Oxygen mass transfer in a high solids loading three-phase internal-loop airlift reactor

Abstract

Determinations of volumetric mass transfer coefficient were conducted in a three-phase internal-loop airlift reactor with an enlarged degassing zone. The effect of parameters such as the airflow rate (riser superficial gas velocities between 0.01 and 0.5 m/s), solids loading (up to 30%, v/v), solids density (1023 and 1048 kg/m3) and the liquid-phase properties on kLa was studied. It was observed that the increase of the airflow rate and the introduction of ethanol enhanced the volumetric mass transfer coefficient in the system. On the contrary, the progressive introduction of solids and a small increase on solids density were responsible for the diminishing of the mass transfer rate. Correlations for the volumetric mass transfer coefficient with the riser superficial gas velocity and solids loading were determined for the two solids density and the two liquid-phases. A good agreement between experimental data and the calculated values was obtained.