JPH0945349A - Fuel cell power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generation device whose overall efficiency is high and which is safe when battery performance is improved by increasing a supply quantity of reformed gas, by further providing a specific apparatus in the power generation device having the prescribed constitution. SOLUTION: The power generation device is provided with a fuel reformer 4 to reform fuel into reformed gas having high hydrogen concentration and a fuel cell main body 1 to generate electric power by electrochemical reaction by introducing the reformed gas and air, and uses the reformed gas discharged from the fuel cell main body 1 as reforming energy of the fuel reformer 4. This power generation device is also provided with a catalytic burner 12 to introduce and burn a part of the reformed gas discharged from the fuel cell main body 1 and at least a part of air discharged from the fuel cell main body 1 and a heat exchanger 13 to receover heat generated by combustion. That is, the reformed gas is reacted with air by the catalytic burner 12 without making a temperature of the fuel reformer 4 excessively high, and heat is effectively used recovering generating heat by the heat exchanger 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high heat utilization configuration of a fuel cell power generator which receives a reaction gas and generates electricity by an electrochemical reaction.

[0002]

2. Description of the Related Art A fuel cell power generator is mainly composed of a fuel cell main body and a fuel reformer, and is a reformer obtained by reforming a fuel such as natural gas as a reaction gas in the fuel reformer. Gas and air are sent to the fuel cell body, and electric power is taken out from hydrogen in the reformed gas and oxygen in the air by an electrochemical reaction.

FIG. 3 is a basic configuration diagram of a reaction gas system of a conventional fuel cell power generator. In the figure, the fuel cell main body 1 is schematically shown. A unit cell in which an electrolyte layer (not shown) is sandwiched between a fuel electrode and an air electrode, and a cooling pipe 3 arranged every time a plurality of unit cells are stacked. Is composed of a cooling plate 2. The fuel is mixed with the steam supplied from the steam separator 7 at a constant ratio and sent to the fuel reformer 4, and a reformed gas having a high hydrogen concentration is generated through a catalyst layer of the fuel reformer 4. Fuel cell body 1
Is supplied to the fuel electrode. Air is supplied to one air electrode by the blower 6. The reformed gas discharged from the fuel electrode containing the residual hydrogen that has not contributed to the electrochemical reaction in the fuel cell body 1 is the reformer burner 5 of the fuel reformer 4.
Is used to heat and reform the fuel reformer 4 to support the reforming reaction. Cooling water sent from the steam separator 7 is passed through the cooling water circulation pump 8 through the cooling water heat recovery heat exchanger 9 to the cooling pipe 3 embedded in the cooling plate 2 of the fuel cell main body 1 to generate electricity. The heat generated by the chemical reaction is removed, and the temperature of the fuel cell body 1 is kept constant.
The heated cooling water is returned to the steam separator 7 and separated into water and steam, and a part of the steam is used for reforming the fuel as described above.

[0004]

The power generation characteristics of the fuel cell body 1 are improved as the supply amount of the reaction gas is increased. Further, as the supply amount of the reaction gas increases, the in-plane uniformity increases, so that the local burden is reduced. Further, in order to extend the life, it is considered effective to increase the supply amount of the reaction gas to avoid local concentration. Therefore, it is desirable to increase the supply amount of the fuel reforming gas and air in order to improve the cell characteristics. Of these, air has already been increased without any obstacle to the increase in supply. However, if the supply amount of the fuel reformed gas is increased, the amount of the exhausted reformed gas sent to the reformer burner 5 is increased, and the temperature of the fuel reformer 4 may rise above the temperature control limit. is there. Therefore, in order to avoid this, a method is adopted in which a part of the reformed gas discharged from the fuel electrode is discharged to the outside without being sent to the reformer burner 5. In this method, the reformed gas is discharged to the outside. However, there is a problem in that the overall efficiency of the fuel cell power generator is reduced because it is directly discharged to the outside, and there is a problem that the safety is deteriorated because the combustible reformed gas is directly discharged to the outside.

An object of the present invention is to solve the above problems and provide a fuel cell power generator having high overall efficiency, safety, and excellent cell characteristics.

