Compared to the low temperature air drying process,the high temperature flue gas drying of lignite has advantages of reduction of fire and explosion hazards as well as improving drying efficiency.Therefore,the parameters (gas temperature,particle size,initial water ratio) that affect the drying process of a single particle were studied.Moreover,the drying curves,the drying rate curves and the surface temperature curves of particles under different initial gas temperature,particle size and initial water ratio were obtained by experiments.It is found that the drying rate of the high temperature (≥600 ℃) flue gas is beyond that of the low temperature (≤200 ℃) air significantly.But the further rise of the gas temperature has only a very weak influence on the critical water ratio and the drying rate when comparing with the low temperature air drying.With the increase of initial water ratio,the drying rate increases,whereas the surface temperature decreases.Besides,a smaller particle size exerts much more influence on the drying rate and critical water ratio than the gas temperature and initial water ratio.