JP5041688B2 - Filtration filter coating method - Google Patents

Description

The present invention relates to a method of coating a filtration filter in the filtration apparatus used in power plants, particularly nuclear power plants relates to a coating method of the filtration filter in the filtration apparatus used in condensate treatment for thermal power plants.

Condensate treatment facilities in nuclear power plants and the like are equipped with a filtration device that removes suspended substances such as iron oxide contained in the condensate that is the treated water, and a demineralizer that removes ionic impurities such as chlorine ions. It is prepared for. Among these, as a filtration apparatus, what equipped the hollow fiber membrane provided with many micropores as a filtration membrane in recent years is used a lot. In the filter using the precoat material, a large amount of used filter aid is contained in the washing effluent, which increases the burden on the radioactive waste treatment system. However, when a hollow fiber membrane is used, such a filter is used. there is no problem. However, since the hollow fiber membrane directly captures suspended substances, iron oxide, etc., which is relatively sticky, does not easily peel off from the membrane surface, and the initial differential pressure increases with each washing. It was. In view of this, the present applicant formed a coating of iron oxide fine particles with good peelability on the surface of the membrane in advance, and captured the suspended substance by washing by capturing the suspended substance through the coating. The technique which peels a substance with a film and suppresses the raise of the initial differential pressure | voltage after washing | cleaning by this is proposed (refer patent document 1).
Japanese Patent Publication No. 6-24612

In forming a coating film of iron oxide fine particles, in Patent Document 1, a water tank for holding water containing the iron oxide fine particles is attached, and flows into the filtration tower from the raw water inflow pipe. Although not specified in Patent Document 1, in order to flow into the filtration tower through the raw water inflow pipe, a pump for pumping must be provided, which leads to a complicated structure and an increase in cost. It was. On the other hand, as a method that does not use a pump, the upper lid of the filtration tower is removed and opened, and iron oxide is also introduced from there. However, filtration that is always in operation like a power plant condensate filtration device. In the apparatus, there is an inconvenience that the timing at which the upper lid can be removed is limited to a periodic inspection. In addition, the work cost for opening the top cover increases, and the number of opportunities for workers to be exposed at the nuclear power plant increases.

The present invention has been made in view of the above, and without using a pump, and without performing the opening operation of the upper lid, the membrane surface contamination preventive agent can be attached to the filtration membrane surface with a simple configuration, It aims at providing the coating method of the filtration filter in the filtration apparatus which can aim at reduction of cost.

In order to solve the above-mentioned problems, in the present invention according to claim 1, the filtration treatment is started on the surface of the filtration membrane of the filtration filter disposed in the primary chamber of the filtration tower for capturing suspended substances in the water to be treated. Before, a method for coating a filtration filter in which iron oxide or iron hydroxide as a membrane surface contamination inhibitor is attached in advance, wherein the membrane surface contamination inhibitor is introduced into the primary chamber of the filtration tower using gravity And then, scrubbing by introducing compressed air into the primary chamber, and providing the membrane surface antifouling agent on the filtration membrane surface of the filtration filter.
According to a second aspect of the present invention, there is provided the filtration filter coating method according to the first aspect, wherein the compressed air is scrubbed by being introduced from a compressed air introduction pipe for cleaning connected to the primary chamber. provide.
In this invention of Claim 3, the water containing the said membrane | film | coat surface contamination | pollution prevention agent hold | maintained at the pollution inhibitor dispersion tank installed in the high place rather than the connection position of the introductory pipe connected to the primary chamber of the said filtration tower. The filtration filter coating method according to claim 1 or 2, wherein the filter is introduced into the primary chamber of the filtration tower using gravity through the introduction pipe.
In this invention of Claim 4, the said filtration filter is a hollow fiber membrane filter, The coating method of the filtration filter of Claim 1 or 2 characterized by the above-mentioned is provided.
In this invention of Claim 5, the said filtration filter is installed for the condensate treatment of a power plant, The coating method of the filtration filter of any one of Claims 1-4 characterized by the above-mentioned. provide.

The present invention provides a membrane surface contamination preventive agent by, for example, installing a contamination inhibitor dispersion tank holding water in which the membrane surface contamination inhibitor is dispersed at a higher position than the connection position between the filtration tower and the introduction pipe. It is characterized by being introduced into the filtration tower by gravity. Therefore, when the membrane surface contamination preventive agent is attached to the filtration membrane, the water in which the membrane surface contamination preventive agent is dispersed is introduced into the primary chamber of the filtration tower by gravity if the introduction pipe is opened. Therefore, it is not necessary to open the top lid of the filtration tower, and it is not necessary to provide a pump for introducing water in which the membrane surface contamination inhibitor is dispersed, and to introduce the membrane surface contamination inhibitor. This simplifies the apparatus configuration and contributes to the cost reduction. In addition, by introducing compressed air and scrubbing, the membrane surface contamination preventive agent is uniformly agitated, and the membrane surface contamination preventive agent can be adhered almost evenly to the membrane surface of the filtration filter.

