JP2001079552A - Electric deionizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric deionizing device efficiently performing a desalt treatment for water to be treated being rich in a cation component and being mostly suited to a secondary system of water treatment in especially a pressurized water type atomic power plant. SOLUTION: In the electric deionizing device 1 having plural desalt rooms 5 charging ion exchange bodies 4 in the inside partitioned with a cation exchange membrane 2 and an anion exchange membrane 3 and plural concentration rooms 6 for receiving ions moving from the desalt rooms 5, between an anode 9 and a cathode 8, a volume proportional ratio (a cation exchange body/an anion exchange body) of the ion exchange bodies 4 charged into the device 1 is made to >=2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric deionization suitable for use in desalination of condensate in a secondary system of a pressurized water nuclear power plant and desalination of water to be treated which is rich in other cation components. Related to the device.

[0002]

2. Description of the Related Art Conventionally, in a pressurized water nuclear power plant, as secondary water treatment measures, pH adjustment by addition of ammonia, deoxygenation by addition of hydrazine, and desalination treatment by a condensate desalination apparatus have been performed. I have. The condensate desalination unit is installed downstream of the condenser, and the condensate from the condenser is desalted by the condensate desalination unit. Through to the steam generator.

In the steam generator, since impurities and corrosion products introduced into the system are concentrated, the water in the secondary system of the steam generator is partially drained, that is, blow-down.

Most of the scale adhering to the heat transfer tube of the steam generator is a corrosion product generated from the inner surface of the secondary system equipment and pipes, that is, iron oxide. In addition, the reduction of iron oxides brought into the steam generator, or the suppression of the generation of corrosion products from the secondary system equipment and piping are being attempted.

At present, the pH is adjusted to about 9.2 by AVT treatment, that is, by ammonia, and dehydration / reduction atmosphere is controlled by hydrazine to suppress the generation of corrosion products. It is a gas-liquid two-phase flow area, and the liquid phase on the surface of equipment and piping has a small effect of reducing ammonia and decreasing the pH because the gas-liquid distribution ratio of ammonia is 1 or more. Has been pointed out. For this reason, the ammonia concentration is increased,
It is planned to adopt a high pH treatment that suppresses iron elution by setting the pH to 9.2 or more, for example, about 9.8, and preventing the liquid-side pH from decreasing in the gas-liquid two-phase flow region.

However, in the AVT treatment, the pH is adjusted to 9.
When the concentration increases from 2 to 9.8, the concentration of ammonia becomes about 10 times, and the condensate desalination unit is operated by the H-OH type.
A plurality of desalination towers for regenerating the ion exchanger currently packed in 10 to 15 days per one desalination tower are installed, and regeneration is performed about once every two days for any of the desalination towers. However, it is necessary to carry out the reproduction in one to two days with respect to the current frequency. For this reason, there is a possibility that the time to regenerate multiple desalination towers may overlap, but it is not possible to regenerate several towers a day, and it is also possible to fill the resin amount of the desalination tower more than the current situation. Since it is not possible, H-OH type operation becomes practically impossible in the current condensate desalination tower with high pH operation. Therefore, in a plant operating at a high pH, the condensate treatment by the condensate desalination unit is not performed on the entire condensate, but is partially condensed or bypassed during normal operation without treating the entire condensate. A scheme to make this happen is planned.

Therefore, while providing the above-mentioned condensate bypass path, the blowdown water of the steam generator is desalinated using an electrodeionization apparatus that does not require regeneration with chemicals, and the desalination treatment is performed. A technique has been proposed in which blowdown water that has been returned is returned to a condensate system to perform secondary water treatment (JP-A-11-47560).

