JP2009268999A - Method and apparatus for treating water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce heat loss owing to a cooling operation of blowdown water and to suppress consumption of chemicals such as ammonia by reducing load on the desalination of impurity ions by using a desalination unit for selectively removing only impurity ions at high temperature. <P>SOLUTION: In a method for treating ammonia-containing water 12 to be treated by using the desalination unit 11 having a pair of diaphragms 14 and electrodes 17 which are arranged to be opposed to each other on the outside of the pair of diaphragms 14 and between which a DC voltage is applied, the water 12 to be treated is treated at ≥100°C to obtain the treated water from which impurity ion components are removed and in which ammonia is concentrated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a water treatment technique in a nuclear power plant or thermal power plant that contains ammonia in cooling water, and in particular, a water treatment method and a water treatment device in secondary water of a pressurized water nuclear power plant or system water of a thermal power plant. About.

  In general, in a pressurized water power plant, a steam generator is divided into a pressurized water reactor primary system and its secondary system, and the steam generator generates heat from the high-temperature high-pressure water generated in the reactor of the primary reactor. However, steam is generated in the secondary reactor system. In the pressurized water reactor secondary system, steam generated by a steam generator is sent to a steam turbine, and this steam turbine is driven by the turbine to generate electricity.

  The steam expanded by driving the steam turbine is subsequently introduced into the condenser, where it is cooled and condensed in the condenser to become condensed water. This condensate is subjected to demineralization treatment for removing ions by an ion exchange resin or the like in a condensate demineralizer as necessary, and then heated by a heater of a power plant system and supplied to a steam generator.

  Water supplied to the steam generator is injected with a chemical injection material from the viewpoint of suppressing corrosion of structural materials (piping and equipment) in the reactor secondary system of the power plant system. Among these, ammonia or an amine compound is used as a pH adjuster, and hydrazine is used as an oxygen scavenger.

  On the other hand, in the steam generator, impurities such as ions and corrosion products brought into the reactor secondary system, which is the power plant system, are concentrated, so corrosion of the heat transfer tubes in the steam generator and reduced heat transfer It is a factor to cause. For this reason, operation which discharges a part of water in a steam generator (blowdown) is performed.

  Blowdown water from the steam generator is guided and purified by existing water purification equipment such as a condensate demineralizer or a blowdown water treatment device provided in the blowdown water discharge path. After the pH adjusting agent, which is a drug injection substance contained in the blowdown water, is removed by the desalting process of the condensate demineralizer, a new drug injection substance is separately injected. However, removing the pH adjusting agent with the condensate demineralizer and injecting a new drug separately increases the ion removal load in the condensate demineralizer and increases the drug injection cost.

  Therefore, as a method to suppress the removal of the pH adjuster from the blow-down water of the steam generator and reduce the cost of the injected medicine, the blow-down water is removed from the condensate demineralizer (condensate demineralizer) as necessary. Means for bypassing has been proposed (Patent Documents 1 to 3).

On the other hand, when the blowdown water is processed by the condensate demineralizer or the blowdown water treatment device provided in the blowdown water discharge path, the blowdown water from the steam generator is at a high temperature. In a salt container or blowdown water treatment apparatus, since ion effect resin weak against heat is used, blowdown water is cooled and treated at room temperature. In this way, the existing water purification equipment cools the blow-down water before treatment, and the condensate demineralizer cannot sufficiently maintain the desalting function without using this cooling operation technique. (Patent Documents 1 and 4).
JP 2000-171585 A JP 2000-258589 A JP 2005-329314 A JP 2006-226697 A JP 11-47560 A JP 2007-90299 A JP 2006-43580 A, JP 2006-88004 A, JP 2006-136846 A Y.Asakura et al. “In-Line Monitor for Electrical Conductivity of High-Temperature, Aqueous Environments” J. Electrochem. Soc., Vol. 136, No. 11, pages 3309-3313 (1989)) Yoshihiro Takebayashi, “Spectroscopic measurement of acid-base equilibrium in supercritical water / methanol” Science and Technology of High Pressure Vol.16, No.2, pp. 105-112 (2006)

  In conventional water treatment technology in which a blowdown water treatment device such as an electric desalination device is provided in the secondary blowdown water discharge path of a pressurized water nuclear power plant, pH adjustment is performed in addition to impurity ions in the blowdown water. Since the ammonia that is the agent is also removed at the same time, it is possible to reduce the load on the condensate demineralizer, while it is difficult to reduce the cost of the ammonia to be injected.

