Plasma processing device

Abstract

The present invention addresses the problem of providing a plasma processing device for performing plasma processing on a fluid, the device being capable of suppressing adhesion of a by-product to an electrode portion and suppress deterioration of plasma processing efficiency. As a means for solving the problem, a plasma irradiation device 100 according to the present invention is a plasma processing device 100 for performing plasma processing on a fluid. The plasma processing device 100 comprises an electrode part 20 provided with one or more electrodes 20a and one or more other electrodes 20b facing the one or more electrodes 20a, a fluid supply part 30 for supplying the fluid toward the electrode part 20, and a liquid supply part 40 for supplying a liquid to the electrode part 20, and is configured to be capable of performing both application of a voltage to the electrode part 20 and supply of the liquid to the electrode part 20 by the liquid supply part 40.

Description

Plasma processing equipment

[0001] The present invention relates to a plasma processing apparatus for plasma processing of a fluid, and more particularly to a structure for achieving maintenance of an electrode unit having one or more opposing electrodes and for achieving effective plasma processing.

[0002] In recent years, an apparatus has become known that decomposes organic matter in a gas through plasma treatment using atmospheric pressure plasma generated between electrodes, as disclosed in Patent Document 1.

[0003] International Publication No. 2004 / 112940

[0004] However, when the plasma processing apparatus described in Patent Document 1 is used, the organic matter in the gas is decomposed by the plasma processing, and the by-products generated as a result adhere to the electrodes, resulting in a problem of reduced efficiency of the plasma processing.

[0005] An object of the present invention is to provide a plasma processing apparatus that performs plasma processing on a fluid, and that can prevent by-products from adhering to an electrode portion and prevent a decrease in plasma processing efficiency.

[0006] The present invention provides the following items.

[0007] (Item 1) A plasma processing apparatus for plasma processing a fluid, comprising: an electrode section including one or more first electrodes and one or more second electrodes facing the one or more first electrodes, a fluid supply section that supplies the fluid toward the electrode section, and a liquid supply section that supplies a liquid to the electrode section, wherein the plasma processing apparatus is configured to be able to apply a voltage to the electrode section and also to supply the liquid to the electrode section by the liquid supply section. (Item 2) The plasma processing apparatus according to item 1, which is configured to be able to operate the application of a voltage to the electrode section and the supply of the liquid by the liquid supply section independently and / or in an associated manner.

[0008] (Item 3) The plasma processing apparatus according to item 1, further comprising: a plasma processing unit including the electrode unit; wherein the plasma processing unit includes a reservoir unit that stores the liquid supplied to the electrode unit.

[0009] (Item 4) The plasma processing apparatus according to item 3, wherein at least one of the one or more first electrodes and the one or more second electrodes is partially immersed in the liquid in the reservoir.

[0010] (Item 5) The plasma processing apparatus according to item 3, wherein the liquid supply unit is configured to be able to supply the liquid in the reservoir unit to the electrode unit again.

[0011] (Item 6) The plasma processing apparatus according to item 1, wherein the electrode surfaces of the one or more first electrodes and the one or more second electrodes are inclined with respect to the vertical direction.

[0012] (Item 7) The plasma processing apparatus according to claim 1, further comprising a catalyst portion that holds a catalyst for a component in the fluid.

[0013] (Item 8) The plasma processing apparatus according to any one of items 1 to 7, wherein the fluid is a gas, and the plasma processing is atmospheric pressure plasma processing.

[0014] According to the present invention, a plasma processing apparatus for plasma processing a fluid is obtained that can suppress adhesion of by-products to an electrode portion and suppress a decrease in plasma processing efficiency.

[0015] 1A and 1B are diagrams showing a plasma processing apparatus 100 and a plasma processing apparatus 110 according to a first embodiment of the present invention, respectively;

[0016] The present invention will be described below.Unless otherwise specified, it should be understood that the terms used in this specification are used in the meanings generally used in the relevant field.Therefore, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention belongs.In the event of any discrepancy, this specification (including definitions) shall prevail.

[0017] In this specification, the term "about" refers to a range of ±10% of the following number.

[0018] In the present invention, the "vertical direction" refers to a direction perpendicular to the ground surface or the surface on which the device is placed.

