Oxygen in Coals and Coal-Derived Liquids

Zhou, P.; Dermer, O. C.; Crynes, B.L.

doi:10.1016/b978-0-12-150703-9.50009-3

Cited by 12 publications

(14 citation statements)

References 147 publications

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“…No solvent was used in the first part of our study, which involved conversion of asphaltenes only and the observations made (Figure and Tables and ). Lastly, it is speculated that tetrahydrofuran could have participated in reactions, such as by hydrogen transfer and/or deoxygenation . In the present work no hydrogen donors were added, except for the experiment conducted with 9,10-dihydroanthracene (Table , exp.…”

Section: Discussionmentioning

confidence: 92%

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Uncatalyzed Hydrogen Transfer during 100–250 °C Conversion of Asphaltenes

2017

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The reactivity and reactions of asphaltenes were explored over the temperature range 100−250°C following reports of reactivity and meaningful free radical content in asphaltenes. This study employed industrial pentane precipitated asphaltenes from Athabasca oilsands bitumen. The presence of free radicals in the asphaltenes feed was confirmed. On heating the asphaltenes to 150°C, the aromatic hydrogen content increased relative to the feed by a factor 1.12. It was also found that on heating the asphaltenes to 150°C the n-heptane insoluble fraction increased from 67% to 75%. Almost no gas phase products were produced. The observed changes were ascribed to hydrogen transfer reactions and addition products formed by combination reactions. Direct evidence of hydrogen transfer reactions taking place in the asphaltenes was obtained through the use of the model systems, α-methylstyrene and cumene, as well as anthracene and 9,10-dihydroanthracene. The extent of hydrogen transfer was of the order 1.8 mg H/g asphaltenes in 1 h at 250°C. Asphaltenes also caused dimerization of model compounds, providing indirect evidence that free radical combination reactions took place in the asphaltenes. Interpretation relying on thermodynamic arguments combined with experimental results indicated that at 250°C the reactive species in asphaltenes were incapable of abstracting hydrogen by hydrogen transfer that had bond strengths (based on homolytic bond dissociation energy) exceeding around 353 kJ mol −1 . Using similar arguments, it was deduced that the ratio of reactive species in asphaltenes capable of abstracting hydrogen with bond strengths in the range around 315−353 kJ mol −1 , compared to transferable hydrogen in asphaltenes with a bond strength less than 315 kJ mol −1 was about 2:1.

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Section: Discussionmentioning

confidence: 92%

“…Lastly, it is speculated that tetrahydrofuran could have participated in reactions, such as by hydrogen transfer and/or deoxygenation. 22 In the present work no hydrogen donors were added, except for the experiment conducted with 9,10-dihydroanthracene (Table 3, exp. G), which is a potential hydrogen donor.…”

Section: Discussionmentioning

confidence: 99%

Uncatalyzed Hydrogen Transfer during 100–250 °C Conversion of Asphaltenes

2017

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“…In coal, there is more diversity of oxygenates. Low-rank coals that are typically used for fuels contain a significant amount of oxygen in the organic matter, much of which occur as phenolic groups, carboxylic acids, and ethers . Oxygenates reduce the heating value of fuels, and it is partly responsible for keeping metals bound to the organic matter, for example, as metal carboxylates. , …”

Section: Processing Challengesmentioning

confidence: 99%

“…Low-rank coals that are typically used for fuels contain a significant amount of oxygen in the organic matter, much of which occur as phenolic groups, carboxylic acids, and ethers. 22 Oxygenates reduce the heating value of fuels, and it is partly responsible for keeping metals bound to the organic matter, for example, as metal carboxylates. 23,24 Reference was made to single functional groups, but in heavy molecules, there may be multiple functional groups and a combination of heteroatoms present in a single molecule.…”

