JP3226971B2 - Water sampling and regeneration cycle controller for ion exchange equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to water sampling of an ion exchange apparatus.
More specifically, regarding the regeneration cycle control device, more specifically, the use of an ion exchange device capable of maximizing the capacity of the ion exchange resin used and estimating the available water amount of the ion exchange device in real time. It relates to a water-regeneration cycle control device.

[0002]

2. Description of the Related Art An ion exchange apparatus is used for producing pure water or ultrapure water and for condensing water in a pressurized water reactor. For example, for condensate desalination of a pressurized water reactor, as shown in FIG. 2, a mixed bed type ion exchange apparatus 1 in which a cation exchange resin and an anion exchange resin are mixed and stored at a predetermined ratio.
Is used. A condensate pump 2 and a condenser 3 are arranged on the upstream side of the ion exchange device 1, and a condensate booster pump 4 is arranged on the downstream side. Condensed water to be treated and formed is passed through the ion exchange device 1 as shown by the arrow in the figure, where cations and anions in the condensed water are removed and purified, and the treated water is again used for generating steam. You.

[0003] In this water passage, in order to adjust the pH of condensed water circulating in the path and to deoxygenate the water, a humanrazine injector 5 and an ammonia injector are usually provided in the middle of the ion exchange device 1 and the condensate booster pump 4. And a predetermined concentration of human azine (N ₂ H ₄ ) in the treated water purified from these injectors through
And ammonia (NH ₃ ) are injected. N ₂ injected
H ₄ is N ₂ H ₅ ⁺ ion, and the implanted NH ₃ is NH _3
4 ⁺ While in the form of ions are consumed by flowing water flow paths present in the passing water, residual amount of unconsumed come to reflux the ion exchange apparatus 1 again.

Incidentally, the above-mentioned ion exchange apparatus 1 is usually constituted by arranging a plurality of units in parallel, and before the ion exchange resin of a certain ion exchange apparatus reaches saturation and loses its processing ability,
The water exchange operation is switched to another ion exchange device, or the ion exchange resin that has reached saturation by replacing the resin that has undergone the regeneration treatment is subjected to the regeneration treatment. In this regeneration treatment, generally, the ion exchange resin in the ion exchange device is backwashed and separated using the specific gravity difference between the cation exchange resin and the anion exchange resin, and then, for example, the anion exchange resin is transferred to a separate regeneration tower. A method of passing an aqueous solution of HCl through the cation exchange resin and passing an aqueous solution of NaOH through the anion exchange resin is applied.

[0005] However, at present, it is practically impossible to completely backwash and separate the cation exchange resin and the anion exchange resin. I will. Therefore, when an aqueous HCl solution is passed through the cation exchange resin, the remaining anion exchange resin is reversely regenerated, Cl ^- is eluted from the reversely regenerated resin, and about 90% of the regeneration is mainly performed from an economic viewpoint. to have implemented playback rate, Cl ^- in the cooling water of a pressurized water reactor must be kept in the order of ppt concentration, Cl exceeding the allowable value ^- may be leaking, very inconvenient It is.

Therefore, conventionally, after condensed water is condensed by extracting a predetermined amount (for example, 200,000 tons) of water for a predetermined number of days, the ion exchange capacity of the ion exchange resin used has not been lost. However, the reproduction process is performed unconditionally early. Then, when such a water-collection / regeneration cycle is repeated a predetermined number of times, it is determined that the ion exchange resin has deteriorated and its life has expired, and is replaced with a new ion exchange resin.

A typical embodiment of the water cycle per unit of the ion exchange apparatus is about 12 days, and the ion exchange resin is regenerated once every two days. An operation plan has been compiled. However, for example, when the output of the entire power plant is adjusted, when the seawater for cooling of the condenser leaks and enters the water passage, or when the regeneration processing system of the ion-exchange resin falls out of order, the above-described routine is performed. It is necessary to change the operation plan table in order to respond to each situation.

