JP2006198562A - Electrode device and electrolytic cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode device and an electrolytic cell which can be used for a device performing electrodialysis of water or an electrolyte-containing solution to continuously generate high-purity electrolytic water. <P>SOLUTION: The electrode device comprises a cylindrical electrode 9a which is made of a corrosion-resistant metal and carries a conductive catalytic which coats at least one of its outer surface and inner surface, a cylindrical diaphragm 8 which covers the outside of the cylindrical electrode, and an inflow port 12 and a discharge port 13 for continuously feeding liquid to the inside of the diaphragm. The cylindrical electrode 9a may have a number of holes on the surface. The diaphragm 8 may be a diaphragm having a sufficient strength for supporting its shape by itself. The electrode device has an independent structure, which facilitates its attachment to and detachment from the electrolytic cell. The number of the electrode devices for a cathode and an anode, their layout, and the like can be freely designed according to the purpose and capacity of the electrolytic cell. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrode device and an electrolytic cell that can be used in a device that continuously produces high-purity electrolyzed water by electrodialysis of, for example, water or a solution containing an electrolyte.

  An example of an electrolyzed water generating device that generates electrolyzed water using an appropriate electrolyte is disclosed, for example, in Patent Document 1 below. FIG. 12 is a cross-sectional view showing a configuration of the electrolyzed water generating device of Patent Document 1. As shown in the figure, the electrolytic cell of this electrolyzed water generating apparatus has a three-layer structure partitioned by a sheet-like diaphragm 1, and an electrolyte solution is supplied from a separately installed electrolyte solution tank 4 by a circulation pump 7. It is made to circulate and it electrolyzes by sending a direct current through the flat plate 3a and cathode plate 3b. The electrolytic cell is sealed, and the electrolyte solution is pressurized by the circulation pump 7.

This electrolyzed water generating device is an electrolyzed water generating device capable of efficiently generating a target product solution particularly when an electrolyte such as sodium chloride is added for electrolysis. In the electrolysis method of FIG. 12, since target ions dialyzed from the diaphragm come into contact with the electrode at a high concentration before being diffused into the bulk solution, efficient electrolysis can be performed.
Japanese Patent No. 3500173

  In the conventional electrolytic cell described above, the entire electrolytic cell must be disassembled when replacing the diaphragm or electrode, which is a consumable item, and this involves a very complicated operation and forced to completely stop the electrolysis operation. There was a point.

  In addition, in the electrolysis system in which a competitive reaction occurs on the electrode surface, for example, the oxygen generation reaction and the chlorine generation reaction in the anodic reaction of sodium chloride aqueous solution electrolysis, the physical properties of the anode solution, particularly the hydrogen ion concentration, are effective. In order to effectively adjust the balance of the chlorine concentration, it is necessary to devise various electrode surface catalytic capabilities, but it is difficult to adjust the physical properties by the electrode surface catalytic capability, and the life of the electrode catalyst is shortened. There is also a problem that it is not practical because problems such as

  Moreover, although the physical property balance of the generated water can be adjusted by adjusting the electrolysis current value, there is a problem in that the electrolysis efficiency is lowered and the consumable parts are prematurely deteriorated. Furthermore, a method of adjusting the concentration of the electrolyte solution supplied to the electrolytic cell is also conceivable. However, in this method as well, a decrease in electrolytic efficiency due to an increase in electrolysis voltage and a large waste of electrolyte due to the outflow of unelectrolyzed electrolyte can be avoided. There was also a problem of not.

  Also, the conventional electrolytic cell always has an electrode device frame due to its structure, and it is difficult to maintain a uniform electrolytic current density due to an edge current or the like with respect to the diaphragm or the electrode. There is also a problem that the life of the diaphragm and the electrode is adversely affected. .

  In addition, the electrolytic surface area of the anode and the cathode cannot be changed due to the structure, and there is a method in which a part of the electrode surface is coated with a non-conductive substance as a method of changing the electrode surface area ratio. This is only possible in the direction of decreasing the size, and there is also a problem that the electrolytic efficiency and the life of consumables are reduced.

