Shear enhanced microfiltration and rejection of crude oil drops through a slotted pore membrane including migration velocities

Shear enhanced microfiltration of crude oil/water emulsion is investigated and the effect of an applied shear rate on the rejection of droplets by the membrane is reported. Applying vibration provides shear rate at the membrane surface leading to shear-induced migration and an inertial lift of drops/particles. Both phenomena tend to move the droplets away from the membrane surface. The shear-induced migration and inertial lift increase with increasing of the shear rate. A mathematical model is presented to account for the presence of both phenomena. The developed model is used for theoretical prediction of 100% cut-off of crude oil droplets by the membrane with, and with-out, vibration applied. A satisfactory agreement of the model predictions with experimental data shows that the model can be successfully used for a theoretical prediction of 100% cut-off of droplets by slotted pore membranes. Rejection of droplets increased with applying shear rate: at 8000 s-1 shear rate and 200 l m-2 hr-1 flux rate 3 to 4 μm radius droplets were almost completely rejected reducing 400 ppm of crude in the feed to 7 ppm in the permeate.