JP5098216B2 - Electric regenerative pure water production apparatus and pure water production method - Google Patents

Description

  The present invention relates to an electric regenerative pure water production apparatus and a pure water production method.

  Conventionally, an electroregenerative pure water production apparatus using a combination of an ion exchanger and an ion exchange membrane and an electrodialysis action has been proposed. This device was invented by paying attention to the fact that a water-containing ion exchanger is a good conductor, and is basically sandwiched between an anion exchange membrane and a cation exchange membrane of an electrodialysis device. The desalting chamber is filled with an ion exchanger. And the to-be-processed water which should be desalted is distribute | circulated, applying a voltage to a desalination chamber, and a pure water is obtained. According to the electric regeneration type pure water production apparatus, there is an advantage that a regenerant necessary for the method for producing pure water using an ion exchange resin is not required.

  The present applicant has proposed an apparatus in which a conductive substance is added to a mixture of a cation exchanger and an anion exchanger accommodated in a desalting chamber (see, for example, Patent Document 1). In addition, an apparatus in which a conductive substance is accommodated in the concentration chamber and / or the electrode chamber has also been proposed (see, for example, Patent Documents 1 and 2). All of these improved devices are electrically stable, and are therefore aimed at stabilizing without deteriorating the quality of the treated water, and reducing the power consumption. The effect is prominent when the number of built-in chambers of the desalting chamber and the concentration chamber is increased.

  However, the conventional electric regenerative pure water production apparatus has no problem in terms of removing the strong electrolyte, but is insufficient in terms of removing the weak electrolyte.

Japanese Patent Laid-Open No. 9-24374 JP 2001-137856 A JP 2001-137859 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric regenerative pure water producing apparatus with improved weak electrolyte removal efficiency.

That is, the first gist of the present invention is a plurality of sets of anion exchange membranes and cation exchange membranes that are sequentially formed between an anode chamber having an anode and a cathode chamber having a cathode. In an electric regenerative pure water production apparatus comprising a desalting chamber and a concentrating chamber and containing a mixture of a cation exchanger and an anion exchanger in the desalting chamber, an anode and / or a or it resides in an electric regenerative pure water production apparatus by the cathode a plurality of stages arranged and wherein the formed Rukoto.

  And the 2nd summary of this invention exists in the manufacturing method of the pure water characterized by using said electric regeneration type pure water manufacturing apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the electric regeneration type | formula pure water manufacturing apparatus with which the removal efficiency of weak electrolyte was improved is provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall schematic view of a front view in a vertical section of an example of an electric regeneration type pure water production apparatus of the present invention.

  The basic configuration of the electric regeneration type pure water production apparatus (1) of the present invention is that an anion exchange membrane (61) and a cation exchange membrane (71) are provided between an anode chamber (3) and a cathode chamber (5). It consists of a plurality of sets of desalting chambers (81), (82)... And concentration chambers (91), (92)... An electrode to be described later is provided.

  That is, a desalination chamber (81) is configured by being sandwiched between an anion exchange membrane (61) and a cation exchange membrane (71), and similarly, an anion exchange membrane (62) and a cation exchange membrane (72). A second desalting chamber (82) is formed between the two. In this way, in the illustrated apparatus, five desalting chambers are formed. On the other hand, a first concentration chamber (91) is formed between the cation exchange membrane (71) and the anion exchange membrane (62). Similarly, the cation exchange membrane (72) and the anion exchange membrane (63) are formed. ) To form a second concentration chamber (92). In this way, in the case of the illustrated apparatus, four concentration chambers are formed. And the mixture (A) of a cation exchanger and an anion exchanger is accommodated in each of the five desalting chambers.

  In each of the five demineralization chambers, water to be treated (water to be deionized) is supplied from the demineralization chamber side inflow pipe (131). The treated water (deionized water) flows out from the demineralization chamber side outflow pipe (132). In four concentration chambers, water to be treated is supplied from the concentration chamber side inflow pipe (141) in parallel. The treated water supplied to each concentrating chamber is concentrated and discharged from the concentrating chamber side outflow pipe (142) as concentrated water. Simultaneously with the supply to the concentrating chamber, water to be treated was introduced from the anode chamber side inflow pipe (121) to the anode chamber (3) and from the cathode chamber side inflow pipe (123) to the cathode chamber (5). The gas is discharged from the anode chamber side outflow pipe (122) and the cathode chamber side outflow pipe (124).

