Abstract

Centrifugal separation of oil and water from streams that is concentrated with oil such as the ones from the oil spill disasters is investigated in this study. The existing theories are largely for Stokes settling of oil drops. In this study, two layers, one rich in oil and another rich in water are allowed to spin in a centrifuge. The tangential velocity profile is derived from the equations of continuity and motion. The power drawn at the inner rotor is calculated for a set of parameters for the system and an angular speed w RPM (revolutions per minute). Each simulation required the solution of four simultaneous equations and simultaneous unknowns. The power draw was found to be linear with angular rotor speed on a log-log plot. The viscosity of the oil was increased five times to study the effect on the power draw. An expression of the interlayer thickness ratio (a) was obtained by use of a component mass balance on oil streams that flow in and out of the continuous centrifuge.

Key words: Centrifugal separation, polar coordinates, equation of motion, layered flow, matrix inversion, computer simulations, power draw, revolutions per minute (RPM).