WO2018009027A1

WO2018009027A1 - Electromagnetic wave plasma torch

Info

Publication number: WO2018009027A1
Application number: PCT/KR2017/007308
Authority: WO
Inventors: 홍용철
Original assignee: 한국기초과학지원연구원; 주식회사 엔팩
Priority date: 2016-07-08
Filing date: 2017-07-07
Publication date: 2018-01-11
Also published as: KR101707177B1

Abstract

The electromagnetic wave plasma torch according to the present invention comprises: a plasma generation unit; a microwave generation unit for transmitting microwaves to the plasma generation unit; a plasma source gas injection unit for injecting a plasma source gas into the plasma generation unit; a microwave transmission line for the transmission of the microwaves to the plasma generation unit; a circular resonator which is provided in the plasma generation unit, is provided at an end of the microwave transmission line in TE₁₀ mode so as to induce a magnetic field, and converts to TM_0m0 mode in which the induced magnetic field induces an electric field to a central part, thereby generating plasma; and a circular waveguide in TM₀₁ mode so that the plasma generated by interactions in TE₁₀ mode, TM_0m0 mode, and/or coaxial mode absorbs all electromagnetic waves so as to allow for plasma generation without any loss, thereby enabling natural ignition, thus electrodelessly generating plasma, and having the effect of reducing inconvenience arising from maintenance, such as electrode replacement and electrode contaminant removal. (Representative Drawing) Fig. 5

Description

Electromagnetic plasma torch

The present invention relates to an electromagnetic plasma torch, and more particularly, to improve the efficiency of a conventional plasma torch, rectangular waveguide (TE ₁₀ mode), circular resonator (TM _0m0 mode), circular waveguide (TM ₀₁ mode), coaxial resonator The present invention relates to an electromagnetic plasma torch capable of various plasma treatments in a (TEM mode) mode, and in particular to enable plasma natural ignition in a coaxial resonator (TEM mode) mode.

Plasma torches using electromagnetic waves are widely used in various fields such as exhaust gas treatment, chemical vapor deposition, and surface modification.

Republic of Korea Patent No. 10-1166444 relates to a plasma source gas torch generated by electromagnetic waves and its application, the purpose is to generate a pure plasma torch by heating the plasma source gas with electromagnetic waves and to generate the gas, liquid Or it is proposed to produce a synthesis gas raw material by supplying a hydrocarbon compound in the solid state.

Republic of Korea Patent No. 10-0375423 discloses a soot removal technology using a microwave plasma.

In addition, the Republic of Korea Patent No. 10-1475822 relates to a large-capacity electromagnetic plasma torch, a technique that can provide a large-capacity plasma torch to solve the problem of plasma volume limited to a specific frequency which is a disadvantage of the conventional plasma torch disclosed It is.

However, the conventional electromagnetic plasma torch has a problem that is limited to only the TE ₁₀ mode or the TE ₂₀ mode, which is a dominant mode.

(Prior art document)

(Patent literature)

Republic of Korea Patent Publication No. 10-1475822 (2014. 12. 17)

In order to solve the problems as described above, the present invention can be variously plasma treatment in the rectangular waveguide (TE ₁₀ mode), circular resonator (TM _0m0 mode), circular waveguide (TM ₀₁ mode), coaxial resonator (TEM mode) mode In particular, an object of the present invention is to provide an electromagnetic plasma torch that enables natural plasma ignition in a coaxial resonator (TEM mode) mode.

Electromagnetic plasma torch according to the present invention for achieving the above object; A microwave generator for transmitting microwaves to the plasma generator; And a plasma source gas injection unit for injecting a plasma source gas into the plasma generation unit. A microwave transmission line for transmitting microwaves to the plasma generator; And a circular resonator provided in the plasma generation unit, provided at the end of the microwave transmission line of the TE ₁₀ mode to induce a magnetic field, and converting the induced magnetic field into a TM _0m0 mode inducing an electric field in the center to generate a plasma. It is characterized by including.

Electromagnetic plasma torch according to the present invention is capable of natural ignition has the effect of eliminating the trouble of maintenance, such as electrode replacement and electrode contamination removal by the generation of electrodeless plasma.

