Effect of Radial Air Profiles on a Countercurrent Moving Bed Drying

Heat and mass transfer in moving bed dryers is usually modelled based on the application of mass and energy balance equations for both solid and fluid phases (two-phase model). The development of these equations is based on the assumption of classical hypotheses, including flat air velocity profiles. The main goal of this work was to ascertain the validity of this hypothesis by means of an experimental and simulation study of a countercurrent moving bed, using soybean seeds as particles. The radial air profile was taken into account by means of a suitable empirical correlation and a mechanistic model validated by experimental results. Comparisons of the experimental data and the simulated responses indicated that the hypothesis of flat air velocity profiles limits the precision of the results obtained by the model.