Tubular solid oxide fuel cell/gas turbine hybrid cycle power systems: Status

The solid oxide fuel cell (SOFC) is a simple electrochemical device that operates at 1000degreesC, and is capable of. converting the chemical energy in natural gas fuel to AC electric power at approximately 45% efficiency (net AC/LHV) when operating in a system at atmospheric pressure. Since the SOFC exhaust gas has a temperature of approximately 850degreesC, the SOFC generator can be synergistically integrated with a gas turbine (GT) engine generator by supplanting the turbine combustor and pressurizing the SOFC, thereby enabling the generation of electricity at efficiencies approaching 60% or more. Conceptual design studies have been performed for SOFC/GT power systems employing a number of the small recuperated gas turbine engines that are now entering the marketplace. The first hardware embodiment of a pressurized SOFC/GT power system has been built for Southern California Edison and is scheduled for factory acceptance tests beginning in Fall 1999 at the Siemens Westinghouse facilities in Pittsburgh, PA. The hybrid power cycle, the physical attributes of the hybrid systems, and their performance are presented and discussed.