Demulsification of Heavy Crude Oil Emulsion Driven by Natural Materials

Abstract

AbstractThis study investigated the effectiveness of fly ash (FA) and extracted silica (SC) from sand as natural demulsifiers for breaking stable crude oil emulsions and spiltting oil-water into phases. A series of stable emulsion was formulated and the oil-water ratio was 4:6. Various concentrations of either FA or SC ranging from 0.25 – 1% were added into vials containing the prepared emulsions and demulsification test was conducted inside the oven at 70 °C. Rheology and interfacial tension characterizations were used to illustrate the demulsification mechanism of FA and SC demulsifiers. According to the experimental outcomes, the demulsification from the bottle test showed that water removal increased with the increasing FA concentration. The demulsification efficiency (DE) of 0.25, 0.5, 0.75, and 1% FA was 35.33%, 81.99%, 92.67% and 93.77%, respectively; within 150 minutes of demulsification duration while all the tested SC concentrations (0.25, 0.5, 0.75 and 1%) achived 90.11%, 93.87%, 95.89%, and 95.89%, respectively; under the same demulsification period. The reference sample (blank) only achieved DE of 14.76%. Rheological characterization showed that the incorporation of either FA or SC caused the reduction of emulsion viscosity which indicated the breaking of emulsion and separation of oil and water. The results from the interfacial tension measurments revealed that FA and SC could migrate and adsorb at oil-water interface. The addition of either FA or SC in the oil-water system led to a more drastic reduction in the interfacial tension as compared to the interfacial tension of oil-water system devoided of the FA and SC. The interfacial tensions of oil/water system in the presence of 0.25% and 1% FA were 18.91 mN/m and 14.85 mN/m, respectively, and that of 0.25% and 1% SC were 16.44 mN/m and 14.80 mN/m, respectively, after 200 seconds and that of blank sample was recorded to be 18.1 mN/m in the same duration.