Oil recovery and waste reduction by microwave radiation

Abstract Oil‐in‐water and oil‐water‐solid emulsions, by‐products of various industrial operations, often are environmental concerns. Laboratory and field tests have shown that these emulsions can be demulsified and separated into their individual layers by microwave radiation. The data also show that microwave separation is faster than gravity separation and can be faster than conventnal heating at many conditions. After separation of emulsion into water, slop and oil layers, water can be discharged and oil is collected for recycle. The volume of slop is much smaller than the original volume of emulsion, therefore, the oily waste to be disposed is greatly reduced. The zeta potential of oily droplets in water was measured and found that it is reduced by microwave radiation. This indicates that microwave provides heating and reduction of zeta potential in demulsification.