JP2002249877A - Electrode device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode device which stably generates plasma near the atmospheric pressure and decomposes organic gas. SOLUTION: As one embodiment of rotational floating multipole discharge device, an electrode 110 is constituted so as to bury screws 116 of 3ϕ concentrically at an interval of 4.5 mm into an insulator disk 114. The electrode 110 of such a constitution is disposed in an atmosphere of organic gas such as methane and ethylene near the atmospheric pressure, the electrode 110 is rotated at 2-10 rpm by a central shaft 112 and a voltage is applied to the two screws of the outer periphery via brushes 118. Then, discharge is generated between the screws of a path A-B which connects the two brushes 118 and the plasma is formed. The path through which the discharge is generated is changed at all times because the circular insulator is rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an electrode device,
In particular, the present invention relates to a floating electrode device capable of stably generating plasma near the atmospheric pressure and decomposing an organic gas or the like.

[0002]

BACKGROUND ART Conventionally, low pressure (10-2 to 10-3) has been used.
Torr), methane gas and the like are decomposed by microwave-excited plasma, and diamond film or DLC (Diamond-like c
The technique of forming an arbon) film is well known as microwave excited plasma CVD. However, when trying to decompose organic gas such as methane and ethylene close to the atmospheric pressure into hydrogen and carbon, there are problems such as difficulty in forming a stable plasma by microwave excitation and the necessity of large power.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrode device capable of generating plasma stably near atmospheric pressure and decomposing organic gas and the like.

[0004]

In order to achieve the above object, the present invention provides an insulating disk, a plurality of electrodes formed on the disk, a driving unit for rotating the disk and the electrodes, An electrode device, comprising: a pair of brushes provided on an outer periphery of an electrode; and a power supply for generating a voltage to be applied to the brush, wherein the electrode forms plasma by discharge in a gas near atmospheric pressure. It is. The power supply generates a pulse, and the pulse has a waveform having a low voltage plateau following a high voltage spike, and by using this pulse, an organic gas near atmospheric pressure can be decomposed. .

[0005]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a rotating floating multi-pole discharge device for generating plasma. In FIG.
As one embodiment of the rotating floating multipolar discharge device, a 3φ screw (screw length: 30 mm) 116 is embedded concentrically at 4.5 mm intervals in an insulator disk 114, and the electrode 1
10. The electrode 110 having such a configuration is
The electrode 110 is placed in an atmosphere of an organic gas such as methane or ethylene near the atmospheric pressure, and the electrode 110 is moved by a central axis 112 for 2 to 10 r.
pm, the brush 11
A voltage is applied via 8. Then, two brushes 11
Discharge occurs between the screws in the path AB connecting the lines 8 and plasma is formed. The path of the discharge is constantly changed due to the rotation of the circular insulator. The formed plasma is stable, and the stable plasma is obtained by embedding each screw 116 in the insulating disk 114 and electrically floating each other.

FIG. 2 is a photograph showing a state in which plasma is formed. The discharge condition for taking this photograph is discharge of air at atmospheric pressure, and the applied voltage is 6.6 KV. The applied voltage is, as shown in FIG.
A high voltage is applied to the electrode (screw) from a power supply of 0 volts by the Slidac 124 and the induction coil 126. The photograph in FIG. 2 shows a state in which the electrode in FIG. 1 is turned upside down and discharged. As can be seen from the photograph of FIG.
Plasma is formed around all the screws on the circular insulator. This is because the path in which the discharge occurs is always changed because the insulator has been transferred. Since plasma is formed around many screws as described above, it is possible to efficiently perform decomposition of an organic gas or the like. In order to decompose the organic gas and separate it into hydrogen and carbon components, a pulse as shown in FIG. In FIG. 3, when a sharp pulse of about 1000 volts is applied at about 1000 volts, gas decomposition can be caused. Subsequently, a voltage of about 200 volts and about 0.5 msec is applied. By using a pulse having a waveform having a low voltage plateau following such a high voltage spike, the carbon component can be deposited in a film shape.

