Reactivity of Biomass Chars from Mozambique in a Fluidized Bed Combustor

Abstract

Wood samples of Mozambican origin were carbonized in a flow of nitrogen at temperature of 850 ºC. The obtained vegetable chars were crushed and burned in batches of 1.5 g in a bubbling fluidized bed (at 1.5Umf) to obtain the kinetic and mass transfer data. Batches of char particles with an average diameter in the range 1.6-3.6 mm were tested in a bed of silica sand with 283 μm average diameter, for the range of temperatures 750-900 ºC. The results showed that the fragmentation phenomena were not relevant and no effect of bed agglomeration was observed for the tested chars, in spite of their higher reactivity when compared with other wood chars. Sherwood numbers and kinetic constants of the chemical reaction were determined and are presented as correlations, which can be used to predict these parameters both for design and for CFD-based simulations purposes.