JP2019188367A - Method for producing electric deionized water production apparatus - Google Patents

Abstract

To provide a method for producing an electric deionized water production apparatus capable of further reducing a rise time of treated water quality.SOLUTION: There is provided a method for producing an electric deionized water production apparatus 4, including: opposing cathode 12 and anode 11; a desalination chamber D defined by ion exchange membranes a1 and c1 between the cathode and the anode, and filled with granular ion exchangers AE and CE, the method including: charging the granular ion exchangers into the desalination chamber defined by the ion exchange membranes; and applying a hydrothermal treatment thereto so that the ion exchanger charged in the desalination chamber and the ion exchange membranes are brought into contact with hot water of 80°C or higher and lower than a boiling point for 5 hours or longer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an electrical deionized water production apparatus.

  In semiconductor and liquid crystal manufacturing processes, semiconductor wafers and glass substrates are cleaned using ultrapure water from which impurities are highly removed. An electrical deionized water production apparatus (EDI) is used as an ultrapure water production apparatus used for such cleaning.

  EDI, which has been put into practical use, is basically desalted by filling the gap formed by the cation exchange membrane and the anion exchange membrane with an ion exchange resin such as anion exchange resin or cation exchange resin as an ion exchanger. It is set as a chamber and water to be treated is passed through the ion exchange resin layer. In the EDI, a direct current is applied in a direction perpendicular to the flow of water to be treated through both a cation exchange membrane and an anion exchange membrane, thereby flowing through a concentration chamber formed outside the desalting chamber. Deionized water (treated water) is produced by electrically moving ions in the treated water into the concentrated water.

  The specific resistance value indicating the quality of the treated water treated with EDI is generally increased slowly for several hours to several tens of hours after the first treatment of the treated water, and then reaches the maximum value. It is known that a steady value is reached. In particular, when a salt ion exchange resin is used, the time becomes longer.

  After EDI production, in order to shorten the rise time of the treated water quality in the first deionized water production process (time until the specific resistance value of the treated water reaches a steady value), the resin is removed in a wet and regenerated form. Patent Document 1 discloses a method for filling a salt chamber. Patent Document 1 describes that by filling the desalting chamber with a resin in a wet state and in a regenerated form, leakage of the organic substance component (TOC) derived from the ion exchanger can be suppressed and the rising of the treated water quality can be improved. Has been.

Japanese Patent Laid-Open No. 2006-129863

  In the filling method described in Patent Document 1, the rising time of the treated water quality can be made shorter than that of the prior art, but there is still room for improvement because it requires a certain amount of water passing time.

  In view of the above problems, an object of the present invention is to provide a method for producing an electrical deionized water production apparatus that can further reduce the rise time of the quality of treated water.

One form of the manufacturing method of the electrical deionized water manufacturing apparatus according to the present invention is
A method for producing an electrical deionized water production apparatus, comprising: a cathode and an anode facing each other; and a demineralization chamber filled with a granular ion exchanger defined by an ion exchange membrane between the cathode and the anode. Because
A filling step of filling a granular ion exchanger into a desalting chamber defined by an ion exchange membrane;
A hydrothermal treatment step of bringing the ion exchanger filled in the desalting chamber and the ion exchange membrane into contact with hot water having a boiling point of 80 ° C. or higher and lower than the boiling point for 5 hours or more;
including.

Another embodiment of the method for producing an electric deionized water production apparatus according to the present invention is as follows:
A method for producing an electrical deionized water production apparatus, comprising: a cathode and an anode facing each other; and a demineralization chamber filled with a granular ion exchanger defined by an ion exchange membrane between the cathode and the anode. Because
A hydrothermal treatment process in which each of the granular ion exchanger and the ion exchange membrane is brought into contact with hot water of 80 ° C. or higher and lower than the boiling point for 5 hours or more
A filling step of filling the hot water treated ion exchanger into a desalting chamber defined by the hot water treated ion exchange membrane;
including.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrical deionized water manufacturing apparatus which can further reduce the rise time of treated water quality can be provided.

