• Number 328  |
• January 10, 2011

NETL explores solid oxide fuel cells

DOE's National Energy Technology Laboratory has been conducting research to improve the cost effectiveness and efficiency of solid oxide fuel cells (SOFCs). Recent laboratory tests conducted at NETL have focused on quantifying exposure thresholds for hydrocarbons (benzene and naphthalene) and process chemicals. Through carefully controlled 500-hour tests where standard SOFCs were exposed to simulated synthesis gas environments containing precise trace material concentrations, the maximum exposure limit for benzene was determined to be 150 ppm, and the maximum acceptable exposure to naphthalene was 110 ppm. Collected electrochemical impedance data indicate that at higher concentrations of benzene and naphthalene, resistances associated with lower frequency processes (such as mass transfer) increased, which implies that the fuel gas was encountering resistance as it traveled to the reaction sites within the anode. Post-operational microscopy and spectroscopy were performed on the cells exposed to benzene and naphthalene to search for physical degradation. Evidence of anode particle growth in hydrocarbon exposed samples (especially for naphthalene) has been detected, but no signs of carbon deposition were recorded.

Selexol, which is a promising material for CO2 removal from coal plants, has not been observed to accelerate degradation at exposures of 3.5 ppm, and therefore remains a viable option for SOFC applications as well.

[Linda Morton, 304.285.4543
Linda.morton@netl.doe.gov]