JPS61157390A - Desalting apparatus - Google Patents

Abstract

PURPOSE:To make it possible to effectively remove clad, by providing a cation exchange resin with a small particle size above a mixed bed. CONSTITUTION:A desalting apparatus 101 consists of a container main body 102, the mixed bed 103 received in the container main body 102 and the cation exchange resin 121 arranged above the mixed bed 103. The mixed bed 103 is constituted by mixing a cation exchange resin 104 and anion exchange resin 105. By this method, clad can be adsorbed and removed effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a desalination apparatus for desalinating water to be treated, for example, condensate of a primary cooling system of a nuclear power plant.

[Technical background of the invention]

A conventional example will be explained with reference to FIG. FIG. 1 is a system diagram of a desalination plant that desalinates condensate in the primary cooling system of a nuclear power plant. The reference numeral in the figure indicates a desalination device, and this desalination device is composed of a container body 2 and a mixing bed 3 installed within this container body 2. This mixed bed 3 has a configuration in which a cation exchange resin 4 and an anion exchange resin 5 are mixed. The condensate is then introduced into the container body 2 via the condensate introduction pipe 6, and is purified by passing through the mixed bed 3 to remove insoluble and dissolved components. The purified condensate is transferred from the condensate outlet pipe 7.

In the above configuration, the mixed bed 3 is regenerated by the following operation. That is, the mixed bed 3 in the container body 2 of the desalination apparatus is introduced into a cation exchange resin regeneration tank (hereinafter referred to as CRT) 9 via an ion exchange resin extraction pipe 8. After the introduction, water is fed from below the CRT 9 through the water introduction pipe 10B to float the ion exchange resin. By this operation, the cation exchange resin 4 and anion exchange resin 5 that constituted the mixed bed 3 are separated into upper and lower parts due to the difference in their specific gravity. That is, the anion exchange resin 5 with a light specific gravity is separated into the upper side, and the cation exchange resin 4 with a heavy specific gravity is separated into the lower side. The anion exchange resin 5 is introduced into an anion exchange resin regeneration tank (hereinafter referred to as ART) 12 via an anion exchange resin extraction pipe 1 and is regenerated. - The men's bath ion exchange resin 4 is regenerated in the cation exchange resin regeneration tank 9. These regenerated cation exchange resin 4 and anion exchange resin 5 are transferred to a mixing tank (hereinafter referred to as R8T) 15 through a regenerated cation exchange resin extraction pipe 13 and a regenerated anion exchange resin extraction pipe 14, respectively.
After being mixed, the regenerated mixed ion exchange resin is supplied into the container main body 2 through the extraction pipe 16 and then mixed again into the mixing bed 3.
It is a configuration that forms a.

[Problems with background technology]

In the above configuration, cations in the condensate are adsorbed on the cation exchange resin 4, and anions are adsorbed on the anion exchange resin 5. Insoluble components (hereinafter referred to as Kura) in ion exchange resins such as cation exchange resin 4 and anion exchange resin 5 mentioned above
It has a removal ability (referred to as "do"). This crud is mainly composed of iron oxides, the resin and the intergranular crud loosely trapped between the resins, and the resin-adhered iron that is removed by chemical regeneration with sulfuric acid (H2SO4) and sodium hydroxide (NaOH). Removal of these cruds is extremely important in maintaining the health of nuclear power plants, and there has been a need to improve the removal rate of these cruds.

[Purpose of the invention]

The present invention has been made based on the above points, and an object of the present invention is to provide a desalination apparatus capable of effectively removing not only dissolved components but also insoluble components, that is, crud.

[Summary of the invention]

That is, the desalination apparatus according to the present invention includes a container body and a mixed bed made of a cation exchange resin and an anion exchange resin, which is provided inside the container body, and demineralizes water by flowing the water to be treated through this mixed bed. In the desalting equipment for salt treatment, a cation exchange resin layer with small particle size is provided above the mixed bed. 11 [Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 2 to 5. Before going into the explanation of the desalination apparatus according to this example, let us explain the relationship between the depth from the resin surface layer and the amount of intergranular cladding iron, and the relationship between cation exchange resin and anion exchange resin using Figures 2 to 4. The comparison between the following and the relationship between the crud removal rate and the average resin particle size will be explained.

