Limiting factors for planar solid oxide fuel cells under different trace compound concentrations
By Davide Papurello and Andrea Lanzini and Davide Drago and Pierluigi Leone and Massimo Santarelli
Published in Energy
2016
Abstract
The present work investigates the performance of anode supported solid oxide fuel cells under the influence of different trace compounds. \EIS\ (Electrochemical impedance spectroscopy) has been used to deconvolute the impedance spectra of an \SOFC\ (Solid Oxide Fuel Cell) in order to identify the main losses. The impact of single and double contaminants on the \SOFC\ performance has also been investigated. Typical biogas trace contaminants, obtained after a clean-up stage, such as sulfur, chlorine, aromatic compounds and siloxanes, have been taken into consideration. The results show how the ohmic contribution is almost independent of the \H2S\ concentration. \H2S\ acts mainly on the polarization losses and especially on the mass transport resistance. The impact of \HCl\ on the \SOFC\ performance is mainly connected to the charge transfer process. D4, as the model compound for siloxanes, already acts on \SOFC\ performance at ppb(v) levels. The polarization losses have been influenced the most, and the largest increase has been recorded for the low frequency term, Rlow, related to the mass transport resistance for naphthalene and toluene. H2S, introduced with other contaminants, causes the instantaneous deterioration of the \SOFC\ performance and the more the types of contaminants co-fed to the SOFC, the larger the initial anode degradation.