JP4367815B2 - Operation method of condensate demineralizer - Google Patents

Description

【００４７】
表１より、本発明によれば、濃アンモニア水により陽イオン交換樹脂と陰イオン交換樹脂の再生を行うことで、分離操作時の陰イオン交換樹脂中への陽イオン交換樹脂の混入がなく陰イオン交換樹脂のナトリウム分率が上昇しないため、従来の分離再生でのアンモニア型運転（つまり、酸・アルカリ再生処理を伴う運転）に比べ著しく良好な処理水を得ることができることが明らかになった。
【００４８】
【発明の効果】
以上説明したように、本発明の復水脱塩装置の運転方法によるときは、ＰＷＲ原子力発電所の復水処理系において、アンモニア型脱塩塔の運転と、限定したＨ−ＯＨ型脱塩塔の運転との併用とするとともに、アンモニア型脱塩塔のイオン交換樹脂の再生をアンモニア水のみで行うようにしたので、処理水質について蒸気発生器のＮａ水質管理基準値を満足させながら復水脱塩装置を主としてアンモニア型で運転することができ、復水脱塩装置全体に関してイオン交換樹脂の再生頻度を大幅に低減することができるとともに、硫酸イオン成分の放出を抑制して処理水質を向上することができる。再生頻度の低減により、使用するイオン交換樹脂の酸化劣化を抑えて樹脂の寿命を延長することができ、硫酸イオン成分放出の抑制により、ＰＷＲ原子力発電所での脱塩塔のアンモニア型運転を可能にするとともに、処理復水の水質を向上できる。
【図面の簡単な説明】
【図１】本発明の一実施態様に係る復水脱塩装置の運転方法を実施するための復水処理系の機器系統図である。
【図２】本発明に係るアンモニア型運転の効果を確認するために行った実験装置の機器系統図である。
【符号の説明】
１ 復水脱塩装置
２ 脱塩塔
５ 再生設備
６ 混合樹脂受入槽
７ カチオン再生塔
８ アニオン再生塔
２１ 予備塔
１０１ 脱塩塔カラム
１０２ 混合樹脂
１０３ 循環水タンク
１０４ 薬液タンク
１０５ ポンプ
１０６ 処理水路
１０７ 循環ポンプ
Ｖ₁ 、Ｖ₂ 、Ｖ₃ 弁[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for operating a condensate demineralizer, and in particular, when performing a condensate purification process in a secondary system of a pressurized water nuclear power plant (hereinafter sometimes abbreviated as a PWR nuclear power plant). The present invention relates to a method for operating a condensate demineralizer that can efficiently regenerate an ion exchange resin while improving water quality.
[0002]
[Prior art]
Conventionally, in the condensate treatment of a nuclear power plant, an H-OH type condensate demineralizer for treating condensate with a mixed resin of an H-type strongly acidic cation exchange resin and an OH-type strongly basic anion exchange resin has been used. It is used. In the condensate treatment of thermal power plants, NH _Four An ammonia-type condensate demineralizer that treats condensate with a mixed resin of a strongly acidic cation exchange resin and an OH-type anion exchange resin is used.
[0003]
In a nuclear power plant, generated high-temperature and high-pressure steam is supplied to a steam turbine, and the turbine is driven to generate power. The steam that has finished the work by driving the turbine is cooled by a condenser, returned to the water state, supplied to a boiler, a nuclear reactor, etc. while being heated again and recycled. The water cooled by the condenser is called condensate, but impurities such as iron oxide generated from the system such as steam pipes are mixed in this condensate, so it is purified by a condensate filtration device or a condensate demineralizer. Has been.
[0004]
Since the reactor internal structure of the nuclear power plant is stainless steel, and the capillary tube of the steam generator is a nickel alloy, stress corrosion cracking may occur due to alkali and acid components. For this reason, water quality management is particularly strict at nuclear power plants.
[0005]
It is necessary to avoid as much as possible the elution of corrosion factor components from the condensate demineralizer, which is a purification device, in terms of plant safety measures. For this reason, H-OH type condensate demineralizers are conventionally used in nuclear power plants.
[0006]
At the PWR nuclear power plant, in order to prevent corrosion of steam system piping and equipment, ammonia is added to the water in the secondary system to adjust to pH 9.2, and hydrazine is also added to perform deoxygenation treatment. Yes.
