Advanced processes for low rank coal drying and dewatering in high efficient power plants

During the combustion of high-moisture lignites ( 50-60 wt.%) in conventional power plants, a substantial amount of the energy content is required to evaporate the water. With a view to secure and strengthen brown coal's position as high available energy source, in recent years many attempts have been made to develop technologies for an energy-efficient drying or dewatering process. In this paper the thermodynamic basics of different processes are analysed. The potential for new lignite fired power plants with efficiencies increased by up to 20% compared to current installations and with CO2 emissions decreased by the same amount is presented.