Gas reforming device

Abstract

This gas reforming device (100) is provided with: a reaction container (2) provided with a first reaction chamber (41) into which a gas (G1) to be reformed flows, and a second reaction chamber (42) into which the gas (G1) to be reformed that has flowed through the first reaction chamber (41) flows and which is thermally partitioned from the first reaction chamber (41); first and second electrodes (31, 32) that are provided in the first reaction chamber (41) and generate plasma (P) in the first reaction chamber (41); a lead-out electrode (33) that is provided in the second reaction chamber (42) and draws out 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

Gas Reformer

[0001] The present disclosure relates to a gas reformer.

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

[0003] International Publication No. 2022 / 234039

[0004] In a gas reforming apparatus that generates plasma to reform a gas to be reformed, it has been desired to obtain a larger amount of reformed gas relative to the amount of energy input to the gas reforming apparatus.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a gas reforming device that can efficiently reform a gas to be reformed.

[0006] The gas reforming device according to the present disclosure comprises a reaction vessel having a first reaction chamber into which a gas to be reformed flows, and a second reaction chamber, thermally separated from the first reaction chamber, into which the gas to be reformed that has passed through the first reaction chamber flows; first and second electrodes provided within the first reaction chamber for generating plasma within the first reaction chamber; an extraction electrode provided within the second reaction chamber for extracting the plasma from the first reaction chamber into the second reaction chamber; and a reaction accelerator disposed on the extraction electrode.

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

[0008] 1. A cross-sectional view showing a gas reformer according to a first embodiment. 2. A cross-sectional view taken along line A-A in FIG. 1. 3. A cross-sectional view taken along line B-B in FIG. 1. 4. A schematic diagram showing another example of the configuration of a power supply circuit in the gas reformer according to the first embodiment. 5. A schematic diagram showing an example of a gas flow in the gas reformer according to the first embodiment. 6. A cross-sectional view showing a gas reformer according to a first modified example of the first embodiment. 7. A cross-sectional view showing a gas reformer according to a second modified example of the first embodiment. 8. A cross-sectional view taken along line C-C in FIG. 7. 9. A cross-sectional view showing a gas reformer according to a third modified example of the first embodiment. 10. A cross-sectional view taken along line D-D in FIG. 19. 11. A cross-sectional view showing a gas reformer according to a fourth modified example of the first embodiment. 12. A cross-sectional view showing a gas reformer according to a fifth modified example of the first embodiment. 13. A cross-sectional view taken along line E-E in FIG. 12. 14. A cross-sectional view showing another configuration of a gas reformer according to a fifth modified example of the first embodiment. 15. A cross-sectional view showing a gas reformer according to a sixth modified example of the first embodiment. 16. A cross-sectional view showing a gas reformer according to a second embodiment. 17. A cross-sectional view taken along line F-F in FIG. 16. 18. A cross-sectional view showing a gas reformer according to a second modified example of the second embodiment.

[0009] A gas reforming apparatus according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the drawings are schematic illustrations, and the dimensional ratios and the number of components in the drawings do not necessarily correspond to the actual dimensional ratios and the number of components.

[0010] First Embodiment The configuration of a gas reforming apparatus 100 according to a first embodiment will be described with reference to Figures 1 to 4. Figures 1 to 4 are diagrams that schematically show the configuration of the gas reforming apparatus 100 according to the first embodiment. Figure 2 is a cross-sectional view of the A-A portion shown in Figure 1. Figure 3 is a cross-sectional view of the B-B portion shown in Figure 1. Figure 4 is a diagram that schematically shows another example of the configuration of the power supply circuit in the gas reforming apparatus 100 shown in Figure 1.

[0011] As shown in Figure 1, the gas reforming device 100 comprises a reaction vessel 2 having a first reaction chamber 41 into which the reformed gas G1 flows and a second reaction chamber 42 into which the reformed gas G1 that has passed through the first reaction chamber 41 flows, a first electrode 31 and a second electrode 32 that are provided in the first reaction chamber 41 and generate plasma P in the first reaction chamber 41, a third electrode 33 that is provided in the second reaction chamber 42 and is an extraction electrode that draws plasma P from the first reaction chamber 41 into the second reaction chamber 42, and a reaction accelerator 7 that is arranged on the third electrode 33 that is an extraction 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 perpendicular to the Z axis is defined as the XY plane. The following description will be made with reference to the XYZ coordinate system defined in this manner as appropriate. Note that, in this specification, when expressing a direction, a positive or negative sign is added, such as "+Z direction" or "-Z direction." When expressing a direction without distinguishing between positive and negative, the direction is simply referred to as the "Z direction." In other words, in this specification, when simply referring to the "Z direction," both the "+Z direction" and the "-Z direction" are included. In this embodiment, the direction from the first reaction chamber 41 toward the second reaction chamber 42 is the -Z direction.

[0013] The shape of the reaction vessel 2 is symmetrical about the Z1 axis shown in FIG. 1 . In this 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 on 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 that the reaction vessel 2 have an axially symmetrical shape or symmetrical structure.

[0014] The material constituting the reaction vessel 2 is not particularly limited, but is preferably a material with high insulating properties and durability. Specifically, the reaction vessel 2 is preferably made of glass or ceramics. Specific examples of glass constituting the reaction vessel 2 include quartz glass and borosilicate glass. Specific examples of ceramics constituting the reaction vessel 2 include alumina (Al ２ O ３ ), zirconia (ZrO ２ ), and magnesia (MgO).

