JPH0859209A - Electric source for ozonizer - Google Patents

Abstract

PURPOSE: To continuously generate discharge of alternating current without interruption and to increase an amount of ozone generated by superimposing a pulse voltage having fixed electric charge to an AC voltage during inversion of polarity of an AC voltage to be impressed between a high-voltage electrode and an earth electrode and impressing the superimposed voltage. CONSTITUTION: This ozonizer is a silent discharge and impresses an AC voltage or an AC current between a high-voltage electrode and an earth electrode opposingly arranged through a discharging gap and generates ozone in a raw material gas circulated in the discharging gap. The ozonizer is equipped with an electric source for superimposing a pulse voltage or a pulse current having a fixed electric charge on the AC voltage or the AC current and impressing the superimposed voltage during inversion of polarity of the AC voltage or the AC current to be impressed between the high-voltage electrode and the earth electrode of the ozonizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silent discharge type ozone generator used for water treatment, human waste treatment and the like, and more particularly to a power supply applied between electrodes.

[0002]

2. Description of the Related Art Ozone has an extremely strong oxidizing power and is used for many purposes such as water and sewage treatment such as water sterilization, deodorization and decolorization, human waste treatment and food related sterilization. The ozone generation method includes an ultraviolet irradiation method, a radiation irradiation method, a plasma discharge method, a silent discharge method, and a water electrolysis method.
The silent discharge method is mainly used industrially.

FIG. 4 shows the principle of an ozone generator using the silent discharge method. In FIG. 4, the high voltage electrode 1 and the ground electrode 2
Are arranged side by side with a dielectric 4 interposed therebetween so that a void 3 is formed therebetween. AC between both electrodes 1 and 2
A voltage is applied to generate a silent discharge in the void 3, and a raw material gas (dry air or oxygen) is passed through the void 3 to generate ozone.

The theoretical yield of ozone O ₃ is O ₂ → O + O-118 Kcal (endothermic reaction) O + O ₂ → O ₃ +25 Kcal (exothermic reaction), resulting in 3O ₂ → 2O ₃ -68 Kcal, and 1 mol of O ₃ is produced. 34 Kcal is required. Therefore, the theoretical yield is 1.2 kgO ₃ / KW
h. However, the ozone generation efficiency with respect to the power consumption is extremely low compared to the theoretical yield and is only a few percent, and the remaining 9
The current state of the ozone generator is that 0% or less of electric power does not contribute to ozone generation as heat.

[0005]

The main factors affecting the amount of ozone produced are the shape of the electrodes, the size of the gap between the electrodes, the shape and material of the dielectric, the cooling method of the electrodes,
Examples of the method include dehumidifying and cooling the source gas, and the waveform of the applied voltage.

As shown in FIG. 4, the current ozone generator mainly has a structure which applies a silent discharge in which a dielectric is interposed so that a gap is formed between electrodes and a discharge is generated in the gap. Has become. In FIG. 4, when silent discharge occurs, a large number of minute streamer-like discharge columns are generated in the void 3 between the electrode and the dielectric, and a large amount of electrons flow in the discharge columns. At that time, oxygen molecules O ₂ in the raw material gas flowing in the voids collide with electrons, and due to impact ionization, oxygen atoms O ₂ are generated.
And excited oxygen molecules O ₂ * are generated and react with the oxygen molecules O ₂ to generate ozone O ₃ (discharge chemical action).

Here, the principle of ozone generation will be described in detail with reference to FIG. In FIG. 5, when an AC voltage is applied to generate silent discharge, a minute half-wave of an AC voltage in which the dielectric-side electrode 1 is positive and the ground-side electrode 2 is negative is generated, In the streamer-like discharge column, electrons move from the side of the ground electrode 2 to the side of the dielectric 4 having a high potential, and the electrons spread over a surface of the dielectric 4 in a certain area and are deposited.
Then, the streamer-like discharge column generated next avoids a large number of electrons already deposited, reaches another portion of the surface of the dielectric 4 where no electrons are yet deposited, and similarly a large number of electrons are deposited on the surface. Deposit. By repeating this, the places where electrons are deposited are dispersedly present on the surface of the dielectric 4.

The polarity of the voltage is reversed and the electrode 1 on the side of the dielectric 4
Is negative and the electrode 2 on the ground side becomes positive and silent discharge occurs, the electrons accumulated on the surface of the dielectric move in the streamer-like discharge column to the side of the ground electrode 2 where the electric potential becomes higher this time. To do. In this way, when the electrons move between the electrode and the dielectric, they collide with oxygen molecules O ₂ in the raw material gas as described above to generate ozone O ₃ .

As described above, the ozone generation is closely related to the discharge current. However, the electrodes of the ozone generator have conventionally been supplied with a square wave constant current as shown in FIG. 6, for example. Figure 6
As described above, when a normal alternating current is applied to the electrodes, there is a time region in which no discharge current flows when the polarity is reversed. While the discharge is continuous, ultraviolet light and ions are present in the discharge space, and the next discharge is likely to occur after one minute discharge.However, once the discharge is stopped, the next discharge is compared with the continuous discharge. It becomes difficult to get up. Discontinuing the discharge in this way is not preferable for ozone generation.

