Electrodeionization apparatus, maintenance method thereof, and management method for electrodeionization apparatus

Abstract

To provide an electric deionizer with good maintainability and easy water quality control.SOLUTION: An electrode deionizer 9 includes desalination chambers 25 and concentration chambers 26 formed by alternately arranging a plurality of cation exchange membranes 23 and a plurality of anion exchange membranes 24 between electrodes (anode 21 and cathode 22), and the desalination chamber 25 is filled with an ion exchange resin in a mixed or double-layer configuration. The desalination chamber 25 and the concentration chamber 26 are composed of a cell pack consisting of the desalination chamber 25 and the concentration chamber 26 formed by alternately arranging the cation exchange membranes 23 and the anion exchange membranes 24 together with the cation exchange membranes 23 and the anion exchange membranes 24 in a frame, and a plurality of these cell packs are connected to form an integrated structure 9A. This integrated structure 9A is detachable from the electric deionizer 9.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrodeionization apparatus used in a pure water production system, a maintenance method thereof, and a management method thereof, and more particularly to an electrodeionization apparatus that is easy to maintain and to easily manage water quality, a maintenance method thereof, and a management method thereof. [Background technology]

[0002] Conventionally, ultrapure water used in the electronics industry such as semiconductors is produced, for example, by an ultrapure water production system 1 as shown in Fig. 3. This ultrapure water production system 1 is composed of three stages of equipment, namely, a pretreatment device 2, a primary pure water production system 3, and a secondary pure water production system (subsystem) 4. In the pretreatment device 2 of this ultrapure water production system 1, the raw water W is subjected to pretreatment such as filtration, coagulation sedimentation, and a microfiltration membrane, and suspended solids are mainly removed.

[0003] The primary pure water production system 3 has a reverse osmosis membrane device 5 that treats the pretreated water W1, a deaeration membrane device 6, an ultraviolet oxidation device 7, an electrodeionization device 9, and a feed water pump 8 that supplies water to the electrodeionization device 9. The primary pure water production system 3 removes most of the electrolytes, fine particles, live bacteria, etc. from the pretreated water W1 and also decomposes organic matter.

[0004] The subsystem 4 is composed of a sub-tank 10 for storing the primary pure water W2 produced by the primary pure water production equipment 3, an ultraviolet oxidation device 12 for treating the primary pure water W2 delivered from the sub-tank 10 via a pump 11, a non-regenerative mixed-bed ion exchange device 13, and an ultrafiltration (UF) membrane 14 as a particulate removal means, and may further include an RO membrane separation device or the like as necessary. In this subsystem 4, the ultraviolet oxidation device 12 oxidizes and decomposes trace amounts of organic matter (TOC components) contained in the primary pure water W2, and then the non-regenerative mixed-bed ion exchange device 13 processes the water to remove residual carbonate ions, organic acids, anionic substances, and further metal ions and cationic substances by ion exchange. Then, the ultrafiltration (UF) membrane 14 removes particulates to produce ultrapure water W3, which is supplied to a point of use 15, and unused ultrapure water is returned to the sub-tank 10.

[0005] The primary pure water production apparatus 3 used in such an ultrapure water production apparatus 1 is a highly versatile apparatus that is used in various fields such as medicine and food, in addition to the field of ultrapure water production. As shown in Fig. 4, the electrodeionization apparatus 9 has a plurality of cation exchange membranes 23 and anion exchange membranes 24 arranged alternately between electrodes (anode 21, cathode 22) to form deionization chambers 25 and concentration chambers 26 alternately, and the deionization chambers 25 are filled with ion exchangers (anion exchangers and cation exchangers) made of ion exchange resins, ion exchange fibers, graft exchangers, etc., in a mixed or multi-layered form. The concentration chambers 26, the anode chamber 27, and the cathode chamber 28 are also filled with ion exchangers. In general, the deionization chambers 25 and the concentration chambers 26 are filled with a mixed ion exchange resin in which anion exchange resin and cation exchange resin are mixed in a predetermined ratio.