It is a schematic structural example of the pure water manufacturing apparatus containing EDI manufactured by one Embodiment of this invention. (A) is a schematic block diagram of the hot water treatment test apparatus in the Example of this invention, (b) is a detailed block diagram of the desalination chamber of the test stack. It is a hot-water treatment cycle in the Example of this invention. It is a graph which shows a time-dependent change of the specific resistance value of the treated water in the Example and comparative example of this invention. It is a graph which shows the relationship of the hot water processing time and the steady specific resistance value (specific resistance value when it becomes a fixed value) of treated water in the Example and comparative example of this invention. It is a flowchart of the manufacturing method of EDI which is one Embodiment of this invention. It is a flowchart of the manufacturing method of EDI which is other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The model of the electric deionized water production apparatus (hereinafter also referred to as “EDI”) produced by the production method according to the present embodiment is not particularly limited, but here, the EDI shown in FIG. 1 is taken as an example. To do.

(Embodiment 1)
Fig.1 (a) is a schematic block diagram of the pure water manufacturing apparatus 1 containing the electrical deionized water manufacturing apparatus (EDI) manufactured by this embodiment. FIG. 1B is a schematic configuration diagram of the EDI shown in FIG. Note that the illustrated EDI configurations are merely examples, and do not limit the present invention, and can be appropriately changed according to the purpose and application of the apparatus and the required performance.

  The pure water production apparatus 1 is for producing pure water by sequentially treating the water to be treated (raw water). As shown in FIG. 1A, the raw water tank 2, the membrane filtration device 3, and the electric type And a deionized water production apparatus 4.

  The membrane filtration device 3 removes impurities in the raw water supplied from the raw water tank 2 and generates permeated water. The raw water is separated into concentrated water containing impurities and permeated water from which impurities are removed. A reverse osmosis membrane (RO membrane) or a nanofiltration membrane (NF membrane). The membrane filtration device 3 includes a supply line L1 for supplying raw water from the raw water tank 2 to the membrane filtration device 3, a permeate water line L2 for circulating the permeate from the membrane filtration device 3, and a concentration from the membrane filtration device 3. A concentrated water line L3 through which water is circulated is connected. The concentrated water line L3 branches into a drainage line L4 that discharges part or all of the concentrated water flowing through the concentrated water line L3 to the outside and a reflux water line L5 that recirculates to the raw water tank 2. The raw water tank 2 is connected to a pretreatment device (not shown) for removing turbidity and dechlorination through the raw water supply line L6, and the pretreated raw water (for example, water having a conductivity of 1000 μS / cm or less). Is supplied as needed.

  A heat exchanger 5 and a pressure pump 6 are provided in the supply line L1. The heat exchanger 5 is provided in order to heat the raw water supplied to the membrane filtration device 3 during the sterilization process and generate hot water. The pressure pump 6 is provided to supply raw water stored in the raw water tank 2 to the membrane filtration device 3 together with a water pump (not shown) provided between the raw water tank 2 and the heat exchanger 5. ing. The rotation speed of the pressurizing pump 6 is controlled by an inverter (not shown), and also has a function of adjusting the supply pressure of raw water to the membrane filtration device 3. Valves V1 and V2 for switching the flow path of the concentrated water flowing through the concentrated water line L3 are provided in the drainage line L4 and the reflux water line L5, respectively.

  The electric deionized water production apparatus 4 is an apparatus that simultaneously performs deionization (demineralization) treatment of water to be treated by an ion exchanger and regeneration treatment of the ion exchanger. The electric deionized water production apparatus 4 is connected to the downstream side of the membrane filtration device 3 through the permeate line L2, and the permeated water from the membrane filtration device 3 is supplied as treated water. The electric deionized water production apparatus 4 includes a treated water line L7 that distributes treated water (deionized water) from the electric deionized water production apparatus 4 and supplies it to a treated water tank or point of use, and an electric deionized water. A concentrated water discharge line L8 for discharging the concentrated water from the ionic water production apparatus 4 to the outside is connected.

  The treated water line L7 is provided with a valve V3, and a treated water reflux line L9 is connected to the upstream side of the treated water line L7 via a valve V4. The treated water reflux line L9 is connected to the raw water tank 2 on the opposite side. Thereby, for example, when there is no demand for treated water (pure water) at the use point when the apparatus is activated or when the operation is resumed, treated water produced by the electric deionized water production apparatus 4 is returned to the raw water tank 2. Circulation operation can also be performed. The concentrated water discharge line L8 is provided with a valve V5, and a concentrated water reflux line L10 is connected to the upstream side of the concentrated water discharge line L8 via a valve V6. The concentrated water reflux line L10 is connected to the raw water tank 2 on the opposite side. Thereby, depending on the quality of the concentrated water from the electric deionized water production apparatus 4, part or all of the concentrated water can be returned to the raw water tank 2.