As described above, the conventional apparatus for generating ozone by simply applying AC current or AC voltage between the electrodes has a drawback that discharge is interrupted and ozone generation efficiency is poor.

The present invention has been made in view of the above points, and an object thereof is to provide a power supply for an ozone generator in which alternating current discharge is continuously generated without interruption to increase ozone generation amount with respect to input power amount. To provide.

[0012]

According to the present invention, (1) an alternating voltage or an alternating current is applied between a high voltage electrode and a ground electrode, which are arranged to face each other through a discharge gap, and are circulated in the discharge gap. In a silent discharge type ozone generator for generating ozone in a raw material gas, when the polarity of an alternating voltage or an alternating current applied between the high-voltage electrode and the ground electrode is reversed, a pulse voltage or a pulse current having a predetermined charge amount is generated. And (2) the pulse voltage or the pulse current is synchronized with the AC voltage or the AC current, and (2) the pulse voltage or the pulse current is synchronized with the AC voltage or the AC current. 3) The amount of electric charge that the pulse voltage or the pulse current has is an amount required to change the potential difference of the discharge gap by the amount of the discharge start voltage and the discharge extinction voltage. It is characterized in that.

[0013]

Since the pulse voltage or the pulse current is superimposed on the voltage or current supplied between the electrodes, the polarity between the discharge gaps is instantly reversed, and the AC discharge is continuously generated without interruption. Therefore, the amount of ozone produced at the same power density is higher than that of the conventional device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the present invention, the power supply device is configured so that, when the polarity of the current supplied between the high voltage electrode and the ground electrode is reversed, a pulse current of, for example, 10 μs is superimposed and applied to the reversed polarity as shown in FIG. did. The total charge amount of the pulse current is adjusted to an amount necessary to change the potential difference between the discharge gaps just before and after applying the pulse by the amount of addition of the discharge start voltage and the discharge extinction voltage of the gap.

When the ozone generator is operated with the new current waveform shown in FIG. 1, the polarity between the gaps is instantly reversed, and the AC discharge is continuously generated without interruption as shown in the current waveform shown in FIG. The power supply waveforms to be combined with the pulse are shown in Table 1 below, and an experiment was carried out under the following conditions using each power supply waveform in Table 1.

[0016]

[Table 1]

Experimental conditions Glass tube outer diameter φ63.4 * 500 (electrode portion 400) Raw material gas pressure 0.6 kgf / cm ² G Water temperature 25 ° C. Flow rate 8.5 l / min Power supply frequency 1 KH _{Z For the} examples of Table 1 of the present invention FIG. 3 shows the relationship between the amount of generated ozone and the discharge power consumption per unit area under the conditions.
In FIG. 3, each example number corresponds to the experiment number in Table 1, and the conventional example number in the figure shows the result when the experiment was performed under the same conditions as above using a power supply waveform not combined with a pulse. ing. According to FIG. 3, it can be seen that the ozone generation amount at the same power density is increased in each of the examples as compared with the conventional example. The pulse current may be a pulse voltage.

[0018]

As described above, according to the present invention, in the silent discharge type ozone generator, a predetermined charge amount is generated when the polarity of the alternating voltage or alternating current applied between the high voltage electrode and the ground electrode is reversed. Since the pulse voltage or pulse current is applied so as to be superimposed on the AC voltage or AC current, the AC discharge can be continuously generated without interruption, and thus the conventional device can be used. In comparison, the amount of ozone generated increases with the same discharge power consumption.

[Brief description of drawings]

FIG. 1 is a waveform diagram showing a current waveform of a power supply according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing a current waveform when the ozone generator is operated by the power supply of the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the discharge power and the ozone generation amount in each example of the present invention.

FIG. 4 is an explanatory diagram showing an outline of ozone generation by a silent discharge method.

FIG. 5 is an explanatory diagram showing the principle of ozone generation by the silent discharge method.

FIG. 6 is a waveform diagram showing a current waveform when operating with a conventional ozone generator power supply.

[Explanation of reference numerals] 1 ... High-voltage electrode 2 ... Ground electrode 3 ... Void portion 4 ... Dielectric material

Claims (3)

[Claims] 1. A silent discharge type in which an AC voltage or an AC current is applied between a high-voltage electrode and a ground electrode, which are opposed to each other via a discharge gap, to generate ozone in a raw material gas circulated in the discharge gap. In the ozone generator of
When the polarity of the alternating voltage or alternating current applied between the high-voltage electrode and the ground electrode is reversed, a pulse voltage or pulse current having a predetermined charge amount is superimposed and applied to the alternating voltage or alternating current. A power supply for an ozone generator, which is characterized in that 2. The power supply for an ozone generator according to claim 1, wherein the pulse voltage or the pulse current is synchronized with the AC voltage or the AC current. 3. The amount of electric charge contained in the pulse voltage or the pulse current is an amount necessary to change the potential difference of the discharge gap by an amount corresponding to the addition of the discharge start voltage and the discharge extinction voltage. The ozone generator power source according to claim 1 or 2.