JP2010184197A - Plasma reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma reactor capable of efficiently generating a gas containing hydrogen even if the temperature of a reformed raw material gas is low. <P>SOLUTION: The plasma reactor 100 includes an outer frame body 1 where an inflow port 2 and an outflow port 3 are formed and a partition wall 14 that comparts and forms a channel 13 penetrating from one end 11 to the other end 12, and includes a cylindrical reactor body 21 that is disposed inside the outer frame body 1 such that a part of the partition wall 14 is a plasma generation electrode, and a fluid that inflows from the inflow port 2 outflows from one end 11, passes through a channel 13, outflows from the other end 12, and further outflows from the outflow port 3, an introductory channel 31 that is formed so as to be along at least a part of a side 22 of the reactor body and introduces the fluid that inflows from the inflow port 2 to one end 11 of the reactor body 21 while allowing the fluid to flow along the side of the reactor body 21, a heater 35 that is disposed on a portion along the introductory channel 31 inside the side 22 of the reactor body, and an introductory channel heater 32 that is disposed in the introductory channel 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma reactor, and more particularly to a plasma reactor that can efficiently generate a hydrogen-containing gas even when the temperature of a reforming raw material gas is low.

  In recent years, hydrogen has attracted attention as a clean energy. As a process for obtaining this hydrogen, a reforming reaction of hydrocarbons or the like is known. In general, the reforming reaction of hydrocarbons or the like is performed at a high temperature of 700 to 900 ° C., and there are problems of increasing the size of the plasma reactor, starting time, and starting energy.

  On the other hand, a method of generating a low temperature plasma by applying a voltage between electrodes arranged in the reaction apparatus and performing a gas reforming reaction using this low temperature plasma is disclosed (for example, patents). References 1 and 2).

JP 2001-314748 A JP-A-2005-247638

  The plasma reactors described in the cited documents 1 and 2 are intended to efficiently reform the gas at a low temperature. However, if the temperature of the raw material gas is low, the reforming of the gas cannot be performed efficiently. There was a problem. Further, if the raw material gas is preheated, it is necessary to provide an external heater, which increases the overall size of the plasma reactor and requires a large space. In addition, when the raw material gas is preheated outside, the temperature decreases when the heated gas is transferred to the plasma reactor, so it is necessary to heat it higher than the target temperature. There was another problem that it was necessary.

  The present invention has been made in view of such problems of the prior art, and even when the temperature of the reforming raw material gas (hereinafter sometimes referred to as a unit “raw material gas”) is low, the hydrogen-containing gas is efficiently produced. It is intended to provide a plasma reactor capable of generating

  In order to solve the above-described problems, the present invention provides the following plasma reactor.

[1] An outer frame in which an inlet that is an inlet for allowing fluid to flow in and an outlet that is an outlet for allowing fluid to flow to the outside are formed, and the other frame from which one fluid flows out from the other end. A partition wall defining a flow path penetrating to the end, a part of the partition wall is a plasma generating electrode, and the fluid flowing in from the inflow port flows into the flow path from the one end portion. A cylindrical reactor body disposed inside the outer frame body so as to pass through the flow path and flow out from the other end, and further flow out from the outflow port, and the reactor An introduction path that is formed along at least a part of the side surface of the main body and guides the fluid flowing in from the inlet to the one end of the reactor body while flowing along the side surface of the reactor body; , A portion along the introduction path in the side surface of the reactor main body Plasma reactor comprising a disposed a heater, and an introduction path heater disposed in the introduction passage.

[2] The plasma reactor according to [1], wherein the heater and the introduction path heater are plate-shaped heating plates, and the introduction path is surrounded by the heating plate.

[3] A plasma generation power source for applying a voltage to the plasma generation electrode is provided, and a plasma can be generated in the reactor body by applying a pulse voltage to the plasma generation electrode from the plasma generation power source. The plasma reactor according to [1] or [2].

[4] The plasma reactor according to any one of [1] to [3], wherein a catalyst is supported on the reactor main body.

[5] The catalyst is selected from the group consisting of noble metals, aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, and barium. The plasma reactor according to [4], which is made of a material containing at least one element.

[6] The plasma reactor according to [4], wherein the catalyst is made of a substance containing at least one element selected from the group consisting of platinum, rhodium, palladium, ruthenium, indium, silver and gold.

[7] The plasma reactor according to any one of [3] to [6], wherein the plasma generation power source is a high voltage pulse power source using an electrostatic induction thyristor.

  In the plasma reactor of the present invention, the introduction path is formed along at least a part of the side surface of the reactor body, and the introduction path heater is disposed in a portion along the introduction path in the side surface of the reactor body. Therefore, both the reactor main body and the introduction path can be heated by the introduction path heater formed along the side surface of the reactor main body. Furthermore, since the introduction path is formed along the side surface of the reactor main body, the reactor main body and the introduction path are disposed adjacent to each other in the outer frame body, so that the introduction path is heated. Thus, the reactor main body can also be heated, and the heating necessary for the reforming reaction can be performed efficiently. Thus, even when the temperature of the reforming raw material gas is low, the reforming raw material gas is efficiently heated and introduced into the reactor main body when passing through the introduction path in the plasma reactor. Therefore, even when the temperature of the reforming raw material gas is low, the hydrogen-containing gas can be generated efficiently.

