JP2018114499A - Pure water production apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pure water production apparatus capable of ascertaining the internal state of an ion exchange column.SOLUTION: It is a manufacturing apparatus provided with: an anionic column 50 filled with an anion exchange resin and contacting the water to be treated with an anion exchange resin to produce pure water; at least one pair of electrodes 41a and 41b disposed so as to be in contact with the anion exchange resin and measures conductivity of the anion exchange resin continuously; and analyzing means 10 for calculating the ion concentration in the solid phase in the anion column at an arbitrary time by using a measured value of conductivity of the electrodes 41a and 41b, a load fluctuation of the water to be treated, a regeneration frequency of the anion exchange resin and an amount of the regenerant as parameters, to simulate the state of the anion exchange resin based on the comparison result between the calculation result at the arbitrary time and a measured value of the conductivity.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pure water production apparatus, and in particular, to an ion exchange type pure water production apparatus for producing pure water or ultrapure water used for pharmaceutical production, semiconductor production, boiler water for power generation, foods, and the like. The present invention relates to an available pure water production apparatus.

  2. Description of the Related Art An ion exchange type pure water production apparatus for producing pure water or ultrapure water used for pharmaceutical production, semiconductor production, boiler water for power generation, foods and the like is known. The ion exchange type pure water production apparatus is an apparatus for producing pure water by bringing raw water into contact with an ion exchange resin or the like and removing anion and cation components contained in the raw water by an ion exchange reaction. The ion exchange resin can be used repeatedly by periodically regenerating with an acid and an alkali.

  In recent years, due to higher integration of semiconductors, etc., the purity of pure water required for pure water production equipment has been increased, and the amount of chemicals used for regeneration has been reduced to reduce running costs to the utmost. Yes. However, unless the appropriate regeneration frequency and the amount of the regenerated chemical are adjusted, regeneration failure of the ion exchange resin occurs, and the risk of deterioration of the quality of pure water increases.

  The most orthodox method conventionally used as a method for determining the regeneration frequency is a method in which the ion concentration of the raw water is regarded as constant and the ion exchange resin is regenerated when a certain amount of raw water is passed. However, when the ion concentration of the raw water rises due to seasonal fluctuations, the frequency of regeneration is insufficient, so the quality of the treated water is lowered. If the amount of medicine and the frequency of regeneration are set large in anticipation of seasonal fluctuations, the medicine will be consumed wastefully, and the running cost will increase. In addition, since ion exchange resins deteriorate over time due to dirt and the like, even if there is no seasonal variation, the capacity of the facility is lowered and the quality of treated water is lowered. When the amount of chemicals and the frequency of regeneration are set in consideration of the decrease in equipment capacity, there is a problem that the running cost further increases.

  As a further advanced technology, for example, as described in JP-A-3-181384 (Patent Document 1), the raw water conductivity is measured to calculate the ion load, and the raw water ion load is taken into account. There is a method in which the ion load is obtained and the regeneration frequency is determined. However, the calculation method of the ion load based on the conductivity is limited in accuracy because an error occurs depending on the ion species and pH. In particular, since silica is a weak electrolyte among ions, it is difficult to appear in conductivity, and an error may occur when the ion load is estimated from the conductivity of raw water. Although other analyzers can be installed, the initial cost and running cost increase. Furthermore, as with the prior art described above, ion exchange resins deteriorate over time due to dirt, etc., so that even if there are no seasonal fluctuations, the capacity of the equipment decreases and the quality of the treated water decreases. Considering, even when the technique of Patent Document 1 is used, the reduction of the regeneration frequency and the amount of the regenerant is limited.

  As another conventional technique, a method of suppressing the amount of chemicals used for regeneration by measuring the pH of the regenerated waste liquid of the ion exchange resin and monitoring the amount of the regenerant to be used based on the measured value (Japanese Patent Laid-Open No. Hei. 9-117679 (Patent Document 2)) and a method of measuring silica in treated water with an analyzer. However, each method has a limit in the accuracy of monitoring, and the measuring device is expensive and the equipment size is increased, resulting in an increase in running cost and maintenance cost. In addition, the ion exchange column containing the ion exchange resin has little information obtained by visual observation, and it was difficult to grasp the internal state of the ion exchange column even with a water quality meter connected to the outside of the ion exchange column. .

JP-A-3-181384 JP-A-9-117679

  In view of the above problems, the present invention provides a pure water production apparatus capable of grasping the internal state of an ion exchange column.

  Furthermore, the present invention provides a pure water production apparatus that can treat an ion exchange resin with a more optimal regeneration frequency and amount of regenerant, reduce running costs, and suppress deterioration in the quality of pure water.

