Vibration drying of lignite based on the thermal fragmentation property and its prediction model

A lignite vibrating mixed-flow screening and drying system was implemented in this study. Vibration is conducive to heat and mass transfer between the hot carrier gas and lignite particles and prompts large particles into small particles based on their thermal fragmentation to improve the drying efficiency. During the vibration drying process, most or all of the large particles were broken into smaller particles, and there was always a clear moisture gradient with respect to the particle size fractions. The particle size-remaining moisture gradient (M-s) was defined to describe the nonuniformity of the dryness among different size particles based on their mass content. M-s increased first and then decreased with drying time, and a high drying rate usually resulted in larger differences in moisture among the products, whereas a lower residual moisture content reduced the differences. The Weibull model was suitable for describing and predicting the vibration drying kinetics of lignites. Based on the results of this study, a vibration drying pilot system will be designed and set up to obtain a new drying system.