Quantitative Vacuum Distillation of Crude Oils to Give Residues Amenable to the Asphaltene Determinator Coupled with Saturates, Aromatics, and Resins Separation Characterization

The automated Asphaltene Determinator coupled with saturates, aromatics, and resins (SAR-AD) Separation is a powerful characterization tool initially de-signed, for the rapid and repeatable analysis of asphalt bitumen and petroleum residua. By virtue of the evaporative light scattering detector (ELSD) and the fact that saturates and a portion of aromatics do not contain chromophores, making them undetectable in the 500 or 700 nm detectors, the complete quantification of petroleum fractions by this method is somewhat restricted to samples that do not contain a significant amount of volatiles. Crude oils can contain more than 70% of volatile material, which is not detected by the ELSD. To overcome the SAR-AD volatile limitation, a quantitative vacuum distillation method was developed to capture the volatiles and produce unaltered residua that does not lose volatiles in the ELSD. To complete the characterization, the volatiles are analyzed for their saturate, aromatic, and reactive olefin contents by proton nuclear magnetic resonance spectroscopy (H-1 NMR). The data from these two methods are combined in the form of a modified colloidal instability index to give a more complete profile of the original whole crude oils.