  For this reason, a technique for reusing the ammonia removed by the desalting apparatus has been proposed (Patent Document 5). In this recycling technique, it is necessary to separate and purify the impurity ions concentrated together with the removed ammonia. The device may be complicated and increase the cost.

  In addition, a technology has been proposed in which only anionic impurities are removed at high temperatures by using an electric regeneration-type desalting apparatus using a heat-resistant anionic material, and a cationic substance that is a drug injection substance is permeated and recycled (patent document). 6) In this method, the impurity cation may be reinjected together with the drug cation.

  On the other hand, blowdown water discharged from a steam generator at a high temperature is vulnerable to high temperatures in the existing desalination technology using an ion exchange resin and the conventional electric regenerative deionization apparatus using an ion exchange resin and an ion exchange membrane. From the viewpoint of the heat resistance of the ion exchange resin, it is required to be cooled to room temperature in order to maintain the ion exchange function, and additional equipment such as a cooling facility using a heat exchanger is required, resulting in poor thermal efficiency. There was also a problem with cost.

  Moreover, although there exists a desalting apparatus that can operate under high temperature and high pressure (Patent Documents 7 to 9), it has not been configured to selectively remove only impurity ions from blowdown water.

  For this reason, if only the impurity ions can be selectively removed from the high-temperature blowdown water, and a desalting technique for leaving ammonia to be injected and adjusted at a higher concentration than the impurity ions can be established, The ion removal load can be reduced, and the cost of injecting the ammonia drug can be reduced, which is advantageous.

  The present invention was made in consideration of the above-described circumstances, and in a water treatment method and a water treatment apparatus for a pressurized water reactor secondary system and a power generation system system of a thermal power plant that require chemical injection into the system water, By using a desalination treatment device that can selectively remove only impurity ions at high temperatures, the load for impurity ion desalting and purification can be reduced, heat loss associated with cooling operation of blowdown water can be reduced, It aims at providing the water treatment technique which can suppress chemical | medical agent consumption.

  In order to solve the above-described problems, the water treatment method according to the present invention removes water to be treated containing ammonia by applying a DC voltage to a pair of diaphragms and electrodes disposed opposite to the outside of the pair of diaphragms. In the water treatment method of treating with a salt device, the treated water is treated at 100 ° C. or higher to obtain treated water enriched with ammonia from which impurity ion components have been removed.

  The water treatment apparatus according to the present invention applies a direct-current voltage to water to be treated comprising steam-generator blowdown water containing ammonia to a pair of diaphragms and electrodes disposed opposite to the outside of the pair of diaphragms. In a water treatment apparatus that is treated by a desalting apparatus and reused as a water supply source of a steam generator, the treated water is treated at 100 ° C. or higher, thereby condensing ammonia from which impurity ion components have been removed. It is characterized by obtaining.

  According to the water treatment method and the water treatment apparatus according to the present invention, by using a desalination treatment apparatus that can selectively remove only impurity ions at a high temperature, the load for impurity ion desalting and purification is reduced, and blowdown water is reduced. It is possible to provide a water treatment technique capable of reducing heat loss associated with the cooling operation and suppressing consumption of chemicals such as ammonia.

Embodiments of a water treatment method and a water treatment apparatus according to the present invention will be described with reference to the accompanying drawings.
[First Embodiment]
1st Embodiment of this invention is related with the electrical desalination apparatus 11 used for the water treatment apparatus which concerns on this invention.
As shown in FIG. 1, the electrical desalting apparatus 11 has an introduction path for the treated water 12 and a discharge path for the impurity desalted treated water 13. A diaphragm 14 arranged, an electrode 17 for direct current application arranged on the outside of the diaphragm, a desalting part 15 formed between the diaphragms, and a concentration part 16 formed between each diaphragm and each electrode. The to-be-treated water 12 that is configured and concentrated with ammonia is introduced into the desalting unit 15 and discharged as desalted processing water 13, and the concentrated water of removed impurities is discharged from the concentrating unit 16 as impurity concentrated drainage 19.