[0007]
In such an operation, when the pH is set to 9.2, the ammonia concentration is about 1 ppm. Therefore, when the condensate treatment is performed by the condensate demineralizer, the normal condensate demineralizer has a plurality of demineralizers. Since a tower is provided, it is necessary to perform a chemical regeneration process once every 10 days for one desalting tower. Since the number of desalting towers in a general power plant is 6 to 10, the regeneration is performed every 1 to 2 days.
[0008]
The strongly acidic cation exchange resin used in the condensate demineralizer is usually a sulfonated styrene-divinylbenzene copolymer. The base polymer is a stable material that is strong against acids, alkalis and organic solvents. However, this base polymer is no exception for the oxidative degradation that is the fate of organic polymer materials.
[0009]
These metals adhere to the cation exchange resin of the condensate demineralizer in order to remove iron, copper ions or oxides contained in the condensate. Also, hydrazine is adsorbed by ion exchange together with ammonia.
[0010]
Oxidation of the cation exchange resin is mainly caused by contact with water and air used in the regeneration operation. In particular, the influence of hydrogen peroxide generated by autooxidation of hydrazine in the presence of oxygen and metal. Is big. From the cation exchange resin, polystyrene sulfonic acid desorbed from the base polymer due to oxidative degradation is eluted. The eluted polystyrene sulfonic acid releases sulfate ions by thermal decomposition. For this reason, the polystyrene sulfonic acid which flowed out from the condensate demineralizer is thermally decomposed into a sulfate ion in the steam generator. It has been found that this sulfate ion has a great influence on the stress corrosion of the nickel-base alloy, and the degree of influence is higher than that of the chlorine ion. Therefore, in PWR nuclear power plants that use heat transfer tubes such as Inconel, which is a nickel-based alloy, for steam generators, the prevention of corrosion damage and the reduction of sulfate ions are one of the most important items for water quality management. ing.
[0011]
On the other hand, in the condensate demineralizer, a regeneration facility is provided in addition to the desalting tower in order to regenerate the ion exchange resin. For regeneration, use ion exchange resin, water and aerodynamic force to transfer from the desalting tower to the regeneration facility, physically remove and remove the deposits with the regeneration facility, and usually regenerate with acid / alkali and wash The ion exchange resin is again transferred from the regeneration facility to the desalting tower. The regenerated ion exchange resin transferred to the desalting tower is thoroughly mixed again in the desalting tower, washed, and then passed. Since ion exchange resins are repeatedly subjected to mechanical damage and chemical oxidation due to such regeneration operations, if the number of regenerations is large, the life of the resin will be shortened due to deterioration, or effluents will easily flow out when water flows immediately after regeneration. Therefore, various problems such as causing deterioration of water quality are generated.
[0012]
There are various measures to prevent oxidative degradation during regeneration, such as using nitrogen gas instead of air, but in order to reduce mechanical damage due to the regeneration operation itself and prevent water quality deterioration, the number of regenerations must be set. Reduction is the shortest way. As a method for reducing the number of regenerations, for example, a method of bypassing the condensate without treating the entire amount and reducing the amount of water passing through the desalting tower, an increase in the amount of cation exchange resin or ion exchange capacity, etc. However, the bypass water flow method requires special emergency operation when seawater leaks due to damage to the condenser heat transfer tube, and the design philosophy of the condensate demineralizer originally designed by treating the entire volume. Against. Moreover, the method by the increase in the amount of ion exchange resins has a limit from manufacturing cost and installation space.
[0013]
Therefore, as another method for reducing the number of regenerations, NH is applied to the condensate treatment of a thermal power plant. _Four An ammonia type operation in which condensate is treated with a mixed resin of a type cation exchange resin and an OH type anion exchange resin.
[0014]
However, the ammonia-type operation of the condensate demineralizer has not been used at the PWR nuclear power plant in spite of the fact that the water quality management of the plant is controlled by ammonia in the same way as the thermal power plant. Is a large amount of Na ions eluted due to the ion exchange equilibrium between the sodium fraction in the cation exchange resin after regeneration (molar fraction of Na-type exchange groups relative to all exchange groups) and the ammonia concentration in the condensate. This is because the Na water quality control standard value of the generator could not be satisfied.