[0006] This electrodeionization apparatus 9 is provided with a water passing means (not shown) for passing feed water (water to be treated) W4 through the deionization chamber 25 to extract treated water (desalinated water) W5, and a concentrated water passing means (not shown) for passing the water to be concentrated through the concentration chamber 26, where the water to be concentrated is introduced into the concentration chamber 26 from the side of the deionization chamber 25 close to the outlet for the desalted water W5, and flows out from the side of the deionization chamber 25 close to the inlet for the feed water W4. That is, the water to be concentrated (desalinated water) W5 is introduced into the concentration chamber 26 from the opposite direction to the flow direction of the feed water W4 in the deionization chamber 25, and concentrated water W6 is discharged. Furthermore, the desalted water W5 is also supplied to the anode chamber 27 and the cathode chamber 28, and the electrode chamber wastewater W7 and W8 are discharged, respectively. Summary of the Invention [Problem to be solved by the invention]

[0007] In the electrodeionization apparatus 9 described above, when the total amount of treated water increases and the ion exchange resin packed in the deionization chamber 25 deteriorates, the operating voltage rises in constant current operation, not only causing an increase in power consumption but also making operation difficult if the voltage rises further. In addition, the ion exchange resin packed in the chamber breaks down and leaks out as fine particles, causing a deterioration in water quality.

[0008] However, even if the performance of the electrodeionization apparatus 9 deteriorates in this way, the current situation is that, because it is difficult to perform maintenance such as regenerating or replacing the ion exchange resin filled in the deionization chamber 25, the entire electrodeionization apparatus 9 must be replaced, and the exterior and electrodes (anode 21, cathode 22) of the electrodeionization apparatus 9 must also be discarded, which is a problem. In addition, since large electrodeionization apparatuses are often made to order, it is difficult to immediately replace the electrodeionization apparatus 9 even if it suddenly becomes necessary to replace it.

[0009] The present invention has been made in view of the above problems, and has an object to provide an electrodeionization apparatus that is easy to maintain and allows easy water quality management. Another object of the present invention is to provide a maintenance method for an electrodeionization apparatus that is easy to maintain and allows for reduced waste. A further object of the present invention is to provide a management method for an electrodeionization apparatus that is easy to maintain and allows easy water quality management. [Means for solving the problem]

[0010] In view of the above-mentioned objects, firstly, the present invention provides an electrodeionization apparatus having a cathode, an anode, and alternating concentrating compartments and deionization compartments formed by arranging a plurality of cation exchange membranes and anion exchange membranes between the cathode and anode, the deionization compartments and the concentrating compartments being filled with ion exchange resin, the deionization compartments and the concentrating compartments having a cell pack structure formed within a frame together with the cation exchange membranes and anion exchange membranes which constitute them, a plurality of such cell packs being connected to form an integral structure in which the concentrating compartments and the deionization compartments are arranged alternately, and the integral structure is detachable from the electrodeionization apparatus (Invention 1).

[0011] According to this invention (Invention 1), when the ion exchange resin packed in the deionization compartment and concentration compartment of the electrodeionization device deteriorates, the performance of the electrodeionization device can be restored by simply removing and replacing the integrated structure made up of the cell pack, and the exterior and electrodes of the electrodeionization device can be used continuously.

[0012] Secondly, the present invention provides a method for maintaining an electrodeionization apparatus having a cathode and an anode, and alternating concentrating compartments and deionization compartments formed by arranging a plurality of cation exchange membranes and anion exchange membranes between the cathode and anode, the deionization compartments and the concentrating compartments being filled with ion exchange resin, the deionization compartments and the concentrating compartments being formed within a frame together with the cation exchange membranes and anion exchange membranes that constitute them, and a plurality of such cell packs being connected to form an integrated structure in which the concentrating compartments and the deionization compartments are arranged alternately, the integrated structure being detachable from the electrodeionization apparatus, wherein the integrated structure is removed from the electrodeionization apparatus and replaced (Invention 2).

[0013] According to this invention (Invention 2), when the ion exchange resin packed in the deionization compartment and concentration compartment of the electrodeionization device deteriorates, the performance of the electrodeionization device can be restored by simply removing and replacing the integrated structure made up of the cell pack, and the exterior and electrodes of the electrodeionization device can be used continuously.

