JP2005174551A - Solid oxide fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical solid oxide fuel cell (SOFC) which has a concrete device constitution to supply a high temperature reaction heat of the SOFC to an endothermic reaction process of such as a lower hydrocarbon reforming device, considering a developing situation of a conventional technology regarding a compound system of the SOFC and the endothermic reaction device. <P>SOLUTION: This is the solid oxide fuel cell having a built-in endothermic reaction container, and as for the solid oxide fuel cell, a cylindrical solid oxide cell and the endothermic reaction container in which a reaction catalyst is internally installed are arranged in the heat insulating container, the fuel is supplied to the cylindrical interior of the cylindrical solid oxide cell, an oxidizer is supplied to the cylindrical exterior, the high temperature reaction heat is generated while generating electricity, the reaction heat of the cylindrical solid oxide cell is supplied to the endothermic reaction container as the reaction heat by a radiation heat and a convection heat in which the oxidizer is used as a heating medium, a raw material is supplied to the endothermic reaction container, and the reactant is formed by the endothermic reaction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solid oxide fuel cell formed by combining endothermic reaction vessels.

  A solid oxide fuel cell (SOFC) uses an oxygen ion conductor as an electrolyte, hydrogen, carbon monoxide, or a mixed gas thereof as fuel, and oxygen in the air as an oxidant at a high temperature of 600 to 1000 ° C. This is a high-temperature fuel cell that operates on. In order to stabilize the power generation reaction, this type of battery removes the high-temperature reaction heat after the electrochemical reaction by supplying a large amount of oxidant air.

In order to use the high-temperature exhaust heat from the above-mentioned SOFC to a higher degree and to improve the utilization efficiency of the primary energy to be input, research and development on the combination of SOFC and power generators is underway in each direction. Research and development of cogeneration equipment by combining a gas turbine engine and a high-temperature fuel cell such as SOFC that supplies high-temperature exhaust gas containing unused fuel from high-temperature fuel cells such as (For example, refer to Patent Document 1 and Patent Document 2.)
Japanese Patent Laying-Open No. 2003-123778 (FIG. 1 in the same gazette) Japanese Patent Laying-Open No. 2003-45455 (FIG. 11 in the same gazette)

  Such compounding with power generators, etc., obtains engine energy using high-temperature exhaust heat exhausted from the SOFC, and the compounding of the SOFC and the engine becomes complicated and depends on the electrochemical reaction. There were problems such as being restricted in operation due to the combination of the fast system and the slow system associated with the use of off-gas heat engines.

In contrast, the present inventors combined SOFC with a lower hydrocarbon direct reformer, which is an endothermic reaction device, and mixed the high-temperature exhaust gas of SOFC with the raw material gas. A system that is arranged in an insulated container and directly supplies the reaction heat of the reforming reaction by heat transfer has been developed, and research and development for its practical use has been continued (see Patent Document 3).
Japanese Patent Laying-Open No. 2003-7321 (claim 1 in the same publication)

Direct reforming of lower hydrocarbons directly involves lower hydrocarbon-containing raw materials such as methane containing 1 to 5 carbon atoms in the molecule, such as natural gas, biogas, coke oven off gas, etc., in the presence of a metal-supported metallosilicate catalyst. This is a reforming technique known from the following patent documents as a method for reforming and co-producing hydrogen and aromatic hydrocarbons such as benzene and naphthalene.
JP 10-272366 A Japanese Patent Laid-Open No. 11-47606 Japanese Patent Laid-Open No. 11-60514 JP 2001-334151 A JP 2001-334152 A JP 2002-336704 A

  The direct reforming of the above-mentioned lower hydrocarbon-containing raw material is performed at a temperature of 300 to 800 ° C., preferably 450, with the lower hydrocarbon-containing raw material as a metal-supported metallosilicate catalyst by a flow-type reaction mode such as a fixed bed, moving bed or fluidized bed. Although it is performed by contacting at a high temperature of ˜775 ° C., more preferably 705 ° C. to 750 ° C., the technique disclosed in Patent Document 3 includes a SOFC and a direct reformer configured as separate bodies, respectively. Although it was arranged in a heat insulating container and directly supplied reaction heat to the reformer by heat transfer, a specific apparatus configuration for exchanging high-temperature exhaust heat of SOFC was not clarified.