That is, in the high-pH operation, if an attempt is made to remove impurities in the condensate in the desalination tower of the condensate desalination apparatus, the ammonia load is large because the ammonia concentration is high.
The total amount of the resin in the desalination tower cannot be treated, and the condensate desalination unit is forced to perform a condensate partial treatment operation or a bypass operation. Therefore, even when the condensate desalination unit is bypassed, the steam generator blowdown water is continuously desalted and the desalinated water is returned, so that impurities in the secondary system are removed and the steam generator is damaged by corrosion. Can be prevented. As the steam generator blowdown water treatment device, an electrodeionization device that does not require regeneration with a chemical and can be operated continuously is optimal. The electrodeionization apparatus has one or more anodes and one or more cathodes, is separated by an anion exchange membrane and a cation exchange membrane, and moves through one or more deionization chambers filled with an ion exchanger and the ion exchange membrane. The system is composed of one or more concentration chambers for concentrating incoming ions, and is operated while being continuously regenerated by electric current.

[0009]

However, the conventional electrodeionization apparatus has been manufactured so that the ratio of the cation exchanger / anion exchanger of the ion exchanger charged in the desalting chamber is less than 2. For water to be treated rich in a cation component, for example, water to be treated containing a relatively high concentration of a cation component such as ammonia and / or hydrazine as described above, it is suitable for removing such a cation component. It was not something. In particular, as described above, sufficient performance could not be exhibited in the treatment of cation component-rich water such as steam generator blowdown water.

[0010] An object of the present invention is to efficiently desalinate water to be treated rich in cation components, and particularly to an electric power suitable for use in secondary water treatment when operating at high pH in a pressurized water nuclear power plant. A deionization device is provided.

[0011]

In order to solve the above-mentioned problems, an electrodeionization apparatus of the present invention is provided between an anode and a cathode.
An electrodeionization apparatus having a plurality of deionization chambers separated by a cation exchange membrane and an anion exchange membrane and filled with an ion exchanger therein, and a concentration chamber for receiving ions moving from the desalination chamber. Volume fraction of ion exchanger filled in the vessel (cation exchanger / anion exchanger)
Is set to 2 or more.

In this electrodeionization apparatus, in order to save power, a desalting chamber is divided into two small compartments divided by a cation exchange membrane on one side, an anion exchange membrane on the other side, and a middle ion exchange membrane in the center. A desalination chamber is filled with an ion exchanger, and the enrichment chambers are provided on both sides of the desalination chamber via the cation exchange membrane and the anion exchange membrane. It is preferable to adopt a structure that is arranged in a space. In particular, a desalination chamber is formed by stacking a cation exchange membrane, one frame with an inside hollowed out, an intermediate ion exchange membrane, another frame with an inside hollowed out, and an anion exchange membrane in this order. It preferably comprises an ion module. As an intermediate ion exchange membrane, for example,
It can be composed of a cation exchange membrane or a double membrane in which an anion exchange membrane is arranged at the front stage in the flow direction of the water to be treated and a cation exchange membrane is arranged at the rear stage.

[0013] The layer formation form of the ion exchanger packed in the desalting chamber is such that the volume fraction (cation exchanger / anion exchanger) of the ion exchanger packed in the entire electrodeionization apparatus is 2 or more. Although there is no particular limitation, it is preferable that the ion exchanger through which the water to be treated is finally passed in the desalting chamber is packed in a mixed bed form of an anion exchanger and a cation exchanger.

[0014] Such an electrodeionization apparatus according to the present invention is suitably used particularly for condensate desalination treatment in a pressurized water nuclear power plant, and more specifically, blowdown of a steam generator in a pressurized water nuclear power plant. The blowdown water that has been used for water desalination and that has been desalinated is returned to the condensate system.

In the electrodeionization apparatus according to the present invention thus constituted, the desalting efficiency for the cation component is reduced by setting the volume ratio of the cation exchanger / anion exchanger to 2 or more. The ratio can be drastically increased as compared with those having a volume ratio of less than 2, especially those having a volume fraction of about 1 which has been conventionally used conventionally. For example, when high pH operation is performed in the secondary system of a pressurized water nuclear power plant as described above, a large amount of a cation component (both about 0.5 ppm for both ammonia and hydrazine) is usually contained in the steam generator blowdown water. ing. Therefore, the desalting efficiency for the cation component can be drastically increased by setting the ion exchanger volume fraction filled in the electrodeionization apparatus to be cation exchanger / anion exchanger = 2 or more.

In configuring such an electrodeionization apparatus, by forming the desalination chamber from two small desalination chambers partitioned by an intermediate ion exchange membrane, the following operation and effect can be obtained. Will be added.

