JPS6124168A - Fused carbonate type fuel cell device - Google Patents

Abstract

PURPOSE:To separate a reformer from a fuel cell and obtain a device easy for maintenance such as the reactivation or replacement of a catalyst and excellent in reliability with a simple structure by providing the reformer on a discharged fuel gas passage or a discharged oxidation gas passage from a fuel cell so as to give the heat of the discharged fuel gas or the discharged oxidation gas to the reformer. CONSTITUTION:The fuel mainly consisting of hydogen carbide and steam is fed to a reformer 9. The reformer 9 has a hydrogen carbide-resolving catalyst 2 in it and is provided inside an oxidation gas outlet manifold 8 and resolves hydrogen carbide by utilizing the sensible heat of the discharged oxidation gas. The fuel gas reformed by the reformer 9 to be mainly consisting of hydrogen and carbon monoxide is fed to a fuel cell laminated body 1 through a fuel gas inlet manifold 10, and the chemical energy of the fuel gas is converted into electric energy and byproduct thermal energy. In this case, the byproduct thermal energy is taken away by the oxidation gas and is heat-exchanged with the fuel gas through the outer wall of the reformer 9 inside the oxidation gas outlet manifold 8, and most of it is utilized as the reaction heat of hydrogen carbide resolution.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a molten carbonate fuel cell device.

2 is a sectional view of a conventional internal reforming type molten carbonate fuel cell device as seen from the side. In the figure, (1) indicates a plurality of fuel cells 1, such as molten carbonate fuel cells (hereinafter referred to as fuel cells) (tc), end plates (la
), separator plate (1b), catalyst holding cooling plate (1d)
The fuel cell stack 1 is, for example, a molten carbonate fuel cell stack (hereinafter referred to as a fuel cell stack).

The catalyst holding cooling plate (1d) has a hydrocarbon decomposition catalyst (2
] is maintained. Fuel is supplied to and discharged from the fuel cell stack (1) through the fuel gas inlet and outlet manifold (3). The fuel gas inlet/outlet manifold (3) is provided with an internal manifold (8a) for distributing and supplying fuel gas to the catalyst holding cooling plate (Xd). (4) is a fuel gas reversing manifold for reversing and supplying the fuel gas discharged from the catalyst holding cooling plate (1d) to the fuel cell stack (υ).

(5) is an insulating joint for electrically insulating the catalyst holding cooling plate (1d), and (6) is an insulating joint between the fuel cell stack (υ), the fuel gas inlet/outlet manifold +33, and the fuel gas reversing manifold (4). A gasket that maintains electrical insulation and airtightness of the reactant gases, which are the fuel gas and the oxidant gas.
It is. In the figure, arrows indicate the direction in which fuel or fuel gas flows.

Next, the operation will be explained. Hydrocarbon-based fuel and steam are stored in the internal manifold (8a) and insulated joints (
5) is supplied to the catalyst holding cooling plate (1d). Hydrocarbons and steam are generated by the catalytic action of the hydrocarbon decomposition catalyst (2) inside the catalyst holding cooling plate (1d) according to the following formula (υ~(3)
As shown in Figure 2, molten carbonate fuel cells (ICs) directly generate soot.
It is transformed into a fuel gas whose main components are hydrogen and carbon monoxide, which can be used as fuel.

CHn + HzO-+ Co + 8H2+4.
9.8kcae/moe -(1)m+2n CnHm + nHao →nco + -H2f21
Co+HzO→CO2+H! -9,8kca
e/moe - (3) These reactions are endothermic reactions as a whole, and the thermal energy by-produced in the fuel cell (IC) is used as reaction heat to cool the fuel cell stack (1).

The altered fuel gas reverses its flow direction inside the fuel gas inversion manifold (4) and is supplied to the fuel gas side electrode of the fuel cell (IC). Here, a molten carbonate fuel cell (1
c) is a fuel cell that operates at, for example, around 650°C, and the fuel gas side electrode and oxidant gas side electrode each have the following formula (
4) and +5), (By performing an electrochemical reaction as shown in 61, the chemical energy of hydrogen and carbon oxide is converted into electrical energy and thermal energy as a by-product.

(Fuel gas side electrode) H2+ Co: -* H,0+ c02+ 2e
-+4) CO+H20→H2+CO2-
(51 (Oxide gas measurement Cot "20z" 2e → COa
(61 As mentioned earlier, most of the by-produced thermal energy is removed as reaction heat of the hydrocarbon decomposition reaction through the catalyst holding cooling plate (1d), and the rest is removed by gas cooling using the reaction gas as a heat medium. The fuel gas consumed in the fuel cell (LC) is discharged to the outside of the system through the fuel gas inlet and outlet manifold (3). It is a stacked body in which multiple molten carbonate fuel cells (IC) that generate DC voltage are connected in series, and has a structure that prevents electrical short circuits between the molten carbonate fuel cells (LC) through an internal manifold (8a). The insulating coupling (5) is for preventing electrical short circuits through the catalyst holding cold plate (1d) and is made, for example, of a ceramic material.

In this way, the fuel gas supplied to the fuel cell (lc) needs to be reformed into a fuel gas containing hydrogen and carbon monoxide as main components that can be directly used by the fuel cell (1c) as fuel. In this conventional device, for example, an internal manifold (8a
), catalyst holding cooling plate (ld), hydrocarbon decomposition catalyst (2
) and an insulating joint (6) constitute a reformer to reform the fuel gas.

