JP2009142724A - Electrical deionizer and deionized water producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical deionizer (EDI) capable of obtaining high quality water at high removal rate of impurities and without being affected by variation in quality of raw water, and a deionized water producing method. <P>SOLUTION: In a desalting section of the EDI, a first small desalting section and a second small desalting section which are divided in the direction of the thickness of the desalting section by an intermediate ion exchange membrane 26 arranged between a cation exchange membrane 30 and an anion exchange membrane 22 are formed, and desalting divisions divided in parallel to the direction of desalting section thickness are formed in each of the first small desalting section and the second small desalting section. In the deionized water producing method, the EDI is used and water to be treated is caused to pass through a plurality of the desalting divisions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrical deionized water production apparatus and a deionized water production method used in various fields such as semiconductor manufacturing field, pharmaceutical manufacturing field, power generation field such as nuclear power and thermal power, food industry, and research facilities. .

2. Description of the Related Art Conventionally, as a method for producing deionized water, a method for performing deionization by passing water to be treated through an ion exchange resin is known. However, in this method, when the ion exchange resin is saturated with ions, it is necessary to perform a regeneration treatment with a chemical. In recent years, in order to eliminate such disadvantages in processing operation, an electric deionized water production apparatus (hereinafter referred to as EDI) which does not require regeneration of an ion exchanger by a drug has been put into practical use. This EDI is an apparatus for producing pure water that combines electrophoresis and electrodialysis. An ion exchanger is filled between the anion exchange membrane and the cation exchange membrane, an anode electrode and a cathode electrode are arranged outside the ion exchange membrane, and a water to be treated is applied to the ion exchanger layer with a DC voltage applied to the electrodes. By passing water, ions in the water to be treated are adsorbed by the ion exchanger, migrated to the membrane surface by electrophoresis, and electrodialyzed by the ion exchange membrane to remove it into the concentrated water. .
Conventional typical EDI has a plurality of demineralization chambers formed by disposing an ion exchanger between an anion exchange membrane and a cation exchange membrane through a concentration chamber serving as a chamber from which ions are excluded. It has a structure with plus and minus electrodes.

Until now, various attempts have been made for the purpose of improving the quality of deionized water obtained by EDI and removing impurity ions with power saving. In the desalting chamber, since the filling method and the filling amount of the ion exchanger to be used are determined by the required water quality of the deionized water, there is a limit in reducing the electrical resistance of the desalting chamber. Therefore, measures are often taken to reduce the electrical resistance of the concentrating chamber. For example, Patent Document 1 discloses a method of reducing the electrical resistance in the concentration chamber by adding and supplying an electrolyte to the concentration chamber.
On the other hand, Patent Document 2 discloses two small desalination chambers defined by a cation exchange membrane on one side, an anion exchange membrane on the other side, and an intermediate ion exchange membrane located between the cation exchange membrane and the anion exchange membrane. Discloses an EDI having a two-cell structure of a desalting chamber in which a desalting chamber is formed by filling an ion exchanger. The EDI is provided with concentration chambers on both sides of the desalting chamber via the cation exchange membrane and the anion exchange membrane. The desalting chamber and the concentration chamber are divided into an anode chamber having an anode, a cathode chamber having a cathode, It is arranged between. In the production of deionized water, water to be treated is introduced into one small desalination chamber (first small desalination chamber) while applying a voltage, and then the effluent from the small desalination chamber is used as the other small desalination chamber. In addition to flowing into the chamber (second small desalination chamber), concentrated water is allowed to flow into the concentration chamber to remove impurity ions in the water to be treated to obtain deionized water. According to the EDI having such a structure, the ion exchanger filled in at least one of the two small desalting chambers is, for example, an anion exchanger alone or a single bed form such as only a cation exchanger. Or, it can be a mixed bed form of anion exchanger and cation exchanger, and it can be set to an optimum thickness for reducing the electric resistance and obtaining high deionization performance for each type of ion exchanger. it can.
Japanese Patent Laid-Open No. 9-24374 Japanese Patent No. 3385553

However, although the conventional techniques can reduce the electrical resistance in the desalination chamber or the concentration chamber, removal of impurities and prevention of scale generation have not yet been sufficient. In addition, there is a problem that the quality of the deionized water obtained is not stable due to fluctuations in the raw water quality of the treated water.
An object of the present invention is to provide an EDI capable of removing impurities at a high removal rate and obtaining a high water quality (raw water resistance) without being affected by fluctuations in the raw water quality, and a method for producing deionized water.

As a result of intensive studies on the reduction of ion removal ability and the generation of scale in the conventional EDI, the present inventor has obtained the following knowledge.
In the conventional two-cell structure of the desalination chamber, depending on the arrangement of the ion exchanger and the intermediate ion exchange membrane, the silica is interposed between the first small desalination chamber and the second small desalination chamber via the intermediate ion exchange membrane. In addition, ions such as carbonic acid and sodium circulate, and there is a problem that it is difficult to discharge to the concentration chamber. For example, when silica circulates, the amount of silica brought in from the water to be treated and the amount of silica brought in from the adjacent desalting chamber are added together, and actually more than silica brought in from the water to be treated. The amount of silica is to be treated. As a result, silica cannot be completely removed, leading to problems such as leakage into deionized water or extremely increasing electrical resistance.

In the case of a structure in which the first small desalting chamber is filled with a cation exchanger and the second small desalting chamber is filled with an anion exchanger, as the cation component is removed in the first small desalting chamber, The pH of the solution tends to be acidic, and the H ⁺ concentration increases. For this reason, the current efficiency to the cation component to be removed, such as Na ⁺ and Ca ⁺ , decreases, and the cation component cannot be reduced below a certain concentration. And since the 2nd small desalination chamber was not filled with the cation exchanger, there existed a problem that it would leak to deionized water as it is. Furthermore, since the cation component removal ability of the anion exchange membrane constituting the second small desalting chamber is not 100%, the cation component once moved to the concentration chamber is very small, but the second component passes through the anion exchange membrane. It moves back to the small desalination chamber. And since the 2nd small desalination chamber is not filled with the cation exchanger, there exists a phenomenon that a cation component leaks in deionized water as a result.

In the case of a structure in which the first small desalting chamber is filled with an anion exchanger and the second small desalting chamber is filled with a cation exchanger, as the anion component is removed in the first small desalting chamber, The pH of the solution tilts toward the alkali side, and the OH ⁻ concentration increases. Therefore, Cl ^- or carbonate, such as silica, reduces the current efficiency of the anionic component to be removed, it can not be reduced anionic component constant concentration below. And since the 2nd small desalination chamber was not filled with the anion exchanger, there existed a problem that it would leak to deionized water as it is. Further, since the anion component removal ability of the cation exchange membrane constituting the second small desalting chamber is not 100%, the anion component once moved to the concentration chamber is very small, but the second component passes through the cation exchange membrane. It moves backward to the two small desalting chambers. And since the anion exchanger is not filled in the second small desalting chamber, there is a phenomenon that an anion component leaks into the deionized water as a result.

