Ion separation equipment and condensate demineralization systems

Abstract

To provide a downsized ion separation device.SOLUTION: An ion separation device 1 has: an anode; a cathode; a first chamber H1 positioned between the anode and the cathode; a second chamber H2 positioned between the first chamber H1 and the cathode, neighboring and non-communicating with the first chamber H1; a first cation exchange membrane K1 partitioning the anode side of the first chamber H1; a first anion exchange membrane A1 partitioning the cathode side of the second chamber H2; and an intermediate ion exchange membrane M partitioning the first chamber H1 and the second chamber H2. The intermediate ion exchange membrane M is a cation exchange membrane or an anion exchange membrane; a chamber partitioned with the same kind of an ion exchange membrane among the first chamber H1 and the second chamber H2 constitutes a main chamber 2; and a chamber partitioned with a heterogeneous ion exchange membrane constitutes an auxiliary chamber 3. The main chamber 2 has a supply port 4 of a liquid involving a positive and negative ion component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to an ion separation apparatus and a condensate desalination system. [Background technology]

[0002] One known method for separating cations and anions from a liquid containing both is electrodialysis. Patent Document 1 discloses an electrodialysis apparatus having an ionization chamber for supplying an aqueous solution of NaCl, an acid chamber adjacent to the anode side of the ionization chamber via an anion exchange membrane, and an alkali chamber adjacent to the cathode side of the ionization chamber via a cation exchange membrane. Na ions move to the alkali chamber through the cation exchange membrane, and Cl ions move to the acid chamber through the anion exchange membrane, thereby separating the cations and anions. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 4065386 [Overview of the project] [Problems that the invention aims to solve]

[0004] The apparatus described in Patent Document 1 requires three chambers for separating cations and anions, making it difficult to miniaturize the apparatus.

[0005] The present invention aims to provide an ion separation device that is easily miniaturized. [Means for solving the problem]

[0006] The ion separation device of the present invention includes an anode, a cathode, a first chamber located between the anode and the cathode, a second chamber located between the first chamber and the cathode, adjacent to and non-communicating with the first chamber, a first cation exchange membrane partitioning the anode side of the first chamber, a first anion exchange membrane partitioning the cathode side of the second chamber, and an intermediate ion exchange membrane partitioning the first chamber and the second chamber. The intermediate ion exchange membrane is a cation exchange membrane or an anion exchange membrane. Among the first chamber and the second chamber, the chamber partitioned by the same type of ion exchange membrane constitutes the main chamber, and the chamber partitioned by different types of ion exchange membranes constitutes the auxiliary chamber. The main chamber has a supply port for a liquid containing positive and negative ion components.

Advantages of the Invention

[0007] According to the present invention, one of the positive and negative ion components moves to the auxiliary chamber, while the other remains in the main chamber. Therefore, it is possible to separate the positive and negative ion components in two chambers, and it is easy to miniaturize the ion separation device.

Brief Description of the Drawings

[0008] [Figure 1] It is a schematic diagram showing the first and second embodiments. [Figure 2] It is a schematic diagram showing a comparative example. [Figure 3] It is a schematic diagram showing the third embodiment. [Figure 4] It is a schematic diagram showing the fourth embodiment. [Figure 5] It is a schematic diagram showing the fifth embodiment. [Figure 6] It is a schematic diagram showing the sixth embodiment. [Figure 7] It is a schematic diagram showing the seventh embodiment. [Figure 8] It is a schematic diagram showing the eighth embodiment. [Figure 9] It is a schematic diagram of a rehydration desalination system.

Modes for Carrying Out the Invention

[0009] Hereinafter, some embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram for explaining the principle of the present invention, which shows the first and second embodiments in a simplified manner. FIG. 2 is a diagram similar to FIG. 1 that shows Comparative Examples 1 to 5 in a simplified manner. In FIGS. 1 and 2, the anode is shown as a figure with a + surrounded by a circle, and the cathode is shown as a figure with a - surrounded by a circle. Also, the positive ion component (cation component) is shown as a figure with a + surrounded by a square, and the negative ion component (anion component) is shown as a figure with a - surrounded by a square.

[0010] FIG. 1(a) shows the main chamber 2 and the auxiliary chamber 3 of the ion separation device 1 of the first embodiment. The ion separation device 1 has first and second chambers H1 and H2 located between the anode and the cathode. The second chamber H2 is located between the first chamber H1 and the cathode. The first chamber H1 is located on the anode side, and the second chamber H2 is located on the cathode side. That is, the anode side of the first chamber H1 is partitioned by the first cation exchange membrane K1, and the cathode side of the second chamber H2 is partitioned by the first anion exchange membrane A1. The first chamber H1 and the second chamber H2 are partitioned by the intermediate ion exchange membrane M and are adjacent to each other through the intermediate ion exchange membrane M. In this embodiment, the intermediate ion exchange membrane M is the second anion exchange membrane A2. Therefore, the first chamber H1 is partitioned by the first cation exchange membrane K1 on the anode chamber side and by the second anion exchange membrane A2 on the cathode side. The second chamber H2 is partitioned by the second anion exchange membrane A2 on the anode side and by the first anion exchange membrane A1 on the cathode side. The chamber partitioned by the two anion exchange membranes is called the main chamber 2, and the chamber partitioned by the cation exchange membrane and the anion exchange membrane on both sides is called the auxiliary chamber 3. In this embodiment, the second chamber H2 is the main chamber 2, and the first chamber H1 is the auxiliary chamber 3.

