Hydrodynamics plays a crucial role in defining the performance of gas-solid circulating fluidized beds (CFBs). In this study, a typical biomass particle, sawdust, was selected as the bed materials to experimentally investigate its fluidization characteristics in a cold model circulating fluidized bed. The column was 10 m in height and 280 mm in diameter, and was equipped with 12 differential pressure transducers to measure axial pressure drop along the riser. A reflective optical fiber probe was employed to measure local solids holdup and local particle velocity. The effects of operating conditions on axial and radial distributions of solids holdup and particle velocity were analysed. The flow structure of sawdust in CFB was compared with that of FCC and sand particles. The results show that the shapes of the sawdust solids holdup and particle velocity distributions are similar to those of FCC and sand particles, though their typical operating conditions are quite different because of different particle properties and reactor geometries. (c) 2011 Elsevier B.V. All rights reserved.