JP2010235348A - Self-heated oxidation reforming apparatus and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive self-heated oxidation reforming apparatus which can improve reforming efficiency and has a simple structure, and a fuel cell system capable of enhancing power generation efficiency. <P>SOLUTION: The self-heated oxidation reforming apparatus includes: a reaction tube having a reforming layer forming a reformed gas consisting essentially of hydrogen by the reforming reaction of a mixture of a raw material with water and an oxidation heat generating layer generating heat by the oxidation of the raw material or a part of the reformed gas; an oxidizing gas supply means for supplying an oxidizing gas to the oxidation heat generating layer; and a heating means for heating the inside of the reaction tube by bringing a high temperature combustion gas into contact with an outer periphery of the reaction tube. The reaction tube has an end closed and a double tube structure where an inner tube and an outer tube communicate with each other in the closed end, the oxidation heat generating layer is positioned in the inner tube, the reforming layer is positioned in a space part between the outer tube and the inner tube of the reaction tube, and the self-heated oxidation reforming apparatus is further provided with a mixture supply flow path for supplying the mixture into the inner tube of the reaction tube and a reformed gas discharge flow path for discharging the reformed gas from the space part. The fuel cell system is provided with the self-heated oxidation reforming apparatus. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reformer for producing a reformed gas mainly composed of hydrogen by a reforming reaction by bringing a mixture of a hydrocarbon or an aliphatic alcohol and steam into contact with a reforming catalyst, and in particular, The present invention relates to an oxidation autothermal reforming apparatus that can utilize oxidation heat in the apparatus for a reforming reaction. The present invention also relates to a fuel cell system including the oxidation autothermal reformer.

  Conventionally, a catalyst comprising a reforming catalyst and an oxidation catalyst is used as a reforming device for producing a reformed gas mainly composed of hydrogen by bringing a mixture of hydrocarbon or aliphatic alcohol and water vapor into contact with the reforming catalyst. By supplying hydrocarbon or aliphatic alcohol, water vapor, and oxygen to the layer, a part of the hydrocarbon or aliphatic alcohol is oxidatively exothermic so that the heat necessary for the reforming reaction, which is an endothermic reaction, is supplied. An oxidation self-heating type reformer is known (for example, see Patent Document 1).

  Moreover, in the oxidation autothermal reformer as described above, the temperature distribution in the catalyst layer is made gentle so that raw material slip occurs and the hydrogen concentration is low due to chemical equilibrium (relatively high methane concentration). As a reformer capable of preventing the generation of quality gas, a reforming catalyst and an oxidation catalyst are filled in a reforming pipe having a double pipe structure consisting of an inner pipe and an outer pipe, and a hydrocarbon or an aliphatic alcohol, There is known an oxidation autothermal reformer in which water vapor and oxygen are allowed to flow in a U-turn gas flow from an inner pipe to an outer pipe (see, for example, Patent Document 2).

  However, in the oxidation autothermal reformer using the above-described double-tube structure reforming tube, heat generated by the oxidation reaction at the reforming tube inlet side is transmitted to the catalyst layer on the outside (reforming tube outlet side). Although the catalyst layer can suppress the temperature distribution of the catalyst layer, a mixture of hydrocarbon or aliphatic alcohol, water vapor, and oxygen is supplied to the catalyst layer. It has been difficult to use the catalyst as a reforming catalyst. In addition, since a part of the hydrocarbon or aliphatic alcohol supplied as the raw material for the reforming reaction is burned to obtain the amount of heat necessary for the reforming, the reforming efficiency (hydrogen generation amount / raw material supply amount) decreases. There was a problem that.

  In contrast, in a solid oxide fuel cell module comprising a solid oxide fuel cell (SOFC) and a reformer, the exhaust heat generated from the solid oxide fuel cell is used as a reforming reaction of the reformer. Developed a method to make the solid oxide fuel cell module self-sustained by using a wasteless amount of heat required for the reforming reaction to compensate for the amount of heat by advancing the oxidation exothermic reaction in the reformer. (For example, see Patent Document 3).