[0011] The main chamber 2 has a supply port 4 for a liquid containing positive and negative ionic components (hereinafter referred to as the liquid to be treated) and a discharge port 5 for the treated liquid. The liquid to be treated is supplied to the main chamber 2 through the supply port 4. The positive ionic components are electrically attracted to the cathode side but cannot pass through the first anion exchange membrane A1 and therefore remain in the main chamber 2. The negative ionic components (anionic components) are electrically attracted to the anode side and move to the sub-chamber 3 through the second anion exchange membrane A2. However, the negative ionic components cannot pass through the first cation exchange membrane K1 and therefore remain in the sub-chamber 3 after moving there. In this way, in this embodiment, the positive and negative ionic components can be separated into the main chamber 2 and the sub-chamber 3, respectively.

[0012] Figure 1(b) shows the main chamber 2 and sub-chamber 3 of the ion separation apparatus 1 of the second embodiment. In this embodiment, the intermediate ion exchange membrane M is the second cation exchange membrane K2. The first chamber H1 is partitioned on the anode side by the first cation exchange membrane K1 and on the cathode side by the second cation exchange membrane K2. The second chamber H2 is partitioned on the anode side by the second cation exchange membrane K2 and on the cathode side by the first anion exchange membrane A1. In this embodiment, the first chamber H1 is the main chamber 2, and the second chamber H2 is the sub-chamber 3. Positive ionic components are attracted to the cathode side by an electrical force and move to the sub-chamber 3 through the second cation exchange membrane K2. However, since positive ionic components cannot pass through the first anion exchange membrane A1, they remain in the sub-chamber 3 after moving there. The negative ion components are electrically attracted to the anode side, but they cannot pass through the first cation exchange membrane K1 and therefore remain in the main chamber 2. In this way, in this embodiment, the positive and negative ion components can be separated into the sub-chamber 3 and the main chamber 2, respectively.

[0013] Figure 2(a) shows the main chamber 2 and sub-chamber 3 of the ion separation apparatus 101 of Comparative Example 1. In this comparative example, the membrane configuration is the same as in the first embodiment, but the liquid to be treated is supplied to sub-chamber 3. Positive ion components are electrically attracted to the cathode side, but cannot pass through the second anion exchange membrane A2 and therefore remain in sub-chamber 3. Similarly, negative ion components are electrically attracted to the anode side, but cannot pass through the first cation exchange membrane K1 and therefore remain in sub-chamber 3. Therefore, in Comparative Example 1, positive and negative ion components cannot be separated. Figure 2(b) shows the main chamber 2 and sub-chamber 3 of the ion separation apparatus 101 of Comparative Example 2. In this comparative example, the membrane configuration is the same as in the second embodiment, but the liquid to be treated is supplied to sub-chamber 3. Positive ion components are electrically attracted to the cathode side, but cannot pass through the first anion exchange membrane A1 and therefore remain in sub-chamber 3. Similarly, the negative ionic components are electrically attracted to the anode side, but they cannot pass through the second cation exchange membrane K2 and remain in sub-chamber 3. Therefore, in Comparative Example 2, it is not possible to separate the positive and negative ionic components. Thus, when the liquid to be treated is supplied to sub-chamber 3, it is not possible to separate the positive and negative ionic components.

[0014] Figure 2(c) shows the main chamber 102 of the ion separator 101 of Comparative Example 3. In this comparative example, only the main chamber 102 is provided, and no sub-chamber is provided. Positive ionic components are electrically attracted to the cathode side and move to the cathode side through the first cation exchange membrane K1. Negative ionic components are electrically attracted to the anode side and move to the anode side through the first anion exchange membrane A1. This configuration is used, for example, when producing pure water, because both positive and negative ionic components are removed from the main chamber 102. However, chambers to receive positive and negative ionic components are needed on both sides of the main chamber 102, and at least three chambers are needed to separate the positive and negative ionic components. Figure 2(d) shows the main chamber 202 and sub-chamber 203 of the ion separator 101 of Comparative Example 4. In this comparative example, the main chamber 102 of Comparative Example 3 is divided into the main chamber 202 and the sub-chamber 203 by the second anion exchange membrane A2. The water to be treated is supplied to the main chamber 202, and the treated water in the main chamber 202 is then supplied to the sub-chamber 203. Negative ionic components are electrically attracted to the anode and move to the anode side through the first anion exchange membrane A1. Positive ionic components are electrically attracted to the cathode side, but cannot pass through the second anion exchange membrane A2, so they remain in the main chamber 202 and then move to the sub-chamber 203. The positive ionic components that have moved to the sub-chamber 203 are electrically attracted to the cathode side and move to the anode side through the first cation exchange membrane K1. This configuration is also used, for example, when producing pure water, because both positive and negative ionic components are removed from the main chamber 202 and the sub-chamber 203. However, chambers to accept positive and negative ionic components are required on both sides of the main chamber 202 and the sub-chamber 203, and at least four chambers are required to separate the positive and negative ionic components. The same result can be obtained by providing a cation exchange membrane instead of the second anion exchange membrane A2.