FIG. 2 is a diagram showing the change in the amount of intergranular cladding iron with respect to the depth from the resin surface layer, with the horizontal axis representing the amount of intergranular cladding iron and the vertical axis representing the depth from the resin surface layer. In the figure, the ○ mark is the value at the center of the desalination device container body, the Δ mark is the value at a position 600 m in the radial direction from the center, and the 0 mark is the value at a position 1 c 1100 m in the radial direction from the center (approximately the outermost stomach) The values and ・marks indicate the average values, respectively. As is clear from FIG. 2, a larger amount of intergranular cladding iron is captured as it approaches the resin surface layer. That is, the closer to the resin surface layer, the more effectively the amount of intergranular cladding iron can be captured.

In addition, similar tests were conducted for anion exchange resins and cation exchange resins, and the results shown in Figure 3 were obtained. The diagram indicated by symbol (B) is a diagram showing the change in the amount of deposited iron due to cation exchange resin, and the diagram indicated by symbols (C) and ) represents the average of the anion-exchange resin-attached steel tower inner wire and the cation-exchange resin-attached steel tower inner wire average, respectively.

As is clear from Figure 3, cation exchange resins adhere more easily than anion exchange resins.

It can be seen that the resin has a large amount of iron and has excellent cladding adhesion performance (more than 10 times that of anionic resin).

Next, the relationship between the average resin particle size and crud removal rate will be explained with reference to FIG. FIG. 4 is a diagram in which the horizontal axis represents the average resin particle diameter, the vertical axis represents the crud removal rate, and the change in crud removal rate depending on the average resin particle size. Symbol (g) in the figure)
The diagram shown with the symbol ( ) shows the case of a new ion exchange resin, and the diagram shown with the symbol ( ) shows the case of an ion exchange resin in use.As is clear from this Figure 4, However, it can be seen that even with the ion exchange resin in use, the smaller the average resin particle size, the higher the removal rate of Kura and P. This is because the adsorption area can be increased by reducing the resin particle size. The particle size of the ion-exchange resin is distributed in the range of 300 to 1100 μm, and follows a roughly logarithmic average distribution.The gap when filled with such an ion-exchange resin is the average diameter of the cladding (approximately 2 μm). This indicates that crud removal by ion exchange resin is mainly done by adsorption rather than filtration, and as mentioned above, reducing the particle size and increasing the adsorption area increases the crud removal rate. It can be seen that it has an enhancing effect.

The desalination apparatus according to the present embodiment is designed to improve the crud removal rate by taking the above points into consideration, and will be described below with reference to FIG. 5. FIG. 5 is a system diagram showing a schematic configuration of a desalination plant incorporating the desalination apparatus according to this embodiment. The reference numeral 101 in the figure indicates desalination@I. This desalination apparatus storm is composed of a container body 102, a mixed bed 103 housed within this container body 102, and a cation exchange resin layer 121 with a small particle size installed above this mixed bed 103. The mixed bed 103 has a configuration in which a cation exchange resin 104 and an anion exchange resin 105 are mixed.

That is, the configuration is such that a cation exchange resin with excellent crud removal performance is placed in the form of small particles above the container body 102 (resin surface layer position) where crud can be effectively removed.

Therefore, it is possible to effectively adsorb and remove the above-mentioned cycra and de, and it is also possible to effectively remove not only dissolved components but also insoluble components (crud), which improves the reliability of the device. It is extremely effective in improving the safety of nuclear power plants.

Next, a mixed bed 103 and a small particle size cation exchange resin layer 12
1 will be explained.

In other words, during normal operation, the condensate is
Condensate is introduced into the vessel body 102 of the desalination apparatus 101, passes through the small particle size cation exchange resin layer 121 and the mixed bed IOS, and is discharged via the condensate outlet pipe 107. When the pressure difference between the inlet and outlet of the desalination equipment 101 reaches a predetermined value (for example, 3.5 kg/cnr"G) or when a predetermined amount of condensate has passed through, the introduction of condensate is stopped. Then, the operation for regenerating the small particle diameter cation exchange resin layer 121 and the mixed bed 103 begins.First, water is fed through the water introduction pipe 110A to float the ion exchange resin in the container body 102, and at the same time, compressed air is introduced from the top of the container body 102. (about 3-5 Yu/α2)
The floating ion exchange resin is extracted through the ion exchange resin extraction pipe 108 and introduced into the CRT J 09. Then, the CRT 10 is connected to the CRT 10 via the water introduction pipe 110B.
9 and float the ion exchange resin inside the CRT 109.

