Combustion behaviour of bituminous and anthracite coal char between 425 and 900 °C

The combustion behaviour of bituminous and anthracite coal char has been studied for temperatures ranging from 425 to 900 °C. The combustion reaction was carried out in a thermogravimetric analyser at 1 atm. A wide range of oxygen partial pressures, from 5×10^?4 to 10^?1 MPa was used. For bituminous char, below 600 °C the intrinsic reaction order and activation energy are 0.75 and 29.0 kcal gmol^?1, respectively, while above 650 °C, the intrinsic reaction order and activation energy are 0.3 and 45.2 kcal gmol^?1. For anthracite char, below 600 °C the intrinsic reaction order and activation energy are 0.9 and 32.8 kcal gmol^?1, while above 650 °C, the intrinsic reaction order and activation energy are 0.3 and 43.6 kcal gmol^?1. The changes in the reaction order and activation energy in the temperature ranges above and below 600 °C imply that the dominant reaction mechanism is different for these two temperature ranges.