  As shown in FIG. 1, the electrical desalting apparatus 11 performs a desalting process by applying a direct current to the electrode 17. At that time, the case and the electrode 17 of the electrodeionization device 11, the case and the diaphragm 14 of the electrodeionization device 11, the electrode 17 and the membrane 14, and the paired membranes 14 are electrically insulated from each other. Is desirable.

  Further, it is desirable that the liquid filled in the desalting unit 15 and the concentration unit 16 in the electric desalting apparatus 11 does not mix with liquid from a place other than the diaphragm 16 inside the electric desalting apparatus 11. The electrode 17 is made of a material that does not easily elute the constituent components of the electrode 17 into the impurity demineralized water 13 during desalting, and a material that can be used stably in the operating temperature and current stable range of the electric desalting apparatus 11 is selected. .

  The diaphragms 14 that partition the desalting unit 15 and the concentration unit 16 in the electric desalting apparatus 11 are arranged to face each other in pairs, and are arranged in parallel to the electrodes 17 at equal intervals. The diaphragm 14 is made of a material such as a metal, an alloy, ceramics, or a heat-resistant resin, and even if the component is high-temperature treated water that is steam generator blowdown water, the desalination treatment operation environment The materials that are difficult to elute and corrode are selected and used. For the diaphragm 14, for example, a parallel arrangement of a flat plate (plate) shape or a parallel arrangement configuration of a concentric cylindrical shape (elliptical tube shape, rectangular tube shape) is adopted.

  In the electrical desalting apparatus 11, the liquid 12 to be treated is introduced into the desalting unit 15, and the ionic component contained in the introduced water 12 to be treated is a potential gradient applied by the electrode 17 inside the electrical desalting apparatus 11. As a result, the membrane 14 passes through the diaphragm 14 in contact with the desalting unit 15 and moves out of the desalting unit 15 by electrophoresis. As a result, treated water from which ions have been removed by the electrical desalting apparatus 11 is discharged from the desalting unit 15 as the impurity desalted treated water 13.

  The ionic component moved to the concentration chamber 16 disposed outside the desalting unit 15 and the diaphragm 14 due to the potential gradient in the desalting unit 15 in the electric desalination unit 11 is transferred to the outside of the electric desalination unit 11 as the impurity concentration drainage 19. Discharged.

Here, the removal performance test results of ammonia and impurity ions using the electric desalting apparatus 11 shown in FIG. 1 are shown below.
[Evaluation test conditions]
Electrodesalting cell Electrode area 79cm ²
Desalination part volume 47cm ³
Desalination width 0.6cm
Untreated water supply 6600g / h
Applied voltage 60V
Impurity-concentrated wastewater Trace amount (almost 0 g / h)
Processing time 60 minutes

[Evaluation test results]
FIG. 2 shows the result of adding 20-30 μg / L of sodium ions and sulfate ions to ammonia water adjusted to pH 9 and pH 10 at 25 ° C., followed by desalting.
As shown in FIG. 2, in the environment of pH 9 and pH 10, the ammonia removal rate was 10% or less at a high temperature of 100 ° C. or higher. That is, a treated water in which 90% or more of ammonia remained in the treated water could be obtained.

FIG. 3 shows the removal selection ratio of the sodium ion and sulfate ion removal rate to the ammonia removal rate, that is, the ammonia removal efficiency ratio in the evaluation test results.
Compared with normal temperature, the sodium ion and sulfate ion removal selectivity with respect to ammonia increased at a high temperature of 100 ° C. or higher.

  From the above evaluation test results, at 100 ° C. or higher and pH 9 or higher, the ammonia recovery rate was 90% or higher, and the impurity ion removal selectivity to ammonia removal was 10 or higher. Therefore, the selective removal ratio of ammonia and impurity ions is 4 times or more at 100 degrees or more and further at pH 9 or more.

