Determination of hydrocarbon types in petroleum liquids by supercritical fluid chromatography with flame ionization detection

Norris, Thomas A.; Rawdon, Michael G.

doi:10.1021/ac00275a003

Cited by 84 publications

(18 citation statements)

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“…After the first work of Norris et Rawdon [34] showing a satisfactory separation between saturates, olefins and aromatics in gasoline samples using a 20 % silver-loaded silica but lacking reproducibility [35], interesting multidimensional approaches were reported by Campbell et al [35], Fuhr et al [36] and Anderson et al [37,38]. Campbell et al [35] separated saturates, olefins and total aromatics in middle distillates using 10 % mol/mol CO 2 in SF 6 as the mobile phase and two 1-mm-ID columns packed with a silica gel and a silver-loaded strong cation-exchange silica gel.…”

Section: Hydrocarbon Groups By Sfc: Astm Methods 5186-96mentioning

confidence: 99%

Group-type separation and simulated distillation: a niche for SFC

Thiébaut¹,

Robert²

1999

Analusis

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IntroductionApplication of supercritical-fluid chromatography (SFC) for the separation of petroleum compounds really started in the '80s. SFC combines many advantages of gas chromatography (GC) and liquid chromatography (LC): its efficiency is close to GC, it works with GC detectors and involves mobile phases whose solvating power can be tuned as in LC; thus, SFC fills the gap between GC and LC. Petroleum applications are a niche for SFC because it combines GC detectors to LC-like mobile phase: high molecular-weight compounds that could not elute from a GC column elute in SFC, while universal and sensitive GC detection, such as with the flameionization detector (FID), can still be used. As a consequence, typical SFC applications [1][2][3][4] are GC-like separations, e.g. simulated distillation (simdis), and LC-like separations, e.g. hydrocarbon group-separations. However, a GC-like separation does not mean that an open-tubular column must be used. In fact, both packed and capillary columns can be used in SFC, both having their advantages and drawbacks.Simdis is a routine GC application; however, SFC is very attractive for eluting hydrocarbons having more than 80 carbons, which are difficult to elute in GC or high-temperature GC (HTGC) without cracking, because their elution can be obtained on packed or open-tubular columns at much lower temperature compared to HTGC. As SFC can also elute hydrocarbons starting from C 20 to more than C 130 , it is more a competitor than an alternative to GC.The most studied type of LC applications in the petroleum industry is hydrocarbon group-type analysis. SFC's best features for this application are the detection capabilities of FID and the properties of carbon dioxide as a mobile phase. Moreover, FID provides easy quantitation of hydroRecent advances in supercritical-fluid chromatography (SFC) of petroleum fractions are reviewed. Simulated distillation (simdis) still requires some improvements of the hardware so that routine analysis of heavy fractions can be performed. Compared to gas-chromatography simdis, SFC simdis extends the range of this application up to C 140 hydrocarbons, while multi-detection would allow the differentiation of aromatic and non-aromatic hydrocarbons. SFC has been registered by ASTM for hydrocarbon group-type analysis using carbon dioxide. It enables fast separation of aromatic and non-aromatic fractions, subfractionation of aromatics and easier quantitation than in liquid chromatography. Resins and asphaltenes of heavier samples can be backflushed from the column. The method could be further improved for better resolution and quantitation via multiple detection and more selective stationary and mobile phases (CO 2 -SF 6 mixtures for example).Keywords: SFC, simulated distillation, group-type separation, petroleum compounds Article available at http://analusis.edpsciences.org or http://dx.doi.org/10.1051/analusis:1999270681 carbon groups because of the similarity of response factors of most hydrocarbons. Replacing a LC by a SFC method is also worth con...

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Section: Hydrocarbon Groups By Sfc: Astm Methods 5186-96mentioning

confidence: 99%

Group-type separation and simulated distillation: a niche for SFC

Thiébaut¹,

Robert²

1999

Analusis

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“…Moreover, most of these methods are generally prone toward errors: both operational and manual. Some of the above-mentioned methods have also been found to suffer from poor precision and reproducibility besides being time-consuming. , …”