1 is a perspective view schematically showing one embodiment of a plasma reactor of the present invention. It is a schematic diagram which shows the cross section which cut | disconnected the plasma reactor shown in FIG. 1 so that a reactor main body might be included in the plane parallel to the flow path of a reactor main body. It is a schematic diagram which shows the cross section orthogonal to the flow path of the reactor main body which comprises one Embodiment of the plasma reactor of this invention. It is a schematic diagram which shows the A-A 'cross section of FIG. 3A.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following embodiments, and is within the scope of the present invention. It should be understood that design changes, improvements, and the like can be made as appropriate based on the general knowledge of vendors.

1. Plasma reactor:
As shown in FIGS. 1 and 2, the plasma reactor 100 of the present embodiment has an outer frame in which an inlet 2 that is an inlet for allowing fluid to flow into the interior and an outlet 3 that is an outlet for allowing fluid to flow to the outside are formed. And a partition wall 14 that partitions the body 1 and a flow path 13 that penetrates from one end portion (inflow side end portion) 11 into which the fluid flows into the other end portion (outflow side end portion) 12 from which the fluid flows out. A part of the partition wall 14 is a plasma generating electrode, and the fluid flowing in from the inflow port 2 flows into the flow path 13 from one end portion 11, passes through the flow path 13, and passes through the other end portion 12. It is formed so as to extend along at least a part of the cylindrical reactor main body 21 disposed inside the outer frame 1 so as to flow out from the outflow port 3 and the side surface 22 of the reactor main body 21, The fluid flowing in from the inlet 2 flows along the side surface 22 of the reactor main body 21. An introduction path 31 that leads to one end 11 of the reactor main body 21, a heater 35 disposed in a portion along the introduction path 31 in the side surface 22 of the reactor main body 21, and the introduction path 31. The introduction path heater 32 is provided. Here, FIG. 1 is a perspective view schematically showing one embodiment of the plasma reactor 100 of the present invention, and FIG. 2 shows the plasma reactor 100 shown in FIG. 1 parallel to the flow path of the reactor main body. It is a schematic diagram which shows the cross section cut | disconnected so that the reactor main body might be included in the plane. In the plasma reactor 100 shown in FIG. 1, a plate constituting one surface of the outer frame body is removed so that the state inside the outer frame body can be observed. Therefore, the plasma reactor 100 has a plate disposed on all six surfaces of a rectangular parallelepiped outer frame. The arrows in FIG. 2 indicate the flow direction of the fluid (source gas, reformed gas).

Thus, in the plasma reactor of the present embodiment, the introduction path 31 is formed along at least a part of the side surface 22 of the reactor main body, and the heater 35 is connected to the introduction path 31 in the side surface 22 of the reactor main body. Since the heater 35 is formed along the side surface 22 of the reactor main body, both the reactor main body 21 and the introduction path 31 can be heated. . Furthermore, since the reactor main body 21 and the introduction path 31 are disposed adjacent to each other in the outer frame body 1, the reactor main body 21 can also be heated by heating the introduction path 31, and the reforming reaction Can be efficiently performed. Thus, even when the temperature of the reforming raw material gas is low, the reforming raw material gas is efficiently heated and introduced into the reactor main body 21 when passing through the introduction path 31 in the plasma reactor 100. . Therefore, even when the temperature of the reforming raw material gas is low, the hydrogen-containing gas can be generated efficiently. Here, reforming the raw material gas means that hydrogen is generated by reacting hydrocarbons or alcohol in the raw material gas, and obtaining a hydrogen-containing mixture from the raw material gas. Therefore, the raw material gas reformed by the plasma reactor of the present invention contains hydrocarbons or alcohols. The reforming reaction may be a partial oxidation reaction, a steam reforming reaction, or the like. The partial oxidation reaction is, for example, a reaction represented by a reaction formula of “CH ₄ + 1/2 · O ₂ = 2H ₂ + CO” when reforming methane. The steam reforming reaction is, for example, a reaction represented by a reaction formula of “CH ₄ + H ₂ O = 3H ₂ + CO” when reforming methane. The plasma reactor of the present embodiment causes such a reforming reaction to be generated by plasma generated in the reactor main body.

  In the plasma reactor 100 of the present embodiment, the outer frame body 1 is a rectangular parallelepiped box-shaped container, and the outlet 3 is opened on one surface, and one on each of a pair of opposed surfaces in the other surface. Each inlet 2 is open. Two inflow ports 2 may be provided as described above, but only one inflow port 2 may be provided. Three or more may be provided. In the plasma reactor 100 of the present embodiment, as shown in FIGS. 1 and 2, the raw material gas flows in from the two inlets 2, and the raw material gas that flows in passes through the two introduction paths 31. The raw material gases that have been transferred to one end (inflow side end) 11 and flowed in from the two inlets 2 merge at one end (inflow side end) 11 of the reactor body 21, The merged source gas is formed so as to flow into the flow path 13 from one end portion (inflow side end portion) 11 of the reactor main body 21. Since two inflow ports 2 are formed, it is possible to reform more raw material gas than when one inflow port 2 is formed.