  In order to achieve the above-mentioned object, the present inventors diligently examined. As a result, an electrode was placed in contact with the ion exchanger in the ion exchange column filled with the ion exchanger, and the electrode was accommodated in the ion exchange column. It was found that it is effective to continuously measure the conductivity of the ion exchanger.

The present invention completed on the basis of the above knowledge, in one aspect, in a pure water production apparatus for producing pure water using an ion exchange column filled with an ion exchanger, at least a pair of ion exchange columns is provided inside the ion exchange column. An apparatus for producing pure water is provided in which an electrode is disposed in contact with an ion exchanger, and the conductivity of the ion exchanger is continuously measured by the electrode.

  In one embodiment of the pure water producing apparatus according to the present invention, the electrode is disposed on the downstream side of the middle of the inlet and outlet of the ion exchange tower with respect to the water flow direction of the water to be treated.

  In another embodiment, the pure water producing apparatus according to the present invention includes setting the distance between the electrodes to 2 mm or more.

In yet another embodiment, the pure water production apparatus according to the present invention includes that the electrode is arranged inside the ion exchange column so that the cell multiplier of the electrode is ¹ to 10 m ⁻¹ .

  In yet another embodiment, the pure water production apparatus according to the present invention includes disposing two or more pairs of electrodes in the height direction of the ion exchange tower.

  In yet another embodiment, the pure water production apparatus according to the present invention further comprises an analysis means for simulating the state of the ion exchanger in the ion exchange column based on the measured conductivity value.

  In yet another embodiment of the pure water production apparatus according to the present invention, the amount of water to be treated supplied to the ion exchange tower, the amount of chemicals, and the regeneration frequency of the ion exchanger are determined based on the measured conductivity. Control means for controlling at least one of them is provided.

  In yet another embodiment of the pure water production apparatus according to the present invention, the pure water production apparatus includes a two-bed three-column pure water production apparatus comprising a cation tower, a decarboxylation tower, and an anion tower, and the electrode is Arranged at least inside the anion tower.

  In yet another embodiment of the pure water production apparatus according to the present invention, the pure water production apparatus comprises a cation tower, a decarboxylation tower, an anion tower, and a polisher connected to a downstream side of the anion tower. And the electrode is disposed at least inside the polisher.

  ADVANTAGE OF THE INVENTION According to this invention, the pure water manufacturing apparatus which can process an ion exchange resin with the more optimal regeneration frequency and the amount of regeneration agents, can reduce a running cost, and can suppress the deterioration of the quality of pure water is provided.

It is the schematic which shows an example of the pure water manufacturing apparatus which concerns on embodiment of this invention. FIG. 2A shows a cross-sectional view of an electrode seat into which a pair of electrodes are inserted, and FIG. 2B shows a plan view of the electrode seat viewed from the outer surface of the ion exchange tower. It is the schematic showing the relationship between the distance between electrodes of a pair of electrodes, and the particle | grains of an ion exchange resin. It is explanatory drawing showing the arrangement | positioning relationship between the ion exchange tower which concerns on embodiment of this invention, and an electrode. It is a block diagram showing the specific example of an analysis means. It is a flowchart showing an example of the analysis method of the state of the ion exchanger based on the measured value of electrical conductivity. It is the schematic which shows an example of the output result (screen) of an analysis result. It is the schematic showing an example at the time of applying the pure water manufacturing apparatus which concerns on embodiment of this invention to the pure water manufacturing apparatus of a 2 bed 3 tower system. It is a block diagram showing the pure water manufacturing apparatus which concerns on the modification of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is to change the structure and arrangement of components to the following. Not specific.

  As shown in FIG. 1, a pure water production apparatus 1 according to an embodiment of the present invention is a pure water production apparatus 1 that produces pure water by using an ion exchange tower 2 in which an ion exchanger 3 is filled. In the ion exchange tower 2, at least one pair of electrodes 41a and 41b (see FIG. 2 (a)) is disposed so as to be in contact with the ion exchanger 3, and the electrodes 41a and 41b conduct the ion exchanger 3. The rate is measured continuously.

  In the present embodiment, “continuously measured” means not only when the conductivity is constantly measured, but also at regular intervals (every few hours, every month, every year) during the operation period of the pure water production apparatus 1. The aspect also including the case where electrical conductivity is measured regularly is also meant. Since the conductivity of the ion exchanger 3 is continuously measured via the electrodes 41a and 41b, the state (resin performance) of the ion exchanger 3 can be grasped in real time through the conductivity measurement result. As a result, since the performance degradation of the ion exchanger 3 can be determined more quickly, the regeneration time and replacement time of the ion exchanger 3 can be accurately determined.