  As an ion exchange membrane for forming a desalination chamber and a concentration chamber, those used in ordinary electrodialyzers are used. For example, trade names “Selemion” (Asahi Glass Co., Ltd.), “Neocepta” (Tokuyama) And commercial products such as “Aciplex” (manufactured by Asahi Kasei Co., Ltd.).

  As the ion exchanger (A) filled in the desalting chamber, an anion exchange resin and a cation exchange resin that are used for a desalting treatment during normal pure water production can be used. It is advantageous to use ion exchange fibers having a large specific surface area and an efficient ion exchange reaction. Specific examples of such ion exchange fibers include those obtained by introducing ion exchange groups into a composite fiber of a polystyrene fiber and an auxiliary agent, those obtained by introducing an ion exchange group into a vinyl alcohol fiber base, and polyolefin fibers. Commercially available products such as those in which ion-exchange groups are introduced using radiation graft polymerization after irradiation with radiation can be used.

  In addition, the ion exchange resin is appropriately selected from ion exchange resins employed for normal pure water production. For example, “Diaion (registered trademark) SK1B” and “PK208” as strong acid cation exchange resins, and “Diaion SA10A” and “PA316” as strong base anion exchange resins. Etc.

  The above-mentioned ion exchanger may be used in either a regeneration type or a salt type, but it is preferable to use a regeneration type in order to speed up the water quality.

  The concentration chamber and / or electrode chamber preferably contains a mixture of a cation exchanger and an anion exchanger (not shown). With such a configuration, the concentration chamber and / or the electrode chamber are electrically more stable, so that the water application quality is stabilized without lowering the quality of the treated water without changing the voltage application conditions, and the power consumption is reduced. I can do it.

  As the mixture of the cation exchanger and the anion exchanger used in the concentration chamber and / or the electrode chamber, the same ones as described above as the packing for the desalting chamber are used.

The electric regenerative pure water production apparatus of the present invention is characterized by an electrode arrangement structure and a voltage application method. That is, in the conventional electric regenerative pure water production apparatus, the anode chamber (3) and the cathode chamber (5) are each provided with one anode and a cathode. In the water production apparatus, a plurality of anodes and / or cathodes are arranged along the flow direction of raw water. In the illustrated example, two anodes (21), (22) and cathodes (41), (42) are arranged in the anode chamber (3) and the cathode chamber (5), respectively .

  FIG. 2 is an explanatory view showing an electrode arrangement structure and a current flow of the electric regenerative pure water producing apparatus exemplified in FIG. 1, and shows a series circuit incorporating a plurality of electrodes. In this case, as a result of the series circuit, the current between the electrodes located on the upstream side in the flow direction of the raw water (between the anode (22) and the cathode (42)) is between the electrodes located on the downstream side (anode (21 ) And the cathode (41)).

  FIG. 3 is an explanatory diagram showing an electrode arrangement structure and a current flow of the electric regenerative pure water producing apparatus according to the present invention, and shows two series circuits each incorporating one set of electrodes. In this case, the current between the electrodes located on the upstream side in the flow direction of the raw water (between the anode (22) and the cathode (42)) is passed between the electrodes located on the downstream side (the anode (21) and the cathode (41)). Can be operated at the same value as the current of (between).

  FIG. 4 is an explanatory view showing an electrode arrangement structure and a current flow of the electric regenerative pure water producing apparatus of the present invention, and shows a parallel circuit incorporating two pairs of electrodes. In this case, by disposing a predetermined resistance (R) in front of the anode (21) located on the downstream side in the flow direction of the raw water, between the electrodes located on the upstream side (the anode (22) and the cathode (42)) A sufficient current can also be passed. In addition, you may arrange | position said resistance (R) after the cathode (41) located in the downstream of the flow direction of raw | natural water.