  As shown in FIGS. 1 and 2, the position where the inflow port 2 is formed in the outer frame 1 is the other end of the reactor main body 21 when the reactor main body 21 is mounted in the outer frame 1 ( A position close to the outflow side end) 12 is preferred. Thereby, as shown in FIGS. 1 and 2, the introduction path 31 is arranged so that the raw material gas flows from the one end portion 11 toward the other end portion 12 along the side surface 22 of the reactor main body. Thus, the raw material gas flowing in from the inflow port 2 can be heated using the entire portion from the end on the one end 11 side to the end on the other end 12 side of the side surface 22 of the reactor main body. Further, since the inlet 2 is formed at a position close to the other end (outlet end) 12 of the reactor main body 21, the distance from the inlet 2 to the other end 12 of the introduction path 31. The heating by the introduction path heater 32 can be reduced, and the heating amount as a whole can also be reduced. As shown in FIGS. 1 and 2, the surface (wall) on which the inlet 2 of the outer frame 1 is formed is closest to the side surface 22 of the reactor main body on which the heater 35 is disposed. A surface parallel to the side surface 22 of the main body is preferable. And although the distance from the inflow port 2 to the side surface 22 of a reactor main body changes with the thickness of the heat insulating material 33, it is preferable that they are 5 mm-40 mm, and it is still more preferable that they are 10 mm-30 mm. When shorter than 5 mm, the heat insulation effect of the reactor main body by the heat insulating material 33 may fall. On the other hand, if the length is longer than 40 mm, the plasma reactor 100 itself becomes large, which causes a problem that it is difficult to install in a small space.

  Further, as shown in FIGS. 1 and 2, the position where the outflow port 3 is formed in the outer frame 1 is the other end of the reactor main body 21 when the reactor main body 21 is mounted in the outer frame 1. It is preferable that it is the position of the front of the part (outflow side edge part) 12. Thereby, the gas after the reforming reaction that has flowed out from the other end portion (outflow side end portion) 12 of the reactor main body 21 can flow out of the plasma reactor 100 with a small resistance.

  The shape of the inflow port 2 is not particularly limited, and may be a polygon such as a quadrangle, a circle, an ellipse, or any other irregular shape. In addition, the shape of the outlet 3 is not particularly limited, and can be a polygon such as a quadrangle, a circle, an ellipse, or any other irregular shape, but in order to reduce the resistance of the gas flow after reforming, The shape of the end face of the other end (outlet end) 12 of the reactor main body 21 is preferably the same.

  The shape of the outer frame body 1 is preferably a rectangular parallelepiped as described above, but is not limited to this as long as the reactor main body and the introduction path can be disposed therein, and a cylindrical shape and a cylindrical shape whose bottom surface is a polygon other than a square shape. The bottom surface may be an elliptical cylinder or the like. The material of the outer frame body 1 is not particularly limited, but is preferably a metal having good workability (for example, stainless steel). Further, when the plasma generating electrode is disposed in the reactor main body, it is necessary to prevent a short circuit. Therefore, a plate-like (sheet-like) shape made of an insulating material is formed on a portion of the outer frame 1 that contacts the reactor main body. It is preferable to provide an insulator. In particular, the electrode installation portion (in the vicinity of the terminal) of the reactor main body is preferably made of an insulating material. Ceramics can be suitably used as the insulating material. As the ceramic, for example, alumina, zirconia, silicon nitride, aluminum nitride, sialon, mullite, silica, cordierite, or the like is preferably used. The thickness of the outer frame wall is not particularly limited as long as it can withstand the use of the plasma reactor.

  When using the plasma reactor 100 of the present embodiment, a hollow pipe for circulating the source gas and the reformed gas is connected to the inlet 2 and the outlet 3 of the outer frame 1. There are no particular restrictions. For example, a cylindrical or rectangular tube structure can be used. The size can be appropriately determined depending on the use of the plasma reactor 100. The material of the pipe is not particularly limited, but is preferably a metal having good workability (for example, stainless steel).

  In the plasma reactor 100 of the present embodiment, as shown in FIGS. 1 and 2, the reactor main body 21 includes the other end (the inflow side end) 11 through which the fluid flows out, It is a cylindrical body having a partition wall 14 that defines a flow path 13 that penetrates to the outflow side end portion 12. In the reactor main body 21, the fluid that has flowed in from the inlet 2 flows into the flow path 13 from one end 11, and further passes through the flow path 13 and flows out from the other end 12. 3 is disposed inside the outer frame 1 so as to flow out of the outer frame 1.

  The outer shape of the reactor main body 21 is preferably a rectangular parallelepiped as shown in FIGS. 1 and 2, but the bottom surface may be other shapes such as a polygonal columnar shape other than a square shape or a cylindrical shape. In addition, as the shape of the flow path, a desired shape may be appropriately selected from a circle, an ellipse, a triangle, a quadrangle, and other polygons in a cross section orthogonal to the central axis. In the plasma reactor 100 of the present embodiment, the shape of the flow channel is a quadrangle in a cross section orthogonal to the central axis.

  The length of the reactor main body 21 (the length in the direction in which the flow channel extends (center axis direction)) is appropriately selected depending on the application, but is preferably 5 mm to 100 mm, and preferably 10 mm to 50 mm. Further preferred. If it is shorter than 5 mm, most of the raw material gas may flow out of the reactor main body 21 without being reformed. When the length is longer than 100 mm, the reactor main body 21 becomes large, so that the entire plasma reactor becomes large, and may not be suitable for applications such as an in-vehicle raw material gas reformer that is required to be small and lightweight.

  The reactor body 21 is a part of the partition wall 14 which is a plasma generating electrode, and can generate plasma in the reactor body 21 by applying a pulse voltage to the plasma generating electrode. By generating plasma in the reactor main body 21, the raw material gas can be efficiently reformed without being heated to a high temperature.

  3A and 3B show a reactor main body 21 in which a plasma generating electrode is disposed. The reactor body 21 is formed by hierarchically laminating a plurality of plate electrodes 41 at intervals in a cylindrical ceramic dielectric 43. The plate electrode 41 is the plasma generating electrode. The plate electrode 41 is formed of a plate-shaped ceramic dielectric 43 having a conductive film 42 embedded therein, and generates a plasma in the flow path 13 opened between the plate electrodes by applying a pulse voltage between the plate electrodes. Can do. The spacers 44 are disposed between the plate electrodes, so that the flow path 13 is formed between the plate electrodes. The plate electrode 41 and the spacer 44 correspond to the partition wall 14. FIG. 3A is a schematic view showing a cross section of the reactor main body 21 constituting one embodiment of the plasma reactor according to the present invention perpendicular to the flow path 13. FIG. 3B is a schematic diagram illustrating the A-A ′ cross section of FIG. 3A.