[0019] The present invention aims to provide a plasma processing apparatus that can suppress adhesion of by-products to an electrode section and suppress a decrease in plasma processing efficiency in a plasma processing apparatus that plasma processes a fluid, and solves the above problem by providing a plasma processing apparatus that plasma processes a fluid, the plasma processing apparatus comprising: an electrode section having one or more first electrodes and one or more second electrodes facing the one or more first electrodes; a fluid supply section that supplies the fluid toward the electrode section; and a liquid supply section that supplies a liquid to the electrode section, and is configured to be able to apply a voltage to the electrode section and also to supply the liquid to the electrode section by the liquid supply section.

[0020] Therefore, the plasma processing apparatus of the present invention is not particularly limited as long as it is equipped with an electrode section, a fluid supply section, and a liquid supply section, and is configured to be able to apply a voltage to the electrode section and supply the liquid to the electrode section by the liquid supply section.

[0021] The fluid supplied to the fluid supply unit can be selected depending on the purpose of the plasma treatment, and may be, for example, a gas such as contaminated air or oxygen, a liquid such as contaminated water, or soot.

[0022] The shape and material of the electrodes may be any shape. For example, the shape may be a plate, a cylindrical body such as a cylinder, or a comb shape. However, the present invention is not limited to these. The material of the electrodes may be any material. For example, tungsten, titanium, stainless steel, or other materials that are less susceptible to corrosion than iron, aluminum, or the like may be used.

[0023] Furthermore, various liquids may be used as the liquid supplied to the liquid supply unit. For example, the liquid may be water, a cleaning liquid containing a component that can promote cleaning of by-products generated on the electrode unit, or a liquid containing a component that easily generates plasma. Furthermore, the liquid may be a combination of these components.

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] First Embodiment FIG. 1 is a diagram showing a plasma processing apparatus 100 according to a first embodiment of the present invention.

[0026] The plasma processing apparatus 100 includes a plasma processing unit 100a that performs plasma processing of a fluid. The plasma processing unit 100a includes an electrode unit 20 to which a voltage is applied. The electrode unit 20 includes one or more first electrodes 20a and one or more second electrodes 20b that face the one or more first electrodes 20a. In the electrode unit 20, a dielectric (e.g., glass, resin, etc.) may be disposed between the first electrode 20a and the second electrode 20b. In the embodiment of FIG. 1 , the dielectric is held by the first electrode 20a, but this is not limited thereto. The dielectric may be held by the second electrode 20b, or may be disposed at a position between the first electrode 20a and the second electrode 20b and spaced apart from the first electrode 20a and the second electrode 20b.

[0027] The plasma processing unit 100a includes a housing 10, and an electrode unit 20 is disposed within the housing 10. The electrode unit 20 is connected to a power supply unit 20c capable of applying a voltage between one electrode 20a and the other electrode 20b. The power supply unit 20c may be provided within the plasma processing unit 100, or may be provided as a separate device from the plasma processing unit 100. The plasma processing unit 100 is configured such that a corona discharge capable of atmospheric pressure plasma processing is generated by applying a high voltage from the power supply unit 20c between one or more of the one electrodes 20a and one or more of the other electrodes 20b that constitute the electrode unit 20.

[0028] The electrode surfaces of the electrode unit 20 (the electrode surface of one electrode 20a and the electrode surface of the other electrode 20b) are inclined with respect to the vertical direction N of the ground or the device. In the embodiment shown in Fig. 1, the electrode surface of one electrode 20a and the electrode surface of the other electrode 20b are each inclined with respect to the vertical direction N at an inclination angle α of approximately 30°.

[0029] The plasma processing apparatus 100 also includes a fluid supply unit 30 that supplies a fluid F for plasma processing toward the electrode unit 20, and a liquid supply unit 40 that supplies a liquid to the electrode unit 20. The fluid supply unit 30 includes a supply pipe (not shown) for supplying the fluid F to the plasma processing unit 100a (specifically, the housing 10). Furthermore, the fluid supply unit 30 may include an air blower or other blower.