That is, conventionally, various attempts have been made to reduce the electric resistance of the electrodeionization apparatus in order to remove the impurity ions in the water to be treated with power saving by using the electrodeionization apparatus. In this case, in the desalting chamber, the filling method and the filling amount of the ion exchanger used in the desalting chamber,
Since it is determined by the required quality of the treated water, there is a limit in reducing the electric resistance of the desalination chamber. Therefore, measures are often taken to reduce the electrical resistance of the concentrating chamber. For example, Japanese Patent Application Laid-Open No. 9-24374 discloses a method in which an electrolyte is added and supplied to a concentration chamber to reduce the electric resistance of the concentrate. In addition, many methods have been reported for promoting the increase in conductivity by circulating concentrated water and reducing the electric resistance of the concentrating chamber.

However, in the method of reducing the electric resistance of the concentrating chamber by adding and supplying the electrolyte to the concentrating chamber, a pump, a chemical storage tank and a supply pipe for supplying the electrolyte to the concentrating chamber must be installed. This increases the installation area and the installation cost. In addition, there is a problem in that replenishment and management of medicines must be performed periodically, and labor is required despite the fact that the apparatus is a continuous regeneration type. In addition, the method of promoting the increase in the electrical conductivity by circulating the concentrated water and reducing the electric resistance of the concentrated chamber increases the hardness components such as calcium and magnesium contained in the concentrated water, thereby promoting the generation of scale. As a result, there is a problem that the electrical resistance increases as a result.

Therefore, by adopting a configuration in which the intermediate ion exchange membrane is used to partition the chamber into two small desalination chambers, the number of concentrating chambers per one desalination chamber filled with the ion exchanger is reduced to about half that of the conventional one. And the electrical resistance of the electrodeionization device can be significantly reduced. In addition, since the number of the concentrating chambers is relatively small as compared with the conventional apparatus, the ion concentration of the concentrated water flowing through the concentrating chamber can be increased, the conductivity is improved, and the electric resistance is further reduced. In addition, the flow rate of the concentrated water flowing in the concentration chamber can be increased, and scale in the concentration chamber is less likely to occur. Further, by dividing into two small desalination chambers, the ion exchanger filled in each small desalination chamber can be converted into a single ion exchanger or an anion exchanger and a cation exchanger depending on the purpose of the treatment. It can be a single type of mixed ion exchanger, and the thickness of each small desalination chamber filled with the ion exchanger should be set to the optimum thickness to reduce electric resistance and obtain high current efficiency Becomes possible. In other words, if a single deionization chamber is filled with a plurality of types of ion exchangers, the optimal thickness for reducing the electric resistance and increasing the current efficiency differs depending on the type of each ion exchanger. It is difficult to set the thickness to the optimum thickness, but when filling each small desalination chamber with only a single type of ion exchanger, it is necessary to set the thickness to achieve both low electrical resistance and high current efficiency. It becomes possible.

Further, the transport number (that is, the transmittance of the ions to be removed) of the ion exchange membrane constituting the desalting chamber is not substantially 1, and even the ion exchange membrane which is said to have high performance is 0. If the ion-exchange layer through which the water to be treated is finally passed is a single bed layer of a cation exchanger or a single bed layer of an anion exchanger, the water is concentrated from the desalting chamber. The anion component or cation component that has moved to the chamber may move further to the next desalination chamber by the transport number of 0.02 or less (that is, the ion exchange membrane of the next desalination chamber may invade this amount). May not be prevented), and may flow out to the treated water side to lower the water quality.
Therefore, by using a mixed bed of a cation exchanger and an anion exchanger as the last ion-exchanger to pass water, it is sufficient for either the anion component or the cation component to move again from the concentration chamber to the desalination chamber. Processing can be performed, and high-purity treated water can be obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an electrodeionization apparatus according to a first embodiment of the present invention, and FIG.
And FIG. 3 show an example of its use. 4 and 5 show an electrodeionization apparatus according to a second embodiment of the present invention, and FIG. 6 shows an example of its use. FIG.
1 shows an example of a system in which an electrodeionization device according to the present invention is incorporated in a secondary system of a pressurized water nuclear power plant.

