The effect of pyrolysis heating rate on the steam gasification reactivity of char from woodchips

Abstract

Abstract This work, performed in the context of Gaya project, focuses on the characterization and modelling of the effect of the pyrolysis heating rate on the steam gasification of char from woodchips. An experimental work was performed based on thermogravimetry and solid characterization of char samples prepared under different conditions. The results showed that gasification apparent reactivity increased with the increase of heating rate. The faster chemical kinetics of char prepared under high heating rate could be related to its higher catalytic inorganic content together with a more reactive carbonaceous structure. The increase of heating rate favours porosity development and the enlargement of pores, which would have a positive effect on gasification reaction rate by enhancing gas diffusion within the solid. The effect of heating rate on char gasification was included in a model previously developed, by correlating the chemical kinetics, particle density and diffusion rate to the char yield, which was selected as a suitable indicator of the heating rate. The new version of the model, considering the variability of heating rate during char formation, was validated through accurate predictions of the experimental results.