[0030] The liquid supply unit 40 includes a supply pipe 40a that delivers liquid from a liquid supply source (not shown) and one or more outlets 40b that communicate with the supply pipe 40a and spray the liquid toward the electrode unit 20 (specifically, one or more first electrodes 20a and one or more second electrodes 20b). Furthermore, the liquid supply unit 40 may include a circulation unit (e.g., a circulation pump 40c and a circulation supply pipe 40d in FIG. 1 ) that resupplies the liquid contained in the storage unit 10a (described later) after being supplied to the electrode unit 20 (in the embodiment of FIG. 1 , the liquid that comes into contact with the electrode unit 20 and flows down from the electrode unit 20) to the electrode unit 20. The liquid in the storage unit 10a is configured to be sprayed from one or more outlets 40b by the circulation unit. The circulation unit may further include a filter or the like that removes impurities, such as by-products, from the liquid.

[0031] The plasma processing unit 100a (specifically, the lower part of the housing 10) has a storage unit 10a that stores the liquid supplied from the liquid supply unit 40 to the electrode unit 20 (in the embodiment of FIG. 1, the liquid that comes into contact with the electrode unit 20 and flows down from the electrode unit 20). One electrode 20a is disposed in a position where at least a portion of it is immersed in the liquid stored in the storage unit 10a. However, the present invention is not limited thereto. For example, at least one of the one electrode 20a and the other electrode 20b may be disposed so as to be partially immersed in the liquid in the storage unit 10a, or at least a portion of the other electrode 20b, in addition to the one electrode 20a, may be disposed so as to be immersed in the liquid in the storage unit 10a.

[0032] Furthermore, the plasma processing apparatus 100 includes a plasma processing unit 100a (hereinafter also referred to as the "first processing unit 100a") and a second processing unit 100b that processes components in the fluid F outside the first processing unit 100a. In the embodiment shown in FIG. 1, the second processing unit 100b includes a housing 11. Hereinafter, the housing 10 included in the first processing unit 100a will also be referred to as the "first housing 10," and the housing 11 included in the second processing unit 100b will also be referred to as the "second housing 11." The second processing unit 100b also includes a liquid supply unit 41 (a second supply pipe 41a and a second outlet 41b shown in FIG. 1) that supplies liquid to the inside. Hereinafter, the liquid supply unit 40 included in the first processing unit 100a will also be referred to as the "first liquid supply unit 40," and the liquid supply unit 41 included in the second processing unit 100b will also be referred to as the "second liquid supply unit 41." The second processing unit 100b (specifically, the lower part of the second housing 11) has a reservoir 11a that stores the liquid (in the embodiment of FIG. 1 , the liquid that comes into contact with the electrode unit 20 and flows down from the electrode unit 20) supplied from the second liquid supply unit 41 to the electrode unit 20. The plasma processing apparatus 100 may also have a fluid communication path 50 that allows the fluid F to pass between the first housing 10 and the second housing 11. The plasma processing apparatus 100 may also have a liquid communication path 51 that communicates with the reservoir 10a of the first processing unit 100a and the reservoir 11b of the second processing unit 100b. In the embodiment shown in FIG. 1 , the liquid communication path 51 is configured to allow the liquid to be supplied from the reservoir 11b of the second processing unit 100b to the reservoir 10a of the first processing unit 100a.

[0033] A catalyst unit 70 holding an arbitrary catalyst may be disposed in the second processing unit 100b (specifically, inside the second housing 11). In this case, the second liquid supply unit 41 may be configured to be able to supply a liquid to the catalyst unit 70. The catalyst unit 70 is configured to process (e.g., decompose components in) the fluid F (in the embodiment of FIG. 1 , the fluid F supplied from the electrode unit 20 side).

[0034] The catalyst held in the catalyst unit 70 is not particularly limited, and any catalyst may be used as long as it has the function of decomposing ozone and further removing impurities from the plasma-treated fluid F. For example, the catalyst may be a photocatalyst or a physical catalyst such as manganese dioxide. Note that if the catalyst is a photocatalyst, the second liquid supply unit 41 is not necessary, and instead a light irradiation means is provided.

[0035] By supplying the liquid from the second liquid supply section 41 to the catalyst section 70 (by flowing it over in the embodiment of Figure 1), it is possible to remove impurities adhering to the catalyst section 70, thereby preventing a decrease in the processing efficiency of the catalyst section 70 and making it possible to maintain a constant processing efficiency.

