Oil Water Separation by Ultrafiltration

Abstract

ABSTRACT Ultrafiltration with one-inch diameter tubular membranes produced highly-purified water from oil emulsions. For kerosene, No. 6 Fuel oil, Venezuelan crude and lubricating oil at input ratios of 100 ppm to 90 percent, treated water was uniformly free of visible oil and had less than ten ppm oil. Ultrafiltration rate depended on oil type, input ratio and operating conditions. Typically, rates were high (50–150 gal/day-ft-2), but decreased with time due to membrane fouling. Factors which increased emulsion stability or decreased concentration polarization (e.g. high feed circulation rate) minimized fouling. Membrane cleanup was simple and effective, with no loss in long-term membrane capacity in over 3000 continuous test hours, with cleanup each 72 hours. Cost and physical requirements for systems of 10, 100, 1000, and 10,000 gpm were estimated for membranes in tubular and spiral wound configurations. The latter, currently untested, is favored because of lower cost, weight, power, and space requirements. Field trials with actual oily wastes are recommended.