JPH09249403A - Generation of high concentration ozone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably generate high concentration ozone by diffusing heat generated by an electric discharge from both electrodes by constituting both of hollow cylindrical electrodes and a plate-like electrode to be exposed in the air and suppressing a temperature rising in a discharged space. SOLUTION: A dielectric substance 4 is stuck on a plate-like electrode 6. Plural hollow cylindrical electrodes (e.g. 1a and 1b) vertically fitted to an insulated board 2 so as the hollow cylindrical electrodes to be vertical to the dielectric substance 4 are provided on a packing 5 put on the periphery of the dielectric substance 4. Ozone is generated by applying high voltage between the hollow cylindrical electrodes 1a and 1b and the plate-like electrode 6 while flowing a gas from a gas inlet 9a of the hollow cylindrical electrode 1a into a hole 10a and flowing out the gas from a gas outlet 9b through a hole 10b of the hollow cylindrical electrode 1b in a state providing a distance between a surface of the dielectric substance 4 and electric discharging ends 11a and 11b of the hollow cylindrical electrodes 1a and 1b to be <=10mm.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Ozone has a strong oxidizing power and has a great effect on sterilization, decolorization, deodorization, etc., and is used in a wide range of fields such as industry, agriculture, fisheries, and medical care. In recent years, in particular, it has played an important role in global environmental protection such as purification of water and air, and also has applications in high-tech industries, biotechnology, pharmaceuticals, chemicals, power fuels, explosives, and the like.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION

2. Description of the Related Art There are many methods for producing ozone, but the most industrially used methods at present are those using silent discharge and creeping discharge. Silent discharge is a "columnar discharge" that occurs when a high voltage is applied while flowing a gas containing oxygen between electrodes with a dielectric such as glass, ceramic, or mica interposed between the electrodes. Since the ozone generation reaction is caused by the dissociation reaction caused by the collision between electrons and oxygen molecules, the fine glow-like discharge can generate ozone more efficiently than the columnar discharge. A glow-like discharge can be formed by a creeping discharge, but the structure is structurally disadvantageous to heat dissipation, and the heat generated by the discharge can only be removed indirectly.
There is a drawback that the temperature of the discharge space tends to rise. As described above, there is no current ozone generator that utilizes glow discharge and can efficiently remove heat generated by the discharge from the high voltage side and the low voltage side.

[0003]

In order to efficiently generate ozone, it is necessary to form an electrode that forms a glow discharge and allows the gas to pass through the glow discharge reliably. Also,
Suppressing temperature rise is an important issue for ozone generation. Therefore, it is necessary to show an electrode structure for effectively dissipating the heat generated by the discharge from both the high-voltage side and low-voltage side electrodes.

[0004]

