Molecular model and ReaxFF molecular dynamics simulation of coal vitrinite pyrolysis

Li, Wu, Zhu, Yan-ming, Wang, Geoff, Wang, Yang and Liu, Yu (2015) Molecular model and ReaxFF molecular dynamics simulation of coal vitrinite pyrolysis. Journal of Molecular Modeling, 21 8: 1-13. doi:10.1007/s00894-015-2738-6


Author Li, Wu
Zhu, Yan-ming
Wang, Geoff
Wang, Yang
Liu, Yu
Title Molecular model and ReaxFF molecular dynamics simulation of coal vitrinite pyrolysis
Journal name Journal of Molecular Modeling   Check publisher's open access policy
ISSN 1610-2940
0948-5023
Publication date 2015-08
Year available 2015
Sub-type Article (original research)
DOI 10.1007/s00894-015-2738-6
Open Access Status Not Open Access
Volume 21
Issue 8
Start page 1
End page 13
Total pages 13
Place of publication Heidelberg, Germany
Publisher Springer
Collection year 2016
Language eng
Formatted abstract
Vitrinite in coal, the mainly generating methane maceral, plays an important role in hydrocarbon generation of coal. This study aims at obtaining products formation mechanism of vitrinite pyrolysis, and hence determining the chemical bond, molecular liquefaction activity, and reactions mechanism of methane and C2–4 during pyrolysis. The ReaxFF molecular dynamics (MD) simulation was carried out at temperature of 1500 K in order to investigate the mechanism of vitrinite pyrolysis. Initially, a minimum energy conformational structure model was constrained by a combination of elemental and carbon-13 nuclear magnetic resonance (13C NMR) literature data. The model analysis shows the chemical and physical parameters of vitrinite pyrolysis are broadly consistent with the experimental data. Based on the molecular model, ReaxFF MD simulations further provide information of unimolecule such as bond length, and chemical shift, and hence the total population and energy of main products. Molecules bond and pyrolysis fragments, based on active bond analyzed, revealed pyrolysis products of single vitrinite molecule with aliphatic C-C bond, especially ring and chain aliphatic as liquefaction activity. The molecular cell whose density is 0.9 g/cm3 with lowest energy accords with the experimental density 1.33 g/cm3. The content of main products after pyrolysis, classifying as CH4, H2O, and H2, was changed along with the increasing temperature. The gas molecule, fragments and generation pathways of CO2, H2, CH4, and C2H6 were also elucidated. These results show agreement with experimental observations, implying that MD simulation can provide reasonable explanation for the reaction processes involved in coal vitrinite pyrolysis. Thus the mechanism of coal hydrocarbon generation was revealed at the molecular level.
Keyword Coal
Molecular model
Pyrolysis
ReaxFF molecular dynamics
Vitrinite
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2016 Collection
 
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