Fuel Impurity Tolerance of Solid Oxide Fuel Cells

Abstract

While SOFCs are the most flexible fuel cells with respect to fuel selection, fuel impurities in practical SOFC fuels can cause degradation of electrodes and thus electrochemical performance. The understanding of fuel impurity poisoning and the increase in tolerance are therefore of technological relevance for SOFC commercialization. Along with thermochemical calculations on the stability of typical fuel impurities under SOFC operational conditions, fuel impurity poisoning of SOFCs is analyzed by using various impurity-containing fuel gases with respect to operational temperature, type and concentration of impurities, fuel composition, and steam-to-carbon ratio. We have revealed that poisoning depends on operational conditions and types of fuels and impurities. The poisoning effect becomes significant for internal-reforming SOFCs operated with humidified methane-based fuels. Poisoning mechanisms are discussed, based on cell voltage and durability data.

Influence of SO2 on the Long-Term Durability of SOFC Cathodes

“…Various degradation mechanisms, however, may appear, such as impurity poisoning, e.g. by H 2 S, affecting the anode performance (1). On the cathode side, chromium can evaporate from metallic components to cathode, leading to cathode degradation (2).…”

Adsorptive hydrogen chloride and combined hydrogen chloride–hydrogen sulphide removal from biogas for solid oxide fuel cell application

“…The effect of chlorine gas in conjunction with SOFC was analysed in several articles. Sasaki et al (2007) published experiments which show that fuel gas containing 5 ppmv of Cl does not cause a cell degradation or voltage drop in the SOFC. Błesznowski et al (2013) investigated the effect of HCl-contaminated fuel gas and concluded that at 10 ppmv a recoverable voltage drop is identified.…”

Removing H2S from Biogas Using Sorbents for Solid Oxide Fuel Cell Applications

“…Poisoning by sulfur compounds occurs generally in the following way: the cell voltage decreases rapidly after adding impurity to fuel gas followed by a quasi‐steady state with a constant cell voltage . In order to use biogas as fuel for a SOFC, several of its components have to be reduced to a certain degree.…”