[0036] 1, the processing surface of the catalyst unit 70 is inclined at an angle β of approximately 30° with respect to the vertical direction N of the ground surface or the device mounting surface. This facilitates contact between the liquid supplied from the second liquid supply unit 41 and the catalyst unit 70, making it possible to effectively remove impurities and the like. The angle β may be any angle.

[0037] Alternatively, only the second liquid supply unit 41 may be provided without providing the catalyst unit 70. By supplying the liquid from the second liquid supply unit 41 to the inside of the second processing unit 100b, the components in the fluid F inside the second processing unit 100b (specifically, inside the second housing 11) can be transferred (e.g., dissolved) into the liquid, and the components in the fluid F can be removed.

[0038] The second liquid supply section 41 may have a supply pipe 41a that delivers liquid from a liquid supply source (not shown) or a storage section 10a of the first processing section 100a, and one or more outlets 41b that are connected to the supply pipe 41a and spray the liquid.

[0039] 1, the second processing unit 100b includes a second housing 11, and the catalyst unit 70 is disposed in the second housing 11. However, the present invention is not limited to this. The catalyst unit 70 may be disposed at a position inside the first housing 10 where the fluid F passes through the electrode unit 20.

[0040] Furthermore, the plasma processing apparatus 100 has a control unit that can operate the fluid supply unit 30, the power supply unit 20c, and the liquid supply unit 40 independently and / or in association with each other. However, the present invention is not limited to this. The plasma processing apparatus 100 may not have a control unit and each unit may be manually operated independently.

[0041] Next, the operation and effects of the plasma processing apparatus 100 will be described.

[0042] The fluid F to be plasma-treated is supplied toward the electrode unit 20 by the fluid supply unit 30 of the plasma processing unit 100a. A high voltage is applied to the electrode unit 20 (specifically, between one or more first electrodes 20a and one or more second electrodes 20b) by the power supply unit 20c. This generates a corona discharge in the electrode unit 20, enabling atmospheric pressure plasma treatment. In addition, while the voltage is applied to the electrode unit 20, a liquid is supplied to the electrode unit 20 by the liquid supply unit 40. In this state, the fluid F supplied into the plasma processing unit 100a (in the embodiment of FIG. 1, the housing 10) is plasma-treated by passing through the electrode unit 20. During this process, organic matter in the fluid F is decomposed by the plasma treatment, generating by-products. However, since the liquid supply unit 40 supplies the liquid to the electrode unit 20 in conjunction with the plasma treatment, adhesion of the by-products to the electrode unit 20 (in the embodiment of FIG. 1, at least one of the one or more first electrodes 20a, the one or more second electrodes 20b, and the dielectric) can be suppressed. As a result, the efficiency of the plasma processing can be maintained.

[0043] Furthermore, in addition to the discharge between one or more of the first electrodes 20a and one or more of the second electrodes 20b, a corona discharge also occurs in the electric field generated between the surface of the liquid attached to the electrode unit 20 (in the embodiment of FIG. 1, at least one of the portion composed of one or more of the first electrodes 20a, one or more of the second electrodes 20b, and the dielectric) and at least one of the electrodes 20a, 20b, making it possible to perform plasma treatment more effectively than plasma treatment based solely on discharge between the electrodes. The applicant was the first to discover this effect.

[0044] Furthermore, by constantly supplying (flowing in the embodiment of FIG. 1 ) liquid from the liquid supply unit 40 to the electrode unit 20 during plasma processing, it is possible to suppress a rise in temperature of the electrode unit 20 (one or more first electrodes 20 a, one or more second electrodes 20 b), and maintain good plasma processing (ability to decompose organic matter in the fluid F). In addition, the generation of steam can further improve the efficiency of decomposing organic matter.

[0045] Furthermore, since the electrode surfaces of the electrode unit 20 (the electrode surface of one electrode 20a and the other electrode 20b) are inclined with respect to the vertical direction N of the ground or the device, the liquid supplied from the liquid supply unit 40 provided above easily comes into contact with the electrode unit 20, and adhesion of by-products and the like to the electrode unit 20 can be more effectively suppressed.

