JPS5876117A - Precoated filtering type water treating system - Google Patents

Abstract

PURPOSE:To effectively carry out the prolongation of the life of a filter aid, in the condensed water filtering and desalting vessel of an atomic power plant, by providing a precoating tank and a precoating pump to precoat of the filter aid prior to water sampling and during water sampling separately. CONSTITUTION:A powdery ion exchange resin as a filter aid is mixed with water by a stirrer 8 in a precoating tank 8 to be formed into a slurry and this slurry is sent into a filtering and desalting vessel 6 by a precoating pump 11. A precoated layer is formed on the surface of an element in the filtering and desalting vessel 6 from the filter aid in the slurry sent into said vessel 6 and permeated water is returned to the precoating tank 8. When water in the tank 8 becomes transparent, condensed water 5 is sent to the filtering and desalting vessel 6 through a change-over valve 15 by a pump to start the purification thereof. In the next step, the filter aid and water are mixed by a stirrer 9 in a precoating tank 10 during sending water to be formed into a slurry and the resulting slurry is sent into the filtering and desalting vessel 6 during the purification of condensed water by a precoating pump 12 to form another precoated layer on the precoated layer on the element 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glycofiltration type water treatment system, and more particularly to a precoated filtration type water treatment system suitable for use in condensate purification at a nuclear power plant.

Figure 1 shows a typical example of a conventional condensate purification system for a nuclear power plant. After the steam 2 generated by the atom P1 rotates the steam turbine 3 and generates electricity.

Condensate water is supplied to condensate 5 by condenser 4. Condensate contains solid and ionic impurities (mainly iron), which must be removed to improve the safety and reliability of power plants. The filtration demineralizer 6 and the demineralizer 7 are devices for removing impurities, and in the filtration demineralizer 6i, a plurality of cylindrical elements are precoated with powdered ion exchange resin to particularly filter solid matter.

The demineralizer 7 is filled with granular ion exchange resin and is intended to remove ionic impurities. A current problem in this system is that the filter aid in the filtration demineralizer 6, that is, the powdered ion exchange resin has a short lifespan. Due to the short filtration life, a large amount of filter aid waste is generated, and since it contains radioactive materials, it is difficult to process and dispose of it. There are two main countermeasures: one is the development of a method to extend the life of the filtration, and the other is the reuse of filter aids. To devise an effective long-life filtration method for extending the life of filter aids. The long-life filtration method is the second
As shown in the figure, the pre-coat operation is performed again during water sampling, which lengthens the internal filtration time (the portion where the filtration differential pressure ΔP rises slowly at the beginning of operation) and has the effect of increasing the filtration life. be.

An object of the present invention is to provide a Glyco-IJ' filtration type water treatment system that utilizes a long-life filtration system and can perform good condensate purification.

In order to adopt the long-life method that we have developed, we devised a solution by adding a pre-coat tank and a pre-coat pump to the conventional Precor filtration water treatment system.

An embodiment of the present invention will be described based on FIG.

The filter aid is mixed with water in the precoat tank 8 by an agitator 9 to form a slurry. Slurry is precoat pump 1
1 and sent to a filtration demineralizer 6. There are generally a plurality of filtration demineralizers 6, each having a plurality of elements 13 inside. The filter aid in the slurry fed into the filter demineralizer 6 forms a layer on the surface of the element 13. This is the precoat operation. The water that has passed through the element 13 returns to the precoat tank 8 and the suction side of the precoat pump 11 for circulation. When the water in the pre-coating tank 8 becomes clear, the pre-coating operation is completed. The precoat operation is often performed individually for each of the plurality of filtration demineralizers 6.

When the precoat operation is completed, the condensate 5 is sent to the filtration demineralizer 6 by the condensate pump 7, and condensate purification is started. The water from which impurities in the condensate have been removed becomes treated water 14 and is sent to the subsequent process. The flow of water is switched by a switching pulp 15.

Next, in the pre-coat tank 10, the filter aid and water are mixed with the stirrer 9 to create a slurry 1, and the slurry is sent with the pre-coat pump 12 to the filtration demineralizer 6 which is in the process of purifying condensate. By this operation, a suspension precoat layer is formed on the precoat layer of the element 13.

The filtration type water treatment system according to the present invention enables effective use of the long-life filtration method devised by us, and has the effect of extending the life of the filter aid.

According to the present invention, since impurities in condensate water can be removed for a long time using a certain filter aid, there is an effect of reducing waste of the filter aid. Therefore, the cost of purchasing filter aids and the cost of processing and disposing waste materials are reduced.

[Brief explanation of the drawing]

Figure 1 is a route map showing a conventional condensate purification system, Figure 2 is a diagram explaining a long-life filtration system, and Figure 3 is a diagram showing a long-life filtration system. 1-1 Stock % formula % Hitachi, Ltd., 5-5 Marunouchi, Chiyoda-ku, Tokyo 0 Inventor Makoto Numazaki - 3-1-1 Saiwaimachi, Hitachi City Stock % formula %

Claims (1)

[Claims] 1. Precoating is performed separately before and during water sampling. For pre-coating of filter aids in sampled water. A pre-coat filtration water treatment system characterized by the addition of a pre-coat tank and a Glycode pump. 2. The precoat filtration type water treatment system according to claim 1, wherein the filter element of the precoat type water treatment system is made of metal having micropores.