[Means for Solving the Problems] A glow-like discharge can be generated by a hollow columnar electrode provided with a hole so that gas can be passed through along the central axis of the columnar electrode. Since the discharge end of the hollow cylindrical electrode is cut perpendicularly to the central axis, the cut surface and the side surface of the hollow cylindrical electrode are at right angles. Since the electric field is the highest at this right-angled corner, glow-like corona discharge occurs at this part. Since the hollow columnar electrode is used by attaching it to an insulating plate, the discharge end side has a stepped structure so as not to fall off from the insulating plate, or the hollow columnar electrode is insulated by providing a screw part on the heat radiating end side. Since it is fixed to the body or a radiator is attached, the parts other than the discharge end do not necessarily have to be cylindrical, but the discharge end must be cylindrical. A hollow columnar electrode is arranged perpendicularly to the dielectric provided in close contact with the plate electrode, and the distance between the discharge end of the hollow columnar electrode and the surface of the dielectric is 1 mm or less. The cut surface of the cylindrical electrode and the surface of the dielectric are placed parallel to each other. With such a configuration, gas is supplied from any hollow columnar electrode of the hollow columnar electrodes, and the gas is allowed to flow out from another hollow columnar electrode while the gas is discharged from the other hollow columnar electrode to the flat plate electrode. High frequency high voltage or high frequency pulsed high voltage is applied to. The structure of the flat plate electrode is such that the side opposite to the hollow columnar electrode is a flat plate, and the opposite side is not necessarily a flat plate for use as a heat dissipation and grounding electrode, and generally has a heat dissipation fin on one side. Using. Dielectric materials include glass, ceramics, mica,
Resin is used, but ceramic is desirable because it is robust and can be miniaturized. As the gas, oxygen or a dry gas containing oxygen is used. Since the ozone generation characteristics change depending on the waveform of the applied voltage, it is necessary to change the applied voltage waveform appropriately when the dielectric is glass or ceramic. In addition, in the construction of the ozone generator, the insulating plate having a plurality of hollow cylindrical electrodes attached is placed on a packing arranged around the dielectric provided on the flat plate electrode, Tighten and fix the periphery of the flat plate electrode with bolts and nuts at regular intervals. With such a structure, a closed discharge space is formed, and a gap of 1 mm or less is formed between the discharge end of the hollow cylindrical electrode and the dielectric. The gas supplied from the columnar electrode can flow out only from the other hollow cylindrical electrode. Also, the distance between the discharge end of the hollow cylindrical electrode and the dielectric can be adjusted by changing the packing thickness. The hollow cylindrical electrode used in this ozone generator is an ozone resistant metal such as stainless steel or titanium,
It is necessary to use a material with high electrical insulation such as Teflon, vinyl chloride, bakelite, etc. for the insulating plate, and silicone rubber or soft plastic for the packing as a material that is gas-shieldable and elastic enough to maintain a constant gap between the electrodes. There is. Aluminum or stainless steel is preferable for the plate electrode.

[0005]

In the above structure, when a high voltage is applied between the hollow cylindrical electrode and the flat plate electrode, the electric field is generated at the tip of the hollow cylindrical electrode on the side opposite to the dielectric, that is, the corner at the right angle of the discharge end. As a result, the circular corona discharge peculiar to the annular shape occurs on the circumference of the discharge end of the hollow cylindrical electrode. The corona discharge has a similar appearance to a glow discharge at low pressure and is a fine discharge, so it is described as a glow discharge. The discharge formed in the space between the hollow cylindrical electrode and the dielectric is a silent discharge. In the above electrode configuration, when a gas flows in from any hollow columnar electrode, the gas can be surely flown out from the other hollow columnar electrodes, so that the gas causes the glow discharge and the silent discharge generation region to occur. It will definitely pass. As a result, the gas dissociation action of discharge plasma such as glow discharge and silent discharge can be reliably used for ozone generation. Most of ozone is generated in the glow discharge part. Further, since the electrode end of the hollow columnar electrode that is not the discharge end, that is, the heat radiation end is exposed to the atmosphere, the heat generated at the discharge end and the discharge space is transferred through the hollow columnar electrode and radiated. Dissipated at the edge. The heat dissipation end is used as a gas supply port and a gas extraction port, and also functions as a radiator and can dissipate the heat generated by the discharge directly into the atmosphere, which contributes to good heat dissipation and stable ozone generation. ． On the other hand, the flat plate-shaped electrode has a role as a place to install a dielectric, a role as a ground electrode, and a role as a radiator. In this way, because of the structure in which heat can be dissipated from both the hollow cylindrical electrode and the flat plate electrode, a high cooling effect is obtained, and stable ozone generation characteristics and high concentration ozone generation are possible.

