JP2009037814A - Method for reducing temperature in high temperature region of solid oxide fuel cell and apparatus therefor - Google Patents

Abstract

A method for reducing a temperature in a high temperature range of a solid oxide fuel cell stack, system, bundle, or the like and an apparatus therefor are obtained.
In a solid oxide fuel cell system, a fuel modification for hydrogen production, which is different from a fuel supply system to the solid oxide fuel cell, is located near a solid oxide fuel cell that is in a high temperature range during operation. A method for reducing the temperature of the high temperature region of the solid oxide fuel cell system, wherein the temperature of the high temperature region is reduced using an endothermic reaction in the fuel reformer during operation And a temperature reducing device for the battery high temperature region.
[Selection] Figure 7

Description

  The present invention relates to a method for reducing a temperature in a high temperature region of a solid oxide fuel cell (hereinafter abbreviated as “SOFC” where appropriate) and an apparatus therefor, and more specifically, a high temperature cell in a SOFC stack, SOFC system or SOFC bundle. The present invention relates to a method for reducing the temperature of the battery and an apparatus for reducing the temperature of the battery high temperature region.

  The SOFC is operated at a temperature of about 700 to 1000 ° C., but its power generation performance is greatly affected by the operating temperature. For this reason, in order to draw out power generation performance properly, it is necessary to control the operating temperature to a predetermined temperature. When the operating temperature is low, the performance of the SOFC cell is degraded, and when the operating temperature is high, the deterioration and durability of the SOFC cell are problematic.

  In the SOFC, the temperature of the battery or stack in the central part rises due to internal heat generation in the battery part during operation, and a large temperature distribution, that is, a large temperature difference occurs between other parts. As shown in FIG. 1, in an SOFC stack in which a plurality of flat plate SOFC cells are stacked as an example, as shown in FIG. The temperature of the cell in the part becomes higher. Further, as shown in FIG. 2, in the SOFC system in which a plurality of SOFC stacks as shown in FIG. 1 are juxtaposed, the temperature of the SOFC stack at the center becomes higher as shown in the high temperature region in FIG. In the present specification, such high temperature portions are appropriately referred to as “high temperature region”, “battery high temperature region”, “battery high temperature region” and the like.

  By the way, the adjustment of the operating temperature of the SOFC is usually performed only by adjusting the amount of air supplied by a blower (= blower). When the SOFC temperature is high, the air amount is increased and air cooling is performed, and when the SOFC temperature is low, the air amount is decreased and the SOFC temperature is increased. When a plurality of SOFC stacks are arranged as shown in FIG. 2, the air supplied to each SOFC stack is controlled to a predetermined amount by a mass flow controller (MFC) as shown in FIG. Supplied to the cathode.

  However, adjustment by the supply air amount is not a measure for reducing the temperature distribution in the SOFC stack. Control of the temperature distribution as shown in FIGS. 1 and 2 is difficult by adjusting the air supply amount. If the temperature distribution is large, sufficient power generation performance cannot be obtained, or a high temperature region is generated locally and the battery is Problems such as affecting the durability of the product.

  In addition, in order to suppress such local temperature rise, the adoption of an internal reforming method in which fuel is reformed in the SOFC battery part and cooled using the endothermic heat of the reforming reaction is being studied. However, since the fuel supply amount and the endothermic reaction are correlated, the temperature cannot be controlled independently by internal reforming.

  The present invention has been made to solve the above-described problems in the prior art, and provides a method for reducing the temperature of a battery high temperature region and a temperature reducing device for the battery high temperature region in an SOFC stack, SOFC system or SOFC bundle. It is intended to do.

  The present invention is (1) in a solid oxide fuel cell system, in the vicinity of a solid oxide fuel cell that is in a high temperature region during operation, a hydrogen production system separate from the fuel supply system to the solid oxide fuel cell A fuel reformer for a fuel cell is disposed, and during operation, the endothermic reaction in the fuel reformer is utilized to reduce the temperature in the high temperature region. This is a temperature reduction method.

