Hydrodynamics and mass transfer of oil-water micro-emulsion in a three phase internal airlift reactor

► A micro-emulsion with the lowest density, viscosity and surface tension had maximum mass transfer and gas hold-up. ► The gas hold-up and mass transfer decreased and liquid circulation velocity increased by solid particles addition. ► Solid loading enhancement had a dramatic effect on the mentioned parameters. ► A proper correlation based on dimensionless numbers was used to predict mass transfer in this process.