[0006]

1 is a conceptual diagram for explaining the basic principle of the present invention (partial sectional view). That is, a pair of hollow columnar electrodes 1a and 1b are attached to an insulating plate 2 with tightening nuts and heat radiating ends 3a and 3b, and the insulating plate 2 is placed on a packing 5 provided around a dielectric 4 to insulate the insulation. Bolts 7a and 7b and a nut 8 are provided around the plate 2 and the plate electrode 6 at regular intervals.
Tighten with a and 8b. As a result, the airtightness is maintained, and the gas introduced from the gas inlet 9a of the hollow cylindrical electrode 1a exits from the gas outlet 9b through the hole 10a, the hole 10b. The distance between the dielectric 4 and the discharge ends 11a and 11b can be adjusted by the thickness of the packing 5 (the portion constituted by a pair of hollow cylindrical electrodes as a basic unit in this manner is hereinafter referred to as "cell"). Fig. 2 is a conceptual diagram when two cells are connected in series in order to generate high-concentration ozone (partial cross-sectional view). That is, the gas flowing in from the gas inlet 29a of the hollow cylindrical electrode 21a passes through the holes 210a and 210b and passes through the gas outlet 2a.
9b, then into the next cell, hollow cylindrical electrode 2
Entered from the gas inlet 29c of 1c, holes 210c, 210d
Exit through the gas outlet 29d. In this way, by connecting multiple cells in series, it is possible to increase the ozone concentration one after another. FIG. 3 shows a case where eight hollow columnar electrodes are integrally formed, and the gas flowing in from the gas inlet 39a is four hollow columnar electrodes 31a, 31b, 3
The gas simultaneously flows out from the holes (310a to 310d) of 1c and 31d, and the gas thereof is hollow cylindrical electrodes 31e, 31f, and 31.
FIG. 3 is a conceptual diagram of an integral hollow columnar electrode in which the gas flows into the holes (310e to 310h) of g and 31h at the same time and exits from the gas outlet 39b (partial sectional view). In this figure, the gas inlet / outlet is provided on the side surface, but it can be provided on the heat dissipation end side of the surface. Also, the number of hollow cylindrical electrodes can be increased by any number. FIG. 4 is a conceptual diagram when an ozone generator is constructed using the integral hollow cylindrical electrode of FIG. By integrating multiple hollow cylindrical electrodes in this way, the connection for gas supply and voltage application becomes easy and the structure is simplified. The gas supply method is the same as in the case of FIG. 3, and the gas flowing in from the gas inlet 49a passes through the four hollow cylindrical electrodes 41a, 41b, 41c, 41d and the other four
The hollow cylindrical electrodes 41e, 41f, 41g, and 41h enter into the hollow cylindrical electrodes 41 and exit from the gas outlet 49b. Since any number of hollow columnar electrodes can be provided, it is possible to increase the concentration of ozone and increase the amount of ozone generation by increasing the number of hollow columnar electrodes. However, the discharge end part of the integrated hollow cylindrical electrode must be separated from each other, but the other parts can be made into an integrated structure.

In the ozone generator characterized in that the glow discharge is particularly well formed in the ozone generator in which the distance between the surface of the dielectric and the discharge end of the hollow cylindrical electrode is set within 1 mm, ozone The generation efficiency increases.
In addition, the diameter of the cylindrical portion at the discharge end of the hollow cylindrical electrode is set to 10
The ozone generation efficiency is high when the size is between ~ 30 mm. The thickness of the dielectric is 0.6 to 0.8 mm, ceramics or glass, mica, etc. are used, and the frequency of the applied voltage can be as high as 10 kHz to 20 kHz.

In the ozone generator according to the first aspect of the present invention, the side surface of the discharge end of the hollow cylindrical electrode and the cut surface of the hollow cylindrical electrode facing the dielectric are formed so as to be at right angles to each other. , A glow discharge can be effectively generated by the edges formed at right angles.

In the ozone generator according to claim 1, in order to make the diameter of the heat radiation end of the hollow columnar electrode as close as possible to the diameter of the discharge end, the difference in diameter between the discharge end and the heat radiation end is set to 10 mm. The effect of heat dissipation becomes large if the distance is within a millimeter. In addition, the ozone generation characteristics are stabilized when the heat dissipation edge is made uneven to improve heat dissipation.

A plurality of ozone generators according to claim 1 are connected in series, in parallel, or in combination with series and parallel to increase the concentration of ozone or generate a large amount of ozone. Can be done.

