JPH08313692A - Recovery method and device for ion exchange resin in demineralizing device - Google Patents

Abstract

PURPOSE: To ensure the stability of water quality by enabling exhausting high TOC out of system immediately after water supply and preventing the oxidation degradation of ion exchange resin. CONSTITUTION: In a condensate demineralizing device of a reactor power plant, particle ion exchange resin in a demineralizing tower is washed with warm demineralized water of the similar temperature to the condensate. By this, high total organic carbon (TOC) immediately after water supply in the demineralizing tower 20 is reduced. A warm water supplier 27 and warm water inlets 31, 32 and 33 for supplying demineralized water for washing and nitrogen supplier 36 for demineralization are connected to a cation exchange resin recovery tower 22 and anion exchange resin recovery tower 23. To the condensate inlet pipe 29 in the demineralizing tower 20, a condensate temperature meter 34 is provided. By this, sudden TOC elution immediately after temperature rise and TOC elution from the ion exchange resin due to contact to high oxygen solution water and oxidation degradation can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating an ion exchange resin in a desalting apparatus installed in a boiling water nuclear power plant and the apparatus therefor.

[0002]

2. Description of the Related Art In a boiling water nuclear power plant, the inside of the reactor must be kept clean. Therefore, the condensate flowing into the reactor from the condenser is purified by a desalination device to a high degree. After purification, it is used as cooling water for the reactor.

An example of a conventional nuclear power plant will be described with reference to FIG. In FIG. 3, steam generated in the reactor pressure vessel 1 is sent to a turbine 3 via a main steam pipe 2, and the turbine 3 is configured to start a generator 4 to generate power. The steam that has driven the turbine 3 is condensed in the condenser 5 and becomes condensed water.

Condensate is boosted by a low-pressure condensate pump 6, flows through an air extractor 7, is condensed by a gland steam condenser 8, and is installed in a condensate purification system. The impurities are removed by 10.

Condensate purified by the condensate filter 9 and the condensate demineralizer 10 is pressurized by a high pressure condensate pump 11 on the downstream side,
It is sent to the low-pressure heater 12 and heated, and then the water supply pump 13
And is further heated by the high-pressure heater 14 to supply water into the reactor pressure vessel 1 to cool a core (not shown).

The turbine bleed air 15 is condensed by the high-pressure heater 14 into a high-pressure heater drain, which is returned to the water supply system through the high-pressure drain tank 16 and the water supply system return pipe 18. Further, the low-pressure heater drain condensed by the low-pressure heater 12 is returned to the inlet of the condensate demineralizer 10 through the low-pressure drain tank 17 and the condensate system return pipe 19.

As shown in FIG. 4, the condensate demineralizer 10 is composed of a desalting tower 20. In the desalting tower 20, an ion exchange resin 21 is contained and a cation exchange resin and an anion exchange resin are contained. It is filled in a mixed state. When regenerating this ion exchange resin 21, first, the ion exchange resin 21 in the mixed state in the desalting tower 20 is transferred to the cation exchange resin regenerating tower 22, and the specific gravity difference between the cation exchange resin and the anion exchange resin is changed. Use and separate.

The separated anion exchange resin is transferred to the anion exchange resin regeneration tower 23. The sulfuric acid transferred from the sulfuric acid supply device 25 is diluted to a predetermined value by the sulfuric acid diluting device 24 and then supplied to the cation exchange resin regeneration tower 22. As a result, the cation exchange resin in the cation exchange resin regeneration tower is regenerated.

The caustic soda transferred from the caustic soda supply device 28 is heated by the hot water sent from the hot water supply device 27 having a temperature control function, diluted with the caustic soda diluting device 26, and then anion exchange resin regeneration tower 23. Is supplied to. As a result, the anion exchange resin in the anion exchange resin regeneration tower is regenerated.

The regenerated anion exchange resin is returned to the cation exchange resin regeneration tower 22, where it is subjected to final washing and mixing to perform a desalting tower.
Transferred to 20. Then, the desalination tower 20 introduces the condensate from the condensate inlet pipe 29, exchanges ions with the ion exchange resin 21, supplies the condensate to the condensate outlet pipe 30, and starts the condensate purification operation.

