JP2004167315A - Gas exciting apparatus and gas exciting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas exciting apparatus which excites gas efficiently to bring about dissociation or ionization to generate a low temperature plasma with high efficiency, and an air exciting method using the apparatus. <P>SOLUTION: The gas exciting apparatus 10 is constituted so that at least a pair of electrodes 4A and 4B, which are connected to an AC power supply, are provided in a housing 1 having an inflow opening part 2 for a gas to be treated and a discharge opening part 3 for the treated gas. (1) one electrode among both electrodes comprises a core electrode and the insulating sheath body for surrounding the core electrode and the outside surface of the insulating sheath body is a protective electrode coming into contact with the gas to be treated, (2) the other electrode among them is an exposed electrode coming into direct contact with the gas to be treated and (3) the exposed electrode and the housing are together earthed. The gas to be treated is excited by passing the gas to be treated through the housing 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas excitation device and an excitation method. ADVANTAGE OF THE INVENTION According to this invention, a gas can be efficiently excited, dissociated or ionized, and low-temperature plasma can be generated with high efficiency.
[0002]
[Prior art]
Various devices are known as a gas excitation device that induces a gas under AC high-pressure discharge conditions to excite gas molecules and generate low-temperature plasma. For example, Japanese Patent Application Laid-Open No. 9-199261 (Patent Document 1) And US Pat. No. 5,483,117 (Patent Document 2) also describe a gas excitation device. FIG. 1 shows a typical embodiment of such a conventionally known gas excitation device. FIG. 1 is a schematic perspective view showing a part of a side wall of a housing 51 of a gas excitation device 50, which is cut away. The gas excitation device 50 has a substantially rectangular parallelepiped housing 51 provided with an opening 52 for inflow of the gas to be processed G and an opening 53 for discharge of the processed gas C. Inside the housing 51, A large number of protection electrodes 54 are provided. As shown in the schematic sectional view of FIG. 2, the protection electrode 54 includes a core electrode 55 and a cylindrical sheath 56 surrounding the core electrode 55, and the cylindrical sheath 56 is It is made of an insulating material. Further, the protective electrode 54 is divided into two groups of electrode groups 54A and 54B, which are connected to electric wires 57A and 57B, respectively, and the electric wires 57A and 57B are connected to an AC power supply 58. An electric wire 57B connected to one of the electrode groups 54B is grounded. As shown in FIG. 2, each of the protection electrodes 54 </ b> B disposed on the outermost side inside the housing 51 and facing the inner wall of the housing 51 is grounded so as not to generate a discharge between the inner electrodes of the housing 51. It is preferable to connect to the electric wire 57B. In principle, it is not necessary to ground the housing 51 itself, but it is preferable to ground the housing 51 itself from the viewpoint of safety.
[0003]
Further, a deodorizer and an air purifier using a low-temperature non-equilibrium plasma generated by the gas excitation device are known. For example, Japanese Patent Application Laid-Open No. 2001-293079 (Patent Document 3) discloses a low-temperature plasma deodorizing apparatus having a high-pressure discharge unit for generating low-temperature plasma and a catalyst unit disposed downstream thereof and filled with an oxidation promoting catalyst. Is described. The high-pressure discharge unit generates radicals by giving dissociation energy to the gas to be treated by high-pressure discharge. That is, the electrons emitted into the gas by the discharge impinge on the gas molecules in the odor gas and activate the molecules. Some of the active molecules are dissociated into radicals, which are considered to oxidize and decompose malodorous substances in the odor gas or generate ozone. It is considered that the ozone generated by the radical also oxidizes the malodorous substance and contributes to the treatment of the malodorous substance. Further, the odorous substance is oxidatively decomposed by the energy of the discharge itself.
[0004]
[Patent Document 1]
JP-A-9-199261 [Patent Document 2]
US Patent No. 5,483,117 [Patent Document 3]
JP 2001-293079 A
[Problems to be solved by the invention]
In the gas excitation device of the type shown in FIGS. 1 and 2, the excitation capability of the entire device is determined depending on the number of protection electrodes provided in the cylindrical housing 51. However, there is a limit to the number of protection electrodes that can be arranged in a certain volume. Therefore, means for improving the excitation ability of the entire apparatus without increasing the number of protective electrodes has been required.