When the schedule is changed, the exchange capacity of the ion exchange resin, the ion concentration in the condensed water at the inlet of the ion exchange apparatus, the ion concentration at the outlet side, the existing ratio of each ion exchange resin at that time, It is necessary to calculate the possible water sampling amount of the ion exchange device in the future based on data such as the instantaneous flow rate of water. At the time of calculation, it is necessary to calculate separately for cations and anions. Also, the safety factor of the exchange capacity of the ion exchange resin, the expected exchange capacity corresponding to the leakage of seawater, and the regeneration rate In addition, other factors such as the deterioration rate of the resin are taken into consideration, and the point is that the water quality at the inlet side of the ion exchange device must be accurately grasped in real time.

[0009]

By the way, the water quality of the condensate returned to the ion exchange device in a normal nuclear power plant is as follows: total ionic conductivity: about 5.0 μs / cm, cation removal conductivity:
About 0.1 μs / cm, pH: about 9.2, NH ₄ ⁺ concentration: about 540 ppb in terms of NH ₃ , N ₂ H ₅ ⁺ concentration: about 100 ppb in terms of N ₂ H ₄ , Na ⁺ concentration: about 0.005 ppb , Cl ^- concentration: about 0.02 ppb.

The quality of water condensed into the ion exchange device is controlled by measuring the above-mentioned characteristic items. Among these items, the conductivity and pH are generally considered.
Is continuously monitored, the N ₂ H ₄ concentration is analyzed by sampling about once a day, and the NH ₃ concentration is analyzed by sampling about once a week. Further, the Na ⁺ concentration and the Cl ⁻ concentration do not show abnormal values unless a seawater leak occurs in the condenser, so that analysis as a routine work is hardly performed.

The measured values of the total ionic conductivity and the pH are characteristic values for displaying the condensed water quality in real time. However, there are many ionic species in the condensate, and the equivalent conductivity of each ionic species is not all the same and differs depending on each ionic species. Based on this, it is not possible to determine the ion concentrations of all the specific ions in the condensate.

Therefore, even if the conductivity in the condensed water is measured in real time, the total ion load in the condensed water cannot be accurately calculated simply based on the measured value. In other words, in other words, it is not possible to estimate in real time the amount of water that can be collected by each ion exchange device using only the measured value of the conductivity. The present invention solves the above-mentioned problems during the operation of the ion exchange device, and can control the water sampling-regeneration cycle in real time in accordance with the water quality on the inlet side of the ion exchange device. It is an object of the present invention to provide a water sampling and regeneration cycle control device for an ion exchange device capable of maximizing the capacity of a resin.

[0013]

In order to achieve the above object, according to the present invention, there is provided an inlet water quality measuring means which is disposed at a preceding stage of an ion exchange apparatus and measures at least conductivity of raw water sampled; Based on the conductivity signal from the water quality measurement means and the concentration signal of the specific ions in the raw water, calculate the total ion load of the raw water, calculate the resin composition of the ion exchange resin to be regenerated from the calculated value, Predicting and calculating the resin composition when the ion exchange resin is regenerated from the calculated resin composition, and predicting and calculating the outlet water quality and the available water amount of the ion exchange device at the next water sampling based on the predicted calculated value. A water sampling operation means for instructing the ion exchange device to perform a water sampling operation based on a signal of the estimated water sampling possible amount from the calculation means. Dispensing of ion exchanger - regeneration cycle controller is provided.

[0014]

In the control device according to the present invention, first, the conductivity of the raw water sampled is continuously monitored by the inlet water quality measuring means. The conductivity to be measured may be the total ionic conductivity, and it is preferable to measure the cation removal conductivity in consideration of coping with seawater leak in the condenser.