  The above solid oxide fuel cell module has a triple tube structure as a reformer so that a catalyst having poor oxidation resistance can be used for the reforming reaction in the reformer. The cylindrical modified layer (inner modified layer and outer modified layer) and the cylindrical oxidation heating layer located downstream of the modified layer are formed from the radially inner side to the inner modified layer. In addition, a reforming apparatus is used in which an oxidation exothermic layer and an outer reforming layer are arranged in this order, and an oxidizing gas introduction pipe for directly supplying an oxidizing gas to the oxidizing exothermic layer is provided.

JP 2001-192201 A JP 2003-306306 A JP 2007-227237 A

  Here, in the above-described reformer for a solid oxide fuel cell module, the catalyst layer is separated into a reforming layer containing a reforming catalyst and an oxidation heating layer containing an oxidation catalyst, and only the oxidation heating layer is oxidized. Since a reactive gas is supplied, a catalyst with inferior oxidation resistance can be used for the reforming layer, but a triple tube structure is adopted to enhance the heat transfer of the heat generated in the oxidation heating layer. Therefore, there is a problem that the structure is complicated, it is difficult to reduce the size, and the manufacturing cost is high.

  In addition, the composition of the reformed gas is affected by the temperature at the outlet of the catalyst layer in terms of chemical equilibrium, and the hydrogen content of the reformed gas increases as the temperature at the outlet of the catalyst layer increases. In the module reforming apparatus, the inner reforming layer, the outer reforming layer, and the oxidation exothermic layer are arranged in the order of the inner reforming layer, the oxidizing exothermic layer, and the outer reforming layer from the inner side in the radial direction. The gas is exhausted through the central oxidation heating layer. Therefore, in the above reformer that advances the oxidation exothermic reaction only when the amount of heat required for the reforming reaction is insufficient, most of the exhaust heat generated from the solid oxide fuel cell is reformed in the outer reforming layer. There was a problem that it was used for the reaction and was not sufficiently transmitted to the oxidation exothermic layer and the inner modified layer. Therefore, in the reformer, the reformed gas temperature is prevented from lowering at the catalyst layer outlet, that is, the oxidation exothermic layer outlet, and the hydrogen content of the reformed gas is prevented from being lowered. In order to supplement the amount of heat necessary for the reforming reaction, there was room for improvement in that the oxidation exothermic reaction must eventually proceed in the oxidation exothermic layer.

  Therefore, it can be manufactured at low cost, and the amount of raw materials and reformed gas used for the oxidation exothermic reaction in the oxidation exothermic layer is further reduced by efficiently using the heat supplied from the outside. There has been a demand for an oxidation autothermal reformer having a simple structure capable of (improving reforming efficiency).

In general, the fuel utilization rate (amount of reformed gas used for power generation / amount of reformed gas supplied) of a fuel cell such as a solid oxide fuel cell (SOFC) is about 70 to 85%. Thus, off-gas containing unburned gas (H ₂ , CO, CH ₄ ) is surely discharged from the fuel cell during power generation. Therefore, it is possible to increase power generation efficiency (power generation amount / reformed gas supply amount) by effectively using heat generated from the fuel cell itself during power generation and combustion heat generated by burning unburned gas in off-gas. Fuel cell systems have been demanded.

