Behin - Department of Chemical Engineering, Faculty of Eng., Razi University, Kermanshah, IRAN
Aghajari - Department of Chemical Engineering, Faculty of Eng., Razi University, Kermanshah, IRAN
Jahromi - Production unit, Iranian Offshore Oil Company, Kharg Island, IRAN

The effect of temperature, pH, and demusifier's dosage on emulsion instability of Doroud 1, Abuzar, and Forouzan crude oil produced at Kharg Island (Iran) was investigated. Increase in temperature accelerated the solubility of resins and asphaltene present in the crude oil and significantly decreased the interfacial tension between the two phases. Experimental results showed that, optimum temperature for instability of three mentioned emulsions was about 60- 65°C and the emulsions was more stable at lower than 40°C. The emulsion stability decreased with demulsifier dosage, because of decreasing interfacial tension. The optimum pH and dimulsifier dosage (at 60°C) for three emulsions were about 8-10 and 20-25mg/l respectively.

oil-water separation, emulsion stability, demulsifier, interfacial tension, crude oil