[0015] 1, the reaction vessel 2 is provided with a gas inlet 51 for allowing the reformed gas G1 to flow into the first reaction chamber 41. The position where the gas inlet 51 is provided is not particularly limited as long as it allows the reformed gas G1 to flow into the first reaction chamber 41. The gas inlet 51 may be provided at multiple locations. In this embodiment, the gas inlet 51 is provided at one location on the end surface of the reaction vessel 2 on the +Z direction side.

[0016] 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 location of the gas outlet 53 is not particularly limited as long as it allows the reformed gas G2 to flow out from the second reaction chamber 42. The gas outlet 53 may be provided at multiple locations. In this embodiment, one gas outlet 53 is provided on the end face of the reaction vessel 2 on the -Z direction side.

[0017] 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 (the +Z direction). In addition, the first electrode 31 is exposed to the inside of the first reaction chamber 41, and therefore can also be said to be provided inside the first reaction chamber 41.

[0018] 1 and 2, the first electrode 31 has a cylindrical shape. 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 materials that can be used to make the first electrode 31 include stainless steel, titanium, molybdenum, and tungsten. However, the material that can be used to make the first electrode 31 is not limited to these, and any conductive material that has high corrosion resistance and heat resistance can be used.

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

[0021] 1 and 2 , the second electrode 32 has a disk shape. 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. The second electrode 32 also serves as a member that thermally separates the first reaction chamber 41 and the second reaction chamber 42. Here, in this specification, "thermally separating" refers to suppressing heat transfer due to thermal conduction, convection, or radiation by a certain member or structure, and also includes insulation.

[0022] The second electrode 32 is made of a conductive material, similar to the first electrode 31. Specific examples of materials constituting the second electrode 32 are similar to those of the first electrode 31, and therefore will not be described here. 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 made of a material containing tungsten, and the second electrode 32 may be made of a material containing molybdenum.

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

[0024] As shown in FIGS. 1 and 3 , the third electrode 33 has a shape including a tip portion 33 a and a shaft portion 33 b. In this embodiment, the tip portion 33 a has a disk shape. The shaft portion 33 b has a cylindrical shape. However, the shape of the third electrode 33 in this embodiment is merely an example. For example, the tip portion 33 a may have a tapered shape in which the diameter decreases toward the tip. Furthermore, it is not essential that the third electrode 33 has a shape including the tip portion 33 a, and the third electrode 33 may have a cylindrical shape including only the shaft portion 33 b.

[0025] The third electrode 33 is made of a conductive material, similar to the first electrode 31. Specific examples of materials constituting the third electrode 33 are similar to those of the first electrode 31, and therefore will not be described here. 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 , a reaction accelerator 7 is disposed on the surface of the tip portion 33a of the third electrode 33 facing the opening 52. The reaction accelerator 7 is a substance that accelerates the reforming reaction of the reformed gas G1 by the plasma P. The reaction accelerator 7 may be disposed over the entire surface of the tip portion 33a facing the opening 52, or may be disposed on only a part of that surface. Details of the reforming reaction of the reformed gas G1 by the plasma P will be described later. An appropriate substance is selected as the reaction accelerator 7 depending on the type of the reformed gas G1. The reaction accelerator 7 is, for example, a catalyst, a reducing agent, or an oxidizing agent.

[0027] The reaction accelerator 7 is typically placed on the third electrode 33 by placing or adhering the reaction accelerator 7 on the surface of the third electrode 33. However, the manner in which the reaction accelerator 7 is placed on the third electrode 33 is not limited to these. For example, the reaction accelerator 7 may be placed on the third electrode 33 by modifying the surface of the third electrode 33 into a substance containing the reaction accelerator 7. Specifically, for example, when the third electrode 33 is made of 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 into tungsten carbide. The carbonization may be 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] 1 , the first electrode 31 and the second electrode 32 are connected via a first power supply 61. The first power supply 61 is a DC power supply 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, a plasma P can be generated inside the first reaction chamber 41.

[0029] The voltage value output by the first power supply 61 is designed appropriately in accordance with various conditions so as to stably generate the plasma P. Conditions taken into consideration for designing the voltage value output by the first power supply 61 include, for example, the distance between the first electrode 31 and the second electrode 32, the composition of the reforming target gas G1, the flow rate of the reforming target gas G1, and the pressure inside the first reaction chamber 41.

[0030] The first power supply 61 is not limited to a DC power supply. As long as the first power supply 61 can generate plasma P inside the first reaction chamber 41, it may be an AC power supply or a pulse power supply. When the first power supply 61 is an AC power supply, the peak value and frequency are appropriately designed depending on various conditions, as in the case where the first power supply 61 is a DC power supply. When the first power supply 61 is a pulse power supply, the peak value and duty ratio are appropriately designed depending on various conditions, as in the case where the first power supply 61 is a DC power supply.

[0031] 1 , the second electrode 32 and the third electrode 33 are connected via a second power supply 62. The third electrode 33 is grounded. The second power supply 62 is a DC power supply 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 extracted into the second reaction chamber 42. Therefore, the third electrode 33 can also be said to be an extraction electrode that extracts 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 supply 62 is designed appropriately in accordance with various conditions so that the plasma P generated inside the first reaction chamber 41 can be drawn into the second reaction chamber 42. Conditions that are taken into consideration for designing the voltage value output by the second power supply 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 to-be-reformed gas G1, the flow rate of the to-be-reformed gas G1, and the pressure inside the second reaction chamber 42. For the second power supply 62 as well, an AC power supply or a pulse power supply can be adopted instead of a DC power supply.

[0033] Furthermore, it is not essential that the gas reforming apparatus 100 include the second power supply 62. As shown in Fig. 4, the gas reforming apparatus 100 may be configured to include a passive element 63 instead of the second power supply 62. The passive element 63 is, for example, a resistor or a capacitor.

