Steam gasification of biomass in a conical spouted bed reactor with olivine and γ-alumina as primary catalysts

Olivine and γ-alumina have been used as primary catalysts for tar elimination in the continuous steam gasification of pine wood sawdust in a bench-scale plant provided with a conical spouted bed reactor. A comparison of the performance of each catalyst with that observed for a bed made up of inert silica sand shows that both catalysts have a significant activity for tar cracking/reforming, given that the amount of tar obtained by operating with beds of inert sand is reduced by 79% and 84% when olivine and γ-alumina are used, respectively. The tar cracking reduces selectively the content of light and heavy PAHs, giving way to an increase in the concentration of light aromatics. Furthermore, both catalysts cause a positive effect on the gas composition by slightly enhancing the water–gas shift and reforming reactions.