JPH09129254A - Fuel cell power generation facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generation facility having the capability of housing a reformer and a fuel cell in a pressure vessel of relatively simple structure, and substantially reducing heat release loss from a high temperature pipeline. SOLUTION: Regarding the fuel cell power generation facility where cathode exhaust gases 7 from a fuel cell 11 are fed to the combustion chamber of a reformer 10, an exhaust gas introduction line 24 is provided for introducing a part 5a of combustion exhaust gases 5 from the reformer 10 to the turbine of a turbine compressor 12, together with a circulation line 26 for feeding a mixture of the remnant 5b of the combustion exhaust gases and the pressurized air 6 resulting from the operation of the turbine compressor 12 to the cathode of the fuel cell 11. Furthermore, the facility is equipped with a pressure vessel 28 for housing the reformer 10 and the fuel cell 11.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a fuel cell power generation facility using a molten carbonate fuel cell.

[0002]

2. Description of the Related Art Molten carbonate fuel cells have features that are not found in conventional power generation equipment, such as high efficiency and little impact on the environment, and are attracting attention as power generation systems following hydro, thermal and nuclear power. It is currently being researched and developed around the world. Particularly 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 11 for generating power from an anode gas 2 and a cathode gas 3 containing oxygen is provided, and the anode gas 2 produced by the reformer 10 is supplied to the fuel cell 11 and most of it (in the fuel cell) After consuming 80%), it is supplied to the combustion chamber Co of the reformer as the anode exhaust gas 4. In the reformer 10, combustible components (hydrogen, carbon monoxide, methane, etc.) in the anode exhaust gas are burned by the cathode exhaust gas, and the high temperature combustion gas heats the reforming chamber Re to reform the fuel in the reforming chamber. The combustion exhaust gas 5 exiting the reforming chamber is cooled by the pressurized air 6 in the air preheater 13b, then pressurized by the low temperature blower 17c, and joined with the pressurized air 6 preheated in the air preheater 13b to form a cathode. Gas 3 is supplied. The low temperature blower 17c is also called a CO ₂ recycle blower because it supplies the CO ₂ gas generated in the reformer to the cathode side of the fuel cell and utilizes it for the cathode reaction.

The cathode gas (cathode exhaust gas 7) partially reacted in the fuel cell is partially circulated upstream of the fuel cell by a high-temperature blower 17b, and the remaining part 7a is sent to a reformer for combustion. The remaining 7b is supplied as air, the pressure of the remaining 7b is recovered by the turbine compressor 12, and is discharged out of the system after heat recovery by the exhaust heat recovery device 19. In FIG. 2,
13a is a fuel preheater, 14 is a desulfurizer, 15 is a check valve,
6 is a heater, 17d is an air blower, and 18 is a hot air generator.

However, in the conventional fuel cell power generation facility shown in FIG. 2, a CO ₂ recycling blower (low temperature blower 17
An air preheater 13b is installed at the inlet of c) to lower the blower inlet temperature and to keep the battery inlet temperature at an appropriate temperature (about 580 ° C).
Since the temperature of the air preheater 13b is large, the inlet temperature difference of the air preheater 13b is large (for example, 750 ° C. or higher),
There is a problem that the operating condition of 3b) is severe and the device becomes large.

Therefore, the inventor of the present application created a fuel cell power generation facility shown in FIG. 3 and filed a prior application (Japanese Patent Application No. 7-250).
No. 724, unpublished). This fuel cell power generation facility is configured to supply the combustion exhaust gas 5 of the reformer 10 to the cathode side 3 of the fuel cell 11, and to supply the low temperature pressurized air 6 and the high temperature combustion exhaust gas 5 supplied to the cathode side. A gas mixer 20 for directly mixing the mixed gas, a low temperature blower 21 for pressurizing the mixed gas whose temperature has been lowered, and a circulation line 22 for supplying the pressurized mixed gas to the cathode side of the fuel cell.
The circulation line 22 is provided with a check valve 23 that prevents the reverse flow of the cathode gas 3.