  As shown in FIG. 1B, the electric deionized water production apparatus 4 includes an anode chamber E1 having an anode 11, a cathode chamber E2 having a cathode 12, and an anode chamber E1 and a cathode chamber E2. A desalting chamber D provided on the anode 11, an anode side concentrating chamber C 1 adjacent to the desalting chamber D via the anion exchange membrane a 1 on the anode 11 side of the desalting chamber D, and a cation on the cathode 12 side of the desalting chamber D It has a desalting chamber D and an adjacent cathode side concentrating chamber C2 through an exchange membrane c1. The anode enrichment chamber C1 is adjacent to the anode chamber E1 via the cation exchange membrane c2, and the cathode enrichment chamber C2 is adjacent to the cathode chamber E2 via the anion exchange membrane a2.

  The desalting chamber D is divided into a first small desalting chamber D1 and a second small desalting chamber D2 by an intermediate ion exchange membrane m. The first small desalting chamber D1 is adjacent to the anode side concentrating chamber C1 via the anion exchange membrane a1, and the second small desalting chamber D2 is adjacent to the cathode side concentrating chamber C2 via the cation exchange membrane c1. is doing. The intermediate ion exchange membrane m is, for example, a single membrane of an anion exchange membrane or a cation exchange membrane, or a bipolar membrane.

  The desalting chamber D is filled with a granular cation exchanger CE and a granular anion exchanger AE. Specifically, the first small desalting chamber D1 is filled with the anion exchanger AE in a single bed form, and the second small desalting chamber D2 is filled with the cation exchanger CE and the anion exchanger AE. It is filled in the form of multiple beds. More specifically, the second small desalination chamber D2 is divided into two regions along the flow direction of the water to be treated, and the upstream region is filled with the cation exchanger CE in a single bed form, In the downstream region, the anion exchanger AE is filled in a single bed form. Examples of the cation exchanger filled in the desalting chamber D include cation exchange resins. Examples of the cation exchanger include weakly acidic cation exchangers and strongly acidic cation exchangers. Examples of the anion exchanger filled in the desalting chamber D include anion exchange resins. Examples of the anion exchanger include weakly basic anion exchangers and strong basic anion exchangers.

  The cation exchanger or anion exchanger is preferably a granular ion exchange resin in the production process. The granular ion exchange resin is a spherical ion exchange resin having a particle size of 0.1 mm to several mm.

  The anode-side enrichment chamber C1 and the cathode-side enrichment chamber C2 are each preferably filled with an ion exchanger in order to suppress the electrical resistance of the electrical deionized water production apparatus 4. In addition, the anode chamber E1 and the cathode chamber E2 are preferably filled with a conductive substance such as an ion exchanger, respectively, in order to suppress the electric resistance of the electric deionized water production apparatus 4. As an example, the anode-side enrichment chamber C1, the cathode-side enrichment chamber C2, and the cathode chamber E2 are filled with an anion exchanger, and the anode chamber E1 is filled with a cation exchanger.

  The permeate line L2 from the membrane filtration device 3 branches into a plurality (three in the illustrated example) and is connected to the first small desalting chamber D1, the anode-side concentration chamber C1, and the cathode-side concentration chamber C2, respectively. ing. The first small desalting chamber D1 forms a serial flow path with the second small desalting chamber D2, and its downstream side is connected to the treated water line L7. The anode side concentrating chamber C1 and the cathode side concentrating chamber C2 form a parallel flow path, and the downstream side thereof is connected to the concentrated water discharge line L8. Thus, the permeated water from the membrane filtration device 3 is supplied to the first and second small desalting chambers D1 and D2 as treated water, and is supplied as concentrated water to the anode side concentrating chamber C1 and the cathode side concentrating chamber C2. The In addition, although illustration is abbreviate | omitted, the line for supplying and discharging | emitting electrode water is also connected to the anode chamber E1 and the cathode chamber E2.