The ionization equilibrium of ammonia in this removal performance evaluation test is expressed by Equation 1.
NH ₃ + H ₂ O═NH ₄ ⁺ + OH ⁻ (Formula 1)
In Equation 1, as the temperature increases, the density of water (H ₂ O) decreases, the ammonium ion ratio decreases (Non-Patent Document 2), and the pH increases, the ammonium ion ratio decreases as well as the high temperature effect. Since most of the water to be treated exists as ammonia, the proportion of ammonium ions that are electrically removed is reduced, and as a result, ammonia removal can be suppressed.

The ion ratio in the ionization equilibrium of ammonia represented by Formula 1 is shown in FIG.
From FIG. 4, it can be seen that the higher the temperature and the higher the concentration, the lower the ammonium ion ratio, and the tendency of the ammonia removal rate decreasing at pH 9 shown in FIG.

  In particular, when the ammonia concentration is 1 mg / L or more, the ionization ratio of ammonia becomes 50% or less, and this ionization is further suppressed by increasing the temperature, so that the ammonia removal suppressing effect in the present invention is enhanced.

  On the other hand, although it is known that the ionic conductivity in high temperature water will increase, so that it becomes high temperature (nonpatent literature 1), this is because the ion movement in an electric field accelerates by high temperature. This is due to the synergistic effect of decreasing the ionization rate of ammonia and promoting the movement of impurity ions, and the selective separation of ammonia and impurity ions is enhanced at high temperatures.

  According to the water treatment apparatus shown in the first embodiment, by appropriately selecting the operating environment such as temperature, pH, and ammonia concentration, the amount of ammonia in the drug injection substance that exists at a high concentration relative to the impurity ions can be increased. Impurity ions can be removed from the treated water 12 while retaining the portion.

[Second Embodiment]
A second embodiment of the water treatment apparatus according to the present invention will be described with reference to FIG.
In the description of the water treatment apparatus of this embodiment, the same components and operations as those of the water treatment apparatus according to the first embodiment shown in FIGS. Turn into.
FIG. 5 is a diagram showing the removal characteristic of the sulfate ion component in the first embodiment. In addition, pH shown in FIG. 5 is a hydrogen ion concentration under 25 degreeC.

As shown in FIG. 2 and FIG. 3, it is possible to remove ions retaining ammonia by desalting at 100 ° C. or higher. However, the sulfate ion component shown in FIG. The rate tends to decrease. This is because the ionization of the sulfuric acid component represented by Formula 2 and Formula 3 tends to be suppressed at high temperatures (Non-Patent Document 1), and the ionization of sulfuric acid represented by Formula 2 and Formula 3 is a hydrogen ion (H ⁺ ) Due to concentration, ie pH dependence.
H ₂ SO ₄ = H ⁺ + HSO ₄ ⁻ (Formula 2)
HSO ₄ ⁻ = H ⁺ + SO ₄ ²⁻ (Formula 3)
For this reason, for example, it is desirable to operate the temperature range during the desalting treatment in a range of 100 ° C. or more and 200 ° C. or less at pH 9 and 100 ° C. or more and 250 ° C. or less at pH 10 or less.

In the case of FIG. 5, for example, as an upper limit temperature at which sulfate ion removal is 50% or more, the pH value of the water to be treated is applied to Formulas 5 to 7, which are general thermodynamic temperature dependence formulas, and is obtained by Formula 4. Apply the solution on the higher temperature side of the measured temperature T (K). However, this is obtained according to the desalting conditions of the electric desalting apparatus 11 in this embodiment.
A / T ² + B / T + C = 0; T: temperature (K) (formula 4)
A = 91416314 × pH−1117340318 (Formula 5)
B = −514858 × pH + 6080973 (Formula 6)
C = 698.38 × pH−8021.1 (Formula 7)

  Thus, according to the second embodiment, by setting the treatment upper limit temperature according to the treated water pH, the operating environment such as temperature, pH, ammonia concentration, etc. is appropriately selected, and the impurity ions are selected. Impurity ions can be removed from the water to be treated 12 while retaining most of the ammonia in the drug injection substance present at a high concentration.