First, in the electrodeionization apparatus 1 according to the first embodiment shown in FIG. 1, the cation exchange membranes 2 and the anion exchange membranes 3 are arranged alternately and spaced apart from each other. The space formed by 3 is filled with every other ion exchanger 4 to form a desalination chamber 5. Portions of the anion exchange membrane 3 and the cation exchange membrane 2 which are located next to the desalting chamber 5 and are not filled with the ion exchanger are formed in a concentration chamber 6 for flowing concentrated water. The concentration chamber 6 receives ions moving from the desalting chamber 5 via each ion exchange membrane.

A plurality of desalting chambers 5 and concentrating chambers 6 as described above are arranged between the anode 7 and the cathode 8. The insides of the anode 7 and the cathode 8 are formed in an anode chamber 9 and a cathode chamber 10, respectively. The anode chamber 9 and the cathode chamber 10 may be
The outermost concentration chamber 6 is partitioned by a cation exchange membrane or an anion exchange membrane, or a simple membrane having no ion exchange property (shown in FIGS. 2 and 3).

A direct current is passed between the anode 7 and the cathode 8, and the water to be treated flows into each desalting chamber 5 from the water inflow line 11, and the concentrated water flows from the concentrated water inflow line 12 to each of the concentrating chambers 6. And the electrode water inflow lines 13, 1
Electrode water flows from 3 into the anode chamber 9 and the cathode chamber 10, respectively. The to-be-treated water flowing from the to-be-treated water inflow line 11 flows down the desalting chamber 5, and the ions to be removed are moved to the concentration chamber 6 via the ion exchange membranes on both sides. The concentrated water flowing from the concentrated water inflow line 12 rises in each of the concentration chambers 6, receives the impurity ions moving through the cation exchange membrane 2 and the anion exchange membrane 3, and concentrates as the concentrated water in which the impurity ions are concentrated. Electrode water flowing out of the water outflow line 14 and further flowing in from the electrode water inflow lines 13, 13 flows out of the electrode water outflow lines 15, 15. Then, the desalinated water treated in the desalination chamber 5 is obtained through the deionized water outflow line 16.

The ion exchanger 4 filled in the desalting chamber 5 is
The volume fraction, that is, the ratio of cation exchanger to anion exchanger (cation exchanger / anion exchanger) is
Two or more.

The form of filling the ion exchanger 4 into the desalting chamber 5 is not particularly limited as long as the volume fraction is 2 or more. For example, as shown in FIG. 2, each of the desalting chambers 5 may be filled in the form of a mixed bed M of a cation exchanger and an anion exchanger, and the volume fraction thereof may be 2 or more. Alternatively, as shown in FIG. 3, in the flow direction of the water to be treated, the front stage is filled in the form of a single bed K of a cation exchanger, and the rear stage is filled in the form of a mixed bed M of a cation exchanger and an anion exchanger. The volume fraction can be set to 2 or more. In any of the filling modes, it is preferable that the ion exchanger through which the water to be treated is finally passed in the desalting chamber 5 is a mixed bed M of a cation exchanger and an anion exchanger.

In the electrodeionization apparatus 1 according to this embodiment which is configured as shown in FIG. 1 and used in the form shown in FIGS. 2 and 3, the volume fraction of the cation exchanger / anion exchanger is used. Is set to 2 or more, the desalting efficiency with respect to the cation component can be drastically increased as compared with the conventional one where the volume fraction is about 1. Therefore, an optimal electrodeionization apparatus can be used for water to be treated rich in cation components. For example, in a secondary system of a pressurized water nuclear power plant to be described later, especially when high pH operation is performed, a large amount of cation components (both 0.5 ppm for both ammonia and hydrazine) are contained in the steam generator blowdown water.
The blowdown water is desalted by using an electrodeionization apparatus in which the ion exchanger volume fraction is 2 or more as the cation exchanger / anion exchanger as described above. In addition, the desalting efficiency for the cation component can be drastically increased.