[0015] Figure 2(e) shows the main chamber 2 and sub-chamber 3 of the ion separation apparatus 101 of Comparative Example 5. In this comparative example, the membrane configuration is the same as in the first embodiment, but the main chamber 2 and sub-chamber 3 are connected in series by a connecting tube 6. Positive ion components are electrically attracted to the cathode side, but they cannot pass through the first anion exchange membrane A1 and remain in the main chamber 2. Negative ion components (anion components), as in the first embodiment, move to the sub-chamber 3 through the second anion exchange membrane A2 and remain in the sub-chamber 3. However, the positive ion components that remain in the main chamber 2 move to the sub-chamber 3 through the connecting tube 6. Therefore, when the main chamber 2 and sub-chamber 3 are connected, it is not possible to separate positive and negative ion components.

[0016] In this embodiment, the intermediate ion exchange membrane M is either a cation exchange membrane or an anion exchange membrane. Of the first chamber H1 and the second chamber H2, the chamber separated by the same type of ion exchange membrane (both anion exchange membranes, or both cation exchange membranes) constitutes the main chamber 2, and the chamber separated by different types of ion exchange membranes (one an anion exchange membrane and the other a cation exchange membrane) constitutes the sub-chamber 3. The liquid to be treated, containing positive and negative ionic components, is supplied to the main chamber 2. The main chamber 2 and the sub-chamber 3 are not connected. Not being connected means that ions are allowed to pass through the intermediate ion exchange membrane M, but liquid is not allowed to flow between the main chamber 2 and the sub-chamber 3. In other words, the main chamber 2 and the sub-chamber 3 are not connected by a connecting pipe 6. With this configuration, positive and negative ions can be separated in the two chambers.

[0017] In the case where the main chamber 2 is the second chamber H2 (first embodiment), it is preferable that the main chamber 2 and the sub-chamber 3 are filled with an anion exchanger A, such as an anion exchange resin. Anion exchanger A facilitates the movement of negative ion components (anion components) to the sub-chamber 3. In the case where the main chamber 2 is the first chamber H1 (second embodiment), it is preferable that the main chamber 2 and the sub-chamber 3 are filled with a cation exchanger K, such as a cation exchange resin. Cation exchanger K facilitates the movement of positive ion components (cation components) to the sub-chamber 3.

[0018] The present invention will be described in further detail below with reference to other embodiments. Descriptions common to the first and second embodiments will be omitted. Figure 3 is a schematic diagram showing a third embodiment of the present invention, and the membrane configuration corresponds to the first embodiment. An anode chamber 11 equipped with an anode E1 is located on the anode side of the first chamber H1 (sub-chamber 3). A cathode chamber 12 equipped with a cathode E2 is located on the cathode side of the second chamber H2 (main chamber 2). Electrode water is supplied to the anode chamber 11 and the cathode chamber 12. The electrode water is water, preferably pure water. The anode chamber 11 and the cathode chamber 12 may be connected in parallel or in series. Cationic resin regeneration waste liquid is supplied to the second chamber H2. Cationic resin regeneration waste liquid is waste liquid discharged from the cation resin regeneration device of a condensate demineralizer that processes condensate containing ammonia.

[0019] This point will be explained in detail below with reference to Figure 9. In thermal power plants and pressurized water reactors, high-temperature, high-pressure steam generated in a boiler is supplied to a steam turbine, and the exhaust steam discharged from the steam turbine is condensed in a condenser to become condensate, which is then supplied to the boiler as feedwater in a water cycle. Since impurities such as corrosion products accumulate in the condensate, thermal power plants and pressurized water reactors are equipped with a condensate demineralizer 51 to remove these impurities from the condensate during steady-state operation. If the condenser is cooled by seawater, the condensate demineralizer 51 also has the function of protecting the condensate system by capturing sodium chloride and other substances contained in seawater that may be mixed into the condensate for a certain period of time. The condensate demineralizer 51 is filled with anionic resin and cationic resin. The anionic resin is regenerated in an anionic resin regeneration unit 52, and the cationic resin is regenerated in a cationic resin regeneration unit 53, and these are reused in the condensate demineralizer 51.

[0020] On the other hand, in thermal power plants and pressurized water reactors, pH adjusters such as ammonia are added to the condensate to make it alkaline in order to suppress corrosion of condensate system piping, etc. Therefore, when there is no seawater contamination, the ion load of the condensate desalination unit 51 is almost entirely ammonia. However, in preparation for seawater contamination, when the cation exchange resin captures about 50-70% of the ion exchange capacity of ammonia, the cation resin regeneration unit 53 uses hydrochloric acid, sulfuric acid, etc. (the following explanation will use hydrochloric acid (HCl aq) as a representative) to regenerate ammonium ions (NH4 + The chemical regeneration process removes the ammonium ions (NH4) and converts the exchange group to the H type. The regeneration waste liquid mainly consists of hydrochloric acid, which is the regenerating agent, and ion-exchanged ammonium ions (NH4). + ) and HCl are included. The regeneration waste liquid may contain impurities present in the condensate system (Na, Fe, Cu, etc.) and carbonate ions introduced during resin transfer and air mixing, but these are all in very small amounts. Therefore, the regeneration waste liquid of the cation exchange resin discharged from the cation resin regeneration device 53 is essentially NH4Cl + HCl.

