Experimental Investigation into the Spontaneous Ignition Behavior of Upgraded Coal Products

The propensity for spontaneous ignition of nine coal samples and their upgraded products were experimentally investigated. The basket method was used to study the effects of the variation of mineral matter and volatile content on the spontaneous ignition of coal. The removal of mineral matter by chemical leaching caused the spontaneous ignition temperature (SIT) to decrease, which indicated a higher propensity for ignition. As the mineral matter increased, SIT increased approximately linearly. The results indicated that the SIT of coal char first decreased with a decreasing volatile content and then rapidly increased as the volatile content continued to decline, because of the deepening of the devolatilization. This paper proposes a prediction model based on the oxygen and carbon ratio (O/C) parameter in raw coal, which can be used to predict its SIT.