WO2007077791A1

WO2007077791A1 - Indirect internal reforming solid oxide fuel cell

Info

Publication number: WO2007077791A1
Application number: PCT/JP2006/325772
Authority: WO
Inventors: Yasushi Mizuno; Susumu Hatada; Iwao Anzai
Original assignee: Nippon Oil Corporation
Priority date: 2005-12-28
Filing date: 2006-12-25
Publication date: 2007-07-12
Also published as: TW200746537A; JP2007179885A; JP5216190B2

Abstract

This invention provides an indirect internal reforming solid oxide fuel cell using kerosine as a reforming raw material, which, even when operating conditions have been varied, can be stably operated without a deterioration in efficiency. The indirect internal reforming solid oxide fuel cell comprises a reformer capable of reforming kerosine, a solid oxide fuel cell using a reformed gas obtained from the reformer as a fuel, and a burner for heating the reformer. The reformer has a double pipe structure comprising an outer pipe and an inner pipe. A reforming catalyst, which can reform kerosine through steam reforming, is packed in a space between the outer pipe and the inner pipe. The burner is connected to one end of the inner pipe. The reformer is disposed at a position that the outer surface of the outer pipe receives thermal radiation from the solid oxide fuel cell.

Description

Indirect internal reforming type solid oxide fuel cell

Technical field

The present invention relates to a solid oxide fuel cell, and more particularly to an indirect internal reforming solid oxide fuel cell having a reformer in the vicinity of the fuel cell.

Background art

[0002] In a solid oxide fuel cell (hereinafter referred to as SOFC in some cases), reforming raw materials such as kerosene are reformed to form a reformed gas containing hydrogen and reformed gas. Is being supplied to SOFC as fuel. As the reforming reaction, steam reforming reaction with endotherm is mainly used.

[0003] Since the operating temperature of SOFC is high and close to the reforming temperature of the reforming raw material fuel, an indirect internal reforming that uses SOFC heat for reforming by placing a reformer at a position that receives heat radiation from SOFC There is a type SOFC (see Patent Document 1).

Patent Document 1: Japanese Patent Laid-Open No. 2002-358997

Disclosure of the invention

Problems to be solved by the invention

[0004] However, when a higher-order hydrocarbon such as kerosene is used as a reforming raw material, if a hydrocarbon component that has not been reformed is supplied to a solid oxide fuel cell having a high operating temperature, it is operated by carbon deposition. May be impaired. Therefore, higher hydrocarbons like kerosene

It is desirable to completely convert the compound to C1 compound (compound with 1 carbon atom).

[0005] During steady operation that can sufficiently receive fuel cell exhaust heat, a high conversion rate can be maintained if a sufficient heat receiving area is given to the reformer by system design. However, the fuel cell is subject to load fluctuations, disturbances, etc. When the amount of exhaust heat is reduced, if the amount of reforming of the reforming raw material is suddenly increased, the amount of heat necessary for reforming may be insufficient, causing a reduction in the conversion rate during reforming. is there. At this time, it is also possible to suppress the decrease in the conversion rate by reducing the fuel utilization rate of the fuel cell to increase the calorific value of the anode off gas and heating the reformer with the combustion heat of the anode off gas. In this case, however, the reformed fuel is burned once. Since the heat is supplied, the efficiency is greatly reduced.

[0006] An object of the present invention is to stably operate an indirect internal reforming solid oxide fuel cell using kerosene as a reforming raw material without lowering efficiency even when operating conditions fluctuate. An indirect internal reforming type solid oxide fuel cell that can be manufactured is provided.

Means for solving the problem

[0007] According to the present invention, a reformer capable of reforming kerosene, a solid oxide fuel cell using a reformed gas obtained from the reformer as a fuel, and a panner for heating the reformer The reformer has a double pipe structure consisting of an outer pipe and an inner pipe,

A space between the outer tube and the inner tube is filled with a reforming catalyst capable of steam reforming kerosene, and the panner is connected to one end of the inner tube,

The reformer is arranged at a position where the outer surface of the outer tube receives solid oxide fuel cell power thermal radiation.

An indirect internal reforming solid oxide fuel cell is provided.

[0008] In the indirect internal reforming solid oxide fuel cell, the reformer may have a plurality of the double-pipe structures.

[0009] The reforming catalyst may include a reforming catalyst having kerosene oxidation activity.

The invention's effect

[0010] According to the present invention, an indirect internal reforming solid oxide fuel cell using kerosene as a reforming raw material can be stably operated without lowering efficiency even when operating conditions fluctuate. An indirect internal reforming solid oxide fuel cell is provided.

Brief Description of Drawings

FIG. 1 is a schematic diagram showing an example of an indirect internal reforming SOFC of the present invention.

Explanation of symbols

[0012] 1: reformer

la: outer tube

lb: Inner pipe

3: Solid oxide fuel cell 3a: Anode

3b: Solid oxide electrolyte

3c: Power Sword

4: Pana

5: Reforming catalyst

o: Valley device

BEST MODE FOR CARRYING OUT THE INVENTION

In the reformer, a reformed gas that is a gas containing hydrogen is produced from kerosene that is a reforming raw material by a steam reforming reaction. Although partial oxidation reforming reaction may be accompanied at this time, steam reforming is made dominant from the viewpoint of efficiently producing hydrogen. Therefore, in the reformer, the reaction becomes endothermic in overall.

[0014] The reformer has a double tube structure formed of an outer tube and an inner tube. Therefore, the reformer has two spaces, a space between the outer tube and the inner tube (hereinafter, referred to as an annular portion) and a space inside the inner tube, which are separated from each other.