  The distance between the flat plate electrodes 41 is preferably 0.05 to 50 mm, and more preferably 0.1 to 10 mm. If it is larger than 50 mm, there is a problem that plasma is hardly generated between the plate electrodes even if the input power is increased. Although the thickness of the flat electrode 41 is not specifically limited, 0.1-5 mm is preferable and 0.2-3 mm is still more preferable. If it is smaller than 0.1 mm, it may not be possible to ensure electrical insulation between a pair of adjacent unit electrodes (plasma generating electrodes). If it is larger than 5 mm, miniaturization will be hindered and the distance between the electrodes will be reduced. The increase in load voltage due to the increase in length may lead to a decrease in efficiency.

  The reactor body 21 is preferably an integrally sintered body formed by integrally firing including the flat plate electrode 41. The flat plate electrode 41 (basic electrode) before lamination is preferably a sintered body obtained by sintering an integrally fired body such as a ceramic molded body, a degreased body, and a calcined body.

  The ceramic dielectric 43 constituting the plate electrode 41 is preferably a material having a high dielectric constant. For example, aluminum oxide, zirconium oxide, silicon oxide, mullite, cordierite, spinel, titanium-barium oxide, magnesium- Calcium-titanium-based oxides, barium-titanium-zinc-based oxides, silicon nitride, aluminum nitride, and the like can be suitably used. Among these materials, it is preferable to appropriately select materials suitable for generating plasma having a strength suitable for the reaction of each component of the source gas, and combine them to form a plate electrode. Further, by using a material having excellent thermal shock resistance as a main component, the plasma generating electrode can be operated even under high temperature conditions. The spacer disposed between the flat plate electrodes 41 is preferably made of the same material as the ceramic dielectric 43 of the flat plate electrode 41.

  The buried electrode (conductive film 42) is preferably a highly conductive metal, for example, at least one selected from the group consisting of iron, gold, silver, copper, titanium, aluminum, nickel, chromium, tungsten, and molybdenum. A metal or alloy containing these components can be preferably exemplified. The thickness of the conductive film 42 is preferably 0.001 to 0.1 mm, and more preferably 0.005 to 0.05 mm. If it is smaller than 0.001 mm, it is difficult to produce a uniform conductive film, which may cause local plasma generation, and if it is larger than 0.1 mm, it may be difficult to ensure adhesion. The conductive film 42 embedded in the ceramic dielectric 43 extends to the end of the plate electrode 41 (extends until it can come into contact with the outside) to form a terminal. Since a plurality of the plate electrodes 41 are laminated, it is preferable that the terminals of the plurality of plate electrodes 41 are integrally formed to form the terminal aggregate portion 45. It is preferable to generate plasma by applying a voltage to the terminal assembly 45. Thereby, it is possible to distribute and process many gases simultaneously.

  In the plasma reactor 100 of the present embodiment, a plasma generating power source (pulse power source) is connected to the terminal assembly 45 of the reactor main body 21, a voltage is applied by the plasma generating power source (pulse power source), and the source gas is converted into plasma. It is preferable to process. A pulse power supply is a power supply that applies a pulse voltage to a pair of electrodes. Any power source in which a voltage is periodically applied can be used. Among them, (a) a pulse waveform with a peak voltage of 1 kV or more and a pulse number of 1 or more per second, (b) an AC voltage waveform with a peak voltage of 1 kV or more and a frequency of 1 or more, (c) voltage Is preferably a power supply capable of supplying a DC waveform of 1 kV or more, or (d) a voltage waveform formed by superimposing any of these. The pulse power supply preferably has a peak voltage of 1 to 20 kV, and more preferably has a peak voltage of 5 to 10 kV. The pulse width is preferably about 50 to 30 ns as a full width at half maximum. As such a pulse power source, for example, a high voltage pulse power source (manufactured by NGK Corporation) using an electrostatic induction thyristor (SI thyristor) can be exemplified.

  In the plasma reactor 100 of the present embodiment, it is preferable that a catalyst is supported on the reactor main body 21. The catalyst is preferably supported on the surface of the plate electrode 41. The catalyst can be used without particular limitation as long as it is a substance that acts as a catalyst. For example, at least one element selected from the group consisting of noble metals, aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, and barium. The substance to contain can be mentioned. Examples of the noble metal include platinum, rhodium, palladium, ruthenium, indium, silver, and gold. Therefore, it is one preferable embodiment that the catalyst is made of a substance containing at least one element selected from the group consisting of platinum, rhodium, palladium, ruthenium, indium, silver and gold. Examples of the substance containing the element include various forms such as a simple metal, a metal oxide, and other compounds (chloride, sulfate, etc.). These substances may be used alone or in combination of two or more. In addition, unlike the packed bed system in which the granular catalyst is filled, the cell space serving as the gas passage is sufficiently secured, and the passage of the gas is hardly hindered. Further, since the catalyst component is supported, heat transfer between the catalysts is good. Since the catalyst is supported on the surface of the plate electrode 41 that generates plasma, in order to react the raw material gas, radicals are generated by plasma generated by barrier discharge, and the catalytic reaction and the plasma reaction are combined to perform the reforming reaction. The temperature can be lowered. As a result, it is possible to obtain effects such as suppression of catalyst deterioration by lowering the reaction temperature, reduction of the amount of catalyst by combining with plasma, and expansion of applications as an inexpensive system by reducing noble metal catalyst.