Further, in the gas excitation device of the type shown in FIGS. 1 and 2, it is necessary to replace a consumable protective electrode, and the protective electrode has a complicated structure, so that it is expensive and requires replacement of the electrode. When the running cost becomes expensive and the insulator sheath is made of a material that is easily damaged, such as a glass tube, it is necessary to pay attention to the handling of the protective electrode.
Accordingly, an object of the present invention is to provide a gas excitation device of the type shown in FIGS. 1 and 2 that increases the amount of plasma generated in the cylindrical housing 51, simplifies the electrode structure, and reduces costs. It is in.
[0006]
[Means for Solving the Problems]
According to the present invention, there is provided a gas excitation apparatus including at least one pair of electrodes connected to an AC power supply in a housing having an opening for inflow of a gas to be processed and an opening for discharge of a processed gas. So,
(1) One of the electrodes is a protection electrode comprising a core electrode and an insulator sheath surrounding the core electrode, and an outer surface of the insulator sheath contacts a gas to be treated;
(2) An exposed electrode in which the other electrode is exposed and is in direct contact with the gas to be treated, and (3) the exposed electrode and the housing are both grounded. This can be solved by an excitation device.
[0007]
According to a preferred aspect of the device of the present invention, the protection electrode is an electrode filled with a liquid (for example, oil or water) in a gap between a core electrode and an insulator sheath surrounding the core electrode; The liquid causes the fine gap to disappear.
According to another preferred aspect of the device of the present invention, the core electrode of the protective electrode is cylindrical or cylindrical, the sheath of the protective electrode is cylindrical, and the exposed electrode is a cylindrical or cylindrical electrode. In addition, the sheath and the exposed electrode are arranged in parallel at a distance from each other, and in a direction perpendicular to the flow direction of the gas to be treated.
According to still another preferred aspect of the device of the present invention, the apparatus includes a protective electrode group including a plurality of protective electrodes and an exposed electrode group including a plurality of exposed electrodes.
[0008]
Further, the present invention has an opening for inflow of a gas to be treated and an opening for discharge of a treated gas, and allows passage of the gas to be treated into a housing provided with at least one pair of electrodes connected to an AC power supply. Let
A method of exciting an object gas by applying an AC potential to at least one pair of electrodes,
(1) One of the electrodes is a protection electrode comprising a core electrode and an insulator sheath surrounding the core electrode, and an outer surface of the insulator sheath contacts a gas to be treated;
(2) An exposed electrode in which the other electrode is exposed and is in direct contact with the gas to be treated, and (3) the exposed electrode and the housing are both grounded. It also relates to the excitation method.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The device of the present invention is a gas excitation device obtained by improving the conventional gas excitation device of the type shown in FIGS. First, the difference between the basic structure of the apparatus of the present invention and the conventional apparatus will be described with reference to FIGS.
FIG. 3 is a schematic sectional view showing the basic structure of the conventional device shown in FIGS. 1 and 2. The conventional device 50 has a housing 51 provided with an opening 52 for inflow of a gas G to be treated and an opening 53 for discharge of a treated gas C. Inside the housing 51, protective electrodes 54A, 54B are provided. , 54B. Each of the protective electrodes 54A, 54B, 54B includes a core electrode 55 and a sheath 56 surrounding the core electrode 55. The electrode 54A is connected to an electric wire 57A, the electrodes 54B and 54B are connected to an electric wire 57B, and the electric wires 57A and 57B are connected to an AC power supply 58. Further, since the electrodes 54B, 54B are arranged outside the housing 51 and face the inner wall of the housing 51, the electric wires 57B connected to them are grounded.
[0010]
FIG. 4 is a schematic sectional view showing the basic structure of the device of the present invention. The device 10 of the present invention has a housing 1 having an opening 2 for inflow of a gas G to be treated and an opening 3 for discharge of a treated gas C. Inside the housing 1, a protective electrode 4A, Exposed electrodes 4B, 4B are provided. As described above, the conventional device 50 includes the protection electrodes 54A, 54B and 54B, whereas the device 10 of the present invention includes the exposed electrodes 4B and 4B instead of the protection electrodes 54B and 54B. Different. The protection electrode 4 </ b> A includes a core electrode 5 and a sheath 6 surrounding the core electrode 5, similarly to the conventional device 50. The protection electrode 4A is connected to the electric wire 7A, the exposed electrodes 4B and 4B are connected to the electric wire 7B, and the electric wires 7A and 7B are connected to the AC power supply 8. The electric wire 7B connected to the exposed electrodes 4B, 4B is grounded. Further, in the device 10 of the present invention, the housing 1 also needs to be grounded, which also differs from the conventional device 50. In the device 10 of the present invention, it is preferable to apply a high voltage to the protective electrode 4A side, and therefore, it is not preferable to dispose the protective electrode 4A at the outermost portion inside the housing 1. That is, as shown in FIG. 4, it is preferable that the exposed electrodes 4 </ b> B, 4 </ b> B are arranged on the outermost side inside the housing 1 and face the inner wall of the housing 1.