In the ozone generator according to the first aspect of the present invention, the hollow cylindrical electrode has a structure in which one end of the hollow cylindrical electrode is exposed to the atmosphere as a heat dissipation end, so that heat is efficiently dissipated and the ozone generation characteristic is improved.

In the ozone generator based on the basic principle of claim 1, as shown in FIG. 3, the discharge end portions of the plurality of hollow columnar electrodes are configured to be separated from each other, but the other portions are integrally structured. A method of generating ozone by using a body-shaped hollow columnar electrode and flowing gas out of an arbitrary hollow columnar electrode group into another hollow columnar electrode group facilitates gas supply and voltage application. The structure of the ozone generator is simplified, the characteristics and reliability are improved, and maintenance and inspection are easy.

[0013]

EFFECT OF THE INVENTION Since the present invention has a structure in which both the hollow cylindrical electrode and the flat plate electrode are exposed to the atmosphere, in order to dissipate the heat generated by the discharge from both electrodes,
Highly concentrated ozone can be generated stably by suppressing the temperature rise in the discharge space. Moreover, by connecting the cells in series or in parallel, it was possible to increase the ozone concentration almost proportionally one after another. The ozone generation characteristics obtained by these comprehensive effects reached an ozone concentration of about 200 g / m ³ (about 100,000 ppm) and an energy efficiency of 200 g / kWh in the oxygen source. This is about twice the characteristics obtained with the current industrial ozone generators. According to the present invention, the most important problem in ozone generation is solved, which enables improvement of ozone generation efficiency and generation of high-concentration ozone. The device according to the invention, not only can be utilized in an ozone generator, purifier of applying the discharge plasma water and air, the chemical reactor of various gases, chemical synthesis furnace, NO x, _{SO x,} freon,
It can be used by incorporating it in a part of various devices such as a device for decomposing and removing pollutants such as organic solvents.

[0014]

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing the principle of the present invention (partial sectional view).

FIG. 2 is a conceptual diagram of an embodiment to which the principle of the present invention is applied (partial sectional view).

FIG. 3 is a conceptual diagram of an integrated hollow cylindrical electrode.

FIG. 4 is an ozone generator using an integrated hollow cylindrical electrode (partially sectional view).

[0015]

[Explanation of symbols]

1a, 1b, 21a, 21b, 21c and 21d are hollow cylindrical electrodes. 11a, 11b, 211a, 211b, 211c, 21
1d is a discharge end 2, 22 and 42 are insulating plates. 3a, 3b, 23a, 23b, 23c and 23d are tightening nuts and heat radiating ends, respectively. 31a, 31b, 31c, 31d, 31e, 31f, 3
1g, 31h, 41a, 41b, 41c, 41d, 41
e, 41f, 41g and 41h are integral hollow cylindrical electrodes 4, 24 and 44 are dielectrics, respectively. 5, 25 and 45 are packing respectively. 6, 26 and 46 are flat plate electrodes. 7a, 7b, 27a, 27b are bolts 8a, 8b, 28a, 28b are nuts 9a, 9b, 29a, 29b, 29c, 29d, 39
a, 39b, 49a, 49b are gas inlets / outlets 10a, 10b, 210a, 210b, 210c, 21 respectively.
0d, 310a, 310b, 310c, 310d, 31
0e, 310f, 310g and 310h are holes

Claims (1)

[Claims] 1. A hollow cylindrical electrode having a hole for passing a gas therethrough along a central axis, a dielectric, a plate-like electrode, and an insulator or packing for forming these, A structure in which a plurality of hollow columnar electrodes are attached vertically to the insulating plate so that the hollow columnar electrodes are perpendicular to the dielectric, and the dielectric is closely attached to the plate electrode. Installed on the packing placed around the dielectric,
In addition, with the distance between the dielectric surface and the discharge end of the hollow columnar electrode being set to 10 mm or less, gas is introduced from any hollow columnar electrode of the hollow columnar electrode, and the gas is replaced with other gas. A method of generating ozone, in which a high voltage is applied between the hollow columnar electrode and the flat plate-like electrode while flowing out from the hollow columnar electrode to generate ozone.