JP3748765B2 - Electrolytic gas generation method and electrolytic gas generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrolytic gas generation method and an electrolytic gas generation device that generate ozone gas by electrolysis, and more specifically, an electrolytic gas generation method that makes ozone generation more stable and generates high-concentration ozone gas, and The present invention relates to an electrolytic gas generator.
[0002]
[Prior art]
The idea of generating ozone gas by electrolyzing water is old and has been performed for more than 100 years. In the old days, it was a solution electrolysis method that generates ozone by electrolyzing a liquid containing an anion having a high electronegativity, but with the recent development of solid polymer electrolytes, water electrolysis using polymer solid electrolytes Ozone generators have been manufactured and marketed.
[0003]
The so-called zero-gap water electrolysis, which uses a perfluorocarbon sulfonic acid cation exchange membrane as a solid electrolyte and has anodes and cathodes in close contact with each other, is simple in structure and easy to handle, and has no corrosive properties other than ozone gas Therefore, it has come to account for most of the recent water electrolysis ozone generation.
[0004]
The ozone gas concentration is around 20%, and the other is oxygen gas containing saturated water vapor, which is a mixed gas of ozone and oxygen containing almost no impurities.
[0005]
Therefore, the use of ozone is also widespread in the field of sterilization and recently in the field of semiconductor cleaning. Compared to the silent discharge method, which uses ozone as a raw material and generates ozone by applying high-frequency high voltage, there is a drawback that the power consumption is somewhat higher, but because the ozone gas concentration is high, the solubility in ultrapure water is high and the purity is high. There was an advantage that high concentration ozone could be easily manufactured.
[0006]
However, miniaturization is required as the density of semiconductors increases, and the accuracy of cleaning has been particularly required in recent years.
[0007]
In addition, the quality of ultrapure water has been improved along with miniaturization, and ultrapure water containing no metal or organic matter has been generated and used.
[0008]
In the generation of ozone by electrolysis, changes in the quality of pure water as a raw material have affected ozone gas generation, and the electrolysis voltage has changed and the ozone gas concentration has fluctuated.
[0009]
In particular, since fluctuations in the ozone gas concentration cause instability of cleaning and cause cleaning failure, there is a strong demand for stable ozone gas concentration.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to provide an electrolytic gas generation method and an electrolytic gas generation device for solving the problems of the above-described conventional technology and obtaining high-concentration ozone that is continuous and always stable for a long period of time. To do.
[0011]
[Means for Solving the Problems]
In the electrolytic gas generation method of the present invention, a porous anode material and a cathode material are closely arranged on both sides of an ion exchange membrane, and the ion exchange membrane is electrolyzed as a solid electrolyte, so that ozone gas and oxygen are introduced from the anode side. In the electrolytic gas generation method for producing gas and hydrogen gas from the cathode side, ozone gas is brought into contact with pure water supplied to the anode side, and the pure water is supplied as ozone water.
[0012]
In the electrolytic gas generator of the present invention, a porous anode material and a cathode material are arranged in close contact with both sides of an ion exchange membrane, and the ion exchange membrane is electrolyzed as a solid electrolyte, whereby ozone gas and oxygen are introduced from the anode side. In an electrolytic gas generator for producing hydrogen gas from a cathode side, ozone gas is brought into contact with pure water supplied to the anode side so that the pure water becomes ozone water.
[0013]
Hereinafter, the present invention will be described in detail.
[0014]
For example, porous anode material and cathode material are placed in close contact on both sides, and the ion exchange membrane is electrolyzed as a solid electrolyte to produce ozone gas and oxygen gas from the anode side, and hydrogen gas from the cathode side. When the electrolysis gas generator was supplied with 18.25 MΩ ultra-pure water containing no metal or organic matter and electrolyzed, the generation efficiency of ozone gas was only 10%.
[0015]
In the present invention, a porous anode material and a cathode material are closely arranged on both sides, and the ion exchange membrane is electrolyzed as a solid electrolyte, so that ozone gas and oxygen gas are supplied from the anode side, and hydrogen gas is supplied from the cathode side. In the electrolytic gas generator that manufactures, the ozone gas is brought into contact with the pure water supplied to the anode side, and the pure water becomes ozone water, thereby suppressing fluctuations in the generated ozone gas concentration and enabling stable ozone generation. became.
