Hydrogen incorporation during coal liquefaction

Skowronski, R.P.; Ratto, J.J.; Goldberg, Ira B.; Heredy, L.A.

doi:10.1016/0016-2361(84)90277-1

Cited by 45 publications

(26 citation statements)

References 15 publications

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“…Many other researchers also suggest that, in the presence of catalyst and pressurized hydrogen, the main hydrogen transfer occurs directly from molecular hydrogen to coal rather than via hydrogen donation solvents, [204][205][206] and that the role of the solvent is to provide good dissolution of coal rather than as a ''hydrogen shuttle''. 207 Tritium and 14 C tracer methods were also used to elucidate the hydrogen transfer mechanism in DCL.…”

Section: Hydrogen Transfer Mechanismsmentioning

confidence: 99%

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Vasireddy

Morreale

Cugini

et al. 2011

Energy Environ. Sci.

344

209

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Increased demand for liquid transportation fuels coupled with gradual depletion of oil reserves and volatile petroleum prices have recently renewed interest in coal-to-liquids (CTL) technologies. Large recoverable global coal reserves can provide liquid fuels and significantly reduce dependence on oil imports. Direct coal liquefaction (DCL) converts solid coal (H/C ratio z 0.8) to liquid fuels (H/C ratio z 2) by adding hydrogen at high temperature and pressures in the presence or absence of catalyst. This review provides a comprehensive literature survey of the coal structure, chemistry and catalysis involved in direct liquefaction of coal. This report also touches briefly on the historical development and current status of DCL technologies. Key issues, challenges involved in DCL process and directions for the future research are also addressed.

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Section: Hydrogen Transfer Mechanismsmentioning

confidence: 99%

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Vasireddy

Morreale

Cugini

et al. 2011

Energy Environ. Sci.

344

209

View full text Add to dashboard Cite

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“…6 coal. These initial results prompted the study that is discussed in Section III, because it is evident that the gas plays an important role in the chemistry with a very high degree of incorporation in the highly aliphatic constituents of the asphaltenes and the oils as noted in previous work by Skowronski and his associates (35).…”

Section: Reaction Pathwaymentioning

confidence: 89%

Fundamental reaction pathways during coprocessing

Stock¹,

Gatsis²

1992

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“…Moreover, after providing hydrogen to the free radicals generated from the coal, a part of the solvent accepts the hydrogen atoms in coal structures again . However, other researchers believe that the main hydrogen transfer route in the liquefaction process is from molecular H 2 to coal directly . The solvent serves only to ensure the solubility of coal and may even hinder the hydrogenation of coal by H 2 because of competitive adsorption on coal .…”

Section: Introductionmentioning

confidence: 99%

Isotope Labeling to Study the Hydrogen Transfer Route during Lignite Modification in a Subcritical D₂O–CO System

et al. 2020

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The hydrogen transfer reaction is one of the key chemical processes of coal conversion. The elucidation of the hydrogen transfer mechanism is essential for rational control of the properties and distribution of products. This paper is focused on the hydrogen transfer mechanism of lignite modification in a subcritical D2O–CO system. Using Soxhlet extraction, isotope ratio mass spectrometry, 1H nuclear magnetic resonance, and pyrolysis–gas chromatography–mass spectrometry (Py-GCMS), the deuterium transfer routes in deuterated products and their representative structures were studied. The existing form of deuterium in deuterated products was also proposed. The results showed that the subcritical D2O–CO system can generate active deuterium, which combines with the free radical fragments resulting from coal pyrolysis to form three kinds of deuterated products: n-hexane solute (NS-D), benzene solute (BS-D), and tetrahydrofuran solute (TS-D). Deuterium in the three solutes migrates in the order TS-D → BS-D → NS-D. It was observed that the active deuterium is not transferred to the β sites of the solutes but rather to their ar, α,2, α, and γ sites. Py-GCMS detection results showed that the solutes mainly consist of six representative structures, that is, monocyclic and polycyclic aromatics, alkenes, alkanes, alcohols, and esters. In the modification process, deuterium is incorporated into the monocyclic aromatic structures in the aliphatic side chains first and then in the aromatic ring. For the polycyclic aromatic structures, the active deuterium enters the side chain first and then the aromatic ring having that side chain. A small amount of active deuterium can be incorporated into the alkene and alkane structures directly. However, it mainly transfers to such structures indirectly through thermal cracking of deuterium-containing macromolecular aromatic structures. Active deuterium reduces oxygen in the oxygen-containing structures to form OD or DHO, yet it cannot easily enter the aliphatic and aromatic structures linked to the oxygen-containing structures. This research provides a new perspective for the study of hydrogen transfer routes and can serve as a reference for discussing the molecular mechanisms involved in various coal conversion processes.

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Hydrogen incorporation during coal liquefaction

Cited by 45 publications

References 15 publications

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Fundamental reaction pathways during coprocessing

Isotope Labeling to Study the Hydrogen Transfer Route during Lignite Modification in a Subcritical D₂O–CO System

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Hydrogen incorporation during coal liquefaction

Cited by 45 publications

References 15 publications

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges

Fundamental reaction pathways during coprocessing

Isotope Labeling to Study the Hydrogen Transfer Route during Lignite Modification in a Subcritical D2O–CO System

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Isotope Labeling to Study the Hydrogen Transfer Route during Lignite Modification in a Subcritical D₂O–CO System