Membrane oscillation and oil drop rejection during produced water purification

• Published in: Separation and purification technology 2015-04, Vol.144, p.16-22
• Main Authors: Ullah, A., Habib, M., Khan, S.W., Ahmad, M.I., Starov, V.M.
• Format: Article
• Language: English
• Subjects: Crude oil; Cut-off; Deforming oil drops; Droplets; Inertial; Lift; Mathematical models; Membrane oscillations; Membranes; Microfiltration; Particle rejection; Produced water; Rejection; Slotted pore membranes
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2015.02.022

•Membrane has been oscillated at various frequencies and its influence on oil rejection has been investigated.•It has found that the generated shear is directly proportional to the oscillation frequency.•A higher rejection of oil drops were noticed as a result of applied shear over the membrane surface. Removal of crude oil droplets from produced water has been evaluated using a Nickel membrane with a slotted pore width of 4μm and length of 400μm. The membrane was oscillated at different frequencies that resulted in variable intensity shears at the membrane surface. The influence of membrane oscillations on oil droplet rejection was investigated and reported in this work. Membrane oscillations generated a lift for the surrounding particles which led the drops to move away from the membrane surface. Measurements have shown that the intensity of the droplet lift was linearly proportional to the intensity of the applied shear. Inertial lift velocity model reported in literature was used as a starting point which was coupled with the fluid’s convection velocity. The model predicted 100% cut-off points through the membrane at various oscillation frequencies. Without the applied shear rate, the static and drag forces balanced each other, which was assumed to be the 100% cut-off point. With the applied shear rate, the inertial lift and convection velocities become equal and this point was referred to as 100% cut-off point. Overall mass of crude oil droplets in permeate flow was calculated knowing the 100% cut-off point and interfacial tension between the dispersed and continuous phases.