Main issues of the impact of tar, H2S, HCl and alkali metal from biomass-gasification derived syngas on the SOFC anode and the related gas cleaning technologies for feeding a SOFC system: A review

Biomass gasification has acquired considerable interest as a sustainable and environ- mentally friendly way to produce heat, hydrogen or electricity from agro-industrial wastes or other kinds of biomass. A very effective solution for the achievement of high electrical efficiency (up to 55%) is the integration of biomass gasification with solid oxide fuel cell (SOFC) technology, including the necessary gas cleanup to avoid degradation of the SOFC. For this reason, this paper first shows in detail the risk and the impact of carbon deposition, exposure to tar, hydrogen sulphide, hydrogen chloride and alkali metals on SOFC anode and then, considering the tolerance limit for inorganic and organic contaminants (<1 ppmv for H2S, HCl and alkali and <10 ppmv for tar), offers an overview of the most relevant and effective technologies to remove these contaminants and to feed safely a SOFC system.