  The permeated water (treated water) supplied from the membrane filtration device 3 through the permeated water line L2 is freed of ionic components when passing through the desalting chamber D, and treated water (deionized water) is treated water line L7. To be supplied to treated water tanks or use points. At this time, the ionic component removed in the desalting chamber moves to the concentrating chambers C1 and C2 adjacent to the desalting chamber D due to a potential difference generated when a DC voltage is applied between the two electrodes 11 and 12. Specifically, the cation component is attracted to the cathode 12 side, passes through the cation exchange membrane c1 and moves to the cathode side concentration chamber C2, and the anion component is attracted to the anode 11 side and passes through the anion exchange membrane a1. Then, it moves to the anode side concentrating chamber C1. The ionic components thus moved to the concentration chambers C1 and C2 are taken into the concentrated water supplied to the concentration chambers C1 and C2, and are discharged to the outside through the concentrated water discharge line L8. However, depending on the quality of the concentrated water, a part or all of it may be returned to the raw water tank 2. On the other hand, in the desalting chamber D, a water dissociation reaction (a reaction in which water is dissociated into hydrogen ions and hydroxide ions) proceeds continuously. Hydrogen ions are exchanged with cation components adsorbed on the cation exchanger, and hydroxide ions are exchanged with anion components adsorbed on the anion exchanger. Thus, the cation exchanger and the anion exchanger filled in the desalting chamber D are regenerated.

  In addition, as described at the beginning, the illustrated configuration of the electric deionized water production apparatus 4 is merely an example, and the configuration (number, arrangement, etc.) of each room according to the purpose and application of the apparatus and the required performance. ) Or a flow path configuration, or a valve or a measuring instrument is added as appropriate. For example, two or more desalting chambers may be provided. In this case, the desalting chamber and the concentration chamber are alternately provided via a cation exchange membrane or an anion exchange membrane, and two or more desalting chambers form a series or parallel flow path. Further, the filling form of the cation exchanger and the anion exchanger in the desalting chamber is not limited to the illustrated one. For example, the first small desalting chamber is filled with the cation exchanger in a single bed form, Each of the small desalting chambers may be filled with an anion exchanger and a cation exchanger in a single bed form.

  In the above example, the desalting chamber D is filled with the cation exchanger CE and the anion exchanger AE. However, the present invention is not limited thereto, and only the cation exchanger may be filled. Alternatively, only the anion exchanger may be filled. That is, the desalting chamber may be filled with at least one of a cation exchanger and an anion exchanger as an ion exchanger.

  An embodiment of an EDI manufacturing method used in the pure water manufacturing apparatus 1 as described above will be described. In this embodiment, after assembling EDI in which a granular ion exchanger is filled in a demineralization chamber defined by an ion exchange membrane, heat is applied to the ion exchange membrane and the ion exchanger filled in the demineralization chamber. Perform water treatment.

  Specifically, it is as follows. First, a granular ion exchanger is filled in a desalting chamber defined by an ion exchange membrane (filling step, step S11 in FIG. 6). For example, in the case of EDI shown in FIG. 1B, a granular cation exchanger CE is filled in the first small desalting chamber D1 partitioned by the anion exchange membrane a1 and the intermediate ion exchange membrane m. In addition, the granular small anion exchanger AE and the granular cation exchanger CE are filled in series into the second small desalting chamber D2 partitioned by the intermediate ion exchange membrane m and the cation exchange membrane c1. At least one of the anode-side enrichment chamber C1, the cathode-side enrichment chamber C2, the anode chamber E1, and the cathode chamber E2 may be filled with an ion exchanger and used for the subsequent hot water treatment.

  Next, EDI is assembled using a desalting chamber filled with an ion exchange resin. After the assembly of EDI, the granular ion exchanger filled in the desalting chamber and the ion exchange membrane that defines the desalting chamber are brought into contact with hot water at 80 ° C. or higher and lower than boiling point for 5 hours or longer (hot water treatment step). , Step S12 in FIG. For example, hot water is supplied from the permeate water line L2 shown in FIG.

  The hot water treatment is to bring hot water into contact with at least the ion exchanger filled in the desalting chamber and the ion exchange membrane that defines the desalting chamber. Although the method of making hot water contact is not limited, For example, passing hot water or immersing in hot water is mentioned. Passing hot water means bringing it into contact with flowing hot water. To immerse in hot water is to contact the stored hot water. The stored hot water may be stirred or circulated. In addition, it is necessary to use high-purity water such as RO (reverse osmosis membrane) permeated water, EDI-treated water, or pure water as the hot water.

  It is considered that passing water is more effective in removing impurities such as an organic component (TOC) derived from the ion exchanger than by immersing. In addition, when hot water treatment is performed after the EDI is assembled, it is advantageous because hot water can be passed through a route for treating the water to be treated. The heated hot water may be disposable. Or you may collect | recover and circulate and recycle the hot water. Even if it is circulated, the amount of impurities such as TOC mixed in the hot water is very small and does not adversely affect the apparatus or ion exchange resin. Therefore, it is preferable to circulate in order to save hot water. Although the water flow rate is not limited, it is preferably at least equal to or higher than the water flow rate at which water flows evenly in the desalting chamber. For example, it is preferable that the water flow rate is about the same as the normal water treatment rate.