[0015]
[Problems to be solved by the invention]
Therefore, the object of the present invention is to satisfy the Na water quality management standard value of the steam generator in order to reduce the number of times the ion exchange resin is regenerated and improve the quality of the treated water, particularly in the condensate treatment of the PWR nuclear power plant. It is another object of the present invention to provide a method for operating a condensate demineralizer that can be operated mainly in an ammonia type.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, a method for operating a condensate demineralization apparatus according to the present invention includes a plurality of demineralization towers filled with an ion exchange resin in which a cation exchange resin and an anion exchange resin are mixed. Pressurized water nuclear power plant Arbitrarily selected in the operation method of the condensate demineralizer that passes the condensate through the condensate demineralizer and performs the condensate treatment. Or 2 towers The demineralization tower of No. 1 is regenerated with acid and alkali repeatedly by performing H-OH type operation, and the other demineralization tower is ammonia type operation. Directly Dark Regeneration of both cation exchange resin and anion exchange resin with ammonia water The condensate treatment flow rate of one demineralization tower selected for the H-OH type is set smaller than the condensate treatment flow rate for any one of the demineralization towers selected for the ammonia type. It consists of the method characterized by doing.
[0017]
That is, the present invention is based on the following technical idea. The Na fraction of the cation exchange resin used in the ammonia type condensate demineralizer varies depending on the secondary system water quality management pH and the Na water quality management reference value of the steam generator. Generally, it is necessary that the Na fraction is 0.01% or less at pH = 9.2 and 0.001% or less at pH = 9.8. Similarly, the chloride ion (Cl) fraction of the anion exchange resin needs to be 0.1% or less and 0.01% or less.
[0018]
The required Na fraction and Cl fraction are extremely small, and are not normally achievable when regeneration is performed by a conventional method using a regeneration facility of a condensate demineralizer. Therefore, in order to achieve the required Na fraction, etc., a cation exchange resin or anion exchange resin in which the Na fraction and Cl fraction are reduced to below the target values in the production and purification stages of the ion exchange resin is used. For demineralization towers that are packed in the condensate demineralization tower and operate in the ammonia type, the used ion exchange resin is regenerated only with concentrated aqueous ammonia, without regenerating it with acid or alkaline chemicals such as hydrochloric acid or caustic soda. The method of the present invention utilizes this idea.
[0019]
In the conventional ammonia type condensate demineralizer, the ion exchange resin is regenerated by separating the cation and anion exchange resin in the regeneration facility in the same manner as the H-OH type condensate demineralizer, and then the cation exchange resin is sulfuric acid or Hydrochloric acid and anion exchange resin are regenerated with caustic soda. For this reason, mixing of the cation exchange resin into the anion exchange resin during the separation operation is unavoidable, and even if the chemicals are thoroughly washed, it is impossible to make the remaining acid / alkali zero. It is. For this reason, the Na fraction of the cation exchange resin rises and cannot be maintained below 0.001% when the regeneration is repeated. Especially in the PWR nuclear power plant, the ammonia type operation of the condensate demineralizer Can not be. In order to prevent the Na fraction of the cation exchange resin from increasing even if the regeneration is repeated, a small amount of Na adsorbed on the cation exchange resin is directly used for the regeneration. This is achieved by regenerating and removing ions, metal ions, and the like. At this time, it goes without saying that the anion exchange resin in the mixed resin can be regenerated with concentrated ammonia water.
[0020]
On the other hand, when all the demineralization towers of the condensate demineralizer are operated in the ammonia type, ammonia is not removed in the condensate demineralizer, so the hydrazine added to the secondary system as a deoxidizer decomposes and decomposes with ammonia. Therefore, if the plant operation is continued, the ammonia concentration of the secondary system increases, pH adjustment cannot be performed, and there is a problem that ammonia type operation in normal condensate treatment cannot be performed.
[0021]
As a method for removing ammonia from the plant secondary system and adjusting the pH, a steam generator blower is used to remove ammonia in systems other than the condensate demineralizer, such as an electric desalination apparatus and a reverse osmosis membrane apparatus. Although it can be considered to be installed in a down system, it is not preferable because it involves an increase in equipment and cost.