[0011]

The temperature of the condensate flowing into the condensate demineralizer 10 is from the condensate temperature of about 30 ° C to 40 ° C when the conventional heater drain is collected in the condenser 5. About 50
It becomes as high as ℃. The desalination tower 20 of the condensate demineralizer 10 described above,
Since the condensate temperature rises as described above because it has a granular ion exchange resin, the oxidative deterioration of the ion exchange resin is promoted, the TOC (total organic carbon) eluted from the resin matrix increases, and the outlet water quality increases. And worsen the water quality of the reactor water.

As shown in FIG. 5, the tendency has a tendency to show a steady value after a rapid increase in the elution amount immediately after the temperature rises with respect to the temperature change. Also, after regenerating the ion exchange resin,
The water supplied from the condensate storage tank is used as full water for the desalination tower.

The water for full water has a high dissolved oxygen concentration, the ion exchange resin is oxidatively deteriorated, and total organic carbon (TOC) is generated from the mother of the ion exchange resin.
There is a problem that deteriorates the water quality at the exit. As shown in FIG. 6, this tendency has a tendency that the higher the dissolved oxygen concentration is, the more the total organic carbon is eluted. In Fig. 6, the vertical axis is T
In OC, the horizontal axis is time, in the figure, ○ indicates highly dissolved oxygen water,
● indicates deaerated water (low dissolved oxygen).

The present invention has been made to solve the above problems, and suppresses the rapid TOC elution immediately after the temperature rise and the TOC elution from the ion exchange resin due to oxidative deterioration due to contact with highly dissolved oxygen water. (EN) A method for regenerating an ion exchange resin in a condensate demineralizer and a device therefor.

[0015]

According to the method of the present invention, an ion exchange resin in a desalination tower having an inlet pipe and an outlet pipe of water to be purified is transferred to a cation exchange resin regeneration tower and an anion exchange resin regeneration tower. Regenerated or backwashed, the regenerated or backwashed ion-exchange resin is returned to the desalting tower, and then de-aired water having a temperature equal to the temperature of the water to be purified is supplied to the desalting tower to perform the regeneration. Alternatively, the backwashed ion-exchange resin is washed with water at room temperature.

The apparatus of the present invention comprises a desalting tower having an inlet pipe for water to be purified filled with an ion exchange resin, a cation exchange resin regenerating tower connected to the desalting tower, and the cation exchange resin regenerating tower. A connected anion exchange resin regeneration tower, hot water inlet pipes respectively connected to the desalting tower, the cation exchange resin regeneration tower and the anion exchange resin regeneration tower, and a hot water supply device connected to the hot water inlet pipe, A degassing gas supply device connected to the cation exchange resin regeneration tower and the anion exchange resin regeneration tower.

[0017]

Function: The ion exchange resin in the desalting tower is transferred to the cation exchange resin regenerating tower. Then, it is separated into cation exchange resin and anion exchange resin in the cation exchange resin regeneration tower and regenerated or backwashed respectively, and the regenerated or backwashed ion exchange resin is returned to the desalting tower, and then temperature detection is performed. Then, the de-aired water having a temperature equal to the detected temperature of the water to be purified is supplied.

Here, the de-aired temperature water is obtained by bubbling by supplying hot water and nitrogen gas into the cation exchange resin regeneration tower and the anion exchange resin regeneration tower. The deionized water is introduced into the desalting tower to wash the ion exchange resin, and the warm water in the desalting tower containing TOC which is rapidly eluted from the ion exchange resin is discharged to the radioactive waste treatment system.

When the TOC elution reaches a steady value, the water to be purified is introduced, is ion-exchanged with an ion exchange resin, and flows out from the outlet pipe of the water to be purified. As a result, the high-concentration TOC water can be discharged by washing the de-ambient temperature water before passing the water, and the TOC concentration can be lowered during the water passing.

[0020]

EXAMPLE An example of a method for regenerating an ion exchange resin in a condensate demineralizer according to the present invention and an apparatus therefor will be described with reference to FIG. In FIG. 1, the same parts as those in FIG. 4 are denoted by the same reference numerals, and the treated water to be purified is, for example, condensate from a turbine.

