The Vrentas-Duda free volume diffusion model has been shown to be a useful formalism by which to examine self- and mutual-diffusion in binary systems. Most industrial drying and separation technologies, however, are based on the transport of multiple components which require the molecular transport process to be described in terms of both principal and cross-diffusion coefficients.

In this work we describe the applicability of a multicomponent diffusion model which was developed on the basis of the average frictional force experienced by a molecule. The model uses self-diffusion coefficients, which can be described by free volume theory, as well as thermodynamic phase equilibria information to predict transport in multicomponent systems. The applicability of the model towards analyzing industrial devolatilization, coating drying, and membrane separations will be discussed.