[0022]
In the present invention, the removal of ammonia from the secondary system without causing such an increase in equipment and cost, one or two of the condensate demineralization towers are not in an ammonia type operation, This is achieved by using the H-OH type operation. In other words, the ammonia in the condensate is adsorbed and removed by the demineralization tower that performs this H-OH type operation, and the cation exchange resin whose adsorption amount has reached saturation is regenerated by the regeneration facility, and the ammonia is removed and reused. To do. Here, the demineralization tower that continues the H-OH type operation, in principle, does not perform the ammonia type operation because the Na fraction in the cation exchange resin increases due to the regeneration, and the desalination is dedicated to the H-OH type operation. It must be limited as a tower.
[0023]
Thus, in the method according to the present invention, one or more of the condensate demineralization towers is limited to the operation of the H-OH type condensate demineralizer, and the remaining demineralization towers are ammonia type. The ion exchange resin of the desalting tower which is limited to the operation of the condensate demineralizer and performs the ammonia type operation is regenerated with concentrated ammonia water.
[0024]
Desalting towers operated in the ammonia type have a significantly reduced number of regenerations and are not regenerated as in the past (that is, regeneration with direct ammonia water), eliminating oxidative degradation of the cation exchange resin due to regeneration. This is a condensate demineralizer that does not generate eluate after regeneration and does not discharge sulfate ion components.
[0025]
In addition, the desalting tower operated in the H-OH type is usually designed to regenerate the chemical once every 10 days. Therefore, when the water flow rate of this H—OH type desalting tower is halved, for example, regeneration is performed once every 20 days, and the regeneration frequency can be greatly reduced. However, the amount of water flow is determined by the relationship between the pH of the secondary system, that is, the ammonia concentration and the amount of ammonia that needs to be removed. If the amount of ammonia due to the decomposition of hydrazine is small, the amount of water flow is further greatly reduced. can do.
[0026]
In addition, according to the method of the present invention, it is possible to cope with high pH water quality management in which the secondary system has a current pH of 9.2 or higher. The increase in pH increases the ammonia load on the H—OH type desalting tower, and the regeneration frequency becomes shorter than the conventional 10 days. However, the amount of water flow to the H—OH type desalting tower is reduced as described above. As a result, the reproduction frequency (reproduction cycle) can be extended.
[0027]
As described above, in the method according to the present invention, by first filling the ion exchange resin having a low Na fraction and Cl fraction and operating, the Na water quality management standard value of the steam generator can be basically satisfied. it can. The demineralization tower that performs the ammonia type operation has a significantly reduced number of regenerations compared to the conventional method, and is regenerated only with concentrated ammonia water. The service life is greatly extended, and a condensate demineralizer without release of sulfate ion components is obtained. In addition, the number of desalting towers operating in the H-OH type is reduced to 1/3 to 1/10 of the conventional one (for example, 2 of 6 towers to 1 of 10 towers), Since the frequency of regeneration can be greatly reduced by adjusting (reducing) the water flow rate, the release of sulfate ion components that occur every time regeneration is greatly reduced. In addition, since the number of regenerations is greatly reduced, the oxidative deterioration of the cation exchange resin due to regeneration is prevented, and there is an advantage that the resin life is greatly extended. As a result, as the entire condensate demineralization apparatus, the regeneration frequency, regeneration amount, and replacement amount of the ion exchange resin are greatly reduced, and the quality of the treated water is improved.
[0028]
In the operation method of the condensate demineralizer according to the present invention, it is desirable to take the following considerations. The case where seawater leaks from the condenser and seawater enters the condensate is called seawater leak. However, when seawater leak occurs, the load on the ion exchange resin for Na ion and Cl ion increases. Since the Na fraction and the Cl fraction are increased, the condensate demineralizer cannot continue the ammonia type operation for a long time. For this reason, in general, when seawater leaks occur in the ammonia type condensate demineralizer, it is necessary to quickly switch to H-OH type operation, and when seawater leaks disappear, return to ammonia type operation again. It is normal to do. However, in the condensate demineralization apparatus of the PWR nuclear power plant which is the subject of the present invention, it is necessary to keep the treated water quality very high. Even if it switches to mold operation, it cannot return to ammonia type operation again. When the ammonia type operation is performed again, it is necessary to newly prepare and fill cation and anion exchange resins having a Na fraction of 0.001% or less and a Cl fraction of 0.1% or less.
