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

Adams, Jeramie J.; Schabron, John F.; Boysen, Ryan

doi:10.1021/ef502829t

Cited by 21 publications

(29 citation statements)

References 31 publications

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“…Nonpolar materials, including linear, branched, and cyclic saturated hydrocarbons, form saturate fractions . They may contain a minor amount of aromatic ring structures, including aliphatic side chains . Aromatics are polar and comprise one or more aromatic rings .…”

Section: Introductionmentioning

confidence: 99%

“…Aromatics are polar and comprise one or more aromatic rings . They are commonly yellow to light brown and have aliphatic cycles and chains and may comprise a small number of heteroatoms . Carbon and hydrogen, possibly some thiophenic sulfur, and few to no heteroatoms, form aromatics fractions, which can be distinguished from the saturate fraction by including one or more aromatic carbon rings …”

Section: Introductionmentioning

confidence: 99%

“…They have a planar aromatic structure and alkane groups and heteroatoms such as sulfur, nitrogen, and oxygen attached to them . Most of the molecules in asphaltene subfraction have a central peri-condensed polyaromatic structure with brown color, which absorbs visible light . Resins and asphaltenes are similar, but resins have a lower polarity and molecular weight compared to asphaltenes. , Resins are polar fractions that are naturally smaller and have more aliphatic cycles or side chains and fewer heteroatoms compared to asphaltene .…”

Section: Introductionmentioning

confidence: 99%

“…Most of the molecules in asphaltene subfraction have a central peri-condensed polyaromatic structure with brown color, which absorbs visible light . Resins and asphaltenes are similar, but resins have a lower polarity and molecular weight compared to asphaltenes. , Resins are polar fractions that are naturally smaller and have more aliphatic cycles or side chains and fewer heteroatoms compared to asphaltene . Another difference between resins and asphaltenes is that resins dissolve in excess light and heavy n -alkanes (C4 and heavier), but asphaltenes are insoluble in aliphatic solvents and soluble in aromatic solvents. , In terms of physical appearance, saturates, aromatics, resins, and asphaltenes are colorless liquid, yellow or red viscous liquid, brown viscous semisolid, and black brittle powder, respectively …”

Section: Introductionmentioning

confidence: 99%

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Automated High-Performance Liquid Chromatography for SARA Analysis (SARA-HPLC)

et al. 2021

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SARA analysis is widely used to separate crude oil components to saturate, aromatic, resin, and asphaltene fractions. Despite the continuous improvement of the current methods, they are still suffering from insufficiencies in providing fast, accurate, and repeatable results. In this study, an automated SARA high-performance liquid chromatograph (SARA-HPLC) is developed and evaluated to overcome the aforementioned limitations and enhance SARA analysis. The developed system is equipped with three columns packed with different stationary phases, including poly(tetrafluoroethylene) (PTFE), silica, and cyano, connected by automated six-port switching valves that can control the flow path of solvents. The system utilizes propane to sweep the primary carrier phase toward a flat and smooth baseline. A sample of 50 μL (bitumen dissolved in toluene) is passed through the columns where chromatographic separation of maltenes occurs. The asphaltene fraction precipitates on PTFE due to excess pentane, resins are adsorbed by the cyano column, and aromatics are retained on the activated silica column. After sweeping the primary carrier phase (n-pentane) using propane, the fractions are eluted from their columns by applying toluene and consequently sent to an ultraviolet light (UV) detector for analysis. The system can be run unattended and automatically, and each run needs 3 h, including system preparation. The obtained results verify that the developed analytical approach is fast, cost-effective, repeatable, and more precise than current SARA analysis methods.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Automated High-Performance Liquid Chromatography for SARA Analysis (SARA-HPLC)

et al. 2021

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“…The drawbacks of these methodologies are well known (summarised [29,30] ), with commonly identified issues including method inconsistencies, poor precision and repeatability, cross-contamination, and obligatory de-asphalting steps. Whilst recent developments in SARA methodologies do allow separation of whole crudes (utilising PTFE packed columns and heptane solutions to precipitate asphaltenes online) [31][32][33] , in practice few labs are equipped to perform such separations. Although employing SARA methods can quickly provide fractions of saturated hydrocarbons for rapid gas chromatography (GC) analysis, compositional studies into the more complex resin and asphaltene fractions require further fractionations and studies commonly employ ultra-high resolution mass spectrometers (uHRMS; e.g.…”

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confidence: 99%

Class Type Separation of the Polar and Apolar Components of Petroleum

et al. 2017

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Identification of the heteroatom (nitrogen, sulfur, and oxygen)-containing compounds of petroleum is of key importance when considering industrial and environmental issues associated with crude oil production. The more commonly performed methods of crude oil fractionation are often insufficient in the extent to which they separate oils, not allowing defined "molecular" fractions to be obtained. Methods capable of performing a class type separation are uncommon and are often extensive and resource and time intensive. Here we report a method for the separation of crude oils into discrete compound classes. The method utilizes both ion exchange and normal phase chromatography to generate fractions of saturated hydrocarbons, aromatic hydrocarbons, basic compounds, naphthenic acids, and other oxygen-containing species, carbazoles, sulfones, and thiophenes from small crude oil samples (∼0.5 g). Assessment of method selectivity with a suite of model compounds has shown the fractions to be well-defined, with classes of model compounds isolated within discrete fractions. Application of the method to five crude oils of varying API gravity (12.1-38.3°) demonstrates a potential for wide-ranging use. Sample recoveries were high (77-98%) with simple evaporative losses correlating closely with total sample loss. Repeatability was also high, demonstrated by triplicate analyses of model compound mixtures, oils spiked with model compounds and oils alone. Separation selectivity was further demonstrated by application of the scheme to the Alaska North Slope (ANS) crude oil and analysis of fractions by comprehensive two-dimensional gas-chromatography mass-spectrometry (GC × GC/MS) and/or liquid-chromatography high-resolution accurate-mass mass-spectrometry methods (LC-HRAM-MS). Isolation of discrete fractions then allowed excellent separation (by LC and GC methods) of carbazole, dibenzothiophene, fluorenones, xanthones, and quinoline fractions. Individual parent and C alkyl homologues were easily separated (GC × GC/MS), allowing high-quality mass spectra (EI) to be obtained for the individual compounds in many cases. Analysis of fractions by GC × GC/MS also allowed a series of thioxanones to be identified.

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