Simulation on performance of a demulsification and dewatering device with coupling double fields: Swirl centrifugal field and high-voltage electric field

Demulsification and dewatering of emulsion oil are common in petroleum and chemical industries. For waste lubricating oil, as a common W/O emulsion, with high water content and complex construction, the multi-field coupling or integration technology can satisfactorily accomplish oil and water separation which cannot be realized by using a single technological method. A coupling device integrated swirl centrifugal and high-voltage electric fields are proposed. Water-droplet coalescence in emulsified oil under the high-voltage electric field can enlarge the droplet size, and the swirl centrifugal field can rapidly and efficiently achieve water-droplet separated from emulsified oil. In this study, the performance of the coupling device was investigated by using numerical simulation and experimental methods. The numerical results were in agreement with the values obtained by experimental methods. And the numerical results show that the dewatering and deoiling rates of overflow and outflow orifices increased by 4.5% and 6.2%, respectively, when voltage amplitude 10 kV increases to 11 kV. Moreover, when inlet velocity increased from 8 m s−1 to 12 m s−1, the separation efficiency gradually decreased. In conclusion, the results demonstrate that the double-field coupling device has a greatly performance at 11 kV and 8 m s−1.