Trace compounds impact on SOFC performance: Experimental and modelling approach

Issues related to SOFCs performance and durability are strictly dependent on the feeding fuel quality. SOFC capability to be fed with fuels different from hydrogen opens to scenarios in which a big variety of fuels can be used at the aim. Unfortunately, problems related to anode deactivation due to the contaminants presence can arise. The present work investigates the performance of anode supported solid oxide fuel cells in case of co-feeding of different trace compounds. Electrochemical impedance spectroscopy is the investigation technique used to analyze the impedance spectra. Typical biogas from OFMSW trace contaminants that follow an initial failure in the cleaning system, such as sulphur, aromatic compounds and siloxanes, have been simultaneously tested. Tests showed that the most deleterious impact for the SOFC was due to the H2S action. This influences mostly the electrochemical losses respect to diffusion losses, even if this last are not null and can be accounted as a secondary effect. On the contrary, the co-presence of D4 and H2S mitigates in the short-term the effect that the only D4 produces when fed with biogas. The most relevant consequence produced by C7H8 was recorded in the low frequency of Nyquist plot, affecting mainly the mass transport phenomena. Experimental tests are accompanied by the implementation of the fuel cell model through COMSOL Multiphysics software to study the effect of pollutants on fuel cell performance.