HIGH-TEMPERATURE FUEL-CELLS FOR POWER-GENERATION

Hybrid systems consisting of series-connected high-temperature solid-electrolyte fuel cells (HTSEFCs) thermally coupled to coal gasifiers show great potential for overall efficiencies of nearly 60% for the production of electricity from coal. This paper describes a steady-state model for the prediction of HTSEFC voltage, current and power density. The HTSEFC model is essentially a distributed parameter electrical network that includes the effects of mass transfer resistance (concentration polarization), chemical kinetic resistance (activation polarization), as well as all relevant electrical resistances (ohmic losses). This electrical network representation leads to a finite-difference discretization which, in effect, divides the fuel cell into many simple current-flow sections. Furthermore, the model computes the fuel and oxidant stream compositions as functions of axial length from energy and mass balances performed on each fuel cell slice. The model yields results that compare favorably with the published experimental data from Westinghouse.