JP5436746B2 - Starting method of solid oxide fuel cell module - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for starting a solid oxide fuel cell module, and more particularly to a method for starting a solid oxide fuel cell module that can be started quickly and in which carbon or the like is not deposited on fuel cells at the time of startup. It is about.

  Generally, since the operating temperature of a solid oxide fuel cell is as high as 600 to 1000 ° C., it is necessary to heat the fuel cell to near the operating temperature at the time of startup. Conventional solid oxide fuel cells use city gas as fuel for fuel cells. At the time of start-up, the city gas is directly burned in the vicinity of the fuel cell and the fuel cell is heated. (See Patent Document 1). Here, since the main component of city gas is methane, the amount of unburned carbon deposited on the fuel cells is small. However, when kerosene with a large carbon number is selected as the fuel for the fuel cell and the fuel for the fuel cell with a large carbon number is directly burned in the vicinity of the fuel cell, a large amount of unburned carbon is deposited on the surface of the fuel cell. there's a possibility that.

  Conventionally, a cylindrical fuel cell is known, but it takes time to heat, and when the fuel cell stack is heated by burning the fuel for the fuel cell in the immediate vicinity of the fuel cell stack, the carbide is not completely burned. Etc. were deposited on the surface of the fuel cell stack.

JP 2004-207007 A

Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to start up quickly, and to start up a solid oxide fuel cell module in which carbon or the like is not deposited on the fuel cell at the time of startup. Is to provide.

  As a result of intensive studies to achieve the above object, the present inventors have provided a catalytic combustion section inside a solid oxide fuel cell module, and used for the solid oxide fuel cell module in the catalytic combustion section at startup Fuel fuel (fuel cell fuel) is catalytically combusted, the catalytic combustion gas is circulated in the vicinity of the fuel cell stack, and the temperature is raised to a temperature closer to the operating temperature of the fuel cell stack, thereby quickly starting the fuel cell stack In addition, it has been found that carbon or the like can be prevented from precipitating in the fuel cell stack by burning the fuel cell fuel in the catalytic combustion section, and the present invention has been completed.

That is, the method for starting a solid oxide fuel cell module according to the present invention is a method for starting a solid oxide fuel cell module comprising a solid oxide fuel cell stack, a catalytic combustion section, and a catalytic combustion exhaust gas channel. ,
At least a part of the catalyst combustion part is filled with a combustion catalyst,
At the time of start-up, a catalytic combustion exhaust gas generated by a combustion reaction by bringing a mixed gas of an oxidizing gas and a fuel for a fuel cell, which is a hydrocarbon or an aliphatic alcohol, into contact with the combustion catalyst in the catalyst combustion section and burning in the catalyst combustion section Is transferred to the solid oxide fuel cell stack by using the catalytic combustion exhaust gas flowing through the catalytic combustion exhaust gas channel as a medium. the preheated,
The solid oxide fuel cell stack is not exposed to the catalytic combustion exhaust gas .

In starting the solid oxide fuel cell module of the present invention, as the fuel for a fuel cell, gas oil, naphtha and kerosene are preferred.

  According to the present invention, a catalyst combustion section is provided inside a solid oxide fuel cell module, and at the time of start-up, the fuel used for the solid oxide fuel cell is catalytically combusted at the catalyst combustion section, and the catalyst combustion gas is converted into a fuel cell. By circulating in the vicinity of the stack and raising the temperature to a temperature closer to the operating temperature of the fuel cell stack, it becomes possible to start the fuel cell stack quickly, and the fuel for fuel cell combustion is performed in the catalytic combustion section. Thus, it is possible to prevent carbon or the like from being deposited on the fuel cell stack.

Hereinafter, the solid oxide fuel cell module of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view of an example of the solid oxide fuel cell module of the present invention. The illustrated solid oxide fuel cell module 1 includes a solid oxide fuel cell (SOFC) stack 2 and a catalytic combustion unit 3, and the catalytic combustion unit 3 burns the fuel for the fuel cell, thereby solid oxide fuel cell module 1. The physical fuel cell stack 2 can be preheated.

  In FIG. 1, an oxidizing gas supply line 4 </ b> A and a fuel cell fuel supply line 5 </ b> A are connected to the catalytic combustion unit 3, and a combustion catalyst 6 is provided at least in part of the catalytic combustion unit 3. Filled. In FIG. 1, an oxidizing gas supply line 4 </ b> A and a fuel cell fuel supply line 5 </ b> A are directly connected to the catalytic combustion unit 3, and the oxidizing gas and the fuel cell fuel are mixed in the catalytic combustion unit 3. However, it is also possible to mix the oxidizing gas and the fuel cell fuel before introducing them into the catalytic combustion unit 3. In this case, the oxidizing gas supply line and the fuel cell fuel supply line are connected to the catalytic combustion unit 3. What is necessary is just to connect outside and to connect the supply line of mixed gas to the catalyst combustion part 3 from this connection part.

  On the other hand, in FIG. 1, an oxidizing gas supply line 4 </ b> B and a power generation fuel supply line 5 </ b> B are connected to the solid oxide fuel cell stack 2, and in the vicinity of the solid oxide fuel cell stack 2. Is provided with a catalytic combustion exhaust gas flow path 7.

  In FIG. 1, the oxidizing gas and the fuel for fuel supplied to the catalytic combustion unit 3 through the oxidizing gas supply line 4 </ b> A and the fuel cell fuel supply line 5 </ b> A come into contact with the combustion catalyst 6 in the catalytic combustion unit 3. Burns and generates combustion heat. Further, the catalytic combustion exhaust gas generated by the combustion reaction flows through the catalytic combustion exhaust gas passage 7 while carrying combustion heat, and at the same time, the solid oxide fuel cell stack 2 in the vicinity of the catalytic combustion exhaust gas passage 7 is heated.