With the above-described structure, the low temperature (eg, about 20 ° C.) compressed air 6 supplied to the cathode side 3 by the gas mixer 20 and the high temperature (eg, about 770 ° C.) combustion exhaust gas 5 are directly mixed. By this mixing, the temperature of the mixed gas can be made low (for example, about 600 ° C.). Further, since the gas mixer 20 directly mixes the two fluids, it is possible to manufacture one having a large allowable temperature difference with a simple structure, at a small size, and at a low cost. Therefore, without using a large heat exchanger such as a shell-and-tube heat exchanger, a CO ₂ recycling blower (low temperature blower 2
It became possible to lower the inlet temperature of 1).

[0007]

In a fuel cell power generation facility, downsizing of the device, increase in power generation efficiency, and cost reduction are major problems. In the fuel cell power generation equipment shown in FIGS. 2 and 3, the reformer 10 and the fuel cell 11 are installed separately, so the equipment becomes large and the heat generation from the high temperature pipe connecting them reduces the power generation efficiency. There was a problem to do. Therefore, a portion surrounded by a broken line in FIGS. 2 and 3 is installed in the same pressure vessel, and preferably the reformer 10 and the fuel cell 11 are integrated to downsize the device, increase power generation efficiency, and reduce cost. It was hoped that

However, as is apparent from FIGS. 2 and 3, even if the reformer 10 and the fuel cell 11 are installed in the same pressure vessel, the cathode exhaust gas 7 of the fuel cell 11 will be discharged from the reformer 10. Line 7a led to the combustion chamber, turbine compressor 1
Line 7b led to the turbine of No. 2 and fuel cell 11
Of the line 7c that is recirculated to the cathode gas 3 of the above, and two of these lines 7b and 7c need to penetrate the pressure vessel and be taken out to the outside, so that the pressure vessel is complicated. There is a problem that the heat radiation loss from the two high temperature lines 7b and 7c reaching about 750 ° C. cannot be reduced.

The present invention has been made in order to solve such a problem. That is, an object of the present invention is to provide a fuel cell power generation facility capable of accommodating a reformer and a fuel cell with a pressure vessel having a relatively simple structure and capable of significantly reducing heat radiation loss from high temperature piping. To provide.

[0010]

According to the present invention, in the fuel cell power generation equipment for supplying the cathode exhaust gas of the fuel cell to the combustion chamber of the reformer, a part of the combustion exhaust gas of the reformer is supplied to the turbine compressor. An exhaust gas introduction line to be introduced into the turbine,
There is provided a fuel cell power generation facility, comprising: a circulation line for supplying a mixed gas of the remainder of combustion exhaust gas and air compressed by a turbine compressor to a cathode side of a fuel cell. According to a preferred embodiment of the present invention, a pressure vessel accommodating the reformer and the fuel cell is provided.

According to this structure of the present invention, the cathode exhaust gas of the fuel cell is entirely introduced into the combustion chamber of the reformer,
A part of the combustion exhaust gas from the reformer is introduced from the exhaust gas introduction line to the turbine of the turbine compressor, and the remainder of the combustion exhaust gas and the compressed air from the turbine compressor are introduced to the cathode gas of the fuel cell instead of the cathode exhaust gas. A mixed gas is supplied. Since the cathode exhaust gas and the combustion exhaust gas have substantially the same temperature and pressure, this configuration can maintain the performance of the turbine compressor. Further, although the temperature and pressure of the mixed gas for the cathode exhaust gas and the fuel cell are slightly different, the temperature can be freely adjusted by the heater 16 and the pressure can be freely adjusted by the low temperature blower 21. Therefore, with the above configuration, while maintaining the performance of the turbine compressor and the fuel cell, the above-mentioned two high temperature lines 7b of the cathode exhaust gas,
7c can be eliminated, and when a pressure vessel for accommodating the reformer and the fuel cell is provided, the reformer and the fuel cell can be accommodated by the pressure vessel of a relatively simple structure, and The heat radiation loss can be reduced significantly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common parts are denoted by the same reference numerals. FIG. 1 is an overall configuration diagram of a fuel cell power generation facility according to the present invention. In this figure, the fuel cell power generation facility of the present invention is equipped with an exhaust gas introduction line 24 for introducing a part 5a of the combustion exhaust gas 5 of the reformer 10 into the turbine of the turbine compressor 12, a residual portion 5b of the combustion exhaust gas 5, and a turbine compression. A circulation line 26 for supplying a mixed gas of the machine 12 with the pressurized air 6 to the cathode side of the fuel cell 11.

