JPH0533176A - Electrode body and application thereof - Google Patents

Abstract

PURPOSE:To develop the electrode body having good electric power efficiency and utilization rate of a floor surface by adhering electrode plates having good gas permeability as electrodes to be used for the electrolysis of water via a thin film having fine pores. CONSTITUTION:Stainless conductive materials, such as Ni plates, stainless steel plates and platinum plates, are used as the electrode body 8 consisting of the cathode plate 9 and anode plate 9 to be used at the time of drawing gaseous hydrogen and gaseous oxygen by electrolyzing water 2 and the electrode body has macroscopic transmission holes 11 easily separating the gaseous hydrogen and gaseous oxygen of the components formed by the electrolysis from the electrode surface. Further, the thin film 10 which of chemically stable 'TeflonAngstrom ' or 'SaranAngstrom ' and has the fine pores at <=25micron thickness to allow the easy passage of the water of the raw material is interposed between the two electrode plates 9 and 9. The water of the raw material easily passes this thin film 10 but the gaseous hydrogen and gaseous oxygen generated by the electrolysis easily separate from the two electrode plates 9, 9 and are easily separated and recovered from respective gas taking out ports 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode body used for electrolysis of water and the like and its use.

[0002]

2. Description of the Related Art In recent years, whether or not the environment is friendly has become an important factor for judging the suitability of things.

In terms of energy as well, "clean energy" such as methanol and hydrogen, which are friendly to the global environment, is being reviewed, and at present, how to produce such clean energy in large quantities and at low cost is a problem. .

Of these, for hydrogen, a method of processing fossil fuels such as natural gas and coal and a method of electrolyzing water are known. The former method has the advantage that a large amount of hydrogen can be produced, but on the other hand, the production equipment tends to be large-scale, and the purity of the obtained hydrogen is low, and a large amount of carbon dioxide is produced as a by-product during the production, which results in the earth. There is a problem that it easily pollutes the environment. The latter method has the advantage that a high-purity product can be obtained with a simple manufacturing apparatus, but it consumes relatively large amount of power, and thus has a problem that the product cost is likely to increase. However, at present, the development of inexpensive and clean power generation means such as nuclear power generation and solar thermal power generation is earnestly underway, and it is expected that hydrogen production by electrolysis of water will become the mainstream in the future.

Considering the electrolysis system of water, therefore, a typical conventional electrolytic cell normally has a water supply port for supplying water as a substance to be electrolyzed and hydrogen gas and oxygen gas generated by electrolysis. With a certain gap in the reaction tank provided with a gas collection port for separating and collecting and, for example, a pair of electrodes made of a non-corrosive conductive material such as nickel or a nickel-plated iron plate are opposed to each other, and electrolysis is performed. In order to prevent the mixture of hydrogen gas and oxygen gas generated by, a diaphragm made of asbestos cloth is attached between the pair of electrodes. Therefore, in the conventional electrolytic cell, the gap between the electrodes has to be relatively large, and thus there is a limit in improving the power efficiency and the floor surface utilization efficiency. In addition, bubbles are generated on the electrodes during electrolysis, and the diaphragm itself acts as an electric resistance, which is one of the causes of lowering the power efficiency. Although it has been known that the power efficiency increases when the electrodes are brought close to each other, when the electrodes are brought close to each other, bubbles generated on the electrodes increase the electric resistance between the electrodes, which is rather a reverse effect in many cases. It was

[0006]

In view of the above situation, an object of the present invention is to provide an electrode body having high power efficiency and high floor utilization efficiency.

A further object of the present invention is to provide a compact electrolytic cell having high power efficiency.

[0008]

Means for Solving the Problems As a result of intensive studies by the present inventor, a thin film having a large number of microscopic holes through which a substance to be electrolyzed, such as water, can permeate is easily removed from generated bubbles. The electrode body sandwiched between a pair of electrode plates having a large number of macroscopic holes is usually about 80% or more, desirably about 82% or more, and the power efficiency is extremely high. It has been found that since the plate is integrally formed, the utilization efficiency of the floor surface is significantly improved.

That is, according to the present invention, an electrode body is formed by sandwiching a thin film having a large number of microscopic holes through which a substance to be electrolyzed can be sandwiched between a pair of electrode plates having a large number of macroscopic holes. Is related to the structure of.

Further, according to the present invention, an electrode body is formed by sandwiching a thin film having a large number of microscopic holes through which a substance to be electrolyzed can be sandwiched between a pair of electrode plates having a large number of macroscopic holes. The gist is the structure of an electrolytic cell containing

[0011]

According to the present invention, since the pair of electrode plates are opposed to each other substantially only by the thickness of the thin film, the electric resistance between the electrode plates during energization becomes low.