[0046] Then, the fluid F that has passed through the plasma treatment section 100a as the first treatment section 100a moves to the second treatment section 100b through the fluid communication passage 50, and comes into contact with the catalyst section 70 and / or the liquid supplied by the second liquid supply section 41. This allows components in the fluid F, such as ozone, to be further removed (for example, by decomposition treatment or dissolution into liquid).

[0047] Second Embodiment FIG. 2 is a diagram showing a plasma processing apparatus 110 according to a second embodiment of the present invention.

[0048] The plasma processing apparatus 110 of this embodiment 2 is different from the configuration of the plasma processing apparatus 100 of embodiment 1 in the arrangement of one or more electrode surfaces of one electrode 20 a, one or more electrode surfaces of the other electrode 20 b, the processing surface of the catalyst unit 70, and the second liquid supply unit 41, but is otherwise the same in configuration as the plasma processing apparatus 100 of embodiment 1. Note that reference numerals for components that are the same are omitted.

[0049] In the embodiment of Figure 2, the electrode surfaces of one or more of the first electrodes 21a, the electrode surfaces of one or more of the second electrodes 21b, the processing surface of the catalyst unit 70a, and the multiple outlets 42b of the second liquid supply unit 41 may be arranged approximately vertically with respect to the ground surface or the surface on which the device is placed. However, the present invention is not limited to this. For example, the electrode surfaces of one or more of the first electrodes 21a and one or more of the second electrodes 21b and / or the processing surface of the catalyst unit 70a may be arranged approximately horizontally with respect to the ground surface or the surface on which the device is placed.

[0050] As described above, the present invention has been illustrated using preferred embodiments of the present invention, but the present invention should not be construed as being limited to these embodiments. It is understood that the scope of the present invention should be interpreted only by the claims. It is understood that a person skilled in the art can implement an equivalent scope based on the description of the present invention and common general technical knowledge from the description of specific preferred embodiments of the present invention. It is understood that the contents of the documents cited in this specification should be incorporated by reference into this specification as if the contents themselves were specifically set forth in this specification.

[0051] The present invention is useful in that it can provide a plasma processing apparatus that performs plasma processing on a fluid, and that can suppress adhesion of by-products to an electrode portion and suppress a decrease in plasma processing efficiency.

[0052] REFERENCE SIGNS LIST 100, 110 Plasma processing apparatus 100a Plasma processing section (first processing section) 100b Second processing section 10 Housing 10a Storage section 20 Electrode section 20a One electrode 20b Other electrode 20c Power supply section 30 Fluid supply section 40 Liquid supply section 50 Processing fluid communication path 51 Liquid communication path 70 Catalyst section F Fluid N Vertical direction

Claims

1. A plasma processing apparatus for plasma processing a fluid, comprising: an electrode section having one or more first electrodes and one or more second electrodes facing the one or more first electrodes; a fluid supply section that supplies the fluid toward the electrode section; and a liquid supply section that supplies liquid to the electrode section, and is configured to be able to apply a voltage to the electrode section and to supply the liquid to the electrode section by the liquid supply section.

2. The plasma processing apparatus according to claim 1, wherein the application of voltage to the electrode section and the supply of the liquid by the liquid supply section can be operated independently and / or in association with each other.

3. The plasma processing apparatus according to claim 1, further comprising a plasma processing section including the electrode section, wherein the plasma processing section includes a reservoir section for storing the liquid supplied to the electrode section.

4. The plasma processing apparatus according to claim 3, wherein at least one of the one or more first electrodes and the one or more second electrodes is partially immersed in the liquid in the reservoir.

5. The plasma processing apparatus according to claim 3, wherein the liquid supply section is configured to be able to supply the liquid in the reservoir section again to the electrode section.

6. The plasma processing apparatus according to claim 1, wherein the electrode surfaces of the one or more first electrodes and the one or more second electrodes are inclined with respect to the vertical direction.

7. The plasma processing apparatus according to claim 1, further comprising a catalyst portion for holding a catalyst for a component in the fluid.

8. The plasma processing apparatus according to any one of claims 1 to 7, wherein the fluid is a gas and the plasma processing is atmospheric pressure plasma processing.

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