  In the temperature reduction method of the present invention (1), the degree of temperature reduction in the high temperature region can be controlled by adjusting the amount of hydrogen produced by the fuel reformer of the separate system depending on the temperature in the high temperature region.

  The present invention is (2) a solid oxide fuel cell system in which a plurality of solid oxide fuel cell stacks are juxtaposed, and of the plurality of solid oxide fuel cell stacks, a high temperature region is obtained during operation. In the vicinity of the solid oxide fuel cell stack, a fuel reformer for hydrogen production, which is different from the fuel supply system to each solid oxide fuel cell stack, is arranged. An apparatus for reducing the temperature in the high temperature range of a solid oxide fuel cell system, wherein the temperature in the high temperature range is reduced using an endothermic reaction.

  The present invention is (3) a solid oxide fuel cell system in which a plurality of solid oxide fuel cell stacks are juxtaposed, and a high temperature region is obtained during operation of the plurality of solid oxide fuel cell stacks. Between the solid oxide fuel cell stacks, a fuel reformer for hydrogen production, which is different from the fuel supply system to each solid oxide fuel cell stack, is arranged, and during the operation, the endothermic heat in the fuel reformer is disposed. A temperature reducing device for a high temperature region of a solid oxide fuel cell system, wherein the temperature of the high temperature region is reduced by utilizing a reaction.

  The present invention relates to (4) a solid oxide fuel cell system in which a plurality of cylindrical solid oxide fuel cells are arranged, and during operation of the plurality of cylindrical solid oxide fuel cells. A fuel reformer for hydrogen production separate from the fuel supply system to each cylindrical solid oxide fuel cell is placed between the cylindrical solid oxide fuel cells that are in the high temperature range. An apparatus for reducing the temperature in the high temperature range of a solid oxide fuel cell system, wherein the temperature in the high temperature range is reduced using an endothermic reaction in the fuel reformer.

  In the temperature reduction device according to the present invention (2) to (4), the degree of temperature reduction in the high temperature region of the battery is adjusted by adjusting the amount of hydrogen produced by the fuel reformer of the separate system depending on the temperature of the high temperature region of the battery. Can be controlled.

  In the conventional SOFC stack, SOFC system or SOFC bundle, the partial temperature in the battery high temperature range could not be controlled effectively and independently, but according to the present invention, the SOFC stack, By arranging a hydrogen production system consisting of a fuel reformer for hydrogen production separate from the fuel supply system to the SOFC system or SOFC bundle, it becomes possible to independently control the temperature of these high temperature parts of the battery, Regardless of the power generation amount of the SOFC stack, the SOFC system, or the SOFC bundle itself, the temperature of the battery high-temperature part can be quickly and independently controlled.

  Conventionally, SOFC stacks, SOFC systems, and SOFC bundles have been studied so as to suppress the temperature rise of the battery by utilizing a reforming reaction of raw fuel. FIGS. 3 to 4 are diagrams for explaining a mode in which the temperature rise of the battery is suppressed by using a reforming reaction, that is, an endothermic reaction, when reforming the raw fuel supplied to the SOFC system. As an example, four SOFCs are illustrated. An example of the SOFC system in which the stack is arranged is shown, and FIG. 4 shows a fuel supply system among the fuel supply system and the air supply system to each SOFC stack shown in FIG.

  In this specification, the fuel supplied for power generation in the SOFC stack, SOFC system or cylindrical SOFC bundle is referred to as “raw fuel” as appropriate. What is the fuel supply system for the SOFC stack, SOFC system or cylindrical SOFC bundle? The fuel supplied to the hydrogen reforming fuel reformer of another system is appropriately referred to as “fuel”. If the raw fuel and the fuel contain sulfur compounds, the reforming catalyst is poisoned and performance deteriorates, so the sulfur compounds are removed in advance.