Moreover, since a large number of macroscopic through holes are formed in the pair of electrode plates, the generated bubbles can be easily separated from the electrode plates.

Next, the present invention will be described based on the illustrated embodiments.

【Example】

FIG. 1 is a vertical side view of an embodiment according to the present invention.

In the figure, reference numeral 1 is a reaction tank for containing a substance 2 to be electrolyzed, such as water, for electrolysis. On the upper wall of the reaction tank 1, a hydrogen gas outlet 3 for taking out hydrogen gas generated by electrolysis to the outside of the reaction tank 1 and oxygen gas are provided in the reaction tank 1.
An anode terminal 5 and a cathode terminal 6 are provided along with an oxygen gas outlet 4 for taking out to the outside. These anode terminals 5
The cathode terminal 6 and the cathode terminal 6 are connected to the anode and the cathode of the DC power source, respectively, via a switch, a voltage control circuit, a current control circuit, etc., if necessary. On the side wall of the reaction tank 1, the reaction tank 1
A water supply port 7 for supplying a substance to be electrolyzed such as water is provided therein. If necessary, caustic alkali such as caustic potash or caustic soda is added to the substance to be electrolyzed 2, or a neutral surfactant or silicone oil is further added to further promote the removal of generated bubbles. You may add humectants, such as.

Reference numeral 8 is an electrode body, which is normally mounted vertically in the substantially central portion of the reaction tank 1. The electrode body 8 is configured by sandwiching the thin film 10 from both sides by a pair of electrode plates 9, 9, and the peripheral green part of the thin film 10 is fixed along the inner wall of the reaction tank 1 to partition the inside of the reaction tank 1. There is.

The pair of electrode plates 9 and 9 are usually formed on a wide surface of a non-corrosive conductive material such as nickel, nickel plating, nickel steel, cobalt plating, stainless steel, silver, platinum and carbon formed in a plate shape. A large number of macroscopic through holes are formed so that bubbles generated by electrolysis can be easily detached. The material of the electrode plates 9 and 9 is not limited to metal, and even if the electrode plates 9 and 9 are non-conductive themselves such as synthetic resin and glass, they are used as the electrode plates 9 and 9 when imparting ion exchange capability. be able to.

The thin film 10 is chemically and physically stable when used in electrolysis. For example, Teflon, saran, polyvinyl, polyvinyl chloride, polystyrene, nylon, urea formaldehyde resin, phenol formaldehyde resin, melamine formaldehyde resin, Synthetic resins such as alkyd resin and organic silicon resin, cellulose, pullulan ester, pullulan ether, polysaccharides such as paper and cloth, rubber,
A non-conductive material such as glass or ceramic is formed into a film or sheet shape, and during electrolysis, the substance to be electrolyzed 2 can permeate, but a large number of microscopic holes through which the generated gas cannot substantially permeate. Is provided and configured.

The above situation is shown in FIG.

As shown in FIG. 2, a large number of macroscopic through holes 11 are bored in the pair of electrode plates 9 and 9 so that bubbles generated by electrolysis can be easily released. This macroscopic through hole 1
There is no particular limitation on the shape of 1, for example, a square, a rectangle,
A suitable shape such as a rhombus, a circle, an ellipse, a star, or a strip may be used. The diameter of the macroscopic through hole 11 allows the generated bubbles to be easily desorbed without substantially disturbing the current distribution between the electrodes during electrolysis, and the electrode body 8 itself can maintain the desired mechanical strength. It should be about. Depending on the size of the electrode plates 9, 9, it is usually about 0.01 to 10 cm, preferably about 0.05 to 5 cm. This occurs when the peripheral edge of the opening of the macroscopic through hole 11 is rounded and the electrode body 8 is vertically mounted in the reaction tank 1 so that the peripheral edge of the opening forms an upward angle with respect to the horizontal plane. Due to the buoyancy of the bubbles, the electrode plate 9,
It is convenient because it helps to get out of 9. When forming the electrode body 8 in a cylindrical shape, a wire mesh electrode plate is convenient. As shown in FIG. 1, the electrode plates 9 and 9 are connected to the anode terminal 5 or the cathode terminal 6 via lead wires 12 and 12.

It is desirable that the thin film 10 be as thin as possible within a range that can be practically used or manufactured, and it is usually less than about 25 microns, preferably about 1 to 10 microns. The diameter of the microscopic holes depends on the type of the substance to be electrolyzed and the current density, but when the substance to be electrolyzed is water, it is usually less than about 10 microns.

Although FIG. 1 shows an example in which one electrode body is attached to one reaction tank, the present invention is not limited to such an embodiment. For example, as shown in FIG. It goes without saying that the electrode body may be formed in a cylindrical shape, or two or more electrode bodies may be attached to one reaction tank and the electrode bodies may be connected in series and / or in parallel.

