An experimental investigation on the drying characteristics and kinetics of Baorixile lignite in a fixed bed

This study investigates the effects of drying treatment on coal composition, function groups, pore structure, and drying characteristics of Baorixile lignite in an independently developed fixed bed with high sealing performance. The variation of functional groups of lignite during the drying process is determined by Fourier Transform Infrared spectroscopy and chemical quantitative analytical method, the pore structure is analyzed by Scanning Electron Microscope and nitrogen adsorption, and the drying characteristics is discussed by using isothermal and Non-isothermal method, respectively. The results show that the dehydration rate has a significant linear correlation with the atomic ratio (H/C + O/C) in the isothermal drying process of lignite. The dehydrating characteristics at different temperatures and different time periods indicate there are three stages in isothermal drying process. Two different dynamic models are evaluated for the kinetic equation in non-isothermal process, and the results show that Dolye method was more agree with experimental data. The continuous increasing of pore size causes to the decreasing of the specific surface, and the pore volume was mainly contributed by the pores of 20-56 nm during the drying process of lignite.