Study on the drying kinetics of lignite under negative pressure

Drying behaviors of lignite were studied with a vacuum drying oven under different pressures and temperatures in this study.A mathematical model was established according to the curves of the water content for different drying times to explain the kinetics of lignite drying.Further analysis explained the influence of pressure and temperature on final moisture content.The result suggests lower pressure and higher temperatures cause smaller final moisture contents，which indicates the existing of abundant blind holes in coal and the pressure and temperature gradients should be large enough to rupture the blind holes.