ABSTRACT This work presents the results of experiments conducted to determine the mass loss and size reduction characteristics of a cylindrical wood particle undergoing devolatilization under oxidation conditions in a bubbling fluidized bed combustor. Cylindrical wood particles having five different sizes ranging from 10 to 30 mm and aspect ratio (l/d=1) have been used for the study. Experiments were conducted in a lab scale bubbling fluidized bed combustor having silica sand as the inert bed material and air as the fluidizing medium. Devolatilization time, and radial and longitudinal shrinkages have been measured during and at the end of devolatilization. Studies have been carried out at three different bed temperatures (T bed =750, 850 and 950 °C), two inert bed material sizes (mean size d p =375 and 550 µm) and two fluidizing velocities (u=5u mf and u=10u mf ). Devolatilization time is most influenced by the initial wood size and bed temperature. Longitudinal shrinkage begins after 50% of conversion while radial shrinkage occurs right from the beginning. There was no clear influence of the fluidization velocity and bed particle size on the parameters studied