[0011]
In the conventional device shown in FIG. 3, discharge occurs between the core electrode 55 in the protection electrode 54A and the core electrodes 55 in each of the protection electrodes 54B on both sides. In this discharge, two insulator layers of the two sheaths 56 are interposed between the pair of core electrodes 55. On the other hand, in the device 10 of the present invention shown in FIG. 4, a discharge occurs between the core electrode 5 in the protection electrode 4A and each of the exposed electrodes 4B on both sides. In this discharge, only one of the insulator layers of the one sheath 6 is interposed between one core electrode 5 and the exposed electrode 4B, and the excitation ability is improved. It increases remarkably (see Examples described later). In the device 10 of the present invention shown in FIG. 4, since the housing 1 and the exposed electrodes 4B, 4B are grounded, no discharge occurs between the housing 1 and the exposed electrodes 4B, 4B.
[0012]
As shown in FIG. 4, in the gas excitation device 10 of the present invention, a combination of the protection electrode 4A and the exposed electrode 4B is used instead of the pair of protection electrodes 54A and 54B in the conventional device shown in FIGS. There are only differences. Therefore, a specific embodiment of the gas excitation device according to the present invention will be described with reference to FIGS. That is, FIG. 5 is a schematic perspective view showing a part of the side wall of the housing 1 of the gas excitation device 10 cut away, and FIG. 6 is a schematic sectional view thereof.
[0013]
As shown in FIGS. 5 and 6, in the gas excitation device 10 according to a specific embodiment of the present invention, like the conventional device 50, the inflow of the gas to be treated G into the portion corresponding to the upper surface of the substantially rectangular parallelepiped housing 1 is performed. The housing 1 is provided with an opening 3 for discharging the treated gas C at a portion corresponding to the bottom surface of the housing 1. A plurality of cylindrical protective electrodes 4A and a plurality of cylindrical exposed electrodes 4B are parallel and spaced apart from each other inside the housing 1 where high-pressure discharge processing (excitation processing) is performed. The electrodes are arranged perpendicular to the flow direction of the processing gas, and both ends of each of the electrodes are supported by support walls 1A and 1B of the housing 1, respectively.
[0014]
The protection electrode 4A includes a core electrode 5 and a cylindrical sheath 6 surrounding the core electrode 5 as in the conventional device 50, and the cylindrical sheath 6 is made of an insulating material. Consists of The core electrode 55 and the inner surface of the cylindrical sheath body 56 may be in a completely non-contact state, a complete contact state, or a partially and partially non-contact state. When the core electrode 55 and the inner surface of the cylindrical sheath body 56 are in a non-contact state in at least one portion, the gap is filled with air or a suitable protective gas, or filled with a liquid, It is preferable to prevent contact with the contaminated air to be treated.
[0015]
On the other hand, the cylindrical exposed electrode 4B has substantially the same dimensions as the cylindrical sheath 6 of the protective electrode 4A, and is in direct contact with the gas to be treated since the electrode surface is exposed. The plurality of protective electrodes 4A and the plurality of exposed electrodes 4B are grouped and connected collectively to electric wires 7A and 7B, and the electric wires 7A and 7B are connected to an AC power supply 8. Further, an exposed electrode 4B is arranged at the outermost part in the housing 1, and an electric wire 7B connected to the plurality of exposed electrodes 4B is grounded. Further, the housing 1 is also grounded.
[0016]
When the gas G to be treated flows through the inflow opening 2 of the gas processing apparatus 10 according to the present invention and a high voltage is applied to the two electrode groups 4A and 4B by the AC power supply 8, the two electrode groups 4A and 4B are formed. Discharge occurs between the two, and gas molecules are excited with higher efficiency than conventional devices to generate radicals. These radicals oxidize and decompose malodorous substances in the gas to be treated or generate ozone, so that the gas to be treated is oxidized. In addition, the gas to be treated is discharged from the discharge opening 3 together with the radicals and ozone generated in this way, and sent to a catalyst section (not shown) filled with an oxidation promoting catalyst, and the radical and ozone are treated with the gas to be treated. The reaction can proceed further, and the gas treatment can be continued.