  As shown in FIGS. 3 to 4, a reformer for reforming the raw fuel supplied to the SOFC system is arranged in the vicinity of the SOFC stack that becomes the high temperature region of the battery. Since the reforming reaction in the reformer is an endothermic reaction, the SOFC stack near the reformer is cooled by endotherm during the operation.

  However, in this aspect, the fuel reforming and supply system is a single system, and all the raw fuel used for power generation passes through the reformer, so the power generation amount and the heat absorption amount due to reforming cannot be controlled independently. . As a result, even when the battery temperature is locally high and it is desired to increase the fuel reforming amount to lower the temperature of the high temperature portion, the fuel reforming amount cannot be increased due to the restriction. Conversely, unless the fuel reforming amount is increased and the power generation amount is not increased, the fuel utilization rate is lowered and the power generation efficiency is lowered. On the other hand, the amount of relative heat absorption in the reformer is large, and even when the battery temperature is lowered, the reforming amount of the raw fuel cannot be reduced, and the original temperature control cannot be performed.

  In addition, in Japanese Patent No. 3781942 (hereinafter abbreviated as “942 Publication”) and Japanese Patent Application Laid-Open No. 2002-334714 (hereinafter abbreviated as “714 Publication”), etc., hydrogen is removed using the surplus heat of SOFC. A manufacturing system has been proposed.

  In Japanese Patent No. 942, the surplus heat is used for steam reforming of city gas to produce hydrogen simultaneously with power generation, and the outline is shown in FIG. As shown in FIG. 5, city gas, which is a raw fuel, is passed through a pre-reformer to generate a crude reformed gas, and then branched, one of which is supplied to the SOFC unit for power generation, and the other is used to generate excess SOFC heat as a heat source. Is supplied to a reformer, that is, a hydrogen production apparatus to produce hydrogen. The crude reformed gas is a reformed gas containing methane and CO in addition to hydrogen, and methane becomes hydrogen by internal reforming at the anode of the SOFC.

In Japanese Patent No. 714, high-purity hydrogen is produced by refining the SOFC anode off-gas, and an outline thereof is shown in FIG. As shown in FIG. 6, the raw fuel is supplied to the SOFC unit together with the steam and internally reformed to generate power, and the anode off-gas of the SOFC is passed through the purification device to produce pure hydrogen. In the purification device, pure hydrogen is produced by passing the anode off gas through, for example, a CO converter or through a CO ₂ adsorbent layer following the CO converter.

Japanese Patent No. 3781942 JP 2002-334714 A

  These prior arts focus on the use of reforming reactions in the raw fuel supply system during the power generation by the SOFC unit, and the production of hydrogen by effectively utilizing the surplus heat of the SOFC. In particular, there is no mention of performing temperature control in the high temperature range of the battery, which is a problem in the present invention. In these prior arts, since the fuel supply system is a single system, increasing the heat absorption amount by hydrogen production, that is, increasing the supply amount of raw fuel leads to an increase in the heat generation amount in the SOFC unit. .

  On the other hand, in the present invention, in the SOFC stack, the SOFC system, or the cylindrical SOFC bundle, the battery portion is in a high temperature region, and is separate from the raw fuel supply system to the SOFC stack, SOFC system, or cylindrical SOFC bundle. A fuel reformer for hydrogen production having a fuel supply system is arranged. During these operations, the temperature in the high temperature range is reduced by utilizing the endothermic reaction in the fuel reformer for hydrogen production, which is a separate system from the raw fuel supply system to the SOFC stack, SOFC system, or cylindrical SOFC bundle. To do.