  FIG. 5 is an explanatory view showing the electrode arrangement structure and the current flow of the electric regenerative pure water production apparatus of the present invention, and includes two anodes (21) and (22) and one common cathode (43). The captured parallel circuit is shown. That is, in the example shown in FIG. 4, a common cathode (43) is used instead of the cathodes (41) and (42). Although not shown, in the example shown in FIG. 4, one common anode can be used instead of the anodes (21) and (22). In this case, the resistance (R) is the flow direction of the raw water. It is arrange | positioned after the cathode (41) located in the downstream.

  In short, the characteristics of the electric regenerative pure water production apparatus of the present invention are summarized as follows. That is, in the case of a conventional apparatus in which one anode and one cathode are respectively disposed in the anode chamber (3) and the cathode chamber (5), the electrolyte concentration in the treated water (deionized water) in the desalting chamber is the raw water. Gradually decreases toward the downstream side in the flow direction. As a result, the resistance of the desalting chamber is gradually reduced. Although this principle is not necessarily clarified, the voltage required to move sodium ions, chloride ions, etc. to the concentration chamber moves the voltage required for hydrolysis and hydrogen ions and hydroxide ions to the concentration chamber. This is considered to be due to the fact that it is larger than the total voltage required for the above. As a result, the current concentrates on the downstream side in the flow direction of the raw water and hardly passes on the upstream side, so that the desalination efficiency decreases. Such a phenomenon appears remarkably in the removal of the weak electrolyte that takes time in desalting. Therefore, the present invention improves the electrode arrangement structure and the current application method so that a sufficient current can flow even upstream in the flow direction of the raw water. As a result, in the electric regeneration type pure water production apparatus of the present invention, the strong electrolyte is efficiently removed upstream in the flow direction of the raw water, the weak electrolyte removal zone is lengthened, and the weak electrolyte is removed.

  The current value applied to the electric regenerative pure water production apparatus of the present invention is usually 0.1 to 20 A, preferably 1 to 5 A, and more preferably 2 to 4 A (however, the current value is half in the case of a series circuit). The voltage is 700V or less. Moreover, as said electrode, the electrode plate normally used by electrodialysis can be used. For example, a plate made of titanium on a plate made of platinum on the anode can be used as the anode, and a plate made of SUS316 can be used as the cathode. Needless to say, the surface of each electrode plate may be a flat one, or any one processed into a net or irregular shape in order to disperse current uniformly.

  In the electric regenerative pure water producing apparatus of the present invention, a part of the upstream side (inlet side) of the desalting chamber is a strong electrolyte desalting zone, and a part of the upstream side (inlet side) and downstream side of the desalting chamber (Exit side) functions as a weak electrolyte removal zone. The mechanism is not necessarily clear, but is estimated as follows. That is, it is generally known that in an electric regenerative pure water production apparatus, a strong electrolyte is first removed and then a weak electrolyte is removed. Therefore, by applying the above principle and forcibly applying current to the upstream side (inlet side) of the desalination chamber, the strong electrolyte is removed at an early stage, and the weak electrolyte removal zone is lengthened, Weak electrolyte is efficiently removed.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.
Example 1:

  1 is an electric regeneration type pure water production apparatus having a structure as shown in FIG. 1, comprising a series circuit as shown in FIG. 2, using a device comprising 30 demineralization chambers and 31 concentration chambers, The experiment was conducted. The desalting chamber is 390 mm long, 130 mm wide and 2 mm thick, and the concentrating chamber is 390 mm long, 130 mm wide and 2 mm thick.

  As the anion exchange membrane, Selemion AMD (Asahi Glass Co., Ltd., Selemion is a registered trademark of the company) is used, and its dimensions are 390 mm in length and 130 mm in width. As the cation exchange membrane, Selemion CMD [manufactured by Asahi Glass Co., Ltd.] is used, and its dimensions are 390 mm in length and 130 mm in width.

