JP2019060630A - Method for measuring conductivity of decationized water and measurement system - Google Patents

Abstract

To provide a method for measuring the conductivity of decationized water, the decationization efficiency of which is high and the load of which on a device is small.SOLUTION: Diluted water is added to the water to be processed that includes cations and anions, and the diluted water to be processed having had its pH lowered is generated. Then, this diluted water to be processed is supplied to a decationizing device 3 and decationized water is generated. Then, the decationized water generated by the decationizing device 3 is supplied to a conductivity meter 4 and the conductivity of the decationized water is measured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and system for measuring the conductivity of decationized water, and more particularly to a method for measuring the conductivity of condensate in a power plant.

  In thermal power plants and nuclear power plants (hereinafter referred to as power plants), high-temperature, high-pressure steam generated by steam generation means such as a boiler is introduced to a steam turbine, and exhaust steam discharged from the steam turbine is Water circulation is performed in which the water is condensed to be condensed, and the condensed water is supplied to the steam generation means as water supply. Since impurities such as corrosion products accumulate in the condensate, the power plant is equipped with a condensate demineralizer that removes these impurities from the condensate during steady operation. When the condenser is a seawater cooling system, the condensate demineralizer also has a function to capture sodium chloride etc. contained in seawater that may be mixed in the condensate for a certain period of time to protect the condensate system. There is. However, when seawater in excess of a certain amount flows in, it exceeds the operation allowable range of the condensate demineralizer, so the power plant is provided with a conductivity meter for the purpose of detecting the seawater component in the condensate. .

  On the other hand, in a power plant, in order to suppress corrosion of piping etc. of a condensate system, pH control agents such as ammonia are added to condensate to make the condensate alkaline. For this reason, the condensate has a low specific resistance and a high conductivity, and even if a small amount of seawater is mixed in the condensate, the change in the specific resistance or the conductivity is small. Therefore, it is difficult to detect mixing of seawater with a conductivity meter accurately. In order to solve this problem, a method may be taken in which cations such as ammonia are previously removed by a decationization apparatus, and condensed water with reduced conductivity is supplied to a conductivity meter (Patent Documents 1 and 2) . According to this method, detection accuracy of anions derived from seawater can be enhanced, and mixing of seawater can be detected with high accuracy.

Patent No. 4671272 Patent 3704289 gazette

  The pH of the condensate has been conventionally about 8.5 to 9.8, but it may be operated at a value exceeding 10 in recent years with the revision of JIS B 8223 "water quality of boiler feed water and boiler water". Along with this, the addition amount of ammonia which is a pH adjusting agent is increased, and the load of the decationizing apparatus is also increased. In the decationization apparatus using a cation exchange resin, the time to reach the through flow capacity is shortened, and more frequent exchange of the cation exchange resin and chemical regeneration are required. In the case of the electric regenerative decationization apparatus, this problem does not occur, but the current value is insufficient and ammonia and the like can not be sufficiently removed. In addition, when the current value is increased, the deterioration of the device is accelerated.

  An object of the present invention is to provide a method and a system for measuring the conductivity of decationized water having a high decationization efficiency and a small load on the apparatus.

  According to one aspect of the present invention, a method of measuring conductivity of decationized water comprises adding diluted water to treated water containing cations and anions to produce diluted treated water having a lowered pH. , Supplying the diluted treated water to the decationizing apparatus to form decationizing water, and supplying the decationizing water generated by the decationizing apparatus to the conductivity meter to remove Measuring the conductivity of the cationic water. Further, according to one aspect of the present invention, a system for measuring conductivity of decationized water comprises adding diluted water to treated water containing cations and anions to lower the pH of the diluted treated water. And a decationizing device for producing decationized water from diluted treated water, and a conductivity meter for measuring the conductivity of the decationized water produced by the decationizing device. .

  According to the present invention, it is possible to provide a method and a system for measuring the conductivity of decationized water with high decationization efficiency and small load on the apparatus.

It is a conceptual diagram of the conductivity measurement system of decationic ion water concerning a 1st embodiment of the present invention. It is a conceptual diagram of the conductivity measurement system of decationic ion water concerning a 2nd embodiment of the present invention. It is a conceptual diagram of the conductivity measurement system of decationic ion water concerning a 3rd embodiment of the present invention.

