JPH10192718A - Resin regenerator for condensate desalter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quality of treated water and to reduce the amt. of a waste liq. to be generated in a separation stage by improving the separation of an ion-exchange resin and preventing its reverse degeneration. SOLUTION: This regenerator is provided with an anionic resin regeneration tower 3 to be supplied with a cation-exchange resin and an anion-exchange resin from a condensate desalting tower 1 through a resin outlet pipeline 10 and a cationic resin regeneration tower 4 for storing the cation-exchange resin. A cationic resin outlet pipeline 20 is connected to the lower part of the anionic resin regeneration tower 3 and used also as a whole ion-exchange resin outlet pipe to return the whole resin to the condensate desalting tower 1. An internally held water return pipeline 13, a developing water injection pipeline 17, a sodium hydroxide feed pipe 18, an agitating water injection pipeline 11, a waste liq. transfer pipe 22 and a cationic resin return pipeline 12 are connected to the anionic resin regeneration tower 3. A cation-exchange resin inlet pipeline 21, a sulfuric acid feed pipe 19, a drain pipeline 23 and a cationic resin return pipeline 12 are connected to the cationic resin regeneration tower 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin regeneration device for a condensate desalination unit of a power plant for regenerating an ion exchange resin in a condensate desalination tower.

[0002]

2. Description of the Related Art Generally, in a conventional nuclear power plant, condensing and purifying water are performed in order to operate a nuclear reactor with high reliability and maintain the integrity of a primary coolant.
FIG. 6 illustrates a general system of a conventional nuclear power plant.

In FIG. 6, reference numeral 24 denotes a boiling water reactor. The high-temperature, high-pressure steam generated in the reactor 1 is sent to a turbine 25, and the turbine 25 is rotated to drive a generator 26.
The steam that has performed the work in the turbine 25 flows into the main condenser 27 and is condensed by cooling seawater.The air is extracted by the low-pressure condensate pump 28 connected in parallel with three units, the air extractor 29 and the ground steam condenser
After passing through 30, it is sent to the condensate desalination device 31.

[0004] Granular positive and negative ion exchange resins (0.4 mm in diameter) loaded inside the condensate desalination unit 31 are used.
The condensate water by 1.2 mm) soluble metal ion insoluble impurities (cladding), when seawater leakage, C1 ^- impurities such is purified. Thereafter, the water is sent to the low-pressure feed water heater 33 by the three high-pressure condensate pumps 32 connected in parallel, and further pressurized and heated through the feed water pump 34 and the high-pressure feed water heater 35, and is returned to the reactor 31 as feed water.

[0005] The structure of the condensate desalination apparatus 31 will be described with reference to FIG. As shown in FIG. 7, the condensate desalination apparatus 31 is roughly composed of a condensate desalination tower 36 and a regeneration system 42. In this condensate desalination tower 36, a granular ion exchange resin 37 is laminated.
Condensate is supplied into the condensate desalination tower 36 from the top of the condensate desalination tower 36 through the condensate inlet pipe 38, and clad and ionic impurities contained in the condensate are captured by the ion exchange resin 37. The condensate purified by the condensate desalination tower 36 flows from the condensate outlet pipe 39 through the resin strainer 40 and is sent to the next device (not shown).

Here, the ion exchange resin in the condensate demineralization tower 36
37 removes the clad attached to the ion-exchange resin 37 in order to increase the pressure differential pressure at the inlet and outlet and increase the amount of leak of the clad to the tower outlet by capturing the clad,
Further, backwashing with water and air is performed to discharge the water outside the system. In addition, when the ion exchange capacity is consumed by capturing the ionic impurities, chemical regeneration is performed to restore the ion exchange capacity by using a chemical.

[0007] The ion exchange resin 37 is sent from the condensate desalination tower 36 to the cation exchange resin regeneration tower 43 via the pipe 41 and backwashed, and then the cation exchange is performed by utilizing the difference in specific gravity of each. The anion exchange resin separated into a resin layer and an anion exchange resin layer and laminated on the upper side is sent to an anion exchange resin regeneration tower 44.

