Computer-aided molecular design study of coal model molecules. 3. Density simulation for model structures of bituminous Akabira coal

Dong, Tiaoling; Murata, Satoru; Miura, Masahiro; Nomura, Masakatsu; Nakamura, Kazuo

doi:10.1021/ef00042a061

Cited by 28 publications

(15 citation statements)

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“…The energy minimization technique has been used as an additional tool for constructing coal structure to infer the most favorable spatial arrangement of groups concerned and determine whether the postulated model is consistent with the microporous nature of the coal. We − and a few of other groups ,, have applied this technique on various proposed structural models. However, we have started to realize that previous works which applied this technique have failed to show various structural aspects for coals indicated above, such as the strained nature of the coal.…”

Section: Resultsmentioning

confidence: 99%

Structural Evaluation of Zao Zhuang Coal

et al. 1998

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The structure of Chinese bituminous Zao Zhuang coal was carefully evaluated on the basis of information from NMR, pyrolysis, ruthenium-catalyzed oxidation reaction (RICO), and single coal particle solvent swelling methods. This coal and its SRC liquefaction fractions show good coking property so that the pyrolysis is accompanied by a lot of coke, this being less useful for its structural elucidation than the case of Japanese Akabira coal. The pretreatment of this coal by the ether bond cleavage reaction can increase volatile-comprising molecules that when recognized provide valuable information on molecular constituents of the coal. SPE/MAS 13 C NMR and CP-DD (dipolar dephasing)/MAS 13 C NMR techniques were used to assess carbon distribution. The RICO reaction offered information regarding aliphatic functionalities and bridge types and also suggested the presence of some types of molecular units. Solvent swelling experiments implied that this coal has, on average, relatively low cross-link density and verified the structural heterogeneity of the coal. By using the data from the analytical techniques given above, a model structure of Zao Zhuang coal consisting of one MS, one PS, and two PI structures was constructed. The proposed structure is in keeping with various aspects of its reactivity.

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Section: Resultsmentioning

confidence: 99%

Structural Evaluation of Zao Zhuang Coal

et al. 1998

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“…The densities determined for the coal structures to date are somewhat lower (4-20%) than experimental values. For one of the coals, several structural mod#i(;ations were made in the links between molecular clusters and the effects on density determined (23). In contrast to the studies referenced earlier, cross-linked structures were found to have a significant influence (reduction of ---10%) on density.…”

Section: Viastermentioning

confidence: 78%

95/01128 Applications of molecular modeling in coal research

Carlson¹,

Faulon²

1995

Fuel and Energy Abstracts

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“…Other researchers (Dong et al, 1993;Murta et al, 1993), have used a time step of 100 ps for molecules with a MW of 3000, i.e., similar to that of the endcut sample. The MD run time is dependent on the size of the target molecule.…”

Section: Computation Protocolmentioning

confidence: 99%

Molecular Modeling of the Heavy Components from Athabasca Bitumen Pitch

Gao

Kotlyar

Sparks

et al. 2004

Petroleum Science and Technology

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As the declining production of conventional light crude oils in North America continues there is increased interest in the heavy oils and bitumen resources of Western Canada. While these oils represent a very large resource, they exhibit unique behavior during upgrading to lighter products. In particular, the heaviest fraction from bitumen ORDER REPRINTS pitch (end-cut) is exceptionally intractable. An earlier study showed that the molecular structure of the end-cut comprises three clusters of condensed aromatic and hydroaromatic rings, joined by aliphatic bridges. In this present work we use Computer Aided Molecular Dynamics (CAMD) to provide further insight into the structure of this component. Energy minimization indicates that the most likely bridge length between the clusters comprises five to seven carbon atoms. The calculations also provide information on molecular size and shape, i.e., those properties most closely associated with reactivity in catalytic upgrading processes. 304Gao et al.

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Computer-aided molecular design study of coal model molecules. 3. Density simulation for model structures of bituminous Akabira coal

Cited by 28 publications

References 3 publications

Structural Evaluation of Zao Zhuang Coal

Structural Evaluation of Zao Zhuang Coal

95/01128 Applications of molecular modeling in coal research

Molecular Modeling of the Heavy Components from Athabasca Bitumen Pitch

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