[0017]
The exposed electrode used in the apparatus of the present invention can be made of any conductive material, and examples thereof include aluminum or an alloy thereof, copper, a carbonaceous material, iron or an alloy thereof, and tungsten. Since the exposed electrode is in direct contact with the gas to be treated, it is preferable to use a metal having corrosion resistance and easy to maintain such as a cleaning operation and a replacement operation, for example, stainless steel (for example, SUS). preferable.
Also, the shape of the exposed electrode is not particularly limited, but is manufactured by twisting a rod-shaped body (for example, a cylindrical body or a columnar body, particularly a cylindrical body or a columnar body), or a conductive wire. A stranded wire type electrode can also be used.
[0018]
In the device of the present invention, the arrangement of the plurality of exposed electrode groups and the plurality of protective electrode groups is such that discharge occurs almost uniformly inside the housing, and the gas to be treated passing between the electrodes is almost uniformly treated. There is no particular limitation as long as they are arranged. However, the plurality of exposed electrode groups and the plurality of protective electrode groups are arranged in parallel at a distance from each other and perpendicular to the flow direction of the gas to be treated, and one exposed electrode has four protective electrodes. It is preferable that the electrodes are surrounded by the electrodes, and one protective electrode is arranged so as to be surrounded by the four exposed electrodes.
[0019]
For example, as shown in FIG. 7, an electrode row 4A-10 including a plurality of protection electrode groups 4a-11 and 4a-12 arranged in series along the flow direction of the gas to be treated, and a flow of the gas to be treated similarly Similarly, between the electrode row 4A-20 and another electrode row 4A-20 including a plurality of protective electrode groups 4a-21 and 4a-22 arranged at the same interval as the electrode row 4A-10 in the direction. An electrode array 4B comprising a plurality of exposed electrode groups 4b-11, 4b-12, and 4b-13 arranged in series along the gas flow direction and at the same interval as the electrode arrays 4A-10 and 4A-20. Place -10. At this time, for example, it is preferable that the exposed electrodes 4b-12 be shifted so that they are at the same distance as the four adjacent protection electrodes 4a-11, 4a-12, 4a-21, and 4a-22. Similarly, the protection electrode 4a-22 included in the electrode row 4A-20 also has four adjacent exposed electrodes included in the electrode rows 4B-10 and 4B-20 arranged in parallel on both sides of the electrode row 4A-20. It is preferable to shift the electrodes 4b-12, 4b-13, 4b-22, and 4b-23 so as to have the same distance.
Although different from the embodiment shown in FIG. 7, the electrode row of the protection electrode group and the electrode row of the exposed electrode may be arranged in series in a direction perpendicular to the flow direction of the gas to be treated.
[0020]
In the gas excitation apparatus of the present invention, except for the above-mentioned exposed electrode, a conventionally known gas excitation apparatus (for example, an apparatus described in the above-mentioned Japanese Patent Application Laid-Open No. 9-199261 or US Pat. No. 5,483,117). ) Can be used as they are.
[0021]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, but these do not limit the scope of the present invention.
Embodiment 1
The test was performed using the same apparatus as the gas excitation apparatus 10 of the present invention shown in FIGS. As the exposed electrode, a cylindrical SUS electrode (outer diameter = 4 mm) was used, and 114 electrodes were installed as shown in FIGS. Further, as the protective electrode, a rod-shaped aluminum core electrode (outer diameter = 1.5 mm) and a cylindrical glass sheath (outer diameter = 4 mm) were used. For use, 74 electrodes were installed as shown in FIGS. As the housing, a rectangular solid made of polyphenylene sulfide (PPS) (length = 48 cm; width = 48 cm; depth = 11 cm) was used. In addition, a 15 KV power supply was used as an AC power supply, and was connected to a wire to which the exposed electrode group was connected together and a wire to which the protection electrode group was connected together. Further, the electric wire to which the exposed electrode group was collectively connected and the housing were both grounded. While passing air (normal temperature) as a gas to be treated through this apparatus at a speed of 0.24 m / sec, the applied AC voltage was increased from 0 to about 14 kV. The amount of ozone generated was measured by an ultraviolet absorption type measuring instrument provided at the discharge opening. The obtained result is shown by a curve a in FIG.
