Experimental and Simulation Study of Cross-Flow Microfiltration Process of Oil-in-Water Emulsion Using Cellulose Acetate Membrane

Hydrocarbon sewage and the related environmental problems have an caused urgent need for speedy consideration. At the same time, water purification for essential uses has been an incentive for researchers to separate sewages by microfiltration processes over the recent years. In this study, separation of oil-in-water emulsion by cellulose acetate membrane in microfiltration processes has been investigated experimentally and numerically. In the laboratory section, the permeate flux for pure water and oil-in-water emulsion has been obtained at the same and at different trans-membrane pressures. In the simulation section, the steady-state permeate flux has been predicted by the law of Darcy in the COMSOLv5.3 environment and compared against experimental data. The comparison results have shown that the permeate flux predicted values for feed containing oil droplets under steady-state conditions has had errors of 15% and 35% at operating pressures of 1 and 2 bar, but the error  for pure water has been equal to 5%. the oil-in-water emulsion may be due to not having considered membrane structure, neglecting pore blocking and concentration polarization layer resistances in the Darcy’s equation. By solving mixture equations, mass transfer and  the law of Darcy in the computational domain simultaneously, the effects of various parameters such as cross-flow velocity and trans-membrane pressure on concentration polarization layer thickness and outlet velocities have been analyzed. Finally, when feed cross-flow velocity has increases from 0.1 to 1.1 m/s, the concentration polarization thickness has decreased by 52%, and when trans-membrane pressure has increased from 1 to 2 bars, the maximum velocity of permeate flow increased by almost 190%.