[0029]
If seawater leaks when the water quality of the secondary system is being controlled at a high pH of 9.2 or higher, Na will likely leak from the desalting tower even if the Na fraction increases slightly. It is necessary to lower the pH of the secondary system as soon as possible. In order to lower the pH, it is necessary to stop the injection of ammonia added for adjustment to the secondary system, and increase the number of H-OH type desalting towers to increase the amount of ammonia removed. For this purpose, for example, it is preferable to store the ion exchange resin used for the H—OH type operation in a regeneration facility or a preparatory tower and quickly replace it with the ion exchange resin of the ammonia type desalting tower when seawater leak occurs. .
[0030]
In addition, since the ion exchange resin of the desalting tower that has been subjected to the ammonia type operation is not regenerated by the conventional method as described above, it is difficult to undergo oxidative degradation and has a long life. However, if the Na fraction in the resin increases with long-term use and ammonia type operation becomes impossible, the Na fraction can be reduced to 0.001% or less by special regeneration equipment, or reused. Since the resin of the demineralization tower used in the H-OH type needs to be replaced periodically due to oxidative degradation and the exchange frequency is higher than that of the ammonia type operation resin, the ion exchange resin used in the ammonia type demineralization tower is H. It can also be used as a resin for —OH type desalting tower. In the latter case, the ion exchange resin having a high Na fraction used in the ammonia type desalting tower may be regenerated with an acid / alkali, and then charged into the H-OH type desalting tower.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a condensate purification system for carrying out a method of operating a condensate demineralizer according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a condensate demineralizer having a plurality of demineralizers 2, and performs demineralization treatment of condensate fed from a condenser not shown. Each desalting tower 2 is filled with an ion exchange resin in which a cation exchange resin and an anion exchange resin are mixed. Among these, one or more optional desalting towers 2 (the desalting tower in FIG. 1) are selected. In d), H-OH type operation is performed, and the used ion exchange resin is regenerated with acid and alkali repeatedly. The remaining desalting tower 2 (desalting towers a, b and c in FIG. 1) is operated in an ammonia type, and the used ion exchange resin is directly regenerated with ammonia water, particularly concentrated ammonia water.
[0032]
Condensate from the condenser is sent to each desalting tower 2 via the line 3 and circulated to the steam generator via the line 4 after the desalting treatment.
[0033]
Reference numeral 5 denotes an ion exchange resin regeneration facility. In this embodiment, the regeneration facility 5 includes a mixed resin receiving tank 6, a cation regeneration tower 7, and an anion regeneration tower 8.
[0034]
The ion exchange resin used in the demineralization towers 2a, 2b, and 2c that perform the ammonia type operation is transferred to the cation regeneration tower 7 via the line 10 by opening one of the demineralization tower outlet valves 9. Concentrated aqueous ammonia is fed to the cation regeneration tower 7 and regenerated without using an alkali such as acid or caustic soda. The regenerated ion exchange resin is returned to one of the desalting towers 2a, 2b, and 2c via the line 13 by opening the valve 11 and one of the desalting tower inlet valves 12.
[0035]
The used ion exchange resin from the desalting tower 2d of the H-OH type operation is sent to the mixed resin receiving tank 6 once by opening the desalting tower outlet valve 14 and the receiving tank inlet valve 15, and into the tank 6 Together with the remaining mixed resin, it is once accommodated in the mixed resin receiving tank 6. From the mixed resin receiving tank 6, the valve 16 is opened and sent to the cation regeneration tower 7, where the cation exchange resin and the anion exchange resin are separated, and the upper layer side is an anion exchange resin and the lower layer side is a cation exchange resin. Become. At this time, an incompletely separated mixed resin layer remains at the boundary portion between the upper anion exchange resin and the lower cation exchange resin. The separated anion exchange resin is opened to the valve 17 and sent to the anion regeneration tower 8 via the line 18, and the mixed resin of the incomplete separation resin layer located above the cation exchange resin layer is connected to the line 22. Then, it is returned to the mixed resin receiving tank 6 to be ready for receiving the next recycling resin. On the other hand, the lower layer cation exchange resin remains in the cation regeneration tower 7. In this state, acid is injected into the cation regeneration tower 7 to regenerate the cation exchange resin, and caustic soda (alkali) is injected into the anion regeneration tower 8 to regenerate the anion exchange resin. The regenerated anion exchange resin is opened to the valve 19 and sent to the cation regeneration tower 7 via the line 20, mixed with the regenerated cation exchange resin, and then returned to the desalting tower 2 d via the line 12. It is.