[0022]
[Comparative Example 1]
An experiment similar to that of the first embodiment was performed using the gas excitation device used in the first embodiment, in which a protection electrode group was provided instead of the exposed electrode group. The results are shown in curve b of FIG.
[0023]
【The invention's effect】
According to the apparatus of the present invention, since the excitation efficiency can be increased as compared with the conventional apparatus, the amount of plasma generated is also increased, and therefore, more gas is processed at the same applied voltage, or the same amount of gas is used. Can be processed with a low applied voltage. In addition, since the structure of one half of the electrode group is simplified, manufacturing costs and maintenance costs can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a conventional gas excitation device in which a side wall of a housing is partially cut away.
FIG. 2 is a schematic sectional view of the gas excitation device of FIG.
FIG. 3 is a schematic sectional view showing the basic structure of a conventional device.
FIG. 4 is a schematic sectional view showing a basic structure of the device of the present invention.
FIG. 5 is a schematic perspective view of the gas excitation device according to the present invention, in which a part of a side wall of a housing is cut away.
6 is a schematic sectional view of the gas excitation device of FIG.
FIG. 7 is a schematic sectional view showing a preferred arrangement of a plurality of protective electrode groups and a plurality of exposed electrode groups in the gas excitation device according to the present invention.
FIG. 8 is a graph showing experimental results performed in Example 1 and Comparative Example 1.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Housing; 1A, 1B ... Support wall; 2 ... Inflow opening part;
3 ... opening for discharge; 4A ... protective electrode;
4A-10, 4A-20... Protective electrode row;
4a-11, 4a-12 ... Protective electrode group;
4a-21, 4a-22 ... protective electrode group;
4B ... exposed electrode; 4B-10, 4B-20 ... exposed electrode row;
4b-11, 4b-12, 4b-13 ... exposed electrode group;
4b-21, 4b-22, 4b-23 ... exposed electrode group;
5: core electrode; 6: cylindrical sheath; 7A, 7B: electric wire;
8 ... AC power supply; 10 ... Gas excitation device;
50 ... gas excitation device; 51 ... housing; 52 ... inflow opening;
53: discharge opening; 54 (54A, 54B): protective electrode;
55: core electrode; 56: cylindrical sheath; 57A, 57B: electric wire;
58: AC power supply; G: gas to be processed; C: processed gas.

Claims (5)

A gas excitation device including at least one pair of electrodes connected to an AC power supply in a housing having an opening for inflow of a gas to be processed and an opening for discharge of a processed gas,
(1) One of the electrodes is a protection electrode comprising a core electrode and an insulator sheath surrounding the core electrode, and an outer surface of the insulator sheath contacts a gas to be treated;
(2) An exposed electrode in which the other electrode is exposed and is in direct contact with the gas to be treated, and (3) the exposed electrode and the housing are both grounded. Excitation device. The gas excitation device according to claim 1, wherein the protection electrode is an electrode in which a liquid is filled in a gap between a core electrode and an insulator sheath surrounding the core electrode. The core electrode of the protective electrode is cylindrical or cylindrical, the sheath of the protective electrode is cylindrical, the exposed electrode is a cylindrical or cylindrical electrode, and the sheath and the exposed electrode are interconnected. The gas excitation device according to claim 1, wherein the gas excitation device is arranged in parallel at a distance from each other and in a direction perpendicular to the flow direction of the gas to be treated. The gas excitation device according to any one of claims 1 to 3, including a protective electrode group including a plurality of protective electrodes and an exposed electrode group including a plurality of exposed electrodes. Having an opening for inflow of the gas to be treated and an opening for discharge of the treated gas, passing the gas to be treated into a housing having at least one pair of electrodes connected to an AC power supply,
A method of exciting an object gas by applying an AC potential to at least one pair of electrodes,
(1) One of the electrodes is a protection electrode comprising a core electrode and an insulator sheath surrounding the core electrode, and an outer surface of the insulator sheath contacts a gas to be treated;
(2) An exposed electrode in which the other electrode is exposed and is in direct contact with the gas to be treated, and (3) the exposed electrode and the housing are both grounded. Excitation method.

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