[0015] The annular portion is filled with a reforming catalyst capable of reforming kerosene. As the reforming catalyst, a water steam reforming catalyst or an autothermal reforming catalyst (a catalyst having steam reforming ability and partial oxidation reforming ability) can be used. A known catalytic force capable of steam reforming or autothermal reforming of kerosene to be used can be appropriately selected and employed.

[0016] Preferably, the reforming catalyst includes a reforming catalyst having kerosene oxidation activity. Kerosene oxidation activity means the ability to generate heat by oxidizing kerosene with oxygen on the catalyst. By filling the reforming section with a catalyst having kerosene oxidation activity, heat is directly generated on the catalyst, and the time until the reforming catalyst reaches a temperature suitable for reforming can be shortened.

[0017] A panner is connected to one end of the inner tube. A panner can be attached to the inner tube itself. Alternatively, the inner pipe and the burner may be arranged apart from each other and connected between them by a conduit to guide the burner combustion gas to the inner pipe. When there are multiple double pipes, one perner may be connected to the inner pipe of each double pipe, but the combustion gas of one parner may be branched and supplied to multiple inner pipes. ,.

[0018] The panner is appropriately selected from known panners capable of combusting the panner fuel to be used. It can be done.

[0019] It is preferable to use kerosene used as a reforming raw material as the fuel for the PANA. This is because it is not necessary to prepare a separate fuel. However, other fuels can be used.

[0020] As the SOFC, various shapes such as a flat plate shape and a cylindrical shape can be appropriately selected and employed. SOFC may be a single cell! /, But for practical use, a stack in which a plurality of single cells are arranged is preferably used. In this case, there may be one or more stacks. SOFC, reformer and panner can be accommodated in a container such as a can and modularized.

[0021] The reformer is arranged at a position where direct heat transfer to the outer surface of the SOFC force outer tube is possible. It is preferred that substantially no shielding be placed between the reformer and the SOFC. In addition, it is preferable to shorten the distance between the reformer and the SOFC as much as possible. For example, multiple double tubes can be placed around the SOFC stack.

[0022] In the indirect internal reforming SOFC of the present invention, the reforming catalyst can receive the exhaust heat of SOFC from the outer pipe surface, and can receive the heat of the Pana combustion gas flowing in the inner pipe. It becomes.

[0023] If the heat supply to the reformer is insufficient with only the exhaust heat of the fuel cell due to disturbance or a rapid increase in the reforming amount, combustion may be performed with the PANANER, and the heat shortage may be compensated by the heat of the PANANA combustion gas. Therefore, the solid oxide fuel cell can be stably operated without reducing the efficiency. If the heat required for reforming can be provided with only SOFC exhaust heat, the burner does not have to be burned. The necessity of Pana combustion can be judged by the reforming catalyst outlet temperature. In order to complete the steam reforming reaction of kerosene, the reforming catalyst outlet temperature is preferably 580 ° C or higher, more preferably 620 ° C or higher, and further preferably 650 ° C or higher. In order to suppress thermal degradation of the reforming catalyst, the temperature is preferably 850 ° C or lower, more preferably 800 ° C or lower, and further preferably 750 ° C or lower.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto. FIG. 1 is a schematic diagram showing an embodiment of the internal reforming SOFC of the present invention.

[0025] The reformer 1 has an outer pipe la and an inner pipe lb, and a panner 4 is connected to the inner pipe. With outer tube A reforming catalyst 5 is filled in the annular portion between the inner pipe and the inner pipe. The reformer and SOFC3 are placed close to each other and there is a gap between them (no shield is placed).

[0026] Steam and vaporized kerosene are supplied to the annular portion, and the kerosene is steam-reformed to become hydrogen-containing gas (reformed gas), which is supplied to the SOFC anode (fuel electrode) 3a. The steam reforming reaction is an endothermic reaction. On the other hand, oxygen-containing gas (air here) is supplied to the SOFC power sword (air electrode) 3c. The SOFC generates heat during power generation, and the heat is radiated from the SOFC to the outer surface of the outer tube. In this way, the SOFC exhaust heat is used to absorb the reforming reaction. Note that 3b is an electrolyte with solid acidity.

[0027] The reformer and the SOFC are accommodated in a container 6. The panner is provided through the wall of the container.

[0028] Gas coupling and the like are appropriately performed using piping or the like.

[0029] If the heat required for the reforming reaction cannot be achieved by SOFC exhaust heat alone, such as when the operating conditions fluctuate, kerosene is burned with oxygen-containing gas (here, air) in PANA-4, and Combustion gas can be flowed through the inner pipe to make up for the shortage. The combustion exhaust discharged from the inner pipe force is further used as necessary to be discharged to the outside.

[0030] For example, the temperature of the reformer catalyst can be continuously monitored and ONZOFF control can be performed so that the temperature becomes a predetermined value or higher.

[0031] Each supply gas is appropriately preheated as necessary and then supplied to the reformer or SOFC.

Industrial applicability

[0032] The indirect internal reforming SOFC of the present invention can be used for, for example, a stationary or mobile power generation system, and a cogeneration system.

Claims

The scope of the claims

[1] A reformer capable of reforming kerosene, a solid oxide fuel cell using the reformed gas obtained from the reformer as fuel, and a panner for heating the reformer ,

The reformer has a double pipe structure consisting of an outer pipe and an inner pipe,

Indirect internal reforming type solid oxide fuel cell.

2. The indirect internal reforming solid oxide fuel cell according to claim 1, wherein the reformer has a plurality of the double pipe structures.

3. The indirect internal reforming solid oxide fuel cell according to claim 1 or 2, wherein the reforming catalyst includes a reforming catalyst having kerosene oxidation activity.