[0036]
In any of the ammonia type desalting towers 2a, b, c and H-OH type desalting towers 2d, the regenerated ion exchange resin is transferred from the cation regeneration tower 7, so that the ammonia type desalting tower The ion exchange resin used in the tower can be regenerated and transferred to the H-OH type desalting tower 2d and packed.
[0037]
In this embodiment, the condensate treatment flow rate of one H-OH type desalting tower 2d is set to be smaller than the condensate treatment flow rate of one ammonia type desalting tower 2a, b, c. .
[0038]
Furthermore, in this embodiment, a preliminary tower 21 is provided in which a standby resin of a mixed ion exchange resin of a cation exchange resin and an anion exchange resin is waiting and filled. The preliminary tower 21 is filled with an ion exchange resin for one H-OH type desalting tower, and is provided in an emergency such as seawater leak as described above.
[0039]
In such a condensate treatment system of the PWR nuclear power plant, for example, a cation exchange resin having a Na fraction of 0.01% or less and an anion exchange resin having a Cl fraction of 0.1% or less are used as a desalting tower 2a, The ammonia type operation is performed by filling b and c, and the regeneration is performed with concentrated aqueous ammonia. Further, one or more demineralization towers 2d are limited, and only the demineralization tower 2d is subjected to H-OH type operation and regenerated with a normal acid / alkali.
[0040]
The desalting towers 2a, 2b, and 2c that perform ammonia-type operation have a significantly reduced number of regenerations compared to the conventional method, and because regeneration is performed only with concentrated ammonia water, there is little oxidative degradation of the ion exchange resin, The service life of the ion exchange resin is greatly extended, and a condensate demineralization tower without release of sulfate ion components is obtained. Since the number of desalting towers 2d operated in the H-OH type is reduced to 1/3 to 1/10 of the conventional one, the release of sulfate ion components is also suppressed in proportion to the number of towers, and the quality of treated water is improved. While improving, the ion exchange resin exchange amount is also reduced to 1/3 to 1/10. In addition, the frequency of regeneration is also reduced by adjusting (reducing) the amount of water flow.
[0041]
Further, the ion exchange resin waiting in the standby tower 21 enables a quick response even when seawater leaks.
[0042]
In order to confirm the effect of performing the regeneration treatment of the ion exchange resin directly with ammonia water in the operation method of the condensate demineralization apparatus according to the present invention as described above, the following comparative test was performed ( Example 1 and Comparative Example 1).
[0043]
Example 1
Water was passed through the desalting tower column 101 using the apparatus shown in FIG. In the desalting tower column 101, a cation exchange resin with a Na fraction adjusted to 0.001% and an anion exchange resin with a Cl fraction adjusted to 0.1% were mixed at a resin ratio of 2: 1 and packed. (Mixed resin 102). To the flowing water stored in the circulating water tank 103, ammonia 540 μg / L, hydrazine 250 μg / L, and sodium ion 10 ng / L are added from the chemical liquid tank 104 to the pure water through the pump 105 to adjust the pH to 9.2. The obtained liquid was used. Further, the treatment water channel 106 is connected to the circulation pump 107 and each valve V. ₁ , V ₂ , V _Three The water flow rate was 80 m / hr.
[0044]
For the first water flow cycle as a preliminary cycle, the water flow is terminated when ammonia begins to leak into the treated water, and both ions are separated without separating the resin into a cation exchange resin and an anion exchange resin. The mixture was regenerated with 12% aqueous ammonia with the exchange resin mixed. The regenerated resin was charged again into the desalting tower column 101 and mixed, and water was passed through. In the second water cycle, water flow was continued in a state where ammonia leaked into the treated water, and the treated water was analyzed in order to see the water flow result of this ammonia type operation tower. The analysis of the treated water was performed with an ion chromatograph after the organic components were subjected to ultraviolet decomposition with an ultraviolet irradiation device. The results are shown in Table 1.