  Furthermore, in conventional electrolytic cells, spacers must be used in order to keep the distance between the diaphragm and the electrode uniform. However, the spacer does not cause pressure loss of the supply water due to a flow path failure or presses the local diaphragm against the electrode. There was also the problem of making it happen. Furthermore, even if various attempts are made to contact the spacer with various spacers, it is necessary to pay close attention so that the intermediate tank pressure becomes the optimum positive pressure with respect to the pressure between both tanks. However, there is a problem in that there is a limitation in handling of the generated water or a complicated pressure balance adjusting mechanism must be provided.

  Furthermore, when the intermediate tank pressure is set to a positive pressure with respect to the both side tanks by the above-described method, the unresolved high-concentration electrolyte solution flows in due to the increased water flow rate due to deterioration of the consumable diaphragm. As a result, there is a problem that not only excessive loss of the electrolyte and predetermined physical properties of the generated water cannot be obtained, but also a serious accident may occur due to generation of harmful gas depending on the type of the electrolyte.

  The object of the present invention is to solve such problems and to provide an electrode device and an electrolytic cell that can be used in a device that continuously produces high-purity electrolyzed water by electrodialysis of a solution containing water or an electrolyte. In the point.

  The electrode device of the present invention includes a cylindrical electrode made of a corrosion-resistant metal having a conductive catalyst film supported on at least one of an outer surface and an inner surface, a cylindrical diaphragm covering the outside of the cylindrical electrode, and the diaphragm The main feature is that an inlet and an outlet for continuously flowing a liquid into the interior are provided.

  In the electrode device described above, the cylindrical electrode may have a number of holes on the surface. In the electrode device described above, the diaphragm may be a cylindrical diaphragm having a strength capable of sufficiently retaining the shape of the diaphragm itself. In the electrode device described above, a diaphragm having ion selective permeation performance may be used as the diaphragm.

  In the electrode device described above, both the inlet and the outlet may be provided at one end of the cylindrical diaphragm, and the other end of the cylindrical diaphragm may be sealed. . Moreover, the above-described electrode device may include means for adjusting the diameter of the cylindrical electrode.

  The electrolytic cell of the present invention uses the above-described electrode device as an anode electrode device and a cathode electrode device, fills the electrolytic solution in the bath and immerses the electrode device, and each electrode of the anode electrode device and the cathode electrode device The main feature is that a direct current is applied between them. In the electrolytic cell described above, the number ratio of the anode electrode device and the cathode electrode device may be a ratio other than 1: 1. In the electrolytic cell described above, a shielding plate may be provided between the anode electrode device and the cathode electrode device.

  The electrode device of the present invention has an independent structure with respect to the electrolytic cell casing, and is provided with pipes that serve as inlets and outlets at the end of the cylindrical diaphragm, and the electrode device is immersed in the electrolytic cell at the bottom. Or since it was set as the structure which supplies raw | natural water from an upper part, there exists an effect that the attachment or detachment to the electrolytic cell of each electrode apparatus becomes easy.

  In addition, the number and layout of the anode and cathode electrode devices can be freely designed based on the use and capacity of the electrolytic cell, and the physical property balance of the generated water can be adjusted without reducing the electrolytic efficiency. is there. In particular, there is an effect that it is possible to adjust the physical properties of the electrolysis solution generated from the anode electrode device in an electrolysis system in which a competitive reaction occurs on the electrode surface.

  In addition, by using a cylindrical diaphragm that has sufficient strength to hold the shape of the diaphragm itself, it is not necessary to pay attention to the pressure applied to the diaphragm. Electrolysis can be performed stably without using a spacer, and it is not necessary to apply pressure to the electrolyte solution chamber using a circulation pump as in the conventional example, and there is an effect that it is not necessary to seal the electrolytic cell.

  In addition, by using a cylindrical diaphragm with dimensional stability, the bias of the electrolysis current density with respect to the diaphragm and the electrode is reduced, and accidents that may occur when the diaphragm is deteriorated can be prevented. There is also an effect.

  The best mode for carrying out the invention will be described below with reference to the drawings.

