Pulsed ultrasound assisted dehydration of waste oil

• We use pulsed ultrasound to help dehydration of waste oil emulsion and achieve a good dehydration.
• We investigate the effect of ultrasonic parameters on the dehydration of waste oil.
• We provide guidance for setting the optimum conditions for the dehydration of waste oil with pulsed ultrasound.

A method to aid the separation of the oil phase from waste oil emulsion of refineries had been developed by using a pulsed ultrasonic irradiation technology. Compared with conventional continuous ultrasonic irradiation, it is found that pulsed ultrasonic irradiation is much better to make water drop coalescence and hence dehydration of waste oil. The effects of ultrasonic irradiation parameters on waste oil dehydration are further discussed. The orthogonal experiment is also designed to investigate the degrees of influence of ultrasonic parameters and the optimal technological conditions. Under the optimal experimental conditions, the water content of waste oil is decreased from 65% to 8%, which thereby satisfies the requirements of refineries on the water content of waste oil after treatment (<10%).