biomass gasification

syngas production

carbon dioxide

steam gasification

catalytic cracking

chemical looping

heating value

gasification process

Fuel

• The fountain confined conical spouted bed enhances the performance of primary catalysts. • Dolomite and γ-alumina improved syngas composition and reduced tar content. • Olivine and FCC catalysts reduced tar content, but hardly affect syngas composition. • The lowest tar content (5.0 g Nm −3 ) was obtained using dolomite as catalyst. • Light PAHs were the prevailing tar compounds on all the catalysts studied. The performances of the primary catalysts olivine, dolomite, γ-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 °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 γ-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).

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