RESIDENCE TIME DISTRIBUTION OF SOLIDS IN A CIRCULATING FLUIDIZED-BED - EXPERIMENTAL AND MODELING STUDIES

A mathematical model, based on the core-annulus flow structure, is proposed to characterize the two-phase flow and the residence time distribution of solids within the riser of circulating fluidized beds. The model is tested against experimental data obtained in a laboratory unit utilizing a tracer technique. While the accuracy of the experimental technique is shown not to be sufficient to allow conclusive results, the model is capable of a good prediction of the observed trends of the characteristic bimodal residence time distributions with an excellent match of the times of arrival of the two peaks. Simulation runs have been performed to study the effects of key operating variables on the residence time distribution. © 1990.