  An object of the present invention is to advantageously solve the above problems, and the oxidation autothermal reformer of the present invention comprises at least one raw material selected from the group consisting of hydrocarbons and aliphatic alcohols. A reforming layer that generates a reformed gas mainly composed of hydrogen by a reforming reaction of a mixture with water vapor, and an oxidation exothermic layer that generates heat by oxidizing part of the raw material or the reformed gas. An oxidation self-heating type comprising a reaction tube, an oxidizing gas supply means for supplying an oxidizing gas to the oxidation heat generating layer, and a heating means for heating the inside of the reaction tube by bringing a high-temperature combustion gas into contact with the outer periphery of the reaction tube The reaction tube has a double tube structure in which one end is closed and an inner tube and an outer tube communicate with each other at the closed end, and the oxidation exothermic layer includes: At least partially filled with an oxidation catalyst, The reforming layer is located in a gap between the outer tube and the inner tube, and the reforming layer is at least partially filled with a reforming catalyst, and is located in the inner tube, and the reaction tube includes the reaction tube. It further comprises a mixture supply channel for supplying the mixture into the inner pipe, and a reformed gas discharge channel for discharging the reformed gas from the gap. As described above, when the reforming layer is disposed on the upstream side of the oxidation heat generating layer and the oxidizing gas supply means for supplying the oxidizing gas to the oxidation heat generating layer is provided, the oxidizing gas is supplied to the reforming catalyst of the reforming layer. Since there is no direct contact, a reforming catalyst having poor oxidation resistance can be used in the reforming layer. Further, if the reaction tube has a double tube structure, the apparatus can be reduced in size as compared with a triple tube structure, and the apparatus can be manufactured at low cost. Furthermore, if a reforming layer is disposed radially inside the reaction tube and an oxidation heat generation layer is disposed radially outside, and a heating means for heating the inside of the reaction tube is provided, the oxidation heat generation layer is efficiently heated to generate oxidation heat. A high-temperature reformed gas with a high hydrogen content can be obtained at the layer outlet, and the reforming efficiency can also be improved by utilizing the heat supplied from the outside for the reforming reaction in the reforming layer. In the present invention, hydrogen as a main component means that 50% by volume or more of hydrogen is a dry base excluding moisture in the reformed gas.

  Here, the oxidation autothermal reforming apparatus of the present invention includes a flow path section having the mixture supply flow path and the reformed gas discharge flow path at the other end opposite to the one end of the reaction tube. At the other end, the mixture supply channel is connected to the inner pipe, and the reformed gas discharge channel is connected to the gap, and the reformed gas discharge is connected to the channel unit. It is preferable that the flow path is located closer to the connection part between the outer tube and the flow path part than the mixture supply flow path. The inner tube and the outer tube of the reaction tube communicate with each other at the closed end, and the reformed gas generated by the reforming reaction in the reforming layer is discharged through the gap, and the closed tube is closed. When the mixture supply channel and the reformed gas discharge channel are provided at the end (the other end) opposite to the end, the introduction of the raw material into the reformed layer and the discharge of the reformed gas from the gap This is because it is not necessary to provide complicated piping, and the apparatus can be easily manufactured.

  In addition, the oxidation autothermal reforming apparatus of the present invention preferably has a plurality of the reaction tubes, and the mixture supply channel and the reformed gas discharge channel of each reaction tube are respectively common. This is because the reforming apparatus can be made compact and the degree of freedom in arrangement of the apparatus is increased. Further, the contact area between the reaction tube and the high-temperature combustion gas is increased, and heat can be sufficiently supplied to the reforming layer. Further, when the reformer is installed and used inside a fuel cell module, for example, it can be arranged close to the fuel cell by taking advantage of the degree of freedom of arrangement, and the radiant heat from the fuel cell can be reacted in a plurality of ways. This is because it can be used effectively in the pipe and can contribute to the improvement of the heat utilization efficiency of the fuel cell module.

  Furthermore, in the oxidation autothermal reforming apparatus of the present invention, the mixture inlet to the mixture supply channel and the outlet of the reformed gas from the reformed gas discharge channel each have the reaction. It is preferable that it is located on the opposite side across the tube. This is because, for example, even in an oxidation autothermal reformer having a plurality of reaction tubes, the distance from the inlet portion to the outlet portion is equal for each reaction tube. That is, the distances through which the fluid flows can be made substantially equal for each reaction tube, the mixture can be supplied and distributed almost uniformly to all reaction tubes, and the reforming reaction can proceed almost uniformly. is there.

  Further, the oxidation self-heat reforming apparatus of the present invention includes the flow path section, and the heating means causes the high-temperature combustion gas to flow in the direction from the one end to the other end to pass through the reaction tube. It is preferable to heat. When the reformed gas is used as fuel for a fuel cell that operates at a high temperature such as a solid oxide fuel cell, the reformed gas is preferably discharged from the reformer at a high temperature (for example, 700 to 800 ° C.). This is because if the reformed gas discharge channel is located on the side where the combustion gas is supplied, it is possible to prevent the temperature of the reformed gas from decreasing in the reformed gas discharge channel. In addition, since the mixture supply flow path is located downstream of the reformed gas discharge flow path with respect to the flow direction of the high-temperature combustion gas, the temperature of the mixture supply flow path is unlikely to increase. This is because the occurrence of coking can be prevented.

