Aiming to under stand biomass-related pyrolysis and gasification processes, which have received particular interests recently due to increasing concerns over fossil fuels and carbon emissions, this work conducts a detailed experimental study of the fluidization characteristics and jet dynamics of biomass mixtures in a fluidized bed. Both single jet and two jets dynamics are investigated, and a parametric study of the influence of particle properties and operational conditions on the dynamic performance of the bed, especially on the jet penetration depth and jet frequency of the binary mixtures, is conducted. Detailed frame-by-frame image analysis coupled with physical parameters reveals many interesting phenomena, which includes multistage flow pattern development and a stochastic nature of jet dynamics, as well as a strong dependence of the jet penetration depth and jet frequency on the bed materials. (C) 2011 Elsevier Ltd. All rights reserved.