By the way, when there is no sea water leaks in the condenser, the ions of the condensate water at the inlet side of the ion exchanger, the ^{primary, H +, OH -, NH} 4 +, N 2 H
₅ is ^+, the total ionic conductivity of each ion and condensate A
Between (μs / cm), based on the law of Kohlrausch, the formula: A = Λ _H · [H ^+] + lambda _OH · [OH ^-] + lambda _NH4 · [NH ₄ ^+] + Λ _N2H5 · [N ₂ H ₅ ⁺ ]… (1) Λ _H : equivalent ion conductivity of H ⁺ (349.81 cm ² ·
Ω ^-1) Λ _{OH: OH} ^- equivalent ion conductivity (198.30cm ² · Ω
^-1 ) Λ _NH4 : Equivalent ionic conductivity of NH ₄ ⁺ (73.55 cm ² ·
Ω ^-1 ) Λ _N2H5 : equivalent ionic conductivity of N ₂ H ₅ ⁺ (58.70 cm ²
· Omega ^-1) [H ^+]: H ⁺ molarity (g eq / l) [OH ^-]: OH ^- molar concentration (g eq / l) of [NH ₄ ^+]: NH ₄ ⁺ molarity ( g eq / l) [N ₂ H ₅ ^+]: N ₂ H ₅ ⁺ molarity (g eq / l) is satisfied.

In the equation (1), [H⁺] And [OH^-]
Is calculated from the pH value, a daily water quality management item for condensate
can do. And NH_Three, N_TwoH_FourConcentration of
As described above, grasp by periodic analysis work
be able to. NH in water_ThreeAnd N_TwoH_FourOf dissociation
The numbers are each 1.8 × 10^-Five, 8.5 × 10^-7And known
Therefore, for example, N_TwoH_FourAnalysis of concentration
R [N _TwoH_Five ⁺] Can be calculated, and the equation (1)
If the conductivity A is known based on_Four ⁺Calculate
be able to. Conversely, the regular analysis target is NH_ThreeConcentration and
Then, [NH_Four ⁺], [N_TwoH_Five ⁺From equation (1)
Can be calculated.

As described above, by measuring the conductivity of the condensate and measuring the N ₂ H ₄ concentration by periodic analysis, for example, the ions of all the ion species in the condensate can be obtained based on the equation (1). The concentration can be checked. In the control device of the present invention, the above-described conductivity measurement signal and the NH ₃ or N ₂ H ₄ concentration signal obtained by the periodic analysis are input to the calculation means.

In this calculating means, first, the ion concentration of each ion species is calculated based on the equation (1).
The product of the ion concentration and the amount of water flow at the inlet side of the ion exchange device is calculated to calculate the total ion load of the ion exchange resin. Further, a signal relating to the effective resin and the flow-through exchange capacity of the ion exchange resin of the ion exchange apparatus is input to the calculation means, and the product of the two is calculated to calculate the total exchange capacity of the ion exchange resin.

Then, a difference between the total exchange capacity and the total ion load is calculated to calculate a residual exchange capacity, and the residual exchange capacity is divided by the total ion load to predict and calculate a water sampling possible amount of the ion exchange resin. Then, the value is divided by the amount of water flow on the inlet side, and the available water sampling time is estimated and calculated. Further, the resin composition of the ion exchange resin is calculated based on the total ion load of the ion exchange resin. That is, for example, OH type ion exchange resin or N
An information signal relating to the quantitative ratio of each ion exchange resin such as H ₃ type ion exchange resin is obtained.

Then, based on the calculated value of the resin composition of each ion exchange resin, assuming that the ion exchange resin has been subjected to a regeneration treatment, the resin composition of the regenerated ion exchange resin at that time is known. Predicted calculation is performed based on a calculation formula, and further, based on the predicted calculation value, a water extraction amount V that can be used when the regenerated ion exchange resin is used is predicted and calculated by a known calculation formula, and an ion exchange device is used. Outlet water quality is estimated and calculated. The outlet water quality is displayed as, for example, a treated water chloride ion concentration C.

This treated water chloride ion concentration C is equal to a specified value C
If it is higher than ₀ (for example, 20 ppt), the available water collection amount V ₁ (V ₁ <V) satisfying the specified value is calculated again by the calculating means, and the chloride ion concentration C of the treated water is set to the specified value C _0. If it is lower, the available water amount V ₂ (V <V ₂ ) until reaching the specified value C ₀ is calculated again by the calculating means. In any case, the calculating means predicts and calculates the estimated water sampling amount that satisfies the specified value of the outlet water quality.

