Gas reforming device

Abstract

The gas reforming apparatus (100) includes a reaction vessel (2) having a first reaction chamber (41) into which a gas to be reformed (G1) flows, and a second reaction chamber (42) into which the gas to be reformed (G1) that has passed through the first reaction chamber (41) flows and which is thermally partitioned from the first reaction chamber (41), first and second electrodes (31, 32) provided in the first reaction chamber (41) for generating plasma (P) in the first reaction chamber (41), a lead-out electrode (33) provided in the second reaction chamber (42) for leading the plasma (P) from the first reaction chamber (41) into the second reaction chamber (42), and a reaction accelerator (7) disposed on the lead-out electrode (33).

Description

Technical Field

[0001] The present disclosure relates to a gas reforming device.

Background Art

[0002] A plasma reactor is known in which a gas to be reformed is reacted with plasma to reform the gas to be reformed into a substance with added value (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a gas reforming device that generates plasma to reform a gas to be reformed, it has been required to obtain more reformed gas with respect to the amount of energy input to the gas reforming device.

[0005] The invention according to the present disclosure has been made in view of the above circumstances, and an object thereof is to provide a gas reforming device capable of efficiently reforming a gas to be reformed.

Means for Solving the Problems

[0006] The gas reforming device according to the present disclosure A gas reforming apparatus that generates plasma to reform a gas to be reformed, said a reaction vessel including a first reaction chamber into which a gas to be reformed flows, and a second reaction chamber into which the gas to be reformed that has flowed through the first reaction chamber flows and that is thermally partitioned from the first reaction chamber; provided in the first reaction chamber ta a first electrode and a second electrode that is installed so as to partition the first reaction chamber and the second reaction chamber, or is installed in a partition portion that partitions the first reaction chamber and the second reaction chamber, and generates plasma with the first electrode; A draw-out electrode provided in the second reaction chamber, which draws out the plasma from the first reaction chamber into the second reaction chamber due to the potential difference with the second electrode, a reaction accelerator that promotes the reforming reaction of the gas to be reformed by the plasma, and the reaction accelerator is disposed on the extraction electrode.

Advantages of the Invention

[0007] According to the gas reforming device according to the present disclosure, the gas to be reformed can be efficiently reformed.

Brief Description of the Drawings

[0008]

Figure 1

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, the gas reforming apparatus according to the embodiment of the present disclosure will be described with reference to the drawings. Note that each of the following drawings is schematically illustrated, and the dimensional ratios and the number of components on the drawings do not necessarily match the actual dimensional ratios and the number of components.

[0010] Embodiment 1. The configuration of the gas reforming apparatus 100 according to Embodiment 1 will be described with reference to FIGS. 1 to 4. FIGS. 1 to 4 are drawings schematically showing the configuration of the gas reforming apparatus 100 according to Embodiment 1. FIG. 2 is a cross-sectional view of the A-A portion shown in FIG. 1. FIG. 3 is a cross-sectional view of the B-B portion shown in FIG. 1. FIG. 4 is a drawing schematically showing another configuration example of the power supply circuit in the gas reforming apparatus 100 shown in FIG. 1.

[0011] As shown in FIG. 1, the gas reforming apparatus 100 includes a reaction vessel 2 including a first reaction chamber 41 into which the gas to be reformed G1 flows and a second reaction chamber 42 into which the gas to be reformed G1 that has passed through the first reaction chamber 41 flows, a first electrode 31 and a second electrode 32 provided in the first reaction chamber 41 and generating plasma P in the first reaction chamber 41, a third electrode 33 which is a drawing electrode provided in the second reaction chamber 42 and drawing the plasma P from the first reaction chamber 41 into the second reaction chamber 42, and a reaction accelerator 7 disposed on the third electrode 33 which is a drawing electrode.

[0012] Here, in this specification, the direction in which the first reaction chamber 41 and the second reaction chamber 42 face each other is defined as the Z-axis, and the plane orthogonal to the Z-axis is defined as the XY plane. In the following description, the XYZ coordinate system defined in this way will be referred to as appropriate. In this specification, when expressing a direction and distinguishing between positive and negative directions, it is described with positive and negative signs, such as the "+Z direction" and the "-Z direction". When expressing a direction without distinguishing between positive and negative directions, it is simply described as the "Z direction". That is, in this specification, when simply described as the "Z direction", both the "+Z direction" and the "-Z direction" are included. In the present embodiment, the direction from the first reaction chamber 41 to the second reaction chamber 42 is the -Z direction.

[0013] The shape of the reaction vessel 2 is an axisymmetric shape with the Z1-axis shown in FIG. 1 as the axis of symmetry. In the present embodiment, the Z1-axis is parallel to the Z-axis. Specifically, the shape of the reaction vessel 2 is, for example, a cylindrical shape having end faces at both ends. However, the shape of the reaction vessel 2 is not particularly limited as long as it is a hollow vessel, and it is not essential to have an axisymmetric shape and a symmetric structure.

[0014] The material constituting the reaction vessel 2 is not particularly limited, but a material with high insulation and durability is preferred. Specifically, the reaction vessel 2 is preferably made of glass or ceramics. Specific examples of the glass constituting the reaction vessel 2 include quartz glass and borosilicate glass. Further, specific examples of the ceramics constituting the reaction vessel 2 include alumina (Al2O3), zirconia (ZrO2), and magnesia (MgO).

[0015] As shown in FIG. 1, the reaction vessel 2 is provided with a gas inlet 51 for flowing the gas to be reformed G1 into the first reaction chamber 41. The position where the gas inlet 51 is provided is not particularly limited as long as the gas to be reformed G1 can flow into the first reaction chamber 41. Also, the gas inlet 51 may be provided at a plurality of locations. In the present embodiment, the gas inlet 51 is provided at one location on the end face on the +Z direction side of the reaction vessel 2.

[0016] As shown in Fig. 1, the reaction vessel 2 is provided with a gas outlet 53 for allowing the reformed gas G2 to flow out from the second reaction chamber 42. The position where the gas outlet 53 is provided is not particularly limited as long as the reformed gas G2 can flow out from the second reaction chamber 42. Further, the gas outlet 53 may be provided at a plurality of locations. In the present embodiment, one gas outlet 53 is provided at the end face on the -Z direction side of the reaction vessel 2.

[0017] As shown in Fig. 1, a first electrode 31 is disposed on the end face of the reaction vessel 2 on the side in the direction from the second reaction chamber 42 toward the first reaction chamber 41 (+Z direction). Further, since the first electrode 31 is exposed in the first reaction chamber 41, it can be said that the first electrode 31 is provided in the first reaction chamber 41.

[0018] As shown in Figs. 1 and 2, the shape of the first electrode 31 is cylindrical. However, the shape of the first electrode 31 is not limited to this.