  The ion exchange tower 2 accommodates the ion exchanger 3 therein, and allows water to be treated to pass through the tower and contact with the ion exchanger 3, thereby removing inorganic dissolved impurities in the water to be treated. The specific configuration is not particularly limited as long as it is possible. As the ion exchanger 3, an ion exchange resin layer filled with a particulate ion exchange resin made of a cation exchange resin, an anion exchange resin or the like is used.

  As shown in FIG. 1, an electrode seat 4 for holding a pair of electrodes 41 a and 41 b (see FIG. 2A) is arranged at the lower part of the outer surface of the ion exchange column 2. In the example of FIG. 2A, the electrodes 41 a and 41 b held in the electrode seat 4 are inserted in a direction that intersects the height direction (water flow direction) of the ion exchange tower 2.

  The electrodes 41a and 41b are formed of a material having corrosion resistance such as stainless steel. As shown in FIG. 2A, the periphery of the electrodes 41 a and 41 b is surrounded by a support material (sleeve) 42. The sleeve 42 is formed of an insulating material, and supports the electrodes 41a and 41b at predetermined positions in the electrode seat 4 so that the tips of the electrodes 41a and 41b are in contact with the ion exchanger 3, and the electrodes 41a and 41b. The contact between each other is prevented. The electrode seat 4 includes a flange 43, and as shown in FIG. 2B, the electrodes 41a and 41b are fixed by a plurality of screws 44 so as to be accommodated at predetermined positions.

  As shown schematically in FIG. 3, the particle size of the ion exchange resin particles 31 used as the ion exchanger 3 is generally about 500 μm, and there are four or more particles 31 between the electrodes. When present, the conductivity of the ion exchanger 3 can be measured stably. Therefore, the interelectrode distance D (see FIG. 2A) of the electrodes 41a and 41b inserted in the ion exchange tower 2 is preferably 2 mm or more. The distance D between the electrodes is preferably 10 mm or less, more preferably 7 mm or less, and even more preferably 5 mm or less because the conductivity may not be stably measured even if it is too far away.

  In order to accurately measure the conductivity of the ion exchanger 3, the distance H (see FIG. 2A) from the inner surface of the ion exchange tower 2 to the tips of the electrodes 41a and 41b is preferably 30 mm or more. The upper limit of the distance H is not particularly limited. However, since the resin constituting the ion exchanger 3 flows, a mechanical load may be applied to the electrodes 41a and 41b and the electrode H may be damaged. Therefore, the distance H is 50 mm or less. It is preferable to do.

  During resin regeneration of the ion exchanger 3, the ion exchange resin constituting the ion exchanger 3 often flows in the form of particles. Therefore, depending on the shape, the resin near the electrodes 41a and 41b may stay, and the conductivity may not be accurately measured. By making the shape of the electrodes 41a and 41b more cylindrical (columnar) than plate-like, the electrodes 41a and 41b can be inhibited from obstructing the movement of particles even during the regeneration of the ion exchange resin, and measurement can be performed with higher accuracy. it can. Although not limited to the following, the diameter of the electrode inserted into the ion exchange tower 2 is preferably 5 mm or more, and specifically about 10 mm.

The solid phase conductivity of the anion exchange resin is generally about 0.1 to 10 mS / cm. Therefore, as the electrodes 41a and 41b for measuring the solid phase conductivity of the ion exchanger 3, the electrodes 41a and 41b are arranged inside the ion exchange column so that the cell multiplier is ¹ to 10 m ^−1. Preferably it is. The “cell multiplier” is represented by the ratio of the electrode area to the distance between the electrodes, and the measurement conditions are calculated according to JIS K0130 “General Rules for Electrical Conductivity Measurement”.

  In order to grasp the state of the ion exchanger 3 more accurately, it is preferable to detect the state of the resin of the ion exchanger 3 on the outlet side than the ion exchanger 3 on the inlet side of the ion exchange tower 2. For this reason, as shown in FIG. 1, the electrodes 41a and 41b are intermediate (50) between the inlet 21 (top of the tower) and the outlet 22 (bottom of the tower) of the ion exchange tower 2 with respect to the direction of water to be treated. %) Is preferably arranged on the downstream side. More preferably, the tips (conductivity detection portions) of the electrodes 41a and 41b are in contact with the ion exchanger 3 at a position that is 70% or more downstream from the inlet (0%) to the outlet (100%). Be placed.

  Alternatively, instead of the electrode seat 4 in FIG. 1, an inner tube 45 arranged inside the ion exchange tower 2 as shown in FIG. 4 can be used as a support material for the electrodes 41a and 41b. The inner tube 45 itself can be used as the electrodes 41a and 41b. By using the inner tube 45, the resin at the center of the ion exchanger 3 and the electrodes 41a and 41b can be brought into contact with each other, so that more accurate conductivity can be measured.