The ion exchanger 4 finally passed through the desalting chamber 5 is formed as a mixed bed of a cation exchanger and an anion exchanger. Can be appropriately removed even if is re-migrated into the desalting chamber 5.

In the electrodeionization apparatus 21 according to the second embodiment shown in FIG. 4 and FIG.
2. The intermediate ion exchange membranes 24 and the anion exchange membranes 23 are alternately arranged at a distance, and the space formed by the cation exchange membranes 22 and the intermediate ion exchange membranes 24 is filled with the ion exchanger 25 to perform the first small removal. Salt rooms 26a, 26b, 26c, 26d
And the intermediate ion exchange membrane 24 and the anion exchange membrane 23
Is filled with the ion exchanger 25 in the space formed by
Small desalination chambers 27a, 27b, 27c, and 27d are formed, and the first small desalination chamber 26a and the second small desalination chamber 27a form a desalination chamber 28.
a, the first small desalination chamber 26b and the second small desalination chamber 27b, the desalination chamber 28b, the first small desalination chamber 26c and the second small desalination chamber 27c, the desalination chamber 28c, the first small desalination chamber 26d and 2nd small desalination room 27d
Form a desalination chamber 28d. On both sides of each desalination room,
A concentration chamber 29 not filled with the ion exchanger 25 is formed, and the concentration chamber 29 receives ions moving from each small desalination chamber via each ion exchange membrane.

A plurality of desalting chambers 28a to 28d and a concentration chamber 29 as described above are arranged between the anode 30 and the cathode 31. The insides of the anode 30 and the cathode 31 are formed in an anode chamber 32 and a cathode chamber 33, respectively. The anode chamber 32 and the cathode chamber 33 are provided, if necessary, with respect to the outermost concentration chamber 29.
It is separated by a cation exchange membrane, an anion exchange membrane, or a simple membrane having no ion exchange property (shown in FIG. 6).

The above-mentioned desalting chambers 28a to 28d each comprise a deionization module formed by two internally hollowed frames and three ion exchange membranes. That is, FIG.
As shown in FIG. 1, one deionization module 51
The cation exchange membrane 22 is sealed on one side of the frame 52, the hollow portion of the first frame 52 is filled with the ion exchanger 25, and then the other portion of the first frame 52 is subjected to intermediate ion exchange. The membrane 24 is sealed to form a first small desalination chamber. Next, the second frame 53 is sealed so as to sandwich the intermediate ion exchange membrane 24, and the ion-exchanger 2 is
5, and then the other portion of the second frame 53 is sealed with the anion exchange membrane 23 to form a second small desalting chamber. The ion exchange membranes 22, 23, and 24 are relatively soft. When the ion exchanger 25 is filled in the first frame 52 and the second frame 53 and both surfaces thereof are sealed with the ion exchange membrane. In order to prevent the ion exchange membrane from bending and the packed layer of the ion exchanger 25 from becoming uneven, the first frame 52 and the second
A plurality of ribs 54 are vertically provided in the space of the frame 53. Also,
Although not shown in the drawings, the inlet of the water to be treated or the outlet of the treated water is located above the first frame 52 and the second frame 53, and the outlet or the treated water is located below the frame. A water inlet is provided. FIG. 4 shows a state in which a plurality of such deionization modules 51 are arranged side by side with a spacer (not shown) interposed therebetween. A cathode 31 is provided.

By passing a direct current between the anode 30 and the cathode 31,
Each of the first desalination chambers 26a to 26
d, the concentrated water flows from the concentrated water inflow line 35 into each of the concentration chambers 29, and the electrode water flows from the electrode water inflow lines 36, 36 into the anode chamber 32 and the cathode chamber 33, respectively. Is flowed in. Treated water inflow line 34
Treated water flowing from the first small desalination chambers 26a to 26d
And the impurity ions are removed when passing through the packed bed of the ion exchanger 25. Furthermore, the first small desalination chamber 26a
The effluent that has passed through the treated water outflow line 37 through 26d flows down through the second small desalination chambers 27a through 27d through the treated water inflow line 38 of the second small desalination chambers 27a through 27d. When passing through the packed bed of the exchanger 25, impurity ions are removed, and deionized water is obtained from a deionized water outflow line 39. The concentrated water flowing from the concentrated water inflow line 35 rises in each of the concentration chambers 29, receives impurity ions moving through the cation exchange membrane 22 and the anion exchange membrane 23, and converts the concentrated ions into concentrated water. Electrode water flowing out of the concentrated water outflow line 40 and further flowing in through the electrode water inflow lines 36, 36 flows out of the electrode water outflow lines 41, 41. By the above operation, impurity ions in the water to be treated are electrically removed.