  FIG. 1 is a plan view showing the configuration of the electrode device of Example 1 of the present invention. FIG. 2 is a cross-sectional view showing the configuration of the electrode device of Example 1 of the present invention. FIG. 3 is a longitudinal sectional view showing the configuration of the upper fixing member 10 of the electrode device according to the first embodiment of the present invention. In order to constitute an electrolytic cell, one or more electrode devices are used for the positive electrode and the negative electrode, respectively, and a total of two or more are used.

  The electrode device of Example 1 has a structure in which a cylindrical electrode 9a is arranged inside a cylindrical diaphragm 8 having sufficient dimensional stability by the diaphragm itself. The upper fixing member 10 and the lower fixing member 11 made of an insulating material provided above and below form an electrode device by holding the distance between the cylindrical diaphragm 8 and the cylindrical electrode 9a while maintaining a constant distance. Note that the distance between the cylindrical diaphragm 8 and the cylindrical electrode 9a varies depending on the application, and may be in close contact with almost no gap.

  The upper fixing member 10 and the lower fixing member 11 are fixed to the cylindrical diaphragm 8 and the cylindrical spacer 31 using an adhesive or the like, and the electrode 9 a is completely covered with the diaphragm 8.

  The water discharge port 13 a is made of a good-electricity metal having corrosion resistance such as titanium, and has a flange that engages with the upper fixing member 10. Further, this flange is fixed to the electrode 9a by welding or the like. The water discharge port 13a also serves as a power feeding portion (terminal) to the electrode 9a.

  The flange of the water discharge port 13a is fixed to the flange in the upper fixing member 10 by a fixing member 30 that is threaded. By removing the fixing member 30, the cylindrical diaphragm 8 and the cylindrical electrode 9a Can be separated.

  The lower fixing member 11 is provided with a threaded pipe 12, and the electrode device is installed in the electrolytic cell by fitting the pipe 12 into the screw hole of the electrolytic cell subjected to the corresponding threading. With this structure, the individual electrode devices can be easily detached from the electrolytic cell. In the lower fixing member 11, the lower part of the electrode 9 a is fixed, but is open, and the supplied raw water flowing in from the pipe 12 connected to the raw water supply pipe 5 can flow out to the inside and the outside of the electrode 9 a. is there.

  As the diaphragm 8, for example, polyethylene resin, polypropylene resin, vinyl chloride resin and terephthalate resin, ABS resin, epoxy resin, fluororesin, etc. are used as an aggregate, and polyvinylidene fluoride titanium oxide, sulfonic acid group, carboxylic acid group and various amines are used. A diaphragm coated with an organic solution having a group or the like can be used.

  As the diaphragm 8, you may employ | adopt what has ion exchange performance. As the cylindrical diaphragm 8 having ion exchange performance and sufficient dimensional stability by the diaphragm itself, for example, a product name “Edycore” (registered trademark) manufactured by Tokuyama Corporation can be adopted.

  As the cylindrical electrode 9a, for example, a so-called valve metal such as titanium, zirconium, niobium, ruthenium or the like having platinum, iridium oxide, titanium oxide, tantalum or the like supported on the surface of these alloys can be used as the base electrode. is there.

  By passing a direct current through the cylindrical electrode 9a, ions that have been dialyzed electrically from the diaphragm 8 give and receive electrons on the surface of the electrode. It reacts with the feed raw water and passes through the central part of the cylindrical electrode 9a and is discharged from the spout 13a attached to the upper fixing member 10 as the target product water.

  In the case of electrolysis, particularly when used in a system in which an oxidizing substance such as chlorine gas is generated on the anode when a sodium chloride solution is used, an insulating substance such as a passivation film on the outside of the cylindrical electrode 9a, that is, on the diaphragm side And reacting inside the cylindrical electrode 9a has an effect of reducing damage to the diaphragm 8.

  Therefore, the above-mentioned effect can be obtained by forming an insulating material outside the cylindrical electrode 9a of the electrode device for the anode and providing a large number of holes at intervals of several millimeters, for example. Further, in the electrolysis system in which bubbles are generated, the holes make it difficult for the bubbles to enter between the cylindrical diaphragm 8 and the cylindrical electrode 9a, which is effective in preventing an increase in electrolytic voltage.