  It is preferable to arrange two or more electrodes 41a and 41b in the height direction of the ion exchange tower. For example, a pair of electrodes is arranged in each of the upstream, middle stream, and downstream regions as viewed from the direction of water flow of the ion exchange tower 2 to measure the upstream, middle stream, and downstream conductivity of the ion exchanger 3. It is preferable. The ion exchanger 3 inside the ion exchange tower 2 changes the properties of the water to be treated with respect to the direction of water flow, so that a concentration gradient of the ion concentration occurs, and the conductivity at the inlet side and the outlet side of the ion exchange tower 2 is high. Although it may change, the resin performance of the ion exchanger 3 can be further improved by arranging a pair of electrodes 41a and 41b at a plurality of locations and measuring the conductivity in the local region of the ion exchanger 3 from a plurality of locations. It is possible to grasp in detail.

  In addition, in order to improve the detection accuracy of the conductivity by the electrodes 41a and 41b, it is preferable that a lining layer (not shown) made of a nonconductive material such as a resin is disposed on the inner surface of the ion exchange tower 2. Alternatively, the ion exchange tower 2 itself may be made of a nonconductive material.

  An AC voltage is preferably applied between the electrodes 41a and 41b. As a result, it is possible to prevent polarization from occurring on the surfaces of the electrodes 41a and 41b and to measure the conductivity of the ion exchanger 3 stably for a long period of time compared to the case where a DC voltage is applied between the electrodes 41a and 41b. Can do.

  As shown in FIG. 1, the pure water production apparatus according to the present embodiment includes an analysis unit 10 that analyzes the measurement values of the electrodes 41 a and 41 b, and the flow rate and chemical amount of water to be treated supplied to the ion exchange tower 2. And a control means 11 for controlling at least one of the regeneration frequency of the ion exchanger.

  The analysis means 10 simulates the state of the ion exchanger 3 based on the measured conductivity value. For example, the analyzing means 10 uses the measured conductivity value to calculate the ion exchange equilibrium (liquid phase-solid phase), the solid phase ion concentration diffusion calculation, and the liquid phase ion concentration diffusion calculation in the ion exchange tower 2. Alternatively, estimation of the ion concentration of the solid phase in the ion exchange column at any flow time with the load fluctuation of the treated water, the regeneration frequency, and the amount of the regenerant as parameters, and the ion concentration diffusion calculation based on the Nernst-Planck equation By performing the above, it is possible to simulate the resin performance of the ion exchange resin constituting the ion exchanger 3 in the ion exchange tower 2 (contaminated state due to contaminants, resin regeneration failure state, aged deterioration, etc.). Specifically, the analysis means 10 calculates the initial state (solid-phase ion concentration) of the ion exchange resin, and then inputs in advance using measured values of conductivity, physical constants, diffusion coefficients, and the like. The calculation is performed sequentially based on the Nernst-Planck equation and the mass balance, using as parameters the load fluctuation of the treated water, the regeneration frequency of the ion exchanger 3, and the amount of the regenerant. Then, compare the calculation result at an arbitrary time with the ion exchange resin state (solid phase ion concentration) based on the conductivity measurement result, correct the calculation, perform recalculation, and confirm that the measurement result is close to the calculation result. The degree of deterioration of the resin can be simulated by checking the condition of the equipment (obtaining solid and liquid phase ion concentrations) and the value of the diffusion coefficient.

  Therefore, for example, as shown in FIG. 5, the analysis unit 10 includes a processing unit 100 for processing measured conductivity values output from at least one pair of electrodes 41 a and 41 b (see FIG. 2A). A storage device 110, an input device 120 for inputting from the operator, and a display device 130 for displaying information necessary for the operator to the operator.

  The processing unit 100 detects a conductivity measurement value measured by the electrodes 41a and 41b, a conductivity detection result by the conductivity detection unit 101, and analysis information (ion) stored in the storage device 110. Exchange flow calculation information (liquid phase-solid phase), ion concentration diffusion calculation information in solid phase, ion concentration diffusion calculation in liquid phase, load fluctuation of treatment water, regeneration frequency, amount of regenerant, and any water flow The state of the ion exchanger 3 packed in the ion exchange column 2 based on the estimated information of the ion concentration of the solid phase in the ion exchange column over time, the ion concentration diffusion information based on the Nernst-Planck equation, etc.) The simulation unit 102 to simulate and the conductivity measured by the electrodes 41a and 41b, or the simulation result simulated from this conductivity, In order to output correction information for changing the operating condition when it is determined that the operating condition of the pure water production apparatus 1 needs to be changed from the comparison result obtained by the comparison unit 103 and the comparison unit 103. The condition changing unit 104 can be provided.

