JPH1111910A - Ozone generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dissolve a defect that is low in ozone production efficiency of a conventional silent discharge type or an impulse type ozone generator. SOLUTION: Relating to the impulse type ozone generator by which an impulse current is allowed to flow from a peaking condenser becoming an output stage of a pulse power source 13 to a loop between an earth side electrode 11 and a high voltage side electrode 12 to generate ozone, the peaking condenser is arranged proximately between a current terminal 14 of the high voltage side electrode and the earth side electrode, and floating impedance from the peaking impedance to the current loop between the electrodes is minimized and the production efficiency of ozone is enhanced and also discharge of noise is minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone generator which applies an impulse voltage between electrodes to generate ozone from a raw material gas supplied to a gap between the electrodes, and more particularly to an impulse generation power supply and an electrode structure.

[0002]

2. Description of the Related Art Ozone has an extremely strong oxidizing power and is used for water and sewage treatment and human waste treatment such as sterilization, deodorization and decolorization. Industrially, a large amount of ozone is required at a high concentration, and thus, currently, it is mainly produced by a silent discharge method.

[0003] In this method, a raw material gas (air or oxygen) is used.
And ozone is electrochemically generated from the material. As shown in principle in FIG. 8, dielectrics 3 and 4 are provided on the high-voltage electrode 1 and the ground electrode 2 respectively, and the dielectrics opposing each other with a gap are provided. An AC or high-frequency high voltage is applied from a power supply 5 to the electrode (a single-sided metal electrode is also possible). By this voltage application, an aggregate of minute discharge columns (silent discharge) is generated between the dielectrics 3 and 4, and each of them is generated in a very short pulse to generate non-equilibrium plasma and generate ozone. .

[0004]

Although the silent discharge type ozone generator is the most effective method used industrially, the ozone generation efficiency is still low and the cost of ozone is increased. The electric power (discharge power consumption) necessary to obtain unit ozone is theoretically 1.2 kWh / kg · O ₃
On the other hand, at present, about 14 kWh / kg · O _{3 is} required, only a few% of the electric power is used for ozone generation, and most of the electric power is lost to exhaust heat.

[0005] The efficiency of ozone generation greatly depends on the discharge energy, discharge shape, temperature, and pressure in the reaction space. Therefore, (1) the shape of the electrode and the dielectric, (2) the applied voltage and frequency, and (3) the reaction space. Conventionally, a device for optimizing the cooling has been performed. However, no remarkable improvement in discharge power consumption has been observed.

An object of the present invention is to provide an ozone generator having an improved ozone generation efficiency.

[0007]

The present invention SUMMARY OF] during the pulse power supply becomes output stage peaking capacitor C _P more current terminal and a ground electrode of the electrode portion of the sensor for current monitoring in the impulse ozone generator Or the spacer that supports the high-voltage side electrode in the ground side electrode, minimizes the wiring of the pulse current loop flowing between the peaking capacitor and the electrode, and reduces the floating impedance of the wiring in principle. To the limit,
The ozone generation efficiency is increased and the emission of noise is reduced as much as possible.

(First Invention) An impulse voltage is applied from a pulse power supply between a ground electrode and a high-voltage electrode which are opposed to each other with a gap in which a raw material gas flows, and a discharge generated in the gap is electrochemically generated. In an impulse-type ozone generation device that generates ozone from a raw material gas by utilizing a peaking capacitor that forms an output stage of the pulse power supply and forms a pulse current loop with the electrode,
It is characterized in that it is disposed between the current terminal of the high voltage side electrode and the ground side electrode.

(Second Invention) The present invention is characterized in that a sensor for monitoring a pulse current of the current loop is provided at a connection between the peaking capacitor and a ground electrode.

(Third invention) An impulse voltage is applied from a pulse power source between a ground side electrode and a high voltage side electrode which are opposed to each other with a gap through which a raw material gas flows, and discharge generated in the gap is electrochemically generated. In an impulse-type ozone generation device that generates ozone from a raw material gas by utilizing a peaking capacitor that forms an output stage of the pulse power supply and forms a pulse current loop with the electrode,
It is characterized in that the ground-side electrode is also used as a spacer for supporting the high-voltage side electrode.

[0011]

FIG. 9 shows the basic structure of an impulse type ozonizer (ozone generator). In the electrode section, a needle-shaped high-voltage side electrode (metal) 12 is provided inside a cylindrical ground-side electrode (metal) 11, and a discharge space is formed between both electrodes. The pulse power supply 13 supplies a pulse having a sharp rise and a short duration between the electrodes 11 and 12.
The source gas is blown from one of the electrodes 11 and is extracted as ozone generated from the other.