  Similarly, when immersing in hot water, the hot water in which the ion exchanger is immersed may be replaced as appropriate, and the replaced hot water may be disposable or circulated and reused.

  The contact time is preferably 5 hours or longer. This is because the effect is almost achieved if the contact time is 5 hours or longer. You may make it contact for 5 hours or more continuously. Alternatively, the total time may be 5 hours or longer by intermittent contact. Intermittent means, for example, heating to a treatment temperature of 80 ° C. or higher while circulating water to avoid drying, raising the temperature to the treatment temperature, maintaining the temperature and performing a hot water treatment, and then heating. This is a method of repeating the processing cycle such as stopping and lowering the temperature. If the contact is made for too long, the deterioration of the ion exchanger proceeds and the effect gradually decreases. Therefore, the contact time is preferably 15 hours or less. Further, the contact time is more preferably 5 hours to 10 hours.

  By performing such hot water treatment on the ion exchanger and the ion exchange membrane, it is possible to shorten the rise time of the treated water quality when the ion exchange water is first produced. That is, the specific resistance value of the treated water obtained by treating the for-treatment water becomes almost maximum immediately after the hot water treatment.

  As described above, in the prior art, the specific resistance value of treated water treated with EDI slowly increases for several hours to several tens of hours or more after the first treatment of treated water, and then reaches a maximum value. And reaches a steady value (constant value). This is because when salt-type ion exchange resins are used, salt components (Na, Cl, etc.) leak from salt-type ion exchangers such as Na-type and Cl-type into demineralized water, resulting in poor water quality. This is probably because it takes time to improve.

  However, by performing the hot water treatment according to the present embodiment, this rise time can be greatly shortened. For this reason, the inventors treated the ion exchanger with hot water, thereby improving the ion exchange reactivity by removing the TOC of the ion exchanger and removing a part of the crosslinked structure of the resin of the ion exchanger. It is thought that this is because a synergistic effect with the effect of promoting the movement of ions can be obtained by cutting and irreversibly swelling to increase the area where the resins or the resin and the film are in close contact with each other. As the time of the hot water treatment increases, the differential pressure of the hot water passing through the ion exchanger gradually increases.

  Accordingly, the temperature of the hot water is preferably 80 ° C. or higher in order to promote cleaning of the ion exchanger and irreversible swelling. In a boiled state, sufficient swelling treatment cannot be performed, and deterioration of the ion exchanger may progress. Therefore, hydrothermal treatment is performed at a temperature lower than the boiling point of water (at atmospheric pressure, less than 100 ° C.). More preferably, it is 85 degreeC to 95 degreeC, and 85 degreeC to 90 degreeC is still more preferable.

  The hot water treatment is performed on at least the ion exchanger filled in the desalting chamber and the ion exchange membrane that defines (compartments) the desalting chamber. Further, if an ion exchanger is arranged in the concentration chamber or the electrode chamber, the ion exchange membrane that defines the ion exchanger and the chamber may be subjected to hydrothermal treatment. In the case of this embodiment, since the hot water treatment is performed after the EDI is assembled, the hot water treatment can be performed by passing hot water through the treatment path of the water to be treated. For example, in the EDI having the structure shown in FIG. 1B, hot water is supplied from the permeate line L2 to the first small desalting chamber D1. The hot water supplied to the first small desalting chamber D1 is discharged from the treated water line L7 via the second small desalting chamber D2. The treated water line L7 is temporarily connected so as to be connected to the hot water receiving tank. The hot water that has returned to the hot water receiving tank can be supplied again to the first small desalination chamber D1 by adjusting the temperature.

  Not only the first small desalting chamber D1, but also the anode-side enrichment chamber C1 and the cathode-side enrichment chamber C2 may be supplied simultaneously. The hot water supplied to the anode side concentrating chamber C1 and the cathode side concentrating chamber C2 is discharged from the concentrated water discharge line L8. Therefore, the concentrated water discharge line 8 is also temporarily connected so as to be connected to the hot water receiving tank. The hot water that has returned to the hot water receiving tank can be supplied again to the first small desalting chamber D1, the anode-side concentrating chamber C1, and the cathode-side concentrating chamber C2 by adjusting the temperature. Further, hot water may be passed through the anode chamber E1 and the cathode chamber E2.