[0014] Thirdly, the present invention provides a method for managing an electrodeionization apparatus comprising a cathode, an anode, and alternating concentrating compartments and deionization compartments formed by arranging a plurality of cation exchange membranes and anion exchange membranes between the cathode and anode, the deionization compartments and the concentrating compartments being filled with ion exchange resin, the deionization compartments and the concentrating compartments being formed within a frame together with the cation exchange membranes and anion exchange membranes that constitute them, a cell pack structure in which a plurality of such cell packs are connected to form an integrated structure in which the concentrating compartments and the deionization compartments are arranged alternately, the integrated structure being detachable from the electrodeionization apparatus, the method comprising the steps of: determining the time to replace the integrated structure based on operation information or treated water information of the electrodeionization apparatus (Invention 3).

[0015] According to this invention (Invention 3), the deterioration state of the ion exchange resin filled in the deionization compartment and the concentration compartment is judged based on the operating information or treated water information of the electrodeionization device, and the time to replace the integrated structure formed by the cell pack is determined. The cell pack is replaced based on this, thereby optimizing the maintenance timing of the electrodeionization device and making it easy to manage the water quality of the electrodeionization device and, ultimately, the pure water production system equipped with it.

[0016] In the above invention (Invention 3), it is preferable that the operation information of the electrodeionization device is an operating voltage of the electrodeionization device (Invention 4).

[0017] According to this invention (Invention 4), when the total amount of treated water increases and the ion exchange resin packed in the electrodeionization device deteriorates, the operating voltage increases during constant current operation. Therefore, by monitoring this operating voltage, it is possible to appropriately determine the time to replace the integrated structure.

[0018] In the above invention (Invention 3), the operation information of the electrodeionization apparatus is preferably a water flow differential pressure calculated from the water supply pressure in the deionization compartment of the electrodeionization apparatus and the treated water pressure (Invention 5).

[0019] According to this invention (Invention 5), when the total amount of treated water increases and the filled ion exchange resin deteriorates, the ion exchange resin breaks down or impurities accumulate, causing the water flow differential pressure to rise. Therefore, by monitoring this water flow differential pressure, the time to replace the integrated structure can be appropriately determined.

[0020] In the above invention (Invention 3), it is preferable that the treated water information of the electrodeionization device is a resistivity or conductivity of the treated water of the electrodeionization device (Invention 6).

[0021] According to this invention (Invention 6), when the total amount of treated water increases and the filled ion exchange resin deteriorates, resulting in a deterioration in water quality, the resistivity or conductivity of the treated water increases. Therefore, by monitoring the resistivity or conductivity and detecting this tendency, the time to replace the integrated structure can be appropriately determined.

[0022] In the above inventions (Inventions 3 to 6), it is preferable to remotely monitor the electrodeionization apparatus by transmitting operating information or treated water information of the electrodeionization apparatus via a transceiver to determine when it is time to replace the integrated structure, and when it is determined that it is time to replace it, to transport a replacement integrated structure to the electrodeionization apparatus and replace it (Invention 7).

[0023] According to the above invention (Invention 7), the condition of the electrodeionization apparatus can be remotely monitored by transmitting operating information or treated water information via a transceiver. The time to replace the integrated structure can be determined based on the monitoring results. By preparing the integrated structure in advance based on this determination result, the integrated structure can be replaced appropriately, and the water quality of the electrodeionization apparatus and a pure water production system equipped with it can be easily managed. Effect of the Invention

[0024] According to the present invention, the deionization compartments and concentration compartments of the electrodeionization device have a cell pack structure formed in a frame together with the cation exchange membrane and anion exchange membrane that constitute them, respectively, and a plurality of such cell packs are connected to form an integral structure in which the concentration compartments and deionization compartments are arranged alternately, and the integral structure is detachable from the electrodeionization device, so that maintenance of the electrodeionization device can be performed and its performance can be restored simply by removing and replacing the integral structure formed by the cell packs, and the exterior and electrodes of the electrodeionization device can be used continuously. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram illustrating an electrodeionization apparatus according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a management system for the electrodeionization apparatus of the embodiment. [Diagram 3] FIG. 1 is a schematic diagram showing an ultrapure water production apparatus as an application example of an electrodeionization apparatus. [Figure 4] FIG. 1 is a schematic diagram showing a conventional electrodeionization apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The electrodeionization apparatus and the maintenance method using the same of the present invention will be described below with reference to the accompanying drawings.

