An Autopsy of Spontaneous Combustion of Lignite

Abstract

The increasing demand of lignite in the power sector has led to a renewed interest to study the possibilities of spontaneous combustion behavior. Bulk storage of lignite with unknown histories of their proneness to self-ignition phenomena has become a concern in their selection. The present evaluation has been directed to delve into the fundamentals of the heat transfer process, to understand the complexity of the spontaneous combustion process, to recognize the multitude influences of moisture as heat and mass transfer agent, and to look into their role in the initiation of coal–oxygen reactions. The roles of moisture and oxygen at various temperature levels have been examined and their possible mechanism has been reviewed. Cause of significant delay to catch fire in the bed of lignite stack even after attaining critical temperature (>70 °C) and some anomalous behavior observed during low-temperature oxidation of lignite has been explained in light of chemical structural parameters.