JP2007098314A - Reactor and reformer for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor and a reformer for a fuel cell which are hard to generate a dispersion of a reaction temperature in a catalyst layer as a reaction gas does not drift, and makes the catalyst effectively work to perform a good reaction. <P>SOLUTION: The reactor and the reformer for the fuel cell have a reaction part which is formed in the shape of an outer cylinder surrounding a periphery side of a heating medium passage, is arranged with an inlet of the reaction gas at an opening end arranged at an end, and has a blocking end at the other end, the reaction catalyst layer packed in the reaction part, and a reaction product-gas returning passage, which keeps the heating medium passage wound from the blocking end towards the opening end to be spirally circled in the reaction catalyst layer and which has an outlet of a reaction product gas opened at the blocking end. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reactor and a reformer for a fuel cell.

  In general, a reaction apparatus is widely used in which a reaction gas is supplied to a reaction catalyst layer filled therein to react. For example, in the fuel cell system 101 shown in FIG. 4, a reformer 104 that produces a reformed gas by a reaction between a hydrocarbon raw material and water, and a combination of carbon monoxide or unreacted hydrocarbon and steam in the reformed gas. A shift reactor 105 that produces hydrogen by the reaction and produces a reformed gas having an increased hydrogen content, and a reformed gas that oxidizes the remaining carbon monoxide to reduce the carbon monoxide concentration as much as possible. And a carbon monoxide (CO) selective oxidizer 106. In this fuel cell system, hydrogen-rich reformed gas having a reduced carbon monoxide content generated by the reformer 104, the shift reactor 105, and the carbon monoxide (CO) selective oxidizer 106 is converted into a fuel cell stack. By supplying air to the anode 111 of 110 and supplying air to the cathode 112, power generation is performed by an electrochemical reaction between hydrogen and oxygen. As a reformer 104, a shift reactor 105, and a carbon monoxide selective oxidation reactor 106 in the fuel cell system 101, a catalyst layer is provided therein, and each reaction is performed while a reaction gas flows through the catalyst layer. A type of device is used.

  For example, Patent Document 1 describes a fuel cell reformer having a reaction tube filled with a reforming catalyst and a heat transfer portion surrounding the reaction tube (see Patent Document 1 and the like). Further, as shown in FIG. 5, a heating medium flow passage 51 through which the heating medium HF flows, and a reaction section 52 formed in an outer cylindrical shape surrounding the outer peripheral side of the heating medium flow passage 51 and filled with a reaction catalyst, There is also known a reaction apparatus that heats the reaction gas RG flowing through the catalyst layer of the reaction section 52 by the heating medium flowing through the heating medium flow passage 51 and reacts in the presence of the catalyst.

In a reaction apparatus of a type in which a reaction gas is circulated and reacted in such a catalyst layer, if a drift of the reaction gas occurs in the catalyst layer, a part not involved in the reaction (dead part) is generated. Therefore, in each part of the catalyst layer, Variations in the reaction temperature occur, resulting in a portion where the catalyst does not function effectively. Therefore, in the worst case, the reaction in the catalyst layer does not reach equilibrium, and there is a possibility that part or all of the reaction gas is led out from the reaction apparatus in an unreacted state.
Japanese Patent Laid-Open No. 06-231789 (paragraph number 0006, FIG. 2)

  Accordingly, the present invention solves the above-mentioned problems, and since the reaction gas does not drift, the reaction temperature in the catalyst layer is unlikely to vary, and the reaction apparatus and the fuel cell capable of performing a good reaction with the catalyst functioning effectively An object of the present invention is to provide an industrial reformer.

  According to the first aspect of the present invention, there is provided a heating medium flow passage through which a heating medium flows, and an outer cylindrical shape surrounding an outer peripheral side of the heating medium flow passage, and a reaction gas inlet at an open end provided at one end. And a reaction part having a closed end at the other end, a reaction catalyst layer filled in the reaction part, and the heating medium flow path from the closed end toward the open end inside the reaction catalyst layer And a reaction product gas return pipe provided with a reaction product gas outlet opening opened at the closed end and provided in a spiral shape.

  In this reaction apparatus, the heating medium flow passage is wound around the reaction catalyst layer provided in the reaction section from the closed end toward the open end, and the reaction medium opens in the closed end. By providing a reaction product gas return pipe with a product gas outlet, the reaction gas does not flow unevenly in the catalyst layer of the reaction part, so that the reaction temperature is less likely to vary, and the catalyst functions effectively and performs the reaction stably. Can be made.

