High efficiency carbonate fuel cell/turbine hybrid power cycles
- Energy Research Corp., Danbury, CT (United States)
Carbonate fuel cells developed by Energy Research Corporation, in commercial 2.85 MW size, have an efficiency of 57.9 percent. Studies of higher efficiency hybrid power cycles were conducted in cooperation with METC to identify an economically competitive system with an efficiency in excess of 65 percent. A hybrid power cycle was identified that includes a direct carbonate fuel cell, a gas turbine and a steam cycle, which generates power at a LHV efficiency in excess of 70 percent. This new system is called a Tandem Technology Cycle (TTC). In a TTC operating on natural gas fuel, 95 percent of the fuel is mixed with recycled fuel cell anode exhaust, providing water for the reforming of the fuel, and flows to a direct carbonate fuel cell system which generates 72 percent of the power. The portion of the fuel cell anode exhaust which is not recycled, is burned and heat is transferred to the compressed air from a gas turbine, raising its temperature to 1800{degrees}F. The stream is then heated to 2000{degrees}F in the gas turbine burner and expands through the turbine generating 13 percent of the power. Half the exhaust from the gas turbine flows to the anode exhaust burner, and the remainder flows to the fuel cell cathodes providing the O{sub 2} and CO{sub 2} needed in the electrochemical reaction. Exhaust from the fuel cells flows to a steam system which includes a heat recovery steam generator and stages steam turbine which generates 15 percent of the TTC system power. Studies of the TTC for 200-MW and 20-MW size plants quantified performance, emissions and cost-of-electricity, and compared the characteristics of the TTC to gas turbine combined cycles. A 200-MW TTC plant has an efficiency of 72.6 percent, and is relatively insensitive to ambient temperature, but requires a heat exchanger capable of 2000{degrees}F. The estimated cost of electricity is 45.8 mills/kWhr which is not competitive with a combined cycle in installations where fuel cost is under $5.8/MMBtu.
- Research Organization:
- USDOE Morgantown Energy Technology Center (METC), WV (United States)
- OSTI ID:
- 426101
- Report Number(s):
- DOE/METC-96/1024; CONF-9510272-; ON: DE96000644; TRN: 96:006563-0003
- Resource Relation:
- Conference: Workshop on very high efficiency fuel cell/advanced turbine power cycles, Morgantown, WV (United States), 19 Oct 1995; Other Information: PBD: 19 Oct 1995; Related Information: Is Part Of Proceedings of the workshop on very high efficiency fuel cell/gas turbine power cycles; Williams, M.C.; Zeh, C.M.; PB: 92 p.
- Country of Publication:
- United States
- Language:
- English
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