[0016]
Next, detailed conditions regarding the electrolytic gas generator according to the present invention will be described.
[0017]
In the generation of electrolytic gas that produces ozone gas and oxygen gas from the anode side and hydrogen gas from the cathode side, gas-liquid gas separation is required to separate the raw water and product gas on the anode side. The ozone gas concentration is determined by the ozone concentration of the water being separated. The source of this water was supplied pure water, and it was no exaggeration to say that the ozone gas concentration depends on the metal and impurities in this pure water.
[0018]
Here, the pure water means that the specific resistance of normal tap water is 1/100 to 1/200 MΩ, but the purity is 1 MΩ or more by removing metal contamination therein.
[0019]
In the electrolytic gas generator, pure water at the installation site is used as raw material pure water. Since this pure water is not generated for ozone generation but generated for cleaning, the specification is a specification for satisfying the cleaning.
[0020]
In cleaning that does not require much metal or organic removal, the quality of pure water is not very good. In such a case, in general, no treatment is performed on the organic matter.
[0021]
When such pure water is supplied to the anode side, ozone is consumed by the organic matter in the pure water and the ozone gas concentration does not increase.
[0022]
On the other hand, especially as in recent semiconductor manufacturing, the miniaturization of semiconductors has progressed, and the quality of pure water has improved accordingly, and ultra-pure water containing no metal or organic matter is generated and used. It has become to.
[0023]
In the case of such ultra-pure water, a system for treating and circulating a large amount of pure water and using a small amount of ultra-pure water is generally used as a method to completely eliminate organic substances. It is often done.
[0024]
For such treatment, UV sterilization is generally used, and ultrapure water is inevitably subjected to UV sterilization several times. By performing the UV sterilization treatment, hydrogen peroxide remains in the ultrapure water.
[0025]
When such ultrapure water is supplied to the anode side, ozone is consumed by residual hydrogen peroxide in the ultrapure water and the ozone gas concentration does not increase.
[0026]
Thus, in the conventional electrolytic ozone generation, the ozone generation in electrolysis is delicately influenced by components other than metal contamination in pure water.
[0027]
In the present invention, a simple, stable and high-concentration ozone gas is generated by a mechanism in which pure water supplied to the anode side comes into contact with the ozone gas so that the pure water becomes ozone water. Prepare and use ozone water and supply to the anode side.
[0028]
In order for pure water to come into contact with ozone gas to become ozone water, in the case of pure water containing the organic matter described above, the organic matter is decomposed with ozone gas before being supplied as ozone water. The generated ozone is not consumed by organic substances in pure water. In the case of pure water containing hydrogen peroxide, the hydrogen peroxide in the pure water is oxidized by ozone gas (H ₂ O ₂ + O ₃ = H ₂ O + 2O ₂ ) to become water, and further to ozone water. Since it is supplied to the anode side, ozone generated at the anode is not consumed by hydrogen peroxide in pure water.
[0029]
The ozone gas that comes into contact with the pure water supplied to the anode side before the supply may be the generated ozone gas, but from an economic point of view, it is possible to use ozone gas that has been used once and processed, so-called exhaust ozone gas. desirable. In addition, it goes without saying that the amount of ozone gas is more than the amount that decomposes organic substances and oxidizes hydrogen peroxide, but in the case of hydrogen peroxide, it may catalyze ozone. It is desirable to supply more than 10 times the calculated value.
[0030]
At the same time, the amount of ozone gas contacting the pure water supplied to the anode side before supply may be determined automatically by measuring the amount of TOC or hydrogen peroxide and calculating it. Similarly, a mechanism capable of detecting the ozone concentration in the pure water after contact with the ozone gas may be provided, and the ozone gas amount may be automatically determined using the ozone concentration as an index.
[0031]
Furthermore, there are various methods for contacting the pure water supplied to the anode side with the ozone gas that comes into contact before the supply. In general, a method of mixing ozone gas into the pure water flow using an ejector or a static mixer. A method in which ozone gas is diffused from a diffuser plate to dissolve ozone gas into pure water, a method in which pure water is introduced into one side by a membrane, ozone gas is introduced into the other side, and ozone gas is dissolved in pure water through the membrane, etc. Conceivable.
