JPH0771622B2 - Hollow fiber membrane filtration device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a filtration device, and more particularly to a hollow fiber membrane filtration device using a hollow fiber membrane as a filter element.

[Conventional technology]

In a boiling water nuclear power plant, the primary system cooling water is boiled in a reactor to produce steam, and this steam drives a turbine directly connected to the generator, then condensed in a condenser and then condensed in the reactor. A return cycle is configured.

If impurities are contained in this primary system cooling water, there is a concern that these impurities may be activated by the irradiation of neutrons that accompany the nuclear fission reaction of the reactor.Therefore, a condensate purification system shall be installed in the above plant. Removes impurities from condensate,
It prevents impurities from being brought into the reactor.

In this condensate purification system, as a condensate filter for removing insoluble impurities in the condensate, conventionally, a filter element precoated with a powdery ion exchange resin has been used. However, in this precoat-type filtration device, the powdery ion-exchange resin, which is the precoat material removed by backwashing, became radioactive waste as a result of periodic backflow and reprecoating.

As a condensate filter for solving such a drawback, there is a filter using a hollow fiber polymer membrane as a filter element (see JP-A-60-61089). This is 10
Using a hollow fiber membrane having an outer diameter of about a few mm to 2 mm, the condensate is filtered by flowing the condensate from the outside to the inside of the membrane, and the filtered condensate is discharged from the open end of the hollow fiber membrane. Taken out. In such a condensate filtration device, a bundle of a plurality of hollow fiber membranes is bent in a U shape and the open ends are aligned in the same direction, or one end of a bundle of a plurality of linear hollow fiber membranes. One module was formed by closing one end and opening only one end, and each open end of a plurality of modules was connected to a hole formed in a partition plate separating the inlet side and the outlet side of the filtration device container. Therefore, due to the pressure loss of the water flowing through the hollow portion, the linear flow velocity (LV) of the water passing through the membrane cross section decreased as the distance from the open end increased, and the filtration flow rate decreased (see FIG. 8).

In order to improve this filtration characteristic, a bundle of a plurality of linear hollow fiber membranes has open ends at both ends, and a conduit provided at the center of the bundle to connect both open ends is set at 1 module, and one of the open ends is opened. It is known that the water flowing out from the end is guided to this water conduit, and the other open end is connected to a partition plate that divides the inside of the filtration device container into the inlet side and the outlet side ( JP-A-60-206405).

[Problems to be solved by the invention]

The conventional apparatus described in JP-A-60-206405 uses a filter module in which a water conduit is provided in the center of a hollow fiber membrane assembly, and the structure of the module is miniaturized and simplified. Due to lack of consideration, there were problems such as enlargement of filtration equipment, increase of radioactive waste generated when replacing consumable filter modules, and increase of filter module cost.

First, in the above-mentioned filter module, since the water conduit is provided in the central part of the module, the thickness of one module is thicker than that. For example, a boiling water nuclear power plant with an electric output of 1100 MW needs to treat approximately 6000 tons of condensate per hour, which requires the use of a large number of filter modules. However, when installing the filter module in the container of the filter device, it is necessary to install each filter module at a certain distance or more, and the size of the filter device is increased due to the large thickness of the filter element. There are drawbacks that are forced. Although the design life of a nuclear power plant is about 40 years, it is expected that the filter element module will need to be replaced once every 2-3 years as a consumable item. The film module taken out at the time of this exchange becomes radioactive waste. Therefore, the thicker the film module, the larger the waste volume, and the larger the amount of waste in the water pipe. Furthermore, since the water conduit was placed in the central part of the module, the cost of manufacturing the module was high.

An object of the present invention is to provide a filtration device capable of reducing the pressure loss during filtration and increasing the filtration treatment capacity without increasing the number of filter elements and complicating the structure.

[Means for solving problems]

In order to achieve the above object, the first invention of the present application is such that the inside of a container is formed by three compartments stacked in one direction by two partition plates, and a plurality of hollows are provided in the second compartment of the container. Both ends of the hollow fiber membrane of the filter element in which the fiber membranes are bound in parallel with each other with the both ends open in parallel are provided so as to communicate between the first and second compartments, and , A water conduit is provided in communication with the first and second compartments, the filtered water is supplied to the second compartment, and the filtered water is discharged from the first or second compartment. It is characterized by being configured.