  In the case of the above applications, the distance between the cylindrical diaphragm 8 and the cylindrical electrode 9a needs to be in close contact with almost no gap. Therefore, the cylindrical electrode 9a is provided with an electrode diameter adjusting means for adjusting the distance between the electrode 9a and the diaphragm 8 to the original design value when the electrode 9a is polished for maintenance work.

  As shown in FIG. 2, the cylindrical electrode 9a is provided with a gap provided with flanges 1 and 2 along the axial direction of the cylinder, and is engaged with a plurality of holes on the flange arranged in the axial direction of the electrode. The diameter of the electrode can be adjusted by the combined bolt 3 and nut 4. Although not shown, a hole for turning the bolt 3 from the outside is provided in the electrode 9a.

  This makes it possible to adjust the contact concentration of ions necessary for the target product water dialyzed from the diaphragm to the electrode by the dilution ratio in the supply water. In other words, the reaction rate can be adjusted in a competitive reaction system. Although the upper part of the electrode is fixed to the flange of the water discharge port 13a, there is no problem because the adjustment range of the diameter is slight.

  FIG. 4 is a cross-sectional view illustrating a configuration example of an electrolytic cell using the electrode device according to the first embodiment. The electrolytic bath 17 is filled with the electrolyte solution 17 to such an extent that the diaphragm of the electrode device is completely immersed, and is circulated / stirred by the circulation pump 7 connected to the electrolytic bath 17. Further, an electrolyte solution is supplied from a separately installed electrolyte solution tank 19 through a valve 18. The electrolytic cell 17 does not need to be sealed.

In the electrolytic cell 16, the two electrode devices A and B of Example 1 are installed. As the electrode device A for the anode and the electrode device B for the negative electrode, the above-described electrode devices having a large number of holes are used. The number of electrode devices A and B installed is arbitrary, and when a plurality of electrode devices A and B are installed, they are all connected in parallel.
In addition, as illustrated in FIG. 4, one or a plurality of shielding plates 20 may be provided between the electrode devices A and B. When providing a shielding plate corresponding to the electrode device, the shielding plate 20 is disposed in the vicinity of each electrode device as shown in the figure. By providing this shielding plate 20, it is possible to prevent a large electrolytic current from flowing locally to the diaphragm and the electrode, and to obtain a uniform electrolytic current density. Any metal, resin, or other material can be used as the shielding plate 20 as long as it has sufficient corrosion resistance to the electrolyte. Further, as the shape, a flat plate shape, a combination of flat plates, a semi-cylindrical shape or the like can be adopted. Moreover, you may use the punching board which provided many holes on the surface of the board. The shielding plate 20 preferably has a shape that does not hinder convection of the electrolytic solution.

  The raw water is supplied from the lower part to the electrode devices A and B via the raw water supply pipe 5 and the valves 15a and 15b. The opening degree of the valves 15a and 15b is adjusted so that the necessary physical properties and the amount of generated water can be obtained. In order to perform the electrolytic treatment, a direct current is supplied from the DC electric supply terminals 14a and 14b (the water discharge port 13 connected to the electrodes), and the insulation is connected to the water discharge ports 13 of the two electrode devices A and B. The produced water of each of the anode and the cathode is taken out from the tubes 6a and 6b.

  At this time, the liquid 17 to be electrodialyzed is a sodium chloride solution, and a diaphragm having anion selective dialysis performance is adopted as the diaphragm 8 of the electrode apparatus A. When a diaphragm having cation selective dialysis performance is used as the diaphragm 8, strongly acidic water containing no more sodium than the amount contained in the feed water from 6a is more chloride ion than 6b. Strong alkaline water that does not contain more than the amount contained in the feed water is continuously obtained.

  FIG. 5 is a cross-sectional view showing another configuration example of the electrolytic cell using the electrode device of the first embodiment. In this modification, one electrode device for negative electrode is arranged at the center of a cylindrical electrolytic cell 16, and eight electrode devices for positive electrode are arranged around it, and the other configuration is the same as that of FIG. Thus, by making the number of electrode devices different for the positive electrode and the negative electrode, it is generally possible to ease the electrolysis conditions of the anode having a shorter life than the cathode in electrolytic solution electrolysis.