As a result, the anion exchange resin and the cation exchange resin are separated based on their specific gravity difference, and the anion exchange resin 105 with a light specific gravity is collected in the upper part of the CRT 109, and the cation exchange resin 104 with a heavy specific gravity is collected in the lower part. It will be done. At that time, in the case of anion exchange resin 105, cation exchange resin 10
In the case of No. 4 as well, particles with small diameters are collected in the upper part and particles with coarse diameters are collected in the lower part. Next, the anion exchange resin 105 in the upper layer is introduced into the ART 112 via the anion exchange resin extraction pipe 111 and regenerated. At the same time K
The cation exchange resin 104 is regenerated in the CRT log. This regeneration is so-called chemical regeneration, and 5~
This is carried out by introducing 10 g of sulfuric acid (H2S04) and 4 to 10 g of loess soda (NaOH). The recycled anion exchange resin 105 and the cation exchange resin 104 except for the small particle size portion at the upper end are passed through the recycled anion exchange resin extraction pipe 114 and the recycled cation exchange resin extraction pipe 113. and is introduced into R8T 115. This R8T 115 performs stirring and mixing by supplying water and compressed air from the water introduction pipe 110D. The agitated ion exchange resin is then passed through the recycled mixed ion exchange resin extraction pipe 116 to the container body 102 of the desalination apparatus 101.
103 to form a mixed bed 103. Next, the small particle diameter portion of the upper end portion of the cation exchange resin remaining in the CRT 109 is introduced into the upper part of the mixed bed 103 through the recycled cation exchange resin extraction pipe 122 to ionize the small particle diameter cations. An exchange resin layer 121 is formed. This completes playback.

In other words, when the ion exchange resin used in the CRT 109 is separated into the anion exchange resin 105 and the cation exchange resin 104, we focus on the fact that the particles with smaller particle sizes are at the upper K. When drawing and mixing the ion exchange resin 104 after chemical regeneration, the cation exchange resin 104 is pulled out from below, that is, in order from the larger particle size, and the small particle size portion at the upper end is temporarily transferred to the CRT 70.
Leave it within 9. After the mixed bed 103 is formed, it is pulled out to form a small particle size cation exchange resin layer 121 above the mixed bed 103. Therefore, the ion exchange resin can be regenerated by a simple operation.

〔Effect of the invention〕

As described in detail above, the desalination apparatus according to the present invention includes a container body and a mixed bed made of a cation exchange resin and an anion exchange resin, which is provided inside the container body, and in which the water to be treated is placed in the mixed bed. In this desalting apparatus, a cation exchange resin layer with a small particle size is provided above the mixed bed.

Therefore, it is possible to effectively remove not only dissolved components but also undissolved components, that is, crud, which greatly improves the reliability of the device, and also improves safety when applied to nuclear power plants. It is extremely effective in achieving this goal.

[Brief Description of the Drawings] Fig. 1 is a system diagram of a desalination plant incorporating a conventional desalination device, Figs. 2 to 5 are diagrams showing an embodiment of the present invention, and Fig. Figure 3 shows the relationship between intergranular cracks and iron content and the depth from the resin surface layer. Figure 4 shows the relationship between the amount of iron and the depth from the resin surface layer for anion exchange resin and cation exchange resin, and Figure 4 shows the relationship between the average resin particle size and the removal rate of cracks and cracks. , FIG. 5 is a system diagram of a desalination plant incorporating the desalination apparatus of this embodiment. 101... Desalination device, 102... Container body, 103
...Mixed bed, 104...Cation exchange resin, 105
...Anion exchange resin, 121...Small particle diameter cation exchange resin layer.

Claims (1)

[Claims] comprising a container body and a mixed bed provided within the container body and comprising a cation exchange resin and an anion exchange resin,
A desalination apparatus that desalinates water by flowing it through the mixed bed, characterized in that a cation exchange resin layer with a small particle size is provided above the mixed bed.