[0019] The first electrode 31 is made of a conductive material. Specific examples of the material constituting the first electrode 31 include stainless steel, titanium, molybdenum, and tungsten. However, the material constituting the first electrode 31 can be used without being limited to these as long as it is a conductive material having high corrosion resistance and heat resistance.

[0020] As shown in Fig. 1, a second electrode 32 is disposed in the reaction vessel 2 at a position spaced apart in the direction toward the second reaction chamber 42 (-Z direction) when viewed from the first electrode 31. It can also be said that the second electrode 32 is provided in the first reaction chamber 41. The second electrode 32 faces the first electrode 31 in the first reaction chamber 41. The first electrode 31 and the second electrode 32 are electrodes for generating plasma P in the first reaction chamber 41.

[0021] As shown in FIGS. 1 and 2, the shape of the second electrode 32 is disk-shaped. An opening 52 is provided in the second electrode 32. The opening 52 is an opening that connects the first reaction chamber 41 and the second reaction chamber 42. Further, the second electrode 32 is also a member that thermally partitions the first reaction chamber 41 and the second reaction chamber 42. Here, in this specification, "thermally partition" means suppressing heat transfer by heat conduction, convection, or radiation by a certain member or structure, and also includes heat insulation.

[0022] The second electrode 32 is made of a conductive material, similar to the first electrode 31. Since specific examples of the material constituting the second electrode 32 are the same as those of the first electrode 31, the description is omitted. Note that the second electrode 32 may be made of a material different from that of the first electrode 31. For example, the first electrode 31 may be composed of tungsten, and the second electrode 32 may be composed of molybdenum.

[0023] As shown in FIG. 1, a third electrode 33 is provided on the end face of the reaction vessel 2 on the side in the direction (-Z direction) from the first reaction chamber 41 to the second reaction chamber 42. It can also be said that the third electrode 33 is provided in the second reaction chamber 42. The third electrode 33 faces the first electrode 31 through the opening 52. Further, the third electrode 33 faces the second electrode 32 in the second reaction chamber 42.

[0024] As shown in FIGS. 1 and 3, the third electrode 33 has a shape having a tip portion 33a and a shaft portion 33b. In the present embodiment, the shape of the tip portion 33a is disk-shaped. Also, the shape of the shaft portion 33b is cylindrical. However, the shape of the third electrode 33 in the present embodiment is merely an example. For example, the tip portion 33a may have a tapered shape in which the diameter decreases toward the tip. Further, it is not essential for the third electrode 33 to have the tip portion 33a, and the shape of the third electrode 33 may be a cylindrical shape with only the shaft portion 33b.

[0025] The third electrode 33 is made of a conductive material, similar to the first electrode 31. Specific examples of the material constituting the third electrode 33 are the same as those of the first electrode 31, so the description is omitted. Note that the third electrode 33 may be made of a material different from that of the first electrode 31 or the second electrode 32.

[0026] As shown in FIG. 1, on the surface of the tip portion 33a of the third electrode 33 that faces the opening 52, a reaction accelerator 7 is disposed. The reaction accelerator 7 is a substance that promotes the reforming reaction of the gas to be reformed G1 by the plasma P. The reaction accelerator 7 may be provided over the entire surface of the tip portion 33a that faces the opening 52, or may be provided on a part of that surface. Details of the reforming reaction of the gas to be reformed G1 by the plasma P will be described later. The reaction accelerator 7 is selected as an appropriate substance according to the type of the gas to be reformed G1. The reaction accelerator 7 is, for example, a catalyst, a reducing agent, or an oxidizing agent.

[0027] Typical modes of disposing the reaction accelerator 7 on the third electrode 33 are a mode of placing the reaction accelerator 7 on the surface of the third electrode 33 or a mode of attaching it. However, the mode of disposing the reaction accelerator 7 on the third electrode 33 is not limited to these. For example, the reaction accelerator 7 may be disposed on the third electrode 33 by a mode of modifying the surface of the third electrode 33 with a substance containing the reaction accelerator 7. Specifically, for example, when the third electrode 33 is tungsten and the reaction accelerator 7 is carbon as a reducing agent, the third electrode 33 may be carbonized to modify the surface of the third electrode 33 to tungsten carbide. Note that the carbonization treatment is performed, for example, by preparing a solution in which carbon powder is dispersed in a solvent, applying the solution to the surface of the third electrode 33, and then heat-treating the third electrode 33 in an electric furnace or the like.

[0028] As shown in FIG. 1, the first electrode 31 and the second electrode 32 are connected via a first power source 61. The first power source 61 is a DC power source that applies a voltage between the first electrode 31 and the second electrode 32. By applying a predetermined voltage between the first electrode 31 and the second electrode 32, plasma P can be generated inside the first reaction chamber 41.

[0029] The voltage value output by the first power source 61 is appropriately designed according to various conditions so that the plasma P can be stably generated. Conditions considered for designing the voltage value output by the first power source 61 include, for example, the distance between the first electrode 31 and the second electrode 32, the composition of the gas to be reformed G1, the flow rate of the gas to be reformed G1, and the pressure inside the first reaction chamber 41.

[0030] Note that the first power source 61 is not limited to a DC power source. As long as the plasma P can be generated inside the first reaction chamber 41, the first power source 61 may be an AC power source or a pulse power source. When the first power source 61 is an AC power source, the peak value and frequency are appropriately designed according to various conditions, similar to the case where the first power source 61 is a DC power source. Also, when the first power source 61 is a pulse power source, the peak value and duty ratio are appropriately designed according to various conditions, similar to the case where the first power source 61 is a DC power source.

[0031] As shown in FIG. 1, the second electrode 32 and the third electrode 33 are connected via the second power source 62. Also, the third electrode 33 is grounded. The second power source 62 is a DC power source that applies a voltage between the second electrode 32 and the third electrode 33. By applying a predetermined voltage between the second electrode 32 and the third electrode 33, the plasma P generated inside the first reaction chamber 41 can be drawn into the second reaction chamber 42. Therefore, it can be said that the third electrode 33 is an extraction electrode that draws the plasma P generated inside the first reaction chamber 41 into the second reaction chamber 42.

[0032] The voltage value output by the second power source 62 is appropriately designed according to various conditions so that the plasma P generated inside the first reaction chamber 41 can be drawn into the second reaction chamber 42. Conditions considered for designing the voltage value output by the second power source 62 include, for example, the distance between the first electrode 31 and the third electrode 33, the distance between the second electrode 32 and the third electrode 33, the composition of the gas to be reformed G1, the flow rate of the gas to be reformed G1, and the pressure inside the second reaction chamber 42. Also for the second power source 62, an AC power source or a pulse power source can be adopted instead of a DC power source.

[0033] Also, it is not essential for the gas reformer 100 to include the second power source 62. As shown in FIG. 4, the gas reformer 100 may be configured to include a passive element 63 instead of the second power source 62. The passive element 63 is, for example, a resistor or a capacitor.

