Determination of Volatile Hydrocarbons in Coals and Shales Using Supercritical Fluid Extraction and Chromatography

Li, Wenbao; Lazar, Iulia M.; Wan, Yanjian; Butala, Steven J. M.; Shen, Yufeng; Malik, and Abdul; Lee, Milton L.

doi:10.1021/ef960176f

Cited by 13 publications

(16 citation statements)

References 11 publications

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“…Potential advantages of the analytical SFE using CO 2 (SFE-CO 2 ) are faster and more efficient extraction, the absence of thermal degradation, less contamination, and the possibility of on-line coupling with chromatographic methods. SFE-CO 2 has been used for the extraction of hydrocarbons from oils, sedimentary rocks, sediments, soils, coals, and shales (Monin et al, Kesavan et al, Hopfgartner et al., Greibrokk et al, Eckert-Tilotta et al, Erkey et al., Lee et al, Levy et al, Furton et al, Yang et al., Li et al, and Benner). Because it is nonpolar, supercritical carbon dioxide generally exhibits a poorer solvent power than commonly used liquid solvents such as dichloromethane.…”

Section: Introductionmentioning

confidence: 99%

Supercritical Fluid Extraction of Bal 150 Crude Oil Asphaltenes

Guiliano¹,

Boukir²,

Doumenq³

et al. 1999

Energy Fuels

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Supercritical fluid extractions (SFE) from BAL 150 asphaltenes were achieved with carbon dioxide as solvent under various experimental conditions (pressure, temperature, extraction time, and presence of cosolvent). SFE yields were between 5 and 12% of total asphaltenes. Extracts contained mainly linear alkanes (with chain lengths ranging from C14 to C30), various branched alkanes, and a multitude of complex branched and cyclic alkanes as shown by the GC/MS chromatograms. Many aromatic hydrocarbons, heteroaromatic compounds and their methyl derivatives, and polar compounds were also extracted. The best balance between rapid and efficient extraction was obtained for an extraction time of 60 min. Within the range of the study (40−50 °C), the temperature did not show a marked influence upon the extraction efficiency. Pressure and presence of cosolvent appeared to be the major parameters. Increasing pressure (from 130 to 300 bar) yielded to preferential extraction of heavy n-alkanes, more branched and cyclic alkanes, and aromatics. The comparison of extractions performed with or without cosolvent (toluene and dichloromethane) under the same conditions of time and temperature showed that heavier n-alkanes, more highly branched alkanes, and complex cyclic alkanes (biomarkers) were recovered with modifiers.

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Section: Introductionmentioning

confidence: 99%

Supercritical Fluid Extraction of Bal 150 Crude Oil Asphaltenes

Guiliano¹,

Boukir²,

Doumenq³

et al. 1999

Energy Fuels

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“…Coal samples were dynamically extracted with neat supercritical CO 2 (2 h, 120 °C, and 200 atm) using the apparatus shown in Figure and described in detail elsewhere …”

Section: Methodsmentioning

confidence: 99%

Geochemical Significance of n-Alkane Compositional-Trait Variations in Coals

Nelson

Lazar

et al. 1998

Energy Fuels

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The compositional traits of C 9-34 n-alkanes were measured in supercritical CO 2 extracts from 14 U.S. coals of varied geologic ages and wide thermal maturity range (lignite through lowvolatile bituminous). The analysis data exhibit no unique component depletion pattern signatures diagnostic of known types of postgeneration physical, chemical, or microbiological degradation processes that commonly affect crude oil in sedimentary rocks. The C 9-34 n-alkanes in Paleocene and Upper Cretaceous age coals exhibit bimodal carbon-number distribution profiles that strongly resemble those of the biogenic n-alkanoic acids present in brown coals. The compositional trait similarities between these n-alkanes and n-alkanoic acids and the covariance of the bulk coal organic matter atomic oxygen-to-carbon (O/C) ratios and carbon-preference index (CPI) values offer tangible evidence for the existence of a genetic linkage between these two series of compounds. Our analysis results indicate that the C 2-5 alkanes and C 6+ hydrocarbons in coals attain their maximum abundances over the thermal maturity interval from 0.50 to 0.72% R 0 , which, in turn, strongly suggests that these two groups of compounds are formed concurrently by similar overall reaction processes during coal maturation. The compositional traits of the C 4-5 alkanes and C 9-34 n-alkanes in coals appear to uniquely mimic those of the alkane products formed by mineral-catalyzed defunctionalization and cracking of n-alkanoic acids, which suggests that mineral catalysis rather than temperature-controlled thermolysis may be a critical variable controlling the formation and compositional traits of natural gas and C 9+ n-alkanes during coal maturation. These mechanistic insights should be useful to those seeking to formulate improved geochemical models for predicting hydrocarbon evolution during coal maturation.

