The dehydration and demulsification of waste oil by ultrasound

In order to solve the difficulty of waste oil separation, time consuming and high energy consumption, the dehydration and demulsification process of water-in-oil emulsions by ultrasound was studied, including temperature, demulsifier, settling time and ultrasonic irradiation time, sound intensity, and acoustic frequency. Compared with traditional demulsification methods, ultrasonic treatment shows the advantages of energy saving and high efficiency. Optimum conditions for demulsification are obtained at 60°C, ultrasonic irradiation for 5 min when the sound intensity is 0.66 W·cm^-2, settling for 6 h, then good performance can be realized to dehydrate the emulsions in this study that the water content can be reduced to 0.1%.