Experimental study on the dehydration characteristics and evolution of the physicochemical structure of XilinGol lignite during the dehydration process

•The initial stage of lignite dehydration is determined as a constant acceleration of moisture release.•The effects of time and particle size on drying characteristics were investigated.•Dehydration time has little effect on the occurrence of structural water in lignite.•Pore structure and surface oxygen content are affected by dehydration time.