After each of the resins divided into the cation exchange resin regeneration tower 43 and the anion exchange resin regeneration tower 44 is backwashed again, sulfuric acid is transferred to the anion exchange resin regeneration tower 44 and the caustic soda cation exchange resin Chemical regeneration is performed by passing the medicine through the regeneration tower 43, and then the anion exchange resin is sent to the cation resin regeneration tower 43. Then, after mixing and washing, the mixture is returned to the condensate desalination tower 36 through the resin return pipe 45, and the condensate purification is performed again.

The waste liquid from the cation exchange resin regeneration tower 43 and the anion exchange resin regeneration tower 44 is drained by a drain strainer.
It is sent to a waste treatment facility 47 through 46, and is subjected to filtration and desalination or concentration treatment. The cation exchange resin regeneration tower 43, the anion exchange resin regeneration tower 44, and the drain strainer 46 constitute a regeneration system 42 of the condensate desalination unit 31.

FIG. 8 shows a conventional cation exchange resin regeneration tower.
The structure of 43 will be described. In the cation exchange resin regeneration tower 43,
Resin inlet pipe for supplying resin transferred from condensate desalination tower 36
41, water injection pipe 5 for introducing water for spreading and separating resin
0, an anion exchange resin outlet pipe 51 for extracting the upper layer anion exchange resin after separation, a sulfuric acid inlet pipe 49 for introducing sulfuric acid as a regenerating chemical of the cation exchange resin, and a condensate desalination tower 36 for the mixed ion exchange resin. A resin outlet pipe 52 for feeding the water to the container is connected.

The resin transported to the cation exchange resin regeneration tower 43 is developed by the rising water flow injected from the resin stirring water injection pipe 48. The water injection from the resin stirring water injection pipe 48 is stopped, the resin is allowed to settle naturally, and the two resins are separated by utilizing the specific gravity difference between the positive and anion exchange resins.

FIG. 9 is a schematic sectional view showing the separation surface of the ion exchange resin layer in the cation exchange resin regeneration tower 43. An anion exchange resin layer A is formed in an upper part of the cation exchange resin regeneration tower 43, and a cation exchange resin layer B is formed in a lower part of the resin layer A. The mixed resin layer C in which the ion exchange resin and the anion exchange resin are mixed with each other is formed.

[0013]

As described above, the mixed resin layer C of the cation exchange resin and the anion exchange resin is formed in the cation exchange resin regeneration tower 43. This is inevitable due to the specific gravity particle size distribution characteristics of both resins. For this reason, a certain amount of the cation exchange resin is mixed into the anion exchange resin regeneration tower 44, and a certain amount of the anion exchange resin remains in the cation exchange resin regeneration tower 43. The mixed or remaining resin comes into contact with caustic soda and sulfuric acid chemicals and is regenerated in the following form.

Cation exchange resin (R _C ): R _C —Na ⁺ anion exchange resin (R _A ): R _A = SO ₄ ²⁻ , R _A —H
SO ₄ ^- When the reverse-regenerated resins are returned to the condensate and desalination tower 36 and the condensate is treated, the next reaction proceeds by hydrolysis.

[0015]

Embedded image Or

Embedded image In other words, there is a problem that Na ⁻ and SO ₄ ⁻ ions leak into the treated water and cause a risk of water quality.

The present invention has been made to solve the above-mentioned problems, and can improve resin separation, prevent reverse regeneration, improve the quality of treated water, and reduce the amount of waste liquid generated in the separation step. An object of the present invention is to provide a resin regeneration device for a condensate desalination device.

[0017]

According to a first aspect of the present invention, an anion exchange resin layer is formed on an upper portion and a cation exchange resin is formed on a lower portion by a cation exchange resin and an anion exchange resin supplied from a condensate desalination tower. An exchange resin layer, an anion resin regeneration tower in which a mixed resin layer of an anion exchange resin and a cation exchange resin is formed in the middle, and a cation resin regeneration tower that stores the cation exchange resin A cation exchange resin outlet pipe is provided at a lower portion of the anion resin regeneration tower, and the cation exchange resin outlet pipe also serves as an outlet pipe for all ion exchange resins to be returned to the condensate desalination tower. A water injection pipe for stirring the cation exchange resin is provided in the anion resin regeneration tower below the cation exchange resin layer, and an injection pipe for developing the mixed resin layer and the anion exchange resin layer is provided below the mixed resin layer. The water pipe is connected,
A water return pipe for development is connected to the upper part of the anionic resin regeneration tower, an alkaline chemical injection pipe is connected to the anionic resin regeneration tower, and an acidic chemical injection pipe is connected to the cation resin regeneration tower. It is characterized by.

