JPH0722054A - Fuel cell power generating system - Google Patents

Abstract

PURPOSE:To provide a fuel cell power generating system capable of reducing the flow rate of cathode exhaust which is mixed in cathode gas, so reducing the piping diameter of a cathode gas circulation line, miniaturizing a high- temperature blower, and reducing the power of the high-temperature blower. CONSTITUTION:A fuel cell power generating system includes a fuel cell 20 which generates power from anode gas 2 containing hydrogen and cathode gas 3 containing oxygen and a reformer 10 which burns anode exhaust 4 from the fuel cell using part of cathode exhaust 7 and reforms fuel gas 1 into anode gas by the heat of the burning. The fuel cell 20 has a built-in fuel preheater 28 for the indirect heating of the fuel gas 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell power generator, and more particularly to a fuel cell power generator using a molten carbonate fuel cell.

[0002]

2. Description of the Related Art Molten carbonate fuel cells have characteristics that conventional power generators do not have, such as high efficiency and little impact on the environment, and they are attracting attention as a power generation system following hydropower, thermal power, and nuclear power. Is currently being researched and developed all over the world. In particular, in a power generation facility using a molten carbonate fuel cell using natural gas as a fuel, a reformer 10 for reforming a fuel gas 1 such as natural gas into an anode gas 2 containing hydrogen as shown in FIG. A fuel cell 20 for generating power from an anode gas 2 and a cathode gas 3 containing oxygen is generally provided, and the anode gas produced by the reformer is supplied to the fuel cell, and most of it (in the fuel cell) (For example, 80%), the combustion chamber C of the reformer 10 is used as the anode exhaust gas 4.
supplied to the o. The fuel gas 1 is preheated by the fuel preheater 11 and enters the reforming chamber Re of the reformer. In the reformer, combustible components (hydrogen, carbon monoxide, methane, etc.) in the anode exhaust gas are burned in the combustion chamber, and the high-temperature combustion gas heats the reforming chamber Re to reform the fuel flowing inside. The combustion exhaust gas 5 that has exited the reforming chamber is subjected to heat recovery in the air preheater 32, moisture removed in the condenser 33 and the steam separator 34, and air pressurized in the turbine compressor (power recovery device 40). 6 is mixed, and this mixed gas is heated by the air preheater 32 and merges with the cathode gas 3. As a result, carbon dioxide generated on the anode side of the cell enters the cathode gas 3 for the fuel cell via the combustion exhaust gas 5, and supplies carbon dioxide required for the cathode reaction of the fuel cell to the cathode side C. A part of the cathode gas 3 reacts in the fuel cell to become the cathode exhaust gas 7,
A part thereof is recirculated to the cathode inlet side, a part is supplied to the combustion chamber Co of the reformer 10 to burn the anode exhaust gas 4, and the remaining part is supplied to the power recovery device 40 to recover the pressure and outside the system. Is discharged to. In the figure, reference numeral 22 is a fuel cell storage container, and 8 is a purge gas supplied to the storage container.

[0003]

In the fuel cell 20, a large amount of heat is generated by the reaction. Therefore, the conventional fuel cell power generator has a cathode gas circulation line 26 equipped with a high temperature blower 24 and a gas cooler (not shown), and cools a part of the cathode exhaust gas 7 to mix it with the cathode gas 3. The temperature of the fuel cell 20 was maintained.

However, in such a conventional cooling means, since the heat generation amount of the fuel cell is large, the amount of the cathode exhaust gas 7 mixed in the cathode gas 3 becomes very large (for example, 10 times or more of the cathode gas required for the reaction). ), The pipe diameter of the cathode gas circulation line 26 becomes large, and the high temperature blower 24
Has a problem that it becomes large and requires large power. On the other hand, the fuel gas 1 is preheated by the fuel preheater 11 and supplied to the reformer, but there is a problem that the fuel preheater 11 is also large.

The present invention was devised to solve the above-mentioned problems. That is, the object of the present invention is to
(EN) A fuel cell power generator capable of reducing the flow rate of cathode exhaust gas mixed in cathode gas, thereby reducing the diameter of the cathode gas circulation line, downsizing the high temperature blower, and reducing the power of the high temperature blower. .