  Hereinafter, some embodiments of the present invention will be described with reference to the drawings. In each embodiment, the water to be treated is a condensate of a thermal power plant or a nuclear power plant. That is, the measurement system of the conductivity in each embodiment of the present invention is a system with which a thermal power plant or a nuclear power plant is provided. However, the present invention is not limited thereto, and can be applied to a method and system for measuring the conductivity of decationized water produced by the decationization apparatus.

First Embodiment
FIG. 1 shows a conceptual view of a decationized water conductivity measuring system 1 (hereinafter referred to as a system 1) according to a first embodiment of the present invention. The system 1 comprises a decationizing device 3, a conductivity meter 4, a flow meter 2 and a valve 7. These devices are installed on the pipe 6 branched from the condensate pipe 8. The outlet of the conductivity meter 4 is connected to the drain pipe 9. The system 1 also comprises a dilution device 10. The dilution device 10 has a dilution water supply line 11 branched from the drain pipe 9 and connected to the pipe 6, a transfer pump 12 provided on the dilution water supply line 11, a valve 13, and a flow meter 14. The condensed water supplied from the condensed water pipe 8 is diluted by the dilution water supplied from the dilution device 10 to be diluted treated water. The decationization apparatus 3 generates decationized water from diluted treated water containing cations and anions. The conductivity meter 4 measures the conductivity of the decationized water produced by the decationization apparatus 3. The flow meter 2 measures the flow rate of the diluted treated water flowing into the decationizing apparatus 3. The valve 7 is normally open but closed when it is necessary to isolate the system 1 from the condensate system.

  The decationizing apparatus 3 has a deionization chamber 31 and a pair of concentration chambers 32 and 33 disposed on both sides of the deionization chamber 31 with cation exchange membranes 34 and 35 interposed therebetween. The positive electrode 36 is disposed in the concentration chamber 32, the negative electrode 37 is disposed in the concentration chamber 33, and the concentration chambers 32 and 33 double as electrode chambers. The positive electrode 36 and the negative electrode 37 are connected to a DC power supply 38. The deionization chamber 31 is filled with a cation exchanger 39. The constitution of the cation exchanger 39 is not limited as long as it can capture and remove the cation component, but a cation exchange resin or monolithic porous cation exchanger (hereinafter simply referred to as "monolith"), fibrous porous cation exchanger A particle aggregation type porous ion exchanger can be suitably used.

  The monolith has an open cell structure having mesopores having an average diameter of 1 to 1000 μm, preferably 10 to 100 μm in the macropores and macropores connected to each other, and the total pore volume is preferably 1 to 50 ml / g, Is 4 to 20 ml / g, and ion exchange groups are uniformly distributed, and those having an ion exchange capacity of 0.5 mg equivalent / g dry porous body or more can be mentioned. The other physical properties of the monolith and the method for producing the same are disclosed, for example, in JP-A-2003-334560.

  By using a monolith as a cation exchanger, the pore volume and the specific surface area can be significantly increased. For this reason, the deionization efficiency of the electrodeionization apparatus is remarkably improved, which is very advantageous. In addition, if the total pore volume of the monolith is less than 1 ml / g, the amount of water flow per unit cross-sectional area becomes small, and the processing capacity is unfavorably reduced. On the other hand, when the total pore volume exceeds 50 ml / g, the proportion of the skeleton portion is reduced, and the strength of the porous body is significantly reduced. When a monolith having a total pore volume of 1 to 50 ml / g is used as an ion exchanger of the electrodeionization apparatus of electric regeneration type, it is possible to satisfy both the strength and the deionization efficiency of the porous body. Preferred. In addition, if the ion exchange capacity of the monolith is less than 0.5 mg equivalent / g dry porous material, the ion adsorption capacity is not sufficient, which is not preferable. In addition, if the distribution of the ion exchange groups is not uniform, the ion transfer within the porous cation exchanger becomes uneven, which is not preferable because the rapid elimination of the adsorbed ions is inhibited.

  As fibrous porous ion exchangers, for example, woven fabrics and non-woven fabrics which are single fibers and aggregates of single fibers described in JP-A-5-64726, and ions of the processed products using radiation graft polymerization. What introduce | transduced the exchange group and processed and formed is mentioned. Further, as the particle aggregation type porous ion exchanger, for example, a mixed polymer of a thermoplastic polymer and a thermosetting polymer described in JP-A-10-192716 and JP-A-10-192717, or a crosslinkable polymer is used. And ion-exchange resin particles bonded and processed.

