97/02126 Combustion kinetics of coal chars in a fluidized bed

Abstract

Char combustion has been studied in an electrically heated, 78 mm diameter laboratory fluidized bed combustor. The parent coals were lignite, brown coal and anthracite. The experiments were carried out at bed temperatures of 500--800 C, superficial velocities of 0.44--0.53 m/s and particle diameter of 5--15 mm. Bed temperature and O{sub 2}, CO and CO{sub 2} concentrations were continuously measured during combustion. Char particle temperature was calculated using Baskakov heat transfer correlation. Adopting shrinking particle combustion model, kinetic parameters were estimated. Burning times were estimated, based on the determined kinetic parameters and the particle temperatures, and compared with char burning times based on the off gas analysis.