  In the present invention, in addition to reducing the temperature in the high temperature range of the battery, the degree of temperature reduction in the high temperature range is controlled by controlling the amount of hydrogen produced by the fuel reformer depending on the temperature in the high temperature range of the SOFC. Can be controlled. For example, when the temperature of the SOFC stack battery high temperature region is high, the amount of hydrogen produced by the fuel reformer is increased to control the degree of temperature reduction of the battery high temperature region, and when the SOFC stack battery high temperature region temperature is low, the fuel The amount of hydrogen produced by the reformer can be reduced to control the degree of temperature reduction in the high temperature range of the battery.

  Here, the low “temperature” in “when the temperature of the SOFC battery high temperature region is low” means a temperature higher than the temperature of the portion other than the high temperature portion of the battery. In addition, the SOFC includes a flat plate type, a cylindrical type, a horizontal stripe type, and various other types. The present invention is applied to any type of SOFC.

  Hereinafter, aspects of the present invention will be sequentially described.

<Aspect 1 of the present invention>
FIG. 7 is a diagram illustrating Embodiment 1 of the present invention. FIG. 7A schematically shows a plurality of SOFC stacks, raw fuel piping systems and air piping systems to each SOFC stack, and characteristic portions of the present invention. Of these, the portion including the characteristic portions of the present invention is shown in FIG. ). FIG. 7 shows a case where the raw fuel is internally reformed in the battery part of each SOFC stack, and the raw fuel is internally reformed with steam in the battery part of each SOFC stack to generate hydrogen and carbon monoxide. Used for power generation.

  As shown in FIG. 7 (a), the fuel supply system to each SOFC stack in this SOFC system includes a pipe for supplying raw fuel and water (steam), a pipe branched therefrom and supplied to each stack, and an anode from each stack. It is composed of a pipe for discharging off-gas and supplying it to the off-gas combustor, an off-gas combustor, and the like. Among them, a pipe for supplying raw fuel and water (steam) and a pipe branching from the pipe to supply each stack are shown as “SOFC raw fuel supply line” in FIG. 7B.

  In the aspect 1 of the present invention, in addition to the raw fuel supply system to each SOFC stack, among the SOFC stacks, the SOFC stack that is in a high temperature region during operation, the SOFC stack 2 and the SOFC in FIG. A fuel reformer B for hydrogen production is disposed near the side of the stack 3. The system including the fuel reformer B is a separate fuel supply and hydrogen production system from the raw fuel supply system to each SOFC stack. What is the flow rate of raw fuel used for power generation and the fuel flow rate for hydrogen production? Each can be adjusted independently.

  As a result, the fuel flow for hydrogen production can be adjusted independently of the power generation amount in the battery part, that is, separately from the power generation amount in the battery part. Thereby, the temperature of a battery high temperature part can be reduced at the time of a driving | operation of a SOFC system independently of the electric power generation amount in a battery part. Moreover, since the degree of temperature reduction can be adjusted by adjusting the flow rate of the hydrogen production fuel to the fuel reformer B depending on the temperature of the high temperature part of the battery, the fuel for hydrogen production can be adjusted during the operation of the SOFC system. By controlling the amount of hydrogen produced by the reformer B, the degree of temperature reduction in the high temperature part of the battery can be controlled.

  Here, “controlling the amount of hydrogen produced” means that the production of hydrogen in the fuel reformer B is stopped depending on the temperature of the high temperature part of the battery.

  And by those control, the battery temperature in a battery high temperature part (SOFC stacks 2 and 3 in FIG. 7) and the battery temperature in other parts (SOFC stacks 1 and 4 in FIG. 7) are equalized or more. It can be equalized. These points also apply to <Aspect 2 of the present invention> to <Aspect 4 of the present invention> described below, and the same applies to other aspects.

  A sensor for temperature detection, such as a thermocouple, is disposed in the high temperature part of the battery in the SOFC stack, but its description is omitted in FIG. The temperature sensor is placed at a place where the battery is expected to become a high temperature part during the operation of the SOFC stack. Preferably, the place where the temperature is expected to become the highest during the operation, for example, the SOFC stack It arranges in the cell which is located in the central part.