  The ion exchanger filled in the desalting chamber D is preferably in a dry or salt form. This is because the filling amount can be increased as compared with the case of filling the wet and regenerated resin. In the case of using a salt-type ion exchanger, it is preferable that the salt-type ion exchanger is finally regenerated by chemicals or electricity.

  In this way, EDI that has been subjected to hot water flow treatment for a predetermined time can shorten the rise time of the treated water quality when ion-exchanged water is first produced. Moreover, the specific resistance value of treated water can be increased as compared with those not treated with hot water. In addition, since all the members in contact with the liquid are washed by the water-passing type hot water treatment, a secondary effect that the device can be used as a clean device from the beginning can be obtained. EDI preferably uses a heat-resistant member in order to suppress deterioration due to heat.

  When soaking in hot water instead of passing water, hot water is supplied to the desalting chamber D, the anode-side concentrating chamber C1, the cathode-side concentrating chamber C2, the anode chamber E1, and the cathode chamber E2, for example, and maintained at a predetermined temperature. You may do it. The ion exchanger may be of any type. In this case, the same effect as described above can be obtained.

  In the said embodiment, after assembling EDI, the ion-exchange membrane and the ion exchanger with which the desalination chamber were filled were hydrothermally treated. However, the present invention is not limited to this, and hydrothermal treatment may be performed at the next stage in which a desalination chamber defined by an ion exchange membrane is filled with a granular ion exchanger. In this case, the hot water treatment is performed in the state of the desalination chamber unit filled with the ion exchanger. The method of the hot water treatment may be a water flow treatment or an immersion treatment. And EDI can be assembled using the desalination chamber unit which finished hot water processing.

(Embodiment 2)
Before the assembly of the desalting chamber unit, hot water treatment may be performed on each of the ion exchanger in the desalting chamber and the ion exchange membrane that partitions the desalting chamber. In this case, as shown in FIG. 7, first, each of the granular ion exchanger and the ion exchange membrane is hydrothermally treated with hot water at 80 ° C. or higher and lower than boiling point for 5 hours or longer (hot water treatment step). , Step S21 in FIG. Next, the granular ion exchanger subjected to the hot water treatment is filled in the desalting chamber defined by the ion exchange membrane subjected to the hot water treatment (filling step, step S22 in FIG. 7).

  The hot water treatment can be performed, for example, by putting an ion exchanger before assembly and an ion exchange membrane that partitions the desalting chamber into a hot water tank. The hot water in the hot water tank may be stirred or circulated. Moreover, you may make it contact with the hot water which flows through an ion exchanger and an ion exchange membrane. In the hydrothermal treatment, the ion exchange membrane and the ion exchanger may be separated, or the hydrothermal treatment may be performed separately or together. Also in this embodiment, the ion exchanger to be subjected to hot water treatment may be wet or dry. Further, it may be a regenerated form or a salt form. Then, after filling the desalting chamber defined by the ion exchange membrane subjected to the hot water treatment with the granular ion exchanger subjected to the hot water treatment, it is assembled as EDI (step S23 in FIG. 7).

  By assembling EDI using ion exchange membranes and ion exchangers that have been subjected to hydrothermal treatment for a predetermined time, it is possible to shorten the rise time of the treated water quality when first producing ion exchange water. Moreover, the specific resistance value of treated water can be increased as compared with those not treated with hot water. As described above, the hot water treatment can be performed at various timings.

(Example)
Examples of the present invention will be described below.
As shown in FIG. 2 (a), a test stack 23 simulating an EDI desalting chamber, an anode-side concentrating chamber, and a cathode-side concentrating chamber, a water tank 20 for storing (hot) water, and hot water are heated. A hot water treatment test apparatus having a heater 21 was manufactured.

  Two test stacks 23 having the same configuration filled with a wet (salt-type) anion exchange resin AE and a dry (regenerated) cation exchange resin CE were produced. As shown in FIG. 2A, the test stack 23 includes a desalting chamber 23a, an anode-side enrichment chamber 23b, and a cathode-side enrichment chamber 23c. As shown in detail in FIG. 2B, the desalting chamber 23a includes a small desalting chamber filled with an anion exchange resin AE, and a small desalting chamber filled with a cation exchange resin CE and an anion exchange resin AE in series. Are connected in this order. This is the same as the configuration shown in FIG. The test stack 23 was used for the test by electrically regenerating the salt-type ion exchange resin after filling with the ion exchange resin. As the test stack 23, chamber members and ion exchange membranes having heat resistance specifications were used.

