Prediction of yields and composition of char from fast pyrolysis of commercial lignocellulosic materials, organosolv fractionated and torrefied olive stones

•Fractionation of olive stones was optimized using a novel organosolv method.•Fractionated biomass was for the first time reacted in a wire mesh reactor.•Char yields and morphology were strongly affected by fractionation conditions.•Model gave the best predictions of char yield for 180 °C fractionated components.