  Further, by reducing the anode current density, for example, in the electrolytic competitive reaction on the anode surface in sodium chloride solution electrolysis, the following reactions (2) and (3) required for producing a hypochlorous acid solution are made efficient. Can be advanced.

(1) 2H ₂ O → O ₂ + 4H ⁺ + 4e ⁻
(2) 2Cl ⁻ → Cl ₂ + 2e ⁻
(3) Cl ₂ + H ₂ O → HClO + HCl

  Next, a second embodiment of the electrode device will be described. FIG. 6 is a plan view showing the configuration of the electrode device of Example 2 of the present invention. Moreover, FIG. 7 is sectional drawing which shows the structure of the electrode apparatus of Example 2 of this invention. Further, FIG. 8 is a longitudinal sectional view showing a configuration of the upper fixing member 10 of the electrode device according to the second embodiment of the present invention.

  The material of the electrode device of the second embodiment can be the same as that of the first embodiment. However, there is no hole in the electrode 9b, the supply raw water flows in from the inlet 13b attached to the upper part of the electrode 9b that also serves as a power feeding part, flows downward through the inside of the cylindrical electrode 9b, and is fixed to the lower part. It flows into the gap between the electrode 9b and the cylindrical diaphragm 8 from the gap provided between the member 11 and the cylindrical electrode 9b, and dissolves the dialyzed ions and the substance that has received and transferred electrons on the electrode. The water is discharged from the water discharge port 13 c of the upper fixing member 10.

  FIG. 9 is a cross-sectional view illustrating a configuration example of an electrolytic cell using the electrode device of the second embodiment. 4 differs from the electrolytic cell of FIG. 4 in that raw water is supplied from the inlet 13b above the electrode devices C and D via the raw water supply pipe 5 and valves 15a and 15b. The point is that water generated from each of the anode and the cathode is taken out from the insulating tubes 6 a and 6 b connected to the water discharge port 13.

  When the structure of the second embodiment is used, it is not necessary to fix the lower fixing member 11 to the electrolytic cell and to connect the inlet, and it is only necessary to immerse the electrode device in the electrolytic cell filled with the electrolyte solution. The manufacture, maintenance, and management of the electrolyzer can be simplified.

  FIG. 10 is a cross-sectional view illustrating another configuration example of the electrolytic cell using the electrode device according to the second embodiment. In this electrolytic cell, a plurality of electrode devices of Example 2 are alternately arranged in a line for the positive electrode and the negative electrode. Note that a plurality of rows of the arrangement shown in FIG. 10 may be arranged in the electrolytic cell. In this case, the positions of the positive electrode device and the negative electrode device are exchanged every other row so that the positive electrode device and the negative electrode device are arranged adjacent to each other between the rows.

FIG. 11 is a cross-sectional view showing another example of the electrolytic cell using the electrode device of Example 2. In this example, in the electrolytic cell of the second embodiment, the electrolytic solution tank is removed and the electrolytic cell 16 itself is also used as the electrolytic solution tank. The electrolyte and water that are reduced as a result of operation are directly fed into the electrolytic cell 16. Stirring is also performed not by the circulation pump but by the blade 41 rotated by the motor 40. Air may be fed into the tank and stirred by bubbles.
Furthermore, an example in which stirring means such as blades and bubbles are not used in this electrolytic cell is also conceivable. In the electrolytic cell of the conventional example, if the circulation means is not used, the electrolyte staying in the intermediate electrolyte solution chamber is gradually consumed, and electrolysis becomes impossible due to the increase in the electrolysis voltage accompanying the decrease in electrical conductivity. However, as shown in FIG. 11, the electrode device is immersed in an electrolyte solution in an electrolytic cell having a certain capacity, so that the electrolyte is supplied to the electrode by concentration diffusion. The electrolyte is more smoothly supplied to the electrode by convection.