  The amount of the catalyst supported is preferably 0.05 to 70 [g (catalyst mass) / L (volume of reactor body)], more preferably 0.1 to 40 g / L. If the loading is less than 0.05 g / L, the catalytic action may be difficult to develop. On the other hand, if it exceeds 70 g / L, the production cost of the plasma reactor may increase.

  The catalyst is preferably carried on the surface of the plate electrode 41 in the form of catalyst coated fine particles carried on carrier fine particles. Such a form has an advantage of increasing the reaction efficiency of the raw material gas with respect to the catalyst. As the carrier fine particles, for example, ceramic powder can be used. Although the kind of ceramics is not particularly limited, for example, powders of metal oxides, particularly silica, alumina, titania, zirconia, ceria, zeolite, mordenite, silica alumina, metal silicate, cordierite and the like can be suitably used. These ceramics may be used individually by 1 type, and may be used in combination of 2 or more types. The catalyst coated fine particles can be supported by coating the surface of the flat plate electrode 41.

  The average particle size of the carrier fine particles is preferably 0.01 to 50 μm, and more preferably 0.1 to 20 μm. If the average particle size is less than 0.01 μm, the catalyst may be hardly supported on the surface of the carrier fine particles. If the average particle diameter exceeds 50 μm, the catalyst coated fine particles may be easily peeled off from the flat plate electrode 41.

  The mass ratio of the catalyst to the carrier fine particles is preferably 0.1 to 20% by mass, and more preferably 1 to 10% by mass. If the mass ratio of the catalyst is less than 0.1% by mass, the reforming reaction may hardly proceed. If it exceeds 20% by mass, the catalysts are not uniformly dispersed but easily aggregated with each other, so that it may be difficult to uniformly support the carrier fine particles. Therefore, even if an amount of the catalyst exceeding 20% by mass is added, the catalyst addition effect corresponding to the amount cannot be obtained, and the reforming reaction may not be promoted.

  The catalyst-coated fine particles can be obtained, for example, by impregnating a ceramic powder serving as carrier fine particles with an aqueous solution containing a catalyst component, followed by drying and firing. A dispersion medium (water, etc.) and other additives are added to the catalyst-coated fine particles to prepare a coating liquid (slurry), and the slurry is coated on the surface of the plate electrode 41, whereby the catalyst is applied to the surface of the plate electrode 41. It can be supported.

  In the plasma reactor 100 of the present embodiment, the introduction path 31 is formed along at least a part of the side surface 22 of the reactor main body 21, and the fluid flowing in from the inlet 2 flows along the side surface 22 of the reactor main body 21. It is led to one end 11 of the reactor main body 21 while flowing. As shown in FIGS. 1 and 2, the introduction path 31 is a space surrounded by the heater 35 disposed on the side surface 22 of the reactor main body 21, the introduction path heater 32, and the wall surface of the outer frame body 1. . The introduction path 31 is preferably surrounded entirely by the heater 35 and the introduction path heater 32 (the wall surface of the outer frame 1 does not directly face the introduction path 31). That is, the introduction path 31 is preferably formed by the heater 35 and the introduction path heater 32. As shown in FIGS. 1 and 2, the heater 35 and the introduction path heater 32 are exposed in the introduction path 31 by forming the introduction path 31 with the heater 3 and the introduction path heater 32. Although it is preferable, for example, the introduction path 31 may be surrounded by a cylindrical wall, and the heater 3 and the introduction path heater 32 may be disposed outside the introduction path 31. As shown in FIGS. 1 and 2, when the reactor main body 21 is a rectangular parallelepiped, the introduction path 31 is preferably formed along the entire one surface (side surface) of the rectangular parallelepiped. Thus, since the introduction path 31 is formed along the side surface 22 of the reactor main body 21, heating the gas flowing through the introduction path 31 simultaneously heats the reactor main body 21. In addition, since the reactor main body 21 is also kept warm by the introduction path 31, the heat required for the reforming reaction can be minimized, and a reforming reaction with high thermal efficiency can be performed. Further, since the introduction path 31 is formed along the side surface 22 of the reactor main body 21, the entire plasma reactor 100 can be miniaturized, and the heat radiation can be reduced by the miniaturization. Also in that it can be performed, the plasma reactor 100 of the present embodiment is a plasma reactor with high thermal efficiency.

  Although the magnitude | size of the introduction path 31 is not specifically limited, The width | variety (length in the direction orthogonal to the side surface of a reactor main body) along the side surface of a reactor main body has preferable 1 mm-30 mm, Furthermore, 5 mm-20 mm Is more preferable. When the gap is smaller than 1 mm, the pressure loss is large when the raw material gas flows, and the reforming efficiency may be deteriorated. On the other hand, if the gap is larger than 30 mm, the temperature of the raw material gas is difficult to rise and the energy efficiency may be poor.

  In the plasma reactor 100 of the present embodiment, the reformed gas (gas obtained by reforming the raw material gas) discharged from the other end (outlet side end) 12 of the reactor main body 21 is discharged from the outlet. 3 exits the plasma reactor 100, but between the other end (outlet end) 12 of the reactor body 21 and the outlet 3, as shown in FIGS. It is preferable that a discharge path 34 is formed for circulating the gas. The discharge path 34 is preferably not directly connected to the introduction path 31 (only connected through the flow path 13 of the reactor main body 21). Thereby, it is possible to prevent the source gas and the reformed gas from being mixed in the plasma reactor 100.

