Investigation of hydrodynamic and mass transfer of mercaptan extraction in pulsed and non-pulsed packed columns

We investigated the hydrodynamic behavior and mass transfer characteristics of a pilot-scale conventional packed bed extraction column of mercaptan removal from liquid propane. The extraction column was filled with pall rings structured packing where mercaptan was extracted from the continuous phase to the dispersed phase, accompanied by a chemical reaction in propane-mercaptan-caustic system. The pulsing was introduced into the column to enhance the mass transfer rate. Hydrodynamic parameters such as hold up, flooding velocity and mean drop size were studied together with the effect of chemical reaction on increasing mass transfer performance. Finally, the mass transfer and axial mixing coefficients were obtained from the optimization of data by ADM. It was found that at the pulsation intensity from 0.003 to 0.007 m/s, the maximum mass transfer and minimum axial mixing occurred and it can be concluded that pulsation improves the efficiency of mass transfer just at low intensities.