The decationization apparatus 3 of the present embodiment is an electroregenerative decationization apparatus (EDI). In EDI, at the same time the cation component (Na ⁺ , Ca ²⁺ , Mg ²⁺ etc.) is captured by the cation exchanger 39, the dissociation reaction of water occurs in the deionization chamber 31 and hydrogen ions and hydroxide ions Occur. The cation component trapped in the cation exchanger 39 is exchanged with hydrogen ions and released from the cation exchanger 39. The liberated cation component travels along the cation exchanger 39 and is electrophoresed to the cation exchange membrane 35 on the negative electrode 37 side, and electrodialyzed by the cation exchange membrane 35 to move to the concentration chamber 33. The cation component transferred to the concentration chamber 33 is discharged together with the concentrated water flowing in the concentration chamber 33. After the exchange group of the cation exchanger 39 binds to the cation component, it liberates the cation component to recombine with hydrogen ions, so that the cation exchanger 39 is continuously regenerated. As described above, in the EDI, since the removal of the cation component and the regeneration of the cation exchanger 39 are performed automatically and continuously, the regeneration of the cation exchanger 39 basically does not have to be performed in a separate step. The decationizing device 3 is not limited to EDI, and may be an electrodialysis device (ED) in which the cation exchanger 39 is not filled. Moreover, the decationization apparatus 3 may be a cation exchange column filled with a cation exchange resin. When the water exchange load reaches the exchange capacity, the cation exchange column is regenerated with a chemical such as hydrochloric acid to regenerate the removal performance of the cation component (cation) contained in the diluted treated water.

  Hereinafter, an operation method of the system 1 will be described. During operation of the power plant, condensed water is flowing through the condensed water pipe 8. The valve 7 is opened and condensed water is introduced into the decationizing apparatus 3 through the pipe 6. In addition, decationized water discharged from the conductivity meter 4 is supplied to the pipe 6 through the transfer pump 12, the valve 13, and the flow meter 14. Therefore, the condensate (to-be-treated water) supplied from the condensate pipe 8 is diluted with decationized water to be diluted to-be-treated water. The flow rate of the diluted treated water introduced into the decationizing apparatus 3 is measured by the flow meter 2 installed upstream of the decationizing apparatus 3.

Ammonia and hydrazine are contained in the condensate (water to be treated) in order to prevent the corrosion of the piping and equipment of the condensate system. These are pH adjusters added to condensate to adjust the pH of the condensate. The pH of the condensed water is about 8.5 (1 mg / L of ammonia) to 9.8 (5 mg / L of ammonia) in the conventional thermal power plant, but may be operated at 10 or more in recent years. Ammonia is usually present in the condensate in the form of NH ⁺ or NH ₃ . The cations in the water to be treated are trapped by the cation exchanger 39 of the decationizing apparatus 3 and discharged through the cation exchange membrane 35 to the concentration chamber 33 on the negative electrode 37 side. The treated water from which the cation component has been removed by the decationization apparatus 3 is almost in the state of pure water. For this reason, the conductivity of the treated water measured by the conductivity meter 4 is 0.1 μS / cm or less.

There is a possibility that seawater may be mixed in the condensate system connected to the seawater cooling type condenser. That is, since the steam side is depressurized in the condenser, if a pinhole etc. occur in the capillary through which the seawater in the condenser flows, seawater intrudes from the capillary from the capillary to the vapor side, and the salt concentration of the condensate significantly increases Do. Examples of salts contained in seawater include NaCl, Na ₂ SO _{4 and the} like. When the condensed water mixed with these salts is introduced into the decationizing apparatus 3, Na ⁺ is trapped by the cation exchanger 39, and the treated water containing Cl ⁻ , SO ₄ ^{−2 and the} like is removed from the decationizing apparatus 3. Exhausted. The conductivity meter 4 detects HCl and H ₂ SO ₄ . For this reason, the conductivity of the treated water measured by the conductivity meter 4 becomes a value larger than usual (for example, 0.1 μS / cm or more). As described above, it is possible to detect the contamination of the seawater into the condensate by measuring the conductivity of the treated water containing almost all cations and containing anions derived from seawater such as chloride ions with the conductivity meter 4 it can. Such conductivity meter 4 may be called an acid conductivity meter.

  As described above, when the pH of the water to be treated is high, the load on the decationizing apparatus 3 is high. When the decationizing apparatus 3 is EDI, since the cation exchanger is regenerated continuously, chemical regeneration of the cation exchanger is unnecessary even if the load is high. However, since there are many cations to be removed, the current is insufficient, and the cations can not be removed in a short time. Increasing the voltage to increase the current may accelerate the degradation of the decationization device 3. There is a similar problem with ED. In the case of a cation deionization tower, the frequency of replacement and regeneration of the resin is increased because the cation exchange resin is quickly saturated.