  The heater 35 and the introduction path heater 32 are plate-shaped (plate-shaped) heating plates, and both are heated by a heater power source. The heater 35 and the introduction path heater 32 heat the reactor main body 21 and the introduction path 31 when a flat heating plate generates heat. The introduction path 31 is preferably formed so as to be surrounded by these heating plates. The material of the heater 35 and the introduction path heater 32 is preferably an insulating material that saves power and has a high output (temperature increases). The power supply for the heater may be either direct current or alternating current. If direct current is used, it is preferable to use a stabilized DC power supply, and if alternating current, a transformer or a slider is preferably used. It is more preferable to use an AC power supply having no polarity. The reactor main body 21 preferably generates heat in the range of 750 to 950 ° C, and more preferably generates heat in the range of 800 to 900 ° C. If it is lower than 750 ° C., the reforming reaction may be difficult to occur. If it is higher than 950 ° C., cracking of the reactor main body 21 is likely to occur and the life may be shortened.

  In addition, in the plasma reactor 100 of the present embodiment, in addition to the heater 35 and the introduction path heater 32, a reactor body heater for heating the reactor body 21 is provided on the side surface of the reactor body (the heater 35 is It is preferable to be disposed on a side surface that is not disposed. Further, when plasma is generated in the reactor main body 21, the reactor main body 21 is heated by the generation of plasma. Therefore, it can be said that the plasma generating electrode (flat plate electrode 41) is also an apparatus for heating the reactor main body 21.

  In the plasma reactor 100 of the present embodiment, it is preferable that a heat insulating material 33 is disposed between the introduction path heater 32 and the outer frame body 1 (gap). By disposing the heat insulating material 33, the plasma reactor 100 becomes a more efficient plasma reactor. Although it does not specifically limit as the heat insulating material 33, It is preferable to use a fireproof heat insulation brick.

2. Plasma reactor manufacturing method:

  The manufacturing method of the reactor main body 21 is not specifically limited. For example, it can be manufactured by a green sheet lamination method. The green sheet laminating method is a method in which a ceramic green sheet in which a conductive film is embedded is produced, and laminated and sintered.

  The method for producing the ceramic green sheet in which the conductive film is embedded is not particularly limited. For example, first, a ceramic green sheet is produced using a doctor blade method, a calendar method, a printing method, a roll coater, a plating method, or the like. At this time, as a raw material of the ceramic green sheet, it is preferable to use the ceramic powder mentioned as a preferable material of the ceramic dielectric 43. Further, it is preferable to add silicon oxide, calcia, titania, magnesia, zirconia or the like as a sintering aid to the raw material. In addition, a known dispersant, plasticizer, and organic solvent can be added to the raw material of the ceramic green sheet. As a raw material of the ceramic green sheet, it is preferable to use a slurry of the above raw material. The sintering aid is preferably added in an amount of 3 to 10 parts by mass with respect to 100 parts by mass of the ceramic powder.

  Then, a conductive paste is applied on the obtained ceramic green sheet, and another ceramic green sheet is stacked on the ceramic green sheet to which the conductive paste is applied so as to sandwich the conductive paste, thereby forming a flat plate electrode before sintering. Is preferred. As a method for applying the conductor paste, any coating method such as screen printing, calendar roll printing, dipping, vapor deposition, physical vapor deposition, or the like can be used. The conductor paste is preferably prepared by mixing powders of various metals or alloys mentioned as preferred materials for the conductive film with an organic binder and a solvent (such as terpineol).

  And the reactor main body 21 is obtained by laminating | stacking and sintering the obtained flat electrode before sintering through a spacer. The spacer is preferably made of the same raw material as the ceramic green sheet.

  Moreover, as another embodiment of the manufacturing method of the reactor main body 21, the method of producing several flat plate electrodes by the powder press molding method, laminating | stacking them, and sintering and making it a reactor main body can be mentioned. . The powder press molding method is a method of obtaining a sintered body by hot press molding a ceramic dielectric powder. When producing a flat plate electrode, it can be set as a flat plate electrode by hot-pressing in the state which mesh metal and metal foil were embed | buried in ceramic powder, and obtaining a sintered compact. The ceramic dielectric has a function as a dielectric. By using the conductive film disposed inside the ceramic dielectric, the arc discharge is compared with the case where the conductive film is discharged alone. Can be suppressed.

  The outer frame 1, the heater 35, the introduction path heater 32, and the heat insulating material 33 process a predetermined material into a predetermined shape. For example, it is preferable to process the shape as shown in FIGS. Further, when the outer frame body 1 is a metal, an insulator is provided to prevent the outer frame body 1 and the reactor main body 21 from coming into contact when the reactor main body 21 is disposed in the outer frame body 1. It is preferable to interpose. This insulator can be obtained by processing a material such as ceramics into a sheet (plate). As the ceramic, for example, alumina, zirconia, silicon nitride, aluminum nitride, sialon, mullite, silica, cordierite, or the like is preferably used. In particular, it is more preferable to appropriately select the insulating material depending on the application of the plasma reactor. For example, cordierite is preferable if the main point is low heat capacity from the viewpoint of insulation, heat shielding, thermal stress reduction, or catalytic activity. Alumina or the like is preferable if the main point is to be provided, and silicon nitride or the like is preferable if the main point is on heat transfer or reliability as a further structure.