The pure water in the water tank 20 was heated by the heater 21 and supplied to one test stack 23 by a liquid feed pump (not shown). Specifically, hot water was supplied to the supply lines 24 of the desalting chamber 23a, the anode-side concentration chamber 23b, and the cathode-side concentration chamber 23c. The water flow rate (SV) was 150-200 h ⁻¹ . The hot water that passed through the desalting chamber 23a, the anode-side concentrating chamber 23b, and the cathode-side concentrating chamber 23c was returned to the water tank 20 through the drain line 25 and circulated for reuse.

  In one hot water treatment, as shown in FIG. 3, 25 ° C. pure water in the water tank 20 is heated by the heater 21 and circulated until it becomes 87 ° C. hot water. After the temperature reached, the circulating hot water treatment was performed for 1 hour while maintaining the temperature, and the heating was stopped and the temperature was lowered for 1 hour while circulating until reaching 25 ° C. For a total of 3 hours, (hot) water was circulated and passed through the test stack 23. Such a hot water treatment cycle was repeated 5 times continuously (hot water treatment for a total of 5 hours), and then the water to be treated at normal temperature (25 ° C.) was passed through to measure the specific resistance value of the treated water. At this time, the water to be treated was passed through the first-stage reverse osmosis membrane. The flow of the treated water was continued until the specific resistance value of the treated water became constant. In addition, since the temperature raising / lowering time between 80 degreeC and 87 degreeC is short and can be disregarded, it is not included in processing time. Incidentally, the rate of temperature increase / decrease was 1 ° C./min, and it took 7 minutes to increase the temperature from 80 ° C. to 87 ° C. and 7 minutes to decrease the temperature from 87 ° C. to 80 ° C. in one hot water treatment. Therefore, in the hot water treatment 5 times, the temperature raising / lowering time of 80 ° C. or higher was (7 + 7) × 5 = 70 minutes.

  After the specific resistance value of the treated water becomes constant, the hot water treatment of 5 times is repeated in the same manner as described above (total 10 hours of hot water treatment), and then water at normal temperature (25 ° C.) is treated with the specific resistance of the treated water. Water was passed until the value became constant. Further, after the specific resistance value of the treated water becomes constant, the hot water treatment of 5 times is repeated again in the same manner as described above (a total of 15 hours of hot water treatment), and water at normal temperature (25 ° C.) is treated with the treated water. Water was passed until the specific resistance value became constant. As will be described later, in the examples, the specific resistance value of the treated water was not significantly changed even when the water was passed for about 100 hours. Therefore, in the examples, water was passed until it was confirmed that there was no change in the specific resistance value. The change with time of the specific resistance value of the treated water in the case of 5 hydrothermal treatments is shown in FIG.

(Comparative example)
The other test stack 23 performs a conventional start-up operation of passing water to be treated at room temperature (25 ° C.) without performing hot water treatment, and measures until the specific resistance value of the treated water reaches a constant value. did. The treated water was passed through the first-stage reverse osmosis membrane. FIG. 4 shows the change over time in the specific resistance value of the treated water in the case of zero hot water treatment.

  Table 1 shows the specific resistance value (initial specific resistance value) of the treated water immediately after the start of normal temperature water flow in Examples and Comparative Examples. Data for which the number of hot water treatments is zero is the initial specific resistance value of the treated water of the comparative example that is not subjected to hot water treatment. The numbers of hot water treatments 5 times, 10 times, and 15 times are the initial specific resistance values of the treated water in the examples. Since the hot water treatment time per hot water treatment is one hour, the number of hot water treatments and the hot water treatment time are the same numerical values. As described above, since the specific resistance value hardly changed with time in the examples, the specific resistance value and the steady value of the treated water immediately after the hot water treatment are the same. As shown in FIG. 4, in the embodiment, a substantially maximum specific resistance value can be obtained immediately after the hot water treatment. That is, there is almost no rise time.

  As shown in FIG. 4, when the number of hot water treatments was 0, it took 150 hours or more until the specific resistance value became a constant value. The constant value (steady specific resistance value) was 17.5 (MΩ · cm) as shown in FIG. On the other hand, when the number of hot water treatments is 5, the specific resistance value is a constant value immediately after the start of the treatment, and the value is also 18.0 (MΩ · cm) as shown in Table 1, which is a steady-state ratio of the comparative example. It was higher than the resistance value. Although not shown in the graph, when the number of hot water treatments is 10 or 15, the specific resistance value is almost constant immediately after the start of the treatment, and the initial specific resistance value is 17 as shown in Table 1, respectively. .8, 17.7 (MΩ · cm).

