JP3226604B2 - Condensate desalination equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensate desalination apparatus comprising a condensate desalination tower and an ion exchange resin regenerating apparatus.

[0002]

2. Description of the Related Art In a boiling water nuclear power plant, in order to keep the inside of the reactor always clean, the condensate returned from the condenser of the turbine into the reactor is purified by a condensate desalination tower. After being highly purified, it is used as water supply to nuclear reactors.

Conventionally, as shown in the system configuration diagram of FIG. 4, steam generated in a reactor pressure vessel 1 is sent to a steam turbine 3 via a main steam pipe 2, and the power generated by the steam turbine 3 is rotated. The generator 4 is configured to generate power. In the condensate / water supply system, the steam that drives the steam turbine 3 is condensed in the condenser 5 to be condensed, and the low-pressure condensate pump 6
The water is pressurized, and the impurities are removed by a condensate filtration device 9 and a condensate desalination tower 10 in a condensate purification system via an air extractor 7 and a ground steam condenser 8.

The condensate purified by the condensate filtration device 9 and the condensate demineralization tower 10 is further pressurized by a high-pressure condensate pump 11 and sent to a low-pressure heater 12 where it is heated and supplied as a water supply pump.
The pressure is increased at 13 and the reactor pressure vessel 1
Refluxed inside. The turbine bleed air 15 is heated by the low-pressure heater 12 and the high-pressure heater 14, and then condensed into heater drain water. The heater drain water is sequentially sent to the low pressure side from the high pressure heater 14 to the low pressure heater 12, and is finally collected in the condenser 5.

The condensate desalination tower 10 has a built-in granular ion exchange resin and is configured to mainly remove ionic impurities in the condensate. When the capacity of the condensate desalination tower 10 is reduced, the condensate desalination tower in another standby state is newly added to the system, and the condensate desalination tower 10 is temporarily
Separate from the system and purify condensate continuously.

At this time, the condensate and desalination tower 10 whose capacity has been reduced has its internal ion exchange resin regenerated by a regenerator 16 forming a condensate demineralizer.
Until the regeneration of the ion exchange resin or the start-up of the plant, the water to be stored in the condensate desalination tower 10 is supplied from the condensate storage tank 17 at a lower temperature through the condensate makeup water pump 18. Has become.

[0007]

The conventional condensate desalination apparatus has the following problems. (1) Water for regeneration and storage of the ion-exchange resin uses low-temperature condensate from the condensate storage tank 17 to the condensate makeup water pump 18
However, since the condensate storage tank 16 is in communication with the atmosphere, the service water has a high dissolved oxygen concentration. It is a major cause. When the ion exchange resin is oxidatively degraded, total organic carbon (TOC) is generated from the resin matrix, and this total organic carbon is condensed in the condensate desalination tower 10.
Water quality at the exit of the river was degraded.

(2) The ionic components in the condensate which is the water to be treated in the condensate desalination tower 10 include strong ionic components (sodium) which are easily captured by the ion-exchange resin and greatly contribute to the increase in water conductivity. Ions, sulfate ions, etc.) and weak ion components (silica ions, etc.) which are not easily captured by the ion exchange resin and contribute little to the increase in water conductivity.

The desalination treatment in the condensate desalination apparatus for the water to be treated is performed as shown in FIG.
Is processed by I. In the initial stage of water passage, both the strong ion component ○ and the weak ion component × are captured, and the conductivity of the outlet water and the impurity ion component concentration are kept well below a predetermined value (A). In addition, from the selective adsorption property of the ion exchange resin, in the ion exchange resin layer 19,
The strong ion component ○ is captured on the inlet side and the weak ion component × is captured on the outlet side (B).

B. As the flow of the water to be treated is continued, the strong ion component ○ and the weak ion component × reach the ion exchange resin capture capacity limit (ion exchange capacity), and thereafter the weak ion component × cannot be trapped and exit The weak ion component x that has been trapped earlier is released as the water flows out into the water and the strong ion component 捕捉 is captured (C). For this reason, since the outlet water does not contain the strong ionic component ○, the conductivity is kept low, but the outlet water contains impurities of the weak ionic component x.

C. As the flow of water continues, the strong ionic component ○ reaches the ion exchange capacity (D), and thereafter, the strong ionic component ○ cannot be captured and flows out to the outlet water. , The impurity ion concentration cannot satisfy the predetermined value (E).

From the behavior of the ion component capturing function in the condensate desalination tower 10 described above, in the conventional condensate desalination apparatus, the conductivity of the outlet water is used as a control criterion at the time (D) in the ion exchange resin. Since the exchange or the regeneration with the chemical solution is performed, the ion component capturing operation is continued until the strong ion component reaches the ion exchange capacity. For this reason, the weak ion components are initially passed through the water (A) and (B). Except for (C), there is a problem that it becomes difficult to capture the water after (C) and flows out to outlet water.

(3) In recent years, from the viewpoint of improving water quality in power plants,
Attention has also been focused on capturing weak ion components,
The concentration of this weak ion component in the outlet water has also become a control standard. However, as for the weak ion component, the outflow starts from the early stage of the operation of the condensate desalination apparatus as described above (C). should Ru greatly increase the frequency of replacement or chemical regeneration of the ion-exchange resin, as a result, the secondary waste is increased.