  Furthermore, in the oxidation autothermal reforming apparatus of the present invention, the oxidizing gas supply means is disposed inside the inner tube and extends from the reforming layer of the reaction tube to the one end side. A supply pipe is preferred. This is because if the oxidizing gas is supplied from the oxidizing gas supply pipe disposed inside the inner pipe, the oxidizing gas necessary for the oxidation reaction in the oxidation heat generating layer can be supplied with a simple configuration. In the oxidation autothermal reformer of the present invention, the oxidizing gas supply pipe extends to the closed end side so that a catalyst having poor oxidation resistance can be used as the reforming catalyst. There must be. That is, the position where the oxidizing gas is ejected from the oxidizing gas supply pipe must be located on the downstream side (oxidation exothermic layer side) of the reforming layer.

  In the oxidation autothermal reforming apparatus of the present invention, it is preferable that the reforming catalyst contains Ru. In the oxidation self-heat reforming apparatus of the present invention, the oxidation exothermic layer is located on the rear side of the reforming layer, so that the Ru-based catalyst has a long activity and high activity and is difficult to cause coking although it has poor oxidation resistance. It is because it can be used.

  Furthermore, in the oxidation autothermal reformer of the present invention, the raw material is preferably at least one selected from the group consisting of light oil, kerosene, gasoline and naphtha. This is because these raw materials have a large carbon number, are easy to handle and store, and can be obtained at low cost.

  Further, the fuel cell system of the present invention includes the above-described oxidation autothermal reformer, a fuel cell that uses the reformed gas discharged from the oxidation autothermal reformer as fuel, and an exhaust from the fuel cell. And a combustion device for generating off-gas combustion gas by burning off-gas generated, wherein the high-temperature combustion gas is the off-gas combustion gas. As described above, if the off-gas combustion gas generated when the off-gas discharged from the fuel cell is burned is used as a high-temperature combustion gas for the reforming reaction, the power generation efficiency can be increased.

  The fuel cell system of the present invention includes the above-described oxidation autothermal reformer, a fuel cell that uses the reformed gas discharged from the oxidation autothermal reformer as fuel, and an exhaust from the fuel cell. A first combustion device that burns off-gas generated to produce off-gas combustion gas, and a second combustion device that burns hydrocarbon or aliphatic alcohol to generate burner combustion gas, wherein the high-temperature combustion gas is the off-gas It is a combustion gas and / or the burner combustion gas. Thus, if the oxidation autothermal reformer described above is used, it is possible to save space and reduce the cost of the fuel cell system. Further, by providing the second combustion device that burns hydrocarbons or aliphatic alcohols to generate burner combustion gas, the reaction tube can be heated without being affected by the operating state of the fuel cell. In the present invention, the first combustion device and the second combustion device may be separate combustion devices, or a single combustion device that can burn both off-gas and hydrocarbon or aliphatic alcohol. One combustion device may be used.

  Here, in the fuel cell system of the present invention, the fuel cell is preferably a solid oxide fuel cell. This is because, when a solid oxide fuel cell is used as the fuel cell, the radiant heat from the solid oxide fuel cell that generates heat can also be used for heating the oxidation exothermic layer and the reforming reaction in the reforming layer.

  According to the oxidation autothermal reforming apparatus of the present invention, it is possible to produce at a low cost and improve the reforming efficiency by efficiently using the heat supplied from the outside. An oxidation autothermal reformer having a simple structure can be provided. Moreover, according to the fuel cell system of the present invention, it is possible to provide a fuel cell system capable of increasing the power generation efficiency.

