An Improved Model of Plug-Flow Fluidized Bed Dryers with an Emphasis on Energy Conservation

This article describes the development of a plug-flow fluidized bed dryer simulator, which was implemented on Microsoft Excel. The drying kinetics are described by a constant rate period followed by two falling rate periods; both hygroscopic and nonhygroscopic solids were modeled. The flow rate and temperature of the inlet air could be varied along the dryer length and heat losses were taken into account. The simulator was used to generate axial profiles of moisture content, temperature, and specific energy consumption and to perform parametric studies. The results followed logical trends. Building on the results of an earlier study,[1] the present work confirmed that the effect of axial dispersion on the above profiles could be neglected under all conditions. Use of the simulator as a design aid and to explore opportunities for energy conservation was demonstrated.