An object of the present invention is to store heater drain water of a hot water having a low dissolved oxygen concentration in a water tank for regeneration, heat regeneration and storage of an ion exchange resin, and weak ion components trapped by the ion exchange resin. Supply during removal of
It is an object of the present invention to provide a condensate desalination apparatus which prevents oxidative deterioration of an ion exchange resin and reduces the amount of a regenerated chemical solution.

[0015]

SUMMARY OF THE INVENTION A condensate desalination tower for removing soluble impurities contained in condensate water, and a regenerating apparatus for regenerating a cation exchange resin and an anion exchange resin in the condensate desalination tower. In the condensate desalination apparatus provided, it is characterized in that hot water is supplied to water for regeneration and storage of the cation exchange resin and the anion exchange resin, and the hot water is heater drain water,
Store in the regeneration water tank.

[0016]

The water used for regenerating and storing the ion-exchange resin in the condensate desalination tower and the condensate desalination unit of the regenerator and for removing the trapped weak ion components, for example, turbine bleeding using a low-pressure heater and a high-pressure heater. Use condensed heater drain water.

This heater drain water is warm water having a low oxygen concentration and degassed in the condenser. Therefore, by flowing this warm water through the ion exchange resin during thermal regeneration, the weak ion components trapped by the ion exchange resin are easily removed. In addition, when stored after regeneration, since the water is low in dissolved oxygen, total organic carbon (TOC) from ion exchange resin
Is less eluting, oxidative degradation is prevented, and the frequency of ion exchange resin exchange and regeneration with a chemical solution is reduced, so that the amount of secondary waste generated is also reduced.

[0018]

An embodiment of the present invention will be described with reference to the drawings. The same components as those of the above-described conventional technology are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in the system configuration diagram of FIG. 1, in the main steam system, steam generated in a reactor pressure vessel 1 is sent to a steam turbine 3 via a main steam pipe 2, and a generator 4 is rotated by the steam turbine 3. It is configured to generate power.

In this condensate / water supply system, the steam that drives the steam turbine 3 is condensed in the condenser 5 to be condensed, and the condensed water is boosted by the low-pressure condensate pump 6 and the air extractor 7 and the ground steam condenser 8 The impurities are removed by a condensate filtration device 9 in the condensate purification system and a condensate desalination tower 10 containing a cation exchange resin and an anion exchange resin.

The condensed water purified by the condensate filtration device 9 and the condensate desalination tower 10 is further pressurized by a high-pressure condensate pump 11 in a condensate / water supply system, sent to a low-pressure heater 12, and heated. The water pressure is increased by a water supply pump 13 as water supply, and the water is supplied to the reactor pressure vessel 1 via a high pressure heater 14.

The low-pressure heater 12 and the high-pressure heater 14
The turbine bleed air 15 is supplied to the
Is heated by the low-pressure heater 12 and the high-pressure heater 14 and then condensed into heater drain water. This heater drain water is sequentially sent to the low pressure side from the high pressure heater 14 to the low pressure heater 12, and together with the heater drain water from the low pressure heater 12,
It is stored in the regeneration water tank 20 of the condensate desalination device.

The regenerating water tank 20 is connected to the condensate desalination tower 10 and the regenerator 16 via the condenser 5 and the regenerating water transfer pump 21. 5 and partly regenerate the ion-exchange resin as necessary, and use the condensate-desalination tower 10 as water for storing the ion-exchange resin in the condensate desalination tower 10 until the plant is started up. And the playback device 16.

Next, the operation of the above configuration will be described. The turbine bleed air 15 is condensed by the low-pressure heater 12 and the high-pressure heater 14 to become heater drain water. The heater drain water is sequentially sent from the high-pressure heater 14 to the low-pressure heater 14 on the low-pressure side, and is temporarily stored in the regeneration water tank 20. Since the dewatered water is first deaerated in the condenser 5, the oxygen concentration is low. The temperature is in a warm water state (about 50 to 60 ° C.).

Therefore, the regeneration of the ion exchange resin in the condensate desalination unit by the condensate desalination tower 10 and the regenerating unit 15 and storage after the regeneration until it is again incorporated into the condensate purification system, and As the water for removing the trapped weak ion components, the heater drain water of the warm water from the regeneration water tank 20 is used.

[0025] Figure 2 compares JP showing elution amount of total organic carbon (TOC) from the dissolved oxygen concentration and the ion exchange resin water
FIG. According to this, the elution amount of TOC is higher when the high-dissolved oxygen water shown by the open circle and the dotted line 23 is used than the low-dissolved oxygen water that is the deaerated water shown by the black circle and the solid line 22. It turns out that it is extremely large. Therefore, by using heater drain water of low dissolved oxygen water as service water, oxidative deterioration of the ion exchange resin can be prevented. It is also known that the ion exchange capacity of the ion exchange resin depends on the water passage temperature, and the ion exchange capacity decreases as the water passage temperature increases.