  The control means 11 is a control signal for changing the operating condition of the pure water production apparatus 1 based on the result of the comparison by the comparison unit 103 or a request for changing the operating condition from the operator, specifically, the ion exchange tower 2. A control signal is output for controlling at least one of the amount of treated water supplied, the amount of chemicals, and the regeneration frequency of the ion exchanger.

  According to the pure water producing apparatus 1 according to the embodiment of the present invention, the analysis unit 10 uses the measured values of the conductivity measured by the electrodes 41a and 41b, so that the solid phase and the liquid phase in the ion exchange tower 2 are measured. Since the state can be simulated in real time, the internal state in the ion exchange column 2 and the state (resin performance) of the ion exchanger 3 packed in the ion exchange column 2 can be accurately grasped. Furthermore, from the measurement results of the conductivity of the ion exchanger 3 continuously measured, the change of the conductivity over time is captured, and the comparison unit 103 constantly compares it with the simulation result. Since correction can be performed, it is possible to accurately grasp the state of the entire facility. Thereby, since the state of an installation is visualized accurately, reliability improves.

  The operation of the pure water production apparatus so far has been based on a certain amount of chemical and water flow. However, according to the present embodiment, the analysis means 10 can reflect all the operating conditions in the simulation. Therefore, the amount of chemicals, the amount of water flow, and the regeneration frequency can be set freely according to the operating conditions.

  In addition, according to the pure water production apparatus according to the present embodiment, the amount of water flow, the amount of chemicals, and the frequency of regeneration are parameters (variables), so that restrictions on equipment operation (production schedule, operator attendance time, chemical delivery) According to restrictions such as the schedule), it is possible to set operation conditions more in line with the operation management conditions at the site. In addition, by reflecting the optimum operating conditions in real time, it is possible to reduce the excessive supply of chemicals and unnecessary resin regeneration steps, thereby reducing the running cost.

  The operation method of the pure water manufacturing apparatus according to the embodiment of the present invention will be described below using the flowchart of FIG. The following operation method is merely an example, and it is needless to say that there are various other operation methods using the pure water production apparatus according to the present embodiment.

First, necessary information (initial conditions, equipment conditions, operating conditions, etc.) is stored in the storage device 110 via the input device 120. As initial conditions, a solid phase ion concentration (X _OS ), a liquid phase ion concentration (X _OL ), etc. for defining the initial state of the ion exchange column 2 are input. As equipment conditions and operating conditions, resin amount V [m ³ ], flow rate Q [m ³ / h], raw water ion load CO [eq / m ³ ], regeneration conditions (frequency [h / cycle], chemical concentration [eq] / M ³ ]), physical constants (diffusion coefficients D [m ² / sec], ion valence, etc.) and the like are input.

  Next, in step S1, an AC voltage is applied between at least one pair of electrodes 41a and 41 arranged in the ion exchange tower 2, and conductivity (electric conductivity) is measured. 5 detects the measured value of the conductivity measured by the electrodes 41a and 41.

  In step S <b> 2, the simulation unit 102 uses the measured conductivity value detected by the conductivity detection unit 101 to check the state of the ion exchanger 3, for example, the ion concentration gradient of the solid phase and liquid phase in the ion exchange column 2. Is used to simulate the usage state of the ion exchanger 3. For example, based on the detected conductivity and the analysis information stored in the storage device 110, ion exchange equilibrium calculation (between liquid phase and solid phase), ion concentration diffusion in the solid phase, ion concentration diffusion in the liquid phase Differentiation and integration calculations can be performed. Specifically, for example, the ion exchange tower 2 is divided into about 100 stages in the height direction, and the liquid phase ion concentration is calculated sequentially from the vicinity of the inlet. Furthermore, using the Nernst-Planck equation and the diffusion coefficient D as analysis information, for each element divided in the height direction, the ion exchanger 3 which is a solid phase and the ions in the liquid phase around it. Simulation is performed for concentration diffusion (diffusion concentration of ions). The ion concentration of the ion exchange resin can be simulated, for example, by dividing the ion exchange resin into about 20 parts and performing differential calculation for each divided element. The simulation result is stored in the storage device 110. For example, information as shown in FIG. 7 is displayed on the display device 130 as necessary, so that the operator can easily confirm the state inside the ion exchange column 2. .

  In step S <b> 3, the conductivity detection unit 101 detects again the measured value of conductivity measured by the electrodes 41 a and 41. In step S4, the comparison unit 103 reads out the simulation result stored in the storage device 110 and compares it with the conductivity measured by the electrodes 41a and 41b (or the simulation result obtained from this conductivity), and the ion exchange tower. It is determined whether or not the operation condition 2 is necessary to be corrected. If it is determined that the operating condition of the pure water production apparatus 1 needs to be changed, in step S5, the condition changing unit 104 outputs correction information for changing the operating condition, and the process proceeds to step S6. If it is not necessary to change the operating conditions of the pure water production apparatus 1, the process directly proceeds to step S6.