[Third Embodiment]
A water treatment apparatus according to a third embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a configuration diagram of a water treatment device according to the third embodiment of the present invention.
In describing the water treatment apparatus of this embodiment, the same components and operations as those of the water treatment method and apparatus shown in FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description is omitted or simplified.

  The water treatment apparatus according to the third embodiment is applied to a pressurized water nuclear power plant, and a steam generator 1 is provided in a power generation system system, and the system is connected to the pressurized water reactor primary by the steam generator 1. Divided into systems and secondary systems.

  High-temperature and high-pressure water generated in a nuclear reactor (not shown) is sent to the steam generator 1 where it is heat-exchanged with water supplied to the steam generator 1. The steam generated in the steam generator 1 is supplied to the low-pressure turbine 4 via the high-pressure turbine 2 and the moisture separator 3, and the high-pressure turbine 2 and the low-pressure turbine 4 are driven to generate power.

  A part of the steam supplied to the high-pressure turbine 2 is used as a heat source for the high-pressure feed water heater 9 as high-pressure extraction air 2-1, and then supplied to the water supply system of the steam generator 1. The water removed from the steam is supplied to the water supply system of the steam generator 1. The low-pressure extraction 4-1 extracted from the low-pressure turbine 4 is supplied to the water supply system of the steam generator 1 after being used as a heat source for the low-pressure feed water heater 7, and the main steam discharged from the low-pressure turbine 4 is It becomes water in the condenser 5 and is introduced into the water supply system of the steam generator 1 through the condensate pump 5-1.

  In the water supply system, the water quality is purified by the condensate demineralizer 6 from the condensate pump 5-1, the water quality is adjusted by injecting the chemical 20, the temperature is adjusted by the low-pressure feed water heater 7, and the deaerator 8 is used. After the gas-liquid separation and the temperature adjustment in the high-pressure feed water heater 9, water is supplied to the steam generator 1.

  Further, the steam generator 1 has a steam generator blowdown water discharge path for discharging a part of the water of the steam generator 1 in order to prevent corrosion of the heat transfer pipe in the steam generator 1 and deterioration of heat transfer performance. 10 is arranged. This blowdown water discharge path 10 extends to the condenser 5 side and is connected to the downstream side of the condenser 5 and the upstream side of the condensate demineralizer 6. In the middle of the blow-down water discharge path 10, the electric desalination apparatus 11 described in the first embodiment is provided.

  In addition, the electric desalination apparatus 11 is provided with a bypass path 10-1 through which blowdown water of the steam generator 1 is bypassed. The blowdown water discharged from the steam generator 1 is introduced into the electric desalination apparatus 11 as the treated water 12 through the steam generator blowdown water discharge path 10, and the desalted water 13 is supplied to the steam generator 1. Sent to the water supply system.

  On the path of the steam generator blowdown water discharge path 10, components such as a flash tank and a heat exchanger may be arranged as necessary (not shown). This technique may be used. However, it is desirable that the configuration and operation be such that fluctuations in the amount and temperature of blowdown water sent to the electric desalting apparatus 11 are reduced.

  By the way, since the electric desalination apparatus 11 provided in the steam generator blowdown water discharge path 10 can perform the impurity ion desalination operation at a high temperature, the steam generator blow required for the conventional water treatment apparatus is required. The cooling operation at the time of the down water treatment becomes unnecessary, and the amount of the cooling operation up to normal temperature can be reduced. The form of the desalting apparatus operated under high temperature and high pressure is not limited to that shown in FIG. 2, and various desalting apparatuses such as those disclosed in Patent Documents 7 to 9 are employed. Can do.

  In the electrical desalting apparatus 11, impurities in the steam generator blowdown water are removed by the desalting unit 15 in the electrical desalting apparatus 11, and the impurity desalinized treated water 13 that retains much of the ammonia as a pH adjuster is covered. It is discharged while retaining the heat quantity of the treated water 12.

