JP2000156238A - Fuel cell power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell power generation device remarkably cutting the station motive power and the operation cost. SOLUTION: This fuel cell power generation device comprises an anode gas line 2, an anode exhaust gas reforming line 6, a carbonic acid gas recycling line 7 combusting the anode exhaust gas and the cathode exhaust gas by a catalyst combuster 23 to generate the combustion exhaust gas, heating a reformer 22, and supplying the gas to a cathode, a turbine compressor 2 for driving a compressor by rotating a turbin by the combustion gas obtained by combusting the anode exhaust gas and the cathode exhaust gas, to generate the compressed air to be supplied to the cathode, and an exhaust heat recovery vapour generator 30 generating the vapour by the turbin exhaust of a turbin compressor 28 to supply the same to the reformer 22. The anode exhaust gas reforming line 6 and the carbonic acid gas recycling line 7 are provided with the recycle blowers 32, 34, respectively for injecting the gas to seal the shaft, and the vapour generated from the exhaust heat recovery vapour generator 30 is used as the gas for sealing the shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a molten carbonate fuel cell power generator.

[0002]

2. Description of the Related Art Molten carbonate fuel cells have features not found in conventional power generators, such as high efficiency and low environmental impact, and have attracted attention as power generation systems following hydro, thermal and nuclear power. Currently, intensive research is underway.

FIG. 3 is a diagram showing an example of a power generation facility using a molten carbonate fuel cell using city gas as fuel. FIG.
In the power generation equipment, the reformer 22 reforms a fuel gas (city gas) mixed with steam into an anode gas containing hydrogen.
And a fuel cell 20 that generates power from a cathode gas containing oxygen and an anode gas containing hydrogen.
The anode gas generated in the fuel cell 20 is supplied to the fuel cell 20 through the anode gas line 2, and the anode gas is consumed in the fuel cell 20 to form an anode exhaust gas. Supplied to

[0004] In the catalytic combustor 23, combustible components (hydrogen, carbon monoxide, methane, etc.) in the anode exhaust gas are burned to generate a high-temperature combustion exhaust gas, which is supplied to a heating chamber of the reformer 22 and is subjected to the combustion exhaust gas. The reforming chamber is heated, and the fuel gas is reformed by the reforming catalyst in the reforming chamber to produce anode gas. The anode gas exchanges heat with the fuel gas mixed with the steam flowing through the fuel gas line 1 by the fuel preheater 24, and the fuel cell 20
Is supplied to the anode. Further, the flue gas discharged from the heating chamber is supplied to the cathode by a carbon dioxide gas recycling blower 32 in a carbon dioxide gas recycling line 7. The combustion exhaust gas contains a large amount of carbon dioxide, and serves as a supply source of carbon dioxide required for the battery reaction. Air from the air line 8 is supplied to the outlet side of the carbon dioxide gas recycle blower 32 to supply oxygen required for a cathode cell reaction. A part of the cathode exhaust gas discharged from the cathode is supplied to the cathode by the circulation line 3. The cathode exhaust gas, the combustion exhaust gas and the air are mixed to form a cathode gas, which is supplied to the cathode.
An anode exhaust gas reforming line 6 is provided on the anode outlet side, and converts the anode exhaust gas containing unburned fuel into an adiabatic reformer 36.
And supply it to the anode. The adiabatic reformer 36 fills a container with a reforming catalyst and insulates it to maintain a high temperature state of the anode exhaust gas and convert it into a reformed gas by a catalytic action.

The cathode gas undergoes a cell reaction in the fuel cell 20 to become a high-temperature cathode exhaust gas.
The other part is supplied to the catalytic combustor 23 by the cathode exhaust gas line 5, and the remaining part is combusted in the combustor 38 together with the anode exhaust gas, and the remaining part is supplied by the turbine compressor 28 that drives a compressor that compresses air. After the power is recovered, the heat energy is further recovered by the exhaust heat recovery steam generator 30 and discharged out of the system. The steam generated by the exhaust heat recovery steam generator 30 enters the fuel gas line 1 through the steam line 9, mixes with the fuel gas, and is sent to the reformer 22.

The carbon dioxide gas recycling line 7 is provided with a carbon dioxide gas recycling blower 32. Since the temperature of the gas to be handled is about 650 ° C., the compressed air is used for the shaft seal of the blower 32, and the compressed air is supplied from the in-house air compressor 40. The anode exhaust gas reforming line 6 is also provided with an anode recycle blower 34, and the temperature of the gas to be handled is about 650 ° C.
Gas is used for the shaft seal of the
2 supplies nitrogen.

