Treatment of Biogas for Feeding High Temperature Fuel Cells

Investigation of NH3 Influence on Adsorptive H2S Removal from Biogas for Solid Oxide Fuel Cell Application

“…Apart from activated carbons and metal oxides, zeolites facilitate desulfurization at ambient temperature and moderate pressures . Zeolites are crystalline, hydrated aluminosilicates with a defined lattice structure which contains exchangeable alkali metal or alkaline earth metal cations.…”

“…Depending on the origin of the biogas, these impurities may vary in a wide range. For example, the amount of H 2 S, the most dominant biogas pollution, varies from less than 100 ppmv in gas produced out of animal waste up to 10 000 ppmv in gas originating from food waste . Tab.3 points out the difference between a landfill gas and an anaerobic digester gas.…”

“…Depending on its production source and the stage of the upgrading process, biogas can contain a number of sulfur compounds that have the capability to corrode processing equipment and gas pipelines, to inhibit the performance of vehicle catalysts, and to damage fuel cells . Various researchers investigated the influence of sulfur compounds on fuel cell efficiency and concluded that sulfur compounds are the dominant poison .…”

“…Since the extent and nature of cell degradation are linked to used cell materials and microstructural characteristics, the phenomenon of cell degradation cannot be generalized. Turco et al assumed that any kind of sulfur compound has to be reduced to a level of < 1 ppmv to ensure long‐term performance of the SOFC .…”

“…As mentioned before, sulfur compounds form the group with the highest poison potential. Due to the high operating temperatures of SOFCs, sulfur compounds decompose to H 2 S . Hagen et al reported a significant degradation of cell voltage in the presence of 2 ppmv H 2 S in the feed gas .…”