JPH05188184A - Resin regenerating device of condensing and desalting apparatus - Google Patents

Abstract

PURPOSE:To decrease the organic impurities eluted from the ion exchange resin in a condensing and desalting tower by using the gas (nitrogen gas, inactive gas or the like), which does not contain oxygen in backwash regeneration. CONSTITUTION:Solid matter is attached to the layer of a granular ion exchange resin 1 filled in a condensing and desalting tower 2. The resin, on which pressure difference between an inlet port and an outlet port exceeds the specified value, is sent into a cation-exchange-resin regenerating tower 6. Nitrogen gas is injected from a nitrogen cylinder 15 into the lower parts of the regenerating tower 6. The resin 1 is agitated with the nitrogen gas and water. The solid matter, which is separated from the resin 1, is drain from the bottom of the regenerating tower 6 and discharged through an overflow pipe 9 together with backwash water. The resin is backwashed and separated into cation and anion exchange resins. The separated respective resins are sent into the regenerating towers 6 and 7 and backwashed and regenerated with the nitrogen gas and the water. The regenerated resin is sent into a resin storing tank 8 and mixed in the tank. The resin in the mixed state is returned into the desalting tower 2. The gas, which does not contain oxygen, is used in backwash and regeneration. Thus, the elution of the organic material from the ion exchange resin is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensate demineralizer installed in a condensate purification system of a nuclear power plant, and particularly to a reactor for organic impurities eluted from an ion exchange resin in a condensate demineralization tower. The present invention relates to a resin regenerator for a condensate demineralizer that reduces inflow into the interior.

[0002]

2. Description of the Related Art Generally, reactor water used in a nuclear power plant is required to be kept in high-purity water, so a condensate desalination device for removing solid matter (clad) and soluble impurities is installed is doing.

FIG. 4 shows a condensate demineralizer provided in a conventional condensate purification system of a nuclear power plant. This apparatus comprises a plurality of condensate demineralization towers 2 filled with a granular ion exchange resin 1.
And a resin strainer 3 installed in series in the condensate demineralization tower 2 and a regenerator 20 existing for regenerating the granular ion exchange resin 1 in the condensate demineralization tower 2.

Purification is performed by capturing solid matters (clads) and soluble impurities by a layer of the granular ion exchange resin 1 filled in the condensate demineralization tower 2. When the solid matter adheres to the granular ion exchange resin 1 and the pressure difference between the inlet and the outlet exceeds a prescribed value, the condensate demineralization tower 2 is disconnected from the condensate system by stopping the inflow and outflow of the condensate.

The granular ion exchange resin 1 in the condensate demineralization tower 2 separated from the condensate system is guided from the lower resin outlet pipe 4 to the resin transfer pipe 5 and first transferred to the cation exchange resin regeneration tower 6. Air is injected into the lower part of the cation exchange resin regeneration tower 6 from the internal compressed air system 13, the granular ion exchange resin 1 is stirred with water and air, and the solid matter separated from the granular ion exchange resin 1 is released into water. Let

The solid substance released in water is put on backwash water from the lower part of the cation exchange resin regeneration tower 6 and discharged from the overflow pipe 9, and the ion exchange resin is mixed with the cation exchange resin and the anion exchange resin. Backwash and separate. After the separation, the anion exchange resin is transferred to the anion exchange resin regeneration tower 7 where it is backwashed, and the cation exchange resin is backwashed and regenerated in the cation exchange resin regeneration tower 6.

The above-mentioned "backwash regeneration" means that when solid matter adheres to the ion exchange resin of the condensate demineralization tower and the differential pressure between the inlet and outlet exceeds a specified value, water and air are regenerated by the regenerator. The process of backwashing and cleaning is called, and the performance of the ion exchange resin can be restored.

When the backwash regeneration is completed, the regenerated resin is transferred to the resin storage tank 8 through the resin transfer pipes 10 and 11, and mixed there, and the granular ion-exchange resin in the mixed state is reconstituted through the resin transfer pipe 12. Return to the desalting tower 2. As mentioned above,
In the conventional backwash regeneration, a method of injecting air and water to remove the solid matter adhering to the ion exchange resin has been carried out.

[0009]

However, in the above-mentioned backwash regeneration method, the oxygen in the air to be injected comes into contact with the ion exchange resin, which accelerates the deterioration of the ion exchange resin and elutes the organic impurities. Has become.

Since the organic impurities are hardly removed and flow into the nuclear reactor, they are decomposed by being exposed to high temperature and high pressure conditions and radiation in the reactor, and various impurities are produced. recent years,
At the time of plant startup, the deterioration of reactor water quality due to the impurities has become a problem.

The present invention has been made to solve the above problems, and provides a resin regenerator for a condensate demineralizer that can reduce the elution of organic impurities from the ion exchange resin in the condensate demineralizer. The purpose is to do.

[0012]

The present invention relates to a condensate demineralizer provided in a condensate purification system facility of a nuclear power plant, and a cation exchange resin regeneration tower through a resin transfer pipe to the condensate demineralizer tower. And an anion exchange resin regeneration tower are connected, and a gas supply system containing no oxygen at the time of backwash regeneration is connected to each of the cation exchange resin regeneration tower and the anion exchange resin regeneration tower.

[0013]

[Function] The resin regenerator of this condensate demineralizer uses a gas that does not contain oxygen in order to prevent deterioration of the ion exchange resin in the condensate demineralizer due to oxygen in the air during backwash regeneration. By providing a different ion exchange resin regeneration means, it has a function of preventing the inflow of organic impurities eluted from the ion exchange resin in the condensate desalination tower into the reactor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a resin regenerating apparatus for a condensate dewatering device according to the present invention will be described with reference to FIG.