[0032]
In the contact method between pure water and ozone gas, it is considered economically that the ozone gas used is often exhausted ozone gas once used, so pure water is used on one side and ozone gas on the other side. A method of introducing ozone gas into pure water through a film is desirable. Contamination mixed in the exhaust ozone gas through the membrane does not contaminate the supplied pure water.
[0033]
Recently, in the same way as the ultrapure water containing residual hydrogen peroxide as described above, ultrapure water that has been deoxygenated by sparging nitrogen into pure water, or ultrapure water that has been evacuated to remove gas in the ultrapure water. (Deaerated ultrapure water).
[0034]
Even with such pure water, if the above-described mechanism is provided, pure water in which oxygen gas and ozone gas are mixed before being supplied will not cause a decrease in ozone gas generation due to the supplied pure water. Further, since the amount of pure water supplied and used for 1 g of ozone gas generated by such electrolysis is a very small amount of about 50 cc, a small amount of ozone gas is required for the mechanism.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Next, an example of an embodiment according to the present invention will be described with reference to the accompanying drawings.
[0036]
FIG. 1 is a conceptual diagram of a general electrolytic gas generator, and FIG. 2 is a conceptual diagram in which a mechanism for contacting ozone gas is incorporated in the supplied pure water in the electrolytic gas generator according to the embodiment of the present invention. is there.
[0037]
In FIG. 1, the ozone gas and hydrogen gas generator 1 of the electrolytic gas generator is provided with an ion exchange membrane 1a. Porous anode material 1b and cathode material 1c are provided on both sides of the ion exchange membrane 1a, respectively. By closely arranging and electrolyzing the ion exchange membrane 1a as a solid electrolyte, ozone gas and oxygen gas are produced from the anode side, and hydrogen gas is produced from the cathode side.
[0038]
Pure water 3 is supplied to the ozone gas and hydrogen gas generator 1. A power source 2 is connected to the generator 1, and gas is generated by current from the power source 2.
[0039]
The generated ozone and hydrogen gas are separated by the gas separation units 4 and 5, respectively, and led to the ozone gas conduit 9 and the hydrogen gas conduit 10.
[0040]
In FIG. 2, pure water 3 is supplied as ozone water 6 through an ozone gas contact mechanism 8 to the ozone gas and hydrogen gas generator 1 of the electrolytic gas generator. Further, a power source 2 is connected to the ozone gas and hydrogen gas generator 1, and gas is generated by the current from the power source 2.
[0041]
The ozone gas contact mechanism 8 is supplied with pure water 3 on one side and ozone gas 7 on the other side through a membrane. The generated ozone and hydrogen gas are separated by the gas separators 4 and 5 and guided to the ozone gas conduit 9 and the hydrogen gas conduit 10 as in FIG.
[0042]
【Example】
Next, although the Example of the electrolytic-gas generator concerning this invention is described, this Example does not limit this invention.
Example 1
Porous anode material and cathode material are arranged on both sides, respectively, and ultra-pure water containing 1 ppm of residual hydrogen peroxide is used as pure water, and pure water supplied to the anode chamber is used as its pure water. It was led to the anode chamber through a mechanism in which 0.3 g / hr ozone gas contacted through the PTFE membrane in the conduit. When electrolysis was performed by supplying 50 A from the power source, the amount of ozone gas generated from the anode was 2.8 g / hr. Electrolysis was carried out under the same conditions for 1 month, but there was no change in the amount of ozone gas.
(Comparative Example 1)
Electrolysis was carried out under the same conditions as in Example 1 except that the pure water supplied to the anode chamber was not passed through a mechanism in which ozone gas contacted.
[0043]
The amount of ozone gas generated from the anode was 1 g / hr, and the amount of generated ozone gas was reduced to 1/3 compared to Example 1. As in Example 1, electrolysis was performed for 1 month under the same conditions, but the amount of ozone gas did not increase and there was no change.
(Example 2)
Porous anode material and cathode material are respectively arranged on both sides thereof, and pure water containing 500 ppm of an organic substance is used as pure water, and the PTFE membrane is provided in the conduit for pure water supplied to the anode chamber. And then led to the anode chamber through a mechanism in which 0.3 g / hr of ozone gas contacts. When electrolysis was performed by supplying 50 A from the power source, the amount of ozone gas generated from the anode was 2.8 g / hr. Electrolysis was carried out under the same conditions for 1 month, but there was no change in the amount of ozone gas.
