Energy & Fuels, Vol.26, No.11, 6869-6875, 2012
Asphaltene Precipitation from Crude Oils in the Presence of Emulsified Water
The primary objective of this work was to determine the effect of emulsified water on the onset and the amount of asphaltene precipitation from diluted crude oils. Asphaltene precipitation yields were measured from an Athabasca bitumen and a Gulf of Mexico crude oil diluted with n-heptane. The experiments were performed with and without emulsified water added to the oils. Yields were compared to determine the effect of the emulsified water. At dilution ratios above the onset of precipitation for dewatered oils, yields were observed to be same for both dewatered oils and oils emulsified with water. Hence, the presence of water had no detectable effect on the solubility of asphaltenes in a crude oil. However, asphaltenes adsorbed on the surface of emulsified water droplets were removed with the water droplets and reported as yield below the onset. The secondary objective of this work was to analyze the compositional differences between the asphaltenes precipitated at the onset condition, asphaltenes adsorbed onto the interface, and bulk asphaltenes. On the basis of CHNSO analysis, it was found that there is no compositional difference between these three different asphaltenes.