H 2 -enriched gaseous fuel production via steam-gasification of biomass by using lime-based sorbents

The main objective of the present study was to compare the catalytic activity of selected limestones (Göynük, Dikmen, Polatlı Yolu, Kınık Tüneli and Köserelik) in terms of H2-rich syngas production from biomass gasification. In order to achieve this goal, an ASPEN plus-based model for biomass gasification integrated with carbonation reaction was developed. Tar formation was also considered and the gasification process was carried out based on Gibbs free energy minimization. A combined effect of temperature (600-710 °C), steam/biomass ratio, S/B (0.58-1.58), and limestone/biomass ratio, L/B (0-2.0) on gas composition, H2 yield (HY) and gas yield (GY) was also studied. An increase in both S/B and L/B was beneficial for H2 enrichment. The CO2 content declined sharply from 16.83 vol% to 10.28 vol% with increasing L/B from 0 to 1.5; however, a marginal reduction in CO2 content was observed with further increase in L/B. The highest HY (51.01 g/kg) was produced with Dikmen followed by Göynük, Polatlı Yolu, Kınık Tüneli and Köserelik. The results also showed that the limestone samples with high CaO content in general exhibits a better H2 production capacity than limestones with low CaO content. To the best of our knowledge, no simulation study has been presented to compare the catalytic activity of different limestones in terms of H2 production.