Accurately predicting the incubation period of spontaneous combustion (IPSC) is of great significance to the prevention of coal self-ignition. In order to overcome the disadvantage of long test period of the adiabatic oxidation methods, in this paper, the composite reaction behavior of coal with oxygen is carried out in a thermogravimetric analyzer under different constant temperature conditions and multiple heating rates (1, 2,4 and 8 Kmin-1) with temperature rising from ambient temperature to 1073K. A novel approach for predicting the IPSC of coal is then proposed. Firstly, based on Starink iso-conversion method and its transformation formulas, the relationships are determined between apparent activation energy, pre-exponential factor and the extent of conversion, as well as the reaction model under different extent of conversion of coal in the water evaporation stage and the oxygen absorption stage. Then, the relationships between temperature and the extent of conversion in the water evaporation stage and the oxygen absorption stage are obtained respectively based on the constant temperature experiments. Finally, the results are substituted into the prediction model which is transformed from Arrhenius equation to calculate the reaction time of coal in the water evaporation stage and the oxygen absorption stage respectively, and the sum of these two parts of time is the IPSC of coal. This approach has the advantages of short test period and good repeatability.
CITATION:Zhong, X X and Hou, F, 2019. A novel approach for predicting the incubation period of spontaneous combustion of coal based on thermogravimetric analysis, in Proceedings Australian Mine Ventilation Conference 2019, pp 222232 (The Australasian Institute of Mining and Metallurgy: Melbourne).