The information signal relating to the available water sampling amount is input to the water sampling operation means (sequencer), and the sequencer is operated by the input signal, and the above-mentioned estimated water sampling available amount is passed through the ion exchange device. . At the point in time when the actual water sampling amount becomes larger than the predicted water sampling possible amount, the water sampling is stopped and the ion exchange resin is subjected to a regeneration process according to the instruction of the sequencer.

If the predicted water sampling amount calculated by the calculation means is smaller than the minimum water sampling amount set at the time of designing the ion exchange apparatus, the ion exchange resin is again transferred without moving to the water sampling operation by the sequencer. Is performed, and the same calculation is performed again to determine a new predicted water sampling possible amount. If the predicted water sampling amount is smaller than the minimum water sampling amount of the ion exchange resin even by such processing, it is determined that the life of the ion exchange resin has expired, and that the time for replacement has come, and that is determined by means such as an alarm. indicate.

If a seawater leak occurs in the condenser, the concentration of Na ⁺ and Cl ⁻ in the condensate in the ion exchanger increases, and the error in the total ion load calculated by the equation (1) is reduced. growing. In order to solve such a problem, first, a part of the condensed water to the ion exchange device is introduced into a column filled with a cation exchange resin to remove Na ⁺ , and then the cation removal conductivity A '
(Μs / cm). In between the measured conductivity and the ion species, the following ^{formula: A '× 10 -3 = Λ} H · [H ^+] + lambda _OH · [OH ^-] + lambda _Cl · [Cl ^-] ... (2) lambda _Cl: Cl ^- equivalent ion conductivity (76.35cm ² ·
Omega ^-1) [Cl ^-]: Cl ^- molar concentration of (g eq / l) is satisfied. And, as in the case of equation (1),
[H ^{+], -} by seeking from the pH value, [OH]
[Cl ^-] is calculated, by inputting this signal to the calculation means,
What is necessary is just to correct the total ion load.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control device according to the present invention will be described with reference to FIG. 1 taking an example in which a mixed bed type ion exchange device is used. FIG.
, A condensate pump 2 and a condenser 3 are arranged on the upstream side of the ion exchange apparatus 1 in which the cation and anion exchange resins are mixed and housed, and a condensate booster pump 4 is arranged on the downstream side. Is disposed in a closed water passage p connected to a steam generator (not shown) as a whole. The treated water purified by the ion exchange device 1 is sent to the water passage p by the condensate booster pump 4, supplied with the makeup water again by the condenser 3, and then returned to the ion exchange device 1 as condensate water. come. A hydrazine injector 5 and an ammonia injector 6 are interposed between the ion exchange resin 1 and the condensate booster pump 4, and N ₂ H ₄ and NH ₃ are supplied to the circulating raw water from this.

A bypass p ₁ is provided in the middle of the ion exchange device 1 and the condensate pump 2, and the bypass p ₁ is connected to the water quality measuring means 7. A conductivity meter is attached to the water quality measuring means 7, and the total ionic conductivity of the returning condensed water is constantly measured. In addition, this water quality measuring means has another conductivity for measuring the cation removal conductivity of the condensate through a column filled with a cation exchange resin, assuming that a seawater leak occurs in the condenser. Preferably, a meter is mounted. Further, for example, [N
A device for automatically analyzing [H ₄ ⁺ ] or [N ₂ H ₅ ⁺ ] may be added.

The measured value of the total ionic conductivity measured by the inlet water quality measuring means 7 is converted into a standard electric signal S ₁ by a signal converter, for example, and then input to a computer (calculating means) 8. Then, the computer 8 is further supplied with the N ₂ H ₄ concentration (or NH ₃ concentration) which is regularly analyzed, for example, once a day, as a signal S ₂ . When an automatic analyzer for [NH ₄ ⁺ ] or [N ₂ H ₅ ⁺ ] is added to the inlet water quality measuring means, the analysis value is used as a signal S.
_What is necessary is just to input into the computer 8 as ₂ .

