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The effectiveness of commercial oilsands separation processes relies on the water wettability of the solids. Consequently, the interaction between the mineral and organic matter types present in oilsands is of interest. In this work, we report results related to the adsorption of a pentane insoluble fraction from bitumen on kaolinite and illite, the major clay types present in oilsands. We determined adsorption from toluene solution by illite and kaolinite and use a combination of spectroscopic techniques to probe the organic coated clay surfaces to different depths. The results are compared with similar data for equivalent natural fractions from oilsands.

Nearly 50% of bitumen derived from Athabasca oilsands is pitch. The pentane-insoluble fraction is the major coke producer during thermal cracking. Here, we evaluate the thermal behavior of pentane insolubles from various oil sources by correlating thermogravimetric data with structural parameters. The effect of any entrained mineral solids on the thermal properties results was also investigated. Coke yields depended significantly on aromaticity, H/C atomic ratios, molecular weight, chain length, and equivalent molecular diameter. With the exception of highly aliphatic Daqing conventional oil, coke yields correlated well with the calculated structural parameters. Asphaltene from bitumen was about average in its coke-forming propensity. Mineral solids had practically no effect on thermal behavior.

The boiling point of feedstock is an important process design parameter for petroleum system. In heavy petroleum fractions that boil above 524°C, it is difficult to explicitly determine the boiling point due to limitation of analytical capability. In this article, a modified Cordes-Rarey group contribution method for estimating boiling point of heavy oil was developed on the basis of structure parameters of oil fractions. Narrow fractions of heavy oil were prepared by using the supercritical fluid extraction and fractionation (SFEF). The average boiling points of light SFEF fractions were measured up to 680°C. Elemental analyses and the 1H and 13C-NMR spectra of the SFEF fractions were obtained to determine structure parameters and construct average molecules of SFEF fractions. The results show that the boiling point was correlated with total atom number (except hydrogen) of SFEF fraction. The predicted boiling points for more than 60 SFEF fractions at 320–680°C derived from an Eastern Siberia cr...

As the declining production of conventional light crude oils in North America continues there is increased interest in the heavy oils and bitumen resources of Western Canada. While these oils represent a very large resource, they exhibit unique behavior during upgrading to lighter products. In particular, the heaviest fraction from bitumen pitch (end-cut) is exceptionally intractable. An earlier study showed that the molecular structure of the end-cut comprises three clusters of condensed aromatic and hydroaromatic rings, joined by aliphatic bridges. In this present work we use Computer Aided Molecular Dynamics (CAMD) to provide further insight into the structure of this component. Energy minimization indicates that the most likely bridge length between the clusters comprises five to seven carbon atoms. The calculations also provide information on molecular size and shape, i.e., those properties most closely associated with reactivity in catalytic upgrading processes.

In this work we explore the chemistry of a gas oil fraction in the mid-boiling range (433–483°C) and its products after hydrotreating at 375, 385, and 400°C. Each sample was fractionated by high performance liquid chromatography (HPLC) based on the elution times for saturate, mono-, di-, and poly-aromatic standards. The HPLC saturate fraction is practically free of aromatic components. The nominal mono- and di-aromatics fractions differ in that the former has a higher molecular weight and H/C ratio cbut lower aromaticity and heteroatom content. The H/C atomic ratios, aromaticities, and average structural parameters of the HPLC poly-aromatic subfractions are virtually the same. Regardless of their structural resemblances they differ substantially in their HPLC elution behavior. This can be attributed to the differences in their oxygen and, especially, nitrogen contents. Hydrogenation produced a significantly greater amount of saturate material having a higher H/C ratio than the original feed. A la...

As the Canadian supply of light crudes diminishes, refineries have necessarily been required to deal with more difficult to process oilsands bitumen and heavy oils. Nearly 50% of bitumen consists of a residuum that cannot be easily upgraded. A better understanding of the chemistry of this material is the key to achieving overall optimal yields of commercially useful products. In recent years, the application of supercritical fluid extraction (SCFE) with pentane has been successful in separating the bitumen residuum into a number of narrow fractions based on solubility parameters and molecular weight. In combination with advanced characterization techniques this approach has proved to be useful in elucidating the complexity of bitumen chemistry. To provide further insights into the chemistry of bitumen pitch we now extend this established approach to the solubility classes (saturate, aromatics and resins) derived from the bitumen fractions, or front-cuts, separated during the SCFE process with pen...

X-ray photoelectron spectroscopy (XPS) was used to determine sulphur species and their distribution in fractions of fluid coking residue (CK) and hydro-cracking residue (HC) derived from an Athabasca bitumen pitch (ABP). The major sulphur species were sulphides/mercaptans and thiophenes in each case. No sulphoxides and sulphones were detected in any non-oxidised samples. Each residua was separated into between 9 and 15 front-cut samples and a single end-cut fraction by supercritical fluid extraction and fractionation (SFEF). This approach has been used to produce different molecular weight fractions, depending on the severity of separation conditions. In the fractions from the parent Athabasca bitumen pitch about 65–80 wt% of the total sulphur occurs as thiophenes with the remainder being sulphide species. The reactivity of the sulphur species in the parent pitch was determined under mild conditions using a standard technique for selective oxidation. In this procedure sulphides are preferentially...

Athabasca bitumen is a heavy hydrocarbon recovered from oil sands. During upgrading, bitumen is first distilled to remove lighter components which are processed in hydrotreaters. This distillable portion, heavy gas oil, accumulates nearly 80 w/w% of the saturates present in the original material. The aromatic character and heteroatoms content of the molecules in this fraction increase with the boiling point of the components. The residue from distillation, bitumen pitch, is subjected to thermal cracking followed by hydrotreating. The extractable front fractions from pitch show a trend for increasing aromatic content with a concomitant decrease in H/C atomic ratios. This is a reflection of greater numbers of aromatic rings with a higher degree of condensation and decreasing degree of substitution. The insoluble end- cut from pitch is characterised by the presence of “core” structures comprising condensed polyaromatic rings associated with heteroatoms (N) and trace metals (Ni, V). The heaviest sub-...