Most published models of pneumatic dryers refer to Single Particle Models where the particle is a lumped parameter object. This work presents a model of flash dryer where drying kinetics is obtained by solving transport equations inside a particle. in addition a schematic of a set-up for sorption isobar measurement necessary for understanding equilibrium of wet solid in superheated steam and drying simulation together with results of sorption isobar determination for willow Salix viminalis are presented.