JPH0757752A - Fuel cell power generator - Google Patents

Abstract

PURPOSE:To provide a fuel cell power generator provided with a cell stack cooling system which does not need an ion exchange resin to be used to lower the conductivity of cooling water circulated in the cooling plate of the cell stack. CONSTITUTION:A heat exchanger 17 is inserted in the middle of the cooling system piping between a cell stack 1 and a steam separator 2, to separate the cooling channels between the channel of a heating medium for cooling circulating the heat exchanger and, the cell stack 1, and the heat exchanger 17 and the steam separator 2, are separated from one another, and an ion exchange resin 16 is removed. A fuel cell power generator of good maintenance can thus be provided.

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 cooling system for a cell stack (fuel cell stack).

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a configuration example of a conventional fuel cell power generation device, and FIG. 3 is a block diagram showing a configuration of a cell stack in the fuel cell power generation device of FIG.

As shown in FIG. 3, the cell stack 1 has a structure in which a plurality of unit cells 10 and cooling plates 11 are laminated. These unit cells 10 are unit fuel cells including a fuel electrode, an air electrode, and an electrolyte, are electrically connected in series via a cooling plate 11, and a circuit of a current flowing by an electromotive force generated in each unit cell 10 is The contact resistance is reduced by using each cooling plate 11 as a conductor. In addition, cooling pipes 14 are provided on each cooling plate 11 via insulators 12 and 13,
Since the cooling water flows inside the cooling plates 11 connected to each other, the conductivity of the cooling water needs to be sufficiently small in order to suppress the leakage current generated between the cooling plates 11.

In FIG. 2, the cooling plate of the cell stack 1 is connected to the steam separator 2 via the pumps 4 by the cooling pipes 14 and 15, and the cooling water is the ion exchange resin 16
Is connected to the steam separator 2 by a makeup water pipe 8. The steam separator 2 is connected to a heat recovery section 3 such as an absorption chiller, and mixes steam supplied from the steam separator 2 with fuel such as city gas supplied from the fuel supply pipe 7. It is connected to the ejector 5 which sends it to the reformer 6. Ejector 5
The steam-fuel mixture component mixed in (1) is reformed into hydrogen in the reformer 6 and supplied to the fuel electrode inlet of the cell stack 1. Further, the steam separator 2 is provided with a blow-down pipe 9 for preventing impurities such as silica mixed in water from being concentrated and settling in the steam separator 2 and the pipe.

As described above, it is necessary to lower the conductivity of the cooling water so as not to lower the insulation resistance between the cooling plates 11 of the cell stack 1, but in the system of FIG. The conductivity of water was lowered by supplying the water supplied to the vessel 2 through the ion exchange resin 16.
The capacity of the ion exchange resin 16 decreases as the operating temperature increases,
The maximum operating temperature is about 40 ° C. On the other hand, the operating temperature of the cell stack 1 that undergoes an exothermic reaction is about 190 ° C. in the case of a phosphoric acid aqueous solution type fuel cell, and cooling water is supplied to the cell stack 1 and steam for steam reforming the fuel is supplied to the ejector 5. Since the temperature of the steam / water separator 2 is about 160 ° C., the temperature inside the steam / water separator decreases when water of about 40 ° C. or less is being replenished to the steam / water separator, and the heat in the heat recovery unit is reduced. There was a problem that the amount of collection decreased.

[0006]

The above-mentioned conventional fuel cell power generator uses an ion exchange resin to reduce the conductivity of the cooling water circulating in the cooling plate of the cell stack. However, the effect of the ion exchange resin In order to maintain the above temperature, it is necessary to regenerate it frequently, and since it is necessary to use the water at a temperature of about 40 ° C. or less, there is a problem that the efficiency of the heat recovery part is lowered when water is replenished.

An object of the present invention is to realize a fuel cell power generator having a cell stack cooling system which does not require an ion exchange resin, which has many restrictions in use as described above.

[0008]

In the fuel cell power generator of the present invention, the cooling system piping between the cell stack and the steam separator is connected via a heat exchanger.

[0009]

By providing a heat exchanger in the middle of the cooling pipe for collecting the exhaust heat from the cell stack to the steam separator, the cooling plate of the cell stack is provided with cooling water supplied from the steam separator side. Would circulate a separate cooling medium.

[0010]

EXAMPLE An example will be described with reference to FIG.

FIG. 1 is a block diagram of an embodiment of the fuel cell power generator of the present invention.

In this fuel cell power generator, a heat exchanger 17 is inserted in the middle of the cooling system pipe between the cell stack 1 and the steam separator 2 of the conventional example. The flow path of the cooling medium circulated in the cooling plate of the cell stack 1 is connected from the heat exchanger 17 to the cooling pipe 15 via the pump 18, and passes through each cooling plate to pass from the cooling pipe 14 to the heat exchanger 17. And forms a flow path separate from the flow path of the cooling medium between the steam separator 2 and the heat exchanger 17. The water supplied to the steam separator is supplied from the makeup water pipe without passing through the ion exchange resin. In this case, it suffices to use a cooling medium having a low conductivity as the cooling medium that flows back through the flow path that enters the cooling plate.

[0013]

As described above, according to the present invention, by separating the flow path of the cooling medium circulated in the cooling plate of the cell stack and the flow path of the cooling medium coming in and out of the steam separator, Effect of eliminating the need to use an ion-exchange resin and eliminating the need to limit the temperature of water to be replenished to the steam separator to about 40 ° C or less, and realizing a fuel cell power generator with extremely high maintainability and economy There is.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a fuel cell power generator of the present invention.

FIG. 2 is a block diagram showing a configuration example of a conventional fuel cell power generation device.

FIG. 3 is a block diagram showing a configuration of a cell stack.

[Explanation of symbols]

 1 Cell Stack 2 Steam / Water Separator 3 Heat Recovery Part 4, 18 Pump 5 Ejector 6 Reformer 7 Fuel Supply Pipe 8 Makeup Water Pipe 9 Blow Down Pipe 10 Unit Cell 11 Cooling Plate 12, 13 Insulators 14, 15 Cooling Pipe 16 Ion exchange resin 17 Heat exchanger

Front page continuation (72) Inventor Shigumi Iida 1-6, Uchisaiwai-cho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Shuichi Kitada 1-1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Nihon Telegraph Phone Co., Ltd.

Claims (2)

[Claims] 1. A fuel cell power generator having a cell stack and a steam separator, wherein a cooling system pipe between the cell stack and the steam separator is connected via a heat exchanger. Battery generator. 2. The fuel cell power generator according to claim 1, wherein a pump is provided in the cooling system piping on the side of the cell stack that is separated via the heat exchanger.