NOVEL TECHNIQUES FOR OIL-WATER SEPARATION

In this work two novel methods of separation of oil/water dispersions are proposed. In both methods wetting plays an essential role. It has been found that during the flow of a dispersion through thin microporous hydrophobic membranes with pore size similar to drop size, a spontaneous droplet enlargement takes place. This was manifested by very fast gravitational phase separation after one passage of the dispersion through the membrane. The fraction of separated oil was independent of initial oil concentration and also independent in a broad range from the flow rates. As an alternative to the gravitational separators, the enlarged droplets can be removed using hollow fiber modules. The dispersion is led through the lumen of the hollow fibers, the oil phase permeates through the porous membrane. A simplified mechanism is proposed to explain the influence of residence time and flow rate on the efficiency of the hollow fiber separation.