JPS62180707A - Hollow yarn membrane filter and its backwashing method - Google Patents

Abstract

PURPOSE:To sufficiently backwash off the iron clad, etc., deposited on the pore of the hollow yarn by providing a hole for piercing and fixing each hollow yarn and a gas inlet hole to the lower shield of the hollow yarn bundle, and arranging a gas sparger. CONSTITUTION:The hollow yarn bundle supporting plates are provided at the upper and lower parts in a filter vessel, and a hollow yarn bundle nozzle 14 is inserted in the lower hollow yarn bundle supporting plate 12. In this hollow yarn membrane filter, the hole for piercing and fixing a hollow yarn 19 is provided to the lower hollow yarn bundle shield 16, a gas inlet 16A is formed at the center of the shield, and the gas sparger 18 provided with a check ball 17 to be abutted on the gas inlet hole 16A is furnished. In backwashing, a high- pressure gas is introduced to form a gas layer on the lower surface of the supporting plate 12 and in the nozzle 14. The check ball 17 is pushed up by the gas, the gas is spouted from the gas sparger 18, and microvibration is provided to the hollow yarn 19. The air introduced from the nozzle 14 is forced into the inside of each hollow yarn 19 from the hollow yarn fixing hole of the shield 16, the pore of the hollow yarn 19 is expanded, and the clogging materials are removed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hollow fiber membrane filter and a backwashing method thereof;
In particular, the present invention relates to a hollow fiber membrane filter used in condensate filtration equipment at the end of nuclear power generation to remove iron cruciate, etc. from water supply, and a method for backwashing the same.

[Conventional technology]

Hollow fiber membrane filters are described, for example, in Japanese Patent Application Laid-open No. 60-61089.
As described in "Condensate purification method", in order to efficiently purify the condensate of boiling water reactors, it is installed in the condensate purification system.
It removes iron cladding, etc. from the turbine condensate of steam generated in a nuclear reactor, and has a structure in which a bundle of hollow fibers (modules) is suspended from the upper tube plate of the filter.

[Problem that the invention seeks to solve]

In such a hollow fiber membrane filter, by continuous operation,
In the past, when the iron cladding etc. became clogged and the differential pressure rose, backwashing was performed by blowing air.

However, since air was simply introduced into the hollow fiber bundle from the outside, the pores (small holes) of the hollow fibers were forced into a state where deposits such as iron particles were forced onto them, making complete backwashing impossible. I couldn't expect it.

As the operation continued, the initial differential pressure gradually increased, shortening the operating life of the hollow fiber membrane filter.

An object of the present invention is to provide a hollow fiber membrane filter having a structure capable of sufficiently backwashing iron cladding and the like adhering to the pores of hollow fibers, and a method for backwashing the same.

[Means for solving problems]

In order to achieve the above object, the present invention provides a structure in which a lower shield of a hollow fiber bundle is provided with a hole through which each hollow fiber is attached, a gas inlet hole is provided in the center of the shield, and a gas sparger is arranged above the hole, and a gas inlet hole is provided in the center of the shield. The proposed method is to expand the pores of each hollow fiber from the inside by pumping gas from the gas sparger, and to vibrate the hollow fibers with the gas ejected from the gas sparger for backwashing.

[Effect]

In the case of clogging, the conventional backwashing method involves introducing air into the outer cylinder of the hollow fiber bundle (module), so although there is a gas flow between the hollow fibers, the effect of the gas on removing deposits is small.

This is the result of various studies using full-scale experimental equipment.

It has been found that by providing a gas inlet hole in the center of the bottom of the hollow fiber bundle (module), allowing gas to enter from the center of the hollow fiber bundle and sending the gas toward the outer periphery of the hollow fiber bundle, the cleaning effect due to micro vibrations is great. Ta.

It has also been found that applying gas pressure from inside the hollow fibers to expand the pores of the hollow fibers with air bubbles makes it easier to remove clogs.

Furthermore, when gas pressure is applied from inside the hollow fiber, the hollow fiber can be moved in water by Bourdon tube action, and a rinsing effect can be expected.

