Heavy Petroleum Composition. 1. Exhaustive Compositional Analysis of Athabasca Bitumen HVGO Distillates by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: A Definitive Test of the Boduszynski Model

摘要

Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) allows detailed character-ization of complex petroleum samples at the level of elemental composition assignment. Ultrahigh-resolution (450000-650000 at m/z 500) enables identification of isobaric species that differ in mass by 3 mDa or less, and high mass accuracy (mass error of better than 300 ppb), combined with Kendriclc mass sorting, allows for unambiguous molecular formula assignment to each of more than 10000-20 000 peaks in each mass spectrum. Thus, it is possible to identify, sort, and monitor thousands of elemental compo-sitions simultaneously, as a function of the boiling point. Here, the detailed FT-ICR MS characterization of an Athabasca bitumen heavy vacuum gas oil (HVGO) distillation series exposes the progression of heteroatom class, type (double bond equivalents (DBE), number of rings plus double bonds to carbon), and carbon number for tens of thousands of crude oil species, as a function of the boiling point. Specifically, we analyze a distillation series of Athabasca bitumen HVGO with cut temperatures from the initial boiling point (IBP) to 538 ℃ (in eight cuts) by atmospheric pressure photoionization (APPI), as well as positive and negative electrospray ionization (ESI) FT-ICR MS, to determine the distributions of nonpolar and polar species, as a function of the HVGO boiling point. Compositional distributions reveal definitive heteroatom class, type, and carbon number trends among distillation cuts, and provide the first detailed compositional evidence in support of the Boduszynski model that describes the progression of petroleum composition and structure as a function of the boiling point. Quantitation of the aromaticity and carbon number profiles of both polar and nonpolar species in all distillate cuts further affirms the validity of the Boduszynski model for the HVGO distillate range, and provides evidence for cycloalkane linkages, in addition to polyaromatic cores.