(Comparative Example 2)
The electrolysis was performed under the same conditions as in Example 2 except that the pure water supplied to the anode chamber was not passed through a mechanism in which ozone gas contacted.
[0044]
The amount of ozone gas generated from the anode was 1.5 g / hr, and the amount of ozone gas generated was halved compared to Example 2. As in Example 2, electrolysis was carried out under the same conditions for 1 month, but the amount of ozone gas did not increase and there was no change.
Example 3
Porous anode material and cathode material are respectively arranged on both sides, degassed pure water from which dissolved gas is removed up to 50 ppb is used as pure water, and pure water supplied to the anode chamber is used in the conduit. After passing through a mechanism in which 0.3 g / hr of ozone gas was contacted via a PTFE membrane, it was led to the anode chamber. When electrolysis was performed by supplying 50 A from the power source, the amount of ozone gas generated from the anode was 2.8 g / hr. Electrolysis was carried out under the same conditions for one month, but there was no change in the amount of ozone gas.
(Comparative Example 3)
Electrolysis was performed under the same conditions as in Example 3 except that the pure water supplied to the anode chamber was not passed through a mechanism in which ozone gas contacted.
[0045]
The amount of ozone gas generated from the anode was 2.2 g / hr, and the amount of generated ozone gas decreased compared to Example 3. As in Example 3, electrolysis was carried out under the same conditions for 1 month, but the amount of ozone gas did not increase and there was no change.
[0046]
【The invention's effect】
As described above, in the present invention, ozone gas and oxygen gas can be produced from the anode side, and hydrogen gas can be produced from the cathode side. At this time, ozone gas having a stable ozone concentration can be supplied.
[0047]
Moreover, a high concentration ozone gas concentration can always be generated.
[0048]
Furthermore, by using exhaust ozone gas once used, it has become possible to obtain a low-cost and compact electrolytic gas generator.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a general electrolytic gas generator.
FIG. 2 is a conceptual diagram of pure water supplied to the anode side in the electrolytic gas generator according to the embodiment of the present invention via an ozone gas contact mechanism.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ozone gas and hydrogen gas generation part 2 Power supply 3 Pure water 4 Ozone gas separation part 5 Hydrogen gas separation part 6 Ozone water 7 Ozone gas 8 Ozone gas contact mechanism 9 Ozone gas conduit 10 Hydrogen gas conduit

Claims (6)

Porous anode material and cathode material are arranged in close contact with both sides of the ion exchange membrane, and the ion exchange membrane is electrolyzed as a solid electrolyte, so that ozone gas and oxygen gas are supplied from the anode side and hydrogen gas is supplied from the cathode side. In an electrolytic gas generation method for producing gas,
An electrolytic gas generation method comprising contacting ozone gas with pure water supplied to the anode side and supplying the pure water as ozone water. The electrolytic gas generation method according to claim 1, wherein the ozone gas is ozone gas that has been used once. In the structure in which the pure water becomes ozone water, pure water is introduced into one side by a film formed of a fluororesin, ozone gas is introduced into the other side, ozone gas is dissolved in the pure water through the film, and the pure water is converted into ozone water. The electrolytic gas generation method according to claim 1 or 2, wherein the method has a structure. Porous anode material and cathode material are arranged in close contact with both sides of the ion exchange membrane, and the ion exchange membrane is electrolyzed as a solid electrolyte, so that ozone gas and oxygen gas are supplied from the anode side and hydrogen gas is supplied from the cathode side. In an electrolytic gas generator for producing gas,
An electrolytic gas generator having a structure in which ozone gas is brought into contact with pure water supplied to the anode side so that the pure water becomes ozone water. The electrolytic gas generator according to claim 4, wherein the ozone gas is ozone gas once used. In the structure in which the pure water becomes ozone water, pure water is introduced into one side by a film formed of a fluororesin, ozone gas is introduced into the other side, ozone gas is dissolved in the pure water through the film, and the pure water is converted into ozone water. 6. The electrolytic gas generator according to claim 4, wherein the electrolytic gas generator has a structure.

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