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“…22−26 Monin et al 14 extracted n-aliphatic hydrocarbons from diverse shale source rocks (of the Mahakam Delta, Indonesia, the Douala Basin, Cameroon, and the Paris Basin, France) in the range of n-C 10 through n-C 34 with supercritical CO 2 (at 40 °C and 20 MPa). Li et al 15 extracted similar ranges of aliphatic and aromatic hydrocarbons from U.S. shales and coals of the Fruitland and Pottsville Formations (Cretaceous and Pennsylvanian periods, respectively) at 120 °C and 20.3 MPa, but focused on quantifying the recovery of more volatile (C 6 to C 14 ) hydrocarbons, with yields ranging between 0.01 and 0.2 wt % (grams of extracted hydrocarbon per gram of sample). However, both studies normalized their yields to the sample mass, with no report of organic richness, type, thermal maturity, or mineralogy.…”

Section: ■ Introductionmentioning

confidence: 99%

Extraction of Hydrocarbons from High-Maturity Marcellus Shale Using Supercritical Carbon Dioxide

et al. 2015

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Shale is now commonly exploited as a hydrocarbon resource. Due to the high degree of geochemical and petrophysical heterogeneity both between shale reservoirs and within a single reservoir, there is a growing need to find more efficient methods of extracting petroleum compounds (crude oil, natural gas, bitumen) from potential source rocks. In this study, supercritical carbon dioxide (CO 2 ) was used to extract n-aliphatic hydrocarbons from ground samples of Marcellus shale. Samples were collected from vertically drilled wells in central and western Pennsylvania, USA, with total organic carbon (TOC) content ranging from 1.5 to 6.2 wt %. Extraction temperature and pressure conditions (80 °C and 21.7 MPa, respectively) were chosen to represent approximate in situ reservoir conditions at sample depth (1920−2280 m). Hydrocarbon yield was evaluated as a function of sample matrix particle size (sieve size) over the following size ranges: 1000−500 μm, 250−125 μm, and 63−25 μm. Several methods of shale characterization including Rock-Eval II pyrolysis, organic petrography, Brunauer−Emmett−Teller surface area, and X-ray diffraction analyses were also performed to better understand potential controls on extraction yields. Despite high sample thermal maturity, results show that supercritical CO 2 can liberate diesel-range (n-C 11 through n-C 21 ) naliphatic hydrocarbons. The total quantity of extracted, resolvable n-aliphatic hydrocarbons ranges from approximately 0.3 to 12 mg of hydrocarbon per gram of TOC. Sieve size does have an effect on extraction yield, with highest recovery from the 250−125 μm size fraction. However, the significance of this effect is limited, likely due to the low size ranges of the extracted shale particles. Additional trends in hydrocarbon yield are observed among all samples, regardless of sieve size: 1) yield increases as a function of specific surface area (r 2 = 0.78); and 2) both yield and surface area increase with increasing TOC content (r 2 = 0.97 and 0.86, respectively). Given that supercritical CO 2 is able to mobilize residual organic matter present in overmature shales, this study contributes to a better understanding of the extent and potential factors affecting the extraction process.

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Determination of Volatile Hydrocarbons in Coals and Shales Using Supercritical Fluid Extraction and Chromatography

Cited by 13 publications

References 11 publications

Supercritical Fluid Extraction of Bal 150 Crude Oil Asphaltenes

Supercritical Fluid Extraction of Bal 150 Crude Oil Asphaltenes

Geochemical Significance of n-Alkane Compositional-Trait Variations in Coals

Extraction of Hydrocarbons from High-Maturity Marcellus Shale Using Supercritical Carbon Dioxide

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