Modeling of Thin-Layer Drying on an Inert Sphere

A semi-empirical model was developed for the drying of press cake on an inert sphere in the spout region of a dryer. The coefficients for the Lewis and Page (for the prediction of moisture ratio) and the Chung-Pfost (for the prediction of equilibrium moisture content) models were determined experimentally. The predicted temperature of the press cake was validated using three trials conducted at drying conditions (temperature, relative humidity): 55°C, 55%; 65°C, 45%; and 75°C, 43%. Predicted temperatures were within ∼10% of the experimental temperatures. Improved prediction accuracy was achieved as press cake temperature approached air temperature.