[0007]

EXAMPLE The rotating electrode of FIG. 1 was installed upside down, covered with an airtight cylinder having a diameter of 150φ having an inlet and an outlet, and filled with gas. Then, while applying a pulse voltage as shown in FIG. 3 for a predetermined time while rotating the rotating electrode, the gas inside was analyzed. (Example 1) 1 atmosphere of air: methane in an airtight cylinder
The mixed gas flows at a ratio of 0: 1. This is to mix air for the purpose of examining the decomposition efficiency and the effect of the presence of air. The decomposition is performed without air. The decomposition state is measured as follows. (1) Insert a small tube for gas collection into an airtight cylinder and collect gas in a small vacuum flask. (2) The collected gas is subjected to mass spectrometry using gas chromatography. FIG. 4 shows the measurement results of the collected gas using gas chromatography. In FIG. 4, the horizontal axis: mass and the vertical axis: intensity of each mass. FIG. 4A shows an analysis result before discharge. This figure clearly shows the presence of methane (m / z = 16) and air components (m / z ≒ 16: nitrogen, 32: oxygen). FIG. 4B shows a case where the discharge time is 10 minutes while rotating the rotating electrode. From this figure, methane is almost completely decomposed. Further, the air component is also reduced due to a chemical reaction. In addition, although the component of m / z = 41-42 is not exactly known, carbon dioxide may have been polymerized. The generated hydrogen is not detected because it is very small.

Example 2 One atmosphere and one liter of methane gas were sealed in an airtight cylinder. Then, a pulse voltage as shown in FIG. 3 was applied for 30 minutes while rotating the rotating electrode, and then the gas inside was analyzed. As a result, hydrogen: 992 ml and methane: 8 ml. Black objects were deposited on the inner wall of the cylinder. This black body is a carbon component, but we have not confirmed what its allotropic nature is.

(Example 3) Under the same conditions as described above, the sealed gas was changed to 2.7% by volume of carbon monoxide based on nitrogen, and a decomposition treatment was performed by electric discharge. As a result, carbon monoxide after the decomposition treatment was reduced to 0.6% by volume.

[0010]

As described above, by using the electrode device of the present invention, a stable plasma can be formed in an organic gas atmosphere near the atmospheric pressure, and the gas can be decomposed compared to the microwave-excited plasma. Easy. Further, compared to generating microwaves, the power for generating plasma to the electrode device of the present invention is smaller.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a rotating floating multi-pole discharge device.

FIG. 2 is a photograph showing that plasma is generated in a rotating floating multipolar discharge device.

FIG. 3 is a diagram showing a waveform of a pulse applied to decompose an organic gas in a rotating floating multipolar discharge device.

FIG. 4 is a diagram showing a result of decomposing a mixed gas of methane and air.

[Explanation of symbols]

 110 electrode 112 central axis 114 insulator disk 118 brush 122 ac power supply 124 slidac 126 induction coil 128 resistance

Continued on the front page F-term (reference) 4G075 AA03 AA62 BA01 BA05 CA15 CA20 DA02 DA12 EA02 EB41 EC21 EC30 ED01 ED08 ED20 EE13 FC11 4K030 AA09 BA27 FA03 JA09 JA17 KA15

Claims (2)

[Claims] An insulating disk; a plurality of electrodes formed on the disk; a driving unit for rotating the disk and the electrodes; a pair of brushes installed on the outer periphery of the electrode; An electrode device comprising: a power source for generating a voltage to be applied; and forming plasma by discharge in the gas near atmospheric pressure by the electrode. 2. The electrode device according to claim 1, wherein the power supply generates a pulse, the pulse having a waveform having a low voltage plateau following a high voltage spike, and an organic near atmospheric pressure. An electrode device for decomposing gas.