  Hereinafter, the present invention will be described in more detail based on embodiments shown in the drawings. FIG. 1 is a diagram illustrating an example of a processing system of a power plant in which the filtration device 10 according to the present embodiment is used, and FIG. 2 is a diagram illustrating a structure of the filtration device 10.

  As shown in FIG. 1, the steam generated by the steam generator 100 such as a nuclear reactor rotates the steam turbine 110, is then cooled by the condenser 120, is condensed, and becomes condensate. Condensate is sent to the condensate treatment facility 140 by the condensate pump 130. The water treated by the condensate treatment facility 140 is sent to the steam generator 100 again. Among these, the condensate treatment facility 140 includes a filtration device 10 according to the present embodiment that removes suspended substances such as iron oxide generated from a condensate pipe, a steam pipe, and the like, and a demineralizer 150 that removes ionic impurities. It is configured with.

  In the condensate treatment facility 140, the filtration apparatus 10 of the present embodiment used for removing suspended substances in the condensate, as shown in FIG. 2, is a filtration tower 20, an introduction pipe 40, and a pollution inhibitor dispersion tank. 50.

  The filtration tower 20 includes a primary chamber 22 into which treated water flows and a secondary chamber 23 through which filtered treated water passes through a filter fixing plate 21 fixedly disposed therein. . A large number of hollow fiber membrane filters 24, which are filtration filters using hollow fiber membranes, are supported on the filter fixing plate 21. Specifically, the upper end of each hollow fiber membrane filter 24 is supported by being fixed to the filter fixing plate 21. A treated water inflow pipe 25 is connected to the lower part of the primary chamber 22, and a regeneration water inflow pipe 31 is connected to the inflow pipe 25. In addition, an outlet pipe 26 is connected to the upper part of the secondary chamber 23 to send the treated water filtered by passing through the hollow fiber membrane filter 24 to the demineralizer 150 in the next step.

  One end of an introduction pipe 40 is connected to a side portion of the primary chamber 22 formed in the filtration tower 20 through an introduction port 42. The other end of the introduction pipe 40 is connected to the antifouling agent dispersion tank 50. Thereby, the water in which the film surface contamination preventive agent stored in the contamination preventing agent dispersion tank 50 is dispersed can be introduced into the primary chamber 22 through the introduction pipe 40. At this time, in this embodiment, the anti-fouling agent dispersion tank 50 is disposed so as to be higher than the connection position between the primary chamber 22 and the introduction pipe 40, and the valve 41 provided on the introduction pipe 40 is provided. By opening, the water stored in the pollution inhibitor dispersion tank 50 is introduced into the primary chamber 22 by gravity.

As the film surface contamination inhibitor dispersed in water in the contamination inhibitor dispersion tank 50, iron oxide or iron hydroxide is used. As iron oxide , for example, α-Fe203, α-FeOOH, Fe304, or the like can be used. As the iron oxide and iron hydroxide, those generated in the power plant system (for example, amorphous, α-FeOOH, γ-FeOOH, Fe203, Fe304, etc.) can be used. By utilizing iron oxide or iron hydroxide generated in the power plant system, the amount of waste can be further reduced.

  The operation of coating the surface of the hollow fiber membrane filter 24 with the membrane surface contamination preventive agent is performed when the filtration device 10 is newly installed, when the hollow fiber membrane filter 24 is replaced, and all the water in the filtration tower 20 is drained. This is performed when the filtration device 10 is restarted at the time of inspection or at the time of cleaning the hollow fiber membrane filter 24 due to an increase in differential pressure. Specifically, first, the valve 31 a of the regeneration water inflow pipe 31 is opened, and about half of the water is filled in the primary chamber 22 of the filtration tower 20. Alternatively, in a state where water remains in the filtration tower 20 in advance, the valve 27a is opened and drained from the drain pipe 27 so that the water level in the primary chamber 22 becomes about half. Next, the valve 31a of the regeneration water inflow pipe 31 or the valve 27a of the drain pipe 27 is closed, the valve 41 of the introduction pipe 40 is opened, and water in which the membrane surface contamination inhibitor is dispersed is introduced. At this time, according to the present embodiment, the pollution inhibitor dispersion tank 50 is disposed at a higher position than the connection position between the introduction pipe 40 and the primary chamber 22 of the filtration tower 20, so the valve 41 is opened. Only water in which the film surface contamination preventive agent is dispersed by gravity is introduced into the primary chamber 22. When a predetermined amount of water in which the membrane surface contamination inhibitor is dispersed is introduced, the valve 41 is closed, the valve 28a of the compressed air introduction pipe 28 connected to the lower part of the filtration tower 20 is opened, and compressed air is introduced. Scrub. As a result, the membrane surface contamination preventive agent is uniformly agitated, and the membrane surface contamination preventive agent adheres almost evenly to the membrane surface of the hollow fiber membrane filter 24 immediately after the water filling operation, preventing the membrane surface contamination on the membrane surface. A coating of agent is formed.