[0007]

The amount of compressed air used in the carbon dioxide gas recycle blower 32 is a considerable amount, for example, 60 Nm ³ / h. It has become. Also,
The anode recycling blower 34 also uses a large amount of nitrogen gas, for example, as high as 30 Nm ³ / h, which causes an increase in operating costs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a fuel cell power generator that greatly reduces in-plant power and operating costs.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a fuel cell which generates electricity by using an anode gas containing hydrogen supplied to an anode and a cathode gas containing oxygen supplied to a cathode. An anode gas line that supplies fuel gas and steam to the anode as an anode gas in a reformer, an anode exhaust gas reforming line in which the anode exhaust gas is reformed in an adiabatic reformer and supplied to the anode, an anode exhaust gas and a cathode exhaust gas. The combustion gas is burned in a catalytic combustor to generate combustion exhaust gas, the reformer is heated and then supplied to the cathode after the carbon dioxide recycling line.The turbine is rotated by the combustion gas produced by burning the anode exhaust gas and the cathode exhaust gas to drive the compressor. A turbine compressor that generates compressed air and supplies it to the cathode, and steam is generated from the turbine exhaust of the turbine compressor to And a regenerative blower that injects gas and seals the shaft in the anode exhaust gas reforming line and the carbon dioxide gas recycling line. The steam generated by the exhaust heat recovery steam generator is used as the shaft sealing gas.

The steam generated by the exhaust heat recovery steam generator is:
It is sent to a fuel gas line, mixed with fuel gas, sent to a reformer, and used to generate anode gas. However, there is considerable room for capacity. Since both recycle blowers are used to transfer gas at least at 600 ° C. or higher, steam can be used as a shaft sealing gas. As a result, a reduction in power for in-house compressed air and a reduction in operating costs due to the elimination of expensive nitrogen gas are realized.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the fuel cell power generator of the present invention. The same reference numerals as those in FIG. 3 indicate the same lines, devices, and the like. Since the apparatus of FIG. 3 has been described in detail, differences from FIG. 3 will be described. In FIG. 1, an air compressor 40 for supplying compressed air to the carbon dioxide gas recycling blower 32 and a nitrogen gas supply device 4 for supplying nitrogen gas to the anode recycling blower 34 in FIG.
2 is removed, and the steam line 9 from the exhaust heat recovery steam generator 30 is connected to each of the blowers 32 and 34, and steam is supplied as a shaft seal gas. Thereby, the same sealing effect as when compressed air is supplied to the carbon dioxide gas recycle blower 32 and nitrogen gas is supplied to the anode recycle blower 34 can be obtained.

FIG. 2 is a view showing the structure of a shaft seal used in the carbon dioxide gas recycle blower 32 and the anode recycle blower 34. A heat-resistant material sleeve 51 made of graphite is fixed to the blower shaft 50, and a mating ring 52 made of SiC is fixed to the sleeve 51, and rotates together with the blower shaft 50. A sealing ring 53 made of carbon, which is in contact with the mating ring 52 at a sliding surface 55, is provided.
It is slidably supported in the 0 direction. The seal ring 53 is pressed against the mating ring 52 by a spring via a segment seal 56 to maintain the seal. A sealing gas injection port 57 is provided in the casing 54, and steam is injected as a sealing gas. The steam passes through a path indicated by an arrow, passes through a labyrinth seal portion 58 fixed to the casing 54, and enters the blower. By injecting steam having a pressure higher than the internal pressure of the blower into the blower, the leakage of high-temperature gas from the blowers 32 and 34 is prevented.

[0013]

As is clear from the above description, the present invention provides a blower, which has been conventionally sealed with compressed air or nitrogen gas, by using a steam from a steam generator in the system to provide an air compressor. The power can be reduced, and the supply of nitrogen is not required, and the operating cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a fuel cell power generation device of the present invention.

FIG. 2 is a view showing a configuration of a shaft seal of a high-temperature blower.

FIG. 3 is a diagram showing a configuration of a conventional fuel cell power generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel gas line 2 Anode gas line 3 Circulation line 4 Anode exhaust gas line 5 Cathode exhaust gas line 6 Anode exhaust gas reforming line 7 Carbon dioxide gas recycling line 8 Air line 9 Steam line 20 Fuel cell 22 Reformer 23 Catalyst combustor 24 Fuel preheating Device 26 Desulfurizer 28 Turbine compressor 30 Exhaust heat recovery steam generator 32 Carbon dioxide gas recycle blower 34 Anode recycle blower 36 Adiabatic reformer 38 Combustor 40 Air compressor 42 Nitrogen gas supply device 50 Blower shaft 51 Sleeve 52 Mating ring 53 seal ring 54 casing 55 sliding surface 56 segment seal 57 seal gas inlet 58 labyrinth seal

Claims (1)

[Claims] 1. A fuel cell for generating electricity using an anode gas containing hydrogen supplied to an anode and a cathode gas containing oxygen supplied to a cathode, and an anode supplying the fuel gas and steam as anode gas in a reformer to the anode A gas line, an anode exhaust gas reforming line that reforms the anode exhaust gas with an adiabatic reformer and supplies it to the anode, and burns the anode exhaust gas and the cathode exhaust gas with a catalytic combustor to generate combustion exhaust gas and heats the reformer A recycle line for supplying carbon dioxide to the cathode, and a turbine compressor for rotating the turbine with combustion gas produced by burning the anode exhaust gas and the cathode exhaust gas to drive the compressor to generate compressed air and supply the compressed air to the cathode. A steam generator for generating steam from turbine exhaust of a steam generator and supplying the steam to the reformer; The anode exhaust gas reforming line and the carbon dioxide gas recycling line are provided with a recycle blower for injecting gas to seal the shaft, and the shaft heat sealing gas of the exhaust heat recovery steam generator is provided. A fuel cell power generation device characterized by using generated steam.