JP3601734B2 - Fuel cell power generation equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell power generation facility using a molten carbonate fuel cell.
[0002]
[Prior art]
Molten carbonate fuel cells have features that are not found in conventional power generators, such as high efficiency and low environmental impact, and have attracted attention as a power generation system following hydro, thermal, and nuclear power. R & D is under way. In particular, in a power generation facility using a molten carbonate fuel cell using natural gas as a fuel, as shown in FIG. 2, a reformer 10 for reforming a fuel gas 1 such as natural gas into an anode gas 2 containing hydrogen, The fuel cell 11 includes an anode gas 2 and a fuel cell 11 that generates power from a cathode gas 3 containing oxygen. The anode gas 2 produced by the reformer 10 is supplied to the fuel cell 11 and most of the anode gas 2 is generated in the fuel cell ( After being consumed (for example, 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 reforming chamber Re is heated by the high-temperature combustion gas to reform the fuel in the reforming chamber. The combustion exhaust gas 5 that has exited the reforming chamber is cooled by pressurized air 6 in an air preheater 13b, then pressurized by a low-temperature blower 17c, merges with the pressurized air 6 preheated in the air preheater 13b, and becomes a cathode. It is supplied to gas 3. The low-temperature blower 17c is also called a CO ₂ recycle blower because it supplies CO ₂ gas generated in the reformer to the cathode side of the fuel cell and uses it for a cathode reaction.
[0003]
A part of the cathode gas (cathode exhaust gas 7) which has partially reacted in the fuel cell is circulated upstream of the fuel cell by the high-temperature blower 17b, and the remaining part 7a is supplied to the reformer as combustion air. The remaining 7b is recovered in pressure 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, 16 is a heater, 17d is an air blower, and 18 is a hot air generator.
[0004]
However, in the conventional fuel cell power generation equipment shown in FIG. 2, an air preheater 13b is installed at the inlet of a CO ₂ recycle blower (low-temperature blower 17c) to lower the blower inlet temperature and reduce the battery inlet temperature to an appropriate temperature (about (580 ° C.), the temperature difference at the inlet of the air preheater 13b is large (for example, 750 ° C. or more), the operating conditions of the heat exchanger (air preheater 13b) are severe, and there is a problem that the apparatus becomes large. Was.
[0005]
Therefore, the inventor of the present application has devised a fuel cell power generation facility shown in FIG. 3 and has filed an earlier application (Japanese Patent Application No. 7-250724, not disclosed). This fuel cell power generation equipment supplies the combustion exhaust gas 5 of the reformer 10 to the cathode side 3 of the fuel cell 11, and the low temperature pressurized air 6 and the high temperature combustion exhaust gas 5 supplied to the cathode side , A low-temperature blower 21 for pressurizing the mixed and cooled gas mixture, 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 for preventing the backflow of the cathode gas 3.
[0006]
According to the above-described configuration, the low-temperature (for example, about 20 ° C.) pressurized air 6 supplied to the cathode side 3 by the gas mixer 20 and the high-temperature (for example, about 770 ° C.) combustion exhaust gas 5 are directly mixed. The temperature of the mixed gas can be lowered (for example, about 600 ° C.). Further, since the gas mixer 20 directly mixes two fluids, a gas mixer having a large allowable temperature difference can be manufactured with a simple structure, in a small size and at low cost. Therefore, the inlet temperature of the CO ₂ recycle blower (low-temperature blower 21) can be reduced without using a large-sized heat exchanger such as a shell-and-tube heat exchanger.
[0007]
[Problems to be solved by the invention]
In fuel cell power generation equipment, downsizing of the device, increase in power generation efficiency, and cost reduction are major issues. In the fuel cell power generation equipment shown in FIGS. 2 and 3, since the reformer 10 and the fuel cell 11 are separately installed, the equipment becomes large, and the power generation efficiency is reduced due to heat radiation from a high-temperature pipe connecting the equipment. There was a problem to do. Therefore, the 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 reduce the size of the device, increase the power generation efficiency, and reduce the cost. It was desired to aim at.
[0008]
However, as is clear 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 flows into the combustion chamber of the reformer 10. It branches into three lines: a line 7a to be guided, a line 7b to be guided to the turbine of the turbine compressor 12, and a line 7c to be recirculated to the cathode gas 3 of the fuel cell 11, and two of these three lines 7b, 7c has a problem that not only does the pressure vessel become complicated, but also the heat loss from the two high-temperature lines 7b and 7c reaching about 750 ° C. cannot be reduced because it is necessary to penetrate the pressure vessel and take it out to the outside. was there.
[0009]
The present invention has been made to solve such a problem. That is, an object of the present invention is to provide a fuel cell power generation facility capable of housing a reformer and a fuel cell with a pressure vessel having a relatively simple structure and greatly reducing heat loss from high-temperature piping. To provide.