  In step S6, it is determined whether or not the analysis of the deionized water production apparatus 1 is to be terminated by the condition changing unit 104. If the analysis is not finished, steps S2 to S6 are repeated again.

  In the conventional pure water production apparatus, even if a meter is installed outside the ion exchange tower 2, it is difficult to grasp the details of the inside of the ion exchange tower 2 in detail. Operating conditions were set with a margin. According to the method for producing pure water according to the present embodiment, since the conductivity of the ion exchanger 3 can be measured based on at least one pair of electrodes 41a and 41b, the ion concentration of the ion exchanger 3 can be determined from the conductivity. And the like for each region, the internal state of the ion exchange tower 2 can be grasped in detail. In general, the internal state of the ion exchange column 2 has parameters that make it difficult to completely model the flow of water and the like, but in this embodiment, the conduction by the electrodes 41a and 41b that are continuously detected. A more accurate calculation result can be obtained by correcting the rate detection result against the past simulation result or test result. For example, FIG. 7 shows the output result of the calculation result, and the ion concentration distribution in the height direction of the solid phase and liquid phase of each tower constituting the pure water production apparatus is shown on the left side of the screen, and on the right side of the screen. Shows the ion concentration distribution in a cross section perpendicular to the height of the ion exchange resin. The operator can grasp the internal conditions of each tower constituting the pure water production apparatus in real time through a screen as shown in FIG. 7, for example.

(Modification)
Note that the analysis unit 10 may estimate the resin performance of the ion exchanger 3 by paying attention only to the temporal change in conductivity without performing the complicated simulation as described above. For example, (1) when the conductivity of the ion exchanger 3 is measured every predetermined period while water to be treated is passed through the ion exchange tower 2, the resin regeneration step Alternatively, a method of exchanging the resin, (2) measuring the conductivity immediately after resin regeneration, and comparing the conductivity value with the conductivity immediately after the previous resin regeneration, the conductivity decreases to a predetermined value or more A method of regenerating the resin again or urging the replacement of the resin, and (3) recording the change in the measurement result of the conductivity over time, resulting in a decrease in the conductivity due to long-term use. There are methods to evaluate the deterioration of equipment depending on the condition.

That is, the water electric conduction medium in the ion exchange tower 2 is often ions, and the electric conductivity of water increases as the concentration of ions increases. On the other hand, pure water varies in purity from distilled water to a grade called ultrapure water, but as the purity increases, the ion concentration decreases and the electrical conductivity decreases. When the purity of pure water is increased, only electric conduction by H ⁺ and OH ⁻ generated by dissociation of water is obtained, and approaches the theoretical conductivity of pure water 0.056 μS / cm (0.0056 mS / m).

The organic polymer ion exchange resin has, for example, a styrene divinylbenzene copolymer as a skeleton, the cation exchange resin has a sulfonic acid group, and the anion exchange resin has a functional group such as a quaternary ammonium group. In addition, the quaternary ammonium group is a salt in which an acid, an alkali, a metal ion, a chloride ion or the like is arranged with H ⁺ or OH ⁻ as a counter ion. The ion concentration in the ion exchanger 3 varies depending on the concentration of the functional group, but is a relatively high concentration solid acid, solid alkali or salt such as 1 mol / L to 10 mol / L. As described above, since the ion exchanger 3 has a high ion concentration and a high mobility, the ion exchanger 3 has a relatively good ion mobility, and particularly in a state containing moisture, the conductivity of the ion exchanger 3. The conductivity in pure water is several to several hundred times higher than that in pure water.

Since ions are electrically conductive media in the ion exchanger 3, the conductivity of the ion exchanger varies greatly depending on the mobility and diffusivity of the counter ions. In particular, the conductivity of the ion exchanger varies greatly depending on the ion species, ion size, and ion adsorption state. H ⁺ and OH ⁻ are high in mobility from size and mass, and the counter ion of the ion exchanger is H ⁺ and OH. ^In the case of-, the conductivity of the ion exchanger increases.

The ion exchange resin used in the pure water production equipment is regenerated by acid or alkali, returns the counter-ion removed by ion exchange to H ⁺ or OH ⁻ , and ion exchanges the ions contained in the raw water in the water sampling process. Manufactures water. In other words, the ion exchanger immediately after regeneration is filled with H ⁺ or OH ⁻ counter ions, and the ion exchanger has high conductivity, and the ions contained in the raw water are gradually ion-exchanged by ion exchange reaction after sampling. When taken into the body, the conductivity tends to be low.