[0034] In the case of the configuration shown in FIG. 4, due to the actions of the first power source 61 and the passive element 63, a potential difference from the ground potential is generated between the second electrode 32 and the third electrode 33. Then, due to this potential difference, the plasma P is drawn into the second reaction chamber 42.

[0035] By adopting a configuration including the passive element 63 instead of the second power source 62, the configuration of the power supply circuit of the gas reformer 100 can be simplified. By simplifying the configuration of the power supply circuit of the gas reformer 100, the effect of facilitating the maintenance of the gas reformer 100 is achieved.

[0036] In addition, when the lead wire connecting the second electrode 32 and the third electrode 33 generates a potential difference that draws the plasma P into the second reaction chamber 42, the gas reformer 100 may not include the passive element 63. By adopting a configuration omitting the passive element 63, the configuration of the power supply circuit of the gas reformer 100 can be further simplified.

[0037] Next, the operation of the gas reformer 100 according to Embodiment 1 will be described with reference to FIGS. 1 and 5. FIG. 5 is a schematic diagram showing an example of the flow of the gas G1 to be reformed in the gas reformer 100 according to Embodiment 1.

[0038] First, the flow of the gas G1 to be reformed in the gas reformer 100 will be described. As shown in FIG. 5, the gas G1 to be reformed is caused to flow into the first reaction chamber 41 from the gas inlet 51. The gas G1 to be reformed that has flowed through the inside of the first reaction chamber 41 flows into the second reaction chamber 42 from the opening 52 and flows through the inside of the second reaction chamber 42. Then, the gas G2 reformed inside the first reaction chamber 41 and the second reaction chamber 42 flows out from the gas outlet 53.

[0039] Next, the action of the plasma P in the gas reforming device 100 will be described. When a high voltage is applied between the first electrode 31 and the second electrode 32, plasma P is generated inside the first reaction chamber 41. By this plasma P, the gas G1 to be reformed flowing through the inside of the first reaction chamber 41 is reformed. The mechanism of reforming the gas G1 to be reformed by the plasma P will be described later.

[0040] When a high voltage is applied between the second electrode 32 and the third electrode 33, the plasma P generated inside the first reaction chamber 41 is drawn into the inside of the second reaction chamber 42. By this plasma P, the gas G1 to be reformed flowing through the inside of the second reaction chamber 42 is reformed.

[0041] Further, due to the action of the reaction accelerator 7 disposed on the third electrode 33, the reforming reaction of the gas G1 to be reformed by the plasma P is promoted. Here, since the reaction accelerator 7 is disposed on the third electrode 33, it receives heat from the third electrode 33 heated by receiving heat from the plasma P and is heated. Further, since the reaction accelerator 7 is disposed in the second reaction chamber 42 thermally partitioned from the first reaction chamber 41, it is difficult to dissipate heat and the temperature is difficult to decrease. Since the reaction efficiency of the reaction accelerator 7 with the gas G1 to be reformed improves as the temperature increases, according to the gas reforming device 100 according to the present embodiment, the reforming efficiency of the gas G1 to be reformed (the amount of the reformed gas G2 generated with respect to the amount of input energy) is improved.

[0042] Further, since the reaction accelerator 7 is disposed on the side (+Z side) of the third electrode 33 facing the opening 52, it comes into contact with the plasma P. At this time, the reaction accelerator 7 is heated by the heat received from the plasma P and the heat generated by the reforming reaction of the gas G1 to be reformed. By disposing the reaction accelerator 7 so that the plasma P comes into contact with the reaction accelerator 7 in this way, the gas G1 to be reformed can be reformed more efficiently.

[0043] In addition, in the gas reforming apparatus 100 according to the present embodiment, since the reaction accelerator 7 is arranged so that the plasma P comes into contact with the reaction accelerator 7, the energy loss until the molecules excited by the plasma P reach the reaction accelerator 7 is suppressed. In addition, the molecules excited by the plasma P can reach the reaction accelerator 7 before disappearing due to recombination or diffusion. Also by such an action, the reforming efficiency of the gas G1 to be reformed by the plasma P is improved.

[0044] Next, the gas reforming mechanism by the gas reforming apparatus 100 according to Embodiment 1 will be described. Here, a case will be described as an example in which the gas G1 to be reformed is carbon dioxide (CO2), the reaction accelerator 7 is carbon (C), and carbon monoxide (CO) is generated as the reformed gas G2. Note that carbon functions as a reducing agent. In addition, this example is an example when it is assumed that the gas reforming apparatus 100 reforms the gas G1 (CO2) to be reformed into a substance (CO) that can be used as fuel. The gas G1 to be reformed, the reaction accelerator 7, and the reformed gas G2 are not limited to these.

[0045] Due to the high voltage applied between the first electrode 31 and the second electrode 32, the electrons existing in the space in the first reaction chamber 41 are accelerated. At this time, when the molecules of CO2 collide with high-energy electrons, CO is generated by the decomposition reaction of Equation (1). e+CO2→CO+O ‥‥(1)

[0046] Here, in Equation (1), e represents an electron and O represents atomic oxygen. Note that there are a plurality of reaction paths for the decomposition reaction of Equation (1), such as direct dissociation by electrons or dissociation via the vibration excitation level of CO2. However, in Equation (1), these plurality of reaction paths are collectively represented.

[0047] Part of the O generated by the reaction of formula (1) is converted to oxygen (O₂) by combining with another O. Also, part of the O generated by the reaction of formula (1) recombines with CO to be converted to CO₂. Further, part of the CO generated by the reaction of formula (1) is oxidized by the O₂ generated by the reaction of formula (1) and converted to CO₂. Here, since we are trying to generate CO as the reformed gas G2, the conversion of the CO generated by the reaction of formula (1) to CO₂ means a decrease in the efficiency of gas reforming. Therefore, it is desirable that the O generated by the reaction of formula (1) and the O₂ generated by the combination of O's are quickly removed.

[0048] Here, in the gas reforming apparatus 100 according to Embodiment 1, the carbon (C) which is the reaction promoter 7 is disposed on the third electrode 33, and the plasma P contacts the carbon (C) which is the reaction promoter 7. At this time, the O generated by the reaction of formula (1) is removed by the oxidation reaction of formula (2). Also, the O₂ generated by the combination of the O's generated by the reaction of formula (1) is removed by the oxidation reaction of formula (3). C + O → CO ··· (2) C + O₂ → CO₂ ··· (3)

[0049] Also, between C (carbon) and CO₂ and CO, the relationship of the Boudouard equilibrium of formula (4) holds. C + CO₂ ←→ 2CO ··· (4)

[0050] Here, the generation of CO by formula (2) and formula (4) increases as the temperature rises. That is, the reforming efficiency from CO₂ which is the gas to be reformed G1 to CO which is the reformed gas G2 improves as the temperature rises.