  The impurity demineralized treated water 13 is returned to, for example, the downstream side of the deaerator 8 of the water supply system and is returned to the steam generator 1. The treated water 13 that has been refluxed is heat-exchanged with the high-temperature high-pressure water from the nuclear reactor in the steam generator 1 to be vaporized and supplied to the high-pressure turbine 2 and the low-pressure turbine 4.

  At that time, the supply location of the impurity demineralized water 13 treated by the electric desalting apparatus 11 may be selected according to the temperature of the water to be treated supplied to the electric desalting apparatus 11. In particular, when 13 is treated water that has been desalted at a high temperature, it is desirable to select a location that can be operated at a high temperature. The supply of the impurity desalted treated water 13 to the water supply system is connected by arbitrarily installing equipment such as a pump in consideration of the temperature and pressure of the supply destination.

  Moreover, when the drain system which supplies the drain water of the high voltage | pressure feed water heater 9 which uses the turbine extraction (high pressure steam) from the high pressure turbine 2 as a heat source to the PWR secondary system is arrange | positioned, impurity desalination treated water is supplied to this drain system. 13 may be supplied.

  Furthermore, the electric desalination apparatus 11 can arrange a plurality of apparatuses of the same form and can carry out continuous purification of blow-down water of the steam generator 1. At that time, water purification and the electric desalination apparatus 11 can be performed. The cleaning operation may be switched. In this way, by disposing a plurality of the electrical desalting apparatuses 11, it is possible to always stably purify the PWR secondary system water.

  According to the third embodiment, the desalting operation of the electric desalting apparatus 11 at a high temperature maintains the heat amount of the steam generator blowdown water and does not reduce the ammonia amount. Recycling of heat and ammonia supplied to the generator 1 and purification of impurity ions are possible, and the cost can be reduced by reducing the amount of chemicals.

  Since ammonia and impurity ions can be selectively separated at a high temperature in this manner, the impurity-treated water 13 is returned to the water supply source of the water to be treated 12 in a state where ammonia remains, thereby purifying the impurities and ammonia. Can be recycled. Furthermore, heat treatment in the steam generator water supply system can be greatly improved by processing at a high temperature.

[Fourth Embodiment]
A water treatment apparatus according to a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a configuration diagram of a water treatment device according to the fourth embodiment of the present invention.
In the description of the water treatment apparatus of this embodiment, the same components and functions as those of the water treatment apparatus shown in FIGS. 1 to 6 are denoted by the same reference numerals, and redundant description is omitted or simplified.

  The water treatment apparatus shown in the fourth embodiment is applied to the secondary system of the pressurized water nuclear power plant as in the third embodiment, but the point different from the third embodiment is the secondary system. Impurities-concentrated waste water 18 discharged from the electric desalination apparatus 11 provided in the steam generator blowdown water discharge path 10 is supplied to the condensate demineralizer 6 which is an existing condensate purification facility.

  A heat recovery device 30 such as a heat exchange device is disposed on the supply path 18-1 as necessary. The heat recovery device 30 may be an existing one, and its form and the like are not particularly limited, but the heat recovered by the heat recovery device 30 is reused in the secondary system of the pressurized water nuclear power plant. It is preferable.

  Here, the condensate demineralizer 6 has a configuration in which a plurality of condensate demineralizers 6 are arranged in parallel and the supply path can be switched for maintenance of the ion exchange resin filled in the condensate demineralizer 6. Yes.

  The impurity-concentrated waste water 18 that concentrates the impurity ions discharged from the electric desalting apparatus 11 is supplied to a desalinator other than the condensate demineralizer during the purification operation among a plurality of condensate demineralizers 6 arranged. Purify impurity ions introduced and concentrated.

  Differentiating the condensate and the impurity-concentrated waste water 18 and purifying them with the condensate demineralizer 6 means that the condensate demineralization is performed by distinguishing the quantity and quality of the water to be treated that is purified by the condensate demineralizer 6 This is effective for maintaining the performance of the ion exchange resin filled in the vessel 6 and the quality of the raw water discharged from the condensate demineralizer 6 and supplied to the steam generator 1. Moreover, the amount of supplementary water in the secondary system water of the pressurized water nuclear power plant can be reduced by purifying impurities in the impurity-concentrated waste water 18 discharged from the electric desalination apparatus 11 and reusing the water. it can.