It is a perspective view which shows an example of the oxidation autothermal reforming apparatus of this invention. It is explanatory drawing which shows the oxidation autothermal reformer shown in FIG. 1 in a cross section.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an example of the oxidation autothermal reforming apparatus of the present invention, and FIG. 2 is an explanatory view showing a cross section of the oxidation autothermal reforming apparatus 100 shown in FIG. . The oxidation autothermal reformer 100 shown in FIGS. 1 and 2 can be used, for example, for the production of reformed gas as fuel for a fuel cell. In this embodiment, the oxidation autothermal reformer is used. 100 is used in a part of a fuel cell system using a solid oxide fuel cell.

  Here, as shown in FIGS. 1 and 2, the oxidation autothermal reforming apparatus 100 includes three reaction tubes 110 and a manifold 120 as a flow path provided at the lower portion of the reaction tubes 110. It is used to generate a reformed gas mainly composed of hydrogen by reforming a mixture of raw materials and steam. The reaction tube 110 of the oxidation autothermal reformer 100 is heated by combustion gas discharged from a combustion device (not shown) as heating means and radiant heat from the solid oxide fuel cell. In the oxidation autothermal reforming apparatus of the present invention, the number of reaction tubes can be any number, and the shape of the manifold and the arrangement of the reaction tubes on the manifold can also be any shape. . Specifically, the arrangement of the reaction tubes on the manifold may be straight, L-shaped, V-shaped, U-shaped, corrugated, circular, triangular, quadrangular, pentagonal, hexagonal, other polygons, zigzag, etc. it can. Alternatively, the reaction tubes may be arranged in a plurality of rows on the manifold. Furthermore, the planar shape of the manifold (the shape seen from the reaction tube side) can be an appropriate shape depending on the arrangement of the reaction tubes, for example, square, rectangular, triangular, circular, L-shaped, V-shaped. , U-shape, zigzag shape, etc. The size of the reaction tube can be determined according to the required catalyst amount and the surface area required for heating using the combustion gas.

  As shown in FIG. 2, the reaction tube 110 of the oxidation autothermal reformer 100 has a double tube structure including an outer tube 111 having an upper end closed and an inner tube 112. The inner tube 112 has an inverted convex shape protruding downward. Further, an oxidizing gas supply pipe 118 for supplying air or oxygen as an oxidizing gas is provided inside the inner pipe 112 of the reaction pipe 110. An oxidation heat generation layer 116 composed of an oxidation catalyst layer 114 made of an oxidation catalyst and a heat transfer particle layer 115 made of heat transfer particles is provided in a gap between the outer tube 111 and the inner tube 112. In the inner pipe 112, a reforming layer 113 made of a reforming catalyst is provided. The reforming catalyst, the oxidation catalyst, and the heat transfer particles are supported by a mesh 117 provided below the outer tube 111 and the inner tube 112. The mesh 117 is formed by the reforming catalyst, the oxidation catalyst, and the heat transfer particles. Is not allowed to pass through, but the raw material, water vapor and reformed gas are allowed to pass through. Further, the double pipe structure including the outer pipe 111 and the inner pipe 112 is formed by welding and fixing two pipes having different diameters to a manifold 120 described in detail later.

  Here, as the reforming catalyst constituting the reforming layer 113, a conventionally used steam reforming catalyst can be used. For example, Ru, Ni, W, Co, Rh, Pt and the like are made of alumina, silica, A catalyst supported on a carrier such as zirconia can be filled into the inner tube 112 to form the modified layer 113.