The pulse power supply 13 is, for example, as shown in FIG.
The circuit configuration shown in FIG. Energy storage capacitor C ₀ is the initial charging by the DC power supply, a route of saturable reactors SI ₀ and the pulse transformer PT from the capacitor C ₀ generates a pulse current I ₀ by turning on the semiconductor switches GTO. Pulse current boosted by transformer PT charges the capacitor C ₁ is boosted by the saturable transformer ST, trans ST and the high voltage and pulses the magnetic pulse compression by the magnetic switch operation of the saturable reactor SI ₁ to peaking capacitor C _P Generates current. An impulse current is generated between the capacitor _CP and the electrodes 11 and 12 of the ozone generator.

Further, the specific structure of the impulse type ozonizer is configured as shown in FIG. The electrode section is cooled by passing cooling water through the ground electrode 11, and the high voltage electrode 12 is connected to the peaking capacitor (C _P ) 15 of the pulse power supply 13 via the current terminal 14. The current monitoring sensor 16 obtains a pulse current monitoring signal.

In such an impulse type ozonizer, when an impulse is applied between the electrodes 11 and 12, a uniform non-equilibrium plasma discharge is formed in a discharge space in the electrode 11. In order to obtain industrially required high-concentration ozone, it is necessary to increase the ozone concentration in the equilibrium state by increasing the production of ozone while reducing the decomposition.

For the production of ozone, it is necessary to dissociate oxygen molecules to generate oxygen atoms as a first reaction, and first, electrons having sufficient energy are required. Subsequently, the reaction of generating ozone from oxygen atoms and the reaction of decomposing the generated ozone again proceed simultaneously, but both are reactions having temperature dependency. The lower the temperature, the more the chemical equilibrium leans toward the generation side, so that high-concentration ozone can be generated. That is, the gas temperature must be low.

A non-equilibrium plasma satisfies such a condition. In non-equilibrium plasmas, only electrons with low mass gain high energy from the electric field (high electron temperature)
However, molecules and ions are in a state of low energy (low gas temperature) because they cannot follow a rapid change in the electric field. Therefore, ozone can be efficiently generated by using non-equilibrium plasma.

The conventional silent discharge method also uses non-equilibrium plasma, but since the silent discharge is a collection of minute streamer discharges, the electron density is not uniform. For this reason, in the spot where energy is injected, the electron density necessary for oxygen atom generation is concentrated, but at the same time, the gas temperature is high in a spot-like manner, so that the chemical equilibrium is hardly inclined to ozone generation. Therefore, the ozone generation efficiency as a whole does not improve.

Since the discharge using the pulse power source occurs uniformly in the reaction space and there is no spot having a high gas temperature, the characteristics of the non-equilibrium plasma can be effectively used. Therefore, discharge power consumption can be suppressed low.

The pulse power type ozonizer is applied with an impulse voltage that rises very quickly and has a short width. In order to supply the ozone generator, which is a load, without any loss to the electric power containing a large amount of high-frequency components in this manner, FIG.
The wiring of the ordinary circuit as shown in FIG.

In order to transmit the impulse effectively, it is necessary to take a structural measure to minimize the floating impedance of the line. In order to improve the transmission of the impulse, it is desirable to minimize the loop of the wiring between the peaking capacitor Cp and the load (the ozone generator electrode).

However, in the structure shown in FIG. 11, since the wiring loop is large, the stray impedance hinders transmission of high frequency components. Further, in such a case, since power cannot be supplied efficiently, there are many problems that the current loses its place and emits very strong noise.

As described above, in this embodiment, a part of the output circuit of the pulse power supply is incorporated in the structure of the ozone generator. Hereinafter, embodiments will be described in detail.

(First Embodiment) A structure in which Cp is installed in parallel with a current terminal.

FIG. 1 shows the main structure of the present embodiment. FIG. 11 differs from FIG. 11 in that a peaking capacitor (C
p) 15 is provided between the current terminal 14 of the ozone generation electrode section and the ground electrode 11 to minimize the wiring of a current loop (indicated by an arrow) flowing from the peaking capacitor 15 to the electrodes 11 and 12. .

The current terminal 14 is a terminal for applying an impulse voltage to the high-voltage electrode 12 in the hermetic container. An insulator such as an insulator is used as a center electrode so that the high voltage does not short-circuit to the grounded hermetic container. The structure is covered.
This method is the shortest wiring when the peaking capacitor 15 is grounded outside the airtight container.

(Second Embodiment) A structure in which a current monitoring sensor is installed at a connection between Cp and a ground electrode.

As shown in FIG. 2, in order to monitor the current supplied to the ozone generating electrode portion, in addition to the structure shown in FIG.
A current monitoring sensor 16 is provided at the connection between the peaking capacitor 15 and the ground electrode 11.

In the present embodiment, the structural effect on the noise resistance of the ozone generator is the same as that of the structure shown in FIG.

It is necessary to constantly monitor the current supplied to the ozone generator in order to confirm the operation state of the ozone generator. However, in the impulse-type ozonizer, the current is a very difficult problem because the current probably contains a high frequency component.

