O2/CO2 and O2/N2 combustion of bituminous char particles in a bubbling fluidized bed under simulated combustor conditions

摘要: Most of the time char particles in commercial FB units encounter considerably lower oxygen concentrations than that entrance, say between 2% and 10%, effects oxy-fuel atmosphere on conversion history need to be clearly treated under these conditions. In present work, an experimental study combustion bituminous coal was carried out a laboratory O2/CO2 O2/N2 atmospheres simulated combustor conditions at O2 4–10% v/v, bed temperatures 800–900 °C particle sizes 2–8 mm by continuously measuring CO flue gas. The results indicate is controlled diffusion boundary layer environments gasification limited chemical kinetics. A model, taking into account mass transfer from kinetics char, built, based intrinsic reactivity obtained TGA tests. Simulations, same as experiments, give good agreement terms burnout instantaneous during single particles. Simulated prove low diffusivity CO2 main reason for decreased reaction rate compared with O2/N2. contribution consumption more notable high temperature (900 °C) coarse (8 mm), particularly concentration (4–6% v/v).