[0034] 4, the action of the first power supply 61 and the passive element 63 generates a potential difference with respect to the ground potential between the second electrode 32 and the third electrode 33. This potential difference causes the plasma P to be drawn into the second reaction chamber 42.

[0035] By using a passive element 63 instead of the second power supply 62, it is possible to simplify the configuration of the power supply circuit of the gas reforming apparatus 100. By simplifying the configuration of the power supply circuit of the gas reforming apparatus 100, it is possible to achieve the effect of facilitating maintenance of the gas reforming apparatus 100.

[0036] If 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 reforming apparatus 100 does not need to include the passive element 63. By omitting the passive element 63, the configuration of the power supply circuit of the gas reforming apparatus 100 can be further simplified.

[0037] Next, the operation of the gas reforming apparatus 100 according to the first embodiment will be described with reference to Fig. 1 and Fig. 5. Fig. 5 is a schematic diagram showing an example of the flow of the reformed gas G1 in the gas reforming apparatus 100 according to the first embodiment.

[0038] First, we will explain the flow of the reformed gas G1 in the gas reforming device 100. As shown in Fig. 5, the reformed gas G1 is caused to flow into the first reaction chamber 41 from the gas inlet 51. The reformed gas G1 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 that has been 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, the plasma P is generated inside the first reaction chamber 41. The plasma P reforms the reformed gas G1 flowing inside the first reaction chamber 41. The mechanism by which the plasma P reforms the reformed gas G1 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 second reaction chamber 42. The plasma P reforms the reforming target gas G1 flowing through the second reaction chamber 42.

[0041] Furthermore, the reforming reaction of the to-be-reformed gas G1 by the plasma P is promoted by the action of the reaction accelerator 7 arranged on the third electrode 33. Here, since the reaction accelerator 7 is arranged on the third electrode 33, it receives heat from the third electrode 33, which is heated by receiving heat from the plasma P, and is thereby heated. Furthermore, since the reaction accelerator 7 is arranged in the second reaction chamber 42, which is thermally separated from the first reaction chamber 41, it is difficult for heat to be dissipated and its temperature to decrease. The higher the temperature of the reaction accelerator 7, the more efficient the reaction with the to-be-reformed gas G1 becomes. Therefore, according to the gas reforming device 100 of this embodiment, the reforming efficiency of the to-be-reformed gas G1 (the amount of reformed gas G2 produced relative to the amount of energy input) is improved.

[0042] Furthermore, the reaction accelerator 7 is disposed on the side of the third electrode 33 facing the opening 52 (the +Z side), and therefore 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 to-be-reformed gas G1. In this way, by disposing the reaction accelerator 7 so that the plasma P comes into contact with the reaction accelerator 7, the to-be-reformed gas G1 can be reformed more efficiently.

[0043] Furthermore, in the gas reforming apparatus 100 according to this embodiment, the reaction accelerator 7 is disposed so that the plasma P comes into contact with the reaction accelerator 7, thereby suppressing energy loss of molecules excited by the plasma P until they reach the reaction accelerator 7. Furthermore, the molecules excited by the plasma P can be made to reach the reaction accelerator 7 before they disappear due to recombination or diffusion. This action also improves the reforming efficiency of the reformed gas G1 by the plasma P.

[0044] Next, the mechanism of gas reforming by the gas reforming apparatus 100 according to the first embodiment will be described. Here, the reformed gas G1 is carbon dioxide (CO ２ ), the reaction accelerator 7 is carbon (C), and carbon monoxide (CO) is generated as the reformed gas G2. The carbon functions as a reducing agent. In this example, the gas reforming device 100 converts the reformed gas G1 (CO ２) into a substance (CO) that can be used as a fuel. The reformed gas G1, the reaction accelerator 7, and the reformed gas G2 are not limited to these.

[0045] The high voltage applied between the first electrode 31 and the second electrode 32 accelerates the electrons present in the space within the first reaction chamber 41. ２ When a molecule of CO collides with a high-energy electron, CO is produced by the decomposition reaction of equation (1): e + CO ２ →CO+O ‥‥(1)

[0046] In formula (1), e represents an electron and O represents atomic oxygen. The decomposition reaction of formula (1) can involve direct dissociation by electrons or CO ２ However, equation (1) expresses these multiple reaction paths collectively.

[0047] Some of the O generated by the reaction of formula (1) combines with other O to form oxygen (O ２ In addition, some of the O generated by the reaction of formula (1) is recombined with CO to form CO ２ In addition, a part of the CO generated by the reaction of formula (1) is converted into O ２ is oxidized by CO ２ Here, since CO is to be produced as the reformed gas G2, the CO generated by the reaction of formula (1) is converted into CO ２ This means that the efficiency of gas reforming is reduced. Therefore, the O generated by the reaction of formula (1) and the O generated by bonding between O ２ should be removed promptly.

[0048] In the gas reforming apparatus 100 according to the first embodiment, carbon (C) as the reaction accelerator 7 is placed on the third electrode 33, and the plasma P comes into contact with the carbon (C) as the reaction accelerator 7. At this time, the O generated by the reaction of formula (1) is removed by the oxidation reaction of formula (2). In addition, the O generated by the reaction of formula (1) is bonded to each other by the oxidation reaction of formula (3). ２ is removed. C + O → CO (2) C + O ２ →CO ２ ...(3)

[0049] Also, C (carbon) and CO ２ Between C and CO, the Boudouard equilibrium relationship of equation (4) is established. ２ ←→2CO ‥‥(4)

[0050] Here, the generation of CO according to the formulas (2) and (4) increases as the temperature increases. ２ The efficiency of reforming the CO gas from the CO to the reformed gas G2 improves as the temperature increases.

