Hydrogen production by biomass gasification in a supercritical water fluidized bed reactor: A CFD-DEM study

•CFD-DEM study of biomass gasification in a SCW fluidized bed was conducted.•Reactions affected the fluidization mainly by the endothermic effect.•Low flow rate, high wall temperature and initial bed height favored gasification.•The results are very useful for the operation and design of SCW fluidized bed.