In FIG. 1, an ion exchange resin 21 is filled in the desalting tower 20 which constitutes the condensate demineralizer. The ion exchange resin 21 is a mixture of a cation exchange resin and an anion exchange resin. A cation exchange resin regeneration tower 22, a condensate outlet pipe 30, and a drain outlet pipe 35 are connected to the lower portion of the desalting tower 20.

A condensate inlet pipe 29 and one end of a warm water inlet pipe 31 are connected to the upper portion of the desalination tower 20, and a condensate thermometer 34 is attached to the condensate inlet pipe 29. The cation exchange resin regeneration tower 29 has a lower end connected to the other end of the hot water inlet pipe 31, and an upper portion connected to the hot water inlet pipe 32. This hot water inlet pipe
A pipe branched from 32 is connected to the upper side surface of the desalination tower 20.

The cation exchange resin regeneration tower 22 has a pipe connected to the desalting tower 20 on the upper side surface and a pipe connected to the lower portion of the anion exchange resin regeneration tower 23, and an anion exchange resin on the middle side surface. A pipe connected to the upper side surface of the resin regeneration tower 23 and a pipe connected to the sulfuric acid diluting device 24 are connected. The sulfuric acid diluting device 24 is connected to the sulfuric acid supply device 25. Cation exchange resin regeneration tower
A pipe connected to, for example, a nitrogen supply device 36 as a degassing gas supply device is connected to the lower part of the column 22 and the anion exchange resin regeneration tower 23.

A hot water inlet pipe 33 is connected to the upper part of the anion exchange resin regeneration tower 23, and the hot water inlet pipe 33 is connected to the hot water supply device 27. The hot water supply device 27 is also connected to the caustic soda diluting device 26. The caustic soda diluting device 26 is connected to the lower portion of the anion exchange resin regeneration tower 23 by piping. The caustic soda diluting device 26 is connected to the caustic soda supplying device 28.

Next, the operation of the above embodiment will be described. In the ion exchange resin regenerating apparatus having the above structure, the ion exchange resin 21 in the desalting tower 20 is transferred to the cation exchange resin regenerating tower 22. The ion exchange resin regenerated or backwashed from the cation exchange resin regeneration tower 22 is returned to the desalting tower 20 to be in a standby state.

Hot water is introduced from the hot water supply device 27 into the cation exchange resin regeneration tower 22 through the hot water inlet pipe 32, and further nitrogen is supplied from the nitrogen supply device 36 to de-air temperature water by bubbling. Desaturated water is introduced into the desalination tower 20 through a pipe 31. A non-oxidizing neutral gas can be used instead of nitrogen.

The temperature of the dehumidified water is adjusted by the hot water supply device 27 so that the dehumidified water has a temperature equal to the condensate water detected by the condensate thermometer 34. TOC that introduces de-temperatureed water into the desalting tower 20 and rapidly elutes from the ion exchange resin 21
The water in the desalination tower 20 including is discharged to the radioactive waste treatment system through the drain outlet pipe 35.

When the TOC elution reaches a steady value, condensate is introduced from the condensate inlet pipe 29, ion-exchanged with the ion-exchange resin 21, and flows out from the condensate outlet pipe 30. As a result, as shown in FIG. 2, high-concentration TOC water (part a in the figure) is discharged to the outside of the system by washing the room temperature water before passing water, and the T
The OC concentration can be lowered.

FIG. 2 is a graph showing the TOC elution behavior according to this example. The vertical axis shows the temperature (° C.) and the TOC concentration at the desalting tower outlet (ppb), and the horizontal axis shows regeneration, washing with warm water, and water passage. Taking steps.

The present invention is not limited to the above-mentioned embodiment. (1) In the case of directly supplying the deionized water to the cation exchange resin regeneration tower 22 to wash the deionized water, (2) the cation When directly supplying to the exchange resin regeneration tower 22 and the anion exchange resin regeneration tower 23 for washing with de-temperatureed water, (3) desalting tower 20
It can also be applied to the case where the de-aired water is directly supplied to and used as storage water.