  The obtained reactor body 21, outer frame 1, insulator, heater 35, introduction path heater 32, and heat insulating material 33 are assembled, a pulse power source is connected to the reactor body 21, and the heater 35, The plasma reactor 100 can be obtained by connecting a power source for a heater to the introduction path heater 32.

3. How to use the plasma reactor:
When hydrogen is generated using the plasma reactor of the present invention, the reforming raw material gas is not particularly limited as long as it can generate a hydrogen-containing gas. For example, a hydrocarbon compound (for example, Light hydrocarbons such as methane, propane, butane, heptane, hexane, etc., petroleum hydrocarbons such as isooctane, gasoline, kerosene, light oil, naphtha) and alcohols (for example, methanol, ethanol, n-propanol, 2-propanol, 1 -Butanol) can be used. A mixture thereof can also be used. The reforming method may be any reforming method such as partial reforming using oxygen, steam reforming using water, and autothermal using oxygen and water.

  The plasma reactor of the present invention is small in size, and can be installed in, for example, an automobile, and a part of fuel (fuel added gas) can be introduced to reform the fuel.

  A method for performing the reforming reaction using the plasma reactor 100 of the present embodiment shown in FIGS. 1 and 2 is, for example, as follows.

  The introduction path 31 and the reactor main body 21 are heated in advance by heating the heater 35 and the introduction path heater 32. At this time, the introduction path 31 is preferably set to 100 to 400 ° C. Then, a pulse voltage is applied to the reactor main body 21.

Then, the raw material gas is introduced from the two inlets 2. The source gas may be room temperature. The plasma reactor 100 of this embodiment can be efficiently modified even with such a low-temperature source gas. The flow rate of the raw material gas is appropriately determined depending on the size of the plasma reactor, the intended use, etc. For example, when the reactor main body has a volume of 50 cc, the flow rate is 100-25 × 10 ⁴ cm ³ / min. Preferably there is.

  The source gas that has flowed through the introduction path 31 and has reached the one end 11 of the reactor main body 21 flows into the flow path 13 from the opening of the one end 11. Then, the raw material gas is reformed while flowing through the reactor main body 21, becomes reformed gas, and goes out of the reactor main body 21 from the other end 12 of the reactor main body 21. The reformed gas that has exited from the other end 12 of the reactor main body 21 passes through the discharge path 34 and exits from the plasma reactor 100 through the outlet 3.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

Example 1
A plasma reactor as shown in FIGS. 1 and 2 was produced. Using a 93% alumina (Al ₂ O ₃ ) raw material, a molding aid, a plasticizer, and the like were added, and an alumina tape having a thickness after firing of 0.25 mm was produced. From the tape obtained, an alumina flat plate having a width of 45 mm and a length of 50 mm was used as a basic electrode, and a conductor film having a width of 38 mm, a length of 45 mm and a thickness of 10 μm was printed with a tungsten paste to produce a laminated integrated flat plate electrode. The same tape material as the printed alumina tape was joined under heat and pressure to obtain an alumina flat plate electrode having a thickness of 0.5 mm.

  Twelve alumina tapes having a thickness of 0.25 mm were laminated to produce a spacer. And the laminated body in which discharge space (flow path 13) 1.0mm (distance between flat plate electrodes) was formed by laminating | stacking an alumina flat plate electrode on both sides of the said spacer, and heat-pressing joining was produced. The obtained laminate was fired at 1500 ° C. to obtain a reactor main body.

The outer frame and the piping to be connected were made of stainless steel. Moreover, an alumina (Al ₂ O ₃ ) plate was used as a plate-like insulator disposed inside the outer frame. Moreover, a flat plate heater was used as the heater and the introduction path heater. As the heat insulating material, a fireproof heat insulating brick processed into a predetermined shape was used.

  The obtained reactor main body, outer frame, insulator, heater, introduction path heater, and heat insulating material were assembled as in the plasma reactor shown in FIGS. 1 and 2 to obtain a plasma reactor. The plasma reactor was connected to a pulse power source for generating plasma, a power source for a heater, and piping. As the pulse power source, a high voltage pulse power source (manufactured by NGK Corporation) using an electrostatic induction type (SI) thyristor as a switching element was used. An AC power source was used as the power source for the heater.

  Using the obtained plasma reactor, a reforming test was conducted by the following method. The results are shown in Table 1.

(Modification test)
A hydrocarbon reforming test is performed using a plasma reactor. As the hydrocarbon, using isooctane _{(i-C 8 H 18)} . The reforming method is a partial oxidation reaction of isooctane. Since isooctane is a liquid at room temperature, the gasified in advance is allowed to flow into the plasma reactor. When vaporizing isooctane, the gas to be introduced into the reactor (nitrogen gas containing 8000 ppm of oxygen) is heated to 290 ° C., and it is specified using a high-pressure microfeeder (Furue Science Co., Ltd., JP-H type). An amount of isooctane (2000 ppm based on the whole raw material gas) is injected. Therefore, the source gas flowing into the plasma reactor is N ₂ gas containing 2000 ppm isooctane and 8000 ppm oxygen. The space velocity (SV) when the source gas is introduced into the plasma reactor is 100,000 h ⁻¹ with respect to the space of the flow path of the reactor main body. The temperature when the source gas flows in the introduction path is 150 ° C., and the temperature when the source gas flows in the reactor body is 450 ° C.