[0021] Conventionally, the ammonia component contained in the regeneration wastewater has not been recovered. The regeneration wastewater is mixed with the regeneration wastewater of caustic soda used in the regeneration of anion exchange resin, neutralized, and then discarded. However, in order to maintain a constant pH of the condensate, an amount of ammonia is added to the condensate system to replenish the amount removed by the condensate demineralizer 51. For this reason, it is desirable to recycle the ammonia, but in order to do so, it is necessary to separate the Cl- ions contained in the regeneration wastewater from the ammonia. Accordingly, the cation resin regeneration wastewater discharged from the cation resin regeneration unit 53 is treated by the ion separator 1 connected to the cation resin regeneration unit 53. The condensate demineralizer 51, the anion resin regeneration unit 52, the cation resin regeneration unit 53, and the ion separator 1 constitute the condensate demineralizer system 50.

[0022] In this embodiment, the second chamber H2 (main chamber 2) has a supply port 4 for NH4Cl + HCl, and the first chamber H1 (sub-chamber 3) has a supply port 7 for water. NH4Cl + HCl is supplied to the second chamber H2 (main chamber 2), and water is supplied to the first chamber H1 (sub-chamber 3). The Cl - ions in the main chamber 2 move through the second anion exchange membrane A2 to the sub-chamber 3. In the cathode chamber 12, electrolysis of water causes the chemical reaction of 2H2O + 2e - →H2 + 2OH - to occur, and hydroxide ions (OH - ) are continuously generated. The hydroxide ions move through the first anion exchange membrane A1 to the main chamber 2, and a part of them combines with the dissociated protons (H + ) in hydrochloric acid to form water. Ammonium ions (NH4 + ) combine with a part of the hydroxide ions to form ammonia, which dissolves in water. As a result, an aqueous ammonia solution (NH3aq) is generated in the main chamber 2. In the anode chamber <0000 or 11, the electrolysis of water causes the chemical reaction of 2H2O → O2 + 4H + + 4e - to occur, and protons are continuously generated. The protons move through the first cation exchange membrane K1 to the sub-chamber 3. The Cl - ions that have moved to the sub-chamber 3 combine with the protons that have also moved to the sub-chamber 3 to form HCl, which dissolves in the water supplied to the sub-chamber 3. As a result, hydrochloric acid (HCl aq) is generated in the sub-chamber 3. To enhance the migration efficiency of protons, it is preferable to fill the anode chamber 11 with a cation exchange resin. To enhance the migration efficiency of hydroxide ions and Cl - ions, it is preferable to fill the main chamber 2, the sub-chamber 3, and the cathode chamber 12 with an anion exchange resin.

[0023] Since the amount of Cl is determined by the amount of regenerated waste liquid supplied to the main chamber 2, the Cl concentration of hydrochloric acid can be controlled by adjusting the flow rate of water supplied to the sub-chamber 3. The Cl concentration of the regenerated waste liquid is about 3.5%, but the Cl concentration of hydrochloric acid can be adjusted, for example, within the range of 3.5 to 35%. By making the flow rate of water supplied to the sub-chamber 3 less than the flow rate of regenerated waste liquid supplied to the main chamber 2, hydrochloric acid with a higher Cl concentration than the regenerated waste liquid can be produced. Since the flow rate of water supplied to the sub-chamber 3 can be set independently of the flow rate of regenerated waste liquid supplied to the main chamber 2, the Cl concentration of hydrochloric acid can be freely adjusted. From the viewpoint of chemical resistance and fuming, it is preferable to keep the Cl concentration of hydrochloric acid at 25% or less.

[0024] Unless there is seawater leakage, the ion load of the anion exchange resin will be reduced by the regenerating agent (Cl) of the cation resin remaining in the condensate. - SO4 2- These include ions and carbonate ions, but all are present in trace amounts. Therefore, the frequency of chemical regeneration of the anion exchange resin can be kept low. However, since a neutralizing agent (NaOH) is required for the regeneration waste liquid of the cationic resin, chemical regeneration is performed on the anion exchange resin each time. In this embodiment, since the regeneration waste liquid of the cationic resin can be recovered, a neutralizing agent is unnecessary. Therefore, it is possible to reduce the frequency of anion exchange resin regeneration.