[0027] (Electrodeionization Equipment) The electrodeionization apparatus of the present invention has a cathode, an anode, and concentrating compartments and deionization compartments alternately formed by arranging a plurality of cation exchange membranes and anion exchange membranes between the cathode and the anode, and the deionization compartments and concentrating compartments are filled with ion exchange resin, and is basically the same in configuration as the electrodeionization apparatus shown in Fig. 4. Therefore, in the electrodeionization apparatus shown in Fig. 1, the same components as those in the electrodeionization apparatus shown in Fig. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0028] 1, in this embodiment, the electrodeionization apparatus 9 is configured such that the deionization compartments 25 and the concentration compartments 26 are formed by alternately arranging the cation exchange membranes 23 and the anion exchange membranes 24, and the deionization compartments 25 and the concentration compartments 26 are installed in a frame together with the cation exchange membranes 23 and the anion exchange membranes 24 to form a cell pack, and a plurality of such cell packs are connected to form an integrated structure 9A. This integrated structure 9A is detachable from the electrodeionization apparatus 9. It is preferable to stock in advance a plurality of types of integrated structures 9A formed by connecting a plurality of cell packs, in which the ratio of anion exchange resin to cation exchange resin to be filled in the deionization compartments is variously changed according to the required water quality, etc.

[0029] (Maintenance method for electrodeionization device) A maintenance method for the electrodeionization apparatus 9 as described above will now be described. Maintenance of the electrodeionization apparatus 9 becomes necessary when the quality of the treated water W5 of the electrodeionization apparatus 9 deteriorates, a certain period of use has elapsed, or a certain cumulative amount of treated water has been reached. Conventionally, the electrodeionization apparatus 9 has been replaced as a whole at such times. In contrast, in this embodiment, the integrated structure 9A in which multiple cell packs are connected is detachable, so that maintenance of the electrodeionization apparatus 9 can be performed and its performance can be restored simply by removing and replacing this integrated structure 9A. Moreover, the exterior and electrodes (anode 21, cathode 22) of the electrodeionization apparatus 9 can continue to be used, which helps reduce waste.

[0030] (Method of Managing Electrodeionization Apparatus) A method for managing this electrodeionization apparatus 9 will now be described. Fig. 2 shows a management system for an electrodeionization apparatus 9. In Fig. 2, the electrodeionization apparatus 9 constitutes a part of a pure water production apparatus (primary pure water production apparatus), and a supply pipe 31 and a discharge pipe 32 are connected to the supply side and discharge side of a desalting compartment of the electrodeionization apparatus 9, respectively. The supply pipe 31 is provided with a pressure gauge 33A for measuring the water pressure of the feed water W4, and the discharge pipe 32 is provided with a pressure gauge 33B for measuring the water pressure of the desalted water W5. A voltmeter 34 is provided in the power supply device of the electrodeionization apparatus 9. The measured values ​​of the pressure gauges 33A and 33B and the measured value of the voltmeter 34, which serve as operating information, can be transmitted as operating information D by a transmitter (not shown) provided at a remote location.

[0031] In the management system for this electrodeionization apparatus 9, while the electrodeionization apparatus 9 is treating the supply water W4, information D of the measured values ​​from the pressure gauges 33A and 33B, or information D of the water flow differential pressure based on these, is transmitted to a management facility. When the accumulated amount of water treated by the electrodeionization apparatus 9 increases, the water flow differential pressure increases due to damage to the ion exchange resin, etc., resulting in a deterioration in water quality, so the management facility determines the time to replace the integrated structure 9A made up of multiple connected cell packs based on the information of the water flow differential pressure.

