JPH0547395A - Fuel cell power generating device - Google Patents

Abstract

PURPOSE:To reduce the generated thermal stress by connecting reformers and fuel cells in series in turn in the flow direction of the fuel gas and reforming the minimum required fuel gas for the cells with the airs heated by the waste gas for the required heat quantity. CONSTITUTION:Heated airs 11a, 1b recovered by an air heater 6 installed on the downstream side are utilized as heat sources of reformers 3, 4. The reformers 3, 4 and fuel cells 1, 2 are combined in series in turn in the flow direction X of the fuel gas 7 in multiple stages, the constituent of reform gases 9, 15 is adjusted by the heat quantity fed to the reformers 3, 4 on the upstream side and the adjustment of vapors 8a, 8b, and the temperature distribution of the fuel cells 1, 2 just behind the reformers 3, 4 is adjusted. The heat and vapor generated by the fuel cell on the upstream side can be utilized for the second stage and subsequent reformers. When the heat absorption quantity and heat generation quantity are balanced, a fuel cell power generating device having reformers 3, 4 with little generated thermal stress can be obtained.

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 using natural gas.

[0002]

2. Description of the Related Art As is well known, a flat plate type solid electrolyte fuel cell using a fuel gas such as natural gas or coal gas is known. Such a fuel cell generally has a structure including an air electrode, an electrolyte, and a fuel electrode. However, the inventors of the present invention have not yet found out about the published examples of the fuel cell power generation device using such a flat plate type solid electrolyte fuel.

[0003]

However, in the conventional flat plate solid electrolyte fuel cell, (a) the amount of heat absorption on the fuel electrode side required for reforming the fuel gas (natural gas, coal gas) and (b) ) Because of the amount of heat generated that is proportional to the amount of power generated on the air electrode side due to power generation, a large temperature difference occurs within the fuel cell, and the fuel cell is damaged by thermal stress. Therefore, at present, there is no example of a fuel cell power generator using such a fuel cell.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a fuel cell power generator having a reformer by reducing the generated thermal stress by balancing the heat absorption amount and the heat generation amount. And

[0005]

The present invention has a plurality of flat plate type solid electrolyte fuel cells and a reformer arranged upstream of the fuel cell, respectively, and the reformer and the fuel cell are provided. And a plurality of fuel cells are alternately connected in series in the flow direction of the fuel gas, and the amount of heat required for the reformer is supplied from the air heated by the exhaust gas. It is a fuel cell power generation device characterized by sequentially reforming a required minimum required fuel gas.

[0006]

By separating the fuel cell and the reformer, it becomes possible to select a catalyst having an optimum composition and shape for the reformer. In addition, by combining a plurality of reformers and fuel cells and arranging them in series, each reformer can control the temperature distribution of the fuel cell immediately after it and reduce the amount of heat required for reforming. A part of the fuel gas can be used in the form of temperature rise by the fuel cell (the amount of power generated by the immediately preceding fuel cell). Further, it becomes possible to downsize the air heater installed in the exhaust gas.

[0007]

EXAMPLE A multistage internal reforming fuel cell power generator according to an example of the present invention will be described below with reference to FIG.

Reference numerals 1 and 2 in the figure respectively denote a first-stage and a second-stage flat-plate solid electrolyte fuel cell (flat-plate SOFC). First-stage and second-stage reformers 3 and 4 are disposed upstream of the SOFCs 1 and 2, respectively. Where the SOFC
1, 2 and reformers 3, 4 are alternately connected in series in the flow direction X of the fuel gas. An after-burner 5 and an air heater 6 are arranged on the downstream side of the SOFC 2.

The reformer 3 contains natural gas (coal gas).
7 and steam 8a are introduced respectively. Here, by the action of the catalyst 21, it becomes a partial reformed gas (mixed gas of hydrogen and carbon monoxide and unreformed natural gas) 9, and the fuel cell 1 on the downstream side.
Is supplied to. Further, the heat required for reforming is supplied to the reformers 3 and 4 from the air 10 supplied to the air heater 6 as heated air 11a and 11b.