The intermediate ion exchange membrane 24 may be either a single cation exchange membrane or a double membrane in which an anion exchange membrane is arranged at the front and a cation exchange membrane is arranged at the rear in the flow direction of the water to be treated. Good. When a double membrane is used, the height (area) of each of the anion exchange membrane and the cation exchange membrane is appropriately determined according to the quality of the water to be treated or the purpose of the treatment.

The thickness of the first small desalination chamber or the second small desalination chamber is not particularly limited, and the type of ion exchanger to be filled in the first small desalination chamber or the second small desalination chamber and the filling method The optimum thickness may be determined according to the following.

The ion exchanger 25 filled in the desalting chambers 28a to 28d has a volume fraction, that is, a ratio of cation exchanger to anion exchanger (cation exchanger / anion exchanger) of 2 or more. I have.

The desalting chambers 28a to 28d of the ion exchanger 25
As long as the volume fraction is 2 or more,
There is no particular limitation. For example, as shown in FIG. 6, if each of the small desalting chambers 26a to 26d and 27a to 27d is packed in the form of a mixed bed M of a cation exchanger and an anion exchanger and the volume fraction thereof is 2 or more, Good. Alternatively, although not shown, the first small desalination chambers 26a to 26d are packed in the form of a single bed of a cation exchanger, and the second small desalination chambers 27a to 27d are filled.
7d may be filled in the form of a mixed bed M of a cation exchanger and an anion exchanger, and the volume fraction may be 2 or more as a whole. In any of the filling modes, the desalting chambers 28a to 28a
In 28d, the ion exchanger through which the water to be treated is finally passed is preferably a mixed bed M of a cation exchanger and an anion exchanger.

The structure shown in FIG.
In the electrodeionization apparatus 21 according to the present embodiment used in the form shown in FIG. 1, the volume ratio of the cation exchanger / anion exchanger to be filled is set to 2 or more, so that it is conventionally used normally. The desalting efficiency for the cation component can be drastically increased as compared with the case where the volume fraction is about 1. Therefore, an optimal electrodeionization apparatus can be used for water to be treated rich in cation components. For example, in a secondary system of a pressurized water nuclear power plant to be described later, especially when high pH operation is performed, a large amount of cation components (both about 0.5 ppm for both ammonia and hydrazine) are contained in the steam generator blowdown water. However, in the desalting treatment of the blowdown water, the desalting efficiency with respect to the cation component is increased by using an electrodeionization apparatus having the above ion exchanger volume fraction of 2 or more for the cation exchanger / anion exchanger. Can be dramatically increased.

The ion exchanger 25, which is finally passed through the desalting chambers 28a to 28d, is formed as a mixed bed of a cation exchanger and an anion exchanger. Even if any of them re-enters the desalting chambers 28a to 28d, the ions can be properly removed.

Further, since each of the desalting chambers 28a to 28d is divided into two small desalting chambers via the intermediate ion exchange membrane 24, the number of the concentrating chambers per one of the desalting chambers 28a to 28d is reduced. The electric resistance of the electrodeionization apparatus can be significantly reduced. In addition, since the number of concentrating chambers is relatively small as compared with the conventional apparatus, the ionic concentration of the concentrated water flowing through the concentrating chamber can be increased, the conductivity is improved, and the electric resistance is further reduced. In addition, the flow rate of the concentrated water flowing in the concentration chamber can be increased, and scale in the concentration chamber is less likely to occur.

