Combustion property and kinetics of fine chars derived from fluidized bed gasifier

The combustion properties of 3 fine chars derived from fluidized bed gasification of coals with different rank were studied in a thermogravimetric analyzer (TGA). In addition, the influence of ash on combustion reactivity was investigated, and the processes were analyzed using three kinetic methods to obtain the kinetic parameters. The results suggest that the existence of volatile in fine char from low-rank lignite reduces its ignition temperature, while the decomposition of inherent minerals at relatively high temperature leads to a second peak in the DTG curve. The ashes of fine chars have an inhibiting influence on burn-out ability and comprehensive combustion reactivity. The kinetic analysis indicates that the activation energy increases with the increasing burnout extent. Compared with Coats-Redfern and Ozawa-Flynn-Wall methods, the Vyazovkin method fits the experiment results best.