Reaction kinetics of coal oxidation at low temperatures

Adiabatic oven testing of coal to assess the propensity for self-heating produces data on the kinetics of the coal oxidation reaction. Repeat tests on the same coal at different starting temperatures ranging from 20 to 57 °C shows that there is a strong time-temperature effect on the reaction kinetics. At these low temperatures the initial reaction rate is predominantly non-Arrhenius, but converges to Arrhenius behaviour at temperatures above 70 °C. A new rate equation model has been derived that accounts for the change in kinetic behaviour in the low temperature region. This model is based on the concept of reactive site availability.