Separation of water in oil emulsions using microfiltration

The effect of factors influencing the on separation of water in oil emulsions was investigated. A hydrophobic PTFE membrane with 0.45 μm pore size was used. Gas oil, distilled water and Span 80 were selected as continuous phase, dispersed phase and emulsifier, respectively. The prepared emulsions contained 5-20 vol% water and 0.2-0.8 vol% emulsifier. Taguchi experimental design was used to plan a minimum number of experiments. A L16 orthogonal array (Five factors in four levels) was employed to evaluate effect of water and emulsifier content in feed, operating pressure, operating temperature and feed residence time in module on the response (permeate flux and water content in permeate). Preliminary experiments were carried out to identify critical feed conditions. It was shown that increasing emulsifier content and decreasing water content feed decrease permeate flux and water content in permeate. Obviously, minimum and maximum permeate flux was observed when emulsifier and water content in feed were held at their maximum and minimum levels, respectively. It was found that decreasing residence time to its lower limit causes permeate flux to increase. It was also found that, contrary to other microfiltration processes, temperature is an effective factor on the response and increasing pressure decreases permeate flux. Analyzing of variance was finally applied to determine the optimum operating condition as well as contribution of each factor on the response.