Steam drying a bed of porous spheres: Theory and experiment

The process of steam drying a bed of porous spheres is analysed in terms of a hybrid model that makes use of volume averaged transport equations for the fluid flowing in the bed and point equations for the heat and mass transport taking place in the spheres. To verify the model, a series of experiments with varying mass flux and steam temperature were carried out at atmospheric pressure using ceramic and Al2O3 porous spheres. The comparison between theory and experiment gives good agreement for the total drying rate and the outlet steam temperature for both materials, while the prediction of the internal particle temperatures shows some deviation from the experimental results. (C) 2000 Elsevier Science Ltd. All rights reserved.