Modelling batch drying of sand in a draft-tube conical spouted bed

A model has been built to predict the evolution of sand drying in a conical spouted bed with a non-porous draft tube. Three regions have been considered in the model, i.e., spout, annulus and fountain, and unsteady-state mass balances have been written for water in the solid and gaseous phases. The model has been validated by comparing its results with the experimental ones obtained in a previous study and it allows predicting the moisture content evolution of both the air and the sand during the drying process.

Research highlights
► A simple model is proposed for predicting drying-time in draft-tube conical spouted beds.
► The model accounts for the additional contact in the fountain that is usually ignored.
► A procedure is proposed for voidage calculation in the spout and fountain zones.
► Gas distribution between spout and annulus is calculated using an anemometer.