  In view of the development status of the prior art related to such a combined system of SOFC and endothermic reactor, the present invention provides a specific method for supplying the high-temperature reaction heat of SOFC to an endothermic reaction process such as a lower hydrocarbon reformer. An object of the present invention is to provide a cylindrical solid oxide fuel cell having an apparatus configuration.

  The invention of claim 1 is a solid oxide fuel cell 00 containing an endothermic reaction vessel 20, and the solid oxide fuel cell 00 reacts with a cylindrical solid oxide cell 10 in a heat insulating vessel 40. An endothermic reaction vessel 20 having a catalyst 30 installed therein, fuel gas is supplied to the inside of the cylindrical solid oxide cell 10 and oxidant is supplied to the outside of the cylinder to generate power and generate high-temperature reaction heat. The reaction heat of the cylindrical solid oxide cell 10 is supplied as reaction heat to the endothermic reaction vessel 20 by radiant heat and heat transfer using an oxidizing agent as a heat medium, and the endothermic reaction vessel 20 is supplied with raw materials, Provided is a solid oxide fuel cell characterized in that a reactant is generated by an endothermic reaction.

  The invention of claim 2 is a solid oxide fuel cell 00 containing an endothermic reaction vessel 20, and the solid oxide fuel cell 00 reacts with a cylindrical solid oxide cell 10 in a heat insulating vessel 40. An endothermic reaction vessel 20 having a catalyst 30 therein, an oxidant is supplied to the inside of the cylindrical solid oxide cell 10 and a fuel gas is supplied to the outside of the cylinder to generate power and generate high-temperature reaction heat. The reaction heat of the cylindrical solid oxide cell 10 is supplied as reaction heat to the endothermic reaction vessel 20 by radiant heat and heat transfer using fuel gas as a heat medium, and the endothermic reaction vessel 20 is supplied with raw materials, Provided is a solid oxide fuel cell characterized in that a reactant is generated by an endothermic reaction.

  The invention according to claim 3 is characterized in that the raw material supplied to the endothermic reaction vessel 20 is mainly composed of a mixed gas composed of methane gas and either water vapor or carbon dioxide. A solid oxide fuel cell according to claim 2 is provided.

  In the endothermic reaction vessel 20 of the present invention, the reaction catalyst 30 is a lower hydrocarbon direct reforming catalyst, and a lower hydrocarbon-containing gas such as methane gas is supplied as a raw material. The solid oxide fuel cell according to any one of claims 1 to 3, wherein the solid oxide fuel cell is a lower hydrocarbon direct reforming reaction vessel.

  In the invention of claim 5, at least one of the reactants generated in the endothermic reaction vessel 20 is hydrogen, and the hydrogen is separated by the hydrogen separator 25 and supplied to the cylindrical solid oxide cell 10 as fuel. The solid oxide fuel cell according to claim 1, wherein the solid oxide fuel cell is stored in the hydrogen storage unit 50.

  In the invention of claim 6, the amount of heat of reaction generated in the cylindrical solid oxide cell 10 is Q, and the amount of heat removed from the cylindrical solid oxide cell 10 to the outside of the heat insulating container 40 by the oxidant is Q1, Provided with means for adjusting the supply amounts of either or both of the raw material and the oxidizing agent so that Q2 ≦ Q−Q1 always when the amount of heat of the endothermic reaction in the endothermic reaction vessel 20 is Q2. A solid oxide fuel cell according to any one of claims 1 and 3 to 5 is provided.

  In the invention of claim 7, the amount of heat of reaction heat generated in the cylindrical solid oxide cell 10 is Q, and the amount of heat removed from the cylindrical solid oxide cell 10 to the outside of the heat insulating container 40 by the fuel gas is Q1. Provided with means for respectively adjusting the supply amount of either the raw material or the fuel gas or both so that Q2 ≦ Q−Q1 when the heat quantity of the endothermic reaction in the endothermic reaction vessel 20 is Q2. A solid oxide fuel cell according to any one of claims 2 to 5 is provided.

