Modelling of particle breakage during drying

An advanced theoretical drying model of single wet particle is proposed. The temperature profile in both crust and wet core regions is described by partial differential equations with appropriate boundary conditions. A Stefan-type vapour diffusion through the crust pores and its convection to the drying ambient has been assumed. The results of model validation for of whole milk droplet drying are presented. The reasons of wet particle possible cracking/rupture are analysed for silica drying. It is concluded that the values of thermal stresses in the crust have decisive importance for the silica particle cracking/rapture during drying. Finally, the results of thermal stresses calculation for silica drying under different conditions are presented. (C) 2007 Elsevier B.V. All rights reserved.