Characterization of high- and non-boiling crude oil fractions. Invited lecture

Abstract

Heavy petroleum fractions such as residues from distillation or heavy crudes will be of growing importance in the future and a characterization scheme was therefore developed for such fractions. In the first step about 50% m/m can be distilled from a typical vacuum distillation residue by short-path molecular distillation. A model for high- and non-boiling petroleum fractions based on the boiling-points, depending on the masses with the double bond equivalent as a parameter, is presented. As short-path molecular distillation works in an extreme non-equilibrium manner, the distillate fractions were characterized by an improved simulated distillation based on gas chromatography. Distillation separates according to the physical parameter, i.e., the boiling-point, regardless of the chemical composition. On extraction with supercritical carbon dioxide a separation method is available that separates according to the structural groups of the molecules. The aromatic fraction in which the hetero components are enriched can be further analysed by high-resolution mass spectrometry using a low-voltage electron impact, avoiding fragmentation. A novel way of presenting high-resolution mass spectra is given. The saturated fraction that is separated by liquid chromatography is analysed by field ionization mass spectrometry. A suitable way of presenting low-resolution mass spectra is given. So far, for all the aforementioned methods, examples are given for one residue only. It would be desirable to check the methods on structurally diverse residues.