Gas chromatography (GC, GC3200, GC3200, equipped with TCD (thermal conductivity detector) for the amount of hydrogen (H ₂ ) in the reformed gas that flows into the plasma reactor and flows out of the source gas, and argon as the carrier gas Gas use) to calculate the hydrogen production rate. In addition, the amount of methane (CH ₄ ) and ethane (C ₂ H ₆ ) in the outflowing reformed gas is measured using helium gas as the GC carrier gas. Methane and ethane correspond to by-products. In these measurements, a mixed standard gas (hydrogen, methane, ethane) with a known concentration is used. In addition, the conditions of the pulse power source for generating plasma are a repetition period of 3 kHz, and a peak voltage of 4.5 kV is applied between the electrodes. The hydrogen yield is calculated using the formula “hydrogen yield (mol%) = hydrogen generation amount (mol) / [isooctane amount in source gas (mol) × 9]”.

(Example 2)
A plasma reactor was produced in the same manner as in Example 1 except that the catalyst was supported on the reactor body. The method for supporting the catalyst on the reactor main body is as follows. A nickel nitrate (Ni (NO ₃ ) ₂ ) solution is impregnated with finely divided alumina (specific surface area 107 m ² / g), dried at 120 ° C., fired at 550 ° C. for 3 hours in the atmosphere, and nickel (Ni) against alumina. Ni / alumina powder containing 20% by mass was obtained. Water was added thereto, and then adjusted to pH 4 with a nitric acid solution to obtain a slurry. The reactor main body was immersed in the slurry, dried at 120 ° C., and then fired at 550 ° C. for 1 hour in a nitrogen atmosphere to prepare a reactor main body carrying a catalyst. At this time, the amount of Ni supported on the reactor main body was 50 g / L. A modification test was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
A reactor main body was prepared in the same manner as in Example 1, and this reactor main body was used as a plasma reactor. A modification test was performed in the same manner as in Example 1. The results are shown in Table 1. When performing a reforming test, connect a pulse power supply to the reactor main body, let the raw material gas flow directly from the opening at one end of the reactor main body, and analyze the reformed gas flowing out from the other end did.

(Comparative Example 2)
A plasma reactor was produced in the same manner as in Comparative Example 1 except that the catalyst was supported on the reactor body. The method of loading the catalyst on the reactor main body was the same as in Example 2. A modification test was conducted in the same manner as in Comparative Example 1. The results are shown in Table 1.

  From Table 1, comparing the plasma reactors of Examples 1 and 2 with the plasma reactors of Comparative Examples 1 and 2, the plasma reactors of Examples 1 and 2 have a higher hydrogen production rate and are by-products. It can be seen that the production of methane and ethane is suppressed. Therefore, when the source gas is at a low temperature, it is more efficient to introduce the source gas into the reactor body while heating the source gas in the plasma reactor than to introduce the source gas directly into the reactor body. It can be seen that it can contribute to the reforming reaction and a high hydrogen production rate.

  Moreover, it turns out that the plasma reactor of Example 2 which combined plasma discharge and the catalyst has a higher hydrogen production rate than the plasma reactor of Example 1 which made only plasma discharge. In addition, it can be seen that the amount of generated methane and ethane, which are by-products, is smaller in the plasma reactor of Example 2 than in the plasma reactor of Example 1. Even in the case of the plasma reactors of Comparative Examples 1 and 2, it can be seen that the hydrogen generation rate is higher when the plasma discharge and the catalyst are combined, and methane and ethane, which are by-products, are also reduced. From these results, it was found that hydrogen can be efficiently generated from isooctane by combining plasma discharge and a catalyst.

  It can be suitably used as an apparatus for reforming a source gas to generate hydrogen.

1: Outer frame, 2: Inlet, 3: Outlet, 11: One end (inlet side end), 12: The other end (outlet side end), 13: Channel, 14: Partition , 21: reactor main body, 22 and 22a: side surface of reactor main body, 31: introduction path, 32: introduction path heater, 33: heat insulating material, 34: discharge path, 35: heater, 41: plate electrode, 42 : Conductive film, 43: ceramic dielectric, 44: spacer, 45: terminal assembly, 100: plasma reactor.

Claims (7)

An outer frame in which an inflow port that is an inlet for allowing fluid to flow into the inside and an outflow port that is an outlet for allowing fluid to flow out to the outside are formed;
A partition wall defining a flow path penetrating from one end portion into which the fluid flows to the other end portion from which the fluid flows out, a part of the partition wall being a plasma generating electrode, and the fluid flowing in from the inflow port Flows into the flow path from the one end, passes through the flow path, flows out from the other end, and further flows out from the outflow port. A cylindrical reactor body disposed; and
It is formed along at least a part of the side surface of the reactor body, and the fluid flowing in from the inlet is guided to the one end portion of the reactor body while flowing along the side surface of the reactor body. Introduction path,
A plasma reactor comprising: a heater disposed in a portion along the introduction path in a side surface of the reactor main body; and an introduction path heater disposed in the introduction path.   The plasma reactor according to claim 1, wherein the heater and the introduction path heater are plate-shaped heating plates, and the introduction path is surrounded by the heating plate.   A plasma generation power source for applying a voltage to the plasma generation electrode is provided, and plasma can be generated in the reactor body by applying a pulse voltage to the plasma generation electrode from the plasma generation power source. 2. The plasma reactor according to 2.   The plasma reactor according to claim 1, wherein a catalyst is supported on the reactor main body.   The catalyst is at least one selected from the group consisting of noble metals, aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, and barium. The plasma reactor according to claim 4, comprising a substance containing an element.   The plasma reactor according to claim 4, wherein the catalyst is made of a substance containing at least one element selected from the group consisting of platinum, rhodium, palladium, ruthenium, indium, silver and gold.   The plasma reactor according to any one of claims 3 to 6, wherein the plasma generation power source is a high voltage pulse power source using an electrostatic induction thyristor.

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