In FIG. 1, a condensate demineralization tower 2 filled with a granular ion exchange resin 1 and a resin strainer are connected in series to the condensate demineralization tower 2. In addition, the condensate desalination tower 21
A regeneration device 20 for regenerating the granular ion exchange resin 1 is connected to the lower resin outlet pipe 4 of the above through a resin transfer pipe 5. The regenerator 20 comprises a cation exchange resin regeneration tower 6 and an anion exchange resin regeneration tower 7 connected to a resin storage tank 8 via resin transfer pipes 10 and 11, respectively.

An overflow pipe 9 is provided above the cation exchange resin regeneration tower 6 and the anion exchange resin regeneration tower 7, respectively.
In addition, the lower part is connected to a nitrogen cylinder 15 via a pipe 14 as a supply system of a gas containing no oxygen during backwash regeneration. The lower part of the resin storage tank 8 is connected to the upper part of the condensate demineralization tower 2 via a resin transfer pipe 12.

In the resin regenerator of the condensate demineralizer of the above construction, however, the solid matter adheres to the layer of the granular ion exchange resin 1 filled in the condensate demineralizer 2 and the space between the inlet and the outlet. The granular ion exchange resin 1 in the condensate demineralization tower 2 whose differential pressure has exceeded the regulation is separated from the condensate system, and the lower resin outlet pipe 4
Is introduced into the resin transfer pipe 5, and is first transferred to the cation exchange resin regeneration tower 6.

A nitrogen cylinder is provided under the cation exchange resin regeneration tower 6 and the anion exchange resin regeneration tower 7 through a pipe 14.
Inject nitrogen gas from 15. The granular ion exchange resin 1 is agitated with nitrogen gas and water to release the solid matter separated from the granular ion exchange resin 1 into water. The solid matter released in water is put on backwash water from the lower part of the cation exchange resin regeneration tower 6 and discharged from the overflow pipe 9, and the ion exchange resin is backwashed into a cation exchange resin and an anion exchange resin. To separate.

After the separation, the anion exchange resin is transferred to the anion exchange resin regeneration tower 7, and the cation exchange resin is backwashed and regenerated with nitrogen gas and water in the cation exchange resin regeneration tower 6. When the backwash regeneration is completed, the regenerated resin is transferred to the resin storage tank 8 through the resin transfer pipes 10 and 11, and mixed there, and the granular ion exchange resin in the mixed state is passed through the resin transfer pipe 12 to the condensate demineralization tower. Return to 2.

In addition to the means for connecting the nitrogen cylinder 15 as the oxygen-free gas supply system to each of the ion exchange resin regeneration towers 6 and 7 through the pipe 14, the second embodiment shown in FIG. As shown, it is possible to install a pipe 17 from the high pressure nitrogen gas supply system 16 and inject nitrogen into the cation exchange resin regeneration tower 6 and the anion exchange resin regeneration tower 7. Also,
It is also possible to use an inert gas instead of nitrogen.

In FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description of the overlapping parts will be omitted. As the usefulness of substituting nitrogen with air, as shown in FIG. 3, the result is obtained that nitrogen-saturated water produces less organic impurities from the ion-exchange resin than air-saturated water.

By performing the above operation,
Since the active gas does not come into contact with the ion exchange resin, deterioration of the ion exchange resin can be prevented. In the embodiment of the present invention, in the resin regenerator of the condensate demineralizer,
Although an example in which nitrogen gas is used as a means for backwash regeneration is shown, an inert gas can also be applied to this resin regeneration apparatus.

[0023]

EFFECTS OF THE INVENTION According to the present invention, by using a gas containing no oxygen during backwash regeneration, it is possible to reduce organic impurities eluted from the ion exchange resin in the condensate demineralization tower, and Can be prevented and the water quality of the reactor can be maintained at high purity. As a result, the soundness of the reactor structural material can be maintained, and the reliability of the nuclear power plant can be improved and the life can be extended.

[Brief description of drawings]

FIG. 1 is a system diagram schematically showing a first embodiment of a regenerator for a condensate demineralizer according to the present invention.

FIG. 2 is a system diagram schematically showing a second embodiment of a regenerator for a condensate desalination apparatus according to the present invention.

FIG. 3 is a distribution chart showing the amount of organic carbon (TOC) eluted from the ion exchange resin by dissolved oxygen.

FIG. 4 is a system diagram schematically showing a regenerator of a conventional condensate demineralizer.

[Explanation of symbols]

1 ... Ion exchange resin, 2 ... Condensate demineralization tower, 3 ... Resin strainer, 4 ... Lower resin outlet pipe, 6 ... Cation exchange resin regeneration tower, 7 ... Anion exchange resin regeneration tower, 8 ... Resin storage tank, 9 …
Overflow pipe, 13… Compressed air system for internal use, 14… Piping,
15 ... Nitrogen cylinder, 16 ... High pressure nitrogen gas supply system, 20 ... Regeneration device, 5, 10, 11, 12 ... Resin transfer piping, 14, 17 ... Piping.

Claims (1)

[Claims] 1. A condensate desalination apparatus provided in a condensate purification system of a nuclear power plant, wherein a cation exchange resin regeneration tower and an anion exchange resin regeneration tower are provided in the condensate desalination tower via a resin transfer pipe. And a cation-exchange resin regeneration tower and an anion-exchange resin regeneration tower, each of which is connected with a gas-free gas supply system during backwash regeneration. apparatus.