[0051] In the gas reforming apparatus 100 according to Embodiment 1, plasma P is drawn into the second reaction chamber 42 by the third electrode 33 which is a draw-out electrode, and the plasma P is brought into contact with carbon (C) which is the reaction accelerator 7. Therefore, regarding O generated from CO2 by the plasma P (refer to Equation (1)), before O recombines with CO, O can be removed by reacting O with carbon (C) which is the reaction accelerator 7 (refer to Equation (2)). That is, according to the gas reforming apparatus 100 according to Embodiment 1, a decrease in the reforming efficiency of the gas to be reformed G1 is prevented.

[0052] Furthermore, in the gas reforming apparatus 100 according to Embodiment 1, since the carbon (C) which is the reaction accelerator 7 is arranged in the second reaction chamber 42 which is thermally partitioned from the first reaction chamber 41, the carbon (C) which is the reaction accelerator 7 can be maintained in a high-temperature state. For the chemical reaction of removing O (Equation (2)) and the chemical reaction of removing O2 (Equation (3)), the higher the temperature, the more activated the reaction. Therefore, by maintaining the carbon (C) which is the reaction accelerator 7 in a high-temperature state, O and O2 which cause a decrease in the efficiency of gas reforming can be removed more effectively. Also, by maintaining the carbon (C) which is the reaction accelerator 7 in a high-temperature state, the generation of CO according to Equation (4) can be promoted more effectively. Therefore, according to the gas reforming apparatus 100 according to Embodiment 1, CO2 can be efficiently reformed into CO.

[0053] Note that the description of gas reforming with the example where the gas to be reformed G1 is CO2 is an explanation of an example of the case where the gas reforming apparatus 100 reforms the gas to be reformed G1 into a substance that can be used as fuel. The gas reforming apparatus 100 can also be used for other applications. For example, the gas reforming apparatus 100 can also be used for applications where a highly harmful substance contained in the gas to be reformed G1 is reformed into a less harmful substance. Specifically, for example, the case of decomposing volatile organic compounds (VOCs) such as toluene or xylene using a catalyst such as platinum (Pt) or palladium (Pd) can be mentioned.

[0054] In addition, the gas reforming device 100 can also be used for the purpose of reforming a gas to be reformed with a high global warming potential into a substance with a low global warming potential. Specifically, for example, nitrous oxide (N2O) can be decomposed into nitrogen (N2) and oxygen (O2) using a catalyst such as platinum (Pt) or palladium (Pd).

[0055] The configuration of the gas reforming device 100 described above is merely an example, and the gas reforming device 100 of the present embodiment can adopt various variations. Hereinafter, the structure in the modification example will be described with reference to the drawings. Note that the description will be omitted or simplified for the points common to the gas reforming device 100 according to the first embodiment. In addition, the same reference numerals are given to the configurations common to the gas reforming device 100 according to the first embodiment.

[0056] Modification example 1. The first modification example of the first embodiment will be described with reference to FIG. 6. FIG. 6 is a cross-sectional view showing the gas reforming device 100 according to the first modification example of the first embodiment.

[0057] The shape of the plasma P formed in the gas reforming device 100 depends on the electric field inside the first reaction chamber 41 and the second reaction chamber 42, and the flow direction of the gas G1 to be reformed inside the first reaction chamber 41 and the second reaction chamber 42.

[0058] As shown in FIG. 6, in the gas reforming device 100 of the first modification example, the first electrode 31 is disposed at a position deviated from the Z1 axis where the third electrode 33 is disposed. In the case of the configuration shown in FIG. 6, the plasma P has a curved shape when viewed in the Y direction. When the shape of the plasma P is curved, the length of the plasma P in the first reaction chamber 41 can be extended compared to the case where it is not curved. And when the length of the plasma P in the first reaction chamber 41 is extended, more of the gas G1 to be reformed comes into contact with the plasma P, so the ratio of the gas G1 to be reformed reformed by the plasma P is increased.

[0059] Modification example 2. Modification Example 2 of Embodiment 1 will be described with reference to FIGS. 7 and 8. FIG. 7 is a cross-sectional view showing a gas reforming apparatus 100 according to Modification Example 2 of Embodiment 1. FIG. 8 is a cross-sectional view of the C-C portion shown in FIG. 7.

[0060] The path of the plasma P generated between the first electrode 31 and the second electrode 32 changes depending on the electric field inside the first reaction chamber 41 and the flow direction of the gas G1 to be reformed inside the first reaction chamber 41. Also, the path of the plasma P generated between the first electrode 31 and the third electrode 33 changes depending on the electric fields inside the first reaction chamber 41 and the second reaction chamber 42 and the flow direction of the gas G1 to be reformed inside the first reaction chamber 41 and the second reaction chamber 42. When the path of the plasma P changes, the contact location with the plasma P may move at each electrode.

[0061] As shown in FIGS. 7 and 8, in the gas reforming apparatus 100 of Modification Example 2, the tip shape of the first electrode 31 is ring-shaped. In this case, compared with the case where the first electrode 31 is cylindrical (see FIGS. 1 and 2), the tip surface of the first electrode 31 extends greatly in a plane (XY plane) perpendicular to the direction in which the first electrode 31 and the second electrode 32 face each other.

[0062] Therefore, for the first electrode 31 with a ring-shaped tip, the movement range of the contact location with the plasma P becomes larger. When the contact location between the first electrode 31 and the plasma P moves greatly, it is possible to prevent the first electrode 31 from being locally heated. By preventing the first electrode 31 from being locally heated, wear and deformation of the first electrode 31 can be suppressed, so that the first electrode 31 can have a longer lifespan.

[0063] Thus, in the gas reforming apparatus 100 of Modification 2, the first electrode 31 can have an extended lifespan, so that the gas reforming apparatus 100 can operate stably over a long period. Also, by extending the lifespan of the first electrode 31, the replacement frequency of the first electrode 31 can be reduced, so that the man-hours for maintenance work of the gas reforming apparatus 100 can be suppressed. Note that the shape of the first electrode 31 in Modification 2 is an example of a modification for extending the lifespan of the first electrode 31. The shape of the first electrode 31 is appropriately designed for the purpose of extending the lifespan or otherwise.

[0064] Modification 3. Modification 3 of Embodiment 1 will be described with reference to FIGS. 9 and 10. FIG. 9 is a cross-sectional view showing the gas reforming apparatus 100 according to Modification 3 of Embodiment 1. FIG. 10 is a cross-sectional view of the D-D portion shown in FIG. 9.

[0065] Regarding Embodiment 1, the case where the opening 52, which is an opening connecting the first reaction chamber 41 and the second reaction chamber 42, is provided in the second electrode 32 has been exemplified and described. However, it is not essential that the opening 52 is provided in the second electrode 32, and the opening 52 may be provided in another component.