Section: Introductionmentioning

confidence: 99%

“…Some of the above-mentioned methods have also been found to suffer from poor precision and reproducibility besides being time-consuming. 18,19 As per our continuous effort to develop intelligent NMR methods 5−8,20−23 toward petroleum analysis, herein we report a 1 H NMR-based dynamic, accurate, and general method for the estimation of olefin content in all fuel range products ranging from LN/LCN to HN to cracked kero and diesel. This method does not depend on the origin of samples, whether coker or FCC, whether rich in α-, internal, and substituted or cyclic olefins.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Approach for the Estimation of Olefins in Cracked Fuel Range Products of Variable Nature and Composition by ¹H NMR Spectroscopy

et al. 2019

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A dynamic 1H NMR-based method for the estimation of olefin content in all cracked fuel range products, in general, and in gasoline/naphtha streams, in particular, irrespective of types and composition of olefins and boiling range of samples has been developed. This is in continuation of our earlier works where two methods were described for the determination of hydrocarbon types in straight-run gasoline (no olefins) and cracked full range gasoline/naphtha (with olefins). The average absolute number of unsaturated hydrogen (H) in the olefinic region (4.4–6.5 ppm) was directly estimated with the help of a 1H NMR spectrum using dynamic variables in terms of differential population of various kinds of olefins. The average alkyl chain length (n) was estimated by various methods including 13C NMR and carbon number distribution by a gas chromatography-based detailed hydrocarbon analyzer [DHA, ASTM D6730-01(2016)] and simulated distillation [ASTM D2887-16a] data. The percentage of unsaturated hydrogen (% UH) in an average olefin was then obtained providing a multiplication factor (f o) by which the weight percentage of olefin is estimated using a normalized 1H NMR spectrum. The dynamic estimation of H and n for each sample removes the possibilities of errors in the estimation. The method has efficiently been extended to coker kero and coker diesel range products where there has been no method available for olefin estimation. The method was validated by using DHA following ASTM D6730, by the Reformulyzer-based ASTM D6839 method, and finally by fluorescent indicator adsorption following ASTM D1319. All the methods were compared. Whereas the proposed NMR method is extremely general, free from manual error, the limitations of existing ASTM methods and the old NMR method vis á vis a new NMR method are also discussed.

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“…For this reason, several alternatives have been developed over the years. These alternatives include methods based on the complete separation of components by single capillary columns (Sanders and Maynard, 1968;Green and Matt, 1982) or separation according to group types and carbon numbers using multicolumn valve switching approach (Boer and Arkel, 1980; Curvers and Engel, 1988 (Norris and Rawdon, 1984;Schwartz and Brownlee, 1986). Our experience on using different Downloaded by [University of Auckland Library] at 15:58 09 April 2015 hydrocarbon type analyzers has been reported in an earlier study (Kosal et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study of Hydrocarbons Present in Narrow Boiling Range Naphtha Fractions of Saudi Arabian Crude Oils

Ali

1995

Fuel Science and Technology International

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Four Saudi crudes were distilled to produce four narrow boiling range naphtha fractions by true boiling point (TBP) distillation method. These fractions were analyzed for paraffins, olefins, naphthenes and aromatics using a multicolumn valve switching gas chromatographic technique in which hydrocarbons were separated and analyzed according to their types and carbon numbers. It was observed that with increasing average boiling points of the fractions, the paraffins decrease while aromatics have an increasing trend.

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Determination of hydrocarbon types in petroleum liquids by supercritical fluid chromatography with flame ionization detection

Cited by 84 publications

References 7 publications

Group-type separation and simulated distillation: a niche for SFC

Group-type separation and simulated distillation: a niche for SFC

Dynamic Approach for the Estimation of Olefins in Cracked Fuel Range Products of Variable Nature and Composition by ¹H NMR Spectroscopy

A Comparative Study of Hydrocarbons Present in Narrow Boiling Range Naphtha Fractions of Saudi Arabian Crude Oils

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Determination of hydrocarbon types in petroleum liquids by supercritical fluid chromatography with flame ionization detection

Cited by 84 publications

References 7 publications

Group-type separation and simulated distillation: a niche for SFC

Group-type separation and simulated distillation: a niche for SFC

Dynamic Approach for the Estimation of Olefins in Cracked Fuel Range Products of Variable Nature and Composition by 1H NMR Spectroscopy

A Comparative Study of Hydrocarbons Present in Narrow Boiling Range Naphtha Fractions of Saudi Arabian Crude Oils

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Dynamic Approach for the Estimation of Olefins in Cracked Fuel Range Products of Variable Nature and Composition by ¹H NMR Spectroscopy