1 is a block diagram of an electromagnetic plasma torch according to the present invention;

2 is a view related to the electromagnetic plasma torch of the first embodiment according to the present invention;

3 is a view related to electromagnetic plasma torch of a second embodiment according to the present invention;

4 is a view related to an electromagnetic plasma torch of a third embodiment according to the present invention, and

5 is a view related to the electromagnetic plasma torch of the fourth embodiment according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own inventions. Based on the principle that it can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a block diagram of an electromagnetic plasma torch according to the present invention.

For reference, reference is made to Korean Patent Publication No. 10-1475822, which is a previous registered patent of the present inventors with respect to the plasma torch device.

As shown in FIG. 1, the electromagnetic plasma torch according to the present invention includes a power supply unit 100, a microwave generation unit 200, a microwave transmission line (waveguide) 300, a plasma generation unit 400, and a material supply unit. 500, a plasma source gas injection unit 600, a reaction unit 700, and an ignition unit 800.

The power supply unit 100 is composed of a full-wave voltage multiplier, a pulse and direct current (DC) device is configured to supply power to the microwave generator 200.

The microwave generator 200 receives the power from the power supply unit 100, a magnetron for oscillating electromagnetic waves of the 10MHz to 10GHz band is used. Preferably, the microwave generator 200 oscillates 915MHz and 2.45GHz electromagnetic waves.

The microwave transmission line 300 is a waveguide, and is configured to transmit the microwaves oscillated by the microwave generator 200 to the plasma generator 400.

The plasma generator 400 is installed to penetrate the end of the microwave transmission line 300 to provide a space in which plasma is generated by electromagnetic waves input through the microwave transmission line 300 which is a waveguide. In this case, preferably, the plasma generator 400 vertically penetrates the waveguide 300.

The plasma generating unit 400 optionally includes one or more of the configurations of the circular resonator 410, the circular waveguide 420, and / or the coaxial resonator 430, which will be described later. As it is.

The material supply unit 500 is a component for supplying a reaction material for removing fuel reforming, syngas production, and soot by reacting with the plasma generated by the plasma generating unit 400.

The plasma source gas injection unit 600 is configured to inject a plasma source gas into the plasma generator 150 in a swirl form.

The reaction unit 700 is a configuration in which the plasma source gas and the reaction material supplied by the material supply unit 500 react with the plasma generation of the plasma generation unit 400.

The ignition unit 800 is disposed to ignite at a peak portion of the electric field distribution in the discharge tube included in the plasma generator 400.

In the above-described configuration, microwaves pass through the microwave transmission line 300 so that an electric field is distributed at an end portion thereof. When the microwaves pass through a rectangular waveguide, as shown in the left side of FIG. Likewise, the dominant mode TE ₁₀ electric field is formed.

As described above, the dominant mode TE ₁₀ electric field has the strongest electric field in the center of the plasma generating unit 400 and the strength of the electric field decreases as it goes around the discharge tube. There is a problem that the workpiece is pushed around the discharge tube.

In other words, it was difficult to inject the object, and therefore, there was always difficulty in the treatment.

In order to solve the problems and difficulties described above, the electromagnetic plasma torch according to the present invention may include only the circular resonator 410 as shown in FIG. 1 or 2.

When the electromagnetic wave of TE ₁₀ mode is transmitted to the plasma generator 400 through the microwave transmission line 300, which is a rectangular waveguide, the circular resonator 410 constituting the plasma generator 400 is used by the circular resonator 410. _The mode is _switched to _0m0 .

That is, as shown in FIG. 2 (d), the TE ₁₀ mode electric field induces a magnetic field in the circular resonator 410, and the induced magnetic field induces a strong electric field in the center of the circular resonator 410. .

As a result, when ignited by the external ignition unit 800 shown in FIG. 1, the plasma generator 400 generates plasma by the induced strong electric field.

The plasma source gas injection unit 600 is provided at a lower end of the circular resonator 410, and a discharge tube communicating with the circular resonator 410 is provided. The plasma source gas is injected into the discharge tube in the form of swirl.

In this case, when the microwave of TE ₁₀ mode enters the circular resonator 410 at a frequency of 2.45 GHz through the microwave transmission line 300, the resonance frequency is higher than 2.45 GHz due to the discharge tube dielectric constant inside the circular resonator 410. Becomes small.