  In particular, silica and boron are weak electrolytes, and have the property of polymerizing and growing into large molecules. Therefore, the ion exchanger adsorbing silica and boron has a particularly low electrical conductivity. In the two-bed, three-column (2B3T) type pure water production system, the anion that leaks most easily from the anion exchange column is silica or boron, so the conductivity of the anion exchanger is an index for estimating the adsorption state of silica or boron. It becomes. For example, in the 2B3T type pure water production apparatus, the water to be treated is particularly close to pure water, and an electrode is installed near the outlet of the anion tower where the ion concentration is low, and the conductivity of the anion exchanger is measured to accurately measure silica or boron. The adsorption state of the anion exchanger can be grasped, and the state of the anion exchanger can be grasped.

  The ion exchanger is contaminated by polymer electrolytes, humic substances, organic substances, etc. contained in the raw water, and the performance is lowered. Although these contaminants may be ionized to some extent, they tend to be difficult to regenerate once they are incorporated into the ion exchanger by ion exchange because of their large molecular weight and low mobility. Furthermore, since the mass of the contaminant is large, the conductivity of the contaminated ion exchanger tends to be low. Therefore, by measuring the conductivity of the ion exchanger, the degree of deterioration of the ion exchanger can be measured, and the replacement time of the ion exchanger can be determined.

  In addition to the method described above, periodically sampling the resin and liquid phase at several points in the height direction of the resin tower, directly measuring the state of the resin, and directly measuring the ion concentration of the liquid phase, By reflecting the result on the above simulation result, the accuracy of the simulation can be further improved.

(Application examples)
The ion exchange tower 2 described above can be suitably used for a 2B3T multi-bed tower pure water production apparatus or a mixed bed type pure water production apparatus. For example, as shown in FIG. 8, the pure water production apparatus according to this embodiment includes a two-bed, three-column pure water production apparatus comprising a cation tower 30, a decarboxylation tower 40, and an anion tower 50, and is not shown. However, it includes that the electrodes 41a and 41b are disposed at least inside the anion tower 50, and the electrode seat 4 accommodating the electrodes 41a and 41b is provided in the anion tower 50. By measuring the electrical conductivity in the anion tower 50 having a higher quality of water to be treated than the cation tower 30 for treating the raw water with a large amount of impurities, the state of the ion exchanger accommodated in the interior can be reduced with a small number of devices. The accuracy of evaluation can be improved. Needless to say, the electrodes 41 a and 41 b may be inserted into the cation tower 30 and the decarboxylation tower 40. Of course, a conductivity meter 61 for measuring the conductivity of the raw water may be further arranged.

  Alternatively, as shown in FIGS. 9A and 9B, as the pure water production apparatus according to the present embodiment, a polisher 70 is further disposed on the downstream side of the anion tower, and electrodes 41 a and 41 b are disposed inside the polisher 70. May be further arranged. The polisher 70 may be either a mixed bed type as shown in FIG. 9A or a form in which the cation polisher 71 and the anion polisher 72 are separately provided as shown in FIG. 9B.

  As described above, the present invention is expressed by the invention specifying matters in the scope of claims appropriate from the above disclosure, and can be modified and embodied without departing from the spirit of the invention in the implementation stage.

  Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

Example 1
In a counter-current regeneration type two-bed / three-column pure water production apparatus, a conductivity meter was installed in the anion tower to measure the conductivity of the anion exchange resin. As the cation exchange resin, 650C × 3000 L of cation exchange resin manufactured by Dow Chemical was used. As the anion exchange resin, an anion exchange resin 550A × 3000L (resin layer height after regeneration of 2300 mm) manufactured by Dow Chemical was used. The diameter of the cation tower was 1200 mm, and the diameter of the anion tower was 1300 mm. The raw water is treated with well water (electric conductivity 23 mS / m, silica concentration 60 mg / L as SiO ₂ ), and the quality of the treated water (pure water) is 0.2 mS / m or less, silica concentration 100 μg / L as SiO _2. The water flow rate was 50 m ³ / h.

  As an anion resin measurement electrode, two cylindrical stainless steel electrodes having a diameter of 10 mm are opposed to each other in the electrode seat 4 shown in FIG. 2A, and the resistance between the electrodes is measured. Conductivity was measured. The tip of the electrode (measurement end) is located at a position of 2000 mm with respect to the water flow direction, the distance D between the electrodes is 6 mm, and the electrode insertion depth (from the inner surface of the ion exchange tower 2 to the tips of the electrodes 41a and 41b) The distance H) was 40 mm. In measuring the conductivity, a converter WBM-100 manufactured by Toa DKK Co., Ltd. was used, and the conductivity was measured every 3 hours. The results are shown in Table 1.