[0025] Figure 4 is a schematic diagram showing a fourth embodiment of the present invention, and the membrane configuration corresponds to that of the first embodiment. The ion separation apparatus 1 of this embodiment has a plurality of adjacent units. In this embodiment, two units (hereinafter referred to as the first unit U1 and the second unit U2) are provided. Each unit has first and second chambers H1 and H2, a first cation exchange membrane K1, a first anion exchange membrane A1, and an intermediate ion exchange membrane M. The first anion exchange membrane A1 of one unit (second unit U2) located on the anode E1 side and the first cation exchange membrane K1 of the other unit (first unit U1) located on the cathode E2 side are adjacent. For this reason, the first unit U1 is adjacent to the cathode chamber 12 equipped with cathode E2 on the cathode E2 side of the second chamber H2 (main chamber 2), but is not adjacent to the anode chamber 11. Furthermore, the second unit U2 is adjacent to the anode chamber 11, which contains anode E1, on the anode E1 side of the first chamber H1 (sub-chamber 3), but is not adjacent to the cathode chamber 12. The intermediate ion exchange membrane M of the first unit U1 and the intermediate ion exchange membrane M of the second unit U2 are of the same type, and in this embodiment, they are the second anion exchange membrane A2. The main chamber 2 of the first unit U1 and the main chamber 2 of the second unit U2 are connected in parallel. That is, although not shown in the figures, the main chambers 2 of the first and second units U1 and U2 are supplied with a cation resin regeneration waste liquid mainly composed of NH4Cl + HCl from a common pipe, and the sub-chambers 3 of the first and second units U1 and U2 are supplied with water from a common pipe. Water (electrode water) is supplied to the anode chamber 11 and the cathode chamber 12. The anode chamber 11 and the cathode chamber 12 may be connected in parallel or in series.

[0026] The first anion exchange membrane A1 of the second unit U2 and the first cation exchange membrane K1 of the first unit U1 form a bipolar membrane BP. The bipolar membrane BP is an ion exchange membrane formed by bonding an anion exchange membrane and a cation exchange membrane. Water that has penetrated into the membrane dissociates at the interface between the anion exchange membrane and the cation exchange membrane, generating protons and hydroxide ions. The bipolar membrane BP prevents the permeation of ionic components, but the generated protons and hydroxide ions allow current to flow. In this embodiment, taking advantage of these properties of the bipolar membrane BP, the bipolar membrane BP is used as a means of supplying protons and hydroxide ions, i.e., as a substitute for the anode E1 and cathode E2. Therefore, the first unit U1 has the same configuration as the ion separation apparatus 1 of the third embodiment, except that the anode chamber 11 is replaced with the bipolar membrane BP, and operates on the same principle as the ion separation apparatus 1 of the third embodiment. Similarly, the second unit U2 has the same configuration as the ion separator 1 of the third embodiment, except that the cathode chamber 12 is replaced with a bipolar membrane BP, and operates on the same principle as the ion separator 1 of the third embodiment.

[0027] In this embodiment, multiple units U1 and U2 are connected in parallel, making it easy to increase the flow rate (processing volume) of the liquid to be processed. The number of units is not limited. Although not shown in the diagram, when three or more units are connected in parallel, the units other than those at both ends are separated from the adjacent units on either side by a bipolar membrane BP.

[0028] Figure 5 is a schematic diagram showing a fifth embodiment of the present invention. In this embodiment, the main chamber 2 of one unit (first unit U1) is on the upstream side, and the main chamber 2 of the other unit (second unit U2) is on the downstream side, and these main chambers 2 are connected in series by a connecting pipe 6. The first unit U1 is located on the cathode E2 side, and the second unit U2 is located on the anode E1 side. The membrane configuration of the first unit U1 corresponds to the first embodiment, and the membrane configuration of the second unit U2 corresponds to the second embodiment. That is, the intermediate ion exchange membrane M of the first unit U1 and the intermediate ion exchange membrane M of the second unit U2 are different types of ion exchange membranes. It is preferable that the main chamber 2, sub-chamber 3 and cathode chamber 12 of the first unit U1 are filled with anion exchange resin, and it is preferable that the main chamber 2, sub-chamber 3 and anode chamber 11 of the second unit U2 are filled with cation exchange resin.

[0029] The waste liquid from the regeneration of the cationic resin, mainly composed of NH4Cl + HCl, is supplied to the main chamber 2 of the first unit U1. In the same principle as in the first and third embodiments, an aqueous ammonia solution (NH3aq) is discharged from the main chamber 2 of the first unit U1. Water is also supplied to the sub-chamber 3 of the first unit U1, and hydrochloric acid (HClaq) is discharged. The aqueous ammonia solution discharged from the main chamber 2 of the first unit U1 is supplied to the main chamber 2 of the second unit U2, and water is supplied to the sub-chamber 3 of the second unit U2. Ammonium ions (NH4Cl + HCl) dissociated from the aqueous ammonia solution are then discharged. + The hydroxide ions move through the second cation exchange membrane K2 to the sub-chamber 3 of the second unit U2, where they combine with hydroxide ions supplied from the bipolar membrane BP to form ammonia (NH4·OH). As a result, an aqueous ammonia solution is produced in the sub-chamber 3 of the second unit U2. The hydroxide ions dissociated from the aqueous ammonia solution in the main chamber 2 of the second unit U2 combine with protons supplied from the anode E1 to form water. As a result, water (H2O) is produced in the main chamber 2 of the second unit U2.