Therefore, in this case, the diameter D _f of the circular resonator 410 is preferably smaller than the diameter D ₀ when the resonance frequency of 2.45 GHz to compensate for the smaller resonance frequency.

For reference, more generally, the TE ₁₀ mode electromagnetic wave is converted into TM _0m0 mode (m is a positive integer) by the circular resonator 410 of the plasma generator 400. When m is equal to or greater than the TM ₀₂₀ mode of 2 or more, the electric field exhibits the lowest electric field strength in the central portion, and the electric field intensity is distributed higher toward the outside, that is, the central pressure of the plasma generator 400 is increased. The lowering of the pressure around the circumference solved the problem of the workpiece being pushed around the discharge tube.

As described above, as the electric field is distributed, the plasma generating unit 400 generates the same effect as when it is located in a null line in Korean Patent Publication No. 10-1475822, which is the previous patent of the present inventor. Done.

In another embodiment, as shown in FIG. 1 or 3, the plasma generator 400 further includes a circular waveguide 420 at an output end of the circular resonator 410, and the circular waveguide 420 is formed in the circular shape. The magnetic field output from the resonator 410 is converted into a cylindrical waveguide electric field distribution of TM ₀₁ mode, as shown in FIGS. 3 (c) and 3 (d).

Above all, if the plasma electromagnetic wave generated by the interaction between the TE ₁₀ mode by the microwave transmission line 300 and the TM _0m0 mode by the circular resonator 410 is not absorbed 100%, a loss occurs. When the circular waveguide 420 is installed on the circular resonator 410, the circular waveguide 420 generates plasma without loss.

On the other hand, the circular waveguide 420 may serve as a support for injecting a target material such as a hydrocarbon fuel, material powder, and the like.

At this time, when the maximum power flowing into the microwave transmission line 300 of the TE ₁₀ mode to increase the volume of the plasma has a limit, by installing a separate electromagnetic wave source in the circular waveguide 420 of the TM ₀₁ mode It is preferable to increase the volume by supplying electromagnetic waves and supplying electromagnetic energy of TM ₀₁ mode to the plasma flowing from the circular resonator 410.

In another embodiment, as shown in FIG. 1 or 4, the plasma generator 400 further includes a coaxial resonator 430 on one side of the circular resonator 310, and the coaxial resonator 430. An electric field is generated in an outward direction perpendicular to the center electrode disposed at the center of the coaxial resonator 430, and synthesized with the magnetic field formed in the circular resonator 410.

The electromagnetic wave introduced by the microwave transmission line 300 in the TE ₁₀ mode is primarily as a strong electric field is induced at the tip of the center electrode of the coaxial resonator 430 which is responsible for the coaxial mode, as shown in FIG. 4C. To generate a plasma.

At this time, in the present embodiment, a sufficient discharge voltage is formed by the main microwave generated by the microwave generator 200, thereby enabling natural ignition of the plasma.

On the other hand, as shown in Figure 5b, as the swirl-type gas is supplied through the center electrode disposed in the center of the coaxial resonator 430, the coaxial resonator 430 is a plasma in Embodiment 1 described above Simultaneously performs the function of the plasma source gas injection unit 600 for injecting the source gas in a swirl form.

Plasma is generated inside the circular resonator 410 at the same time as the plasma flows into the circular resonator 410 at the tip of the center electrode of the coaxial resonator 430 due to the strong electric field and the swirl gas in the coaxial mode. 100% is absorbed by the plasma of the circular resonator 410 without going to the coaxial resonator 430.

At this time, since the internal electrode of the coaxial resonator 430 may be damaged by the plasma of the circular resonator 410, it is preferable to leave a predetermined distance.

In addition, since the damage is more severe at the time of high power operation, when a separate electromagnetic wave is introduced into the coaxial mode, the center electrode of the coaxial resonator 430 can be placed far away, so that a separate electromagnetic wave source is installed in the coaxial resonator 430. It is desirable to.

As shown in FIG. 1 or FIG. 5, the plasma generating unit 400 passes through the microwave transmission line 300 and includes a circular resonator 410 at an end thereof. The circular waveguide 420 and the coaxial resonator 430 are both provided at the front and rear ends of the circular resonator 410, respectively.

