Three sets of oil and emulsion samples from refinery desalter operations were separated by a series of steps including the solubility-based Asphaltene Determinator (AD) on-column precipitation and re-dissolution technique developed at WRI.  The steps included centrifugation, gravimetric asphaltene precipitation and sequential filtration with 10 micron and 0.45-micron filters, followed by AD on the various materials.  The amounts and nature of asphaltenes in the original oils, and the solubility subfractions of the asphaltenes that contribute to the stability of the rag layer emulsions were characterized.  Representative sample sets from light (API 40), medium (API 25), and heavy (API 20) crude oils were evaluated.  These included the incoming oils to the desalter units; pudding-like emulsions, and the desalted effluent oils.  For all the pudding-like emulsions, the gravimetric heptane asphaltenes from the whole rag layer pudding emulsions contained significantly more methylene chloride:methanol (98:2 v:v) soluble asphaltene components than the incoming or effluent oils.  The results suggest that the most polar and pericondensed aromatic subfractions of asphaltenes play a significant role in stabilizing oil and water emulsions.

Asphaltene subfraction contributions to emulsion stability

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.