The computer 8 calculates the ion concentrations of all the ion species from the input signals S ₁ and S ₂ based on the equation (1), and further calculates the total ion load of the condensate. Then, based on the calculated value, first, the used resin composition of the used anion exchange resin is calculated. Further, it is assumed that the computer 8 has performed a regeneration process based on the calculated value of the resin composition and the regeneration rate and the reverse regeneration rate set for each of the ion exchange resins stored in the computer 8 in advance. Then, the expected resin composition of the anion exchange resin is calculated, and the ratio of the OH exchange resin to the Cl exchange resin is determined.

Then, based on the predicted resin composition after the regeneration, the amount of water that can be taken by the ion exchange resin is calculated as a predicted value, and at the same time, based on the following equation, the salinity of the treated water at the outlet of the ion exchange apparatus 1 is calculated. The substance ion concentration C is calculated.

[0030]

(Equation 1)

(Where, 1: new resin, A: selectivity coefficient of chloride ion, R-Cl (%): ratio of predicted chloride ion exchange resin when regenerated, R-OH (%): regenerated 35.5: atomic weight of chlorine, 10 ⁶ : unit conversion coefficient, 10 ⁻⁷ : hydrogen ion concentration). Note that the computer 8 stores a specified value C ₀ of the treated water chloride ion concentration in the treated water.
The treated water chloride ion concentration C calculated by the equation (3) is compared with a specified value C ₀ , and if C ₀ <C, a water sampling amount that satisfies C ₀ is calculated again. Also, C <
In the case of C ₀ is water sampling can amount required to again reach the C ₀ is calculated. In any case, the predicted water sampling amount V is calculated based on the relationship between the predicted calculation value C and the specified value C _0, and is input to the sequencer 9 as a signal S ₃ .

The sequencer 9 operates on the basis of an input signal S ₃ from the computer 8 and instructs the ion exchange apparatus 1 to supply the above-mentioned predicted water-collectable amount V by a signal S ₄ . When the actual water collection amount exceeds the above-mentioned V value, it is instructed to stop water supply to the ion exchange apparatus 1 and to perform a regeneration process on the ion exchange resin in the apparatus. If the predicted water sampling amount that satisfies the predicted treated water chloride ion concentration calculated by the computer 8 is smaller than the minimum water sampling amount set in the ion exchange device 1, the water sampling operation instructed by the sequencer 9 is performed. Is not performed, the ion exchange resin is regenerated, and the same calculation is performed again to determine a new predicted water sampling possible amount. If the predicted water sampling amount is smaller than the minimum water sampling amount of the ion exchange resin even by such processing, it is determined that the life of the ion exchange resin has expired, and that the time for replacement has come, and that is determined by means such as an alarm. indicate.

As described above, by using the control device of the present invention, the outlet water quality of the ion exchange device can be accurately predicted and calculated, and the available water amount is calculated based on the predicted calculation value. The ability of the ion exchange resin can be utilized to the maximum extent possible. Then, from the comparison between the calculated estimated water sampling possible amount and the actual water sampling amount, it is possible to quantitatively grasp the replacement time of the ion exchange resin.

The control device of the present invention has
Constantly measures the conductivity of the condensate and automatically measures the measurement signal.
At the same time as input to the calculating means,
_TwoH _FourBy also inputting the concentration to the calculation means,
Prediction of ion exchange equipment based on the latest water quality information of condensate water
Available amount of water, scheduled replacement time of ion exchange resin, and regeneration schedule
Time can be grasped in real time.

Further, the ion exchange device 1 is provided with a means 10 for measuring the degree of deterioration of the ion exchange resin.
At 0, the state of deterioration of the ion exchange resin is monitored, and the information S
_By inputting ₅ into the computer 8 and correcting and calculating the above-mentioned chloride ion concentration in the treated water, and determining the available water amount based on the predicted calculation value, a more accurate available water amount can be determined.