Further, in the EDI having a one-cell structure in which the desalting chamber is not divided by the intermediate ion exchange membrane, there are the following problems when a plurality of types of ion exchangers are stacked and filled in the desalting chamber. The electric resistance is greatly different between the single bed form of the stacked cation exchanger, the single bed form of the anion exchanger, and the mixed bed form of the cation exchanger and the anion exchanger. For this reason, electricity flows only through the resin layer having a lower electrical resistance, and there is a phenomenon that the ion removal rate in the resin layer having a higher electrical resistance is extremely reduced.
In addition, H ⁺ generated at the contact point between the anion exchange membrane and the cation exchanger contributes to regeneration of the cation exchanger, but OH ⁻ moves to the concentration chamber and does not perform any function. is there. This phenomenon will be described with reference to FIG. FIG. 4 is a schematic diagram of an EDI deionization module 220 having a one-cell structure. As shown in FIG. 4, the deionization module 220 includes a demineralization chamber 224 formed between the cation exchange membrane 222 and the anion exchange membrane 230, and concentration chambers 234 formed on both sides of the demineralization chamber 224. Between the chamber and the anode chamber. In the desalting chamber 224, a desalting layer 224a filled with an anion exchanger and a desalting layer 224b filled with a cation exchanger are formed. When the water to be treated is passed through the desalting chamber 224, H ⁺ is generated on the desalting chamber 224 side and OH ⁻ is generated on the concentrating chamber 234 side at the interface between the anion exchange membrane 230 and the cation exchanger of the desalting layer 224b. To do. H ⁺ generated on the desalting chamber 224 side contributes to the regeneration of the cation exchanger in the desalting layer 224 b, while OH ⁻ generated on the concentration chamber 234 side is not any ion exchanger in the desalting chamber 224. Does not contribute to regeneration. Similarly, OH ⁻ generated at the interface between the cation exchange membrane 222 and the anion exchanger filled in the desalting layer 224a contributes to the regeneration of the anion exchanger in the desalting layer 224a, but is generated on the concentration chamber 234 side. H ⁺ does not contribute to the regeneration of any ion exchanger in the desalting chamber 224.
The present invention has been made based on the above findings.

That is, the EDI of the present invention is provided with a desalination chamber in which a space defined by a cation exchange membrane on one side and an anion exchange membrane on the other side is filled with an ion exchanger, and the cation exchange membrane and the anion Concentration chambers are provided on both sides of the desalting chamber via an exchange membrane, and the desalting chamber and the concentration chamber are disposed between an anode chamber having an anode electrode and a cathode chamber having a cathode electrode. In the deionization chamber, an intermediate ion exchange membrane disposed between the cation exchange membrane and the anion exchange membrane is provided in the demineralization chamber in the thickness direction of the demineralization chamber. A partitioned first small desalting chamber and a second small desalting chamber are formed, and the first small desalting chamber and the second small desalting chamber are parallel to the thickness direction of the desalting chamber, It is characterized in that a multi-stage desalting zone is formed. The intermediate ion exchange membrane may be a single membrane of a cation exchange membrane or an anion exchange membrane, or a dual membrane having both a cation exchange membrane and an anion exchange membrane.
In the EDI of the present invention, the first small desalting chamber may be filled with a cation exchanger in a single bed form, and the second small desalting chamber may be filled with an anion exchanger in a single bed form. The thickness of the first small desalting chamber may be smaller than the thickness of the second small desalting chamber, the thickness of the first small desalting chamber is 4 to 16 mm, and The thickness of the second small desalting chamber is preferably 8 to 22 mm.
The first small desalting chamber is divided into two in parallel with the thickness direction of the desalting chamber to form a first small desalting chamber first desalting zone and a first small desalting chamber second desalting zone. The second small desalting chamber is divided into two in parallel with the thickness direction of the desalting chamber, so that a second small desalting chamber first desalting zone and a second small desalting chamber second desalting zone are formed. Water to be treated is a first small desalting chamber, a first desalting zone, a second small desalting chamber, a first desalting zone, a first small desalting chamber, a second desalting zone, and a second small desalting chamber. It is preferable to be controlled to flow in the order of two desalting zones, the concentration chamber is preferably filled with an anion exchanger in a single-bed form, and the cathode chamber and the anode chamber are The ion exchanger is packed in an anion exchanger or a single bed form of a cation exchanger, or in a mixed bed form of an anion exchanger and a cation exchanger, or between an anode or an anode and a partition membrane. A laminate composed of an on-exchanger layer and a cation-exchanger layer is preferably arranged, and the cathode electrode and / or the anode electrode is divided for each corresponding desalting zone, and a current applied to each electrode. May be controlled separately.

  The method for producing deionized water according to the present invention is a method for producing deionized water using the EDI, wherein the water to be treated is circulated through a plurality of demineralized zones.

  According to the EDI and deionized water production method of the present invention, impurities can be removed at a high removal rate while preventing scale generation, and high water quality can be obtained without being affected by fluctuations in raw water quality.

The EDI of the present invention will be described with an example, but is not limited to this embodiment.
An example of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of an EDI 10 according to this embodiment. FIG. 2 is a perspective view of the deionization module 20 of the EDI 10 of this embodiment. For convenience of explanation, the constituent members of the deionization module 20 are shown at regular intervals. In the actual deionization module 20, the constituent members are in close contact with each other.
As shown in FIG. 1, the EDI 10 of the present embodiment has a plurality of deionization modules 20 disposed adjacent to each other via a concentration chamber 34 between a cathode chamber 12 and an anode chamber 16. The cathode chamber 12 is formed by the spacer 13 sandwiched between the cathode electrode 14 and the partition film 32. The anode chamber 16 is formed by a spacer 17 sandwiched between the anode electrode 18 and the partition film 32. The cathode electrode 14 and the anode electrode 18 are each connected to a power source (not shown). The cathode chamber 12 is connected to an electrode water inflow line B1 and an electrode water outflow line B2. The anode chamber 16 is connected to an electrode water inflow line B3 and an electrode water outflow line B4. B2 and the electrode water inflow line B3 are connected by a pipe (not shown). The concentration chamber 34 is formed by filling an anion exchange resin in a space formed by disposing the deionization module 20 apart. Further, a concentrated water inflow line C1 and a concentrated water outflow line C2 are connected to the concentrating chamber 34.