[0051] In the gas reforming apparatus 100 according to the first embodiment, the plasma P is drawn into the second reaction chamber 42 by the third electrode 33, which is the drawing electrode, and the plasma P is brought into contact with the carbon (C), which is the reaction accelerator 7. Therefore, the plasma P generates CO ２ Regarding the O generated from the reaction (see formula (1)), it is possible to remove the O by reacting the O with carbon (C) as the reaction accelerator 7 (see formula (2)) before the O recombines with CO. In other words, the gas reforming apparatus 100 according to the first embodiment prevents a decrease in the reforming efficiency of the reformed gas G1.

[0052] Furthermore, in the gas reforming apparatus 100 according to the first embodiment, the carbon (C) serving as the reaction accelerator 7 is disposed in the second reaction chamber 42, which is thermally separated from the first reaction chamber 41. This allows the carbon (C) serving as the reaction accelerator 7 to be maintained at a high temperature. ２The chemical reaction (equation (3)) for removing O and O, which cause a decrease in the efficiency of gas reforming, is activated as the temperature increases. Therefore, by maintaining the carbon (C) as the reaction accelerator 7 at a high temperature, the reaction is accelerated. ２ Furthermore, by maintaining the carbon (C) as the reaction accelerator 7 at a high temperature, the generation of CO according to formula (4) can be further promoted. Therefore, according to the gas reforming apparatus 100 of the first embodiment, CO ２ can be efficiently reformed into CO.

[0053] The reformed gas G1 is CO ２ The description of gas reforming illustrating the above case is an example of reforming the to-be-reformed gas G1 into a substance that can be used as a fuel by the gas reforming device 100. The gas reforming device 100 can also be used for other purposes. For example, the gas reforming device 100 can also be used for reforming highly harmful substances contained in the to-be-reformed gas G1 into less harmful substances. Specifically, for example, a case can be cited in which volatile organic compounds (VOCs) such as toluene or xylene are decomposed using a catalyst such as platinum (Pt) or palladium (Pd).

[0054] The gas reforming device 100 can also be used to reform a gas to be reformed, which has a high global warming potential, into a substance with a low global warming potential. ２ For example, hydrogen peroxide (H2O) is decomposed into nitrogen (N2) and oxygen (O2) using a catalyst such as platinum (Pt) or palladium (Pd).

[0055] The configuration of the gas reforming apparatus 100 described above is merely an example, and various variations of the gas reforming apparatus 100 of this embodiment can be adopted. The structure of the modified example will be described below with reference to the drawings. Note that explanations of points common to the gas reforming apparatus 100 of the first embodiment will be omitted or simplified. Furthermore, the same reference numerals are used to designate components common to the gas reforming apparatus 100 of the first embodiment.

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

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

[0058] As shown in Fig. 6, in the gas reforming device 100 of Modification 1, the first electrode 31 is disposed at a position offset from the Z1 axis on which the third electrode 33 is disposed. In 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 when the shape is not curved. Furthermore, when the length of the plasma P in the first reaction chamber 41 is extended, more of the reformed gas G1 comes into contact with the plasma P, and therefore the proportion of the reformed gas G1 that is reformed by the plasma P is increased.

[0059] Modification 2. Modification 2 of embodiment 1 will be described with reference to Figures 7 and 8. Figure 7 is a cross-sectional view showing a gas reforming apparatus 100 according to modification 2 of embodiment 1. Figure 8 is a cross-sectional view taken along the line CC shown in Figure 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 of the to-be-reformed gas G1 inside the first reaction chamber 41. In addition, the path of the plasma P generated between the first electrode 31 and the third electrode 33 changes depending on the electric field inside the first reaction chamber 41 and the second reaction chamber 42 and the flow of the to-be-reformed gas G1 inside the first reaction chamber 41 and the second reaction chamber 42. In addition, when the path of the plasma P changes, the point of contact with the plasma P may move at each electrode.

[0061] 7 and 8, in the gas reforming apparatus 100 of Modification 2, the tip end shape of the first electrode 31 is ring-shaped. In this case, compared to when the first electrode 31 is cylindrical (see FIGS. 1 and 2), the tip end surface of the first electrode 31 is largely expanded 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, the first electrode 31 having a ring-shaped tip has a large range of movement of the contact point with the plasma P. When the contact point between the first electrode 31 and the plasma P moves significantly, it is possible to prevent the first electrode 31 from being locally heated. Preventing the first electrode 31 from being locally heated can suppress wear and deformation of the first electrode 31, thereby extending the life of the first electrode 31.

[0063] In this way, in the gas reforming apparatus 100 of Modification 2, the first electrode 31 can be made to have a long life, allowing the gas reforming apparatus 100 to operate stably for a long period of time. Furthermore, by making the first electrode 31 have a long life, the frequency of replacement of the first electrode 31 can be reduced, thereby reducing the number of maintenance steps required for the gas reforming apparatus 100. The shape of the first electrode 31 in Modification 2 is an example of a modification for making the first electrode 31 have a long life. The shape of the first electrode 31 is designed as appropriate for the purpose of increasing the life or for other purposes.

[0064] Modification 3. Modification 3 of embodiment 1 will be described with reference to Figures 9 and 10. Figure 9 is a cross-sectional view showing a gas reforming apparatus 100 according to modification 3 of embodiment 1. Figure 10 is a cross-sectional view taken along the line DD shown in Figure 9.

