DRYING AND DEPOSITION IN A MULTIPHASE MULTICOMPONENT MEDIUM: AN EXPERIMENTAL ANALYSIS AND A NEW MODELLING APPROACH

Abstract

This paper deals with the drying of a multiphase multicomponent medium, which is initially fluid and contains a solid component, some water and a soluble component. An experimental approach of the physical phenomena in such a medium during drying is first carried out in terms of water and soluble component transport. In this aim, drying experiments have been realised and lead to the determination of drying kinetics, time evolution of moisture content profiles and soluble component profiles during the drying. These experiments allow us the proposition of a mass transfer descriptive model. This model is based on a diffusive approach of the convective fluid phase transport. Mutual diffusion of the dissolved part of the soluble component into this fluid phase, deposition process of the dissolved part by crystallisation, and shrinkage of the medium during drying are also taken into account. By using this model and the experimental results, a simple identification of both the time and the spatial average value of specific surface of crystal during drying is performed.

Keywords:

• Drying
• Multiphase multicomponent medium
• Shrinkage
• Mutual diffusion
• Crystallisation
• Deposition

Acknowledgments