  FIG. 5 shows that the specific resistance value of the treated water of the test stack of 0 times (comparative example without hot water treatment), 5 times, 10 times, and 15 times (above examples) is a constant value. This is a graph of the steady-state resistivity value when Both are specific resistance values of treated water after several days.

  The specific resistance value of the treated water immediately after hydrothermal treatment for 5 hours (5 times) in the examples is 18.0 (MΩ · cm), and the value is almost unchanged even after time has passed as shown in FIG. There wasn't. Similarly, when the number of hot water treatments was 10 and 15, the value was almost constant immediately after the start of treatment. This indicates that in the examples, the ion exchange capacity of the ion exchange resin is maximized immediately after the start of treatment of the water to be treated.

  On the other hand, when the number of hot water treatments was 0, it took a long time to reach a certain value, and the certain value was also lower than that of the example. That is, it was found that the hot water treatment can further increase the ion exchange capacity of EDI and can shorten the rise time of the treated water quality.

  As can be seen from FIG. 4, in the comparative example (the number of hot water treatments is 0), the rise is in the middle even after 15 hours, and the specific resistance value of the treated water when the hot water treatment is performed for 5 hours (Example) It doesn't reach. Therefore, it can be seen that the effect in the example is not simply obtained by the length of time (3 hours × 5 = 15 hours) in which water is passed, but the effect of the hot water treatment.

  FIG. 5 shows that the number of hot water treatments is preferably 5 times or more (treatment time of 5 hours or more). However, as the treatment time increased, the steady-state specific resistance value of the treated water gradually decreased. From FIG. 5, when the number of hot water treatments exceeds 15 (treatment time 15 hours), it is expected that the steady-state resistivity value approaches that when no hot water treatment is performed. Therefore, the hot water treatment time is preferably within 15 hours. Further, it can be seen that the hot water treatment time is more preferably 5 hours to 10 hours.

1 Pure water production equipment 2 Raw water tank 3 Membrane filtration equipment 4 Electric deionized water production equipment (EDI)
5 Heat Exchanger 6 Pressure Pump 11 Anode 12 Cathode 20 Water Tank 21 Heater 23 Test Stack 24 Supply Line 25 Drain Line D Desalination Chamber D1 First Small Desalination Chamber D2 Second Small Desalination Chamber C1 Anode Side Concentration Chamber C2 Cathode side enrichment chamber E1 Anode chamber E2 Cathode chamber a1, a2 Anion exchange membrane c1, c2 Cation exchange membrane m Intermediate ion exchange membrane L1 Supply line L2 Permeate line L3 Concentrated water line L4 Drain line L5 Reflux water line L6 Raw water supply Line L7 Treated water line L8 Concentrated water discharge line L9 Treated water reflux line L10 Concentrated water reflux line V1-V6 Valve

Claims (3)

A method for producing an electrical deionized water production apparatus, comprising: a cathode and an anode facing each other; and a demineralization chamber filled with a granular ion exchanger defined by an ion exchange membrane between the cathode and the anode. Because
A filling step of filling a granular ion exchanger into a desalting chamber defined by an ion exchange membrane;
A hydrothermal treatment step of bringing the ion exchanger filled in the desalting chamber and the ion exchange membrane into contact with hot water having a boiling point of 80 ° C. or higher and lower than the boiling point for 5 hours or more;
The manufacturing method of the electrical deionized water manufacturing apparatus containing this. A method for producing an electrical deionized water production apparatus, comprising: a cathode and an anode facing each other; and a demineralization chamber filled with a granular ion exchanger defined by an ion exchange membrane between the cathode and the anode. Because
A hydrothermal treatment step of contacting each of the granular ion exchanger and the ion exchange membrane with hot water of 80 ° C. or higher and lower than boiling point for 5 hours or more;
A filling step of filling the hot water treated ion exchanger into a desalting chamber defined by the hot water treated ion exchange membrane;
The manufacturing method of the electrical deionized water manufacturing apparatus containing this. The said hot water treatment process is a manufacturing method of the electrical deionized water manufacturing apparatus of Claim 1 or 2 which is the time for which hot water is made to contact within 15 hours.

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