Marangoni effect on hydrodynamics and mass transfer behavior in an internal loop airlift reactor under elevated pressure

Abstract

The Marangoni effect on the hydrodynamics and mass transfer was studied in an internal loop airlift reactor with the addition of ethanol under elevated pressure. The overall gas holdup αg increased by ~10% and the gas–liquid volumetric mass‐transfer coefficient kla increased by ~20% on average for each one bar increase in pressure. When the mole fraction of ethanol xE increased from 0 to 0.012, αg increased by ~110% and kla increased by ~50%. However, when xE increased from 0.012 to 0.11, αg decreased by ~40% and kla decreased by ~25%. This volcano‐shaped relationship between both hydrodynamics and mass transfer behavior and ethanol concentration was determined by the Marangoni effect. Semi‐empirical correlations of αg and kla were proposed by including the Marangoni effect in a wide range of ethanol concentration and operating conditions. These correlations gave good predictions of αg and kla compared with extensive experimental data in the literature.