Numerical modeling of a co-current cascading rotary dryer

A general mathematical model for co-current rotary dryers is presented. A novel approach is taken in modeling of the mass transfer process in the dryer, in which a volumetric mass transfer coefficient, obtained from a general correlation for the volumetric heat transfer coefficient through the Chilton-Colburn analogy, is used. This method does not require the determination of process-specific drying curves, and allows for this model to be easily applicable to a broad range of conditions. The model presented in this work is shown to be able to simulate reliably drying process parameters for a wide range of dryer geometries, input conditions and product types. Dryer data obtained in the present study, as well as data found in the literature, are accurately calculated by the model developed in this work. Simulated moisture content and temperature profiles are in good agreement with data from the literature. A general correlation for the volumetric heat transfer coefficient was determined from the data presented in this study and that from the literature, and was used in this model. The effect of various dryer inlet parameters on the overall performance and energy consumption of the dryer was investigated.