A comparison of spontaneous combustion susceptibility of coal according to its rank

This study investigated spontaneous combustion susceptibility of coal according to the rank. To estimate the spontaneous combustion susceptibility of coal, both crossing-point temperature (CPT) measurement and gas analysis by using gas chromatography (GC) were performed. For the experiment, Eco coal and Kideco coal, Indonesian lignite, and Shenhua coal that is Chinese bituminous coal were used. The lignite such as Eco coal and Kideco coal contains more functional groups that easily react to oxygen more so than Shenhua coal. For this reason, the lignite is more easily oxidized than bituminous coal at low temperature, which results in high O2 consumption, increase in CO and CO2 generation, and low CPT. Although the CPT of Eco coal and Kideco coal is identical to each other as they are the lignite, Kideco coal has a lower initial oxidation temperature (IOT) and maximum oxidation temperature (MOT) than those of Eco coal. This means that although each coal has the same rank and CPT, spontaneous combustion susceptibility of coal may vary because the initial temperature of the coal at which oxidation begins may be different due to the substances that participate in oxidation.