Effect of packing on drop swarms extraction of high viscosity solvents

The terminal velocity and mass transfer coefficients of drop swarms of high viscosity solvents were investigated to study the effect of viscosity on drop behavior in a column packed with super mini ring (SMR) packing. The experimental column was equipped with a multi-channel precise syringe pump and a computerized video imaging system. Cyanex 923S kerosene solutions of different concentrations were used as experimental systems, and their viscosities are ranged from 1.2 to 53.7 mPa S. The effect of drop size and viscosity on the mass transfer coefficient, Kod, has been studied. It is clear from the results that Kod decreases sharply with the increase of viscosity, whereas drop size only has a little effect on Kod. The SMR packing increases Kod significantly up to 100%. Calculations with well-known literature equations cannot predict our experimental data, thus a model considering the interfacial mobility was provided to predict Kod of high viscosity solvents. The model has an adjustable parameter easily obtained from experimental data and fits the experimental data well. A modified Klee-Treybal equation describing terminal velocity under mass transfer conditions was also proposed in this paper.