[0006]

In order to achieve the above object, in the present invention, a fuel reformer for reforming a fuel into a reformed gas having a high hydrogen concentration, and a reformed gas and air are introduced. In a fuel cell power generation device that uses a reformed gas discharged from the fuel cell body as reforming energy of a fuel reformer,
A catalytic combustor for introducing and burning a part of the reformed gas discharged from the fuel cell body and at least a part of the air discharged from the fuel cell body, and a heat exchanger for recovering heat generated by the combustion I will.

According to this structure, when the amount of reformed gas sent to the fuel cell main body is increased to improve the power generation characteristics, the reformer burner out of the reformed gas discharged from the fuel cell main body is used. If the excess of capacity is sent to the heat exchanger through the catalytic combustor, the temperature of the fuel reformer will not become excessive and the catalytic combustor will react with air to burn and generate heat. The heat is effectively used by recovering it with the heat exchanger. Further, in this configuration, the reformed gas is discharged after being burned, which is safe.

[0008]

FIG. 1 is a basic configuration diagram of a reaction gas system of a fuel cell power generator showing an embodiment of the present invention. In this figure, components having the same functions as those of the conventional embodiment shown in FIG. 3 is different from FIG. 3 in that a part of the exhaust reformed gas discharged from the fuel electrode and the air electrode of the fuel cell main body 1 and a part of the exhaust air pass through the control valve 11 and the manual valve 14, respectively. Is sent to the catalytic combustor 12, is further sent to the heat exchanger 13, and is then discharged. Therefore, in this configuration, even when the supply amount of the reformed gas is increased in order to improve the battery characteristics, all the exhausted reformed gas that is excessive with respect to the reformer burner is sent to the catalytic combustor 12. The heat generated by the heat exchanger 13 is recovered by the heat exchanger 13, so that the overall efficiency of the fuel cell power generator is improved, and the combustible gas is not released, which is safe.

FIG. 2 is a basic configuration diagram of a reaction gas system of a fuel cell power generator showing another embodiment of the present invention.
2 is different from FIG. 1 in that all the exhaust air discharged from the air electrode of the fuel cell body 1 is sent to the catalytic combustor 12 and is discharged via the heat exchanger 13. It is in. Also in this configuration, as in the case of FIG. 1, all the excess reformed reformed gas is sent to the catalytic combustor 12 and burned, and the heat generated by the heat exchanger 13 is recovered.

[0010]

As described above, according to the present invention, a fuel reformer for reforming a fuel into a reformed gas having a high hydrogen concentration, and a fuel cell for introducing a reformed gas and air to generate electricity by an electrochemical reaction. In a fuel cell power generator including a main body and using reformed gas discharged from the fuel cell main body as reforming energy of a fuel reformer, a part of the reformed gas discharged from the fuel cell main body and the fuel cell main body Since it is equipped with a catalytic combustor that introduces and combusts at least a portion of the air that is exhausted from it, and a heat exchanger that recovers the heat generated by combustion, the supply of reformed gas to improve the battery characteristics Even when the amount is increased, the heat can be effectively utilized, and it is possible to obtain a fuel cell power generator having high overall efficiency, safety, and excellent cell characteristics.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of a reaction gas system of a fuel cell power generator showing an embodiment of the present invention.

FIG. 2 is a basic configuration diagram of a reaction gas system of a fuel cell power generator showing another embodiment of the present invention.

FIG. 3 is a basic configuration diagram of a reaction gas system of a conventional fuel cell power generator.

[Explanation of symbols]

 1 Fuel Cell Main Body 2 Cooling Plate 4 Fuel Reformer 5 Reformer Burner 6 Blower 7 Steam Separator 10 Blower 11 Control Valve 12 Catalytic Combustor 13 Heat Exchanger 14 Manual Valve

Claims (1)

[Claims] 1. A fuel reformer for reforming a fuel into a reformed gas having a high hydrogen concentration, and a fuel cell main body for introducing reformed gas and air to generate electricity by an electrochemical reaction. In a fuel cell power generator that uses the discharged reformed gas as reforming energy for a fuel reformer, at least part of the reformed gas discharged from the fuel cell body and at least part of the air discharged from the fuel cell body A fuel cell power generation device comprising: a catalytic combustor that introduces and combusts a gas, and a heat exchanger that recovers heat generated by the combustion.