The direct carbonate fuel cell technology: advances in multi-fuel processing and internal reforming

Carbonate fuel cells are new generation of power plants that provide electricity at very high efficiency and low environmental emissions. The direct carbonate fuel cell (DFC(TM)) technology is fast approaching its commercial entry. DFC cell operates on a variety of hydrocarbon fuels such as natural gas, biogas, coal gas, diesel and LPG. Conventionally, an external reformer is used to supply hydrogen-rich gas to fuel cell. FuelCell energy's DFC(TM) technology has adopted an internal reforming approach that eliminates the need for an external reformer, resulting in increased efficiency, compactness, better thermal management and lower cost. Fuel processing operation in DFC(TM) technology varies based on the nature of fuel. However, the fuel thus supplied to the fuel cell has a two-step refinement approach involving impurities (sulfur) removal followed by pre-reforming desulfurized fuel to knock out higher hydrocarbons. Methane-rich gas obtained from pre-reformer is thus fed into fuel cell for internal reforming to produce hydrogen in DFC stacks, thereby producing DC power. At each stage of this operation, catalysts are used to facilitate production of desirable fuel cell fuel. FCE has developed stable catalyst system at each one of these steps. FCE's experience with internal reforming (indirect internal reforming and direct internal reforming catalysts) and fuel processing catalysts is discussed here. (C) 2002 Published by Elsevier Science B.V.