[Problems to be Solved by the Invention] In the conventional molten carbonate fuel cell device, the reformer is built into the molten carbonate fuel cell stack (1), and a plurality of fuel cells (1c) because it is provided in the flow path that distributes and supplies fuel gas.

This method requires a structure for distributing fuel gas to each catalyst holding cooling plate (ld), and requires an insulating joint (6), resulting in a complicated manifold structure. In addition, hydrocarbon decomposition catalysts (2nd, long-term sinter link
Although activity decreases due to carbon precipitation, etc., such a structure has the problem that maintenance such as regeneration and replacement is difficult.

The present invention has been made to solve these problems, and aims to provide a molten carbonate fuel cell device that has a simple structure and is easy to maintain such as catalyst regeneration and replacement.

[Means for solving problems]

A molten carbonate fuel cell device according to the present invention.

A reformer having a catalyst and reforming fuel gas, and a fuel gas reformed by the reformer being supplied thereto.

In a fuel cell that is supplied with oxidizing gas to cause an electrochemical reaction, a reformer is installed in the exhaust fuel gas flow path or exhaust oxidant gas flow path from the fuel cell, and the heat of the exhaust fuel gas or exhaust oxidant gas is removed. is supplied to the reformer.

[Operation of the means for solving the problem] In its function, the reformer in the present invention is separated from the fuel cell stack and is provided in the exhaust fuel gas flow path or the exhaust oxidant gas flow path, and is Since there is no need to distribute fuel gas to multiple fuel cells within the reformer, the structure is simple and maintenance such as regeneration and replacement of the catalyst in the reformer becomes easy.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, [υ] is a fuel cell stack 1, such as a molten carbonate fuel cell stack, which is composed of a plurality of fuel cells, such as molten carbonate fuel cells, end plates, and separator plates.

As in the conventional example, (2) is a hydrocarbon decomposition catalyst, and (6) is a gasket.

(7) is an oxidizing gas inlet manifold, and (8) is an exhaust oxidizing gas flow path, for example, an oxidizing gas outlet manifold.

The oxidizing gas outlet manifold (8) is equipped with a reformer (9) holding a hydrocarbon decomposition catalyst (2) therein.

OO is a fuel gas inlet manifold, which is connected to the outlet side of the reformer (9). Ql) is 1 in the exhaust fuel gas flow path.
For example, a fuel gas outlet manifold. In addition.

In the figure, arrow A indicates the direction in which fuel gas flows, and arrow B indicates the direction in which oxidizing gas flows.Next, the operation of such a molten carbonate fuel cell device will be explained. Hydrocarbon-based fuel and steam are supplied to the reformer (9). The reformer (9) holds a hydrocarbon decomposition catalyst [21] inside, and in this embodiment, the reformer 19) is provided inside the oxidant gas outlet manifold (8), so that the oxidant gas discharged A fuel that is reformed in the reformer (9) and whose main components are hydrogen and carbon oxide. Gas is supplied to the fuel cell stack (1) through the fuel gas inlet manifold QO, and formulas (4) to (6)
Accordingly, the chemical energy of the fuel gas is converted into electrical energy and by-product thermal energy. The thermal energy produced as a by-product at this time is carried away by the oxidizing gas,
A reformer (9) is installed inside the oxidizing gas outlet manifold (8).
), most of the heat is used as reaction heat for hydrocarbon decomposition.

In this invention, unlike the conventional example, the reformer (9) is provided independently from the fuel cell stack (1) in its function, so there is no need for an insulating joint (5) in terms of structure, and catalyst retention cooling plate (1d) and individual catalyst holding cold plate (ld)
The structure becomes much simpler, as there is no need for a complicated structure for distributing fuel gas. Furthermore, maintenance such as regeneration and replacement of the hydrocarbon decomposition catalyst (2) in the reformer (9) can be easily performed, and the reliability of the molten carbonate fuel cell device is improved.

In the above embodiment, the reformer (9) is installed inside the oxidizing gas outlet manifold (8), but it may also be installed inside the fuel gas outlet manifold (b). moreover,
Not only inside the manifold, but also in the exhaust fuel gas flow path or exhaust oxidant gas flow path from the fuel cell.

If the structure is such that the heat of the exhaust gas is applied to the reformer +93, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, a catalyst is provided.

A reformer that reformes fuel gas is supplied with fuel gas reformed by this reformer, and is equipped with a fuel cell that is supplied with oxidizing gas to cause an electrochemical reaction. By providing heat from the exhaust fuel gas or exhaust oxidant gas to the reformer by providing it in the exhaust fuel gas flow path or exhaust oxidant gas flow path from the battery, the reformer can function as a fuel cell. This has the effect of providing a highly reliable molten carbonate fuel cell device that is separated, has a simple structure, and is easy to maintain such as catalyst regeneration and replacement.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing a molten carbonate fuel cell device according to an embodiment of the present invention, and FIG. 2 is a configuration diagram showing a conventional internal reforming type molten carbonate fuel cell device. . (υ... fuel cell stack, (lc)... fuel cell,
(Phantom...catalyst, (8)...exhaust oxidizing gas flow path, (9
)...Reformer, (b)...Exhaust fuel gas flow path. In addition, in FIG. 1, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A reformer having a catalyst and reforming fuel gas, and a fuel cell to which the fuel gas reformed by the reformer is supplied and an oxidizing gas to cause an electrochemical reaction, A molten carbonate fuel cell in which the reformer is provided in an exhaust fuel gas flow path or an exhaust oxidant gas flow path from the fuel cell, and heat from the exhaust fuel gas or exhaust oxidant gas is applied to the reformer. Device.