  According to the present invention, in view of the development status of conventional technology related to a combined system of an SOFC in which utilization of high-temperature exhaust heat is a problem and an endothermic reaction apparatus in which high-temperature heat supply is a problem, the high-temperature reaction heat of SOFC is converted into low carbonization. A cylindrical solid oxide fuel cell having a specific device configuration for supplying to an endothermic reaction process such as a hydrogen reformer can be provided.

  FIG. 1 shows a basic system configuration of the invention of claim 1 of the present application. In the solid oxide fuel cell 00 of the present application, a cylindrical solid oxide cell 10 and an endothermic reaction vessel 20 in which a reaction catalyst 30 is provided are disposed in a heat insulating vessel 40.

  The cylindrical solid oxide cell 10 is formed by laminating fuel cell constituent members on the outer surface of a cylindrical porous ceramic base material, and is installed by penetrating up and down in the heat insulating container, or one end of the cylinder is sealed. It is stopped and suspended in the heat insulating container from the upper part of the heat insulating container. In any case, the cylindrical solid oxide cell is provided with a fuel gas or oxidant supply device (see FIG. 5) outside the heat insulating container 40 for supplying fuel gas or oxidant into the cylinder and discharging gas after power generation reaction. (Not shown) and a gas discharge device after power generation reaction (not shown) (FIGS. 2a and 2b).

  The endothermic reaction vessel 20 is made of a material resistant to the SOFC reaction temperature (approximately 600 ° C. to 1000 ° C.), and is juxtaposed with the cylindrical solid oxide cell 10 so as to vertically penetrate the heat insulating vessel 40. It is installed or accommodated in the heat insulating container 40 (FIGS. 3a and 3b).

  The cylindrical solid oxide cell 10 is supplied with fuel gas inside or outside the cylinder surface and supplied with an oxidant on the other cylinder surface, causing a power generation reaction to generate high-temperature reaction heat (approximately 600 ° C. to approximately 600 ° C.). 1000 ° C.), and the reaction heat is transferred to the endothermic reaction vessel 20 by radiant heat from the cylindrical outer surface of the cylindrical solid oxide cell 10, and unreacted air inside the heat insulating vessel 40 is used as a heat medium. Heat is supplied to the endothermic reaction vessel 20.

  In the endothermic reaction vessel 20, raw materials are supplied in the presence of the reaction catalyst 30, and an endothermic reaction is generated by heat of approximately 600 ° C. to 1000 ° C. supplied from the cylindrical oxide cell 10 to generate a reactant. The target reaction heat of the endothermic reaction can be adjusted by adjusting the feed rate of the raw material supplied to the endothermic reaction vessel.

  Since the endothermic reaction of the endothermic reaction vessel 20 occurs in the heat insulating vessel 40, the heat of reaction of the solid oxide cell 10 is absorbed to prevent overheating of the cell, and the exhaust heat of the solid oxide fuel cell 00 as a whole. Reduce the occurrence of

  Further, according to the invention of claim 6 or claim 7 of the present application, the amount of oxidant supplied to the reaction heat Q generated in the solid oxide cell 10 during rated power generation is set to the amount of heat absorbed in the endothermic reaction vessel 20. The surplus heat obtained by subtracting Q2 can be adjusted to a supply amount sufficient to be discharged as Q1, the amount of exhaust heat by the oxidant can be reduced, and the thermal efficiency of the entire apparatus can be optimized.

  In the conventional SOFC, in order to cool the solid oxide cell 10, it is necessary to send more air than necessary for the reaction into the heat insulating container, and the air utilization rate in the power generation reaction is 10 to 20%. As a result, the efficiency of the entire apparatus was lowered. In addition, a large amount of high-temperature exhaust air is generated, and it is necessary to improve the energy efficiency of the entire apparatus by combining heat utilization with lower efficiency outside the heat insulating container. The present invention efficiently removes the high-temperature reaction heat of the conventional SOFC, and uses the heat for the endothermic reaction, thereby combining power generation and material production to create an extremely high-efficiency device. Can be realized.