According to the first aspect, after the cation exchange resin and the anion exchange resin supplied in a mixed state from the condensate demineralization tower are transferred to the anion resin regeneration tower, the resin is subjected to cation and anion exchange. In a resin regenerating unit for a condensate desalination unit that separates into an ion-exchange resin layer, water is injected from the stirring water injection pipe below the anion regeneration tower in the order of an anion exchange resin layer, a mixed resin layer, and a cation exchange resin layer from the top. Once separated, water is injected from the injection pipe of the anion regeneration tower, and the anion exchange resin layer and the mixed resin layer are extended to the upper part of the anion resin regeneration tower. And the flow rate at which only the cation exchange resin sediments.

As a result, an anion exchange resin layer is formed above the developing water injection pipe of the anion resin regeneration tower, and a cation exchange resin layer is formed below. In this state, the cation exchange resin is transferred to the cation resin regeneration tower from the cation exchange resin outlet pipe while water is injected from the stirring injection pipe below the anion resin regeneration tower. Therefore, the mixed resin layer can be easily separated into the cation exchange resin and the anion exchange resin, and the separation of the resin can be reliably performed.

According to a second aspect of the present invention, in the anion resin regeneration tower, the water for developing the anion exchange resin layer and the mixed resin layer comprises water retained in the anion resin regeneration tower.

Thus, the amount of waste liquid at the time of resin separation can be reduced. That is, when replenishing water or the like is used as the developing water for the anion exchange resin layer and the mixed resin layer, all the developing water is transferred to the waste liquid treatment system as a waste liquid. From this, the present invention can improve the resin separability without increasing the amount of waste liquid.

The invention according to claim 3 is characterized in that an injection pump for supplying water for developing the anion exchange resin layer and the mixed resin layer and a flow control valve on the pump outlet side are provided. Thereby, the water inside the anion resin regeneration tower can be circulated.

According to a fourth aspect of the present invention, there is provided a control system for controlling a developing water flow rate of the anion exchange resin layer and the mixed resin layer to a predetermined amount. When the development of the anion exchange resin layer and the mixed resin layer starts, the developing water can be controlled by giving a control signal of a flow controller to a flow control valve provided on an outlet side of a water injection pump for supplying the developing water. .

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a condensate desalination apparatus according to the present invention will be described with reference to FIGS. FIG.
Is a system diagram of a regeneration system, and FIGS. 2 to 5 are partial system diagrams showing the configuration inside the anion resin regeneration tower and the vicinity of the cation resin regeneration tower.

In FIG. 1, reference numeral 1 denotes a condensate demineralization tower, in which an anion resin regeneration tower 3 to which an ion exchange resin 2 is supplied, a cation resin regeneration tower 4 for storing a cation exchange resin, Further, a waste treatment facility 6 for treating the drain of the anion resin regeneration tower 3 and the cation resin regeneration tower 4 is provided.

In the anion resin regenerating tower 3, when the ion exchange resin 2 supplied from the condensate desalination tower 1 is settled, as shown in FIG. Layer A has a cation exchange resin layer B below.
However, a mixed resin layer C of both resins is formed in an intermediate portion which is a boundary between the two.

A condensate supply pipe 7 is connected to the upper part of the condensate desalination tower 1, and a condensate outlet pipe 9 provided with a strainer 8 is connected to a lower part thereof. The lower part of the condensate desalination tower 1 and the upper part of the anionic resin regeneration tower 3 are connected by a resin supply pipe 10.

A lower part of the anion resin regeneration tower 3 is connected to a stirring water supply pipe 11 for introducing water for developing and separating the entire ion exchange resin 2, and an upper part thereof is provided inside the anion resin regeneration tower. A water return pipe 13 is connected. This return pipe 13
Is connected to one end of a water injection pipe 17 for development via an injection pump 14 for circulating the retained water, a control valve 15 for adjusting the amount of water injected, and a flow rate controller 16, and the other end of the water injection pipe 17 for development is connected to an anion. It is connected to the resin regeneration tower 3. The water injected from the water injection pipe 17 is water for developing the anion exchange resin and the mixed resin layer.