[0066] As shown in FIG. 9, in the gas reforming apparatus 100 of Modification 3, the reaction vessel 2 has a structure having a partition portion 21 that partitions the first reaction chamber 41 and the second reaction chamber 42. The partition portion 21 is provided with an opening 52, which is an opening connecting the first reaction chamber 41 and the second reaction chamber 42. Also, the second electrode 32 is disposed on the surface of the partition portion 21 facing the first electrode 31 (the surface on the +Z direction side). Also, as shown in FIG. 10, the second electrode 32 is composed of four rectangular flat plates.

[0067] The material constituting the partition portion 21 is not particularly limited. Since the second electrode 32 is attached to the partition portion 21, the material constituting the partition portion 21 is preferably a material that is easy to process. Further, the material constituting the partition portion 21 is preferably a material having good durability against the plasma P. The partition portion 21 is constituted by, for example, ceramics such as alumina (Al2O3), zirconia (ZrO2), and magnesia (MgO).

[0068] In the gas reforming apparatus 100 of Modification 3, the partition portion 21 functions as a member that thermally partitions the first reaction chamber 41 and the second reaction chamber 42.

[0069] Note that the shape of the second electrode 32 may be a ring shape, and an opening portion 52, which is an opening connecting the first reaction chamber 41 and the second reaction chamber 42, may be provided in both the second electrode 32 and the partition portion 21. In this case, both the partition portion 21 and the second electrode 32 function as members that thermally partition the first reaction chamber 41 and the second reaction chamber 42.

[0070] Further, in the gas reforming apparatus 100 of Modification 3, since the second electrode 32 is provided on the partition portion 21, the second electrode 32 can be easily replaced when the second electrode 32 is consumed or deformed. According to the gas reforming apparatus 100 of Modification 3, since the second electrode 32 can be easily replaced, the man-hours required for maintaining the gas reforming apparatus 100 can be reduced.

[0071] Modification 4. A modification 4 of Embodiment 1 will be described with reference to FIG. 11. FIG. 11 is a cross-sectional view showing a gas reforming apparatus 100 according to a modification 4 of Embodiment 1.

[0072] In the gas reforming apparatus 100 according to Embodiment 1, it is not specified how the gas reforming apparatus 100 is arranged with respect to the gravitational direction. On the other hand, the gas reforming apparatus 100 according to Modification 4 assumes a case where the second reaction chamber 42 is arranged below the first reaction chamber 41 in the gravitational direction.

[0073] As shown in FIG. 11, when the second reaction chamber 42 is arranged below the first reaction chamber 41 in the gravitational direction (-Z direction), even if the reaction accelerator 7 is a granular or powdery substance, it can be stably arranged on the third electrode 33.

[0074] Furthermore, in the gas reforming apparatus 100 of Modification 4, the tip surface of the third electrode 33, which is a lead-out electrode, is recessed when viewed from above in the gravitational direction (+Z direction). That is, in the third electrode 33, the surface on the upper side in the gravitational direction of its tip portion 33a is recessed. By configuring in this way, even if the reaction accelerator 7 is a granular or powdery substance, the reaction accelerator 7 can be stably arranged by the third electrode 33.

[0075] Modification 5. Modification 5 of Embodiment 1 will be described with reference to FIGS. 12 to 14. FIGS. 12 and 14 are cross-sectional views showing a configuration example of the gas reforming apparatus 100 according to Modification 5 of Embodiment 1. Further, FIG. 13 is a cross-sectional view of the E-E portion shown in FIG. 12.

[0076] Regarding Embodiment 1, the flow of the gas to be reformed G1 in the first reaction chamber 41 was described without particular stipulation. In Modification 5, the case where the flow of the gas to be reformed G1 in the first reaction chamber 41 becomes a forward vortex flow and the case where it becomes a reverse vortex flow will be described.

[0077] First, an example of the configuration of the gas reforming apparatus 100 for making the flow of the gas to be reformed G1 in the first reaction chamber 41 a forward vortex flow will be described. In the gas reforming apparatus 100 shown in FIG. 12, two gas inlets 51 are provided at the end portion on the side (+Z direction side) of the side surface of the reaction vessel 2 where the first electrode 31 is arranged.

[0078] Here, as shown in FIG. 13, the reaction vessel 2 has a cylindrical shape with end faces at both ends. Also, the gas inlet 51 is shaped such that the reformed gas G1 flowing in flows along the inner wall surface of the first reaction chamber 41. Specifically, as shown in FIG. 13, when viewed from the axial direction (Z direction) of the symmetry axis of the reaction vessel 2, the opening of the gas inlet 51 is formed so that the direction of the opening faces the tangential direction of the inner wall surface of the reaction vessel 2. However, the structure for flowing the reformed gas G1 flowing in from the gas inlet 51 along the inner wall surface of the first reaction chamber 41 is not limited to this. For example, the reaction vessel 2 may be configured to separately include a member that makes the flow of the reformed gas G1 flowing in from the gas inlet 51 into a flow along the inner wall surface of the first reaction chamber 41.

[0079] The reformed gas G1 flows toward the opening 52 while swirling in the circumferential direction around the symmetry axis (Z1 axis) of the cylindrical reaction vessel 2. In this way, a forward vortex flow is generated inside the first reaction chamber 41.

[0080] Further, in the gas reforming apparatus 100 shown in FIG. 12, the second electrode 32 has an inner wall in a conical shape whose inner diameter becomes narrower as it goes toward the second reaction chamber 42 side (-Z direction side). By configuring it in this way, while maintaining the vortex flow of the reformed gas G1, the flow velocity can be increased and the reformed gas G1 can be made to flow into the second reaction chamber 42.

[0081] Note that it is not essential for the gas inlet 51 to be in two places; it can be in one place. Also, more than two gas inlets 51 may be provided. However, having multiple gas inlets 51 can generate a more stable forward vortex flow than having only one gas inlet 51. When multiple gas inlets 51 are provided, it is preferable to arrange them to be rotationally symmetric with respect to the symmetry axis of the reaction vessel 2 when viewed from the direction of the symmetry axis (Z direction) of the reaction vessel 2. Here, rotational symmetry means a configuration where the arrangement of the gas inlets 51 overlaps when rotated by (360° / n) with respect to the symmetry axis (Z1 axis) of the reaction vessel 2, and n is an integer of 2 or more. By arranging the gas inlets 51 to be rotationally symmetric with respect to the symmetry axis of the reaction vessel 2 when viewed from the direction of the symmetry axis (Z direction) of the reaction vessel 2, a more stable forward vortex flow can be generated.

[0082] Also, in Fig. 13, an example is shown where the gas to be reformed G1 swirls clockwise when viewed in the direction (-Z direction) from the first reaction chamber 41 toward the second reaction chamber 42, but the direction in which the gas to be reformed G1 swirls may be the opposite of this.

