The application of membrane distillation for the concentration of oil-water emulsions

The influence of the oil presence in the feed on the performance of membran e distillation (MD) has been investigated. The capillary membranes made fro m polypropylene with a maximum pore diameter of 0.62 mu m were used in thes e studies. The concentration of oil in the concentrated feed was in the ran ge of 0-2000 ppm. A decrease of the permeate flux obtained in the process a long with the increase of oil concentration in the feed was observed. In th e case of solutions containing up to 1000 ppm of oil, its presence in the p ermeate was not detected. However, at its higher concentration, the oil per meated into the distillate, for example at c(F) = 2000 ppm, the oil concent ration in the distillate amounted to c(D)=0.6 ppm. The combination of MD wi th a system for oil separation obtained from the emulsion breaking enables maintenance of the oil content in the feed below 1000 ppm.