  In particular, as in the invention of claim 3 of the present application, the lower hydrocarbon direct reforming reaction for reforming lower hydrocarbons such as methane gas into hydrogen and aromatic hydrocarbons by an endothermic reaction at approximately 750 ° C. is performed by SOFC. The reaction heat can be used efficiently, which is extremely suitable. According to the present invention, the thermal problems related to the use of high-temperature exhaust heat of SOFC and the supply of high-temperature reaction heat of the lower hydrocarbon direct reformer can be solved in a complementary manner.

  Furthermore, the present invention is not limited to the direct lower hydrocarbon reforming reaction, and can be applied to integration of any high temperature endothermic reaction process and SOFC. For example, a reaction process such as a steam reforming reaction of methane gas, a carbon dioxide reforming reaction of methane gas, or a dehydrogenation reaction of a hydride (for example, hydrogenated aromatic hydrocarbon) is performed in the endothermic reaction vessel 20 of the present invention. It can be carried out.

  The fuel gas supplied to the cylindrical solid oxide cell 10 is either hydrogen or carbon monoxide, or a mixed gas thereof, and is supplied from a fuel supply unit (not shown). Further, in the previous stage of the fuel supply unit (not shown), the raw fuel may be reformed to generate either hydrogen or carbon monoxide or a mixed gas thereof. The raw fuel in this case is natural gas, methane gas, methane hydrate, coke oven gas, coal distillate gas (COG), coal gasification gas, biogas obtained by fermenting human waste, garbage, etc. (fermented methane gas) In addition, dry distillation or pyrolysis gas, liquefied petroleum gas, butane gas, and the like obtained by high-temperature treatment of organic materials such as wood can be used. In addition to this, any raw fuel can be used as long as it is a hydrocarbon-containing fuel and generates either hydrogen or carbon monoxide or a mixed gas thereof by reforming.

  In any reaction process, when the raw material is part or all of methane gas, the raw material is also used as a raw fuel for the cylindrical solid oxide cell 10, so that the supply system and the control system can be simplified. At the same time, when there is unreacted methane gas in the reaction process of the endothermic reaction vessel 20 and the reactants can be selectively separated, fuel gas is generated using the unreacted methane gas as a raw fuel, and cylindrical solid oxidation is performed. The object cell 10 can be reused.

  Similarly, when the reaction product in the endothermic reaction vessel 20 is hydrogen as in the invention of claim 4 of the present application, the hydrogen is selectively separated by the hydrogen separation means 25, and the product is a hydrogen storage unit. 50 or may be supplied as fuel to the cylindrical solid oxide cell 10 (FIG. 4). Naturally, when there is unreacted methane gas simultaneously with hydrogen, fuel gas can be generated using these as raw fuel and supplied to the cylindrical solid oxide cell 10.

  The oxidizing agent used in the present invention may be any oxygen-containing gas such as air or oxygen gas.

  In the present invention, from the present practical feasibility, the SOFC having the cylindrical solid oxide cell 10 has been invented. However, the endothermic reaction container of the present invention is contained in the container containing the power generation reaction part. 20 can be installed, SOFC having a flat plate type solid oxide cell and a molten carbonate fuel cell (MCFC) can replace the cylindrical solid oxide cell 10 with the same configuration of the present invention. Can be used. For this reason, use of SOFC having a flat plate type solid oxide cell or MCFC is also included in the scope of the technical idea of the present invention.

  The present invention is not limited to the above description, and various modifications can be made within the scope of the invention described in the claims of the present application, and they are also included in the scope of the present invention. Not too long.