As mentioned in the coaxial mode described above, as shown in FIG. 5B, the gas flowing into the coaxial line is a gas such as air, steam, oxygen, etc., and the length of the plasma (jet type) is increased by separating the swirl gas. This is to introduce an ignition plasma into the resonator 410.

When the microwave oscillated by the microwave generator 200 is transmitted through the microwave transmission line 300, the coaxial resonator 430 spontaneously ignites by the microwave together with gas injection through the coaxial line. Thus, an ignition plasma is generated, and the main plasma is formed by the reaction material supplied from the material supply unit 500 and the plasma source gas injected from the plasma source gas injection unit 600 by the ignition plasma.

In this case, the circular resonator 410 converts the electric field formed in the dominant mode into a magnetic field, thereby allowing an even distribution of the workpiece.

As described above, although the present invention has been described by means of a limited embodiment and drawings, the present invention is not limited thereto and by those skilled in the art to which the present invention pertains, Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

(Explanation of the sign)

100: power supply

200: microwave generating unit

300: microwave transmission line

400: plasma generating unit

410: circular resonator

420: circular waveguide

430: coaxial resonator

500: material supply unit

600: plasma source gas injection unit

700: reaction part

800: ignition unit

Claims

A plasma generator 400;

A microwave generator 200 for transmitting microwaves to the plasma generator 400; And

A plasma source gas injector 600 for injecting a plasma source gas into the plasma generator 400;

A microwave transmission line 300 for transmitting microwaves to the plasma generator 400; And

TM 0m0 which is provided in the plasma generator 400, is provided at the end of the microwave transmission line 300 of the TE 10 mode to induce a magnetic field, the induced magnetic field induces an electric field in the center to generate a plasma Electromagnetic plasma torch comprising a; circular resonator (410) to convert to mode.
The method of claim 1,

The plasma generator 400

It further includes a coaxial resonator 430 including a central electrode disposed in the center and converts the electromagnetic wave introduced by the TE 10 mode into the coaxial mode for generating a plasma as the electric field is induced at the tip of the center electrode Electromagnetic plasma torch.
The method according to claim 1 or 2,

The plasma generator 400

The circular waveguide 420 of the TM 01 mode is configured such that the plasma generated by the interaction of the TE 10 mode, the TM 0m0 mode, and / or the coaxial mode absorbs electromagnetic waves and thus generates plasma without loss. Electromagnetic plasma torch, further comprising.
The method of claim 1,

The plasma generator 400

Electromagnetic plasma torch, characterized in that for generating a plasma by the electric field induced by ignition by the external ignition unit (800).
The method of claim 2,

The plasma generator 400

Electromagnetic plasma torch, characterized in that the discharge voltage is formed by the main microwave generated by the microwave generator 200 generates a plasma by natural ignition.
The method of claim 3, wherein

The circular waveguide 420 is

An electromagnetic plasma torch, which serves as a support for injecting a target material corresponding to a hydrocarbon fuel and a material powder.
The method of claim 1,

Electromagnetic plasma torch, characterized in that the diameter (D f ) of the circular resonator (410) is formed smaller than the diameter (D 0 ) when the resonance frequency for a particular frequency.
The method of claim 3, wherein

By installing a separate electromagnetic wave source in the circular waveguide 420, the electromagnetic wave is further introduced, and the electromagnetic wave plasma of the TM 01 mode is supplied to the plasma flowing from the circular resonator 410 to expand the volume. torch.
The method of claim 2,

The coaxial resonator 430 is

Electromagnetic plasma torch, characterized in that simultaneously performing the function of the plasma source gas injection unit 600 for injecting a plasma source gas in the form of swirl.
The method of claim 9,

The coaxial resonator 430 is

Electromagnetic plasma torch, characterized in that the ignition plasma is introduced into the circular resonator (410) by lengthening the length of the plasma (jet type) separately from the swirl gas.
The method of claim 2,

Electromagnetic plasma torch, characterized in that the plasma generated at the tip of the center electrode of the coaxial resonator 430 is introduced into the circular resonator (410), the electromagnetic wave is all absorbed by the plasma of the circular resonator (410).
The method according to claim 1 or 3,

The TM 0m0 transformed by the circular resonator 410 Wherein in the mode m is a positive integer.