Effect of thermal upgrading on spontaneous combustion characteristics of western Canadian low rank coals

The results of an experimental study aimed at evaluating the spontaneous combustion characteristics of two western Canadian low rank coals thermally upgraded in steam at varying temperatures are discussed. The spontaneous combustion characteristics of the coals were determined using a method developed at CANMET's Coal Research Laboratory in Devon, Alberta. The liability to spontaneous combustion of the two coals was reduced when thermally treated and further decreased with increase in treatment temperature. The decrease in liability was also found to be a function of loss of both the equilibrium moisture and oxygen-containing functional groups from the coal. The oxygen absorption capacity of the coal was also reduced after thermal treatment.