Liquid–liquid mass transfer property of two inline high shear mixers

• Liquid–liquid mass transfer were investigated first time in inline high shear mixers.
• Partition coefficient of the benzoic acid between water and kerosene was determined by a linear relationship.
• Mass transfer characteristics under different operation conditions were investigated.
• Dimensionless Sherwood number was correlated with the experimental data.
• Inline HSMs have superior liquid–liquid mass transfer performance and a great application prospect.

The liquid–liquid mass transfer properties of two inline high shear mixers (HSMs) were investigated by the liquid–liquid extraction (LLE) method using the water-benzoic acid-kerosene system. The characteristic parameters of the extraction efficiency (E) and volumetric mass transfer coefficient (KLa) were measured under different conditions involving the rotor speed, two liquid phase flow rates, and surfactant concentration. The results indicate that both E and KLa increase with the rotor speed and aqueous-phase flow rate. The value of E decreases sharply but KLa increases slightly with the organic-phase flow rate. Both E and KLa increase first and then decrease with the surfactant concentrations. Dimensionless correlations for the Sherwood number were obtained to provide guidance on the optimization and scale-up design of these kinds of inline HSMs.