  As shown in Table 1, when the water flowed for 21 hours, the resin conductivity of the anion tower changed as shown in the table below. Since the decrease in conductivity was measured after 15 hours of operation, it was determined that the ion exchange band (the layer of ion exchange resin that had undergone ion exchange and became salt type) was moving in the direction of water flow. It was decided to perform playback at the timing when the drop occurred.

  By performing regeneration using this method, it is possible to detect a suitable regeneration start timing even when the load of raw water fluctuates, eliminating the need for regeneration in anticipation of variation, and reducing the frequency of regeneration. Thus, it was possible to operate about 30% less than the amount of regenerated chemical used compared with the conventional pure water production apparatus.

(Example 2)
Using the same pure water production apparatus as in Example 1, in the process of repeating regeneration / water flow / regeneration of the ion exchange resin, the conductivity was measured immediately after the water flow after completion of the regeneration of the resin body. The results are shown in Table 2.

  RUN NO. Only 4, it was found that the electrical conductivity immediately after passing through the water after regeneration was low and the regeneration was poor. According to the second embodiment, by managing the electrical conductivity immediately after passing water after regeneration, the soundness of regeneration can be confirmed, and it is possible to prevent water quality from being deteriorated due to poor regeneration, and stable operation of the apparatus. Became possible.

(Example 3)
Using the same pure water production apparatus as in Example 1, the conductivity was measured every 6 months. The results are shown in Table 3.

  It was confirmed that the electrical conductivity of the resin was decreased year by year, and the electrical conductivity was not sufficiently recovered even after regeneration, and it was confirmed that the performance of the resin deteriorated over time. Since a decrease in conductivity was confirmed after 36 months, a regeneration operation was performed by increasing the amount of the regenerated drug, and then it was confirmed that the conductivity recovered and the resin performance recovered to some extent. However, when the operation was continued, the conductivity was reduced to about half of the initial value after 60 months, and it was confirmed that the performance of the resin was greatly lowered. Therefore, the resin was replaced. As described above, according to the present embodiment, it is possible to grasp in real time the deterioration in performance of the resin over time, and it is possible to perform appropriate resin regeneration operation and periodic resin replacement. In comparison, the running cost could be reduced by 30% to 40%.

DESCRIPTION OF SYMBOLS 1 ... Pure water manufacturing apparatus 2 ... Ion exchange tower 3 ... Ion exchanger 4 ... Electrode seat 10 ... Analyzing means 11 ... Control means 30 ... Cation tower 31 ... Particle 40 ... Decarbonation tower 41a, 41b ... Electrode 42 ... Sleeve 43 ... Flange 45 ... Inner pipe 50 ... Anion tower 61 ... Conductivity meter 70 ... Polisher 71 ... Cation polisher 72 ... Anion polisher 100 ... Processing unit 101 ... Conductivity detection unit 102 ... Simulation unit 103 ... Comparison unit 104 ... Condition changing unit 110 ... Storage device 120 ... Input device 130 ... Display device

Claims (6)

An anion exchange resin filled inside, an anion column for producing pure water by bringing treated water into contact with the anion exchange resin;
At least one pair of electrodes disposed in contact with the anion exchange resin and continuously measuring the conductivity of the anion exchange resin;
Using the measured value of the conductivity by the electrode, the load fluctuation of the treated water, the regeneration frequency of the anion exchange resin and the amount of the regenerant as parameters, the ion concentration in the solid phase in the anion tower at an arbitrary water flow time is determined. An apparatus for calculating pure water, comprising: an analyzing means for calculating and simulating the state of the anion exchange resin based on a comparison result between a calculation result at an arbitrary time and a measured value of the conductivity.   The pure water manufacturing apparatus according to claim 1, wherein the analyzing means includes simulating the degree of deterioration of the anion exchange resin.   The control device according to claim 1, further comprising a control unit that controls at least one of a flow rate of water to be treated supplied to the anion tower, a chemical amount, and a regeneration frequency of the anion exchange resin based on the measured value of the conductivity. 2. The pure water production apparatus according to 2.   The pure water according to any one of claims 1 to 3, wherein the electrode is disposed downstream of the middle of the inlet and outlet of the anion tower with respect to the direction of water flow of the treated water. manufacturing device.   The pure water manufacturing apparatus of any one of Claims 1-4 including arrange | positioning the said electrode two or more places in the height direction of the said anion tower.   The pure water production apparatus according to any one of claims 1 to 5, wherein the pure water production apparatus includes a two-bed three-column pure water production apparatus comprising a cation tower, a decarboxylation tower, and the anion tower.