[0006]

According to the present invention, a fuel cell for generating electric power from an anode gas containing hydrogen and a cathode gas containing oxygen, and an anode exhaust gas discharged from the fuel cell is burned with a part of the cathode exhaust gas. A fuel cell power generator comprising a reformer for reforming a fuel gas into an anode gas by the heat thereof, wherein the fuel cell has a built-in fuel preheater for indirectly heating the fuel gas. A generator is supplied.

[0007]

According to the structure of the present invention, since the fuel cell has the built-in fuel preheater for indirectly heating the fuel gas, the reaction gas of the fuel cell can indirectly heat the fuel gas. Therefore, it is not necessary to separately provide a fuel preheater, heat retention and piping are reduced, and the overall size can be reduced. Further, since a part of the calorific value of the fuel cell is removed by the fuel gas, the amount of cathode exhaust gas mixed in the cathode gas is reduced, which reduces the diameter of the cathode gas circulation line and downsizes the high temperature blower. And, the power of the high temperature blower can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same parts as those in FIG. 2 are designated by the same reference numerals and used. FIG. 1 is an overall configuration diagram of a fuel cell power generator according to the present invention. In this figure, a fuel cell power generator according to the present invention includes a reformer 10 for reforming a fuel gas 1 into an anode gas 2 containing hydrogen, and a fuel cell 20 for generating power from an anode gas 2 and a cathode gas 3 containing oxygen.
And an air preheater 32 for recovering heat from the combustion exhaust gas 5 exiting the reformer 10. The reformer 10 is a fuel cell 2
The anode gas (ie, the anode exhaust gas 4) having a value of 0 is burned by a part of the cathode gas (ie, the cathode exhaust gas 7), which has exited the fuel cell 20, and the heat thereof reforms the fuel gas 1 into the anode gas 2. ing. Further, the fuel cell power generation device uses the combustion exhaust gas 5 that has exited the reformer 10 as the fuel cell 2
Exhaust gas circulation line 3 for supplying cathode gas 3 entering 0
0, and a power recovery device 40 that compresses air with the remainder of the cathode exhaust gas 7 that has exited the fuel cell 20 and supplies it to the exhaust gas circulation line 30.

The fuel cell 20 is stored in a storage container 22. Further, the fuel cell 20 according to the present invention includes a fuel preheater 28 that indirectly heats the fuel gas 1. The fuel preheater 28 is preferably sandwiched between a plurality of cells (not shown) constituting the fuel cell 20 and has a fuel gas passage separate from the fuel cell 20. That is, although the fuel preheater 28 has independent flow paths, it is preferable that the fuel preheater 28 is substantially integrally formed, stored in the same storage container 22, and kept warm in common.

With this configuration, the fuel gas can be indirectly heated by the reaction heat of the fuel cell. For this reason,
It is not necessary to provide a separate fuel preheater, heat insulation and piping are reduced, and the overall size can be reduced.

[0011]

As described above, the fuel cell power generator of the present invention can indirectly heat the fuel gas by the reaction heat of the fuel cell. Therefore, it is not necessary to separately provide a fuel preheater, and the heat insulation is maintained. The amount of cathode exhaust gas to be mixed with the cathode gas is reduced, because part of the calorific value of the fuel cell is removed by fuel gas, As a result, the pipe diameter of the cathode gas circulation line can be reduced, the high temperature blower can be downsized, and the power of the high temperature blower can be reduced.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a fuel cell power generator according to the present invention.

FIG. 2 is an overall configuration diagram of a conventional fuel cell power generator.

[Explanation of symbols]

 1 Fuel Gas 2 Anode Gas 3 Cathode Gas 4 Anode Exhaust Gas 5 Combustion Exhaust Gas 6 Air 7 Cathode Exhaust Gas 8 Purge Gas 10 Reformer 11 Fuel Preheater 20 Fuel Cell 22 Containment Vessel 24 High Temperature Blower 26 Cathode Gas Circulation Line 28 Fuel Preheater 30 Exhaust Gas Circulation line 32 Air preheater 33 Condenser 34 Steam separator 40 Power recovery device Re Reforming chamber Co Combustion chamber A Anode side C Cathode side

Claims (1)

[Claims] 1. A fuel cell for generating power from an anode gas containing hydrogen and a cathode gas containing oxygen, and the anode exhaust gas that has exited the fuel cell is burned in a part of the cathode exhaust gas, and the heat converts the fuel gas into the anode gas. A fuel cell power generation device comprising: a reformer that improves the quality of the fuel cell, wherein the fuel cell includes a fuel preheater that indirectly heats a fuel gas.