[0030] In this embodiment, as in the third and fourth embodiments, the hydrochloric acid concentration can be freely adjusted by adjusting the flow rate of water supplied to the sub-chamber 3 of the first unit U1. Furthermore, the concentration of ammonium ions in the ammonia aqueous solution can be freely adjusted by adjusting the flow rate of water supplied to the sub-chamber 3 of the second unit U2. This is because the amount of ammonium ions depends on the amount of ammonium ions contained in the cation resin regeneration waste liquid supplied to the main chamber 2 of the second unit U2, i.e., the amount of liquid to be treated, whereas the amount of water depends on the flow rate of water supplied to the sub-chamber 3 of the second unit U1.

[0031] Furthermore, in this embodiment, it is possible to recover more water than is supplied. The flow rate of water discharged from the main chamber 2 of the second unit U2 depends on the flow rate of the ammonia aqueous solution discharged from the main chamber 2 of the first unit U1, and the flow rate of the ammonia aqueous solution depends on the flow rate R1 of the cation resin regeneration waste liquid supplied to the main chamber 2 of the first unit U1. In contrast, the flow rate R2 of water supplied to the sub-chamber 3 of the first unit U1 and the flow rate R3 of water supplied to the sub-chamber 3 of the second unit U2 can be freely adjusted. Furthermore, the flow rate R4 of the electrode water supplied to the anode chamber 11 and the flow rate R5 of the electrode water supplied to the cathode chamber 12 can also be freely adjusted, so by adjusting the flow rates so that R1 > R2 + R3 + R4 + R5, water recovery becomes possible. When electrode water is passed in series between the anode chamber 11 and the cathode chamber 12, the flow rate R4 of the electrode water supplied to the anode chamber 11 (or the flow rate R5 of the electrode water supplied to the cathode chamber 12) can be freely adjusted. By adjusting the flow rate so that R1 > R2 + R3 + R4 (R5), water recovery becomes possible.

[0032] Figure 6 is a schematic diagram showing a sixth embodiment of the present invention. In this embodiment, the ion separator 1 of the fifth embodiment is connected in parallel in the same manner as in the fourth embodiment. The ion separator 1 has a plurality of integrated units T1 and T2, and each integrated unit has one unit (second unit U1) and the other unit (first unit U2) in the fifth embodiment. The first unit U1 and the second unit U2 are connected in series. The main chamber 2 (21) on the upstream side of one integrated unit (first integrated unit T1) and the main chamber 2 (22) on the upstream side of the other integrated unit (second integrated unit T2) are connected in parallel. The main chamber 2 (23) on the downstream side of the first integrated unit T1 and the main chamber 2 (24) on the downstream side of the second integrated unit T2 are connected in parallel. Water is supplied to the sub-chambers 3 of each unit from a common pipe. Each integrated unit T1 and T2 operates in the same manner as in the fifth embodiment. In this embodiment, as in the fourth embodiment, the flow rate of the liquid to be treated can be easily increased. The number of integrated units is not limited. Although not shown in the diagram, when three or more integrated units are connected in parallel, the integrated units other than those at the ends are separated from the adjacent integrated units on either side by bipolar membranes (BP).

[0033] Figure 7 is a schematic diagram showing a seventh embodiment of the present invention, and the membrane configuration corresponds to that of the second embodiment. An anode chamber 11 equipped with an anode E1 is located on the anode E1 side of the first chamber H1 (main chamber 2). A cathode chamber 12 equipped with a cathode E2 is located on the cathode E2 side of the second chamber H2 (sub-chamber 3). An aqueous ammonia solution (NH3aq) is supplied to the first chamber H1, and water is supplied to the second chamber H2 (sub-chamber 3). The aqueous ammonia solution is not particularly limited, but may be discharged from the ion separation apparatus 1 of the third to sixth embodiments. Water is supplied to the second chamber H2.

[0034] Ammonium ions (NH4) dissociated from an aqueous ammonia solution + ) moves to sub-chamber 3 through the second cation exchange membrane K2. In the cathode chamber 12, 2H2O + 2e is produced by the electrolysis of water. - →H2+2OH - A chemical reaction occurs, resulting in hydroxide ions (OH)- ) are continuously generated. The hydroxide ions move to sub-chamber 3 through the first anion exchange membrane A1. Ammonium ions (NH4 + ) combines with hydroxide ions to form ammonia, which dissolves in water. As a result, an aqueous ammonia solution (NH3aq) is generated in sub-chamber 3. In anode chamber 11, the electrolysis of water results in 2H2O → O2 + 4H + +4e - A chemical reaction occurs, and protons (H + ) is continuously generated. Hydroxide ions dissociated from the ammonia aqueous solution (NH3aq) combine with protons supplied from the anode E1 to form water. This water can be reused as water supplied to the main chamber 2. To improve the transport efficiency of protons and ammonium ions, it is preferable to fill the anode chamber 11, the main chamber 2, and the sub-chamber 3 with cation exchange resin, and to improve the transport efficiency of hydroxide ions, it is preferable to fill the cathode chamber 12 with anion exchange resin.