Further, in the second invention of the present application, the inside of the container is formed by two partition chambers by one partition plate, and a plurality of hollow fiber membranes are bound in a state in which both ends thereof are opened in parallel at intervals. One end of the filter element is connected to one of the compartments of the container together with one end of a water conduit provided separately from the filter element and fixed to the partition plate, and the other ends of the plurality of filter elements are connected to each other. Along with the other end of the water pipe, it is connected to a lower header that connects the plurality of filter elements in a watertight manner, and is communicated with and integrated with the lower header. It is characterized in that it is configured to discharge water.

[Action]

According to the configurations of the first and second aspects of the invention, the fluid that has flowed into the filtration device has the center portion of the filter element as a boundary,
It flows to both ends. The fluid flowing to the end connected to the partition plate flows out of the device from the outlet side chamber, and the fluid flowing to the other end flows from the water conduit to the outlet side chamber and then flows out of the device. . Therefore, the filtration part of the hollow fiber membrane, which is the farthest from the open end of the hollow part, is the central part of the element, and the distance is half that of the one end closed type filter module, and the filtration characteristics are improved. Further, the filter element is a bundle of only hollow fiber membranes, and the size and simplification of the element can be achieved.

〔Example〕

Next, a first embodiment of the present invention will be described with reference to FIG. The container of the filtration device is composed of a main body 1, a lid 2, an inlet nozzle 3 into which water to be filtered flows and an outlet nozzle 4 from which filtered water flows out. As these materials, stainless steel or carbonated steel having excellent corrosion resistance and rubber or plastics lining is suitable. Container body 1
Inside, a lower partition plate 6 and an upper partition plate 7 are provided, and a space between them is connected by a plurality of water guiding pipes 8 arranged concentrically with the center of the main body 1. A rectifying plate 9 is provided at the center of the container body 1. Stainless steel is the most suitable material for the internal structure of the container body 1. A filter module 5, which is a plurality of filter elements, is further installed between the lower partition plate 6 and the upper partition plate 7. The details of this filter module 5 are shown in FIG.

In FIG. 2, a plurality of hollow fiber membranes 10 made of a hollow polymer membrane are bundled, and the lower end and the upper end thereof are end-face treated with a lower end treatment material 11 and an upper end treatment material 12 made of epoxy resin or the like. ing. These are stored in a cover 13 made of stainless steel or plastic,
An O-ring 15 is provided at the lower end of 13 and an O-ring 14 is provided at the upper end.

FIG. 3 shows the state of the lower end treatment of the hollow fiber membrane 10.
The hollow fiber membrane 10 has its end fixed by a lower end treatment material 11, and its hollow part is open. The situation of treating the upper end surface of the hollow fiber membrane 10 is similar to that of FIG. 3, and the hollow portion is also open.

Figure 4 shows the installation status of the Filter Module 5. The filter modules 5 are inserted from above the upper partition plate 7 toward the lower partition plates 6 into the holes formed in the respective partition plates 6. The O-ring 14 and the O-ring 15 close the gap between the hole of each partition plate 6 and the cover 13. To install or remove this filter module 5, open the lid 2 and open the main body 1
Above.

The flow of water during the filtration process is as shown by the arrow in FIG. The water flowing from the inlet nozzle 3 is rectified by the rectifying plate 9, and then flows into the inside from the outside of the hollow fiber membrane 10 of the filter module 5, and the water that flows into the upper side with the center in the height direction as a boundary. After flowing toward the upper partition plate 7, it exits the filter module 5 and exits the outlet nozzle 4. On the other hand, the water that has flowed into the lower side flows into the lower partition plate 6 side, then exits from the filter module 5, and flows out of the outlet nozzle 4 via the water conduit 8.

Next, a second embodiment will be described with reference to FIG. In this embodiment, the lower partition plate 6 in the embodiment of FIG. 1 is replaced by a lower head 17 made of stainless casting or the like. The filter element 5 which is a fill element is the same as that shown in FIG. 2 described in the first embodiment, and is inserted into the hole formed in the partition plate 7 from above the upper partition plate 7. , Connected to the lower Hezda 17. The details are shown in FIG.