A check valve 24a is provided in the exhaust gas introduction line 24.
Is installed to prevent backflow of exhaust gas. In addition, the high temperature gas supplied from the hot air generating furnace 18 joins the exhaust gas introduction line 24 after passing through the heater 16. Since the cathode exhaust gas 7 and the combustion exhaust gas 5 have almost the same temperature and pressure, the performance of the turbine compressor 12 can be maintained by this configuration.

The mixer 20 and the low temperature blower 21 shown in FIG. 3 are installed in the circulation line 26, and the cathode circulation line 7c from the fuel cell 11 and the high temperature blower 17b are eliminated. Further, the flow rate of the low temperature blower 21 is set to a large flow rate obtained by adding the flow rate of the cathode circulating gas 7c to the flow rate of the conventional low temperature blower. With this configuration, the cathode exhaust gas 7
Although the temperature and pressure of the mixed gas are slightly different from each other, the temperature can be freely adjusted by the heater 16 and the pressure can be freely adjusted by the low temperature blower 21.

Further, the fuel cell power generation facility of the present invention further comprises
A pressure vessel 28 for accommodating the reformer 10 and the fuel cell 11 is provided. As is clear from FIG. 1, when the reformer 10 and the fuel cell 11 are installed in the same pressure vessel 28, the cathode exhaust gas 7 of the fuel cell 11 is introduced into the combustion chamber of the reformer 10 (conventional line). Only the line 7a) and the conventional lines 7b and 7c are abolished. Therefore, the total number of parts that penetrate the pressure vessel to the outside is 5 to 3 parts (indicated by small circles), and the heat radiation loss from the two conventional high temperature lines 7b and 7c that reach approximately 750 ° C is substantially eliminated. You can get rid of it.

That is, according to the present invention described above, the two high temperature lines 7b, 7c of the cathode exhaust gas can be eliminated while maintaining the performance of the turbine compressor and the fuel cell, and the reformer and the fuel can be eliminated. When the pressure vessel for accommodating the battery is provided, the reformer and the fuel cell can be accommodated by the pressure vessel having a relatively simple structure, and the heat radiation loss from the high temperature pipe can be significantly reduced.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0018]

As described above, in the fuel cell power generation equipment of the present invention, the reformer and the fuel cell can be housed by the pressure vessel having a relatively simple structure, and the heat radiation loss from the high temperature piping is greatly reduced. It has an excellent effect that it can be reduced to

[Brief description of the drawings]

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

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

FIG. 3 is an overall configuration diagram of a fuel cell power generation facility according to a prior application by the inventor of the present application.

[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 Steam 10 Reformer 11 Fuel cell 12 Turbine compressor 13a Fuel preheater 13b Air preheater 14 Desulfurizer 15 Check valve 16 Heating 17a Fuel blower 17b High temperature blower 17c Low temperature blower 17d Air blower 18 Hot air generator 19 Exhaust heat recovery device 20 Gas mixer 21 Low temperature blower 22 Circulation line 23 Check valve 24 Exhaust gas introduction line 24a Check valve 26 Circulation line 28 Pressure vessel

Claims (2)

[Claims] 1. In a fuel cell power generation facility for supplying cathode exhaust gas of a fuel cell to a combustion chamber of a reformer, an exhaust gas introduction line for introducing a part of combustion exhaust gas of the reformer into a turbine of a turbine compressor, and a combustion system. A fuel cell power generation facility, comprising: a circulation line for supplying a mixed gas of the remainder of exhaust gas and air compressed by a turbine compressor to a cathode side of a fuel cell. 2. The fuel cell power generation facility according to claim 1, further comprising a pressure vessel accommodating the reformer and the fuel cell.