[0083] When the flow of the gas to be reformed G1 in the first reaction chamber 41 is a forward vortex flow, the plasma P is stably maintained away from the inner wall of the first reaction chamber 41 (approaching the Z1 axis side), so it is easy to maintain the plasma P at a high temperature.

[0084] Also, when the flow of the gas to be reformed G1 in the first reaction chamber 41 is a forward vortex flow, the gas to be reformed G1 can be retained in the first reaction chamber 41 for a longer time compared to when no vortex flow is generated.

[0085] Next, an example of the configuration of the gas reforming apparatus 100 for causing the flow of the gas to be reformed G1 in the first reaction chamber 41 to be a reverse vortex will be described. In the gas reforming apparatus 100 shown in FIG. 14, two gas inlets 51 are provided at positions on the side surface of the reaction vessel 2 that are in contact with the second electrode 32. The shape of the reaction vessel 2 is a cylindrical shape having end faces at both ends, similar to the example of the forward vortex. Also, similar to the example of the forward vortex, the reaction vessel 2 has a structure in which the gas to be reformed G1 flowing in from the gas inlet 51 flows along the inner wall surface of the first reaction chamber 41.

[0086] The gas to be reformed G1 flows toward the first electrode 31 side (+Z direction side) of the first reaction chamber 41 while swirling in the circumferential direction of the symmetry axis (Z1 axis) of the reaction vessel 2 having a cylindrical shape. Then, after reaching the inner wall on the first electrode 31 side (+Z direction side) of the first reaction chamber 41, it flows toward the opening 52 side (-Z direction side) on the central side (Z1 axis side) of the swirling flow before reaching the inner wall on the first electrode 31 side. In this way, a reverse vortex is generated inside the first reaction chamber 41.

[0087] Even when the flow of the gas to be reformed G1 in the first reaction chamber 41 is a reverse vortex, the plasma P is stably maintained away from the inner wall of the first reaction chamber 41 (approaching the Z1 axis side). Here, the effect of stably maintaining the plasma P is greater when the flow of the gas to be reformed G1 in the first reaction chamber 41 is a reverse vortex than when it is a forward vortex, and the effect of maintaining the plasma P at a high temperature is also greater.

[0088] Also, even when the flow of the gas to be reformed G1 in the first reaction chamber 41 is a reverse vortex, the gas to be reformed G1 can be retained in the first reaction chamber 41 for a longer time compared to the case where no vortex is generated.

[0089] Note that even when the flow of the gas to be reformed G1 in the first reaction chamber 41 is a reverse vortex, the number of gas inlets 51 and the swirling direction of the vortex are not limited. Also, in order to generate the reverse vortex more stably, it is preferable to provide the gas inlets 51 so as to be rotationally symmetric with respect to the symmetry axis of the reaction vessel 2 when viewed from the symmetry axis direction (Z direction) of the reaction vessel 2.

[0090] Further, when the reaction vessel 2 has a structure having a partition portion 21 that partitions the first reaction chamber 41 and the second reaction chamber 42 (see FIG. 9), the gas inlet 51 may be provided at a position on the side surface of the reaction vessel 2 that is in contact with the partition portion 21.

[0091] According to the gas reforming apparatus 100 of Modification 5, since the plasma P is stably maintained away from the inner wall of the first reaction chamber 41 (approaching the Z1 axis side), an effect that the temperature of the plasma P is easily maintained at a high state can be obtained. And according to the gas reforming apparatus 100 of Modification 5, since the plasma P maintained at a high temperature state can reach the third electrode 33, the reaction efficiency between the gas to be reformed G1 and the reaction accelerator 7 can be further increased.

[0092] Further, according to the gas reforming apparatus 100 of Modification 5, since the gas to be reformed G1 stays in the first reaction chamber 41 for a long time due to the vortex, the contact time between the gas to be reformed G1 and the plasma P can be extended, and the reforming efficiency of the gas to be reformed G1 can be improved.

[0093] Modification 6. A modification 6 of Embodiment 1 will be described with reference to FIG. 15. FIG. 15 is a cross-sectional view showing a gas reforming apparatus 100 according to a modification 6 of Embodiment 1.

[0094] Regarding Embodiment 1, it has been described that the material constituting the reaction vessel 2 is preferably a material with high insulation and durability. However, the reaction vessel 2 may be composed of a metal as long as the first electrode 31, the second electrode 32, and the third electrode 33 are each electrically insulated.

[0095] FIG. 15 shows an example in the case where the portion constituting the second reaction chamber 42 in the reaction vessel 2 is composed of a metal. In the gas reforming apparatus 100 shown in FIG. 15, the reaction vessel 2 includes a first main body portion 2a made of an insulating material, an insulating portion 2b made of an insulating material, and a second main body portion 2c made of a metal.

[0096] The configuration of the first main body 2a is the same as that of the gas reforming apparatus 100 in the first embodiment, and thus the description thereof will be omitted. A third electrode 33 is attached to the second main body 2c. The second main body 2c and the third electrode 33 are also electrically connected. Since an insulating portion 2b is interposed between the second main body 2c and the second electrode 32, the second main body 2c and the second electrode 32 are electrically insulated from each other. Also, the third electrode 33 and the second electrode 32 are electrically insulated from each other.

[0097] The type of metal constituting the second main body 2c is not particularly limited. For example, tungsten can be adopted as the metal constituting the second main body 2c for the purpose of improving the heat resistance of the gas reforming apparatus 100. Also, aluminum can be adopted as the metal constituting the second main body 2c for the purpose of reducing the weight of the gas reforming apparatus 100.

[0098] The insulating material constituting the insulating portion 2b is not particularly limited. Examples of the insulating material constituting the insulating portion 2b include glass, ceramics, and resin. Specific examples of the glass constituting the insulating portion 2b include quartz glass or borosilicate glass. Also, specific examples of the ceramics constituting the insulating portion 2b include alumina (Al2O3), zirconia (ZrO2), and magnesia (MgO). Also, specific examples of the resin constituting the insulating portion 2b include PTFE (polytetrafluoroethylene) and PEEK (polyetheretherketone).

[0099] According to the gas reforming apparatus 100 of the sixth modification, since the reaction vessel 2 is configured to contain a metal, an effect can be obtained in that a function according to the characteristics of the metal, such as heat resistance or weight reduction, can be imparted to the reaction vessel 2.

[0100] Embodiment 2. The configuration of the gas reforming apparatus 200 according to Embodiment 2 will be described with reference to FIGS. 16 and 17. As a modification 4 of the gas reforming apparatus 100 according to Embodiment 1, a case where the second reaction chamber 42 is arranged below the first reaction chamber 41 in the gravitational direction was described. The gas reforming apparatus 200 according to Embodiment 2 will describe a configuration example in the case where the first reaction chamber 41 is arranged below the second reaction chamber 42 in the gravitational direction. Therefore, descriptions of points common to the gas reforming apparatus 100 according to Embodiment 1 will be omitted or simplified. In addition, the same reference numerals are given to the configurations common to the gas reforming apparatus 100 according to Embodiment 1.

