Oxy-fuel combustion of coal. Studies on kinetics and mechanism of pressurized combustion

Bituminous coal and lignite samples were carbonized under N-2 at 1000 degrees C for 30 min. The chars were studied for chem. compn., sp. surface, pore structure (N-2 adsorption) and kinetics of combustion under O-2/CO2 (0.1-1.0 MPa) at 500-1000 degrees C (mass loss rate). C conversion degree increased with increasing combustion temp., O-2 concn. and total pressure of the gas phase. The activation energy of the combustion decreased strongly with increasing combustion temp. range and the gas phase pressure. The combustion was diffusion-controlled, esp. at elevated temp. and pressure.