Simulation of alternative fuels for potential utilization in solid oxide fuel cells

Abstract

Fuel cells are promising with advantages of higher energy conversion efficiency and lower emissions of SOX, NOX, and CO2 than conventional power systems. Solid oxide fuel cell (SOFC) is a high temperature fuel cell, which operates at 873–1273 K. This allows SOFCs to operate with different types of fuels from both fossil and renewable sources because of their general higher tolerance to contaminants than other fuel cells. It opens up for an easier transition from conventional power generation of hydrocarbon-based fuels to hydrogen energy by fuel cells. With increased interest in the use of renewable fuels, fuel cells have the potential to play a significant role in a sustainable solution. Attractive fuels, which are reviewed here and analyzed through thermodynamic calculations in this study, are methanol, ethanol, di-methyl-ether, and biogas. It is concluded that it is feasible for SOFCs to handle all the studied fuels. Further, a CFD model of an anode-supported SOFC is simulated with biogas as fuel. An analysis of the fuels is conducted at 1000 K, in terms of the heat required for each mole H2 converted. It shows that methane uses twice as much heat as methanol and di-methyl-ether do, and if efficiently distributed where needed, it can work as a possible performance enhancement. A composed table of comparable studies in the literature of different alternative fuels is provided. The case study of an anode-supported SOFC fueled with biogas of varying amount of methane and steam-to-fuel ratio revealed that biogas needs a high inlet temperature to enable the reforming and keep a constant current density distribution. Copyright © 2011 John Wiley & Sons, Ltd.