[0065] In the first embodiment, the opening 52, which is an opening that connects the first reaction chamber 41 and the second reaction chamber 42, is provided in the second electrode 32. 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 including a partition 21 that separates the first reaction chamber 41 and the second reaction chamber 42. The partition 21 is provided with an opening 52 that connects the first reaction chamber 41 and the second reaction chamber 42. A second electrode 32 is disposed on the surface of the partition 21 that faces the first electrode 31 (the surface on the +Z direction side). As shown in Fig. 10, the second electrode 32 is composed of four rectangular flat plates.

[0067] The material constituting the partition section 21 is not particularly limited. Since the second electrode 32 is attached to the partition section 21, the material constituting the partition section 21 is preferably a material that is easy to process. In addition, the material constituting the partition section 21 is preferably a material that has good durability against the plasma P. The partition section 21 is made of, for example, alumina (Al ２ O ３ ), zirconia (ZrO ２ ), magnesia (MgO), or other ceramics.

[0068] In the gas reforming apparatus 100 of the third modification, the partition 21 functions as a member that thermally separates the first reaction chamber 41 and the second reaction chamber 42 .

[0069] Alternatively, the second electrode 32 may be ring-shaped, and both the second electrode 32 and the partition 21 may be provided with an opening 52 that is an opening that connects the first reaction chamber 41 and the second reaction chamber 42. In this case, both the partition 21 and the second electrode 32 function as members that thermally separate the first reaction chamber 41 and the second reaction chamber 42.

[0070] Furthermore, in the gas reforming apparatus 100 of Modification 3, the second electrode 32 is provided in the partition section 21, so that the second electrode 32 can be easily replaced if worn or deformed. According to the gas reforming apparatus 100 of Modification 3, the second electrode 32 can be easily replaced, so that the number of steps required for maintenance of the gas reforming apparatus 100 can be reduced.

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

[0072] In the gas reforming apparatus 100 according to the first embodiment, the arrangement of the gas reforming apparatus 100 relative to the direction of gravity is not specified. On the other hand, in the gas reforming apparatus 100 according to the fourth modification, it is assumed that the second reaction chamber 42 is arranged below the first reaction chamber 41 in the direction of gravity.

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

[0074] Furthermore, in the gas reforming apparatus 100 of the fourth modification, the tip surface of the third electrode 33, which is an extraction electrode, is recessed when viewed from above in the direction of gravity (+Z direction). That is, the surface of the tip portion 33a of the third electrode 33 that faces upward in the direction of gravity is recessed. With this configuration, even if the reaction accelerator 7 is a granular or powdery substance, the reaction accelerator 7 can be more stably arranged on the third electrode 33.

[0075] Modification 5. Modification 5 of embodiment 1 will be described with reference to Figures 12 to 14. Figures 12 and 14 are cross-sectional views showing examples of the configuration of a gas reforming apparatus 100 according to modification 5 of embodiment 1. Figure 13 is a cross-sectional view taken along the line E-E in Figure 12.

[0076] In the first embodiment, the flow of the reformed gas G1 in the first reaction chamber 41 is not particularly specified. In the fifth modification, the case where the flow of the reformed gas G1 in the first reaction chamber 41 becomes a forward vortex flow and the case where the flow of the reformed gas G1 in the first reaction chamber 41 becomes a reverse vortex flow will be described.

[0077] First, we will explain an example of the configuration of the gas reforming device 100 for making the flow of the to-be-reformed gas G1 a forward vortex flow in the first reaction chamber 41. In the gas reforming device 100 shown in Fig. 12, gas inlet ports 51 are provided at two locations on the side of the reaction vessel 2 at the end on the side where the first electrode 31 is disposed (the +Z direction side).

[0078] 13, the reaction vessel 2 has a cylindrical shape with end faces at both ends. The gas inlet 51 is shaped so that the to-be-reformed gas G1 flows along the inner wall surface of the first reaction chamber 41. Specifically, as shown in FIG. 13, the gas inlet 51 is formed so that the opening of the gas inlet 51 faces the tangential direction of the inner wall surface of the reaction vessel 2 when viewed from the symmetrical axis direction (Z direction) of the reaction vessel 2. However, the structure for causing the to-be-reformed gas G1 flowing from the gas inlet 51 to flow 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 include a separate member for directing the flow of the to-be-reformed gas G1 flowing from the gas inlet 51 along the inner wall surface of the first reaction chamber 41.

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

[0080] 12, the second electrode 32 has a conical inner wall whose inner diameter narrows toward the second reaction chamber 42 (the −Z direction side). With this configuration, the to-be-reformed gas G1 can be made to flow into the second reaction chamber 42 by increasing the flow rate while maintaining the vortex flow of the to-be-reformed gas G1.

[0081] The number of gas inlets 51 does not necessarily have to be two; one gas inlet may be provided. Furthermore, more than two gas inlets 51 may be provided. However, providing multiple gas inlets 51 allows for more stable forward vortex flow than providing a single gas inlet 51. When providing multiple gas inlets 51, the gas inlets 51 are preferably arranged so as to be rotationally symmetric with respect to the axis of symmetry of the reaction vessel 2 when viewed from the axial direction of symmetry (Z direction) of the reaction vessel 2. Here, rotational symmetry refers to a configuration in which the arrangement of the gas inlets 51 overlaps when rotated (360° / n) around the axis of symmetry (Z1 axis) of the reaction vessel 2, where n is an integer of 2 or greater. Arranging the gas inlets 51 so as to be rotationally symmetric with respect to the axis of symmetry of the reaction vessel 2 when viewed from the axial direction of symmetry (Z direction) of the reaction vessel 2 allows for more stable forward vortex flow.