[0101] Similar to the gas reforming apparatus 100 of Embodiment 1, the gas reforming apparatus 200 of the present embodiment includes a reaction vessel 2, a first electrode 31, a second electrode 32, a third electrode 33 as a lead-out electrode, and a reaction accelerator 7. Further, the reaction vessel 2 includes a first reaction chamber 41 and a second reaction chamber 42.

[0102] FIG. 16 is a cross-sectional view showing the gas reforming apparatus 200 according to Embodiment 2. FIG. 17 is a cross-sectional view of the F-F portion shown in FIG. 16. In FIGS. 16 and 17, the direction from the first reaction chamber 41 to the second reaction chamber 42 (+Z direction) corresponds to the upward direction in the gravitational direction.

[0103] Also in the gas reforming apparatus 200 according to Embodiment 2, since the reaction accelerator 7 is arranged inside the second reaction chamber 42 that is thermally partitioned from the first reaction chamber 41, the reaction accelerator 7 can be maintained in a high-temperature state. Therefore, according to the gas reforming apparatus 200 according to Embodiment 2, the gas to be reformed G1 can be efficiently reformed.

[0104] As shown in FIG. 16, in the gas reforming apparatus 200 according to Embodiment 2, the second reaction chamber 42 is located above the first reaction chamber 41 in the gravitational direction (+Z direction). And the third electrode 33 which is a lead-out electrode is arrange | positioned in the 2nd reaction chamber 42. As shown in FIGS. 16 and 17, an inlet 9 for supplying the reaction accelerator 7 to the third electrode 33 is provided on the upper surface of the reaction vessel 2 in the gravitational direction, separately from the gas outlet 53.

[0105] As shown in FIGS. 16 and 17, a through hole 331 through which the gas to be reformed G1 passes is provided at the tip 33a of the third electrode 33. Note that the shape of the third electrode 33 in the present embodiment is merely an example. For example, the cross-sectional shape of the tip 33a in a plane (XY plane) perpendicular to the direction in which the first electrode 31 and the second electrode 32 face each other may be rectangular. Also, the cross-sectional shape of the through hole 331 in the XY plane does not have to be circular. For example, the cross-sectional shape of the through hole 331 in the XY plane may be rectangular.

[0106] When the reaction accelerator 7 is a substance that is consumed in the process of reforming the gas to be reformed G1, it is necessary to supply the reaction accelerator 7 to the third electrode 33 in order to maintain the reforming efficiency of the gas to be reformed G1 by the gas reforming apparatus 200. For a specific example, when the reaction accelerator 7 is carbon and CO is generated from CO2 contained in the gas to be reformed G1, the carbon is consumed as shown in the following formula (4) which is reproduced below. C + CO2 ←→ 2CO ··· (4)

[0107] In the gas reforming apparatus 200 according to Embodiment 2, when the reaction accelerator 7 is introduced from an introduction port 9 provided above the third electrode 33 in the gravitational direction (+Z direction), the reaction accelerator 7 is supplied to the third electrode 33 according to gravity. Therefore, according to the gas reforming apparatus 200 according to Embodiment 2, the reaction accelerator 7 can be easily supplied to the third electrode 33 without stopping the operation of the gas reforming apparatus 200.

[0108] The configuration of the gas reforming apparatus 200 described above with reference to FIGS. 16 and 17 is merely an example, and the gas reforming apparatus 200 of the present embodiment can adopt various variations. Hereinafter, the structure in the modification will be described with reference to the drawings.

[0109] Modification. A modification of Embodiment 2 will be described with reference to FIGS. 18 and 19. FIG. 18 is a cross-sectional view showing a gas reforming apparatus 200 according to a modification of Embodiment 2. FIG. 19 is a cross-sectional view of the G-G portion shown in FIG. 18. Note that, in order to explain the effects of the modification of Embodiment 2, FIG. 16 is also referred to.

[0110] As shown in FIGS. 18 and 19, in the gas reforming apparatus 200 according to the modification, an insulating member 8 is disposed between the second electrode 32 and the third electrode 33. The insulating member 8 is attached to the reaction vessel 2. Note that when the insulating member 8 is made of the same insulating material as the reaction vessel 2, the insulating member 8 may be integrally formed with the reaction vessel 2. Further, it is not essential that the insulating member 8 is attached to the reaction vessel 2, and it may be attached to the second electrode 32 or the third electrode 33.

[0111] As shown in FIGS. 18 and 19, the shape of the insulating member 8 is a ring shape. However, the shape of the insulating member 8 is an example and is not limited to the ring shape. For example, when the shape of the opening of the opening 52 is rectangular, the shape of the insulating member 8 may be a shape having a rectangular opening.

[0112] The insulating material constituting the insulating member 8 is not particularly limited. Examples of the insulating material constituting the insulating member 8 include glass, ceramics, and resin. Specific examples of the glass constituting the insulating member 8 include quartz glass and borosilicate glass. Further, specific examples of the ceramics constituting the insulating member 8 include alumina (Al2O3), zirconia (ZrO2), and magnesia (MgO). Specific examples of the resin constituting the insulating member 8 include PTFE and PEEK.

[0113] The effects of the gas reforming apparatus 200 according to the modification of Embodiment 2 will be described in comparison with the gas reforming apparatus 200 according to Embodiment 2. In the gas reforming apparatus 200 according to Embodiment 2, the third electrode 33 was arranged so as to be separated from the second electrode 32 so as not to contact it (see FIG. 16). Therefore, as a path for the reformable gas G1 flowing in from the opening 52 to the gas outlet 53, there were a path passing through the through hole 331 and a path passing between the second electrode 32 and the third electrode 33.

[0114] Here, in order to improve the reforming efficiency of the reformable gas G1, it is desirable to bring the reformable gas G1 into contact with the reaction accelerator 7 as much as possible. And it is possible to bring the reformable gas G1 into contact with the reaction accelerator 7 more efficiently when the reformable gas G1 passes through the through hole 331 rather than between the second electrode 32 and the third electrode 33.

[0115] And in the gas reforming apparatus 200 according to the modification, the insulating member 8 is arranged between the second electrode 32 and the third electrode 33 so as to suppress the reformable gas G1 from passing between the second electrode 32 and the third electrode 33 and allow more reformable gas G1 to pass through the through hole 331.

[0116] In the gas reforming apparatus 200 according to the modification, more reformable gas G1 can be made to flow into the through hole 331 than when the insulating member 8 is not arranged. Therefore, according to the gas reforming apparatus 200 according to the modification, the reformable gas G1 and the reaction accelerator 7 can be efficiently brought into contact with each other, and the reforming efficiency of the reformable gas G1 can be improved.