In the SOFC 1, electric power is generated by the partial reformed gas 9 and the battery air 12a, and the battery residual fuel gas 13 and the battery residual air 14 are discharged as respective residual gases.
Hydrogen and carbon monoxide are consumed from the partial reformed gas 9 in the residual fuel gas 13 of the cell, and it becomes a mixed gas of most natural gas 7 and a small amount of steam and carbon dioxide gas. These flow in along with the steam 8b to be added again to the reformer 4 on the downstream side, and become the reformed gas 15 by the action of the reformer 4 in the second stage, and flow into the SOFC 2 in the second stage. In the figure, 16 indicates a heating pipe and 17 indicates exhaust gas.

In this embodiment, since the SOFC 2 is the final stage, the reformed gas 15 is completely reformed into hydrogen and carbon monoxide without leaving the natural gas 7, and the SOFC 2 effectively converts it into electric power.

Therefore, according to the above-described embodiment, (1) The heated air 11a, 11b collected by the air heater 6 installed on the downstream side can be used as the heat source of the reformers 3, 4.

(2) The reformers 3 and 4 and the SOFCs 1 and 2 are alternately combined in series in the flow direction of the fuel gas in series to adjust the amount of heat supplied to the reformers 3 and 4 on the upstream side and steam. By adjusting the components of the reformed gas, the temperature distribution of the SOFCs 1 and 2 immediately after can be adjusted.

(3) In the reformers 3 and 4 of the second and subsequent stages, it is possible to utilize the heat generated by the power generation generated in the upstream SOFC and the use of steam. Therefore, it is possible to realize a power generator using a multi-stage reforming flat plate type solid electrolyte fuel cell.

In the above embodiment, the SOFC and the reformer are arranged in two stages, but the present invention is not limited to this, and it is a matter of course that three or more stages may be arranged.

[0016]

As described above in detail, according to the present invention, it is possible to provide a fuel cell power generator having a reformer by reducing the generated thermal stress by balancing the heat absorption amount and the heat generation amount.

[Brief description of drawings]

FIG. 1 is a multistage internal reforming fuel cell power generator according to an embodiment of the present invention.

[Explanation of symbols]

1, 2 ... Flat plate solid electrolyte fuel cell, 3, 4 ... Reformer,
5 ... Afterburner, 6 ... Air heater, 7 ... Natural gas,
8a, 8b ... Steam, 9 ... Partially reformed gas, 10 ... Air, 11
a, 11b ... Heating air, 12a, 12b ... Battery air, 13 ... Battery residual fuel gas, 16 ... Heating pipe, 17 ... Exhaust gas.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimi Ezaki, No. 20 Kitakanyama, Otaka-cho, Midori-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc. (72) Inventor Masatoshi Hattori Otaka, Midori-ku, Nagoya-shi, Aichi 1 of 20 Kitakanzan, Chubu Electric Power Co., Inc. (72) Inventor Mitsuhiro Irino 1-1-1, Niihama, Niihama, Arai-cho, Takasago, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Takasago Research Laboratory (72) Inventor Kazuhisa Tanaka Takasago, Hyogo Prefecture 2-1-1 Niihama, Arai-cho, Aichi-machi, Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Kazunobu Hashida 2-1-1, Niihama, Niihama, Arai-cho, Takasago-shi, Hyogo (72) Inventor Fusako Nanjo 1-1 1-1 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries Ltd. Kobe Shipyard (72) Inventor Masayuki Funazu Kobe, Hyogo Prefecture Hyogo-ku Wadasaki-cho, 1 Chome, Mitsubishi Heavy Industries, Ltd. in the Kobe Shipyard & Machinery Works (72) inventor Takenobu Koichi Kobe, Hyogo Prefecture, Hyogo-ku, Wadasaki-cho, chome No. 1 in the No. 1 Mitsubishi Heavy Industries, Ltd. Kobe Shipyard & Machinery Works

Claims (1)

[Claims] 1. A plurality of flat plate type solid electrolyte fuel cells,
A reformer disposed on the upstream side of each of the fuel cells, and a plurality of the reformers and the fuel cells are alternately connected in series in the flow direction of the fuel gas, and required for the reformer. The fuel cell power generator is characterized in that the required amount of fuel gas is supplied from the air heated by the exhaust gas, and the required minimum amount of fuel gas required for the fuel cell immediately after is further sequentially reformed by each reformer.