[0082] Furthermore, Figure 13 shows an example in which the reformed gas G1 swirls clockwise when viewed in the direction from the first reaction chamber 41 to the second reaction chamber 42 (-Z direction), but the direction in which the reformed gas G1 swirls may also be the opposite direction.

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

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

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

[0086] The reformed gas 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 axis of symmetry (Z1 axis) of the cylindrical reaction vessel 2. After reaching the inner wall of the first reaction chamber 41 on the first electrode 31 side (+Z direction side), the reformed gas flows toward the opening 52 side (-Z direction side) along the center 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 flow is generated inside the first reaction chamber 41.

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

[0088] Furthermore, even when the flow of the reformed gas G1 in the first reaction chamber 41 is a reverse vortex, the reformed gas G1 can be retained in the first reaction chamber 41 for a longer period of time than when no vortex is generated.

[0089] Note that even when the flow of the reformed gas G1 in the first reaction chamber 41 is a reverse vortex flow, there are no limitations on the number of gas inlets 51 and the swirling direction of the vortex flow. In order to generate a reverse vortex flow more stably, it is preferable that the gas inlets 51 are provided so as to be rotationally symmetrical with respect to the axis of symmetry of the reaction vessel 2 when viewed from the direction of the symmetry axis of the reaction vessel 2 (Z direction).

[0090] Furthermore, in the case where the reaction vessel 2 has a structure having a partition 21 separating 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 of the reaction vessel 2 that contacts the partition 21.

[0091] According to the gas reforming apparatus 100 of the fifth modification, the plasma P is stably maintained away from the inner wall of the first reaction chamber 41 (closer to the Z1 axis), which has the effect of making it easier to maintain a high temperature state of the plasma P. Furthermore, according to the gas reforming apparatus 100 of the fifth modification, the plasma P maintained at a high temperature state can be made to reach the third electrode 33, which further increases the reaction efficiency between the reformed gas G1 and the reaction accelerator 7.

[0092] Furthermore, according to the gas reforming device 100 of variant example 5, the vortex current causes the reformed gas G1 to remain in the first reaction chamber 41 for a longer period of time, thereby extending the time that the reformed gas G1 comes into contact with the plasma P and improving the reforming efficiency of the reformed gas G1.

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

[0094] In the first embodiment, it has been described that the material constituting the reaction vessel 2 is preferably a material with high insulating properties and durability. However, the reaction vessel 2 may be made of a material containing a metal as long as the first electrode 31, the second electrode 32, and the third electrode 33 are electrically insulated from each other.

[0095] Fig. 15 shows an example in which the portion of the reaction vessel 2 that forms the second reaction chamber 42 is made of a material containing 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 of the first embodiment, and therefore a 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. An insulating portion 2b is interposed between the second main body 2c and the second electrode 32, so the second main body 2c and the second electrode 32 are electrically insulated from each other. The third electrode 33 and the second electrode 32 are also electrically insulated from each other.

[0097] The type of metal constituting the second main body portion 2c is not particularly limited. For example, tungsten can be used as the metal constituting the second main body portion 2c in order to improve the heat resistance of the gas reforming apparatus 100. Furthermore, aluminum can be used as the metal constituting the second main body portion 2c in order to reduce the weight of the gas reforming apparatus 100.

[0098] The insulating material constituting the insulating portion 2b is not particularly limited. Examples of insulating materials constituting the insulating portion 2b include glass, ceramics, and resin. Specific examples of glass constituting the insulating portion 2b include quartz glass and borosilicate glass. Specific examples of ceramics constituting the insulating portion 2b include alumina (Al ２ O ３ ), zirconia (ZrO ２ ), magnesia (MgO). Specific examples of the resin that forms the insulating portion 2b include PTFE (polytetrafluoroethylene) and PEEK (polyetheretherketone).

[0099] According to the gas reforming apparatus 100 of the sixth modification, the reaction vessel 2 is made of a material containing metal, which has the effect of imparting functions to the reaction vessel 2 according to the characteristics of the metal, such as heat resistance or light weight.

[0100] Second Embodiment The configuration of a gas reforming apparatus 200 according to a second embodiment will be described with reference to Figures 16 and 17. As a fourth modification of the gas reforming apparatus 100 according to the first embodiment, a case has been described in which the second reaction chamber 42 is arranged so as to be lower in the direction of gravity than the first reaction chamber 41. The gas reforming apparatus 200 according to the second embodiment will be described as a configuration example in which the first reaction chamber 41 is arranged lower in the direction of gravity than the second reaction chamber 42. Therefore, explanations of points common to the gas reforming apparatus 100 according to the first embodiment will be omitted or simplified. Furthermore, the same reference numerals are used for components common to the gas reforming apparatus 100 according to the first embodiment.

[0101] Similar to the gas reformer 100 of the first embodiment, the gas reformer 200 of the present embodiment includes a reaction vessel 2, a first electrode 31, a second electrode 32, a third electrode 33 serving as an extraction electrode, and a reaction accelerator 7. The reaction vessel 2 also includes a first reaction chamber 41 and a second reaction chamber 42.

[0102] Fig. 16 is a cross-sectional view showing a gas reforming apparatus 200 according to the second embodiment. Fig. 17 is a cross-sectional view taken along the line F-F shown in Fig. 16. In Fig. 16 and Fig. 17, the direction from the first reaction chamber 41 toward the second reaction chamber 42 (+Z direction) corresponds to the upward direction of gravity.