[0035] In this embodiment, the concentration of ammonium ions in the ammonia aqueous solution can be adjusted. The amount of ammonium ions in sub-chamber 3 depends on the flow rate of the ammonia aqueous solution supplied to the main chamber 2. In contrast, the flow rate of water supplied to sub-chamber 3 can be freely adjusted. Therefore, by reducing the flow rate of water supplied to sub-chamber 3 compared to the flow rate of the ammonia aqueous solution supplied to the main chamber 2, the concentration of ammonium ions can be increased. In other words, concentration of the ammonia aqueous solution becomes possible. Furthermore, since more water is recovered from the main chamber 2 than is supplied to sub-chamber 3, water recovery is also possible.

[0036] Ammonia can be used, for example, in flue gas denitrification systems at thermal power plants. Flue gas denitrification systems remove nitrogen oxides (NOx) contained in exhaust gas, and the ammonia catalytic reduction method is particularly widely used. Specifically, ammonia is injected into the exhaust gas and passed through a catalyst at high temperature, causing the nitrogen oxides to decompose into nitrogen and water vapor. Ammonia can also be used as a fuel. Technologies for burning ammonia alone or in combination with LNG are already in practical use. Because ammonia contains a lot of hydrogen, it can also be used as a hydrogen carrier. Hydrogen can be extracted by the decomposition (dehydrogenation) reaction of ammonia and used in fuel cells. In these applications, increasing the concentration of the ammonia aqueous solution is effective from the viewpoint of transport efficiency and storability.

[0037] Ammonia is sometimes used to clean wafers. To prevent wafers from becoming charged and attracting particles, water with ammonia added at a certain concentration (approximately 0.6 to 23 mg / L) is sometimes used as a cleaning solution. The cleaning water contains only trace amounts of ions other than ammonia, and almost no anions. For water quality monitoring, a portion of the cleaning water is taken out into an electrical conductivity measurement cell and its electrical conductivity is measured. The cleaning water introduced into the electrical conductivity measurement cell is discarded after measurement. By treating the cleaning water with the ion separation device 1 of this embodiment, an ammonia aqueous solution with a high ammonia concentration can be generated and reused. The water can also be reused as cleaning water.

[0038] Figure 8 is a schematic diagram showing an eighth embodiment of the present invention, and the membrane configuration corresponds to that of the second embodiment. The ion separation apparatus 1 of this embodiment has a plurality of adjacent units, similar to the fourth embodiment. In this embodiment, two units (hereinafter referred to as the first unit U1 and the second unit U2) are provided. Each unit has first and second chambers H1 and H2, a first cation exchange membrane K1, a first anion exchange membrane A1, and a second cation exchange membrane K2 (intermediate ion exchange membrane M). The first anion exchange membrane A1 of one unit (second unit U2) and the first cation exchange membrane K1 of the other unit (first unit U1) are adjacent. Therefore, the first unit U1 is adjacent to the cathode chamber 12 equipped with cathode E2 on the cathode E2 side of the second chamber H2 (sub-chamber 3), but is not adjacent to the anode chamber 11. The second unit U2 is adjacent to the anode chamber 11, which contains anode E1, on the anode E1 side of the first chamber H1 (main chamber 2), but is not adjacent to the cathode chamber 12. The main chambers 2 of the first and second units U1 and U2 are supplied with ammonia aqueous solution from a common pipe, and the sub-chambers 3 of the first and second units U1 and U2 are supplied with water from a common pipe. Electrode water is also supplied to the anode chamber 11 and the cathode chamber 12 from a common pipe.

[0039] In this embodiment, multiple units U1 and U2 are connected in parallel, improving current efficiency and easily increasing the flow rate (processing volume) of the liquid to be processed. The number of units is not limited. Although not shown in the diagram, when three or more units are connected in parallel, the units other than those at both ends are separated from the adjacent units on either side by a bipolar membrane BP.

[0040] (Example 1) In the third embodiment, while a current of 3A was applied to the ion separator 1, a mixture of NH4Cl and HCl with an ammonia concentration of 1% and a Cl concentration of 3.5% was supplied to the main chamber 2 at a flow rate of 0.1 L / h. 5 cm × 4 cm electrodes were used as the anode E1 and cathode E2. Pure water was supplied to the sub-chamber 3 at a flow rate of 0.02 L / h, and pure water was passed through the anode chamber 11 and cathode chamber 12 at a flow rate of 0.01 L / h. Anion exchange resin was packed into the main chamber 2, sub-chamber 3, and cathode chamber 12, and cation exchange resin was packed into the anode chamber 11. Cl was supplied from the main chamber 2. - A 1% ammonia solution containing almost no ions (<1 mg Cl / L) was obtained, and hydrochloric acid with a Cl concentration of 17.5% was obtained from sub-chamber 3.