The embodiments of the present invention are summarized as follows. (1) In the desalination equipment, the ion exchange resin in the desalting tower is washed with degassed hot water at a temperature similar to that of the water to be purified, so that the high TOC (total Regeneration method characterized by reducing organic carbon).

(2) The demineralization tower is characterized by being provided with a hot water supply device and a degassing gas supply device for supplying degassing water for cleaning at a temperature similar to that of the water to be purified. (3) The cation exchange resin regeneration tower is characterized by being provided with a hot water supply device and a degassing gas supply device for supplying degassing water for cleaning having a temperature similar to that of the water to be purified.

(4) Hot water supply device and degassing gas supply device for supplying deionized water for cleaning having a temperature similar to that of the water to be purified to the cation exchange resin regeneration tower and the anion exchange resin regeneration tower Is provided. (5) The desalination tower shall consist of condensate desalination equipment installed in a boiling water nuclear power plant.

[0034]

EFFECTS OF THE INVENTION According to the present invention, TOC elution from the ion-exchange resin due to rapid TOC elution immediately after temperature rise and contact with highly dissolved oxygen water to cause oxidative deterioration can be suppressed, and therefore water quality is maintained. Can be secured.

[Brief description of drawings]

FIG. 1 is a system diagram for explaining an example of a method of regenerating an ion exchange resin for a desalting apparatus and an example of the regenerating apparatus according to the present invention.

FIG. 2 is a diagram showing TOC elution behavior by the regeneration method in FIG.

FIG. 3 is a system diagram showing a primary system of a nuclear reactor plant for explaining a conventional example.

FIG. 4 is a system diagram showing a conventional ion exchange resin regenerating apparatus for a desalting apparatus.

5 is a diagram showing the TOC elution behavior with respect to the temperature change of the ion exchange resin in the apparatus of FIG.

FIG. 6 is a diagram showing the characteristics of TOC elution behavior (effect of dissolved oxygen) from the ion exchange resin depending on the dissolved oxygen concentration.

[Explanation of symbols]

20 ... Desalination tower, 21 ... Ion exchange resin, 22 ... Cation exchange resin regeneration tower, 23 ... Anion exchange resin regeneration tower, 24 ... Sulfuric acid diluting device, 25 ... Sulfuric acid supply device, 26 ... Caustic soda diluting device, 27
... hot water supply device, 28 ... caustic soda supply device, 29 ... condensate inlet pipe, 30 ... condensate outlet pipe, 31 ... hot water inlet pipe, 32 ... hot water inlet pipe, 33 ... hot water inlet pipe, 34 ... condensate thermometer, 35 ... Waste liquid outlet pipe, 36 ... Nitrogen supply device.

Claims (4)

[Claims] 1. An ion exchange resin in a desalting tower having an inlet pipe and an outlet pipe of treated water to be purified is transferred to a cation exchange resin regeneration tower and an anion exchange resin regeneration tower for regeneration or backwashing and regeneration thereof. Alternatively, the backwashed ion exchange resin is returned to the desalting tower, and deionized water having a temperature equal to the temperature of the water to be purified is supplied to the desalting tower to remove the regenerated or backwashed ion exchange resin. A method for regenerating an ion-exchange resin in a desalination apparatus, which comprises washing with water at room temperature. 2. The method for regenerating an ion exchange resin in a desalination apparatus according to claim 1, wherein the de-ambient temperature water comprises de-air temperature water for cleaning deaerated with nitrogen gas. 3. A desalination tower having an inlet pipe for water to be purified filled with an ion exchange resin, a cation exchange resin regeneration tower connected to this desalination tower, and an anion connected to this cation exchange resin regeneration tower. An ion exchange resin regeneration tower, a hot water inlet pipe connected to each of the desalting tower, the cation exchange resin regeneration tower and the anion exchange resin regeneration tower, a hot water supply device connected to the hot water inlet pipe, and the cation exchange An ion exchange resin regeneration device in a desalination apparatus, comprising: a resin regeneration tower and a degassing gas supply device connected to the anion exchange resin regeneration tower. 4. The regenerator for ion exchange resin in a desalination apparatus according to claim 3, wherein a condensate thermometer is provided on the treated water inlet pipe to be purified.