In the deionization module 20, a deionization chamber D is formed by filling an ion exchanger in a space formed by arranging the cation exchange membrane 22 and the anion exchange membrane 30 to face each other. The desalting chamber D is divided into two in the thickness direction of the desalting chamber D by an intermediate ion exchange membrane 26 disposed between the cation exchange membrane 22 and the anion exchange membrane 30, and is placed on the cation exchange membrane 22 side. A first small desalting chamber D1 is formed, and a second small desalting chamber D2 is formed on the anion exchange membrane 30 side.
The deionization module 20 will be described in more detail with reference to FIG. The deionization module 20 is arranged in the order of a cation exchange membrane 22, a frame body 24, an intermediate ion exchange membrane 26, a frame body 28, and an anion exchange membrane 30. The frame body 24 has ribs 24a that bisect the hollowed interior space. Similarly, the frame body 28 has a rib 28a that bisects the hollowed interior space. The cation exchange membrane 22 is disposed on one side of the frame body 24 so as to be in close contact with the frame body 24 and the rib 24a, and the intermediate ion exchange membrane 26 is disposed on the other side of the frame body 24 with the frame body 24 and the rib 24a. It arrange | positions so that it may closely_contact | adhere. Thus, the space formed inside the frame body 24 is filled with the cation exchange resin to form the first small desalting chamber first desalting zone D11 and the first small desalting chamber second desalting zone D12. Has been. Further, the intermediate ion exchange membrane 26 is disposed on one side of the frame body 28 so as to be in close contact with the frame body 28 and the rib 28a, and the anion exchange membrane 30 is disposed on the other side of the frame body 28 with the frame body 28 and the rib 28a. It is arranged to be in close contact with. Thus, the space formed inside the frame body 28 is filled with the anion resin, and the second small desalting chamber first desalting zone D21 and the second small desalting chamber second desalting zone D22 are formed. ing.
Further, the deionized module 20 is connected to the treated water inflow line A1 and the deionized water outflow line A2. The cation exchange membrane 22, the frame body 24, the intermediate ion exchange membrane 26, the frame body 28, and the anion exchange membrane 30 have communication holes 21a-21d, 23a-23f, 25a-25d, 27a- 27f and 29a to 29d are provided, respectively. In addition, the frames 24 and 28 are provided with water passages for water to be communicated with the communication holes 23a, 23b, 23d, 23e, 27b, 27c, 27e, and 27f and the desalted zone.

  Roughly classified as ion exchange membranes, a homogenous membrane formed by impregnating a raw material monomer solution into a reinforcing body and then polymerized to form a homogeneous whole, and a non-homogeneous material obtained by grinding and pulverizing together with a polyolefin resin capable of dissolving and molding the ion exchange resin There are two types of membranes. The cation exchange membrane 22 and the anion exchange membrane 30 in this embodiment are not particularly limited, and should be selected according to the ease of production of EDI, the quality of water to be treated, the quality of water required for deionized water, the amount of treatment, and the like. Can do.

  The intermediate ion exchange membrane in this embodiment is an anion exchange membrane. The intermediate ion exchange membrane 26 is not particularly limited, and the same one as the anion exchange membrane 30 can be used.

The cation exchange resin filled in the first small desalting chamber D1 is not particularly limited, and can be selected according to the quality and amount of water to be treated, the quality of deionized water, and the like. Mention may be made of cation exchange resins and weakly acidic cation exchange resins. For example, as a commercial product, Amberlite (trade name) manufactured by Rohm and Haas can be cited.
The anion exchange resin filled in the second small desalting chamber D2 is not particularly limited, and can be selected according to the quality and amount of treated water, the quality of deionized water, etc. Anionic exchange resins, strong basic anion exchange resins, and weak basic anion exchange resins. For example, as a commercial product, Amberlite (trade name) manufactured by Rohm and Haas can be cited.
The anion exchange resin filled in the concentration chamber 34 is not particularly limited, and can be selected according to the quality of the water to be treated or deionized water, and the anion charged in the second small desalting chamber D2. The same as the exchange resin can be used.

The frames 24 and 28 are not particularly limited as long as they have insulating properties and do not leak treated water. For example, frames made of resin such as polyethylene, polypropylene, polyvinyl chloride, ABS, polycarbonate, noryl, etc. Can be mentioned.
The thickness of the frames 24 and 26 is not particularly limited, and can be set according to the desired thickness of the first small desalting chamber D1 and the second small desalting chamber D2.
The rib 24a partitions the first small desalting chamber first desalting zone D11 and the first small desalting chamber second desalting zone D12, prevents the passage of treated water in both desalting zones, and is insulative. If it is the material which has this, it will not specifically limit, The material similar to the frame bodies 24 and 28 can be used. The rib 28a can be the same as the rib 24a.
Moreover, when the area of each desalting zone is large, you may provide a support body in the space where the frame bodies 24 and 28 were hollowed out. By providing the support, it is possible to prevent the cation exchange membrane 22, the intermediate ion exchange membrane 26, and the anion exchange membrane 30 from being curved and the amount of ion exchange resin in each desalting zone from becoming uneven. is there. The support is not particularly limited as long as it is a material that has insulating properties and does not hinder the flow of water to be treated. For example, polyethylene, polypropylene, polyvinyl chloride, ABS, polycarbonate, noryl, etc., provided with slits. The resin-made support body can be mentioned.

The thickness of the desalting chamber D is not particularly limited, and the optimum thickness is determined according to the type and filling form of the ion exchanger filled in the first small desalting chamber D1 or the second small desalting chamber D2. It is preferable to do. In EDI10 of this embodiment, compared with the conventional EDI, the desalting chamber D can be set thickly. Since the first small desalting chamber D1 and the second small desalting chamber D2 have a single bed form of the cation exchanger and a single bed form of the anion exchanger, the electrical resistance in the desalting chamber D can be kept low. For this reason, if the thickness of the desalting chamber D is increased, the current efficiency for the ionic components in the water to be treated can be improved while suppressing an increase in electrical resistance.
From the above viewpoint, for example, the thickness of the desalting chamber D is preferably determined in the range of 12 to 36 mm, and is preferably determined as appropriate in the range of 16 to 28 mm.

The thicknesses of the first small desalting chamber D1 and the second small desalting chamber D2 can be determined in consideration of the quality of the water to be treated and deionized water, and the both may be the same thickness. It may be different. When the thicknesses of the first small desalting chamber D1 and the second small desalting chamber D2 are different, it is preferable to increase the thickness of the second small desalting chamber D2 filled with the anion exchange resin. Normal raw water to be treated water contains more anion components than cation components, and efficiently removing the anion components in the treated water provides high-quality deionized water, This is because it is effective in preventing the occurrence of scale in the concentration chamber 34.
Although the thickness of the 1st small desalination chamber D1 is not specifically limited, It is preferable to set in the range of 4-16 mm. If it is less than 4 mm, sufficient residence time cannot be secured, and the water quality tends to deteriorate. On the other hand, if it exceeds 16 mm, the increase in electrical resistance becomes remarkable, and not only the effect of improving the current efficiency is reduced, but also the deionization module becomes difficult to mold.
The thickness of the second small desalting chamber D2 is not particularly limited, but is preferably set in the range of 8 to 22 mm. If it is less than 8 mm, sufficient residence time cannot be secured, and the water quality tends to deteriorate. On the other hand, if it exceeds 22 mm, the increase in electrical resistance becomes remarkable, and not only the effect of improving the current efficiency is reduced, but also the deionization module becomes difficult to mold.