Next, the operation of the electrolytic cell shown in FIG. 1 will be described based on experimental examples.

[Experimental example]

Highly pure hydrogen gas was prepared by electrolyzing water using the electrolytic cell shown in FIG.

A pair of platinum electrode plates 9 provided with a large number of macroscopic through holes 11 having a diameter of about 1 mm at appropriate intervals.
9 (10 cm in length, 4 cm in width, 1 mm in thickness) and a thin film 10 made of Teflon having a thickness of about 10 μm (diameter of microscopic through holes of about 5 μm) constitute the electrode body 8. It was fixed vertically in the approximate center of the reaction tank 1.
The surrounding green of each opening of the macroscopic through hole 11 was rounded so that the generated gas could be easily released. The anode terminal 5 and the cathode terminal 6 were connected to the positive output terminal and the negative output terminal of the control DC power supply device via a precision power meter, respectively.

Pure water in which 30% caustic potash was dissolved as the substance to be electrolyzed 2 was stored in the reaction tank 1, the temperature in the reaction tank 1 was maintained at about 50 ° C., and pure water preheated to about 50 ° C. was supplied. While appropriately replenishing through the mouth 7, 2.0 V DC was applied between the pair of electrode plates 9 to electrolyze for 5 hours. During the electrolysis, the amount of hydrogen gas generated and the power consumption were measured at regular intervals, and the surroundings of the electrode body 8 were visually observed.

Separately, water was electrolyzed in the same manner except that the electrode body 8 having no macroscopic through hole 11 was used.
It was used as a control system.

As a result, it was found that the power efficiency when electrolyzing water using the electrolytic cell of the present invention was extremely high, reaching about 84%. Moreover, this high power efficiency was substantially constant throughout the electrolysis, and the generated bubbles were quickly separated from the electrode plates 9, 9.

On the other hand, the control system had about 8
Although it showed a relatively high power efficiency of 3%, it decreased sharply after about 1 minute, and the power efficiency after 5 hours was about 67%. When the surroundings of the electrode body 8 were visually observed, remarkable air bubble adhesion to the surfaces of the electrode plates 9 and 9 was observed before and after the decrease in power efficiency.

As described above, even the control system achieved a high power efficiency of about 82%. The structure of the present invention in which the thin film 10 is sandwiched between the pair of electrode plates 9 and 9 is extremely effective in improving the power efficiency. It proves to be effective. Also,
The fact that the electrode body of the present invention in which the pair of electrode plates 9 and 9 are provided with the macroscopic through-holes 11 consistently achieves a high power efficiency of approximately 84%, is that the macroscopic through-holes 11 have bubbles. This proves that it is extremely effective in preventing a decrease in power efficiency due to adhesion. The purity of the collected hydrogen gas was analyzed by gas chromatography.
The purity was extremely high at 9% or more.

[0031]

As described above, the electrode body of the present invention comprises a pair of electrodes in which a thin film having a large number of microscopic holes through which a substance to be electrolyzed can be formed and a large number of macroscopic holes are formed. Since it is sandwiched between the plates, the power efficiency is good and the floor utilization efficiency can be increased.

Furthermore, according to the present invention, an electrolyzer having high power efficiency can be formed compactly, and can be advantageously used for electrolysis of various substances to be electrolyzed including water. Therefore, the electrode body and the electrolytic cell according to the present invention can be advantageously used not only for hydrogen production on a factory scale but also for preparing high-quality hydrogen on a relatively small scale such as in a laboratory. .

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an electrolytic cell using an electrode body of the present invention.

FIG. 2 is a vertical cross-sectional side view of the electrode body of the present invention with a part thereof omitted.

FIG. 3 is a vertical plan view showing another embodiment of the electrode body according to the present invention.

[Explanation of sign]

1 reaction tank 2 Electrolyte 3 Hydrogen gas outlet 4 Oxygen gas outlet 5 Anode terminal 6 cathode terminal 7 water inlet 8 electrode body 9 electrode plate 10 thin film 11 Macroscopic through holes 12 lead wire

Claims (5)

[Claims] 1. An electrode body comprising a thin film having a large number of microscopic holes through which a substance to be electrolyzed can be sandwiched between a pair of electrode plates having a large number of macroscopic holes. 2. The electrode body of claim 1, wherein the thin film has a thickness of less than about 25 microns. 3. The substance to be electrolyzed is water, and the bubbles generated are hydrogen gas and oxygen gas.
Or the electrode body according to 2. 4. An electrode body comprising a thin film having a large number of microscopic holes through which a substance to be electrolyzed can be sandwiched between a pair of electrode plates having a large number of macroscopic holes formed therein. Electrolyzer. 5. The electrolytic cell according to claim 4, wherein the substance to be electrolyzed is water and the bubbles are hydrogen gas and oxygen gas.