Application of ultrasonic treatment for demulsification of stable water-in-oil emulsions

In this work, the prospects of using ultrasonic treatment together with a nanosized additive for destruction of stable water-in-oil emulsions of the W/O type of various compositions and properties, with 30–45 μm average diameter droplets, including those containing “gel”, are shown. The influence of such sonication parameters as power and exposure time on the separation efficiency of emulsion in batch mode has been studied. The research was carried out on ultrasonic devices of a submerged and a reactor type. It is shown that destruction above 99% of all the studied emulsions is achieved by using ultrasonic treatment with 1.0 kW power together with the addition of nanopowder AlN suspension in acetone. The exposure time comprised 0.5–3 min, the amount of the additive was equal to 4–8 %vol (depending on the composition and properties of the emulsion). The developed method of demulsification allows to obtain the oil phase with maximum water content of 0.5 wt% and the aqueous phase with maximum oil content of 46 mg L−1. Application of this approach leads to a significant decrease of oily waste formation.