ABSTRACT
Fuels with high moisture content, such as low rank coals (LRCs) and some kinds of biomass, are playing an important role in the current global energy market. Total proved reserves for LRC worldwide, including subbituminous and lignite, are 316.7 billion tonnes, accounting for about 30.6% of total coal reserves at the end of 2017. Spontaneous ignition of coal occurs naturally without external source of heat as a result of low temperature oxidation. The self-heating is dependent on several factors, such as power plant management, transport management and stockpile storage in silos, bunkers and mills. Devolatilization of coal is a process in which coal is transformed at an elevated temperature to produce gases, tar and char. Drying of lignite prior to combustion will inevitably induce devolatilization. Drying temperature is key parameter that determines devolatilization. The residue moisture content of lignite after drying is close to that of bituminous coal, and its combustion characteristics are important for the design of lignite boilers.
