The drying characteristics under isothermal condition of Hulun Buir pulverized brown coal with high moisture content of 40% was studied using thermo-gravimetric method. The effects of drying temperature and particle size on drying process were analyzed. The results showed that the constant rate stage was obviously observed

and the characteristics were closely related to drying temperature and free water content. The critical (MCcr) and equilibrium (MCeq) moisture content were obtained. The drying rate decreased with the decrease of particle size

but the effect of particle size was not obvious when the coal particle was enough small. MCcr and MCeq decreased with the increase of temperature

however

MCcr increased and MCeq decreased slightly with the decrease of particle size. The experimental results could provide a basis of selection and optimization of brown coal powder and drying process.