As the deterioration degree measuring means 10 in this case, for example, an apparatus described in Japanese Patent Application Laid-Open No. 2-36340 and Japanese Patent Application No. 3-97292 can be used. These means utilize the relationship that when the ion exchange resin is deteriorated, its specific resistance is reduced. Such by deterioration degree measurement unit 10 measures the degraded state of the specific resistance of the ion exchange resin, the resin degradation index was calculated from the measured values, the computer 8 that information as signals S ₅
To enter.

[0037] In the computer 8, to predict calculate the outlet chlorine concentration based on the formula the input signal S ₅ also taking into account (3). In this case, the degradation index is substituted for the 1 / A numerator 1 in the equation (3) and calculated. This predicted calculated value means a treated water chloride ion concentration corresponding to the degree of deterioration of the ion exchange resin. Then, the computer 8 predicts and calculates the amount of water that can be taken based on the predicted calculation value. The predicted calculation value is the amount of water that can be taken in consideration of the deterioration state of the ion exchange resin. . Therefore, it is possible to calculate a possible water sampling amount suitable for the operation cycle from the above-described one calculated and predicted by fixing the resin as a new one.

Although the description has been made by taking an anion exchange resin as an example, the same applies to a case of a cation exchange resin. In that case, the outlet water quality is:

[0039]

(Equation 2)

Based on the above, the computer 8 may make a prediction calculation. In the case of a mixed-bed type desalination tower as in the above embodiment, the anion exchange resin and the cation exchange resin are mixed and operated, but the predicted water sampling for each of the anion exchange resin and the cation exchange resin is possible. The amount is calculated by a computer, and the lower one of the predicted calculated values is used as the predicted water sampling possible amount of the control device of the present invention.

Further, the control device of the present invention is not limited to the above-described mixed-bed ion exchange device for condensate and desalination, but may be applied to a mixed-bed type of pure water or ultrapure water. You may apply to a single bed type. In this case, it goes without saying that the type of ions used as the outlet water quality is appropriately optimal.

[0042]

As is clear from the above description, the water sampling and regeneration cycle control device of the ion exchange device of the present invention can operate the ion exchange device in a state where the capacity of the ion exchange resin is maximized. To In addition, it is possible to grasp the ion concentration of all the ionic species of the condensed condensate and measure its total ion load accurately and in real time. Can be estimated in real time, it is possible to quickly respond to a change in the operation plan of the ion exchange apparatus, and its industrial value is great.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing an example of a control device of the present invention.

FIG. 2 is a schematic view showing a part of a condensate desalination mechanism of a power plant.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ion exchange apparatus 2 Condenser pump 3 Condenser 4 Condenser booster pump 5 Hydrazine injector 6 Ammonia injector 7 Inlet water quality measurement means 8 Calculation means (computer) 9 Water sampling operation means (sequencer) 10 Deterioration of ion exchange resin degree measurement means p water flow path p ₁ bypass

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Susumu Fukue 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo Kurita Kogyo Co., Ltd. (72) Inventor Shuji Yoda 3-4-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo No. Kurita Kogyo Co., Ltd. (72) Inventor Takeshi Tsurumi 3-4-7 Nishi-Shinjuku, Shinjuku-ku, Tokyo Kurita Kogyo Co., Ltd. (56) References JP-A-62-203094 (JP, A) 61-48679 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1/42 B01J 47/14 G21C 19/307 G21F 9/12

Claims (1)

(57) [Claims] 1. Inlet water quality measuring means disposed at the preceding stage of an ion exchange device for measuring at least the conductivity of collected raw water; a conductivity signal from the inlet water quality measuring means and a concentration signal of specific ions in the raw water. Calculate the total ion load of the raw water, calculate the resin composition of the ion exchange resin to be regenerated from the calculated value, and calculate the resin composition when regenerating the ion exchange resin from the calculated resin composition value. Calculating means for predicting and calculating, based on the predicted calculated value, the outlet water quality and the available water amount of the ion exchange device at the time of the next water sampling; and a signal of the predicted available water amount from the calculating means Water sampling operation means for instructing the ion exchange device to perform a water sampling operation on the basis of the following.