As described above, since the operating temperature of the solid oxide fuel cell stack 2 is as high as 600 to 1000 ° C., the solid oxide fuel cell stack 2 needs to be preheated to the vicinity of the operating temperature at startup. When the battery module is started, as shown in FIG. 1, the fuel for the fuel cell is burned in the catalytic combustion unit 3 and the generated combustion heat is transmitted to the solid oxide fuel cell stack 2 using the catalytic combustion exhaust gas as a medium. By heating the solid oxide fuel cell stack 2, it can be easily preheated to near the operating temperature.

  In addition, when the fuel for the fuel cell is directly burned in the vicinity of the fuel cell stack as in the case of the conventional solid oxide fuel cell, carbon may be deposited on the surface of the battery cell of the fuel cell stack. When a large fuel cell fuel was used, carbon deposition on the battery cell surface was remarkable. However, in the solid oxide fuel cell module of the present invention, the fuel cell fuel was burned in the vicinity of the fuel cell stack. Since it does not carry out directly but in the catalyst combustion part 3, it can prevent reliably that carbon etc. precipitate on the battery cell surface.

  The solid oxide fuel cell stack 2 constituting the solid oxide fuel cell module of the present invention is not particularly limited, and a solid oxide fuel cell stack having a known structure can be adopted. In general, the solid oxide fuel cell stack is often configured by stacking a plurality of battery cells.

  Further, the catalyst combustion section 3 constituting the solid oxide fuel cell module of the present invention is not particularly limited as long as at least a part thereof can be filled with a combustion catalyst, and can have any shape, size, or the like. Moreover, the material of the catalyst combustion part 3 is not specifically limited, Various materials, such as stainless steel, can be used. Further, as the combustion catalyst filled in the catalyst combustion section 3, any known oxidation catalyst can be appropriately selected as long as the fuel for the fuel cell of the solid oxide fuel cell can be combusted. For this, a catalyst in which Pt, Pd or the like that hardly deteriorates at a high temperature is supported on a carrier such as alumina or silica is preferable.

Fuel for fuel cell using the solid oxide fuel cell module of the present invention is a hydrocarbon or an aliphatic alcohol. Here, as the hydrocarbon, a gas such as methane, ethane, propane, or butane, or a liquid fuel such as light oil, gasoline, naphtha, or kerosene can be used. On the other hand, as the aliphatic alcohol, methanol, ethanol, or the like is used. be able to. Among these, in the present invention, from the viewpoint of fuel cost, hydrocarbons having a large carbon number, more specifically, light oil, naphtha, and kerosene are preferable, and kerosene is particularly preferable.

  Here, when a hydrocarbon or aliphatic alcohol having a large carbon number is used as the fuel cell fuel, when the fuel cell fuel is directly introduced into the anode electrode of the solid oxide fuel cell stack 2 together with water vapor, the C2 + component (carbon Since the carbon deposition on the anode electrode is a concern due to the influence of the component (2 or more), after reforming the fuel cell fuel outside the solid oxide fuel cell stack 2, hydrogen is the main component. It is preferable to introduce the reformed gas (power generation fuel) to the anode electrode.

  The method for reforming the fuel cell fuel outside the solid oxide fuel cell stack 2 is not particularly limited, and a known reformer is used to mix a fuel cell fuel and water vapor, for example, , Contact with a reforming catalyst in which Ru, Ni, W, Co, Rh, Pt is supported alone or in plural on a support such as alumina, silica, zirconia, etc. Can be carried out at various temperatures.

  In the solid oxide fuel cell module of the present invention, air is generally used as the oxidizing gas introduced into the solid oxide fuel cell stack 2 and the catalytic combustion unit 3 from the viewpoint of cost. Oxygen may be used.

  Although not shown in the figure, the fuel cell fuel introduced into the catalyst combustion unit 3 is preferably supplied as a gas to the catalyst combustion unit 3 and therefore upstream of the catalyst combustion unit 3 of the fuel cell fuel supply line 5A. It is preferable to provide a heating means.

It is the schematic of an example of the solid oxide fuel cell module of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell module 2 Solid oxide fuel cell stack 3 Catalytic combustion part 4A, 4B Oxidative gas supply line 5A Fuel supply line for fuel cells 5B Fuel supply line for power generation 6 Combustion catalyst 7 Catalytic combustion exhaust gas flow path

Claims (2)

A method for starting a solid oxide fuel cell module comprising a solid oxide fuel cell stack, a catalytic combustion section, and a catalytic combustion exhaust gas channel,
At least a part of the catalyst combustion part is filled with a combustion catalyst,
At the time of start-up, a catalytic combustion exhaust gas generated by a combustion reaction by bringing a mixed gas of an oxidizing gas and a fuel for a fuel cell, which is a hydrocarbon or an aliphatic alcohol, into contact with the combustion catalyst in the catalyst combustion section and burning in the catalyst combustion section Is transferred to the solid oxide fuel cell stack by using the catalytic combustion exhaust gas flowing through the catalytic combustion exhaust gas channel as a medium. the preheated,
A solid oxide fuel cell module startup method, wherein the solid oxide fuel cell stack is not exposed to the catalytic combustion exhaust gas .   2. The method for starting a solid oxide fuel cell module according to claim 1, wherein the fuel for the fuel cell is light oil, naphtha or kerosene.

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