A caustic soda supply pipe 18 is connected to the anionic resin regeneration tower 3, and a sulfuric acid supply pipe 19 is connected to the cation resin regeneration tower 4. A cation exchange resin outlet pipe 20 is connected to a lower portion of the anion resin regeneration tower 3, and the cation resin is transferred to the cation resin regeneration tower 4 via a cation resin inlet pipe 21.

The cation exchange resin chemically regenerated with sulfuric acid is returned to the anion resin regeneration tower 3 via the cation resin return pipe 12. On the other hand, the anion exchange resin chemically regenerated with caustic soda and the cation exchange resin returned from the cation resin regeneration tower 4 are mixed and washed in the anion resin regeneration tower 3 and then pass through the cation exchange resin outlet pipe 20. Condensate desalination tower 1
Transferred to

The waste liquid transfer pipe 22 connected to the lower part of the anion resin regenerator 3 and the drain pipe 23 connected to the lower part of the cation resin regenerator 4 join together and are connected to the drain strainer 5. Are connected to a waste treatment facility 6.

Next, the operation of the present embodiment according to the above configuration will be described. Ion exchange resin 2 in condensate desalination tower 1
Is transferred to the anionic resin regeneration tower 3 via the resin supply pipe 10. Next, water is injected from the stirring water injection pipe 11 into the anionic resin regeneration tower 3, and the ion exchange resin in a mixed state spontaneously settles in the injected water due to the upward flow.

At this time, as shown in FIG. 2, the cation exchange resin and the anion exchange resin have an anion exchange resin layer A on the upper side, a cation exchange resin layer B on the lower side, and
A mixed resin layer C in which both resins are mixed is formed near the boundary between the two.

Next, the injection pump 14 is started, and the internal water of the anion regeneration tower 3 is used as a developing water injection pipe adjusted to a predetermined flow rate by the flow control valve 15 based on a control signal of the flow controller 16, and is used as a developing irrigation pipe. Water was injected from 17 and the anion exchange resin layer A and the mixed resin layer C were spread to the upper part of the anion resin regeneration tower 3 as shown in FIG. The flow rate is such that only the resin settles.

As a result, as shown in FIG. 4, an anion exchange resin layer A is formed on the upper part of the developing water injection pipe 17 of the anion resin regeneration tower 3, and a cation exchange resin layer B is formed on the lower part.
In this state, a stirring injection pipe at the lower part of the anion resin regeneration tower 3
The cation exchange resin is transferred to the cation resin regeneration tower 4 from the cation exchange resin outlet pipe 20 through the cation exchange resin inlet pipe 21 while water is injected from 11.

Then, after the resin is separated as shown in FIG. 5, the injection of the developing water in the anionic resin regenerating tower 3 is stopped, and the anionic resin layer A is spontaneously settled.

Next, caustic soda is injected into the anionic resin regeneration tower 3 from the caustic soda supply pipe 18, and sulfuric acid is injected into the cation resin regeneration tower 4 from the sulfuric acid supply pipe 19. As the caustic soda passes through the anion exchange resin layer A and the sulfuric acid passes through the cation exchange resin layer B, the anion exchange resin and the cation exchange resin are chemically regenerated.

The sulfuric acid and caustic soda chemically regenerated in the anion resin regeneration tower 3 and the cation resin regeneration tower 4 are discharged from the waste liquid transfer pipe 22 and the drain pipe 23 and passed through the drain strainer 5 to a waste treatment facility. 6 is processed.

The cation exchange resin having undergone the chemical regeneration is returned to the anion resin regeneration tower 3 via the cation resin return pipe 12. The cation and anion exchange resins are finally washed and mixed in the anion resin regeneration tower 3, transferred from the cation exchange resin outlet pipe 20 to the condensate demineralization tower 1, and condensed again.