  This also applies to <Aspect 2 of the present invention> to <Aspect 4 of the present invention> described later. Of these, the case of <Aspect 4 of the present invention> will be described as an example. In an SOFC bundle in which a plurality of cylindrical SOFC cells are arranged, a high temperature region is obtained during operation of the plurality of cylindrical SOFC cells. The temperature sensor is arranged at a place where the temperature is expected to be high, preferably at a place where the temperature is expected to be the highest during the operation, for example, a cylindrical SOFC cell located at the center of the SOFC bundle.

<Aspect 2 of the present invention>
FIG. 8 is a diagram for explaining an embodiment 2 of the present invention. FIG. 8 (a) shows the outline of the characteristic parts of the fuel and air piping system and the present invention to a plurality of SOFC stacks, and the part including the characteristic part of the present invention is shown in FIG. 8 (b). . As shown in FIG. 8, in addition to the raw fuel supply system to each SOFC stack, among the SOFC stacks, the SOFC stacks that are in the high temperature region during operation, the SOFC stack 2 and the SOFC stack 3 in FIG. A fuel reformer B for hydrogen production is disposed between them. Other configurations are the same as those described in <Aspect 1 of the present invention>.

  The system including the fuel reformer B is a hydrogen production system different from the raw fuel supply system to each SOFC stack, and the flow rate of the raw fuel supplied for power generation and the fuel flow rate for hydrogen production are independent of each other. It can be adjusted. As a result, the fuel flow for hydrogen production can be adjusted independently of the power generation amount of the battery part, that is, separately from the power generation amount of the battery part. Thereby, the temperature of a battery high temperature part can be reduced at the time of a driving | operation of the said SOFC system independently of the electric power generation amount of a battery part. In addition, the degree of temperature reduction can be adjusted by adjusting the flow rate of the hydrogen production fuel to the fuel reformer B depending on the temperature of the high temperature part of the battery. By controlling the amount of hydrogen produced by the mass device B, the degree of temperature reduction in the high temperature part of the battery can be controlled.

<Aspect 3 of the present invention>
In the third aspect of the present invention, when the raw fuel is made into a crude reformed gas by a pre-reformer, then the reformed gas supplied to the anode of the SOFC stack and internally reformed in the battery part is used as a fuel for power generation. This is an embodiment to which the present invention is applied. FIG. 9 is a diagram for explaining the aspect 3 of the present invention, and shows a case where city gas is used as a raw fuel. In FIG. 9, one or a plurality of SOFC stacks, SOFC modules, or SOFC bundles, and other SOFC structures are described as SOFC units. It is also called an SOFC system including various systems and various piping systems.

The raw fuel is desulfurized by the desulfurizer, and then introduced into the pre-reformer through the heat exchanger 1, and the raw reformed gas containing methane, hydrogen, and CO is introduced by introducing the steam from the vaporizer, that is, the steam generator. It is generated and introduced into the heat exchanger 2. The crude reformed gas is heated by the combustion gas from the off-gas combustor in the heat exchanger 2 and then supplied to the SOFC unit. Methane in the crude reformed gas is used for battery reaction by being converted into hydrogen and CO by internal reforming (CH ₄ + H ₂ O → 3H ₂ + CO) at the battery part, that is, the anode.

  In the aspect 3 of the present invention, for example, in the case of an SOFC system composed of a plurality of SOFC stacks, in addition to the raw fuel supply system to each SOFC stack, the SOFC in each SOFC stack that is in a high temperature region during operation The fuel reformer B is disposed between the SOFC stacks in the vicinity of the stack or in the high temperature region during operation. When the fuel reformer B is arranged in the vicinity of the SOFC stack that is in a high temperature region during its operation, the fuel reformer B is in the high temperature region during its operation as shown in FIG. When it is arranged between the SOFC stacks of FIG. Other configurations are the same as those in <Aspect 1 of the present invention> to <Aspect 2 of the present invention>.

