Separation of Fine Particles from Nonaqueous Media: Free Energy Analysis and Oil Loss Estimation

Abstract

In industrial processes for the separation of fine particles from oil to produce clean liquid fuels, a significant portion of oil is entrained by the solids and is lost, A semi-empirical model is proposed to explain the mechanism of oil loss and floe carryunder. The favorability of the transfer of fine particles from oil to water was determined by conducting a free energy analysis of the process. The ratio of the water drop to particle radius (size ratio) and the contact angle were found to be important parameters affecting the free energy change. The oil loss was found to increase with an increase in size ratio. To verify the model, experiments to determine oil loss in a practical system were conducted for two different surfactants. The model was found to fit experimental data for oil loss very well. The results show that by choosing a suitable surfactant and demulsifier, it is possible to decrease the oil loss considerably. Hence, the proposed model is useful for evaluating the efficiency of the separation process.