JPS608309B2 - water electrolysis device - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in miniaturization of electrolyzers.

More specifically, the present invention relates to a method of shortening the distance between electrodes by suppressing the generation of bubbles on the electrode surface by extracting gas generated by electrolysis into the electrode. Electrolyzers are broadly divided into monopolar and bipolar types, but in either case, a diaphragm is installed between the electrodes, and gas is taken out from a gas chamber connected to the diaphragm.

In the case of such a structure, if the current efficiency is to be increased and at the same time the device is to be miniaturized, it is possible to consider means of lowering the resistance between the electrodes. Increasing the area of the electrodes as a method of lowering the resistance between the electrodes increases the size of the electrolytic cell, which not only goes against the trend of miniaturizing the device but also increases equipment costs. Therefore, a method of shortening the distance between the electrodes has been considered, but this increases the risk of short circuit between the electrodes and, in particular, increases the content of bubbles generated by electrolysis, which increases the resistance between the electrodes, making it less effective. No. If a rough diaphragm is used to smoothly remove bubbles and reduce electrical resistance, gases will mix with each other through the diaphragm, resulting in a decrease in gas purity. Furthermore, the risk of short circuit between the electrodes also increases.
The inventor of the present invention solved the above-mentioned defects of the follower device by discovering a new method for shortening the distance between the electrodes. The present invention is a device having a function of quickly removing gas generated by electrolysis from the electrolytic field. That is, the electrolyzer has a structure in which a porous electrode having a hollow interior is used so that gas generated on the electrode surface is taken out through the hollow inside the electrode. Next, water electrolysis will be explained in more detail using the drawings as an example.

FIG. 1 is a schematic diagram showing an example of the present invention. 1 is an electrolytic tank, 2 is a porous negative electrode, 3 is a porous positive electrode, 4 is a porous diaphragm installed between the electrodes, 5 is a lid of the electrolytic tank, 6 is a 20% caustic soda electrolyte, and 7 is a porous In the internal hollow part of the electrode, 8 is a hydrogen gas extraction passage and a negative potential supply body, 9 is an oxygen gas extraction passage and a positive potential supply body, and 10 is a water supply passage.

FIG. 2 is a schematic diagram showing a conventional method. 1 is an electrolytic tank, 2 is a negative electrode, 3 is a positive electrode, 4 is a porous diaphragm installed between the electrodes, 5 is a lid of the electrolytic tank, 6 and 7 are 20% caustic soda electrolyte, 8 is hydrogen Gas outlet, 9 is oxygen gas outlet, 10
11 is a negative potential supply path, 11 is a positive potential supply path, and 12 is a water supply port.

When electrolysis starts in the device shown in Figure 2, hydrogen gas is generated on the surface of the negative electrode 2, forms bubbles, rises through 6 between the negative electrode 2 and the diaphragm 4, and reaches the outlet 8. Similarly, oxygen gas rises through 7 and heads toward the exit at 9. Therefore, if the gap between 6 and 7 is narrowed in an attempt to lower the electrical resistance, the proportion of gas in the electrolytic solution in the gap increases, and the inter-electrode resistance increases, making the effect less effective. Similarly, if the diaphragm is made to have a rough structure in order to lower the electrical resistance, the hydrogen gas bubbles at 6 and the oxygen gas bubbles at 7 will mix with each other, reducing the purity of the gas. . In the present invention, as shown in FIG. 1, the electrode is porous and has a hollow portion 7 therein, which communicates with gas extraction passages 8 and 9.

Air bubbles on the electrode surface generated by electrolysis are pushed through the gap in the porous electrode 2 into the internal hollow part 7, and air bubbles no longer float between the electrode and the corneal membrane. Therefore, the diaphragm 4 installed between the electrodes only needs to be careful about short-circuiting between the electrodes and smooth supply of the electrolyte, without worrying about impurity due to the mixing of gases generated at both the positive and negative electrodes. It became possible to shorten the distance between the electrodes. That is, a material such as a coarse nonwoven fabric can be used as the diaphragm, and it is also possible to use the diaphragm in direct contact with the electrode. Furthermore, if the operation is performed ideally, there may be no need to use a diaphragm. In actual operation, it is preferable to make the pressure on the electrolyte side higher than on the hollow part of the electrode. The gas generated by increasing the height is smoothly introduced into the electrode. Examples of the shape of the porous electrode, which is a feature of the present invention, include flat plate shapes with various internal hollow parts as shown in cross-sectional views in FIGS. 3 to 5, and those shown in FIGS. A porous conductive hollow fiber or pipe shape as shown in the cross-sectional view is used.

The method for making the electrode porous may be similar to the general manufacturing method for Akatsuki metal or porous carbon, and it is also possible to process it using a porous body of metal or carbon. Therefore,
Sintered powders, metal non-woven fabrics, metal-bonded materials, and methods for sintering polymers containing metal powders as shown in Tokubatsu 1989-99122, and carbon material raw materials. It can also be obtained by mixing glass powder with pitch, PVC, polyacrylonitrile polymer, cellulose, or other polymeric materials, subjecting it to flameproofing and carbonization, and then firing it at a temperature that vaporizes silicon carbide. I can do it.

[Brief explanation of the drawing]

FIG. 1 shows an example of a device according to the invention. FIG. 2 shows an example of a conventional device. 3, 4, and 5 show examples of cross sections of flat electrodes used in the present invention. FIG. 6 shows an example of a cross section of a hollow fiber or pipe electrode. 1st
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A water electrolyzer having an electrolytic cell, positive and negative electrodes, a positive and negative potential supplier to each electrode, a water supply port, and a generated gas outlet, which has a hollow part connected to the gas outlet, and has a hollow part connected to the outside. The positive and negative electrodes are porous electrodes with many pores forming gas flow paths on the surface, and the gas generated on the electrode surface during electrolysis passes through the pores of the electrode and reaches the hollow part, and further electrolysis occurs. 1. A water electrolysis device characterized by having a pressure reduction or suction means for taking out the water out of the tank.