[0045]
Comparative Example 1
Water was passed through the desalting tower column 101 using the apparatus shown in FIG. The packing resin, resin ratio, water flow rate, and water flow rate of the desalting tower column 101 were the same as in Example 1. As in Example 1, the first water cycle was terminated when ammonia leaked, and then the cation exchange resin and the anion exchange resin were separated. The cation exchange resin was 7% hydrochloric acid, The ion exchange resin was regenerated with 7% caustic soda, and then charged again into the desalting tower column, mixed and passed through. In the second water cycle, water flow was continued even after the cation exchange resin was saturated with ammonium ions and an ammonia break occurred, and the treated water at that time was analyzed. Analysis of treated water after the ammonia break was the same as in Example 1. The results are shown in Table 1.
[0046]
[Table 1]

[0047]
From Table 1, according to the present invention, the cation exchange resin and the anion exchange resin are regenerated with concentrated aqueous ammonia, so that the anion exchange resin is not mixed into the anion exchange resin during the separation operation. Since the sodium fraction of the ion exchange resin does not increase, it became clear that significantly better treated water can be obtained compared to the ammonia type operation in the conventional separation regeneration (that is, the operation with acid / alkali regeneration treatment). .
[0048]
【The invention's effect】
As described above, when the operation method of the condensate demineralization apparatus of the present invention is used, in the condensate treatment system of the PWR nuclear power plant, the operation of the ammonia type demineralization tower and the limited H—OH type demineralization tower In addition, the regeneration of the ion exchange resin of the ammonia-type desalting tower is performed only with ammonia water, so that the condensate dewatering is performed while satisfying the Na water quality management standard value of the steam generator for the treated water quality. The salt device can be operated mainly in the ammonia type, and the regeneration frequency of the ion exchange resin can be greatly reduced with respect to the entire condensate demineralizer, and the treated water quality is improved by suppressing the release of sulfate ion components. be able to. By reducing the frequency of regeneration, the oxidative deterioration of the ion exchange resin used can be suppressed and the life of the resin can be extended. By suppressing the release of sulfate ion components, the ammonia-type operation of the desalting tower at the PWR nuclear power plant is possible. In addition, the quality of the treated condensate can be improved.
[Brief description of the drawings]
FIG. 1 is an equipment system diagram of a condensate treatment system for carrying out a method of operating a condensate demineralizer according to an embodiment of the present invention.
FIG. 2 is an equipment system diagram of an experimental apparatus conducted for confirming the effect of ammonia-type operation according to the present invention.
[Explanation of symbols]
1 Condensate demineralizer
2 Demineralization tower
5 reproduction facilities
6 Mixed resin receiving tank
7 Cation regeneration tower
8 Anion regeneration tower
21 Reserve tower
101 Desalting tower column
102 Mixed resin
103 Circulating water tank
104 Chemical tank
105 pump
106 treatment channel
107 Circulation pump
V ₁ , V ₂ , V _Three valve

Claims (3)

Condensate treatment is performed by passing condensate through a condensate demineralizer of a pressurized water nuclear power plant equipped with multiple demineralization towers filled with an ion exchange resin mixed with a cation exchange resin and an anion exchange resin. In the operation method of the condensate demineralization apparatus, one or two arbitrarily selected demineralization towers are H-OH-typed and regenerated with acid and alkali repeatedly. Performs the ammonia type operation, and for the desalting tower that has performed the ammonia type operation, both the cation exchange resin and the anion exchange resin are directly regenerated with concentrated aqueous ammonia and selected as the H-OH type. A condensate demineralization characterized in that the condensate treatment flow rate of one demineralization tower is set smaller than the condensate treatment flow rate of any one of the demineralization towers selected for the ammonia type. How to operate the device. Upon exchanging the ion exchange resin demineralizer performing the ammonia-type operation, characterized in reusing the spent ion exchange resin as H-OH type ion exchange resin for demineralization tower, according to claim 1 Operation method of condensate demineralizer. The operation method of the condensate demineralizer according to claim 1 or 2 , wherein one column for the H-OH type demineralization tower is stored as a preparatory resin for the mixed ion exchange resin.

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