Drying characteristics of low rank coals in a pressurized flash drying system

Drying characteristics of low rank coals were examined and determined using a pressurized flash drying system which consisted of a pressurized feeder, rolled tubes (maximum of 6 m), a cyclone, and a back pressure regulator. The effect of the operating conditions, such as pressure (maximum of 40 bar), gas outlet temperature (maximum of 300 °C), particle sizes (212-300 and 300-355 μm) and residence time (maximum of 1 s) on the drying ratio was investigated and analyzed. The study results show that temperature is a more effective factor than pressure. A correlation equation to predict the drying ratio of coals was suggested based on operation conditions.