  Although the embodiments have been described above, the following modifications may be considered in the present invention. In the first embodiment, the configuration in which the raw water is supplied from the lower part of the electrode device has been disclosed. It is also possible to provide a pipe penetrating through the pipe, and supply raw water from the upper part to the lower part through this pipe so that the gap between the pipe and the electrode rises. Or it is good also as a U-shaped electrode apparatus by connecting two electrode apparatuses of the structure of Example 1 in the lower part. In this way, it is not necessary to make a hole in the electrolytic cell and fix the electrode device.

  As another example of the electrolytic cell configuration, an electrolytic cell structure including two concentric cylindrical electrodes having different diameters is also possible. In this case, for example, a negative electrode cylindrical electrode, a first cylindrical diaphragm, a second cylindrical diaphragm, and an anode cylindrical electrode are sequentially formed from the inside, and a cylinder that serves as an electrolytic cell further outside the anode cylindrical electrode. A container. It is also possible that the anode cylindrical electrode also serves as an electrolytic cell container.

  The electrolytic cell of the present invention can be industrially mass-produced, and as a large-scale plant apparatus in the agricultural field where adverse effects such as salt damage are worried because excess undecomposed electrolyte is hardly contained in the generated water. Is also available.

It is a top view which shows the structure of the electrode apparatus of Example 1 of this invention. It is a cross-sectional view which shows the structure of the electrode apparatus of Example 1 of this invention. FIG. 3 is a longitudinal sectional view illustrating a configuration of an upper fixing member of the electrode device according to the first embodiment. FIG. 3 is a cross-sectional view showing a configuration example of an electrolytic cell using the electrode device of Example 1. 6 is a cross-sectional view showing another example of an electrolytic cell using the electrode device of Example 1. FIG. It is a top view which shows the structure of the electrode apparatus of Example 2 of this invention. It is sectional drawing which shows the structure of the electrode apparatus of Example 2 of this invention. It is a longitudinal cross-sectional view which shows the structure of the upper fixing member of the electrode apparatus of Example 2. It is sectional drawing which shows the structural example of the electrolytic cell which uses the electrode apparatus of Example 2. FIG. 6 is a cross-sectional view showing another example of an electrolytic cell using the electrode device of Example 2. FIG. 6 is a cross-sectional view showing another example of an electrolytic cell using the electrode device of Example 2. FIG. It is sectional drawing which shows the structure of the electrolyzed water generating apparatus of patent document 1.

Explanation of symbols

8 ... Diaphragm 9a, 9b ... Electrode 10 ... Upper fixing member 11 ... Lower fixing member 12 ... Pipes 13a, 13c ... Water outlet 13b ... Inlet 14 ... DC electric supply terminal 16 ... Electrolyzer

Claims (9)

A cylindrical electrode made of a corrosion-resistant metal having a conductive catalyst coating supported on at least one of an outer surface and an inner surface;
A cylindrical diaphragm covering the outside of the cylindrical electrode;
An electrode device comprising an inlet and an outlet for continuously flowing a liquid into the diaphragm.   The electrode device according to claim 1, wherein the cylindrical electrode has a large number of holes on a surface thereof.   2. The electrode device according to claim 1, wherein the diaphragm is a cylindrical diaphragm having a strength capable of sufficiently retaining the shape of the diaphragm itself.   The electrode device according to claim 1, wherein a diaphragm having ion selective permeation performance is used as the diaphragm.   2. The inflow port and the discharge port are both provided at one end of a cylindrical diaphragm, and the other end of the cylindrical diaphragm is sealed. Electrode device.   2. The electrode device according to claim 1, further comprising means for adjusting a diameter of the cylindrical electrode.   The electrode device according to any one of claims 1 to 6 is used as an anode electrode device and a cathode electrode device, an electrolytic solution is filled in a tank and the electrode device is immersed, and the anode electrode device and the cathode electrode device An electrolysis cell for electrodialysis decomposition, wherein a direct current is applied between the electrodes.   The electrolytic cell for electrodialysis decomposition according to claim 7, wherein the number ratio of the anode electrode device and the cathode electrode device is a ratio other than 1: 1. The electrolysis cell for electrodialysis decomposition according to claim 7, wherein a shielding plate is provided between the anode electrode device and the cathode electrode device.

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