Modelling the pneumatic drying of food particles

A one-dimensional model for pneumatic drying of food particles is presented . The model includes mass, momentum and energy transfer between the gas and the solid phases, taking into account variations of properties with humidi ty and temperature as well as solid shrinkage during drying. A plug-flow as sumption is made for the dryer model and the non-spherical shape of particl es is considered in drag and heat transfer coefficients. The set of coupled non-linear ordinary differential equations is solved numerically for the v elocity, moisture and temperature of particles and air along the dryer. The model is applied to simulate the drying of potato particles under differen t conditions. Model predictions are used to illustrate the complex transpor t phenomena that occur during the process and the profiles of temperature, moisture content and pressure developed through the dryer. Effects of mass flowrates ratio, velocity and temperature of air, shape and size of particl e on drying time and final moisture content of the material are studied. (C ) 2001 Elsevier Science Ltd. All rights reserved.