Section: Processing Challengesmentioning

confidence: 99%

Heteroatom Removal as Pretreatment of Boiler Fuels

Siddiquee

Klerk

2019

Energy Fuels

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Heteroatom removal without the use of hydrogen was investigated for the pretreatment of heavy fuels to produce cleaner burning boiler fuels from petroleum residua and coal. This is relevant for applications, such as the production of marine bunker fuel oil, where the anticipated change in maximum sulfur specification in January 2020 is from 3.5 to 0.5 wt %. Processing challenges, such as fluidity, yield loss, and cost-effective reagents, were considered. The study drew primarily on published data; however, claims about key process steps were experimentally verified, and those results are also presented. An oxidative process that employed air as an oxidant was evaluated for oxidative liquefaction and heteroatom removal from coal and petroleum. It was found that this strategy was viable for coal conversion but not for petroleum. Oxidative coal liquefaction produced two potential boiler fuels, an oxidized partly desulfurized coal and a water-soluble coal product. This step was experimentally demonstrated. The experimental work indicated that product separation is potentially challenging. Oxidized sulfur- and nitrogen-rich material must be treated to remove sulfur and nitrogen from the bulk of the hydrocarbon mass, which would otherwise represent a substantial yield loss. This step was not demonstrated. The final processing step involved deoxygenation to improve the heating value of the cleaned boiler fuel. Catalytic deoxygenation over zinc oxide and copper oxide appeared to be promising. Copper oxide supported on a carbon catalyst was evaluated for deoxygenation. Substantial deoxygenation of a mixture of acids was achieved by conversion at 350 °C, with both ketonization and decarboxylation pathways being active for deoxygenation.

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“…Cyclohexane,cyclohexanone, cyclohexanol, 108-93-0. parts. Only recently have they received concerted investigation, and a review of this field has been presented (Zhou et al, 1984).…”

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confidence: 99%

Thermolytic reactions of o-ethylphenol

Zhou¹,

Crynes²

1986

Ind. Eng. Chem. Proc. Des. Dev.

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Asselineau. K.; Busson, C.; Cha, 8.; Sandler, H. wdrocarbon Process. 1968, 47, 131. Alagy, J.; Trambouze, P.; Van Landeghem, H. Ind. Eng. Chem. Process Des. Dev. 1974. 13, 317. Furman, M. S.; Goldmen, A. M., Eds., Pro/svodstvo Ciklohexanona i Adipinovoy Kisbty O&/sleniem Ciklohexana ; Khlmija: Moscow, 1967. Grassmann, P. Chem.-Ing.-Tech. 1959, 31, 148. Heijnen, J. J.; Van't Wet, K. Chem. Eng. J. 1984, 28, 821. Kramers, J.; Westerterp, K. R. Elements of Chemical Reactor Design and Krzysztoforski, A.; SzczypiRski, Z.; Ciborowski, S. Die Chem. Prod. 1977, Leibson, 1.; Hoicomb, E. G.; Cacoso, A. G.; Jacmic, J. J. AIChE J. 1956, 2 , Pohorecki. R.; WroRski, S. Kinetyka l Termodynamika Proces6w In.?yn/er/i Pohorecki, R.; Kasperski, W.; Kruszewski, J.; Zmljewski, K. Warsaw Techni-Poluprodukty dla Sintesa follamMov; Cukerman, A. M., Ed.; Goskhimisdat: Splelman, M. AIChE o-Etttlphenol (OEP) was chosen as a representative of singking phenols In coal.derived liquids, and its thermolytic behavior, either neat or in saiutiOn with dodecane, under moderate temperatures and high pressures of N, or H, ,was studied. Side-chain cleavage Is the most important reaction, giving phenol as the main product and some cresols. Dehydroxyiation produces some arenes, and isomerization is slgniflcan~. Heavier phenols are formed as a result of radicalcoupling reactions. OEP is belived to undergo thermolytic conversion mainly by unimdecular dissociation followed by subsequent radical reactions. Corresponding mechanism and reaction networks are suggested. Mutual influences between OEP and dodecane were observed: OEP thermolysis is promoted by dodecane, while dodecane thermolysis is inhibited by OEP. Molecular hydrogen affects reactions probably by radlcal capping. Pseudo-first-order kinetics apply to OEP thermolysis, and kinetic parameters are reported.For coal-derived liquids, about 40% or more are oxygen compounds: most are phenolic, and the rest are o€ ben-zofuran or dibenzofuran types. Despite the fact that oxygen-containing compounds are much more abundant in coal-derived liquids than nitrogen-and sulfur-containing species, the organic oxygen compounds have received little attention compared to their nitrogen and sulfur counter-* To whom correspondence should be sent.

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Oxygen in Coals and Coal-Derived Liquids

Cited by 12 publications

References 147 publications

Uncatalyzed Hydrogen Transfer during 100–250 °C Conversion of Asphaltenes

Uncatalyzed Hydrogen Transfer during 100–250 °C Conversion of Asphaltenes

Heteroatom Removal as Pretreatment of Boiler Fuels

Thermolytic reactions of o-ethylphenol

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