The influence of the drying medium on high temperature convective drying of single wood chips

摘要

High temperature convective drying of single wood chips with air and superheated steam respectively is studied theoretically. The two-dimensional model presented describes the coupled transport of water, vapour, air and heat. Transport mechanisms included are the convection of gas and liquid, intergas as well as bound water diffusion. In the initial part of the drying process, moisture is transported to the surface mainly due to capillary forces in the transversal direction where evaporation occurs. As the surface becomes dry, the drying front mover towards the centre of the particle and an overpressure is simultaneously built up which affect the drying process.