  Further, as the oxidation catalyst constituting a part of the oxidation heat generation layer 116, an oxidation catalyst or the like in which Pt, Pd or the like that hardly deteriorates at a high temperature is supported on the carrier can be used, and the addition amount of the oxidation catalyst is changed. It is preferable to make the oxidation self-heating reformer 100 more than the amount that is necessary for supplementing the endotherm due to the quality and allowing the oxidizing self-heating reformer 100 to be thermally self-reacted and that allows the oxidizing gas to be completely reacted. Furthermore, as the heat transfer particles, particles capable of transferring heat generated by an oxidation reaction using an oxidation catalyst, such as SiC particles, can be used. In the oxidation heat generation layer 116 of the oxidation self-heat reforming apparatus 100 shown in FIG. 2, the oxidation heat generation layer is formed of the oxidation catalyst layer 114 and the heat transfer particle layer 115 by filling the heat transfer particles and then the oxidation catalyst. 116 is formed, but the oxidation exothermic layer of the oxidation autothermal reforming apparatus of the present invention is not limited to this. Specifically, the oxidation exothermic layer may be formed by (1) filling a gap between the outer tube and the inner tube with a mixture of the above-described oxidation catalyst and a reforming catalyst supporting Ni, Rh, or the like. (2) The mixture of the oxidation catalyst and the heat transfer particles may be filled in the gap between the outer tube and the inner tube, and (3) the oxidation catalyst, the reforming catalyst, and the heat transfer particles. May be formed by filling the gap between the outer tube and the inner tube.

  The oxidizing gas supply pipe 118 is not particularly limited as long as it can supply the oxidizing gas used for the oxidation reaction to the oxidation catalyst of the oxidation heat generation layer 116, but the reforming catalyst of the reforming layer 113 is deteriorated by the oxidizing gas. In order to avoid this, it is preferable to provide an outlet for oxidizing gas on the rear side of the modified layer 113. In this oxidation self-heating reformer 100, the oxidizing gas supply pipe 118 has a length that protrudes upward from the upper end of the reforming layer 113, and an oxidizing gas jet is ejected from the leading end. Mouth is provided.

  A manifold 120 provided at the lower portion of the reaction tube 110 includes a reformed gas discharge channel 121 for discharging the reformed gas from a gap between the outer tube 111 and the inner tube 112 of the reaction tube 110, and a reaction tube. 110, a mixture supply channel 122 for supplying a mixture of the raw material and water vapor to the inner pipe 112, and an oxidizing gas supply flow for supplying an oxidizing gas to the oxidation heating layer 116 via the oxidizing gas supply pipe 118. Road 123. As shown in FIG. 2, the reformed gas discharge channel 121, the mixture supply channel 122, and the oxidizing gas supply channel 123 of the manifold 120 are channels common to the three reaction tubes 110. Yes. The reformed gas discharge channel 121 communicates with a gap between the outer tube 111 and the inner tube 112 of the reaction tube 110, and the mixture supply channel 122 communicates with the inner tube 112. The gas supply passage 123 communicates with the oxidizing gas supply pipe 118.

  In addition, the manifold 120 has a structure in which the reformed gas discharge channel 121, the mixture supply channel 122, and the oxidizing gas supply channel 123 are integrally laminated in order from the upper side. The distance to the connecting portion 124 between 111 and the manifold 120 is the closest to the reformed gas discharge channel 121, the closest to the mixture supply channel 122, and the farthest to the oxidizing gas supply channel 123. The distance to the connecting portion 124 is compared, for example, by comparing the distance from the center in the height direction (see points A, B, and C in FIG. 2) at the same position in the vertical direction of the manifold 120. Can be done.

  Further, in the manifold 120, an inlet portion through which the mixture is supplied into the mixture supply passage 122 and an outlet portion through which the reformed gas is discharged from the reformed gas discharge passage 121 are sandwiched between the manifold 120 and the reaction tube 110. Are located on opposite sides of each other. In this way, the distribution of the mixture to each reaction tube 110 can be made substantially uniform.

  In the manifold 120, the inlet portion where the oxidizing gas is supplied into the oxidizing gas supply passage 123 is also opposite to the outlet portion of the reformed gas discharge passage 121, that is, the inlet portion of the mixture supply passage 122. Located on the same side as This is preferable from the viewpoint that the distribution of the oxidizing gas to each reaction tube 110 can be made uniform.