Further, the ion exchanger 25 to be filled in each of the two divided small desalting chambers can be of a single type (mixed bed of cation exchanger and anion exchanger, or cation exchanger). (Exchanger single bed), and each small desalination chamber can be set to the optimum thickness to reduce the electric resistance and increase the current efficiency. This also reduces the electric resistance and further saves power. Can be planned.

The electrodeionization apparatus according to the first embodiment or the second embodiment as described above is suitable for use in secondary water treatment in a pressurized water nuclear power plant.

For example, as shown in FIG. 7 showing a secondary system line of a pressurized water nuclear power plant, the steam generator 61 has a steam pipe 6.
2, a turbine 63 is connected, and a condenser 64 is connected to the turbine 63. 65 is a generator.

In order to return the condensed water generated in the condenser 64, that is, the condensate, to the steam generator 61, the condenser 64 and the steam generator 61 are connected between the condenser 64 and the steam generator 61 as a condensing circuit. A condensing pipe 66 is provided. A condensing pump 67, a condensate desalination device 68, a deaerator 69, and a condensing pipe 66 are provided along the direction from the condenser 64 to the steam generator 61.
Each device of the feed water heater 70 is provided on the line of the condenser 66.

Condenser pipe 6 connected to condensate desalination device 68
6 is provided with a bypass pipe 71 as a bypass passage in parallel with the condensate desalination device 68 so that condensate is condensed by the condensate desalination device 6.
8. It is configured such that water can pass through any of the bypass pipes 71. Reference numeral 72 denotes a water flow switching valve.

The steam generator 61 is provided with a take-out pipe 73 for taking out blowdown water, and the other end of the take-out pipe 73 is connected to an electrodeionization device 74 via a cooler (not shown) in the middle thereof. Have been. Further, the electrodeionization device 7
A treated water pipe 75 is provided between the outlet of the desalting chamber 4 and the condenser 64 as a return passage connecting them, so that the treated water can be returned to the steam generator 61 via the condenser 64. It is configured. A concentrated water outflow pipe 76 is provided at the outlet of the concentration chamber of the electrodeionization device 74.
The concentrated water flowing out of the system 4 is discharged outside the system. The electrodeionization device according to the first embodiment or the second embodiment can be used as the electrodeionization device 74.

In the system configured as described above, by providing the bypass passage (bypass pipe 71),
The condensate desalination unit 68 can be partially condensed or partially bypassed, and can be operated without applying a high load to the condensate desalination unit 68 even in the case of high pH operation. It becomes possible. Then, by using the electrodeionization apparatus (74 in FIG. 7) according to the embodiment for the treatment of blowdown water of a cation component-rich steam generator containing 0.1 ppm or more of ammonia and 0.1 ppm or more of hydrazine, Even when high pH operation is employed, desalination of blowdown water becomes possible, and impurities in the secondary system can be removed by returning desalted blowdown water to the condensate reflux system. It is possible to take measures against corrosion of the steam generator and to prevent damage to the thin tube of the steam generator.

Incidentally, the electrodeionization apparatus according to the first embodiment or the second embodiment was applied to a system similar to that shown in FIG. 7 and tested under the following conditions. As a result, the results shown in Table 1 were obtained. . Desalination chamber flow rate: 0.12 m ³ / h Concentration chamber flow rate: 0.03 m ³ / h Raw water temperature: 45 ° C Current value: 2 A Resistivity is converted to 25 ° C

[0048]

[Table 1]

As can be seen from Table 1, Example 1 of the present invention
In Nos. 4 to 4, the concentration of ammonia and hydrazine can be significantly reduced by the desalination treatment of the steam generator blowdown water as compared with Comparative Example 1 (conventional electrodeionization apparatus), and the electric resistance (resistance) (Reciprocal of rate) was further reduced to save power.

[0050]

As described above, according to the electrodeionization apparatus of the present invention, the water to be treated rich in the cation component can be efficiently desalted, and the water used in the pressurized water nuclear power plant can be operated at a high pH. The most suitable electrodeionization apparatus can be provided for use in the desalination treatment of secondary system water, especially steam generator blowdown water.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrodeionization apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of use of the device of FIG.

