Short-cut calculation for non-isothermal drying of shrinking and non-shrinking particles and of hollow spheres containing an expanding central gas core

A procedure is presented for the calculation of non-isothermal drying rates of shrinking and non-shrinking particles of different geometries including rectangular bodies, cylinders, spheres and hollow cylinders and spheres. The implication on drying rate of changes in volume of the gas bubble in hollow spheres is taken into account. Starting point are the experimentally observed isothermal drying rates versus fraction water removed of a slab of the material of interest at two temperature levels. With the aid of a short cut calculation method based on the exact numerical computer solutions of the diffusion equation valid for concentration dependent diffusion coefficients and complex boundary conditions the information obtained from the isothermal slab drying experiments is transformed to other geometries and non-isothermal conditions.