JP2000195645A - Discharging electrode and ozonizer with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electrodes stably controlling a gas electric discharge and having a long life and to provide a device stably generating a large quantity of ozone and easily controlling the generation quantity by using a metal electrode having a porous surface made by anodization for at least one electrode. SOLUTION: The other electrode of gas discharging electrodes may be a metal electrode having the same anodization film, and it preferably has a surface made of a high-dielectric constant material is particular. Al2O3, TiBaO3, TiSrO3 can be used for the high-dielectric constant material, for example. The anodization surface of the metal electrode having the anodization surface is preferably applied with a hydration process and a baking process to obtain a finer diameter. The hydration process can be easily applied when the metal electrode is immersed in water of 5 deg.C or above for 5 min or longer, preferably in water of 50-80 deg.C for about 5-10 min in particular. The metal electrode is preferably air-baked at 300-500 deg.C after the hydration process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a discharge electrode,
Particularly excellent discharge stability and long life electrode for discharge,
And an ozone generator using the electrode.

[0002]

2. Description of the Related Art Since ozone is highly toxic, high speed ppc
As for ozone generated in a charging process in a copying machine or the like, a recovery device is provided. On the other hand, the activity of ozone is also actively used in deodorizing devices and sterilizing devices. Further, it is possible to oxidize other harmful substances by using the activity of ozone and detoxify it, but in this case, a large amount of ozone is often required.

However, for example, it is difficult to contain more than 1% of ozone by air discharge.
Conventionally, when such a high concentration of ozone is required, it is necessary to use oxygen gas instead of air, which is complicated. Further, there is a disadvantage that the life of the discharge electrode is shortened. Furthermore, when such a large amount of ozone is actively used, not only must the emission concentration be strictly controlled in order to ensure safety, but also ozone is used as a reaction raw material. Needs to be stabilized. However, if an attempt is made to increase the amount of ozone generated, corona discharge tends to be non-uniform, and the amount of ozone generated tends to be unstable.

[0004]

The inventors of the present invention have conducted intensive studies on a method of stabilizing gas discharge, and as a result, have determined that at least one metal electrode having a porous surface by anodic oxidation is used as a gas electrode. It has been found that the discharge can be extremely stabilized and that the life of the discharge electrode can be prolonged, and that a large amount of ozone can be stably supplied by using this electrode in an ozone generator to discharge air. They have found that they can do so and arrived at the present invention.

Accordingly, a first object of the present invention is to provide a discharge electrode which is suitable for stably controlling gas discharge and has a long life. A second object of the present invention is to provide an ozone generator capable of stably generating a large amount of ozone and easily controlling the amount of ozone generated.

[0006]

The above objects of the present invention are to provide a pair of electrodes for gas discharge, wherein at least one of the electrodes is a metal electrode having a surface made porous by anodic acid. An electrode for discharge, an ozone generator using the electrode, and a method for producing ozone, wherein a large amount of ozone is stably generated by adjusting the interval and the voltage between the electrodes to a certain range. Achieved by

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A gas discharge in the present invention is a normal gas discharge in which an AC voltage is normally applied between two electrodes in the presence of a gas to generate a discharge. Is also possible. The gas used in this case is not particularly limited, and can be appropriately selected according to the purpose. For example, when it is desired to generate ozone, air or oxygen may be used.

The gas discharge electrode of the present invention is a metal electrode having at least one of a pair of electrodes having a surface made porous by anodic oxidation (hereinafter referred to as an anodic oxide film). The other electrode is not particularly limited, and may be a metal electrode having the same anodic oxide film, but is particularly preferably an electrode having a surface made of a substance having a high dielectric constant. As such a substance having a high dielectric constant, for example,
Al ₂ O ₃ , TiBaO ₃ , TiSrO _{3 and the} like can be mentioned.

The material of the metal electrode having the anodic oxide film is as follows:
For example, a metal such as aluminum alone, a metal having an aluminum layer provided on the surface by a cladding method or a thermal spraying method, and a duralumin containing 60% by weight or more of aluminum can be used. Anodization of these metals can be easily performed by a known method.

[0010] The structure of the electrode in the present invention is not particularly limited, and may be not only a parallel line and a plane, a plane and a plane, but also a linear or rod-shaped electrode disposed at the center of the cylindrical inner surface and the center thereof. good. Further, fin-shaped projections may be formed on the inner surface of the cylinder. Since ozone can be easily generated by applying an AC voltage while flowing air or oxygen to the housing containing the electrode of the present invention, the ozone can be used as an ozone generator.

Since the discharge in this device is extremely stable, the amount of generated ozone is stable, and the quantitative control can be easily and reliably performed. Further, by flowing an exhaust gas containing an odorous substance or a volatile organic compound together with the air or oxygen, the odorous substance or the volatile organic compound can be efficiently oxidized and removed. Further, exhaust gas containing dioxin and the like generated by incineration of garbage can be treated to remove dioxin and the like.