  A known combustion apparatus can be used as a combustion apparatus (not shown) that generates combustion gas for heating the reaction tube 110. The high-temperature (500 ° C. or higher, preferably 500 ° C. or higher and 1000 ° C. or lower) combustion gas discharged from this combustion apparatus is blown from the upper side of the reaction tube 110 to the lower side, and the oxidation heat generation layer 116 exits It is used to supply heat for maintaining the temperature of the reformed gas at a high temperature and heat necessary for the reforming reaction in the reforming layer 113 in the reaction tube 110. Examples of the combustion apparatus that burns when generating the combustion gas include hydrocarbons, aliphatic alcohols, and off-gas discharged from the fuel cell. From the viewpoint of improving power generation efficiency, the operation of the fuel cell is exemplified. It is sometimes preferable to use off-gas and use hydrocarbons or aliphatic alcohols only when the fuel cell is started or stopped.

  As a raw material supplied to the oxidation autothermal reforming apparatus 100 described above, at least one raw material selected from the group consisting of hydrocarbons and aliphatic alcohols can be used. The hydrocarbon is not limited, and gas such as methane, ethane, propane, and butane, liquid fuel such as light oil, gasoline, naphtha, and kerosene can be used, and aliphatic alcohol includes methanol, ethanol, and the like. Can be used. Of these, hydrocarbons having a large carbon number, that is, light oil, gasoline, naphtha, and kerosene are preferable, and kerosene is particularly preferable. Further, the water vapor mixed with the raw material can be obtained by evaporating water using a heat exchanger or the like. And these raw materials and water vapor | steam can be supplied to the oxidation autothermal reforming apparatus 100, after mixing with the mixer which is not shown in figure.

  In the oxidation autothermal reformer 100, hydrogen is mainly produced by reforming the mixture of the raw material and water vapor supplied through the mixture supply channel 122 in the reforming layer 113 at a temperature of 400 to 800 ° C., for example. A reformed gas as a component is produced. Specifically, as shown in FIG. 2, the mixture supplied to the reaction tube 110 is reformed by passing through the reforming layer 113 and then folded at the closed end of the upper portion of the reaction tube 110, and then the outer tube. 111 enters the gap between the inner pipe 112 and the oxidation exothermic layer 116 through the down flow and is discharged from the reformed gas discharge passage 121. Here, the amount of heat necessary for the reforming reaction in the reforming layer 113 can be supplied from the outside by the above-described combustion gas or the like, but when the amount of heat is insufficient, such as when the fuel cell is started or when a sudden load change occurs, It is also possible to use heat obtained by supplying an oxidizing gas to the oxidation heat generating layer 116 and oxidizing part of the reformed gas or raw material generated by reforming the mixture.

  The reformed gas generated by the oxidation autothermal reformer 100 is supplied to a normal solid oxide fuel cell in which a plurality of cells are stacked and used as fuel. Here, since the solid oxide fuel cell is operated at a high temperature of 700 to 800 ° C., the radiant heat from the solid oxide fuel cell also reacts if the oxidation autothermal reformer 100 is disposed at an appropriate position. It can be used to heat the tube 110. Further, as described above, the off-gas discharged from the solid oxide fuel cell can be used for generating combustion gas in the combustion apparatus.

  According to the oxidation autothermal reforming apparatus 100 as described above, the oxidation heat generation layer 116 in the reaction tube 110 is located on the surface side of the reaction tube 110, so that the heat supplied from the outside is efficiently used. In addition, a high-temperature reformed gas having a high hydrogen content can be discharged. Also, heat is supplied to the reforming layer 113 of the reaction tube 110 using the combustion gas, and only when the amount of heat necessary for the reforming reaction is insufficient, such as when the fuel cell is started or when a sudden load change occurs. Since it is sufficient to oxidize the raw material and the reformed gas in the oxidation heat generation layer 116, it is not always necessary to supply the oxidizing gas, and the reforming efficiency can be improved. Furthermore, since the reaction tube 110 has a double tube structure, the oxidation autothermal reformer 100 can be easily manufactured at low cost.

  Further, according to the fuel cell system including the oxidation autothermal reformer 100 as described above, the off-gas is burned and heat is supplied to the oxidation autothermal reformer, so that power generation efficiency is improved. Can do.

  Note that the oxidation autothermal reforming apparatus of the present invention is not limited to the above embodiment, and for example, the oxidizing gas may be supplied from the upper side of the reaction tube. Moreover, you may make it supply oxidizing gas with multiple piping with respect to one reaction tube. Furthermore, you may make it supply oxidizing gas using piping inserted from the side surface of the reaction tube.

