Transient Analysis of Pasty Material Drying in a Spouted Bed of Inert Particles

The aim of this work is analyzing experimentally the fluid dynamic, thermal, and mass transfer behavior during the transient period of paste drying process in spouted beds. The pasty materials used in this study were water, sewage sludge, skimmed milk, and calcium carbonate. Glass beads of 2.18mm diameter and 2512.70kg/m3 density were used as inert particle. Drying experiments were conducted with spouted beds under two different inlet air velocities, 15 and 30% higher than the minimum spouting velocity, and two ranges of temperature, 80 and 100 degrees C. From these experiments, values of the bed pressure drop, spouting air velocity, particle bed temperature, exhaustion air temperature, and the humidity profile of gas and liquid phases during the transient period were obtained. The results indicate that the analysis of the transient drying period is an adequate and encouraging technique to obtain further information in order to understand the paste drying process in spouted beds.