In FIG. 6, the lower end of the filter module 5 is connected to the lower header 17, and the lower header 17 forms a flow path connecting the lower end of the filter module 5 and the water conduit 8. FIG. 7 shows a plan view of the lower head 17 as seen from above. In this embodiment, three filter modules are connected to one water pipe 8. The flow of water during operation of the filtration device of this example is shown by the arrows in FIG.

In FIG. 5, water is supplied from the lower nozzle 3, rectified by the rectifying plate 16, and then flows from the outside of the hollow fiber membrane 10 of the filter module 5 to the hollow portion to be filtered. Here, the water that has passed through the hollow fiber membrane 10 above the central portion in the height direction of the filter module 5 flows out from the upper open end of the filter module 5 and flows out from the outlet nozzle 4, and also in the central portion. Water that has passed through the lower hollow fiber membrane portion flows out from the outlet nozzle 4 via the lower header 17 and the water conduit 8.

The effect of using the filtration device of the above embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 shows the relationship between the linear flow velocity LV of water passing through the hollow fiber membrane in the filter module 5 and the height from the lower end of the filter module. The curve indicated by the symbol A shows the case of the conventional filter device using the filter module having the closed lower end, and the curve indicated by the symbol B shows the case of the filter device of the present invention. In the case of the present invention, the linear flux LV of water at each height is larger than that of the conventional one, and this is more remarkable in the lower height portion. This indicates that the present invention provides a larger filtration amount. FIG. 9 shows the relationship between the pressure drop filtration differential pressure due to the filtration of the filtration device and the linear flux LV of water averaged over the entire filtration device. As indicated by the symbol C, the curve indicates the characteristics of the conventional filtration apparatus using a filter module having a closed lower end, and the curve D indicates the characteristics of the filtration apparatus of the present invention. For the same filtration differential pressure, the present invention provides about twice the average linear flow velocity LV (that is, about twice the flow rate) as compared with the conventional one. Therefore, according to the present invention, the filtration treatment capacity is increased about twice.

〔The invention's effect〕

As described above, according to the present invention, it is possible to increase the filtration processing capacity up to about 2 times without increasing the amount of waste generated when the filter element is replaced, etc., and it is possible to downsize the apparatus, which is economical. Sexuality is greatly improved.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a first embodiment of the present invention, FIG. 2 is a partial sectional view of a filter module, FIG. 3 is an enlarged sectional view of an end portion of the filter module, and FIG. 4 is in FIG. An enlarged partial sectional view of the filter module connecting portion, FIG. 5 is a partial sectional view of a second embodiment of the present invention, and FIG. 6 is an enlarged partial sectional view of the filter module connecting portion in FIG.
FIG. 7 is a plan view of the lower head in FIG. 6, and FIG. 8 is a diagram showing the relationship between the linear flow velocity LV and the height above the lower part of the filter module of the filtration device according to the prior art and the present invention.
The figure is a diagram showing the relationship between the filtration differential pressure and the average LV of the filtration device in the prior art and the present invention. 1 ... Main body, 2 ... Lid, 3 ... Inlet nozzle, 4 ... Outlet nozzle, 5 ... Filter module, 6 ... Lower partition plate, 7 ... Upper partition plate, 8 ... Water conduit, 16 ……rectifier,
17 ... Lower Hezda.

Claims (2)

[Claims] 1. A container is formed by three partition chambers laminated in one direction by two partition plates, and a plurality of hollow membranes are arranged in parallel in a second partition chamber of the container. Both ends of the hollow fiber membrane of the filter element, which is bound in a state where both ends are opened, are arranged so as to communicate with each other between the first and second compartments and communicate with each other between the first and second compartments. And a water conduit is arranged, and the water to be filtered is supplied to the second compartment and the filtered water is discharged from the first or second compartment. . 2. A filter element in which the inside of a container is formed of two compartments by one partition plate, and a plurality of hollow fiber membranes are bound together with their both ends opened in parallel with each other at intervals. One end is connected to one partition of the container together with one end of a water conduit provided separately from the filter element and fixed to the partition plate, and the other ends of the plurality of filter elements are the other ends of the water conduit. Together with the lower header connecting the plurality of filter elements in a watertight manner, they are communicated and integrated with each other, the filtered water is supplied to the other compartment where the filter element is located, and the filtered water is discharged from the one compartment. A hollow fiber membrane filtration device having the above structure.