WO2007077780A1

WO2007077780A1 - Indirect internal reforming solid oxide fuel cell

Info

Publication number: WO2007077780A1
Application number: PCT/JP2006/325734
Authority: WO
Inventors: Yasushi Mizuno; 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: JP2007179884A; TW200740019A; JP5007045B2

Abstract

This invention provides an indirect internal reforming solid oxide fuel cell using kerosine as a reforming raw material, which can be stably operated without an abnormal deterioration in a reforming catalyst and 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 is disposed between the solid oxide fuel cell and the burner and comprises first and second reforming parts in communication with each other. With respect to the flow of the reformed gas, the first reforming part is located on the upstream side, and the second reforming part is located on the downstream side. The second reforming part is disposed at a position that receives thermal radiation from the solid oxide fuel cell and blocks thermal radiation from the solid oxide fuel cell to the first reforming part.

Description

Specification

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] When the entire reformer receives radiant heat transfer from the solid oxide fuel cell, when the solid oxide fuel cell reaches a steady state, the reformer almost uniformly reaches the vicinity of the reforming material inlet. Since it is heated and the temperature is high, carbon may be deposited on the catalyst near the reforming raw material inlet, causing abnormal deterioration of the catalyst.

[0007] An object of the present invention is to operate stably in an indirect internal reforming solid oxide fuel cell using kerosene as a reforming raw material without abnormally degrading the reforming catalyst or lowering the efficiency. An indirect internal reforming type solid oxide fuel cell capable of performing

[0008] 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 is disposed between the solid oxide fuel cell and the panner,

The reformer has a first reforming section and a second reforming section communicating with each other;

With respect to the flow of the reformed gas, the first reforming section is located upstream and the second reforming section is located downstream, and the second reforming section is heated by the solid oxide fuel cell power. There is provided an indirect internal reforming solid oxide fuel cell that is disposed at a position that receives radiation and blocks heat radiation from the solid oxide fuel cell to the first reforming section.

[0009] The indirect internal reforming type solid oxide fuel cell may further include a reforming material preheater directly connected to the reformer inlet so as to be integrated with the reformer.

[0010] The reforming catalyst filled in the first reforming section and the second reforming section may include a reforming catalyst having kerosene oxidation activity.

The invention's effect

[0011] According to the present invention, in an indirect internal reforming solid oxide fuel cell using kerosene as a reforming raw material, the reforming catalyst can be stably operated without deteriorating abnormally or reducing efficiency. 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. FIG. 2 is a schematic view showing another example of the indirect internal reforming SOFC of the present invention. Explanation of symbols

[0013] 1: Pana

2: Reformer

2a: First reforming section

2b: Second reforming section

3: SOFC

3a: Anode electrode

3b: Solid oxide electrolyte

3c: force sword electrode

4: SOFC stack

5: Reforming raw material preheater

o: Valley device

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] In the reformer, a reformed gas, which is a gas containing hydrogen, is produced from kerosene, which 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.

[0015] The reformer has a first reforming section and a second reforming section that communicate with each other. With respect to the flow of the reformed gas, the first reforming section is located on the upstream side and the second reforming section is located on the downstream side. That is, the reforming material is supplied to the first reforming section, and the gas exiting the first reforming section flows into the second reforming section.

[0016] Both the first reforming section and the second reforming section are filled with a reforming catalyst capable of reforming kerosene. As the reforming catalyst, a steam reforming catalyst or an autothermal reforming catalyst (a catalyst having a steam reforming ability and a partial acidity reforming ability) can be used. The kerosene to be used can be selected and employed as appropriate with known catalytic power capable of steam reforming or autothermal reforming.

[0017] The reforming catalyst filled in the first reforming section and the second reforming section has kerosene oxidation activity. It is preferable to include a reforming catalyst. Kerosene oxidation activity refers to the ability of kerosene to react with oxygen and oxygen on the catalyst to generate heat. By charging the reforming section with a catalyst having 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.

[0018] The indirect internal reforming SOFC of the present invention includes a reformer and a SOFC in addition to a SOFC for heating the reformer. As the burner, a known burner capable of burning the burner fuel to be used can be appropriately selected and used.

[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 disposed between the SOFC and the PANA. That is, both the first reforming section and the second reforming section are arranged between the SOFC and the PANA.

[0022] The second reforming section is disposed at a position where direct radiation heat transfer to the SOFC force second reforming section is possible. The direct radiant heat transfer to the first reforming section is blocked by the second reforming section.

[0023] In the indirect internal reforming SOFC of the present invention, even if heat supply is insufficient only by exhaust heat from the fuel cell due to disturbance or rapid increase in reforming amount, the heat shortage can be compensated by the combustion heat of the PANA. Stable operation is possible without reducing efficiency. If the heat required for reforming can be provided with only SOFC exhaust heat, the burner does not need to be burned.

[0024] Furthermore, since the second reforming section can receive radiant heat of SOFC force, the first reforming section blocks the SOFC force radiant heat by the second reforming section, so the first reforming section It is easy to make the temperature lower than that of the second reforming part. Therefore, the inlet side of the reformer can be made lower in temperature, thereby making it easier to suppress carbon deposition.

[0025] Further, the reforming material preheater is directly connected to the reformer inlet so as to be integrated with the reformer. Can do. The reforming raw material preheater refers to a heat exchanger that vaporizes, preheats and mixes raw materials for obtaining reformed gas containing hydrogen, that is, kerosene and water. By directly connecting the preheater so as to be united with the first reforming section, the preheater can be efficiently warmed by heat transfer from the reforming section. In addition, it becomes easy to lower the reforming section inlet to a temperature at which the reforming catalyst does not deteriorate abnormally by heat transfer from the reforming section to the preheater.