  1 shows a basic system configuration of the present invention.   The example of installation of the cylindrical solid oxide cell in a heat insulation container is shown. a shows what penetrates a heat insulation container, b shows what is suspended in a heat insulation container.   The example of installation of the endothermic reaction container in the heat insulation container is shown. a shows what penetrates a heat insulation container, b shows what is installed in a heat insulation container.   A system configuration in which hydrogen generated in an endothermic reaction vessel is selectively separated and stored or used as a fuel for SOFC is shown (case where fuel and hydrogen are supplied into a cylinder of a cylindrical solid oxide cell).

Explanation of symbols

00 Solid oxide fuel cell
10 Cylindrical solid oxide cell
20 Endothermic reaction vessel
25 Hydrogen separation means
30 reaction catalyst
40 Insulated container
50 Hydrogen storage

Claims (7)

A solid oxide fuel cell (00) containing an endothermic reaction vessel (20),
The solid oxide fuel cell (00) includes a cylindrical solid oxide cell (10) and an endothermic reaction vessel (20) provided with a reaction catalyst (30) in a heat insulating vessel (40). The fuel gas is supplied to the inside of the cylindrical solid oxide cell (10) and the oxidant is supplied to the outside of the cylinder to generate power and generate high-temperature reaction heat,
The reaction heat of the cylindrical solid oxide cell (10) is supplied as reaction heat to the endothermic reaction vessel (20) by radiant heat and heat transfer using an oxidant as a heat medium,
A solid oxide fuel cell characterized in that the endothermic reaction vessel (20) is supplied with raw materials and produces a reactant by an endothermic reaction. A solid oxide fuel cell (00) containing an endothermic reaction vessel (20),
The solid oxide fuel cell (00) includes a cylindrical solid oxide cell (10) and an endothermic reaction vessel (20) provided with a reaction catalyst (30) in a heat insulating vessel (40). The oxidant is supplied to the inside of the cylindrical solid oxide cell (10), the fuel gas is supplied to the outside of the cylinder to generate power and generate high-temperature reaction heat,
The reaction heat of the cylindrical solid oxide cell (10) is supplied as reaction heat to the endothermic reaction vessel (20) by heat transfer using radiant heat and fuel gas as a heat medium,
A solid oxide fuel cell characterized in that the endothermic reaction vessel (20) is supplied with raw materials and produces a reactant by an endothermic reaction. The raw material supplied to the endothermic reaction vessel (20) is mainly composed of a mixed gas composed of methane gas and either water vapor or carbon dioxide. Solid oxide fuel cell In the endothermic reaction vessel (20), the reaction catalyst (30) is a lower hydrocarbon direct reforming catalyst, and a lower hydrocarbon-containing gas such as methane gas is supplied as a raw material to produce hydrogen and aromatic hydrocarbons. The solid oxide fuel cell according to any one of claims 1 to 3, which is a lower hydrocarbon direct reforming reaction vessel. At least one of the reactants generated in the endothermic reaction vessel (20) is hydrogen, and the hydrogen is separated by a hydrogen separation means (25) and supplied to the cylindrical solid oxide cell (10) as fuel. Or a hydrogen storage unit (50), wherein the solid oxide fuel cell according to any one of claims 1 to 4 is stored. The amount of heat of reaction generated in the cylindrical solid oxide cell (10) is defined as Q, and the amount of heat removed from the cylindrical solid oxide cell (10) to the outside of the heat insulating container (40) by the oxidant is defined as Q1. Means for adjusting the supply amounts of either the raw material and the oxidizing agent or both so that Q2 ≦ Q−Q1 is always satisfied, where Q2 is an endothermic heat quantity in the endothermic reaction of the reaction vessel (20). The solid oxide fuel cell according to claim 1, further comprising: a solid oxide fuel cell according to claim 1; The amount of heat of reaction generated in the cylindrical solid oxide cell (10) is defined as Q, and the amount of heat removed from the cylindrical solid oxide cell (10) to the outside of the heat insulating container (40) by the fuel gas is defined as Q1. Means for adjusting the supply amount of either the raw material and / or the fuel gas so that Q2 ≦ Q−Q1 always when the heat absorption amount in the endothermic reaction of the reaction vessel (20) is Q2. A solid oxide fuel cell according to any one of claims 2 to 5, further comprising:

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