As described above, according to the present embodiment, the water injection pipe 17, the water injection pump 14, the flow control valve 15, and the flow control controller 16 are provided, so that the cation exchange resin And the anion exchange resin can be reliably separated. Furthermore, since the water retained inside the anionic resin regeneration tower 3 is used as the developing water, the amount of drain water generated here can be reduced.
The processing load on the waste treatment equipment 6 can be reduced.

[0041]

According to the present invention, the separation of resin is improved,
Reverse regeneration can be prevented, the quality of treated water can be improved, and the amount of waste liquid generated in the separation step can be reduced. In addition, since the treated water quality can be maintained well without bringing the reverse-regenerated ion exchange resin into the condensate demineralization tower, corrosive products of plant components are reduced, and the radioactivity level of the plant is reduced.
Radiation exposure can be reduced.

Further, since the amount of water necessary for separating the ion exchange resin can be reduced, the amount of waste liquid can be reduced. Therefore, the processing amount of the waste treatment equipment can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a resin regeneration apparatus for a condensate desalination apparatus according to the present invention.

FIG. 2 is a system diagram for explaining a regeneration operation of the ion exchange resin in FIG.

FIG. 3 is a system diagram for explaining the next step from the state of FIG. 2;

FIG. 4 is a system diagram for explaining the next step from the state of FIG. 3;

FIG. 5 is a system diagram for explaining the next step from the state of FIG. 4;

FIG. 6 is a general system diagram of a conventional nuclear power plant.

FIG. 7 is a system diagram of a regeneration system of the condensate desalination apparatus in FIG.

8 is a longitudinal sectional view of a cation exchange resin anion resin regeneration tower of the condensate desalination apparatus in FIG. 7;

9 is a schematic sectional view schematically showing a separation surface of an ion exchange resin layer in the cation resin regeneration tower in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Condensate desalination tower, 2 ... Ion exchange resin, 3 ... Anion resin regeneration tower, 4 ... Cation resin regeneration tower, 5 ... Drain strainer, 6 ... Waste treatment equipment, 7 ... Condensate inlet piping, 8 … Strainer, 9… Condenser outlet pipe, 10… Resin supply pipe, 11…
Water injection pipe for agitation, 12 ... Cation resin return pipe, 13 ... Anion resin regeneration tower internal water return pipe, 14 ... Injection pump,
15 ... Flow control valve, 16 ... Flow controller, 17 ... Irrigation pipe for deployment, 18 ... Caustic soda supply pipe, 19 ... Sulfuric acid supply pipe, 20 ...
Cation resin outlet pipe, 21 ... Cation exchange resin inlet pipe, 22 ... Waste liquid transfer pipe, 23 ... Drain pipe.

Claims (4)

[Claims] 1. An anion exchange resin layer at the upper part, a cation exchange resin layer at the lower part, and an anion at the middle part by the cation exchange resin and the anion exchange resin supplied from the condensate desalination tower. An anion resin regeneration tower in which a mixed resin layer of an exchange resin and a cation exchange resin is formed, and a cation resin regeneration tower for storing the cation exchange resin, a lower portion of the anion resin regeneration tower Is provided with a cation exchange resin outlet pipe, and this cation exchange resin outlet pipe also serves as an outlet pipe for all the ion exchange resin returned to the condensate demineralization tower, and the anion resin below the cation exchange resin layer. A water injection pipe for stirring the cation exchange resin is provided in the regeneration tower, and a water injection pipe for developing the mixed resin layer and the anion exchange resin layer is connected to a lower portion of the mixed resin layer, and a water injection pipe for the anion resin regeneration tower is provided. The deployment water return pipe is connected to the upper part An alkaline chemical injection pipe is connected to the anionic resin regeneration tower, and an acidic chemical injection pipe is connected to the cation resin regeneration tower. 2. The resin regenerating apparatus according to claim 1, wherein the water for developing the mixed resin layer and the anion exchange resin layer comprises water inside the anionic resin regenerating tower. 3. The resin regenerating apparatus according to claim 1, further comprising a water injection pump and a flow control valve for developing the mixed resin layer and the anion exchange resin layer. 4. The resin regeneration for a condensate desalination apparatus according to claim 1, further comprising a control system for controlling the flow rate of the developing water of the mixed resin layer and the anion exchange resin layer to a predetermined amount. apparatus.