. Another advantage is that the inflow pipe 4 for the liquid to be treated, which was provided on the end plate 1a, and the vent pipe 6, which was provided on the side surface, have been removed. The other parts have the same configuration as the first embodiment.

In the hollow fiber membrane filtration device having the above structure, the liquid to be treated flows into the container 1 from the inflow pipe 15, collides with the drift plate 19, flows down, and flows along the inner wall surface of the container 1. The water flows down near the baffle plate 20 provided on the lower mirror plate 1a, and the direction of the flow is dispersed by the baffle plate 20. In particular, the flow directly below the inflow pipe 15 is fast and can be dispersed by the baffle plate 20. The direction of the dispersed flow from the mirror plate 1a toward the baffle plate 20 is reversed, changed upward, and uniformly flows into the hollow plate membrane module structure 9. The surface of the hollow fiber membrane 13 of this module structure 9 is covered with crud in the liquid to be treated, and the treated liquid that has passed through the hollow fiber membrane 13 flows out of the container 1. At this time, since the deflected flow of the liquid to be treated travels a distance equal to the length of the hollow fiber membrane 13, the downward flow velocity at the lower end of the hollow fiber membrane 13 becomes uniform, and the hollow fiber membrane 1 The flow of the liquid to be treated can be made equal.

FIG. 7 is a curve diagram showing the flow rate distribution in the inner bottom of the container, that is, the end plate in the second embodiment, where the vertical axis shows the flow rate, the horizontal axis shows the radial direction of the inner bottom of the container, and curve 21 shows the flow rate distribution in the container inner bottom, that is, the head plate in the second embodiment. , curve 22 respectively show the second embodiment.

As is clear from the curve 22 in FIG. 7, by providing the baffle plate 20, the flow rate in the center can be dispersed to the periphery, thereby improving the dispersion effect of the flow of the liquid to be treated.

FIG. 8 is a longitudinal sectional view showing a third embodiment of the present invention, which is the same as the second embodiment except that the baffle plate 23 provided on the mirror plate 1a is formed into a cylindrical shape. The effects of this embodiment are the same as those of the second embodiment, so the explanation thereof will be omitted.

In addition to forming a curvature surface on the baffle plate 23, the wall surface can also be sloped in the vertical direction, and a gap can be provided between it and the bottom of the mirror plate to serve as a flow path. Further, by providing a large number of small holes in the baffle plate, it is possible to provide a better dispersion effect.

[Effects of the Invention] According to the present invention, by providing an inflow pipe and a baffle plate for the liquid to be treated on the upper side wall of the container, the flow of the liquid to be treated becomes uniform, and the amount of clubs etc. removed by the hollow fiber membrane is reduced. becomes constant. Therefore, it is possible to extend the regeneration period of the hollow fiber membrane, and accordingly, the life of the hollow fiber membrane can be extended. Furthermore, since the length of the container can be shortened, the container can be made compact, which not only reduces production costs but also eases the restrictions on transportation and installation, thereby improving economic efficiency.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a first embodiment of the hollow fiber membrane type filtration device according to the present invention, FIGS. 2 to 4 show examples of the baffle plates in FIG. 1, and FIG. 4(a) is a longitudinal sectional view showing the baffle plate, FIG. 4(b) is a sectional view taken along the line B-B' in FIG. A sectional view in the viewing direction; FIG. 5 is a longitudinal sectional view showing a second embodiment of the present invention;
Fig. 6 is a cross-sectional view showing an enlarged main part of Fig. 5, Fig. 7 is a characteristic diagram showing the flow rate distribution in the container in Fig. 5, and Fig. 8
The figure is a longitudinal sectional view showing a third embodiment of the present invention, and FIG. 9 is a longitudinal sectional view showing a conventional hollow fiber membrane type filtration device. 1... Container 2... Lid 3... Support plate 4... Inflow pipe 5... ......Drain pipe 6...Bent pipe 7...Outflow pipe 8...Press plate 9... ...Hollow fiber membrane module structure 10.
......Protection tube 11...Connection section 12...Air piping 13...Hollow fiber membrane 14... ......Buffer plate 15...Inflow pipe 16.17.18...Box-shaped baffle plate 19...Baffle plate 20... ...Number of radial obstacles 21...Conventional example 22...Second embodiment (b) Fig. 3 Fig. 7

Claims (2)

[Claims] (1) A plurality of hollow fiber membrane module structures are installed vertically in a container via a support plate, an inflow pipe for the liquid to be treated is attached to the side wall of the container, and the container wall located above the support plate is treated. A liquid outflow pipe is attached, the inflow pipe has an opening in one direction or two directions in front of the inflow port in the container, and a box-shaped baffle plate is provided in the horizontal direction in the opening. Hollow fiber membrane type filtration device. (2) A plurality of hollow fiber membrane module structures are vertically disposed in a container via a support plate, and an inflow pipe for the liquid to be treated is attached to the container wall below the support plate, and is located above the support plate. 1. A hollow fiber membrane filtration device, characterized in that an outflow pipe for a processing liquid is attached to a wall of the container, and a radial baffle plate is provided at the bottom of the container.