[0026] The temperature of the preheater is preferably 150 ° C or higher, more preferably 200 ° C or higher, and even more preferably 250 ° C or higher so that kerosene can be vaporized stably. In order to prevent carbon deposition in the preheater, the temperature is preferably 500 ° C or lower, more preferably 450 ° C or lower, and further preferably 400 ° C or lower.

[0027] The inlet temperature of the first reforming section is preferably 300 ° C or higher, more preferably 350 ° C or higher, in order to prevent recondensation of the gasified raw material and operate the catalyst effectively. The temperature is preferably 400 ° C or higher. In order to prevent carbon deposition at the catalyst inlet, the temperature is preferably 550 ° C or lower, more preferably 500 ° C or lower, and further preferably 450 ° C or lower.

[0028] In order to efficiently transfer heat between the reforming raw material preheater and the first reforming section, a structure in which the reforming raw material preheater and the first reforming section are integrated with each other is desirable.

[0029] For example, the interior of one container is partitioned to form two adjacent regions, and a reforming material preheater and a reformer are arranged in each region, thereby reforming at the reformer inlet. The raw material preheater can be directly connected to the reformer.

Example

[Example 1]

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 internal reforming SOFC of this example.

[0031] The indirect internal reforming SOFC of the present embodiment includes a container 1, a reformer 2, and a SOFC stack 4 in which a plurality of cylindrical SOFCs 3 are arranged.

[0032] Air and kerosene can be supplied to the burner 1 for combustion, and kerosene is burned here. The surface burner which can take a large combustion surface where the ratio of radiant heat is high is preferable for the panner. As the surface combustion burner, for example, a burner using a ceramic plate or a metal mat on the combustion surface can be used. [0033] Kerosene and water are supplied to the reforming raw material preheater 5, both of which are vaporized and mixed sufficiently.

[0034] Kerosene and water vaporized by the reforming raw material preheater are supplied to the reformer 2 to perform steam reforming.

[0035] The reformer stacks two rectangular parallelepiped boxes for forming a gas flow path, and provides a gas supply port at the flow path end of the first box (on the right side in FIG. 1). The two boxes communicate with each other at the end of the flow path on the opposite side (left side of the page in FIG. 1), and the flow path end opposite to the communication end of the second box (that is, the gas supply of the first box) The same end as the end where the port is provided (the right side of the paper in Fig. 1) is provided with a gas discharge port, and the first and second boxes are filled with a steam reforming catalyst capable of reforming kerosene. Has the structure. The part of the first box filled with the reforming catalyst is the first reforming part 2a, and the part of the second box filled with the reforming catalyst is the second reforming part 2b. That is, the reformer has a structure in which the internal gas flow is turned back.

[0036] Further, the reforming raw material preheater 5 and the first reforming section 2a are provided by dividing the inside of the first box. Thus, a structure in which the reforming raw material preheater 5 and the first reforming part 2a are integrated and the reforming raw material preheater 5 is directly connected to the first reforming part 2a is obtained.

[0037] In addition to the box shape, for example, circular tubes may be arranged in a plane with substantially no gap, and folded to form a reformer having first and second reforming portions. it can.

[0038] The reformer is arranged between the SOFC and the burner with the first reforming section on the Pana side and the second reforming section on the SOFC side. The wall force of the second reforming part can also receive the exhaust heat of SOFC by radiation, and can receive the combustion heat of the burner from the wall of the first reforming part.

[0039] Kerosene is reformed in a reformer to form a reformed gas containing hydrogen, which is supplied to the anode electrode 3a of the SOFC. On the other hand, an oxygen-containing gas (air here) is supplied to the force sword electrode 3c. As the power is generated, the SOFC generates heat, and the heat is radiated from the SOFC to the second reforming section. In this way, the SOFC exhaust heat is used for the endotherm of the reforming reaction. At this time, the temperature of the first reforming section becomes lower than the temperature of the second reforming section because the second reforming section blocks the radiant heat transfer to the SO FC force first reforming section. .

[0040] Note that 3b is an electrolyte that also has solid acidity. Gas exchange, etc. will be performed using piping etc. as appropriate. [0041] If the heat required for the reforming reaction cannot be achieved with SOFC exhaust heat alone, such as when operating conditions fluctuate, kerosene is burned with oxygen-containing gas (here, air) in Pana 1, and Combustion heat can be applied to the reformer to make up for the shortage. The combustion exhaust gas is further used as needed and discharged to the outside world.

[0042] 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 more.

[0043] Each supply gas is appropriately preheated as necessary and then supplied to the reformer or SOFC.

[Example 2]

FIG. 2 is a schematic diagram showing the internal reforming SOFC of this example. In Example 1, the inner side of the cylindrical S OFC is an anode and the outer side is a force sword. In this example, the inner side is a force sword and the outer side is an anode. As a result, the arrangement of gas conduits is different from that in Example 1. Except this, it is the same as the first embodiment, and the same effect as the first embodiment is obtained. Industrial applicability

[0045] 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 is disposed between the solid oxide fuel cell and the panner;

With respect to the flow of the reformed gas, the first reforming section is located upstream and the second reforming section is located downstream, and the second reforming section is heated by the solid oxide fuel cell power. Where radiation is received

An indirect internal reforming solid oxide fuel cell that is disposed at a position that blocks heat radiation from the solid oxide fuel cell to the first reforming section.

2. The indirect internal reforming solid oxide fuel cell according to claim 1, further comprising a reforming material preheater directly connected to the reformer inlet so as to be integrated with the reformer.

[3] The indirect internal reforming solid oxide according to claim 1 or 2, wherein the reforming catalyst filled in the first reforming section and the second reforming section includes a reforming catalyst having kerosene oxidation activity. Fuel cell.