[0103] In the gas reforming apparatus 200 according to the second embodiment, the reaction accelerator 7 is also disposed inside the second reaction chamber 42, which is thermally separated from the first reaction chamber 41, and therefore the reaction accelerator 7 can be maintained at a high temperature. Therefore, the gas reforming apparatus 200 according to the second embodiment can efficiently reform the reformed gas G1.

[0104] 16 , in the gas reforming apparatus 200 according to the second embodiment, the second reaction chamber 42 is located above the first reaction chamber 41 in the direction of gravity (+Z direction). The third electrode 33, which is an extraction electrode, is disposed in the second 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 direction of gravity, in addition to the gas outlet 53.

[0105] 16 and 17 , a through-hole 331 through which the to-be-reformed gas G1 passes is provided in the tip portion 33a of the third electrode 33. Note that the shape of the third electrode 33 in this embodiment is merely an example, and for example, the cross-sectional shape of the tip portion 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. Furthermore, 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] If the reaction accelerator 7 is a substance that is consumed in the process of reforming the reformed gas G1, the reaction accelerator 7 needs to be supplied to the third electrode 33 in order to maintain the reforming efficiency of the reformed gas G1 by the gas reforming device 200. For example, if the reaction accelerator 7 is carbon and the CO contained in the reformed gas G1 is ２ When CO is produced from C, carbon is consumed as shown in formula (4) below: C + CO ２ ←→2CO ‥‥(4)

[0107] In the gas reforming apparatus 200 according to the second embodiment, when the reaction accelerator 7 is introduced through the inlet 9, which is provided above the third electrode 33 in the direction of gravity (in the +Z direction), the reaction accelerator 7 is supplied to the third electrode 33 by gravity. Therefore, according to the gas reforming apparatus 200 according to the second embodiment, the reaction accelerator 7 can be easily supplied to the third electrode 33 without stopping the operation of the gas reforming apparatus 200.

[0108] 16 and 17 is merely an example, and various variations can be adopted for the gas reforming apparatus 200 of this embodiment. The structure of the modified example will be described below with reference to the drawings.

[0109] Modification A modification of the second embodiment will be described with reference to Figures 18 and 19. Figure 18 is a cross-sectional view showing a gas reforming apparatus 200 according to a modification of the second embodiment. Figure 19 is a cross-sectional view taken along the line G-G shown in Figure 18. Note that Figure 16 will also be referenced to explain the effects of the modification of the second embodiment.

[0110] 18 and 19 , in a gas reforming apparatus 200 according to a modified example, 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, if the insulating member 8 is made of the same type of insulating material as the reaction vessel 2, the insulating member 8 may be configured integrally with the reaction vessel 2. Furthermore, it is not essential that the insulating member 8 be attached to the reaction vessel 2; the insulating member 8 may be attached to the second electrode 32 or the third electrode 33.

[0111] 18 and 19 , the insulating member 8 has a ring shape. However, the shape of the insulating member 8 is just an example and is not limited to a ring shape. For example, if the opening of the opening 52 has a rectangular shape, the insulating member 8 may have a rectangular opening.

[0112] The insulating material constituting the insulating member 8 is not particularly limited. Examples of insulating materials constituting the insulating member 8 include glass, ceramics, and resin. Specific examples of glass constituting the insulating member 8 include quartz glass and borosilicate glass. Specific examples of ceramics constituting the insulating member 8 include alumina (Al ２ O ３ ), zirconia (ZrO ２ ), magnesia (MgO). Specific examples of the resin that forms the insulating member 8 include PTFE and PEEK.

[0113] The effects of the gas reforming apparatus 200 according to the modified example of the second embodiment will be described in comparison with the gas reforming apparatus 200 according to the second embodiment. In the gas reforming apparatus 200 according to the second embodiment, the third electrode 33 is disposed at a distance from the second electrode 32 so as not to come into contact with it (see FIG. 16 ). Therefore, the reformed gas G1 flowing in from the opening 52 can travel toward the gas outlet 53 through two paths: one that passes through the through-hole 331 and one that passes between the second electrode 32 and the third electrode 33.

[0114] Here, in order to increase the reforming efficiency of the reformed gas G1, it is desirable to bring the reformed gas G1 into contact with the reaction accelerator 7 as much as possible. The reformed gas G1 can be brought into contact with the reaction accelerator 7 more efficiently when the reformed gas G1 passes through the through-holes 331 rather than between the second electrode 32 and the third electrode 33.

[0115] In the gas reforming device 200 according to the modified example, an insulating member 8 is arranged between the second electrode 32 and the third electrode 33 to prevent the reformed gas G1 from passing between the second electrode 32 and the third electrode 33 and to allow more of the reformed gas G1 to pass through the through hole 331.

[0116] In the gas reforming apparatus 200 according to the modified example, a larger amount of the reformed gas G1 can be allowed to flow into the through-holes 331 compared to a case in which the insulating member 8 is not provided. Therefore, according to the gas reforming apparatus 200 according to the modified example, the reformed gas G1 can be efficiently brought into contact with the reaction accelerator 7, and the reforming efficiency of the reformed gas G1 can be improved.

[0117] The insulating member 8 may be arranged in any manner as long as it is capable of preventing the reformed gas G1 from passing between the second electrode 32 and the third electrode 33 and allowing a larger amount of the reformed gas G1 to flow into the through-holes 331. For example, a gap may be present between the insulating member 8 and the second electrode 32 or between the insulating member 8 and the third electrode 33. In other words, it is not essential that all of the reformed gas G1 flowing in from the openings 52 flow into the through-holes 331.

[0118] The first and second embodiments of the present disclosure have been described above. The present disclosure is not limited to the above examples, and appropriate design changes can be made within the scope of the configuration of the present disclosure. For example, it is possible to modify, add, or omit at least one configuration element in the present disclosure, or to extract at least one component element and combine it with a component element of another embodiment.