100 oxidation autothermal reformer 110 reaction tube 111 outer tube 112 inner tube 113 reformed layer 114 oxidation catalyst layer 115 heat transfer particle layer 116 oxidation exothermic layer 117 mesh 118 oxidizing gas supply tube 120 manifold 121 reformed gas discharge flow Channel 122 Mixture supply channel 123 Oxidizing gas supply channel 124 Connection

Claims (11)

A reforming layer that generates a reformed gas mainly composed of hydrogen by a reforming reaction of a mixture of at least one raw material selected from the group consisting of hydrocarbons and aliphatic alcohols and steam; and the raw material or the reforming A reaction tube having an oxidation exothermic layer that oxidizes part of the gas to generate heat;
An oxidizing gas supply means for supplying an oxidizing gas to the oxidation heat generating layer;
Heating means for heating the inside of the reaction tube by bringing a high-temperature combustion gas into contact with the outer periphery of the reaction tube;
An oxidation autothermal reformer comprising:
The reaction tube has a double tube structure in which one end is closed and an inner tube and an outer tube communicate with each other at the closed end.
The oxidation heat generation layer is at least partially filled with an oxidation catalyst, and is located in a gap between the outer tube and the inner tube,
The reforming layer is at least partially filled with a reforming catalyst, and is located in the inner pipe,
The oxidation self-heat type reformer further comprising: a mixture supply channel for supplying the mixture into the inner tube of the reaction tube; and a reformed gas discharge channel for discharging the reformed gas from the gap. Quality equipment. The other end of the reaction tube opposite to the one end is provided with a channel portion having the mixture supply channel and the reformed gas discharge channel,
At the other end, the mixture supply channel is connected to the inner pipe, and the reformed gas discharge channel is connected to the gap,
The said flow path part WHEREIN: The said reformed gas discharge flow path is located in the side near the connection part of the said outer tube and the said flow path part from the said mixture supply flow path. An oxidation autothermal reformer described in 1. Having a plurality of the reaction tubes,
The oxidation autothermal reforming apparatus according to claim 1 or 2, wherein the mixture supply channel and the reformed gas discharge channel of each reaction tube are common.   An inlet portion of the mixture to the mixture supply channel and an outlet portion of the reformed gas from the reformed gas discharge channel are located on opposite sides of the reaction tube, respectively. The oxidation autothermal reformer according to any one of claims 1 to 3.   5. The oxidation self-heating reforming according to claim 2, wherein the heating means heats the inside of the reaction tube by flowing the high-temperature combustion gas in a direction from the one end toward the other end. Quality equipment.   The oxidizing gas supply means is an oxidizing gas supply pipe disposed inside the inner pipe and extending from the reformed layer of the reaction pipe to the one end side. 6. The oxidation autothermal reformer according to any one of 5 above.   The oxidation autothermal reformer according to any one of claims 1 to 6, wherein the reforming catalyst contains Ru.   The oxidation autothermal reformer according to any one of claims 1 to 7, wherein the raw material is at least one selected from the group consisting of light oil, kerosene, gasoline, and naphtha. An oxidation autothermal reformer according to any one of claims 1 to 8,
A fuel cell that uses the reformed gas discharged from the oxidation autothermal reformer as fuel; and
A combustion apparatus that burns off-gas discharged from the fuel cell to generate off-gas combustion gas;
With
The fuel cell system, wherein the high-temperature combustion gas is the off-gas combustion gas. An oxidation autothermal reformer according to any one of claims 1 to 8,
A fuel cell that uses the reformed gas discharged from the oxidation autothermal reformer as fuel; and
A first combustion device that burns off-gas discharged from the fuel cell to produce off-gas combustion gas;
A second combustion device that burns hydrocarbons or aliphatic alcohols to produce burner combustion gases;
With
The fuel cell system, wherein the high-temperature combustion gas is the off-gas combustion gas and / or the burner combustion gas.   The fuel cell system according to claim 9 or 10, wherein the fuel cell is a solid oxide fuel cell.

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