  On the other hand, in the present embodiment, the condensed water introduced from the condensed water pipe 8 is diluted with decationized water, so it is possible to suppress an increase in the load of cations in the decationization apparatus 3. For example, when the pH of the pure water dilution of ammonia is 9.7 (hereinafter referred to as a comparative example), the concentration of ammonia is 0.9 mg / L, and when the pH is 10.3, the concentration of ammonia is 3 It becomes .6 mg / L and increases 4 times. Therefore, if the condensed water having a pH of 10.3 is diluted four times, and if the flow rate of the diluted treated water supplied to the decationizing apparatus 3 is equal to that of the comparative example, the load of the decationizing apparatus 3 is It will be almost the same as the load when treating the condensate of the comparative example. In this case, the opening degree of the valves 7 and 13 may be adjusted so that the ratio of the flow rate of the condensate introduced from the condensate pipe 8 to the flow rate of the dilution water is 1: 3. The opening degree of the valves 7 and 13 can be controlled based on the measurement values of the flow meters 2 and 14. The ratio of the flow rates can also be adjusted by adjusting the output of the transfer pump 12. Of the decationized water discharged from conductivity meter 4, about 1/2 to 3/4 of the whole is used as dilution water, and the remaining decationized water is used as electrode water and as concentrated water Discarded. In the case of the above example, the flow rate of the diluted treated water to be supplied to the decationization apparatus 3 is desirably about the same as that of the comparative example, but may be smaller than that of the comparative example. The allowable flow rate of the conductivity meter 4 has a certain range, and there is no problem even if the flow rate of the diluted treated water supplied to the decationization apparatus 3 is reduced relative to the comparative example within the allowable flow rate range. When the flow rate of the diluted treated water supplied to the decationizing apparatus 3 is reduced as compared with the comparative example, it is desirable to confirm whether or not the decationizing apparatus 3 has a polarized flow.

Although the concentration of detection target ions (Cl ^- ions etc.) contained in the diluted treated water supplied to conductivity meter 4 is smaller than that of the comparative example by dilution, the sensitivity of conductivity meter 4 is sufficiently high, so that the seawater leaks. It is possible to ensure the sensitivity required for the detection of For example, when NaCl having a concentration of 100 μg / L is mixed in with condensate due to seawater leakage, the conductivity detected by conductivity meter 4 of the condensate before being diluted (conductivity as decationized and detected as HCl) ) Is 0.73 μS / cm. Even when diluted by a factor of 5, the conductivity of the diluted treated water is 0.16 μS / cm, which can be sufficiently measured by the existing conductivity meter.

  As the dilution water, it is preferable to use the drainage of the conductivity meter 4 from the viewpoint of minimizing additional equipment, but pure water supplied from a pure water supply system of a power plant, for example, may be used. The dilution water preferably contains as little cation as possible, but it may be water having a cation concentration lower than that of the water to be treated (water having a low cation concentration).

Second Embodiment
FIG. 2 shows a conceptual view of a decationized water conductivity measuring system 101 (hereinafter referred to as a system 101) according to a second embodiment of the present invention. In the following description, configurations different from the first embodiment will be mainly described. The second embodiment has the dilution device 10 omitted from the first embodiment. That is, only by throttling the flow rate of the water to be treated, the amount of cations supplied to the decationizing apparatus 3 can be suppressed. In this case, the flow rate of deionized water supplied to the conductivity meter 4 also decreases. When the flow rate decreases, it is desirable to confirm whether or not the decationization device 3 has a drift. The flow rate is desirably equal to or higher than the minimum allowable flow rate of the conductivity meter 4, and when below the minimum allowable flow rate, it is desirable to change the conductivity meter 4 to a minute flow rate type. In the present embodiment, the valve 7 is used to reduce the flow rate, but any flow path resistance member can be used as long as the purpose is achieved. That is, the flow path resistance member is not limited as long as the pressure resistance is larger than the upstream and downstream sides of the flow path resistive member, for example, the flow path cross section is narrowed from the upstream and downstream sides of the orifice The roughness or unevenness of the wall surface may be larger than the upstream and downstream sides, or may be a curved pipe such as an elbow.

