Biogas use in high temperature fuel cells: Enhancement of KOH-KI activated carbon performance toward H2S removal

The results revealed a positive role of water (up to 90% of relative humidity (R.H.)) for different gas matrices, enhanced by the simultaneous presence of small percentages of oxygen (2%v). A relevant influence of gas matrix composition was found (except for the case of oxygen addition to dry inlet streams), specifically in terms of a marked negative effect of CO2 and a significant sorption capacity increase for high percentage of methane. Sulfur dioxide was not detected in the outlet gas-phase for the investigated operating parameters (O2 2%v, R.H. 0-90%, H2S 100 ppmv, temperature 45 °C). Therefore, even in the case of further oxidation of adsorbed elemental sulfur to SO2, this product could be completely removed by AC KOH-KI.