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Abstract: Shear enhanced microfiltration of crude oil/water emulsion is investigated and the effect of an applied shear rate on the rejection of drops by the membrane is reported. Applying vibration provides shear at the membrane surface leading to shear-induced migration and an inertial lift of drops/particles. Both phenomena tend to move the drops away from the membrane surface. The shear-induced migration and inertial lift migration increase with increasing shear rates. A mathematical model is presented to account for the presence of both phenomena. The developed model is used for theoretical prediction of 100% cut-off of crude oil drops by the membrane with, and with-out, vibration applied. A satisfactory agreement of the model predictions with experimental data shows that the model can be successfully used for a theoretical prediction of 100% cut-off of drops by slotted pore membranes. When applying a shear rate of 8000s−1 and 200lm−2 h−1 flux rate, 3–4μm radius drops were almost completely rejected; reducing 400ppm of crude in the feed to 7ppm in the permeate. [Copyright &y& Elsevier]

Abstract: The effect of interfacial tension between two fluids, on the passage and rejection of oil droplets through slotted pore membranes is reported. A mathematical model was developed in order to predict conditions for 100% cut-off of oil droplets through the membrane as a function of permeate flux rate. Good agreement of theoretical predictions with experimental data shows that the model can be applied to the filtration of deformable droplets through slotted pore membranes. At high interfacial tension (40mN/m) with lower flux (200lm−2 hr−1)droplets of crude oil (27 API) were 100% rejected at droplet diameter 4.3μm using a 4μm slotted pore membrane. At lower interfacial tension (5mN/m), with the same flux rate, 100% rejection occurred at 10μm droplet diameter using the same membrane. It was also found that the droplet rejection efficiency below the 100% cut-off was roughly linear with drop size, down to zero rejection at zero drop diameter. Hence, the model, coupled with this approximate correlation, can be used to predict dispersed oil drop concentration from a known feed drop size distribution. [Copyright &y& Elsevier]

Abstract: Oil droplets from an emulsion were filtered using a slotted pore membrane with a 4μm slot width and 400μm slot length. Droplets up to 15μm in diameter were filtered at various flux rates (200–1200lm−2 h−1) using oscillatory membrane microfiltration. Surface shear rates at the membrane of various intensities (0, 1200, 3200 and 8100s−1) were applied and the effect on permeate flux rate and trans-membrane pressure were investigated. Near constant filtration flux was obtained for all the tests. Without shear the trans-membrane pressure increased quickly, but at the highest shear rate (8100s−1) nearly constant trans-membrane pressure and flux rate were observed and may be described as sustainable, or weak form of critical flux. A filtration membrane blocking model was used to investigate the filtration and identify when sustainable, or critical, flux was achieved. [Copyright &y& Elsevier]