  The system including the fuel reformer B is a separate hydrogen production system from the raw fuel supply system to each SOFC stack, and the flow rate of the raw fuel supplied for power generation and the fuel flow rate for hydrogen production are independent of each other. It can be adjusted. As a result, the fuel flow rate for hydrogen production can be adjusted independently of the power generation amount of the battery part, that is, separately from the power generation amount of the battery part. Thereby, the temperature of a battery high temperature part can be reduced at the time of a driving | operation of a SOFC system independently of the electric power generation amount of a battery part. Moreover, since the degree of temperature reduction can be adjusted by adjusting the flow rate of the hydrogen production fuel to the fuel reformer B depending on the temperature of the high temperature part of the battery, the fuel for hydrogen production can be adjusted during the operation of the SOFC system. By controlling the amount of hydrogen produced by the reformer B, the degree of temperature reduction in the high temperature part of the battery can be controlled.

<Aspect 4 of the present invention>
Aspect 4 of the present invention is an aspect applied to a cylindrical SOFC bundle in which a plurality of cylindrical SOFC cells are juxtaposed. FIGS. 10-11 is a figure explaining the aspect 4 of this invention, and has shown the characterizing part of this invention, respectively. As shown in FIG. 10, a plurality of cylindrical SOFC cells are divided into four groups, and in addition to the raw fuel supply system to each cylindrical SOFC cell constituting the bundle, each cylindrical type that becomes a high temperature region during its operation. A fuel reformer B for hydrogen production having a fuel supply system different from the raw fuel supply system is disposed between the SOFC cells.

  The mode shown in FIG. 11 is a case where the fuel reformer B is arranged inside the cylindrical SOFC cell in the outer peripheral region in the cylindrical SOFC bundle in which a plurality of cylindrical SOFC cells are juxtaposed. 10 to 11 show a case where a plurality of cylindrical SOFCs are divided into four groups. For example, three groups and five groups are divided into a plurality of groups, and between each group, A fuel reformer B for hydrogen production can be arranged between each cylindrical SOFC cell that is in a high temperature range during the operation. Other configurations are the same as those in <Aspect 1 of the present invention> to <Aspect 3 of the present invention>.

  The system including the fuel reformer B is a separate hydrogen production system from the raw fuel supply system to each SOFC bundle, and the flow rate of the raw fuel supplied for power generation and the fuel flow rate for hydrogen production are independent of each other. It can be adjusted. As a result, the fuel flow rate for hydrogen production can be adjusted independently of the power generation amount of the battery part, that is, separately from the power generation amount of the battery part. Thereby, the temperature of a battery high temperature part can be reduced independently of the electric power generation amount of a battery part at the time of a driving | operation of a SOFC bundle. In addition, the degree of temperature reduction can be adjusted by adjusting the flow rate of the hydrogen production fuel to the fuel reformer B depending on the temperature of the high temperature part of the battery. By controlling the amount of hydrogen produced by the mass device B, the degree of temperature reduction in the high temperature part of the battery can be controlled.

  The raw fuel in the fuel supply system to the SOFC in the present invention, and the fuel reformed by a hydrogen reforming fuel reformer different from that are hydrocarbon systems such as methane, ethane, ethylene, propane, and butane. Gas fuel, gas mixture such as two or more of these, natural gas, petroleum gas, coal gas, generator gas, water gas, blast furnace gas, petroleum cracked gas, etc., carbonization of gasoline, light oil, kerosene, diesel oil, etc. Hydrogen-based liquid fuels, ether-based liquid fuels such as dimethyl ether, alcohol-based liquid fuels such as methanol and ethanol, biomass fuels obtained by gasification of various organic wastes such as methane fermentation and wood chips, as well as those gaseous fuels, Two or more mixed fuels of liquid fuel, that is, two or more kinds of gaseous fuel, two or more kinds of fuel such as gasoline and ethanol Mixed fuel body the fuel, also used a mixed fuel of the at least one liquid fuel and at least one gaseous fuel.