If such a preparation is made, the valve 25a of the inflow pipe 25 and the valve 26a of the outflow pipe 26 are opened, and the operation of the filtration device 10 is started. The treated water flowing from the inflow pipe 25 passes from the outside to the inside of the hollow fiber membrane filter 24. At this time, suspended substances such as iron oxide particles contained in the treated water prevent the above-described membrane surface contamination. Captured by coating of agent. The treated water that has been filtered through the inside of the hollow fiber membrane filter 24 flows into the secondary chamber 23, and further passes through the outflow pipe 26 and is sent to the demineralizer 150 in the next step. If the differential pressure has increased by continuing the filtration process, the valves 25a and 26a are closed, the valve 28a of the compressed air introduction pipe 28 for cleaning and the valve 30a of the vent pipe 30 are opened, and compressed air is supplied. Introduce and clean. The hollow fiber membrane filter 24 is vibrated by the compressed air, and the membrane surface contamination preventive agent is peeled off. Suspended substances captured by the coating film of the membrane surface contamination preventive agent are removed together when the membrane surface contamination preventing agent is peeled off, so that the suspension remaining on the membrane surface of the hollow fiber membrane filter 24 is removed. There is very little material and the initial differential pressure does not increase with each wash.

  In order to restart the operation after washing, as described above, the valve 41 is opened, water in which the membrane surface contamination inhibitor is dispersed is introduced from the contamination inhibitor dispersion tank 50, and the membrane of the hollow fiber membrane filter 24 is again introduced. A film of a film surface contamination inhibitor is formed on the surface.

  According to this embodiment, since the water in which the membrane surface contamination preventive agent is dispersed is introduced into the primary chamber 22 simply by opening the valve 41, it is not necessary to use a dedicated pump, and the cost is reduced accordingly. Thus, it is possible to provide the filtration device 10 capable of forming a membrane surface antifouling agent film on the surface of the hollow fiber membrane filter 24.

  In the above-described embodiment, the introduction pipe 40 for introducing the film surface contamination preventing agent is directly connected to the primary chamber 22 of the filtration tower 20 via the introduction port 42. A branch port 30b may be provided in the connected vent pipe 30, and the introduction pipe 40 may be connected to the branch port 30b. Moreover, in the said embodiment, although the pollution inhibitor dispersion tank 50 is connected to the other end of the introduction pipe 40, such a dedicated water tank (pollution prevention agent dispersion tank 50) is not provided, for example, a funnel, for example. It is also possible to temporarily connect a water-like device to the other end of the introduction tube 40 and introduce the water in which the separately prepared membrane surface contamination inhibitor is dispersed through the funnel-like device. Of course, also in this case, the funnel-shaped instrument is arranged at a higher position than the connection position between the introduction tube 40 and the filtration tower 20 and is introduced by using gravity.

  Further, in the above description, after performing the coating operation of the membrane surface of the hollow fiber membrane filter 24 with the membrane surface contamination inhibitor, the operation is switched to the normal operation while the introduction pipe 40 is connected. It is preferable to switch to the normal operation after removing the introduction pipe 40 and closing the introduction opening 42, or when the branch pipe 30b is closed when connected to the branch opening 30b of the vent pipe 30.

Drawing 1 is a figure showing an example of the water treatment system of the power plant using the filtration device concerning one embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic structure of the filtration device according to the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Filtration apparatus 20 Filtration tower 22 Primary chamber 23 Secondary chamber 24 Hollow fiber membrane filter 25 Inflow pipe 26 Outflow pipe 40 Introduction pipe 50 Antifouling agent dispersion tank

Claims (5)

Prior to the start of the filtration treatment, iron oxide or hydroxide as a membrane surface contamination inhibitor is previously placed on the filtration membrane surface of the filtration filter for capturing suspended substances in the water to be treated, which is disposed in the primary chamber of the filtration tower. A method of coating a filtration filter for attaching iron,
The membrane surface contamination inhibitor is introduced into the primary chamber of the filtration tower using gravity, and then scrubbed by introducing compressed air into the primary chamber, and the membrane surface contamination on the filtration membrane surface of the filtration filter. A method for coating a filtration filter, comprising attaching an inhibitor. The method for coating a filtration filter according to claim 1, wherein the compressed air is scrubbed by being introduced from a compressed air introduction pipe for cleaning connected to the primary chamber.   Gravity of water containing the membrane surface antifouling agent held in the antifouling agent dispersion tank installed at a location higher than the connection position of the introduction pipe connected to the primary chamber of the filtration tower through the introduction pipe. The filtration filter coating method according to claim 1, wherein the filtration filter is introduced into a primary chamber of the filtration tower by using a filter.   The method for coating a filtration filter according to claim 1 or 2, wherein the filtration filter is a hollow fiber membrane filter.   The said filtration filter is installed for the condensate treatment of a power plant, The coating method of the filtration filter of any one of Claims 1-4 characterized by the above-mentioned.

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