[0010]
[Means for Solving the Problems]
According to the present invention, there is provided a fuel cell power generation system for supplying a cathode exhaust gas of a fuel cell to a combustion chamber of a reformer, wherein the entire amount of the cathode exhaust gas of the fuel cell is supplied to a combustion chamber of the reformer. A pressure vessel accommodating the reformer and the fuel cell, an exhaust gas introduction line for introducing a part of the combustion exhaust gas of the reformer to the turbine of the turbine compressor, and the remaining air of the combustion exhaust gas and compressed air by the turbine compressor. And a circulation line for supplying a mixed gas of the fuel cell to the cathode side of the fuel cell, a pipe penetrating the pressure vessel, the circulation line, a combustion exhaust gas line for extracting combustion exhaust gas from a reformer, and a reforming line. A combustion cell power generation facility is provided in which only a fuel gas line for supplying a fuel gas to a reforming chamber of a vessel is provided .
[0011]
According to this configuration of the present invention, the entire amount of the cathode exhaust gas of the fuel cell is guided to the combustion chamber of the reformer, and a part of the combustion exhaust gas of the reformer is supplied from the exhaust gas introduction line to the turbine of the turbine compressor. Introduced, a mixed gas of the remaining part of the combustion exhaust gas and the compressed air by the turbine compressor is supplied to the cathode gas of the fuel cell instead of the cathode exhaust gas. 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. Although the temperature and pressure of the mixed gas to 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, the above-described two high-temperature lines 7b and 7c for the cathode exhaust gas can be eliminated while maintaining the performance of the turbine compressor and the fuel cell, and the pressure vessel for housing the reformer and the fuel cell can be provided. When it is provided, the reformer and the fuel cell can be housed in a pressure vessel having a relatively simple structure, and the heat loss from the high-temperature pipe can be significantly reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described 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 equipment of the present invention includes 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 remaining portion 5b of the combustion exhaust gas 5 and a turbine compression system. A circulation line 26 for supplying a gas mixture with the pressurized air 6 from the unit 12 to the cathode side of the fuel cell 11. The fuel cell power generation equipment is configured to supply the entire amount of the cathode exhaust gas of the fuel cell to the combustion chamber of the reformer.
[0013]
A check valve 24a is installed in the exhaust gas introduction line 24 to prevent the exhaust gas from flowing backward. 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 temperature and pressure of the cathode exhaust gas 7 and the combustion exhaust gas 5 are substantially the same, the performance of the turbine compressor 12 can be maintained by this configuration.
[0014]
The circulation line 26 is provided with the mixer 20 and the low-temperature blower 21 shown in FIG. 3, 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 temperature and pressure of the cathode exhaust gas 7 and the mixed gas are slightly different, but the temperature can be freely adjusted by the heater 16 and the pressure by the low-temperature blower 21.
[0015]
Further, the fuel cell power generation equipment of the present invention further includes a pressure vessel 28 that houses the reformer 10 and the fuel cell 11. As is apparent 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 supplied to a line (conventional art) led to the combustion chamber of the reformer 10. Only the line 7a), and the conventional lines 7b and 7c are eliminated. For this reason, the number of parts that penetrate the pressure vessel to the outside is 5 to 3 (indicated by small circles) in total, and the heat loss from the conventional two high-temperature lines 7b and 7c reaching about 750 ° C. is substantially reduced. Can be eliminated. In other words, the piping that penetrates the pressure vessel is only the circulation line 26, the flue gas line 31 that leads the flue gas from the reformer, and the fuel gas line 32 that supplies the fuel gas to the reforming chamber of the reformer. .
[0016]
That is, according to the present invention described above, the two high-temperature lines 7b and 7c for 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 cell can be housed. When a pressure vessel is provided, the reformer and the fuel cell can be housed in a pressure vessel having a relatively simple structure, and the heat loss from the high-temperature piping can be significantly reduced.
[0017]
It should be noted that the present invention is not limited to the above-described embodiment, and can be variously changed without departing from the gist of the present invention.
[0018]
【The invention's effect】
As described above, the fuel cell power generation equipment of the present invention can house the reformer and the fuel cell with a pressure vessel having a relatively simple structure, and can greatly reduce the heat loss from the high-temperature pipe. It has excellent effects such as being able 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 an earlier application by the present inventor.
[Explanation of symbols]
DESCRIPTION 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 Unit 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
31 flue gas line
32 Fuel gas line

Claims (1)

Fuel cell power generation equipment for supplying cathode exhaust gas of a fuel cell to a combustion chamber of a reformer,
A configuration in which the entire amount of the cathode exhaust gas of the fuel cell is supplied to the combustion chamber of the reformer,
A pressure vessel containing the reformer and the fuel cell, an exhaust gas introduction line for introducing a part of the combustion exhaust gas of the reformer to the turbine of the turbine compressor, and the remaining portion of the combustion exhaust gas and pressurized air by the turbine compressor. A circulation line for supplying the mixed gas of the above to the cathode side of the fuel cell,
The pipe penetrating the pressure vessel, the circulation line, a flue gas line for deriving flue gas from the reformer, and only a fuel gas line for supplying fuel gas to the reforming chamber of the reformer , Characteristic fuel cell power generation equipment.