FIG. 3 is a schematic view showing another example of use of the apparatus of FIG. 1;

FIG. 4 is a schematic configuration diagram of an electrodeionization device according to a second embodiment of the present invention.

FIG. 5 is an exploded perspective view of one deionization module of the apparatus of FIG. 2;

FIG. 6 is a schematic view showing an example of use of the device of FIG. 2;

FIG. 7 is an equipment system diagram of a secondary system line of the pressurized water nuclear power plant.

[Explanation of symbols]

 1,21,74 Electrodeionizer 2,22 Cation exchange membrane 3,23 Anion exchange membrane 4,25 Ion exchanger 5,28a, 28b, 28c, 28d Desalination room 6,29 Concentration room 7,30 Anode 8, 31 Cathode 9, 32 Anode compartment 10, 33 Cathode compartment 24 Intermediate ion exchange membrane 26a, 26b, 26c, 26d First small desalination chamber 27a, 27b, 27c, 27d Second small desalination chamber 51 Deionization module 52 First Frame 53 Second frame 54 Rib 61 Steam generator 63 Turbine 64 Condenser 65 Generator 68 Condensate desalination device 69 Deaerator 70 Feedwater heater 71 Bypass pipe (bypass path) 75 Treatment water pipe

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[Procedure amendment]

[Submission date] July 24, 2000 (2007.2
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

In this electrodeionization apparatus, in order to save power, a desalting chamber is divided into two small compartments divided by a cation exchange membrane on one side, an anion exchange membrane on the other side, and a middle ion exchange membrane in the center. A desalination chamber is filled with an ion exchanger, and the enrichment chambers are provided on both sides of the desalination chamber via the cation exchange membrane and the anion exchange membrane. It is preferable to adopt a structure that is arranged in a space. In particular, it is preferable that the desalting chamber is composed of a deionization module formed by laminating a cation exchange membrane, one frame, an intermediate ion exchange membrane, another frame, and an anion exchange membrane in this order. The intermediate ion exchange membrane can be composed of, for example, a cation exchange membrane or a composite membrane in which an anion exchange membrane is arranged at a front stage in a flow direction of water to be treated and a cation exchange membrane is arranged at a rear stage.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D006 GA17 HA41 HA47 KB01 KB11 MA03 MA13 MA14 MB07 PA02 PB07 PC32 4D061 DA05 DB13 EA09 EB01 EB04 EB13 EB17 EB20 EB22

Claims (7)

[Claims] 1. A desalting chamber between an anode and a cathode, which is separated by a cation exchange membrane and an anion exchange membrane and filled with an ion exchanger, and a concentration chamber for receiving ions moving from the desalting chamber. And a plurality of ion exchangers filled in the device with a volume fraction (cation exchanger / anion exchanger) of 2 or more. 2. A desalination chamber is formed by filling an ion exchanger into two small desalination chambers partitioned by a cation exchange membrane on one side, an anion exchange membrane on the other side, and a middle ion exchange membrane in the center. The electrodeionization apparatus according to claim 1, wherein concentration chambers are provided on both sides of the desalination chamber via the cation exchange membrane and the anion exchange membrane, and the desalination chamber and the concentration chamber are disposed between the anode and the cathode. apparatus. 3. A desalting chamber is formed by laminating a cation exchange membrane, one frame having a hollow inside, an intermediate ion exchange membrane, another frame having a hollow inside, and an anion exchange membrane in this order. The electrodeionization device according to claim 2, comprising a deionization module. 4. The electrodelizing device according to claim 2, wherein the intermediate ion exchange membrane is a cation exchange membrane or a double membrane in which an anion exchange membrane is arranged at a front stage in a flow direction of the water to be treated and a cation exchange membrane is arranged at a rear stage. Ion equipment. 5. The ion exchanger according to claim 1, wherein the ion exchanger through which the water to be treated is passed last in the desalting chamber is packed in a mixed bed form of an anion exchanger and a cation exchanger. Electrodeionization equipment. 6. The electrodeionization apparatus according to claim 1, which is used for condensate desalination in a pressurized water nuclear power plant. 7. A desalination treatment for blowdown water of a steam generator in a pressurized water nuclear power plant.
Electrodeionization equipment.