Numerical Analysis on Separation of Emulsified Waste Oil by Electric Field With a Double-Field Coupling Device

It is a challenge with a single process to efficiently complete demulsification and dewatering of waste oil with high water volume content. With hydro-cyclone as the body structure while embedded with high voltage electrode, it can effectively achieve the demulsification and dewatering of waste oil by coupling high voltage electrical field with whirl centrifuge fields (please double check with this terminology). With double-field coupling numerical model, while combined with the fluid flow control equations and user-defined function, effects of electric field conditions on oil-water mixture velocity distribution in the swirl centrifugal field and separation efficiency were analyzed. Numerical simulation results indicated that effect of high voltage electric field embedded in the hydro-cyclone on the internal flow field of the double-field coupling unit was very minor. The simulation results also suggested there was a slight increase for tangential velocity, which is good for oil water separation in emulsions; however, the axial velocity did not have a significant change. Especially, high voltage electric field can significantly enhance separation efficiency of oil and water, leading to overflow port dewatering ratio and outflow port de-oil ratio improved 12.45% and 22.20%, respectively. Therefore, for waste oil demulsification and dewatering, double-field coupling method is better than single field treatment. © 2019, Editorial Office of Acta Petrolei Sinica(Petroleum Processing Section). All right reserved.