Correlation between Thermal Behavior and Compositions of Fractions from Diverse Canadian Crudes

摘要

While the oil industry has adopted initiatives to use heavy oil and oilsands bitumen as replacements for conventional oil in Canada these heavier oils do not respond well to conventional upgrading processes. The key to improve the processing of such unconventional oils is a better understanding of their molecular chemistry. The approach applied here involves the separation of diversified Canadian crudes, including oilsands bitumen, heavy and conventional oils into asphaltenes and maltenes, followed by further fractionation of the maltene component by high performance liquid chromatography (HPLC). This approach differs from conventional SARA separation in that an aromatic free saturates fraction is produced together with an aromatic fraction plus three resin sub-fractions, all separated on the basis of differences in polarity. This method provides more detailed information on component distribution than other, more established techniques. Of particular interest is that more than 40% of the heteroatoms present in the parent oils accumulated in the resin fractions. The TGA results demonstrate that the saturate and aromatic fractions produce no coke. However, coke formation for the three resin sub- fractions increased dramatically with fraction polarity;the coke forming propensity for these sub- fractions is proportional to their nitrogen content.