The smaller molecules derived from coal and their significance

Vahrman, M.

doi:10.1016/0016-2361(70)90003-7

Cited by 76 publications

(26 citation statements)

References 6 publications

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“…Although the major routes for vertical migration are believed to be faults and fractures, no rock can remain completely impervious to a widespread flux of hydrocarbons. Extractable molecules resulting from migration into carbonaceous rocks would tend to be adsorbed within the macro-and micro-pores of the kerogen (Vahrman, 1970). In some ways the sediments of the basin resemble a chromatographic column in which the temperature (and hence rates of migration) progressively decrease along the migration path from source to surface.…”

Section: Extract Datamentioning

confidence: 99%

A Reassessment of the Range of Kerogen Maturities in Which Hydrocarbons Are Generated

Saxby

1982

Journal of Petroleum Geology

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The ranges of vitrinite reflectance values, defining zones in which oil andgas generation occur, are examined from severalpoints of view. Geochemical consideration of coalification reactions, kerogen compositions, iso-reflectance lines, spore colour and fluorescence, electron-spin resonance, extract data and reservoir temperatures point to the following approximate ranges: oil generation 1.0-2.0% R,, wet gas and condensate 1.5-3.0% R,, methane2.0-5.0% R,. Biogenicmethanecan beformedat < 0.6 % R, and hydrogen generation from kerogen appears to be possible above 5.0% R,. These results point to hydrocarbon generation under hotter, deeper conditions than thoseproposed in mostprevious schemes. A s a consequence, reflectance ranges are broadened for traces of vitrinite in possible reservoirs: oil < 0.4-1.3% R,, methane < 0.4-3.0% R,.

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Section: Extract Datamentioning

confidence: 99%

A Reassessment of the Range of Kerogen Maturities in Which Hydrocarbons Are Generated

Saxby

1982

Journal of Petroleum Geology

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“…Vahrman 14 found that colloids and molecules with large dimensions emerged early on during low-temperature physical extraction of coal. Prolonged extraction was required to liberate smaller molecules.…”

Section: Energy and Fuelsmentioning

confidence: 99%

Effect of Direct Coal Liquefaction Conditions on Coal Liquid Quality

et al. 2015

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Solvent extraction of coal was investigated with a focus on the quality of the coal liquids rather than coal conversion. The aim was to determine how the hydrogen/carbon ratio and other quality measures were influenced by liquefaction conditions. Liquefaction was performed using Canadian Bienfait lignite in the temperature range of 350−450°C, 4 MPa H 2 , solvent/coal ratio of 2:1, and residence times up to 30 min at liquefaction temperature. An industrial hydrotreated coal liquid was used as the solvent. The hydrogen/carbon ratio of the coal liquids decreased with an increase in coal conversion, so that coal liquid quality decreased with an increase in the maximum liquefaction temperature. Selective extraction of hydrogen-rich material during the initial stages of liquefaction could be explained in terms of the low solubility parameter of the solvent, the weaker association of less polar molecules, and the limited extent of hydrogen transfer between phases. At longer residence times, especially at higher temperature, the coal liquids became heavier (>550°C boiling material) and more aromatic and had a higher density and refractive index. These changes were partly due to increased coal conversion and partly due to increased time for hydrogen transfer, cracking, and recombination reactions to take place. It was further found that the nitrogen content of the coal liquids increased with increasing temperature and residence time. Some industrial implications of the changes in coal liquid quality on process development for coal liquefaction were discussed.

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“…Vahrman et al (30,32,37,42,43) in their several investigations have established that molecules with molecular weights of less than 1000 exist in bituminous coal in quantities larger than so far believed to be present. These molecules have been classified into two categories.…”

Section: Chemical Constitution Of Coalmentioning

confidence: 99%

“…Dev., Vol. 16, No. are extracted with difficulty and the order of extraction is governed by the molecular structure and size (43). The ability of the molecules to penetrate into the micropore structure of coal is well known.…”

Section: Solvent Extraction Of Coalmentioning

confidence: 99%

Liquid Fuels and Chemical Feedstocks from Coal by Supercritical Gas Extraction

Gangoli¹,

Thodos²

1977

Product R&D

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He received his B.Tech (Honors) from Osmania University, India, in 1970, and his M.S. from Northwestern University in 1971. He has co-authored four papers in the water pollution area. His research interests are in environmental sciences, thermodynamics, and synthetic fuels. Mr. Gangoli is a member of the American Institute of Chemical Engineers, Sigma Xi, and Tau Beta Pi; he will be joining the Environmental Control

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The smaller molecules derived from coal and their significance

Cited by 76 publications

References 6 publications

A Reassessment of the Range of Kerogen Maturities in Which Hydrocarbons Are Generated

A Reassessment of the Range of Kerogen Maturities in Which Hydrocarbons Are Generated

Effect of Direct Coal Liquefaction Conditions on Coal Liquid Quality

Liquid Fuels and Chemical Feedstocks from Coal by Supercritical Gas Extraction

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