The present invention utilizes the temperature dependence of the ion exchange resin and temporarily passes low-dissolved oxygen warm water (heater drain) through the ion exchange resin which has approached the trapping capacity limit (ion exchange capacity). By reducing the ion exchange capacity, heat regeneration for releasing a part of the ion components trapped so far and prevention of oxidative deterioration are applied at the same time.

This heat regeneration method is characterized in that secondary waste such as used ion exchange resin and regenerated waste liquid is not generated, and silica is difficult to be trapped by the ion exchange resin due to the selectivity of the ion exchange resin. , Etc., can be selectively removed.

In this embodiment, a desalination process is performed as shown in the functional diagram of FIG. I. In the early stage of water passage, both the strong ion component ○ and the weak ion component × are captured, and the conductivity of the outlet water and the impurity ion component concentration are kept well below the predetermined values (A). Also, due to the selective adsorption of the ion exchange resin, in the ion exchange resin layer 19, a strong ion component に is captured on the inlet side and a weak ion component × is captured on the outlet side (B). As the state (B) is continued, the strong ion component ○ and the weak ion component × reach the ion exchange capacity of the ion exchange resin, and thereafter, the weak ion component × flows out to the outlet water. Become.

B. Here, the desalination process is temporarily interrupted, and the heater drain water, which is hot water stored in the regeneration water tank 20, is used as water, and the condensate desalination tower 10 and the regeneration device 15 of the condensate desalination device are supplied from the regeneration water transfer pump 21. And water. The temperature of the ion-exchange resin rises due to the hot water, and the exchange capacity apparently decreases, so that the ion components trapped so far cannot be retained, and the trapped ion components are released. At this time, the weak ion component X is selectively released due to the selectivity of the ion exchange resin (F).

C. When the heat regeneration is completed and the flow of the water to be treated is started, the temperature of the ion-exchange resin decreases, and accordingly, the ion-exchange capacity returns to the original level (G). D. When the desalting treatment is resumed after the completion of the thermal regeneration, the treatment capacity of the ion-exchange resin layer 19 is restored, and the strong ion component と and the weak ion component x are again subjected to the trapping treatment (H). E. When the ion exchange resin reaches the capture capacity limit (ion exchange capacity) again, the outflow of the weak ion component x starts (I). Here, the exchange of the ion exchange resin or the regeneration operation with a chemical solution is performed for the first time.

As described above, when the trapping capacity limit (ion exchange capacity) in the ion exchange resin layer 19 is reached (B), heat regeneration is performed using heater drain water of warm water, so that the weak ion component is obtained. Even in recent plants where the concentration is also used as a control standard, the frequency of ion exchange resin exchange or chemical solution regeneration is reduced, and the amount of secondary waste is reduced. In addition to regenerating the ion exchange resin,
It can be stored and reduced.

[0032]

[0033]

As described above, according to the present invention, the degassed service water having a low oxygen concentration is used for the regeneration and storage of the ion exchange resin. , All organic carbon (TO) to reactor pressure vessel
C) can be suppressed from flowing in, and the soundness of equipment in the reactor pressure vessel is improved.

Further, by performing thermal regeneration of the ion-exchange resin with hot water, the weak ionic components captured by the ion-exchange resin can be easily removed, and the frequency of the exchange of the ion-exchange resin or the regeneration of the chemical solution can be reduced. This has the effect of reducing the amount of secondary waste.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of one embodiment according to the present invention.

FIG. 2 is a graph showing the elution characteristics of total organic carbon from an ion exchange resin depending on the concentration of dissolved oxygen.

FIG. 3 is an explanatory diagram of a desalination process of one embodiment according to the present invention.

FIG. 4 is a system configuration diagram of a conventional condensate desalination apparatus.

FIG. 5 is an explanatory diagram of a desalination process in a conventional condensate desalination apparatus.

[Explanation of symbols]

5: condenser, 6: low pressure condensate pump, 9: condensate filtration device,
10 ... condensate desalination tower, 11 ... high pressure condensate pump, 12 ... low pressure heater, 13 ... feed water pump, 14 ... high pressure heater, 15 ... turbine extraction, 16 ... regenerator, 19 ... ion exchange resin layer, 20 ... regeneration Water tank, 21: Regeneration water transfer pump, 22: Low dissolved oxygen water (solid line), 23: High dissolved oxygen water (dotted line).

Continuation of front page (56) References JP-A-4-131181 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 49/00-49/02 C02F 1/42 G21F 9 / 12

Claims (1)

(57) [Claims] The condensate from a steam turbine condenser is atomized.
A condensate desalination tower installed in the condensate and water supply system that returns to the furnace to remove soluble impurities contained in the condensate water, and a cation exchange resin and an anion exchange resin in the condensate desalination tower In a condensate desalination apparatus provided with a regenerating device for regenerating, the water for regenerating and storing the cation exchange resin and the anion exchange resin is used.
Degassed by the condenser and installed in the condenser / water supply system.
Heater drain water heated by the heated heater
A condensate desalination apparatus comprising means for supplying a regenerator .