  The invention according to claim 2 is a reformer for a fuel cell that produces a hydrogen-containing gas by a reaction between a hydrocarbon raw material and water, a heating medium flow passage through which a heating medium flows, and the heating medium The reforming reaction section is formed in an outer cylindrical shape surrounding the outer peripheral side of the flow path, the hydrocarbon raw material and water introduction port is provided at an open end provided at one end, and the closed end is provided at the other end, and the modified A reforming catalyst layer filled in a mass reaction section, and inside the reforming catalyst layer, the heating medium flow passage is wound from the closed end toward the open end, and spirally swung, A reformer for a fuel cell, comprising: a hydrogen-containing gas return pipe having a hydrogen-containing gas outlet opening opened at a closed end.

  In this fuel cell reforming apparatus, the heating medium flow passage is wound from the closed end toward the open end inside the reforming catalyst layer filled in the reforming reaction section, and spirally swirled. And a hydrogen-containing gas return pipe having a hydrogen-containing gas outlet opening opened at the closed end, so that the reaction gas does not flow unevenly in the catalyst layer of the reforming reaction section, and the reaction temperature is less likely to vary. Can function effectively and allow the reaction to be performed stably.

  In the reaction apparatus of the present invention, the reaction gas introduced into the reaction section reacts while swirling the catalyst layer by forming the reaction product gas return pipe provided in the catalyst layer in a spiral shape. Therefore, it is difficult to form a dead part in the catalyst layer, and as a result, the reaction part is less likely to vary in reaction temperature, so that the reaction in the catalyst layer of the reaction part can be easily controlled and the reaction can be performed stably. It becomes possible.

  According to another aspect of the present invention, there is provided a reformer for a fuel cell in which the hydrogen-containing gas return pipe provided in the catalyst layer in the reforming reaction section is formed in a spiral shape so that the reaction gas introduced into the reforming reaction section is a catalyst. React with swirling layers. Therefore, it is difficult to form a dead part in the catalyst layer, and as a result, the reaction temperature is less likely to vary in the reforming reaction part. Therefore, the reforming reaction between the hydrocarbon raw material and water in the catalyst layer of the reforming reaction part is prevented. It is easy to control and the reforming reaction can be performed stably.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is a schematic diagram showing the configuration of the reaction apparatus according to the first embodiment of the present invention, and FIG. 2 is a conceptual diagram showing a part of the reaction apparatus cut away.

  This reaction apparatus 1 is provided with a heating medium flow passage 12 penetrating the axial center of a tubular apparatus main body 11 and an outer peripheral side of the heating medium flow path 12, and a reaction section in which a reaction catalyst layer 14 is provided. 13 and a double tube structure.

  The heating medium flow passage 12 is a flow path through which the heating medium HF that passes through the axial center of the apparatus main body 11 and is heated by a burner (not shown) or the like flows. The heating medium flow passage 12 is for heating the reaction gas flowing through the reaction catalyst layer 14 in the reaction section 13 via the inner peripheral wall 11 a of the apparatus main body 11. In addition, the reaction part 13 can also be efficiently heated by providing a heat transfer promoting member such as a fin on the inner peripheral wall 11a.

The reaction unit 13 surrounds the outer peripheral side of the heating medium flow passage 12 and is formed in an outer cylindrical shape between the inner peripheral wall 11a and the outer peripheral wall 11b of the apparatus main body 11, and is separated from the heating medium flow passage 12 by the inner peripheral wall 11a. It is made. The reaction unit 13 has an open end 13a at one end and a closed end 13b at the other end, and a reaction gas inlet 13c is provided at the open end 13a.
The reaction unit 13 includes a reaction catalyst layer 14 formed by filling a reaction catalyst between the inner peripheral wall 11a and the outer peripheral wall 11b, and a reaction product gas return pipe disposed inside the reaction catalyst layer 14. Road 15 is provided.

  The reaction product gas return pipe 15 includes a reaction product gas outlet 15a that opens to the closed end 13b, a pipe body 15b that spirals around the reaction catalyst layer 14 around the heating medium flow path 12, and The pipe body 15b has a reaction product gas outlet 15c led out of the reaction section 13 from the open end 13a. The reaction product gas outlet 15c is connected to another device. For example, when the reactor 1 is a fuel cell reformer, the reaction product gas outlet 15c is connected to a gas inlet of the shift reactor. Here, the outer diameter R of the pipe main body 15 b of the reaction product gas return pipe 15 is configured such that R <L with respect to the distance L between the inner peripheral wall 11 a and the outer peripheral wall 11 b of the apparatus main body 11. Is done. That is, as shown in FIG. 2, gaps 16 a and 16 b are formed between the pipe main body 15 a of the reaction product gas return pipe 15 and the inner peripheral wall 11 a and the outer peripheral wall 11 b of the apparatus main body 11. The reaction gas is configured to pass through 16a and 16b. At this time, R / L is selected in the range of 0.5 to 1.0, and the assembly work for inserting the reaction product gas return pipe 15 into the reactor 1 is facilitated by taking a wide gap, The filling operation of the catalyst into the reactor 1 is also facilitated.

