Behaviour of primary catalysts in the biomass steam gasification in a fountain confined spouted bed

The performances of the primary catalysts olivine, dolomite, gamma-alumina and FCC spent catalyst were evaluated in the continuous steam gasification of sawdust in a bench-scale plant equipped with a fountain confined conical spouted bed reactor. The experiments were carried out at 850 degrees C, and the efficiency of the gasification process was defined by gas yield, H-2 production, tar concentration and composition, and carbon conversion efficiency. The benefits of the fountain confiner not only helped to improve the gas-solid contact, and therefore favoured the primary catalysts' reforming and cracking activity, but also enhanced H-2 production and reduce tar formation. Thus, dolomite and gamma-alumina recorded the lowest values of tar, 5.0 and 6.7 g Nm(-3), respectively, which corresponded to 79% and 72% tar reduction compared to the inert sand, whereas olivine and the FCC spent catalyst recorded higher tar contents, 20.6 and 16.2 g Nm(-3), respectively. It is noteworthy that light PAHs were the most abundant species in the tar (60 wt% of the whole tar content).