[0032] This determination can be made, for example, by setting a threshold value for the water flow differential pressure in advance, and using the point in time when the water flow differential pressure calculated from the measurement values ​​of the pressure gauges 33A and 33B exceeds this threshold as a reference, and determining whether it is time to replace the integrated structure 9A immediately or after a predetermined period of time has passed. At this time, since the water flow differential pressure may temporarily exceed the threshold, the point in time when the water flow differential pressure exceeds the threshold for a predetermined period of time may also be used as the reference. Furthermore, the point in time when the upward trend of the water flow differential pressure becomes greater than a certain gradient (a certain or greater increase in spring water differential pressure per unit time) may also be used as the reference.

[0033] While the electrodeionization device 9 is treating the supply water W4, measurement value information D from the voltmeter 34 is sent to the management facility. When the accumulated amount of water treated by the electrodeionization device 9 increases, various ions accumulate in the ion exchange resin filled in the deionization compartment, causing the operating voltage to rise when constant current operation is assumed, resulting in increased power consumption and even a stop in the operation of the electrodeionization device 9. Therefore, the management facility determines the time to replace the integrated structure 9A made up of multiple connected cell packs based on the information from the voltmeter 34.

[0034] This determination can be made, for example, by setting a threshold value for the operating voltage in advance, and using the point in time when the measurement value of the voltmeter 34 exceeds this threshold as a reference point, and determining whether it is time to replace the integrated structure 9A immediately or after a predetermined period of time has passed. At this time, since the operating voltage may temporarily exceed the threshold value, the reference point may also be the point in time when the operating voltage exceeds the threshold value for a predetermined period of time. Furthermore, the reference point may also be the point in time when the increasing trend of the operating voltage becomes more than a certain gradient (pressure increase per unit time more than a certain gradient).

[0035] It is preferable to use both the determination of the time to replace the integrated structure 9A based on the measurement values ​​of the pressure gauge 33A and the pressure gauge 33B, and the determination of the time to replace the integrated structure 9A based on the measurement value of the operating voltage by the voltmeter 34, but each may be used alone.

[0036] According to this embodiment, the timing for replacing the integrated structure 9A in which multiple cell packs are connected can be appropriately determined, and water quality management can be easily performed. In particular, by remotely monitoring the electrodeionization apparatus 9, for example, by stocking multiple types of integrated structures 9A in which the ratio of anion exchange resin to cation exchange resin filled in the deionization compartments is changed according to the required water quality, the performance of the electrodeionization apparatus 9 can be restored simply by identifying the type of integrated structure 9A at the management facility and transporting and replacing the integrated structure 9A.

[0037] Although the present invention has been described above based on the above embodiment, the present invention is not limited to the above embodiment and can be modified in various ways. For example, a resistivity meter for measuring the resistivity of the desalted water W5 and a conductivity meter for measuring the conductivity may be provided in the discharge pipe 32, and the resistivity value decreases as the water quality decreases, so that the electrodeionization device 9 may be managed based on the resistivity value of the desalted water W5 as treated water information. Also, a particle counter may be provided in the discharge pipe 32, and the electrodeionization device 9 may be managed based on the number of particles in the desalted water W5 as treated water information. Furthermore, as long as the desalting compartments and the concentration compartments formed by alternately arranging cation exchange membranes and anion exchange membranes can be installed in a frame together with the cation exchange membranes and the anion exchange membranes to form a cell pack, the electrodeionization device may be applied to various electrodeionization devices without any restrictions on the water flow direction. [Explanation of symbols]

[0038] 3 Primary water purification equipment 9. Electrodeionization Equipment Integrated structure with multiple 9A cell packs connected together 21 Anode (electrode) 22 Cathode (electrode) 23 Cation exchange membrane 24 Anion exchange membrane 25 Desalination room 26 Concentration chamber 27 Anode chamber 28 Cathode Chamber 31 Supply pipe 32 Discharge pipe 33A, 33B Pressure gauge 34 Voltmeter W Raw Water W1 Pretreated water (feed water) W2 Primary pure water (demineralized water) W3 Ultrapure water (secondary pure water) W4 Water supply (untreated water) W5 Desalinated water (treated water) W6 Concentrated water W7,W8 Electrode chamber drainage D. Driving Information