[Real/flow side]

A preferred embodiment of the present invention is shown in FIGS. 1, 2, 3, etc.
Explain with reference to.

Figure 1 shows an example of the overall structure of a condensate system hollow fiber membrane filter, Figure 2 shows the upper part of the hollow fiber bundle (module) and the mounting section, and Figure 3 shows the details of the lower part of the hollow fiber bundle. This is what is shown.

The hollow fiber membrane filter of this example is J7j [installed in the condensate system that supplies water to the child reactor to remove iron cladding from the water supply.

Inside, the container structure of the hollow fiber membrane filter consists of a cylindrical container body that receives high pressure from the water supply. Upper mirror plate 2. Lower mirror plate 3;
It consists of skirt-like legs 4 that support the 171 body, and a fuselage flange 5 for opening when inspecting the internal structure. At the top there are 6 filtrate inlet nozzles) and at the bottom there are 7 filtrate outlet nozzles. reverse? A gas inlet nozzle 8 for pre-cleaning and a drain outlet nozzle 9 for discharging backwashed substances are installed.

Inside the filter container, there is a hollow fiber bundle (module/L/) 1
1, an upper hollow fiber bundle support plate 12 that supports the hollow fiber bundle 11 during installation, a lower hollow fiber bundle support plate 12 into which the hollow fiber bundle nozzle 14 is inserted, and a lower support plate that supports the hollow fiber bundle 11 via this support plate 12. There are 13 supports. 15 is a hollow fiber bundle 11
and the lower hollow fiber buttock support plate 12.
ring).

Prevents leakage of iron cladding, etc. from normal operation filtrate.

In addition, 20 is a hollow fiber east upper shield.

The structural features of the hollow fiber membrane filter according to the present invention are as follows.

A hole for penetrating the hollow fiber 19 into the lower shield 16 of the hollow fiber bundle and a gas inlet hole 16A are formed in the central portion, and a non-return ball 1 contacts the gas inlet hole 16A.
7 is provided with a gas sparger 18. The check ball 17 normally prevents unfiltered reactor water from passing through to the bottom when filtering is appropriate, while creating a passage for gas to the gas sparger 18 during backwashing.

The operation of the filter having such a structure will be explained next.

During normal filtration, the liquid to be filtered is introduced from the filtrate inlet nozzle 6. This liquid is applied to the upper hollow fiber bundle support plate 10
The hollow fibers 19 pass through the holes on the side of the hollow fiber bundle 11 from the inlet holes
reach. Here, impurities such as iron cladding are present in the hollow fiber 19.
It attaches to the outside of the body and is filtered. The filtrate passes inside the hollow fiber 19, passes through the hollow fiber bundle lower shield 16, the hollow fiber bundle nozzle 14, and the filtration outlet nozzle 7, and is again supplied to the reactor. In this case, the gas inlet nozzle 8 and the drain outlet nozzle 9 are closed by a valve installed in the external connection pipe.

If the operation is continued in this state, the hollow fibers 19 will become clogged due to the accumulation of iron cladding, etc., and the differential pressure will increase, so a backwashing operation for regeneration is performed at approximately regular intervals.

Backwash operation is performed using the filtrate inlet nozzle 6 and filtrate outlet nozzle 7.
Close the valve of the pipe connected to the gas inlet nozzle 8.
This is done by opening the piping valve of the drain outlet nozzle 9 and letting high pressure gas flow in from the gas inlet nozzle 8.

The high-pressure gas lifts the liquid in the container and forms a gas layer on the lower surface of the lower hollow fiber bundle support plate 12 and inside the hollow fiber bundle nozzle 14. This gas pushes up the check ball 17 that is in contact with the gas inlet hole 16A of the hollow fiber bundle lower shield 16, is ejected from the gas sparger 18, and gives a slight vibration to the hollow fibers 19 in the hollow fiber bundle 11. The air flowing in from the hollow fiber bundle nozzle 14 also. It also flows into each hollow fiber 19 from the hollow fiber attachment hole drilled in the lower shield 16 of the hollow fiber bundle, and gas pressure is applied to the inside of the hollow fiber to perform cleaning with the gas layer and to open the pores of each hollow fiber 19. Spread it out and remove any clogs.
- Furthermore, when gas pressure is applied to the inside of the hollow fibers 19, the hollow fibers 19 move in water due to Bourdon tube action, resulting in a rinsing effect.

