Lignite upgrading refers to the process of removing wax, free humid acid and water out of the lignite by organics like methylbenzene and high temperature respectively. Actually speaking, the lignite upgrading is a dehydration process. The commonly-used method around the world for dehydration is by using the lignite coal dryer. The upgraded lignite is more easy to be used, transported and stored. After the repeated experiments, the upgrading technologies for lignite, with hot smoke as heating medium, combine the advantages of fluidized bed and rotary drying together.