Third Embodiment
FIG. 3 shows a conceptual view of a decationized water conductivity measuring system 201 (hereinafter referred to as a system 201) according to a second embodiment of the present invention. In the following description, configurations different from the first embodiment will be mainly described. About the structure which abbreviate | omitted description, it is the same as that of 1st Embodiment. A heating means 15 for heating the water to be treated is provided on the pipe 6. The structure of the heating means 15 is not specifically limited, A heat exchanger, a ribbon heater, etc. can be used. The temperature of the condensate is usually around 40 ° C., but at the installation position of the conductivity meter 4 it has dropped to 20-30 ° C. The heating means 15 heats the water to be treated to about 50 ° C. This improves the current efficiency of the decationization apparatus 3. This change in the molar conductivity ^{H +} ions and OH ^- Na ⁺ ions and Cl than ion ^- larger towards the ion because the high temperature as Na ⁺ ions easy to move. However, in order to prevent deterioration of the cation exchange membranes 34 and 35 of the decationizing device 3 and the cation exchanger 39, it is not preferable to supply treated water exceeding 50 ° C. to the decationizing device 3. Therefore, it is desirable that the water to be treated be heated in the range of 40 to 50 ° C. Since the heating means 15 is for improving the current efficiency of the decationization device 3, the decationization device 3 of the present embodiment is limited to EDI or ED.

  The third embodiment can be combined with the first and second embodiments. For example, in the first embodiment, the heating means 15 of the third embodiment can be provided between the junction of the pipe 6 with the dilution water supply line 11 and the inlet of the decationizing apparatus 3. In the second embodiment, the heating means 15 of the third embodiment can be provided between the valve 7 of the pipe 6 and the inlet of the decationizing apparatus 3.

(Example)
The simulated water simulating seawater was supplied to the conductivity measuring system of decationized ionic water of the first to third embodiments, and the seawater leakage detection capability at the time of steady operation of the power plant was confirmed. An EDI was used as the decationizing device 3, and a mesh plate made of SUS 304 was used as the negative electrode 37, and a meshed plate made of titanium was coated with platinum as the positive electrode 36. For the cation exchange membranes 34, 35, a strongly acidic cation exchange membrane (NEOCEPTA CMX (manufactured by Tokuyama Soda Co., Ltd.)) in which a sulfonic acid group is introduced into a styrene-divinylbenzene copolymer matrix was used. The demineralization chamber 31 was filled with monolith. The ion exchange capacity of the monolith was 4.0 mg equivalent / g in terms of dry porous material, and mapping of sulfur atoms using EPMA confirmed that the sulfonic acid group was uniformly introduced into the porous material. . Further, as a result of SEM observation, the internal structure of this porous body has an open cell structure, most of macropores having an average diameter of 30 μm overlap, and the average diameter of mesopores formed by the overlap of macropores and macropores The value was 5 μm and the total pore volume was 10.1 ml / g. As conductivity meter 4, 875 CR (monitor) and 871 CC (sensor) manufactured by Foxboro Corp. were used.

  As simulated water (water to be treated), ammonia water in which ammonia was dissolved in pure water with a specific resistance of 18.2 MΩ · cm (conductivity: 0.054 μS / cm) was used. Sodium chloride was further added to the ammonia water to simulate seawater leakage. The flow rate of the water to be treated was 50 l / h, the direct current applied between the positive electrode 36 and the negative electrode 37 was 1.0 A, and the voltage was 40 V.

  (Comparative example) In simulated water with an ammonia concentration of 2.0 mg / L (pH 10.0), the conductivity of the outlet water of the decationization device 3 is 0.06 μs / cm, and the ammonia concentration is 3.6 mg / L (pH 10) In the simulated water of .3), the conductivity of the outlet water of the decationization apparatus 3 was 0.095 μS / cm and ammonia 5 μg / L. From this, it was found that some ammonia could not be removed.

  (Example 1: Corresponds to the first embodiment) Ammonia water is added to pure water to prepare ammonia water of pH 10.3, and 0.5 mg / L NaCl (Example 1-1) and 1 mg are added thereto. / L (Example 1-2) The simulated water added was created. The simulated water of pH 10.3 and the pure water are mixed at a volume ratio of 1: 4 to prepare simulated water of pH 9.7 (5 times diluted water), and the decationization treatment is carried out by the decationization device 3 and the treatment The conductivity of the water was measured.

  The electrical conductivity of Example 1-1 (NaCl concentration after dilution: 0.1 mg / L) is 1.2 μS / cm, and the conductivity of Example 1-2 (NaCl concentration after dilution: 0.2 mg / L) is 1. It was 4 μS / cm. This corresponds to the theoretical value of the electrical conductivity when Cl becomes hydrochloric acid. It turned out that a seawater leak can be detected from this.

