Due to its renewable characteristics, biomass is potentially important to energy conversion processes. Fluidized beds are involved in many processes related to energy conversion of biomass. Hence, detailed insight on the hydrodynamics of biomass fluidized beds is crucial for successful energy conversion as well as to better design and scale-up of fluidized bed reactors. The present work focuses on modeling the mixing and segregation behavior of biomass mixtures in a fluidized bed. Different effects, such as mixture composition, particle size, and superficial gas velocity, on the mixing and segregation are simulated and the results are compared to measurements obtained using X-ray computed tomography. Furthermore, side injection of biomass particles into a fluidized bed is also studied and compared with visual observations. A comparison between the numerical simulations and measurements shows good agreement. (C) 2012 Elsevier B.V. All rights reserved.