Device for Evaluating Coalescence of Oil Emulsion

System variables studied include media wettability, filtration velocity, interfacial tension, coalescer depth, and oil viscosity. It was shown that media preferentially wetted by the dispersed phase were better coalescing materials for separation of the oil-water emulsions. Also, preferentially wetted media exhibit smaller head loss than nonwetted media. Coalescence efficiency decreased with increasing filtration velocity and decreasing interfacial tension. No significant differences in oil removal efficiency were found for the range of viscosities studied. Partial coalescence was obtained when a shallow bed of 0.2 cm was used. Adequate coalescence was shown to be possible with a bed depth of 0.4 cm when polyester felt was used. Higher removal efficiencies could be achieved with deeper coalescence beds. A minimum oil saturation of 10% to 15% was found to be necessary for maximum coalescence within the experimental systems studied. An increase in oil removal efficiency can be anticipated as the fibrous bed becomes saturated with oil.