  According to the water treatment apparatus according to the fourth embodiment, by supplying the concentrated impurity waste water 18 to the dewatering desalinator 6, electric desalination is performed when purifying impurity ions contained in the blow-down water of the steam generator 1. It is possible to maintain the water quality of the water supply system while stably purifying the concentrated impurity waste water 18 discharged from the apparatus 11. As a result, impurities can be removed while retaining and recycling most of the ammonia present at a high concentration relative to the impurity ions.

  Furthermore, even in the desalting treatment at high temperature, it is possible to realize water treatment with less impurity ion desalting and purification load, ammonia consumption, and less heat loss, and the nuclear power plant can be efficiently and appropriately operated.

The schematic diagram of the desalination apparatus which concerns on the 1st Embodiment of this invention. The figure which shows the temperature dependence of the ammonia removal rate which concerns on the 1st Embodiment of this invention. The figure which shows the temperature dependence of the selection ratio of impurity ion removal with respect to ammonia removal which concerns on the 1st Embodiment of this invention. The figure which shows the temperature dependence of the ammonia ionization ratio which concerns on the 1st Embodiment of this invention. The figure which shows the temperature dependence of the sulfate ion removal rate which concerns on the 2nd Embodiment of this invention. The block diagram of the water treatment apparatus which concerns on the 3rd Embodiment of this invention. The block diagram of the water treatment apparatus which concerns on the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steam generator, 2 ... High pressure turbine (steam turbine), 2-1 ... High pressure extraction, 3 ... Moisture separator, 4 ... Low pressure turbine (steam turbine), 4-1 ... Low pressure extraction, 5 ... Condenser 5-1 ... Condensate pump, 6 ... Condensate demineralizer, 7 ... Low pressure feed water heater (low pressure heater), 8 ... Deaerator, 9 ... High pressure feed water heater (high pressure heater), 10 ... Steam generator Blowdown water discharge path, 10-1 ... Steam generator blowdown water bypass path, 11 ... Desalination device, 12 ... Water to be treated, 13 ... Impurity desalted water, 14 ... Separator, 15 ... Desalination section, 16 DESCRIPTION OF SYMBOLS ... Concentration part, 17 ... Electrode, 18 ... Impurity concentration drainage, 18-1 ... Supply path, 20 ... Drug, 30 ... Heat recovery apparatus.

Claims (8)

  In a water treatment method for treating water to be treated containing ammonia by a desalting apparatus that applies a DC voltage to a pair of diaphragms and electrodes disposed opposite to the outside of the pair of diaphragms, the water to be treated is 100 ° C. or higher. The water treatment method characterized by obtaining the treated water in which the ammonia from which the impurity ion component was removed was concentrated by processing by this.   The water treatment method according to claim 1, wherein the water to be treated has a pH of 9 or more.   The water treatment method according to claim 1, wherein the ammonia concentration in the water to be treated is 1 mg / L or more.   The water treatment method according to any one of claims 1 to 3, wherein a treatment temperature of the water to be treated is determined by a pH of the water to be treated.   The water treatment method according to any one of claims 1 to 4, wherein the water to be treated is blowdown water of a steam generator of a power generation system.   The water treatment method according to claim 5, wherein the power generation system is a pressurized water nuclear power plant.   The water treatment method according to claim 5 or 6, wherein the treated water discharged from the desalination apparatus is returned to a water supply system of the steam generator.   Water to be treated comprising steam generator blowdown water containing ammonia is treated by a desalting apparatus that applies a DC voltage to a pair of diaphragms and electrodes disposed opposite to the outside of the pair of diaphragms, In the water treatment apparatus to be reused as a water supply source, the water to be treated is obtained by treating the water to be treated at 100 ° C. or higher to obtain the treated water in which the ammonia from which the impurity ion component has been removed is concentrated.

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