[0117] Note that the insulating member 8 may be arranged so as to suppress the reformable gas G1 from passing between the second electrode 32 and the third electrode 33 and allow more reformable gas G1 to flow into the through hole 331. For example, there may be a gap between the insulating member 8 and the second electrode 32 or between the insulating member 8 and the third electrode 33. That is, it is not essential to make all of the reformable gas G1 flowing in from the opening 52 flow into the through hole 331.

[0118] The above has described Embodiment 1 and Embodiment 2 of the present disclosure. The present disclosure is not limited to the above-described examples, and design changes can be appropriately made within the scope that satisfies the configuration of the present disclosure. For example, when at least one configuration in the present disclosure is deformed, added, or omitted, or when at least one component is extracted and combined with the components of other embodiments, it is possible.

[0119] The gas reforming device according to the present disclosure can reform highly harmful substances contained in the gas to be reformed into substances with low harmfulness. Therefore, the gas reforming device according to the present disclosure contributes to Goal 3 of the Sustainable Development Goals (SDGs) led by the United Nations, "Ensure healthy lives and promote well-being for all people of all ages."

[0120] In addition, the gas reforming device according to the present disclosure can reform the gas to be reformed into a substance that can be used as fuel. Therefore, the gas reforming device according to the present disclosure contributes to Goal 7 of the Sustainable Development Goals (SDGs) led by the United Nations, "Enable access for all people to affordable, reliable, and sustainable modern energy."

[0121] In addition, the gas reforming device according to the present disclosure can reform the gas to be reformed with a high global warming potential into a substance with a low global warming potential. Therefore, the gas reforming device according to the present disclosure contributes to Goal 13 of the Sustainable Development Goals (SDGs) led by the United Nations, "Take urgent action to combat climate change and its impacts."

Explanation of Reference Numerals

[0122] 100, 200 Gas reforming device 2 Reaction vessel 21 Partition part 2a First main body part 2b Insulating part 2c Second main body part 31 First electrode 32 Second electrode 33 Third electrode (lead-out electrode) 33a Tip part 33b Shaft part 331 Through-hole 41 First reaction chamber 42 Second reaction chamber 51 Gas inlet 52 Opening 53 Gas outlet 61 First power source 62 Second power source 63 Passive element 7 Reaction accelerator 8 Insulating member 9 Inlet G1 Gas to be reformed G2 Reformed gas P Plasma

Claims

1. A gas reforming apparatus for generating plasma to reform a gas to be reformed, comprising: a reaction vessel including a first reaction chamber into which the gas to be reformed flows and a second reaction chamber into which the gas to be reformed that has flowed through the first reaction chamber flows, the second reaction chamber being thermally partitioned from the first reaction chamber; a first electrode provided in the first reaction chamber; a second electrode that is installed so as to partition the first reaction chamber and the second reaction chamber or that is installed in a partition portion that partitions the first reaction chamber and the second reaction chamber, and that generates plasma with the first electrode; a draw-out electrode provided in the second reaction chamber that draws the plasma from the first reaction chamber into the second reaction chamber due to a potential difference with the second electrode; and a reaction accelerator that promotes the reforming reaction of the gas to be reformed by the plasma. The reaction accelerator is disposed on the draw-out electrode. A gas reforming apparatus.

2. When the second electrode is installed so as to partition the first reaction chamber and the second reaction chamber, an opening that connects the first reaction chamber and the second reaction chamber is formed in the second electrode, and when the second electrode is installed in the partition portion, the opening is formed in the partition portion. The gas reforming apparatus according to claim 1.

3. The draw-out electrode is provided at a position facing the opening. The gas reforming apparatus according to claim 2.

4. The reaction accelerator is disposed in a portion of the draw-out electrode that faces the opening. The gas reforming apparatus according to claim 2.

5. The reaction vessel has an axially symmetric shape. The gas reforming apparatus according to claim 2.

6. The opening is formed on the axis of symmetry of the reaction vessel. The gas reforming apparatus according to claim 5.

7. The gas inlet for introducing the gas to be reformed into the first reaction chamber is provided at an end of a side surface of the reaction vessel on the side where the first electrode is disposed. The reaction vessel according to claim 5, wherein the reaction vessel has a structure in which the gas to be reformed flowing in from the gas inlet flows along the inner wall surface of the first reaction chamber. **Claim 8** The gas reforming apparatus according to claim 7, wherein a plurality of the gas inlets are provided so as to be rotationally symmetric with respect to the axis of symmetry of the reaction vessel when viewed in the axial direction of the reaction vessel. **Claim 9** The reaction vessel has an axisymmetric shape. On the side surface of the reaction vessel, a gas inlet for introducing the gas to be reformed into the first reaction chamber is provided so as to be in contact with the second electrode or the partition portion. The reaction vessel according to claim 2, wherein the reaction vessel has a structure in which the gas to be reformed flowing in from the gas inlet flows along the inner wall surface of the first reaction chamber. **Claim 10** The gas reforming apparatus according to claim 9, wherein a plurality of the gas inlets are provided so as to be rotationally symmetric with respect to the axis of symmetry of the reaction vessel when viewed in the axial direction of the reaction vessel. **Claim 11** The first reaction chamber is provided above the second reaction chamber in the direction of gravity. The gas reforming apparatus according to any one of claims 1 to 10, wherein the tip surface of the extraction electrode is recessed when viewed from above in the direction of gravity. **Claim 12** The second reaction chamber is provided above the first reaction chamber in the direction of gravity. The gas reforming apparatus according to any one of claims 1 to 10, wherein the extraction electrode has a through hole for allowing the gas to be reformed flowing into the second reaction chamber to pass through. **Claim 13** The second reaction chamber is provided above the first reaction chamber in the direction of gravity. The extraction electrode has a through hole for allowing the gas to be reformed flowing into the second reaction chamber to pass through. The gas reforming apparatus according to any one of claims 2 to 4, wherein the lead-out electrode is arranged such that the through hole faces the opening.

14. The gas reforming apparatus according to claim 12, wherein an insulating member that suppresses the reforming gas from passing between the second electrode and the lead-out electrode is arranged between the second electrode and the lead-out electrode.

15. The reaction vessel is configured to contain a metal, The gas reforming apparatus according to any one of claims 1 to 10, wherein the first electrode and the second electrode, the first electrode and the lead-out electrode, and the second electrode and the lead-out electrode are electrically insulated from each other.

16. The gas reforming apparatus according to any one of claims 1 to 10, wherein the shape of the tip of the first electrode is a ring shape.

17. The gas reforming apparatus according to any one of claims 1 to 10, wherein the reaction promoter is a catalyst.

18. The gas reforming apparatus according to any one of claims 1 to 10, wherein the reforming gas contains carbon dioxide and the reaction promoter contains carbon.

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