MATHEMATICAL MODELLING OF ROTARY DRYING OF WOODY BIOMASS

Rotary drying is an effective method to dry small sized solid materials, because of the enhanced contact between the solids and hot air by the lifting actions of the dryer flights. Rotary drying is also a complicated process as the operation involves physical motions of the solid materials in the dryer as well as the heat and mass transfer. Woody biomass in the form of forestry industry residues has been recognized as a promising resource for renewable energy and liquid fuels. Drying of the woody biomass is one of the key operations in development of the energy conversion technologies. This project has developed a mathematical model to simulate the woody biomass drying in a rotary dryer, based on energy and mass balance and transfer, correlation of residence time, and drying kinetics of the thin wood sheets. The model was applied both for co-current and counter-current rotary dryers, and the simulation results are consistent with the observed trend. However the accuracy of the model needs to be further investigated through experimental drying tests.