Diagram explaining the “battery high temperature range” that occurs during operation of the SOFC stack Illustration explaining the “battery high temperature range” that occurs when operating multiple SOFC stacks The figure explaining the aspect which suppresses the temperature rise of a battery using the endothermic reaction at the time of reforming raw material fuel and air quantity control in the case of arranging a plurality of SOFC stacks (prior art) The figure explaining the aspect which suppresses the temperature rise of a battery using the endothermic reaction at the time of reforming the fuel supplied to a SOFC system (prior art) Figure showing the aspect of producing high purity hydrogen by purifying SOFC anode off gas (No. 942) Diagram showing the production of high purity hydrogen by refining SOFC anode off gas (No. 714) The figure explaining the aspect 1 of this invention The figure explaining aspect 2 of this invention The figure explaining aspect 3 of this invention The figure explaining aspect 4 of this invention The figure explaining aspect 4 of this invention

Explanation of symbols

  1-4 SOFC stack

Claims (7)

  In a solid oxide fuel cell system, a fuel reformer for hydrogen production, separate from the fuel supply system to the solid oxide fuel cell, is placed near the solid oxide fuel cell that is in the high temperature range during operation. A temperature reduction method for the high temperature region of the solid oxide fuel cell system, wherein during the operation, the temperature in the high temperature region is reduced using an endothermic reaction in the fuel reformer.   2. The battery of the solid oxide fuel cell system according to claim 1, wherein the degree of temperature reduction in the high temperature region is controlled by adjusting the amount of hydrogen produced by the fuel reformer depending on the temperature in the high temperature region. Temperature reduction method for high temperature range.   3. The solid oxide fuel cell system according to claim 1, wherein the fuel cell main body of the solid oxide fuel cell system is a flat, cylindrical or horizontal stripe solid oxide fuel cell. A method for reducing the temperature of high-temperature batteries.   In a solid oxide fuel cell system in which a plurality of solid oxide fuel cell stacks are juxtaposed, among the plurality of solid oxide fuel cell stacks, a solid oxide fuel cell stack that becomes a high temperature region during operation thereof Near the fuel cell stack, a hydrogen reforming fuel reformer separate from the fuel supply system to each solid oxide fuel cell stack is disposed, and during operation, the endothermic reaction in the fuel reformer is utilized to utilize the endothermic reaction. A temperature reduction device for a high temperature region of a solid oxide fuel cell system, characterized in that the temperature in the high temperature range is reduced.   In a solid oxide fuel cell system in which a plurality of solid oxide fuel cell stacks are juxtaposed, among the plurality of solid oxide fuel cell stacks, a solid oxide fuel cell stack that becomes a high temperature region during operation thereof In between, a hydrogen reforming fuel reformer separate from the fuel supply system to each solid oxide fuel cell stack is disposed, and during operation, the endothermic reaction in the fuel reformer is utilized to utilize the high temperature A temperature reduction device for a high temperature region of a solid oxide fuel cell system, characterized in that the temperature of the region is reduced.   In the solid oxide fuel cell system in which a plurality of cylindrical solid oxide fuel cells are arranged, a cylindrical solid that becomes a high temperature region during operation among the plurality of cylindrical solid oxide fuel cells. A fuel reformer for hydrogen production, which is different from the fuel supply system to each cylindrical solid oxide fuel cell, is arranged between the oxide fuel cells, and in the operation, An apparatus for reducing the temperature in the high temperature range of a solid oxide fuel cell system, wherein the temperature in the high temperature range is reduced using an endothermic reaction. 7. The degree of temperature reduction in the high temperature region is controlled by adjusting the amount of hydrogen produced by the fuel reformer according to the temperature in the high temperature region according to any one of claims 4 to 6. A temperature reduction device for a high temperature region of a solid oxide fuel cell system.

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