Assessment of steam gasification kinetics of the char from lignocellulosic biomass in a conical spouted bed reactor

The steam gasification of pinewood sawdust derived char has been studied in a conical spouted bed reactor. The effect temperature (in the 800–900 °C range), steam partial pressure (from 0.2 to 1) and sawdust particle size (0.3–1, 1–2 and 2–4 mm ranges) have on the char gasification kinetics has been determined. The pyrolysis step was performed in situ prior to the gasification step, at the same temperature as that in gasification. Four models have been proposed for the fitting of experimental results, i.e., homogeneous, shrinking core, nth order and random pore models, with the latter providing the best results. The activation energy obtained from the fitting is 190 kJ mol⁻¹ and the reaction order with respect to steam partial pressure (α) is 0.344. - Highlights: • The effect of main operating conditions have on gasification kinetics were analysed. • An increase from 800 to 900 °C reduces gasification time to one-sixth. • Particle size kinetic limitations on char gasification rate are negligible below 2 mm. • Four models are used: homogeneous, shrinking core, nth order and random pore model. • F tests show that nth model and RPM (random pore model) suitably fit conversion data.