Claims

1. An electrodeionization apparatus comprising a cathode, an anode, and a plurality of cation exchange membranes and anion exchange membranes arranged between the cathode and the anode to form alternate concentration compartments and deionization compartments, the deionization compartments and the concentration compartments being filled with an ion exchange resin, The deionization compartment and the concentration compartment are formed in a frame together with the cation exchange membrane and the anion exchange membrane that constitute them, respectively, in a cell pack structure, and a plurality of such cell packs are connected to form an integrated structure in which the concentration compartments and the deionization compartments are arranged alternately, the integrated structure is removable from the electrodeionization device; a transmitter capable of transmitting operation information of the electrodeionization apparatus to a management facility provided at a remote location, the management facility determining the time to replace the integrated structure based on the operation information of the electrodeionization apparatus; The operation information of the electrodeionization apparatus is an operating voltage of the electrodeionization apparatus, and a water flow differential pressure calculated from a water supply pressure in a desalting compartment of the electrodeionization apparatus and a treated water pressure.

2. A maintenance method for an electrodeionization device comprising: a cathode, an anode, and alternating concentrating compartments and deionization compartments formed by arranging a plurality of cation exchange membranes and anion exchange membranes between the cathode and the anode, the deionization compartments and the concentrating compartments being filled with ion exchange resin, the deionization compartments and the concentrating compartments being formed within a frame together with the cation exchange membranes and the anion exchange membranes that constitute them, a cell pack structure in which a plurality of such cell packs are connected to form an integral structure in which the concentrating compartments and the deionization compartments are arranged alternately, the integral structure being detachable from the electrodeionization device, the method comprising the steps of: the electrodeionization apparatus is provided with a transmitter capable of transmitting operation information of the electrodeionization apparatus to a management facility provided at a remote location, and the management facility determines the time to replace the integrated structure based on the operation information of the electrodeionization apparatus; the operation information of the electrodeionization apparatus is an operating voltage of the electrodeionization apparatus and a water flow differential pressure calculated from a water supply pressure in a desalting compartment of the electrodeionization apparatus and a treated water pressure, A maintenance method for an electrodeionization apparatus, comprising removing the integrated structure from the electrodeionization apparatus and replacing it based on the determined time for replacement of the integrated structure.

3. A method for managing an electrodeionization apparatus comprising: a cathode, an anode, and alternating concentrating compartments and deionization compartments formed by arranging a plurality of cation exchange membranes and anion exchange membranes between the cathode and the anode, the deionization compartments and the concentrating compartments being filled with ion exchange resin, the deionization compartments and the concentrating compartments being formed within a frame together with the cation exchange membranes and anion exchange membranes that constitute them, a cell pack structure in which a plurality of such cell packs are connected to form an integrated structure in which the concentrating compartments and the deionization compartments are arranged alternately, the integrated structure being detachable from the electrodeionization apparatus, determining when to replace the integrated structure based on operational information of the electrodeionization apparatus; The method for managing an electrodeionization apparatus, wherein the operation information of the electrodeionization apparatus is an operating voltage of the electrodeionization apparatus, and a water flow differential pressure calculated from a water supply pressure in a desalting compartment of the electrodeionization apparatus and a treated water pressure.

4. 4. The method for managing an electrodeionization apparatus according to claim 3, further comprising the steps of: transmitting operating information of the electrodeionization apparatus via a transceiver; remotely monitoring the electrodeionization apparatus to determine when it is time to replace the integrated structure; and transporting a replacement integrated structure to the electrodeionization apparatus for replacement when it is determined that it is time to replace the integrated structure.

5. Further, the timing of replacing the integrated structure is determined based on treated water information of the electrodeionization device, 4. The method for managing an electrodeionization apparatus according to claim 3, wherein the treated water information of the electrodeionization apparatus is a resistivity or conductivity of the treated water of the electrodeionization apparatus.

6. A method for managing an electrodeionization device as described in claim 5, comprising remotely monitoring the electrodeionization device by transmitting treated water information of the electrodeionization device via a transceiver, determining when to replace the integrated structure, and, when it is determined that it is time to replace it, transporting a replacement integrated structure to the electrodeionization device and replacing it.

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