PHYSICAL-PROPERTIES AND OXIDATION RATES OF CHARS FROM 3 BITUMINOUS COALS

Intrinsic oxidation rates of coal chars derived from three different bituminous coals were measured at 500 degree C and the effects of char formation temperature, conversion, coal particle size and char particle size on the rates were evaluated. Characterization of the various samples including BET surface areas, mercury porosimetry, mercury and helium densities, heating values and in some cases elemental analysis were carried out to better understand the roles and interactions of the various parameters. The results show that apparent and intrinsic rates as well as the heating values are reduced with increasing char formation temperature. N//2-BET surface areas increase an order of magnitude with conversion and exhibit maxima in the range of temperatures considered (1000 K to 1600 K).