  Example 2 (corresponding to the second embodiment) The pH of the ammonia water was changed from 10.0 (ammonia concentration 2.0 mg / L) to 10.3 (ammonia concentration 3.6 mg / L) of the comparative example. The simulated water which added 0.5 mg / L (Example 2-1) and 1 mg / L (Example 2-2) of NaCl to this ammonia water was created. The flow rate of the simulated water supplied to the decationizing apparatus 3 and the conductivity meter 4 was reduced to half of the comparative example. In Example 2-1 (NaCl concentration 0.5 mg / L), the conductivity was 3.6 μS / cm, and in Example 2-2 (NaCl concentration 1 mg / L), the conductivity was 7.2 μS / cm. . This corresponds to the theoretical value of the electrical conductivity when Cl becomes hydrochloric acid. It turned out that a seawater leak can be detected from this.

  (Example 3: Correspond to the third embodiment) The pH of the ammonia water was changed from 10.0 (ammonia concentration 2.0 mg / L) of the comparative example to 10.3 (ammonia concentration 3.6 mg / L). The simulated water which added 0.5 mg / L (Example 3-1) and 1 mg / L (Example 3-2) of NaCl to this ammonia water was created. The simulated water was heated to 50 ° C. and supplied to the decationizing apparatus 3. In Example 3-1 (NaCl concentration 0.5 mg / L), the conductivity was 3.6 μS / cm, and in Example 2-3 (NaCl concentration 1 mg / L), the conductivity was 7.2 μS / cm. . This corresponds to the theoretical value of the electrical conductivity when Cl becomes hydrochloric acid. It turned out that a seawater leak can be detected from this.

1,101,201 conductivity measurement system 2 flow meter 3 deionization apparatus 4 conductivity meter 6 piping 7 valve 8 condensate piping 10 dilution device 15 heating means 31 demineralization room 32, 33 concentration room 38 power supply 39 cation exchange body

Claims (11)

Adding diluted water to treated water containing cations and anions to produce diluted treated water having a lowered pH;
Supplying the diluted treated water to a decationization apparatus to produce decationized water;
Supplying the decationized water generated by the decationization apparatus to a conductivity meter to measure the conductivity of the decationized water.   The method of measuring the conductivity of decationized water according to claim 1, wherein the pH of the water to be treated is 10 or more.   The method for measuring the conductivity of decationized water according to claim 1 or 2, wherein the dilution water is decationized water previously generated by the decationization apparatus. Passing treated water containing positive ions and negative ions through a flow path resistance member whose pressure resistance is greater on the upstream side and on the downstream side;
Supplying the treated water passed through the flow path resistance member to a decationizing apparatus to generate decationizing water;
Supplying the decationized water generated by the decationization apparatus to a conductivity meter to measure the conductivity of the decationized water. Heating water to be treated containing positive and negative ions;
Supplying the heated treated water to a decationization apparatus to generate decationized water;
Supplying the decationized water generated by the decationization apparatus to a conductivity meter to measure the conductivity of the decationized water.   The method for measuring the conductivity of decationized ion water according to any one of claims 1 to 5, wherein the water to be treated is a condensate of a thermal power plant or a nuclear power plant. A dilution device that adds diluted water to treated water containing cations and anions to generate diluted treated water whose pH is lowered;
A decationizing apparatus for generating decationized water from the diluted treated water;
And a conductivity meter for measuring the conductivity of the decationized water produced by the decationization device.   The dilution device includes a container for storing decationized water generated by the decationization device and passed through the conductivity meter, a water supply line connecting the container to the inlet of the decationization device, and the water The system for measuring the conductivity of decationized water according to claim 7, further comprising: a transfer pump provided on the supply line. A treated water containing positive ions and negative ions is passed through, and the pressure resistance is larger in its upstream and downstream flow path resistance members,
A decationizing apparatus for generating decationized water from the treated water passed through the flow path resistance member;
And a conductivity meter for measuring the conductivity of the decationized water produced by the decationization device. Heating means for heating the water to be treated containing positive and negative ions;
A decationizing apparatus for generating decationized water from the treated water heated by the heating unit;
And a conductivity meter for measuring the conductivity of the decationized water produced by the decationization device.   The system for measuring the conductivity of decationized ion water according to any one of claims 7 to 10, wherein the water to be treated is a condensate of a thermal power plant.

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