  In this reaction apparatus 1, the reaction gas is introduced from the reaction gas introduction port 13 c, and swirls around the reaction gas flow path 16 formed in a spiral shape by the reaction product gas return pipe 15 in the reaction catalyst layer 14. It flows toward the closed end 13b. In addition, as shown in FIG. 2, the reaction gas can pass through the gaps 16a and 16b and flow to the next reaction gas flow passage. By passing the reaction gas through the gaps 16a and 16b, the flow of the reaction gas around the reaction product gas return pipe 15 can be promoted to effectively use the reaction catalyst. The reaction gas is heated by the heating medium flowing through the heating medium flow passage 12 and reacts by the action of the reaction catalyst that forms the reaction catalyst layer 14. At this time, the reaction gas does not drift in the reaction catalyst layer 14 and smoothly flows in the reaction catalyst layer 14. Therefore, variations in reaction temperature in the reaction catalyst layer 14 are unlikely to occur, and the catalyst can function effectively and perform a good reaction. The reaction product gas containing the product generated by the reaction is introduced into the reaction product gas return pipe 15 from the reaction product gas outlet 15a opened at the closed end 13b, and reacts while spirally turning in the reaction catalyst layer 14. It circulates in the pipe body 15b toward the product gas outlet 15c. At this time, the reaction product gas exchanges heat with the reaction gas flowing through the reaction catalyst layer 14 while flowing through the pipe body 15b, thereby heating the reaction gas. Accordingly, the thermal energy of the reaction product gas can be effectively used for heating the reaction gas, and can be introduced into the subsequent reactor or apparatus as a gas having an appropriate temperature.

Specific examples of the reactor 1 according to the first embodiment include a fuel cell reforming reactor, a fuel cell steam reforming reactor, a fuel cell partial oxidation reforming reactor, a shift reactor, and a carbon monoxide selection. An oxidation reaction apparatus is mentioned. For example, a reformer for a fuel cell that uses a reaction gas in the reactor 1 as a mixed gas of a hydrocarbon raw material and water vapor and uses a reforming catalyst as a reaction catalyst can be configured. In this fuel cell reformer, the reaction product gas is a hydrogen-containing gas. Therefore, this fuel cell reforming apparatus is a fuel cell reforming apparatus for producing a hydrogen-containing gas by a reaction between a hydrocarbon raw material and water, a heating medium flow passage through which a heating medium flows, and the heating medium. The reforming reaction section is formed in an outer cylindrical shape surrounding the outer peripheral side of the flow path, the hydrocarbon raw material and water introduction port is provided at an open end provided at one end, and the closed end is provided at the other end, and the modified A reforming catalyst layer filled in a mass reaction section, and inside the reforming catalyst layer, the heating medium flow passage is wound from the closed end toward the open end, and spirally swung, A reformer for a fuel cell comprising a hydrogen-containing gas return pipe having a hydrogen-containing gas outlet opening opened at the closed end can be configured. The hydrogen-containing gas produced by this reforming reactor is a reactor in the subsequent stage such as a shift reactor that constitutes the fuel cell system, a processing device such as a H ₂ permeable membrane, a solid oxide fuel cell (SOFC) solid oxide fuel. In the case of a battery) system, it is directly led to the fuel cell stack through a hydrogen-containing gas lead-out path.

  At this time, the reforming reaction in the reforming reaction section is performed in the presence of the reforming catalyst, for example, at a reforming reaction temperature in the range of 550 to 700 ° C., between the hydrocarbon content contained in the hydrocarbon raw material and steam. The reaction produces a hydrogen-containing gas. Examples of the reforming catalyst used include noble metal catalysts such as platinum (Pt), palladium (Pd), and ruthenium (Ru). These reforming catalysts are supported on porous ceramic particles. The porous reaction product is filled in the inside of the quality reaction part to form a catalyst layer.