The cathode electrode 14 is not particularly limited as long as it functions as a cathode, and examples thereof include plate-like stainless steel and mesh-like stainless steel. The anode 18 is not particularly limited as long as it functions as an anode. However, since chlorine is generated at the anode, one having chlorine resistance is preferable. For example, a noble metal such as platinum, palladium, iridium, or a net-like or plate-like electrode obtained by coating the noble metal on titanium or the like can be given.
Moreover, the cathode electrode 14 and the anode electrode 18 may each be installed one each, and may be divided | segmented into 2 or more pairs according to the magnitude | size of each desalination zone.

The spacer 13 is not particularly limited as long as the electrode water can be circulated and the cathode chamber 12 having a desired width can be formed. The spacer 13 is made of a resin such as polyethylene, polypropylene, polyvinyl chloride, ABS, polycarbonate, noryl. Examples thereof include a mesh and a lattice-like frame material having water permeability.
The thickness of the spacer 13 is not particularly limited, but can be selected according to the desired space of the cathode chamber 12. For example, it is preferable to select in the range of 0.3 to 4 mm. The spacer 17 can be the same as the spacer 13.

  The partition membrane 32 is not particularly limited as long as it is an ion exchange membrane, and can be selected in consideration of the quality of water to be treated, the operating conditions of the EDI 10, and the like. Either a cation exchange membrane or an anion exchange membrane is used. May be. Among these, it is preferable to select a cation exchange membrane that is advantageous in terms of resistance to oxidizing agents.

A method for producing deionized water using EDI 10 will be described with reference to FIGS. In addition, this invention is not limited to the following embodiment.
Electrode water is caused to flow into the cathode chamber 12 from the electrode water inflow line B 1, and a DC voltage is applied between the cathode electrode 14 and the anode electrode 18. Next, the concentrated water is introduced into the concentration chamber 34 from the concentrated water inflow line C1 in an upward flow. Next, the water to be treated is caused to flow into the deionization module 20 from the water to be treated inflow line A1. The treated water that has flowed into the deionization module 20 circulates through the ion exchange resin in the demineralization chamber D, and the deionized water from which the ionic components have been removed flows from the deionized water outflow line A2. leak.

The flow path of the water to be treated in the deionization module 20 will be described in detail with reference to FIG. The treated water flows from the treated water inflow line A1 through the communication hole 21a provided in the cation exchange membrane 22, and reaches the communication hole 23a provided in the frame body 24. It flows into the salt zone D11. The treated water that has flowed into the first small desalting chamber first desalting zone D11 circulates while diffusing in the cation exchange resin, and the cation components (Na ⁺ , Ca ²⁺ , Mg ²⁺ etc.) are mainly contained in the cation exchange resin. To be adsorbed. The adsorbed cation component is attracted to the cathode side, passes through the cation exchange membrane 22, and moves to the concentration chamber 34. Here, when the removal of the cation component in the for-treatment water proceeds, the pH in the for-treatment water shifts to the acidic side, and the H ⁺ concentration that is a competing ion of the cation component increases. As a result, the current efficiency with respect to the cation component is lowered, and the cation component hardly reaches a certain concentration or less. And to-be-processed water distribute | circulates the 1st small desalination chamber 1st desalination zone D11 in the state in which a certain amount of cation component remained, and reaches the communicating hole 23b. The treated water flows from the communication hole 23b through the communication hole 25a provided in the intermediate ion exchange membrane 26, the communication hole 27a provided in the frame body 28, and the communication hole 29a provided in the anion exchange membrane 30. The communication hole 29b is reached by a pipe that is not connected.
Next, the water to be treated reaches the communication hole 27b from the communication hole 29b and flows into the second small desalination chamber first desalination zone D21. The treated water that has flowed in flows through the anion exchange resin while diffusing and mainly contains anion components (Cl ⁻ , HCO ₃ ⁻ , CO ₃ ²⁻ , SiO ₂ (silica often takes a special form). , And so on, which are different from general ions. The adsorbed anion component is attracted to the anode side, passes through the anion exchange membrane 30 and moves to the concentration chamber 34. At this time, since the water to be treated flows into the second small desalting chamber first desalting zone D21 in a state where the pH is shifted to the acidic side, the concentration of OH ⁻ which is a competitive ion of the anion component is low. For this reason, the anion component is removed very well. The treated water that circulated through the second small desalting chamber first desalting zone D21 circulates from the communication hole 27c to the communication holes 25b, 23c, and 21b, and reaches the communication hole 21c through a pipe (not shown). In addition, in the stage which distribute | circulated the 2nd small desalination chamber 2nd desalting zone D21, pH of to-be-processed water is a neutral area | region.

Subsequently, the water to be treated reaches from the communication hole 21c to the communication hole 23d and flows into the first small desalting chamber second desalting zone D12. The treated water that has flowed into the first small desalting chamber second desalting zone D12 flows while diffusing in the cation exchange resin, and mainly the cation component is removed again. Here, even if the removal of the cation component in the for-treatment water proceeds, the concentration of H ⁺ is lower than that in the first small desalting chamber first desalting zone D11. For this reason, current efficiency becomes high and the removal of the cation component in to-be-processed water is performed favorably. And the to-be-processed water which distribute | circulated the 1st small desalination chamber 2nd desalination area D12 distribute | circulates the communication holes 25c, 27d, and 29c from the communication hole 23e, and reaches the communication hole 29d by piping which is not shown in figure. At this stage, ionic components contained in the water to be treated are generally removed. However, among the anion components removed in the second small desalination chamber first desalination zone D21, carbonate ions are gasified in the concentration chamber 34 and permeate through the cation exchange membrane 22 to form the first small desalination chamber. It may move backward to D1. For this reason, the anion component is removed again in the second small desalting chamber second desalting zone D22.
The treated water reaches the communication hole 27e from the communication hole 29d and flows into the second small desalination chamber second desalting zone D22. The treated water that has flowed into the second small desalting chamber second desalting zone D22 flows while diffusing in the anion exchange resin, mainly the anion component is removed again, and reaches the communication hole 27f. In this way, the cation component and the anion component are removed from the water to be treated and flows from the communication hole 27f through the communication holes 25d, 23f, and 21d, and flows out from the deionized water outflow line A2 as deionized water.

  On the other hand, the concentrated water flowing into the respective concentration chambers 34 from the concentrated water inflow line C1 circulates in an upward flow while diffusing through the ion exchanger filled in the concentration chamber 34, and is moved from each desalting zone. An ionic component is taken in and discharged from the concentrated water outflow line C2.