The adducts thus separated from the hollow fibers are discharged from the drain outlet 9.

〔Effect of the invention〕

According to the present invention, the lower shield of the hollow fiber bundle is provided with a hole through which each hollow fiber is passed, and a gas inlet hole is provided in the center of the shield, and a gas sparger is arranged above the hole.

During backwashing, gas is pumped from the bottom of the shield to expand the pores of each hollow fiber from the inside, and the gas ejected from the gas sparger causes the hollow fibers to vibrate, thereby almost completely removing iron cladding, etc. attached to the pores of the hollow fibers. Backwashing is possible, which has the effect of significantly extending the operating life of the hollow fiber membrane filter.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing the overall structure of the hollow fiber membrane filter according to the present invention, Fig. 2 is a side sectional view showing details of the upper part of the hollow fiber bundle, and Fig. 3 is a side sectional view of the lower part of the hollow fiber bundle. It is a side sectional view showing details. 1... Hollow fiber membrane filter body, 2... Upper head plate, 3...
... Lower end plate, 4 ... Skirt leg, 5 ... Body flange, 6 ... Filtrate inlet nozzle, 7 ... Filtrate outlet nozzle, 8 ... Gas inlet nozzle, 9 ... Drain Outlet nozzle, 10... Upper hollow fiber bundle support plate, 11... Hollow fiber bundle (module), 12... Lower hollow fiber bundle support plate, 13... Lower support plate support, 14... Hollow Yarn bundle nozzle, 15... Packing, 16... Hollow fiber bundle lower shield, 16A... Gas inlet hole, 17... Check ball, 18... Gas sparger, 19... Hollow fiber , 20...Hollow fiber east upper shield.

Claims (1)

[Claims] 1. A closed container is divided into upper and lower spaces by a hollow fiber bundle support plate,
In a hollow fiber membrane filter in which a hollow fiber bundle is arranged in the upper space, an unfiltered liquid containing iron cladding, etc. flows into the upper space, is filtered by the hollow fiber membrane, and flows out from a hollow fiber bundle nozzle opened in the lower space, A hollow fiber bundle lower shield having a hole for penetrating the hollow fiber and a gas inlet hole in the center thereof at the lower end of the hollow fiber bundle, and a non-return check placed on the shield and abutting the gas inlet hole. A hollow fiber membrane filter characterized in that it is equipped with a gas sparger equipped with a gas sparger. 2. Divide the airtight container into upper and lower spaces using a hollow fiber bundle support plate,
A hollow fiber bundle is placed on a lower shield in which a hollow fiber bundle is arranged in the upper space, a hole for penetrating the hollow fibers is formed at the lower end of the hollow fiber bundle, and a gas inlet hole is formed in the center part, and the hollow fiber bundle is placed on the shield. and a gas sparger equipped with a check ball that abuts the gas inlet hole, and unfiltered liquid containing iron clad etc. flows into the upper space and is filtered by a hollow fiber membrane, and the hollow fiber opens into the lower space. In a method for backwashing a hollow fiber membrane filter that is discharged from a bundle nozzle, gas is pressurized from the lower space through the hollow fiber bundle nozzle to the lower part of the hollow fiber bundle lower shield, and the gas is sent from inside the lower end of each hollow fiber to clean the hollow fibers. At the same time as opening the pores of the fibers, gas is ejected into the hollow fiber bundle through the gas inlet hole and the gas sparger to slightly vibrate each hollow fiber, thereby removing iron cladding etc. attached to the pores of the hollow fibers. A method for backwashing a hollow fiber membrane filter, which is characterized by removing the membrane.