BIO-OIL Steam Gasification in a Fountain Confined Spouted BED

The combination of delocalized units for the fast pyrolysis of biomass to produce bio-oil followed by centralized units for the gasification of bio-oil appears as an economically attractive option for the full-scale production of syngas because transportation of bio-oil is less costly than that of biomass. This study deals with the use of the conical spouted bed reactor (CSBR) as a hybrid technology. Thus, bio-oil is first produced by fast pyrolysis under the conventional spouting regime and this liquid is then converted into syngas using steam as gasifying agent under the fountain enhanced spouting regime. This strategy is an interesting alternative to direct biomass gasification, as the cost-effective transport of bio-oil could make the implementation of this biomass valorization route profitable. Furthermore, this paper assesses the suitability of a bio-oil feeding device developed by our research group made up of of a line-thermostated at 60-80 ºC and a non-atomizing injector cooled by water. The bio-oil was produced at 500 ºC in the CSBR operating under conventional spouting, and collected in the condensation system. It was then gasified in the CSBR operating under fountain enhanced regime. The effect of temperature (800, 850 and 900 ºC) on the gasification performance was assessed. An increase in gasification temperature improved process efficiency in terms of syngas production and tar reduction, with the maximum carbon conversion efficiency being 96.3 % at 900 °C. Besides, the hydrogen content also increased with temperature from 4.51 wt% at 800 °C to 7.96 wt% at 900 °C on a dry basis, which resulted in an increase in H₂/CO ratio from 1.2 to 2, respectively, which are within the range required for GTL processes. Moreover, tar content decreased by around 70% in the 800–900 °C range, recording the lowest value (12.7 g/Nm³) at 900 °C.