  As the mixture (A) of the ion exchanger, a strongly acidic cation exchange fiber (“IEF-SC” manufactured by Nichibi Co., Ltd.) and polyvinyl alcohol in which polyvinyl alcohol is used as a matrix and sulfonic acid oxide of styrene-divinylbenzene is uniformly dispersed. Both ion exchange fibers of a strong base anion exchange fiber (“IEF-SA” manufactured by Nichibi Co., Ltd.) formed by adding a trimethylammonium group to the main chain are mixed in the same amount with an exchange capacity, and this is used as an inert synthetic fiber. After mixing the polyester fiber at a ratio of 50%, a non-woven fabric was used.

  As the anodes (21) and (22), a plate made of titanium with platinum plating was used, and as the cathodes (41) and (42), a plate made of SUS316 was used. The dimensions of the anodes (21) and (22) were 190 mm in length and 130 mm in width, respectively, and the distance between the tip of the anode (21) and the tip of the anode (22) was 10 mm. Similarly, the dimensions of the cathodes (41) and (42) were 190 mm in length and 130 mm in width, respectively, and the distance between the tip of the cathode (41) and the tip of the cathode (42) was 10 mm.

  A mixture (A) of ion exchangers was accommodated between the anion exchange membrane and the anion exchange membrane in the concentration chamber.

  As water to be treated, RO (reverse osmosis membrane) treated water (electric conductivity: 20 μS / cm) of Yokohama City was used. The analysis value of this RO treated water is as shown in Table 1 described later.

  The treated water was passed through the desalting chamber inflow pipe (131) into the desalting chamber at LV 25 m / h. Similarly, water to be treated was supplied to both electrode chambers and the concentration chamber at the same flow rate as the supply rate to the desalting chamber. A DC voltage was applied simultaneously with water flow, and 2 A and 98 V were passed through the series circuit shown in FIG. The treated water flowing out from the desalting chamber was analyzed immediately after the steady state was reached. The results are shown in Table 1.

Comparative Example 1:
In Example 1, the circuit was changed to a circuit using only the anode (21) and the cathode (41), and the same operation as in Example 1 was performed except that 4A and 54V were passed. Table 1 shows the analysis results of the treated water flowing out from the desalination chamber.

Schematic diagram of an entire vertical vertical front view of an example of the electric regenerative pure water production apparatus of the present invention Explanatory drawing which shows the electrode arrangement structure and electric current flow of the electric regeneration type pure water manufacturing apparatus illustrated in FIG. Other explanatory drawing which shows the electrode arrangement structure and electric current flow of the electric regeneration type pure water manufacturing apparatus of this invention Other explanatory drawing which shows the electrode arrangement structure and electric current flow of the electric regeneration type pure water manufacturing apparatus of this invention Other explanatory drawing which shows the electrode arrangement structure and electric current flow of the electric regeneration type pure water manufacturing apparatus of this invention

Explanation of symbols

1: Electrodialysis tank body 21: Anode 22: Anode 3: Anode chamber 41: Cathode 42: Cathode 43: Common cathode 5: Cathode chamber 61: Anion exchange membrane 71: Cation exchange membrane 81: Desalination chamber 91: Concentration Chamber 121: Anode chamber inflow tube 122: Anode chamber outflow tube 123: Cathode chamber inflow tube 124: Cathode chamber outflow tube 131: Desalination chamber inflow tube 132: Desalination chamber outflow tube 141: Concentration chamber inflow tube 142: Concentration chamber outflow Tube A: Mixture of ion exchangers

Claims (3)

It consists of a plurality of demineralization chambers and concentrating chambers formed in sequence by alternately arranging anion exchange membranes and cation exchange membranes between an anode chamber with an anode and a cathode chamber with a cathode. in the electric regenerative water purifying apparatus comprising housed mixture of cation exchanger and anion exchanger salts chamber, formed by a plurality of stages arranged anode and / or cathode in the direction of the flow of the raw water Rukoto An electric regenerative pure water production apparatus characterized by   The electric regenerative pure water production apparatus according to claim 1, wherein a mixture of a cation exchanger and an anion exchanger is accommodated in the concentration chamber and / or the cathode chamber.   A method for producing pure water, characterized in that the electric regenerative pure water production apparatus according to claim 1 or 2 is used.

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