  The hydrocarbon raw material supplied to the reforming reaction section is not particularly limited as long as hydrogen can be produced by the reforming reaction in the reforming reaction section of the fuel cell reforming apparatus. Examples include kerosene, light oil, heavy oil, asphaltene, oil sand oil, methanol, naphtha, coal liquefied oil, coal heavy oil, liquid hydrocarbon mixtures such as gasoline, gaseous hydrocarbon mixtures such as city gas and LPG, etc. Can be used. Among these, kerosene has a very high energy density as a hydrogen source and is highly portable and storable, and is therefore suitable as a hydrocarbon raw material for a small stationary fuel cell system for home use. When these hydrocarbon raw materials contain a large amount of sulfur, it is desirable to desulfurize them with a desulfurization apparatus before supplying them to the reforming reaction section. If the hydrocarbon raw material to be used is low in sulfur content and can be supplied to the reforming reaction in the reforming reaction section, the hydrocarbon raw material is directly supplied to the reforming reaction section by omitting the desulfurization unit. can do.

Further, as the reaction apparatus 1, a shift reaction apparatus of a fuel cell system can be configured. At this time, the reaction gas is a hydrogen-containing gas generated by the reforming reaction apparatus. This shift reactor was produced by a fuel cell reformer at a temperature of, for example, 150 to 300 ° C. in the presence of a shift catalyst (reaction catalyst) such as iron oxide, copper-zinc, or copper-chromium. Carbon monoxide is converted to carbon dioxide by exothermic reaction of carbon monoxide and water vapor contained in the hydrogen-containing gas (CO + H ₂ O → CO ₂ + H ₂ ), reducing the carbon monoxide concentration and further containing hydrogen. This is an apparatus for generating a hydrogen-containing gas (hereinafter referred to as “shift gas”) having an increased amount. Thereby, hydrogen contained in the hydrogen-containing gas supplied to the fuel cell stack FC is effectively used as a power generation hydrogen resource supplied to the anode of the fuel cell stack.

  Further, as the reaction apparatus 1, a carbon monoxide (CO) selective oxidation apparatus for a fuel cell system can be configured. At this time, the reaction gas is a shift gas generated in the shift reaction apparatus and having an increased hydrogen content. This carbon monoxide (CO) selective oxidizer oxidizes carbon monoxide present in a minute amount in the shift gas supplied from the shift reactor in order to avoid the problem of poisoning of the electrodes of the fuel cell stack. Is a device for supplying a hydrogen-containing gas having a further reduced carbon monoxide concentration to the fuel cell stack. Usually, in this carbon monoxide selective oxidizer, the concentration of carbon monoxide in the shift gas is reduced to 10 ppm or less. The reaction in the carbon monoxide selective oxidizer is performed at a temperature in the range of 105 to 150 ° C. in the presence of a noble metal catalyst such as platinum, ruthenium or rhodium.

It is a schematic diagram which shows the structure of the reaction apparatus which concerns on embodiment of this invention. It is a figure which notches and shows a part of reactor which concerns on embodiment of this invention. 1 is a block diagram showing a main configuration of a fuel reforming fuel cell system. It is a conceptual diagram which shows the structural example of the reaction apparatus which has a catalyst layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction apparatus 12 Heating medium flow path 13 Reaction part 13a Open end 13b Closed end 13c Inlet 14 Reaction catalyst layer 15a Reaction product gas outlet 15c Reaction product gas outlet HF Heating medium

Claims (2)

A heating medium flow path through which the heating medium flows;
A reaction part formed in an outer cylinder surrounding the outer periphery of the heating medium flow path, having a reaction gas inlet at an open end provided at one end, and a closed end at the other end;
A reaction catalyst layer filled in the reaction section;
A reaction product gas return having a reaction product gas outlet opening spirally wound around the heating medium flow path from the closed end to the open end inside the reaction catalyst layer and spirally opened. And a conduit. A reformer for a fuel cell that produces a hydrogen-containing gas by a reaction between a hydrocarbon raw material and water,
A heating medium flow path through which the heating medium flows;
A reforming reaction section that is formed in an outer cylinder surrounding the outer periphery of the heating medium flow path, the hydrocarbon raw material and water inlet is provided at an open end provided at one end, and a closed end is provided at the other end; ,
A reforming catalyst layer filled in the reforming reaction section;
Inside the reforming catalyst layer, the heating medium flow path is wound from the closed end toward the open end, spirally swirled, and provided with a hydrogen-containing gas outlet opening opened at the closed end A fuel cell reformer comprising: a gas return pipe.

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