Model development for shelled corn drying in a plug flow fluidized bed dryer

Abstract

In the present study, a differential model of the plug flow fluidized bed dryer for shelled corn was presented. The model was developed by using the mass balance of moisture content inside a control volume of the bed based on the axial dispersion phenomenon and an appropriate drying rate equation. The differential equation resulted from the model was solved numerically by finite difference method. To validate the model, several experiments for shelled corn drying in a plug flow fluidized bed dryer under steady state conditions were performed at three inlet dry solid mass flow rates (245, 420 and 565 g/min), six drying air temperatures (50, 60, 70, 80, 90 and 100 °C) and two weir heights (0.025 and 0.05 m). The model was capable to predict correctly the moisture content of the grains at any locations along the dryer length. Based on the simulation results, the solid moisture content decreased discontinuously at the solid inlet boundary of the bed and then decreased continuously along the dryer length. The simulation results were also analyzed to investigate the effects of inlet gas temperature, weir height and inlet dry solid mass flow rate on the solid moisture content. The solid moisture content decreased by increasing inlet gas temperature and weir height, whereas it increased by increasing the inlet dry solid mass flow rate.