[0041] (Example 2) While a current of 3A was supplied to the ion separator 1 of the fifth embodiment, a mixture of NH4Cl and HCl with an ammonia concentration of 1% and a Cl concentration of 3.5% was supplied to the main chamber 2 of the first unit U1 at a flow rate of 0.1 L / h. From the main chamber 2 of the first unit U1, Cl - An ammonia solution with a concentration of 1% and containing almost no ions (<1 mgCl / L) was obtained. This ammonia solution was supplied to the main chamber 2 of the second unit U2. Pure water without ammonia was obtained from the main chamber 2 of the second unit U2. A portion of this pure water was supplied to the sub-chamber 3 of the first unit U1 at a flow rate of 0.02 L / h, and to the sub-chamber 3 of the second unit U2 at a flow rate of 0.02 L / h. Pure water was also passed through the anode chamber 11 and the cathode chamber 12 at a flow rate of 0.01 L / h. 5 cm × 4 cm electrodes were used as the anode E1 and cathode E2. Anion exchange resin was packed into the main chamber 2, sub-chamber 3 and cathode chamber 12 of the first unit U1, and cation exchange resin was packed into the main chamber 2, sub-chamber 3 and anode chamber 11 of the second unit U2. Hydrochloric acid with a Cl concentration of 17.5% was obtained from sub-chamber 3 of the first unit U1, and an ammonia solution with a 5% ammonia concentration was obtained from sub-chamber 3 of the second unit U2. In addition, 0.05 L / h of pure water was obtained.

[0042] (Example 3) While a current of 3A was applied to the ion separator 1 of the seventh embodiment, a 1% ammonia solution was supplied to the main chamber 2 at a flow rate of 0.1 L / h. Pure water was supplied to the sub-chamber 3 at a flow rate of 0.02 L / h. Cation exchange resin was packed into the main chamber 2, sub-chamber 3, and anode chamber 11, and anion exchange resin was packed into the cathode chamber 12. Pure water without ammonia was obtained from the main chamber 2. A portion of this pure water was passed in series through the anode chamber 11 and cathode chamber 12 at a flow rate of 0.01 L / h. A 5% ammonia solution and 0.07 L / h of pure water were obtained from the sub-chamber 3. [Explanation of symbols]

[0043] 1. Ion separation device 2 Main room 3 Antechamber 50 Condensate Desalination System 51 Condensate demineralizer 52 Anionic resin regeneration device 53 Cationic resin regeneration device E1 anode E2 cathode A1 First anion exchange membrane A2 Second anion exchange membrane BP bipolar membrane H1 Room 1 H2, Room 2 K1 First cation exchange membrane K2 Second cation exchange membrane M Intermediate ion exchange membrane U1, U2 Units T1, T2 Integrated Unit

Claims

1. an anode, a cathode, a first chamber located between the anode and the cathode, a second chamber located between the first chamber and the cathode and adjacent to but not communicating with the first chamber, a first cation exchange membrane separating the anode side of the first chamber, a first anion exchange membrane separating the cathode side of the second chamber, and an intermediate ion exchange membrane separating the first chamber and the second chamber; an ion separation device, wherein the intermediate ion exchange membrane is a cation exchange membrane or an anion exchange membrane, and the chamber separated by the same type of ion exchange membrane of the first chamber and the second chamber constitutes a main chamber, and the chamber separated by a different type of ion exchange membrane constitutes an auxiliary chamber, and the main chamber has a supply port for a liquid containing positive and negative ion components.

2. 2. The ion separation device according to claim 1, wherein the main chamber is the second chamber when the intermediate ion exchange membrane is a second anion exchange membrane, and the main chamber is the first chamber when the intermediate ion exchange membrane is a second cation exchange membrane.

3. 3. The ion separation device according to claim 2, wherein when the intermediate ion exchange membrane is the second anion exchange membrane, the main chamber and the auxiliary chamber are filled with an anion exchanger, and when the intermediate ion exchange membrane is the second cation exchange membrane, the main chamber and the auxiliary chamber are filled with a cation exchanger.

4. The ion separator according to claim 1 , wherein the auxiliary chamber has a water supply port.

5. 5. The ion separator according to claim 4, wherein the flow rate of the water supplied to the auxiliary chamber is less than the flow rate of the liquid supplied to the main chamber.

6. a plurality of units each having the first and second chambers, the first cation exchange membrane, the first anion exchange membrane, and the intermediate ion exchange membrane; the plurality of units include one unit and another unit adjacent to the one unit on the cathode side of the one unit, and the one unit and the other unit are connected such that a main chamber of the other unit is on the upstream side and a main chamber of the one unit is on the downstream side; The ion separation device according to claim 1 , wherein the first anion exchange membrane of the one unit and the first cation exchange membrane of the other unit are adjacent to each other.

7. 7. The ion separation device according to claim 6, wherein the first anion exchange membrane of the one unit and the first cation exchange membrane of the other unit form a bipolar membrane.

8. The ion separation device according to claim 7, wherein a plurality of integrated units are provided, each of which has one unit adjacent to the other unit, and the main chambers on the upstream side of each integrated unit are connected in parallel, and the main chambers on the downstream side of each integrated unit are connected in parallel.

9. a condensate demineralizer filled with at least a cation resin and treating condensate containing ammonia; a cationic resin regeneration device for regenerating the cationic resin; The ion separation device according to any one of claims 1 to 8, wherein ammonia is recovered by treating a cation exchange resin regeneration waste liquid discharged from the cation exchange resin regeneration device; A condensate desalination system having:

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