[0119] The gas reforming device according to the present disclosure can reform highly harmful substances contained in the reformed gas into less harmful substances, thereby contributing to Goal 3 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Ensure healthy lives and promote well-being for all at all ages."

[0120] Furthermore, the gas reforming device according to the present disclosure can reform the reformed gas into a substance that can be used as a fuel, and therefore contributes to Goal 7 of the United Nations-led Sustainable Development Goals (SDGs), which is to "ensure access to affordable, reliable, sustainable, and modern energy for all."

[0121] Furthermore, the gas reforming apparatus according to the present disclosure can reform a gas to be reformed that has a high global warming potential into a substance with a low global warming potential, thereby contributing to Goal 13 of the United Nations-led Sustainable Development Goals (SDGs), which is to "take urgent action to combat climate change and its impacts."

[0122] 100, 200 Gas reforming device 2 Reaction vessel 21 Partition portion 2a First main body portion 2b Insulating portion 2c Second main body portion 31 First electrode 32 Second electrode 33 Third electrode (extraction electrode) 33a Tip portion 33b Shaft portion 331 Through hole 41 First reaction chamber 42 Second reaction chamber 51 Gas inlet 52 Opening portion 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 Gas after reforming P Plasma

Claims

1. A gas reforming device comprising: a reaction vessel having a first reaction chamber into which a gas to be reformed flows, and a second reaction chamber, thermally separated from the first reaction chamber, into which the gas to be reformed that has passed through the first reaction chamber flows; a first electrode and a second electrode provided within the first reaction chamber for generating plasma within the first reaction chamber; an extraction electrode provided within the second reaction chamber for extracting the plasma from the first reaction chamber into the second reaction chamber; and a reaction accelerator disposed on the extraction electrode.

2. A gas reforming device as described in claim 1, wherein the reaction vessel is provided with a partition that thermally separates the first reaction chamber and the second reaction chamber, and the partition is formed with an opening that connects the first reaction chamber and the second reaction chamber.

3. The gas reforming apparatus according to claim 2, wherein the second electrode is disposed in the partition.

4. The gas reforming apparatus according to claim 1, wherein the second electrode is formed with an opening that connects the first reaction chamber with the second reaction chamber.

5. The gas reforming device according to any one of claims 2 to 4, wherein the extraction electrode is provided at a position opposite to the opening.

6. A gas reforming device according to any one of claims 2 to 5, wherein the reaction accelerator is disposed on a portion of the extraction electrode that faces the opening.

7. A gas reforming apparatus according to any one of claims 2 to 6, wherein the reaction vessel is axially symmetric.

8. The gas reforming apparatus according to claim 7, wherein the opening is formed on an axis of symmetry of the reaction vessel.

9. A gas reforming device as described in claim 7 or claim 8, wherein a gas inlet for flowing the reformed gas into the first reaction chamber is provided at the end of a side of the reaction vessel on the side where the first electrode is disposed, and the reaction vessel is structured so that the reformed gas flowing in from the gas inlet flows along the inner wall surface of the first reaction chamber.

10. The gas reforming apparatus according to claim 9, wherein the gas inlet is provided in a plurality of locations so as to be rotationally symmetrical about the axis of symmetry of the reaction vessel when viewed from the direction of the axis of symmetry of the reaction vessel.

11. A gas reforming device as described in claim 2 or claim 3, wherein the reaction vessel has an axially symmetric shape, a gas inlet for allowing the reformed gas to flow into the first reaction chamber is provided on a side surface of the reaction vessel so as to contact the second electrode or the partition portion, and the reaction vessel has a structure in which the reformed gas flowing in from the gas inlet flows along the inner wall surface of the first reaction chamber.

12. The gas reforming apparatus according to claim 11, wherein a plurality of the gas inlets are provided so as to be rotationally symmetrical about the axis of symmetry of the reaction vessel when viewed from the direction of the axis of symmetry of the reaction vessel.

13. A gas reforming device according to any one of claims 1 to 12, wherein the first reaction chamber is provided above the second reaction chamber in the direction of gravity, and the tip surface of the extraction electrode is recessed when viewed from above in the direction of gravity.

14. A gas reforming device as described in any one of claims 1 to 12, wherein the second reaction chamber is provided above the first reaction chamber in the direction of gravity, and the extraction electrode has a through hole that allows the reformed gas flowing into the second reaction chamber to pass through.

15. A gas reforming device as described in any one of claims 2 to 12, wherein the second reaction chamber is provided above the first reaction chamber in the direction of gravity, the extraction electrode has a through hole that allows the reformed gas flowing into the second reaction chamber to pass through, and the extraction electrode is positioned so that the through hole faces the opening.

16. A gas reforming device as described in claim 14 or claim 15, wherein an insulating member is disposed between the second electrode and the extraction electrode to prevent the reformed gas from passing between the second electrode and the extraction electrode.

17. A gas reforming apparatus according to any one of claims 1 to 16, wherein the reaction vessel is comprised of a metal, and the first electrode and the second electrode, the first electrode and the extraction electrode, and the second electrode and the extraction electrode are electrically insulated from each other.

18. A gas reforming apparatus according to any one of claims 1 to 17, wherein the tip of the first electrode is ring-shaped.

19. A gas reforming apparatus according to any one of claims 1 to 18, wherein the reaction promoter is a catalyst.

20. A gas reforming apparatus according to any one of claims 1 to 18, wherein the gas to be reformed contains carbon dioxide, and the reaction accelerator contains carbon.

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