The electrode water that has flowed into the cathode chamber 12 from the electrode water inflow line B1 flows in the cathode chamber 12 in an upward flow and flows to the electrode water outflow line B2. Then, the electrode water that has flowed into the electrode water outflow line B2 flows into the anode chamber 16 from the electrode water inflow line B3 via a pipe (not shown), and circulates in the anode chamber 16 in an upward flow. It is discharged from the outflow line B4. During this time, the electrode water takes in H _{2 and the} like generated from the cathode electrode 14 and Cl ₂ and O _{2 and the} like generated from the anode electrode 18 and discharges them outside the EDI 10.

Although the to-be-processed water is not specifically limited, The water etc. which processed the water which removed the turbid component of industrial water and well water with the turbidity membrane with the reverse osmosis (RO) membrane, etc. are mentioned.
The amount of liquid passing through the desalting chamber D of the water to be treated is not particularly limited, and can be determined in consideration of the ability of the EDI 10 and the quality of the water to be treated. The liquid flow rate is represented by space velocity (SV), and the unit of SV is the flow rate (L) circulated in one hour with respect to the unit volume (LR) of the ion exchange resin. ^-1 (same in the following). In the present embodiment, SV = 30 to 300 L / LR · h ⁻¹ is preferable. If the SV is too high, the ion removal performance will decrease, the differential pressure will increase due to the increase in the liquid flow rate (LV) that occurs with the increase in SV, which will cause damage to the deionization module 20, and will cause operational difficulties. It is not preferable because it causes it. Here, LV is a flow rate per unit area, which is a linear velocity expressed in m / h.
On the other hand, if the SV is too low, the flow distribution to each deionization module is not performed properly, resulting in deionization modules with sufficient demineralization treatment and deionization modules with insufficient demineralization treatment. May adversely affect performance.

  The flow rate of the concentrated water in the concentration chamber 34 is not particularly limited, and can be determined in consideration of the ability of the EDI 10, the quality of the water to be treated, and the treatment amount. The concentrated water has the purpose of diffusing ions that have moved to the concentration chamber 34 into the concentrated water and flowing out of the EDI 10. From this, it is preferable to determine the flow rate of the concentrated water in relation to the flow rate of the treated water, the ion concentration of the treated water, and the recovery rate of the deionized water. For example, the following formula (1) It is preferable to determine the flow rate of the concentrated water so that the expressed concentration ratio is 3 to 20. The concentration ratio according to the following equation (1) is defined on the assumption that the same raw water is used for the water to be treated and the concentrated water, and all the ions in the desalting chamber D are transferred to the concentration chamber 34.

If the flow rate of the concentrated water is too small, the concentration diffusion of ions transferred to the concentration chamber 34 becomes uneven, the concentration polarization layer on the surface of the ion exchange membrane becomes thick, and scale may be generated. On the other hand, if the flow rate of the concentrated water is too large, the recovery rate of deionized water decreases, which is not preferable.
The concentrated water is not particularly limited, and water from the same water source as the water to be treated may be used as the concentrated water, or deionized water or pure water may be used.

The current to be applied is not particularly limited and is preferably determined in consideration of the quality of the water to be treated, the scale of the EDI 10, and the like. In addition, when the cathode electrode 14 and the anode electrode 18 are divided into two or more according to each desalting zone, the divided electrode pairs may be applied with different current values. This is because the water quality can be improved by selecting an optimal current value according to the quality of the water to be treated.
The flow rate of the electrode water is not particularly limited, and is preferably determined according to the applied voltage or the like. For example, it is preferable to set in the range of 5 to 200 L / h, preferably 30 to 100 L / h. If the flow rate of the electrode water is too small, it will be difficult to sufficiently discharge the generated H ₂ , O ₂ , and Cl ₂ gases, and if the flow rate of the electrode water is too large, the recovery rate is lowered, which is not preferable.

According to the EDI 10 of this embodiment, the first small desalting chamber D1 and the second small desalting chamber D2 are further divided into two to form a desalting zone, whereby each desalting zone has a different function. Things will be possible. As a result, high water quality can be obtained because four-stage treatment can be performed without increasing the number of deionization modules 20. Further, the ion exchange resins in both desalting zones of the first small desalting chamber D1 are unified, and the ion exchange resins in both desalting zones of the second small desalting chamber D2 are unified, so that the current orthogonal directions Can be prevented from being displaced.
Moreover, it can suppress that the cation component of the concentration chamber 34 reversely moves to the 2nd small desalination chamber D2 because the concentration chamber 34 is filled with the anion exchanger. On the other hand, although the reverse movement of the anion component of the concentration chamber 34 to the desalting chamber D occurs, the place of reverse movement is the first small desalting chamber first desalting zone D11 or the first small desalting zone. It is a salt chamber second desalting zone D12. Accordingly, the anion component can be sufficiently removed in the second small desalting chamber first desalting zone D21 or the second small desalting chamber second desalting zone D22 through which the water to be treated flows thereafter. Therefore, the water quality can be improved.
By using an anion exchange membrane for the intermediate ion exchange membrane 26, OH ⁻ and H ⁺ generated at the contact point between the cation exchange resin in the first small desalting chamber D1 and the anion exchange membrane of the intermediate ion exchange membrane 26 are respectively Since it can contribute to the regeneration of the first small desalting chamber D1 and the second small desalting chamber D2, there is little waste in terms of current efficiency. This point will be described with reference to a schematic diagram of the deionization module 20 of FIG. As shown in FIG. 3, when the water to be treated is passed through the desalting chamber D, at the interface between the intermediate ion exchange membrane 26 and the cation exchange resin of the first small desalting chamber D1, the first small desalting chamber D1 is located. H ⁺ and OH ⁻ are generated on the second small desalting chamber side D2. H ⁺ generated on the first small desalting chamber D1 side contributes to the regeneration of the cation exchange resin in the first desalting chamber D1, and OH ⁻ generated on the second desalting chamber D2 side is the second desalting chamber. It contributes to the regeneration of the anion exchange resin of D2. Then, surplus H ⁺ and OH ^{− in} the regeneration of the cation exchange resin and the anion exchange resin move to the concentration chamber 34 on the counter electrode side. In this way, waste can be reduced in terms of current efficiency, so that water quality can be improved.