It is preferable that the distance between the discharge electrodes is designed so that it can be appropriately adjusted depending on the gas to be used, the gas pressure, the applied voltage and the like. In particular, from the viewpoint of stably generating a large amount of ozone by discharging under atmospheric pressure, it is preferable to set the interval between the discharge electrodes to about 0.5 to 2 mm.
The voltage applied between the electrodes at this time is preferably 4 to 10 kv.

Further, it is preferable that the anodic oxidation surface of the metal electrode having the anodic oxidation surface is further subjected to hydration treatment and calcination treatment to make pores more fine. The hydration treatment can be easily performed by immersing in water at 5 ° C. or more for 5 minutes or more, and particularly preferably immersed in water at 50 to 80 ° C. for about 5 to 10 minutes. After the hydration treatment,
It is preferable to perform air calcination at ~ 500 ° C.

[0014]

As the discharge electrode of the present invention uses at least one electrode having a surface which is uniformly porous by anodic oxidation, it is possible to discharge extremely stably without generating sparks and to perform anodic oxidation. Long life due to having a film. Therefore, by using this electrode for an ozone generator, a large amount of ozone can be stably supplied, which is suitable for the oxidative decomposition reaction of harmful substances.

[0015]

EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

Examples 1 and 2 and Comparative Example 1. As the electrode material, a heat sink aluminum having a thickness of 0.5 mm and a size of 5 cm × 5 cm was used. In 4% by weight oxalic acid, 2
Anodize by passing a current of 50 A / m ² at 5 ° C. for 1 hour,
When this was used for the electrodes on both sides (Example 1), after anodic oxidation in exactly the same manner, hydration treatment was performed at 80 ° C. for 1 hour,
The air discharge was performed for the case where the material fired at 400 ° C. for 1 hour was used as the electrodes on both sides (Example 2) and the case where untreated heat sink aluminum was used for the electrodes on both sides (Comparative Example 1). The ozone concentration is as shown in FIG. In addition, for the discharge, the distance between the electrodes was fixed at 0.5 mm, and the voltage between the electrodes was changed in a range of 3 to 7 kv.
An air discharge was performed at atmospheric pressure.

As is apparent from FIG. 1, the amount of ozone generated in Example 1 in which only the anodic oxidation treatment was performed was larger than that in Comparative Example 1 in which no voltage was applied when a voltage of 4 kV or more was applied. In the case of Example 2 in which anodizing treatment and hydration treatment were performed to provide smaller pores on the surface, the applied voltage was not less than about 3.2 kv, and the ozone concentration was higher than that in the case of the untreated comparative example 1. It has been proved that the amount of generation of the gas increases, that is, the discharge efficiency is good. In addition, in the case of Comparative Example 1, the discharge was also unstable, but in Examples 1 and 2, it was confirmed that the discharge was extremely stable.

Further, if the discharge is continued at about 6 kv, the discharge state becomes remarkably unstable in about 1 hour in the case of no treatment, whereas in the case of Example 1, after 15 hours,
It was only a little unstable, and in the case of Example 2, it was confirmed that the discharge was completely stable even after continuous discharge for 24 hours.

Embodiment 3 FIG. When the same voltage was applied to each electrode to discharge air using a medium-sized reactor in which four electrodes used in Example 2 were closely arranged in series, the results shown in FIG. 2 were obtained. .

Comparative Example 2 The result shown in FIG. 2 was obtained in exactly the same manner as in Example 3, except that the electrode used in Comparative Example 1 was used instead of the electrode used in Example 2.

The results of the above Examples and Comparative Examples show that the use of an electrode having an anodic oxide film enables a stable discharge of gas. As a result, the concentration of chemical species caused by discharge of ozone or the like can be reduced. This demonstrates that it can be increased more than before.

[Brief description of the drawings]

FIG. 1 is a graph showing the applied voltage dependence of the concentration of ozone generated by discharge, corresponding to Examples 1 and 2 and Comparative Example 1.

FIG. 2 is a graph showing the applied voltage dependence of the concentration of ozone generated by discharge, corresponding to Example 3 and Comparative Example 2.

[Explanation of symbols]

ヒ ー ト シ ン ク Untreated heatsink aluminum electrode □ Heatsink aluminum electrode treated only by anodic oxidation treatment ヒ ー ト シ ン ク Heatsink aluminum electrode treated by hydration treatment after anodizing treatment Reference No. P98-798

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D002 AA21 AB02 AB03 AC04 BA05 BA07 CA20 DA51 GA01 GA02 GB02 GB20 4G042 CA01 CC06 CC20

Claims (4)

[Claims] 1. A discharge electrode comprising a pair of electrodes for gas discharge, wherein at least one electrode is a metal electrode having a surface made porous by anodic oxidation. 2. The discharge electrode according to claim 1, wherein a pair of an electrode having a high dielectric constant and a metal electrode having a surface made porous by anodic oxidation are paired. 3. The surface made porous by anodic oxidation,
The discharge electrode according to claim 1, wherein the electrode is a surface that has been made more porous by a hydration treatment and a baking treatment. 4. An ozone generator comprising at least a pair of electrodes installed in a housing having at least an air or oxygen gas supply port and an exhaust port, wherein the electrodes are any one of the above-described electrodes. An ozone generator characterized in that it is such an electrode.