In the conventional type, the current monitoring sensor is installed at the position shown in FIG. 10, but it is difficult to measure accurately due to the floating impedance generated in the wiring.

In this embodiment, the peaking capacitor 1
By installing the current monitoring sensor 16 between the airtight container 5 and the confidential container forming the ground electrode 11, the floating impedance of the wiring is extremely reduced, and the current which minimizes the influence of disturbance such as noise due to the discharge of the ozone generator is minimized. Monitoring becomes possible.

As described above, according to the first and second embodiments, it was confirmed by experiments that the floating impedance of the wiring in the impulse type ozonizer can be reduced to the minimum in principle.

FIG. 3 shows a current waveform I _out (actually measured value) with respect to the impulse voltage V _CP in the ozone generator in the conventional structure, and FIG. 4 shows a current waveform in the structure of the same embodiment. In FIG. 3, resonance due to floating LC of the wiring appears strongly. While this parasitic vibration is a source of noise and affects the equipment, the parasitic vibration which is a problem in FIG. 4 is greatly reduced.

(Third Embodiment) A structure in which _CP is installed in an electrode container.

As shown axial sectional view in FIG. 5 and the electrode portion constituted by the A-A 'sectional view, placing the peaking capacitor C _P in the ozone generating electrode unit. The mounting bracket 17 for the high-voltage electrode 12 is conventionally made of an insulator, but is replaced with a conductor such as a metal, and a spacer 18 for supporting the same.
Is partially replaced by a peaking capacitor (C _P ) 15 to double as a spacer. The spacer 18 is an insulator.

Since the peaking capacitor 15 is directly exposed to the ozone gas, it is protected by an ozone-resistant coating.

With such a structure, the loop of the pulse current flowing between the peaking capacitor 15 and the electrodes 11 and 12 becomes extremely small, and the floating impedance can be minimized. Further, generation of noise can be reduced.

As shown in FIG. 6, the same operation and effect can be obtained by applying the present invention to a structure in which a plurality of discharge portions are arranged in parallel as shown in FIG. Further, in the electrode portion structure of FIG. 6, as shown in FIG. 7, a structure in which a capacitor is provided with a peaking capacitor 15 in a spacer portion, and a structure in which discharge energy and a floating impedance of a discharge portion are equalized. it can.

[0039]

As described above, according to the present invention, the peaking capacitor C _P and the current monitoring sensor are arranged close to the current terminal of the electrode section and the ground electrode, or the peaking capacitor C _{P is connected} to the ground electrode. Because it also serves as a spacer for supporting the high-voltage side electrode, (1) the floating impedance generated in the wiring can be reduced, (2) the generation of noise originating from the ozone generator can be reduced, and (3) disturbance There is an effect that a current that is not affected can be detected.

[Brief description of the drawings]

FIG. 1 is a structure showing an embodiment of the present invention.

FIG. 2 is a structure showing another embodiment of the present invention.

FIG. 3 shows applied voltage and current waveforms of an ozone generation device having a conventional structure.

FIG. 4 shows applied voltage and current waveforms of the ozone generation device according to the embodiment.

FIG. 5 is a structure showing another embodiment of the present invention.

FIG. 6 is a structure showing another embodiment of the present invention.

FIG. 7 is a structure showing another embodiment of the present invention.

FIG. 8 shows a silent discharge type ozone generator.

FIG. 9 shows a basic structure of an impulse type ozonizer.

FIG. 10 shows an example of a pulse power supply.

FIG. 11 shows a conventional structure of an impulse type ozone generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Grounding electrode 12 ... High voltage electrode 13 ... Pulse power supply 14 ... Current terminal 15 ... Peaking capacitor 16 ... Current monitoring sensor 17 ... High voltage electrode mounting bracket 18 ... Spacer

Claims (3)

[Claims] 1. An impulse voltage is applied from a pulse power source between a ground side electrode and a high voltage side electrode which are opposed to each other with a gap through which a raw material gas flows, and a discharge generated in the gap is electrochemically used. In an impulse-type ozone generation apparatus for generating ozone from a raw material gas, a peaking capacitor which is an output stage of the pulse power supply and forms a pulse current loop with the electrode is grounded to a current terminal of the high-voltage side electrode. An ozone generator characterized by a structure arranged close to between side electrodes. 2. The ozone generation apparatus according to claim 1, wherein a sensor for monitoring a pulse current of the current loop is provided at a connection between the peaking capacitor and a ground electrode. 3. An impulse voltage is applied from a pulse power source between a ground side electrode and a high voltage side electrode which are opposed to each other with a gap through which a raw material gas flows, and a discharge generated in the gap is electrochemically utilized. In an impulse type ozone generation apparatus for generating ozone from a raw material gas, a peaking capacitor which is an output stage of the pulse power supply and forms a pulse current loop between the electrode and the electrode is provided in the ground side electrode in the high voltage side. An ozone generator characterized by a structure also serving as a spacer for supporting an electrode.