In the concentration chamber 34, hardness components such as Mg ²⁺ and Ca ²⁺ that have moved from the demineralization chamber D stay in a portion with high pH near the anion exchange membrane 30, and the demineralization chamber of the adjacent deionization module 20. There is a case where scale is generated by reacting with carbonate ions that have moved from D. However, in this embodiment, since the concentration chamber 34 is filled with an anion exchange resin, hardness components such as Mg ²⁺ and Ca ²⁺ move in the concentrated water, while anion components such as carbonate ions are anion exchange resin. Move through the layers. For this reason, in the concentration chamber 34, the hardness component and carbonate ions are not in contact with a high concentration, and the effect of preventing the generation of scale is high.
In addition, by appropriately setting the thickness of the first small desalination chamber D1 filled with the cation exchange resin and the second small desalination chamber D2 filled with the anion exchange resin, low electrical resistance, high current efficiency, Low pressure loss can be realized. And as above-mentioned, the circulation of the ionic component in to-be-processed water can be prevented, and the improvement of raw | natural water resistance can be aimed at.
Furthermore, in the present embodiment, since four-stage processing can be performed in one deionization module 20, a significant cost reduction can be realized as compared to using a plurality of deionization modules 20 in multiple stages.

The EDI and the deionized water production method of the present invention are not limited to the above-described embodiment.
In the above-described embodiment, the ion exchange resin is filled in the desalting chamber D, but the ion exchanger filled in each small desalting chamber is not particularly limited as long as it has an ion exchange function. In addition to ion exchange resins, for example, ion exchange fibers, monolithic porous ion exchangers and the like can be mentioned. Among these, an ion exchange resin that is most versatile and hardly causes a gap between the membrane and the ion exchanger even when wrinkles or the like occur in the ion exchange membrane is preferable. These may be used alone or in combination of two or more.
In the above-described embodiment, the first small desalting chamber D1 is filled in a single bed form of cation exchange resin, and the second small desalting chamber D2 is filled in a single bed form of anion exchange resin. However, the filling form of the ion exchanger to be filled is not particularly limited. Therefore, the ion exchanger can be packed in any form of an anion exchanger single bed, a cation exchanger single bed, a mixed bed of an anion exchanger and a cation exchanger, or a combination thereof. Further, different forms of ion exchangers may be filled in each desalting zone provided in the small desalting chamber. However, from the viewpoint of suppressing the unevenness of the current density distribution and obtaining a high water quality, it is preferable that the filling form of the ion exchanger for each small desalting chamber is unified.

  In the above-described embodiment, an anion exchange membrane is used for the intermediate ion exchange membrane 26. However, the intermediate ion exchange membrane is a cation exchange membrane or a dual membrane in which both an anion exchange membrane and a cation exchange membrane are arranged. Also good. The dual membrane means a membrane in which the ion exchange membrane is divided in parallel with the thickness direction and the polarities of the divided regions are different. For example, an ion exchange membrane is divided into two, an anion membrane is provided on the upper side of the device, and a cation membrane is provided on the lower side of the device. The area ratio between the anion exchange membrane and the cation exchange membrane in the duplex membrane can be appropriately determined depending on the quality of the water to be treated and the purpose of treatment. In addition, it is preferable to select the kind of intermediate ion exchange membrane according to the water quality of to-be-processed water and the water quality calculated | required by deionized water.

  In the above-described embodiment, the concentration chamber 34 is filled with an anion exchange resin, but is not limited thereto. For example, an ion exchange fiber, a monolithic porous ion exchanger, or the like may be filled, or a single bed form of a cation exchanger or a mixed bed form of a cation exchanger / anion exchanger may be filled. Furthermore, a spacer may be disposed without filling the ion exchanger. However, from the viewpoint of suppression of scale formation in the concentrating chamber, it is preferable to fill with an ion exchanger, and it is particularly effective to suppress scale generation by filling with an anion exchanger.

  In the above embodiment, the cathode chamber 12 and the anode chamber 16 are provided with spacers, but may be filled with an ion exchanger. The ion exchanger to be filled is not particularly limited, and examples thereof include ion exchange resins, ion exchange fibers, and monolithic porous ion exchangers. The cation exchanger or anion exchanger may be packed in a single bed form or a mixed bed form of a cation exchanger / anion exchanger. Furthermore, a laminate composed of an anion exchanger layer and a cation exchanger layer may be arranged between the cathode 14 or the anode 18 and the partition film 32. This is because the electrical resistance can be reduced by filling the cathode chamber 12 and the anode chamber 16 with the ion exchanger.

In the above-described embodiment, the water to be treated is divided into the first small desalting chamber first desalting zone D11 (cation exchange resin), the second small desalting chamber first desalting zone D21 (anion exchange resin), and the first small desalting zone. The desalting chamber second desalting zone D12 (cation exchange resin) and the second small desalting chamber second desalting zone D22 (anion exchange resin) are circulated in this order, but the distribution route is limited to this. is not. For example, the second small desalting chamber first desalting zone D21 (anion exchange resin), the first small desalting chamber first desalting zone D11 (cation exchange resin), the second small desalting chamber second desalting zone D22. The treated water may be circulated in the order of (anion exchange resin) and first small desalting chamber second desalting zone D12 (cation exchange resin). However, from the viewpoint of obtaining high water quality, it is preferable to distribute the water to be treated as in the above-described embodiment.
Moreover, the distribution direction of the water to be treated in each desalting zone may be an upward flow or a downward flow.

  In the above-described embodiment, the concentrated water is circulated in the upward flow. However, the flow direction of the concentrated water is not particularly limited, and may be a downward flow. Further, the relationship with the flow direction of the water to be treated is not particularly limited, and may be the same as the flow direction of the water to be treated, or may be in the opposite direction, or in a direction orthogonal to each other. There may be.

  In the above-described embodiment, the electrode water is an upward flow, but it may be a downward flow. In addition, the electrode water is not limited to flowing into the anode chamber 16 after flowing through the cathode chamber 12, but may flow from the anode chamber 16 to the cathode chamber 12, or the electrode water may be supplied from the electrode water outflow line B2. The electrode water may be discharged and supplied to the electrode water inflow line B3 from another water source.

In the above-described embodiment, each small desalting chamber is approximately divided into two to form a desalting zone. However, the size of each desalting zone may be the same or different. It can be set accordingly.
In the above-described embodiment, each small desalting chamber is divided into two to form a desalting zone, but the number of desalting zones formed in each small desalting chamber may be three or more.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, it is not limited to an Example.
<Conductivity / specific resistance>
For water quality evaluation, conductivity and specific resistance were used. In the case of water containing no impurities, the theoretical value of conductivity in water at 25 ° C. is 0.055 μS / cm, and the theoretical value of specific resistance is 18.2 MΩ · cm. As for the water quality of deionized water, the specific resistance approaches 18.2 MΩ · cm, and the higher, the higher the water quality. Deionized water quality was evaluated with specific resistance.
The conductivity was measured using a conductivity meter (873CC, manufactured by FOXBORO). The specific resistance was measured using a specific resistance meter (873RS, manufactured by FOXBORO).

<Silica concentration>
Water quality was evaluated by measuring the silica concentration, which is an index of EDI processing performance. The silica concentration was measured by molybdenum blue absorptiometry using a spectrophotometer (U-3010, manufactured by Hitachi High-Technology Corporation).

