Application of gas/liquid two-phase flow in cross-flow microfiltration of oil-in-water emulsion; permeate flux and fouling mechanism analysis

Abstract

The effects of gas–liquid two-phase flow regimes on permeate flux and fouling mechanisms were investigated in a gas sparging assisted microfiltration of oil-in-water emulsion. Different two-phase flow patterns were attained by introducing gas stream into the liquid phase. It was found that the permeate flux was increased due to disruption of the local deposited cake layer and concentration polarization as the gas velocity increased. Flux enhancement of up to 35% was observed at slug-flow pattern and it was also found that gas sparging is less efficient at high liquid velocities in which turbulence was high. Fouling mechanisms were examined through four individual blocking laws. Membrane resistance curves were used to find dominant fouling mechanism during filtration and as a result, cake formation showed the best agreement with the experimental data in flux decline prediction. The effect of oil droplets on the membrane surface, pore blockage, and accumulation of fouling layer were also analyzed through scanning electron microscopy images.

Keywords:

• Membrane
• Two-phase flow
• Oil-in-water emulsion
• Fouling mechanism

Acknowledgments

The Authors are gratefully thankful to Pars Oil and Gas Company (POGC) for their financial support (contract No. PT/91-177).