Influence of Longitudinal Diffusion on the Technological Parameters of a Drum Dryer

In the paper, equations for the operating and equilibrium lines for countercurrent phase flow in a drum dryer have been derived based on differential equations of material balance and mass transfer for the material being dried and the drying agent. A calculation algorithm has been proposed, and the process parameters of the drying process with allowance for longitudinal diffusion have been compared with similar parameters calculated using a standard algorithm. The results in the oblique Ramzin diagram and Euler rectangular coordinates have been plotted. It has been shown that, taking into account the Peclet number of longitudinal diffusion, i.e., the transition from displacement to longitudinal mixing, the calculated drumlength and volume must be increased by a factor of 1.1 or more at Pe < 30.