Example 1
EDI-1 similar to EDI10 shown in FIG. In addition, three deionization modules were arrange | positioned in EDI-1, and the thing similar to the deionization module 20 shown in FIG. 2 was used for each deionization module.
Using the obtained EDI-1, deionized water was produced for 2000 hours under the following operating conditions. After 2000 hours of continuous operation, the specific resistance, silica concentration, and average applied voltage of EDI-1 obtained were measured, and the results are shown in Table 1. The hardness of the water to be treated is a value measured with an atomic absorption spectrophotometer (SpectrAA, manufactured by Varian), and the total carbonic acid concentration is a value measured with a wet ultraviolet oxidation TOC analyzer (model 900, manufactured by SIEVERS). is there.
<EDI-1 specification>
(1) Cation exchange membrane: Astom Co., Ltd. (2) Intermediate ion exchange membrane: Astom Co., Ltd. anion exchange membrane (3) Anion exchange membrane: Astom Co., Ltd. (4) First demineralized salt chamber thickness: 8 mm
(5) Second desalination chamber thickness: 12 mm
(6) Desalted zone dimensions: width 100mm x height 140mm
(7) Ion exchanger filled with the first small desalting chamber: Cation exchange resin (Rohm and Haas) single bed configuration (8) Ion exchanger filled with the second small desalting chamber: Anion exchange resin (Rohm and Haas) (Heas) Single bed configuration (9) Concentration chamber filled ion exchanger: Anion exchange resin (Rohm and Haas) Single bed configuration

<Operating conditions>
(1) Water to be treated: Water obtained by treating industrial water with a reverse osmosis membrane device (2) Conductivity of water to be treated: 6.2 μS / cm
(3) Specific resistance of water to be treated: 0.16 MΩ · cm
(4) Silica concentration in treated water: 719 μg / L
(5) Hardness in water to be treated: 0.4 mg CaCO ₃ / L
(6) Total carbonic acid concentration in treated water: 7.2 mg CO ₂ / L
(7) Flow rate of water to be treated: 0.3 m ³ / h
(8) Concentrated water flow rate: 0.1 m ³ / h
(9) Electrode water flow rate: 10 L / h
(10) Operating current value: 2.4A

(Example 2)
Deionized water was produced with EDI-1 in the same manner as in Example 1 except that the water to be treated was changed to the following operating conditions. Under the following operating conditions, after 2000 hours of continuous operation, the specific resistance, silica concentration, and average applied voltage of EDI-1 obtained were measured, and the results are shown in Table 1.
<Operating conditions>
(1) Water to be treated: Water obtained by treating industrial water with a reverse osmosis membrane device (2) Conductivity of water to be treated: 9.8 μS / cm
(3) Specific resistance of water to be treated: 0.10 MΩ · cm
(4) Silica concentration in treated water: 1021 μg / L
(5) Hardness in water to be treated: 0.7 mg CaCO ₃ / L
(6) Total carbonic acid concentration in treated water: 12.1 mg CO ₂ / L
(7) Flow rate of water to be treated: 0.3 m ³ / h
(8) Concentrated water flow rate: 0.1 m ³ / h
(9) Electrode water flow rate: 10 L / h
(10) Operating current value: 2.4A

(Comparative Example 1)
EDI-2 was produced in the same manner as in Example 1 except that the deionization module 20 was changed to the deionization module 120 shown in FIG. The deionization module 120 and the distribution method of the to-be-processed water in EDI-2 are demonstrated using FIG.
As shown in FIG. 5, the deionization module 120 includes a cation exchange membrane 122 disposed on one side of a frame body 124, and a cation exchange resin is filled in a hollowed portion of the frame body 124 so that a first small desalination chamber is formed. D1 ′ is formed, and an anion exchange membrane is disposed as an intermediate ion exchange membrane 126 on the other side of the frame 124. Further, a frame body 128 is disposed so as to sandwich the intermediate ion exchange membrane 126, and a hollow portion of the frame body 128 is filled with an anion exchange resin to form a second small desalting chamber D2 ′. An anion exchange membrane 130 is arranged on the other side of 128.
In addition, to-be-treated water inflow line A1 ′ and deionized water outflow line A2 ′ are connected to deionization module 120. The cation exchange membrane 122, the frame body 124, the intermediate ion exchange membrane 126, the frame body 128, and the anion exchange membrane 130 have communication holes 121a, 121b, 123a to 123c, 125a, 125b, 127a to which treated water flows. 127c, 129a, and 129b are provided. In addition, the frames 124 and 128 are provided with a flow path of water to be treated that communicates the communication holes 123a, 123b, 127b, and 127c with the desalted zone.

  The treated water flows from the treated water inflow line A1 'through the communication hole 121a, reaches the communication hole 123a, and flows into the first small desalination chamber D1' filled with the cation exchange resin. The treated water that has flowed into the first small desalting chamber D1 'flows while diffusing in the cation exchange resin, and reaches the communication hole 123b. During this time, the cation exchange resin in the water to be treated is mainly removed. Next, the water to be treated flows from the communication hole 123b through the communication holes 125a, 127a, and 129a, and then reaches the communication hole 129b via a pipe (not shown). Then, the water to be treated reaches the communication hole 127b from the communication hole 129b and flows into the second small desalination chamber D2 '. The treated water that has flowed into the second small desalting chamber D2 'flows while diffusing in the anion exchange resin and reaches the communication hole 127c. During this time, the anion component in the water to be treated is mainly removed. In this way, the cation component and the anion component are removed from the water to be treated, and it flows from the communication hole 127c through the communication holes 125b, 123c, 121b, and flows out from the deionized water outflow line A2 ′ as deionized water. .

The specifications of EDI-2 and the operating conditions are as follows. Under the following operating conditions, after 2000 hours of continuous operation, the specific resistance of the obtained deionized water, the silica concentration, and the average applied voltage of EDI-2 were measured, and the results are shown in Table 1.
<EDI-2 specification>
(1) Cation exchange membrane: Astom Co., Ltd. (2) Intermediate ion exchange membrane: Astom Co., Ltd. anion exchange membrane (3) Anion exchange membrane: Astom Co., Ltd. (4) First demineralized salt chamber thickness: 8 mm
(5) Second desalination chamber thickness: 12 mm
(6) Small desalination chamber dimensions: Width 200mm x Height 140mm
(7) Ion exchanger filled with the first small desalting chamber: Cation exchange resin (Rohm and Haas) single bed configuration (8) Ion exchanger filled with the second small desalting chamber: Anion exchange resin (Rohm and Haas) (Heas) Single bed configuration (9) Concentration chamber filled ion exchanger: Anion exchange resin (Rohm and Haas) Single bed configuration

<Operating conditions>
(1) Water to be treated: Water obtained by treating industrial water with a reverse osmosis membrane device (2) Conductivity of water to be treated: 6.2 μS / cm
(3) Specific resistance of water to be treated: 0.16 MΩ · cm
(4) Silica concentration in treated water: 719 μg / L
(5) Hardness in water to be treated: 0.4 mg CaCO ₃ / L
(6) Total carbonic acid concentration in treated water: 7.2 mg CO ₂ / L
(7) Flow rate of water to be treated: 0.3 m ³ / h
(8) Concentrated water flow rate: 0.1 m ³ / h
(9) Electrode water flow rate: 10 L / h
(10) Operating current value: 2.4A

(Comparative Example 2)
Deionized water was produced with EDI-2 in the same manner as in Comparative Example 1 except that the water to be treated was changed to the following operating conditions. Under the following operating conditions, after 2000 hours of continuous operation, the specific resistance of the obtained deionized water, the silica concentration, and the average applied voltage of EDI-2 were measured, and the results are shown in Table 1.
<Operating conditions>
(1) Water to be treated: Water obtained by treating industrial water with a reverse osmosis membrane device (2) Conductivity of water to be treated: 9.8 μS / cm
(3) Specific resistance of water to be treated: 0.10 MΩ · cm
(4) Silica concentration in treated water: 1021 μg / L
(5) Hardness in water to be treated: 0.7 mg CaCO ₃ / L
(6) Total carbonic acid concentration in treated water: 12.1 mg CO ₂ / L
(7) Flow rate of water to be treated: 0.3 m ³ / h
(8) Concentrated water flow rate: 0.1 m ³ / h
(9) Electrode water flow rate: 10 L / h
(10) Operating current value: 2.4A

As shown in Table 1, there was almost no difference in applied voltage between Example 1 and Comparative Example 1. However, in Example 1, deionized water with extremely high water quality having a specific resistance of 16.1 MΩ · cm and a silica concentration of 1.2 μg / L was obtained. On the other hand, in Comparative Example 1, deionized water having a low water quality with a specific resistance of 4.0 MΩ · cm and a silica concentration of 106 μg / L was obtained. From this, it was found that a large improvement in water quality can be realized by providing a desalting zone in the small desalting chamber and performing multi-stage treatment. When 2000 hours passed from the start of the production of deionized water, EDI-1 and EDI-2 were disassembled. As a result, generation of scale was not visually recognized in the concentration chamber.
In Example 2, water to be treated having higher silica concentration and total carbonic acid concentration than Example 1 was used, but a high water quality with a specific resistance of 14.4 MΩ · cm could be obtained. On the other hand, in Comparative Example 2 using the same liquid to be treated as in Example 2, the specific resistance of deionized water was 1.3 MΩ · cm and the silica concentration was 320 μgL, and the water quality was extremely low.

It is a schematic diagram of EDI concerning the embodiment of the present invention. It is a perspective view of the deionization module concerning the embodiment of the present invention. It is a schematic diagram of the deionization module concerning embodiment of this invention. It is a schematic diagram of the deionization module of EDI of 1 cell structure. It is a perspective view of the deionization module used for the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electric deionized water production apparatus 12 Cathode chamber 14 Cathode electrode 16 Anode chamber 18 Anode electrode 22, 122, 222 Cation exchange membrane 26, 126 Intermediate ion exchange membrane 30, 130, 230 Anion exchange membrane 34, 134, 234 Concentration chamber D, 224 Desalination chamber D1, D1 ′ First small desalination chamber D2, D2 ′ Second small desalination chamber D11 First small desalination chamber first desalination zone D12 First small desalination chamber second desalination zone D21 2nd small desalination chamber 1st desalination zone D22 2nd small desalination chamber 2nd desalination zone

Claims (10)

A space partitioned by the cation exchange membrane on one side and the anion exchange membrane on the other side is filled with an ion exchanger to provide a desalting chamber,
A concentration chamber is provided on both sides of the desalting chamber via the cation exchange membrane and the anion exchange membrane,
The demineralized chamber and the concentrating chamber are an electrical deionized water production apparatus disposed between an anode chamber having an anode electrode and a cathode chamber having a cathode electrode,
In the desalting chamber, a first small desalting chamber and a second small desalting chamber partitioned in the thickness direction of the desalting chamber by an intermediate ion exchange membrane disposed between the cation exchange membrane and the anion exchange membrane. A desalination chamber is formed,
In addition, the first small desalting chamber and the second small desalting chamber are formed with a multi-stage desalting zone parallel to the thickness direction of the desalting chamber. Type deionized water production equipment.   The electric system according to claim 1, wherein the intermediate ion exchange membrane is a single membrane of a cation exchange membrane or an anion exchange membrane, or a dual membrane in which both a cation exchange membrane and an anion exchange membrane are arranged. Deionized water production equipment.   The first small desalting chamber is filled with a cation exchanger in a single bed form, and the second small desalting chamber is filled with an anion exchanger in a single bed form. The electric deionized water production apparatus according to 1 or 2.   The electric deionized water production apparatus according to claim 3, wherein the thickness of the first small desalting chamber is smaller than the thickness of the second small desalting chamber.   5. The electricity according to claim 3, wherein the first small desalting chamber has a thickness of 4 to 16 mm, and the second small desalting chamber has a thickness of 8 to 22 mm. Type deionized water production equipment.   The first small desalting chamber is divided into two in parallel with the thickness direction of the desalting chamber to form a first small desalting chamber first desalting zone and a first small desalting chamber second desalting zone. The second small desalting chamber is divided into two in parallel with the thickness direction of the desalting chamber, so that a second small desalting chamber first desalting zone and a second small desalting chamber second desalting zone are formed. Water to be treated is a first small desalting chamber, a first desalting zone, a second small desalting chamber, a first desalting zone, a first small desalting chamber, a second desalting zone, and a second small desalting chamber. The electric deionized water production apparatus according to any one of claims 1 to 5, wherein the apparatus is controlled to flow in the order of two demineralized zones.   The electric deionized water production apparatus according to any one of claims 1 to 6, wherein the concentration chamber is filled with an anion exchanger in a single-bed form.   The cathode chamber and the anode chamber are filled with an ion exchanger in a single bed form of an anion exchanger or a cation exchanger, or in a mixed bed form of an anion exchanger and a cation exchanger, or separated from a cathode or an anode. The electric deionized water production according to any one of claims 1 to 7, wherein a laminate composed of an anion exchanger layer and a cation exchanger layer is arranged between the membrane and the membrane. apparatus.   The said cathode electrode and / or said anode electrode are divided | segmented for every corresponding desalination zone, The electric current applied to each electrode is controlled separately, The any one of Claims 1-8 characterized by the above-mentioned. The electric deionized water production apparatus as described.   A method for producing deionized water using the electric deionized water production apparatus according to claim 1, wherein treated water is circulated through a plurality of demineralized zones. Production method.

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