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Title: Molecular dynamics of combustion reactions in supercritical carbon dioxide. Part 4: boxed MD study of formyl radical dissociation and recombination

Abstract

Fossil fuel oxy-combustion is an emergent technology where habitual nitrogen diluent is replaced by high pressure (supercritical) carbon dioxide. The supercritical state of CO2 increases the efficiency of the energy conversion and the absence of nitrogen from the reaction mixture reduces pollution by NOx. However, the effects of a supercritical environment on elementary reactions kinetics are not well understood at present. We used boxed molecular dynamics simulations at the QM/MM theory level to predict the kinetics of dissociation/recombination reaction HCO• + [M] ↔ H• + CO + [M], an important elementary step in many combustion processes. A wide range of temperatures (400–1600 K) and pressures (0.3–1000 atm) were studied. Potentials of mean force were plotted and used to predict activation free energies and rate constants. Based on the data obtained, extended Arrhenius equation parameters were fitted and tabulated. The apparent activation energy for the recombination reaction becomes negative above 30 atm. As the temperature increased, the pressure effect on the rate constant decreased. While at 400 K the pressure increase from 0.3 atm to 300 atm accelerated the dissociation reaction by a factor of 250, at 1600 K the same pressure increase accelerated this reaction by a factor of 100.

Authors:
 [1]; ORCiD logo [2];  [3]
  1. Univ. of Central Florida, Orlando, FL (United States). NanoScience Technology Center; Lobachevsky State Univ. of Nizhny Novgorod (Russia)
  2. Univ. of Central Florida, Orlando, FL (United States). NanoScience Technology Center; Univ. of Central Florida, Orlando, FL (United States). School of Modeling, Simulation, and Training; South Ural State Univ. (Russia); National Research Nuclear Univ. MEPhI, Moscow (Russia)
  3. Univ. of Central Florida, Orlando, FL (United States). Center for Advanced Turbomachinery and Energy Research (CATER), Mechanical and Aerospace Engineering
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory-National Energy Research Scientific Computing Center (NERSC); Univ. of Central Florida, Orlando, FL (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
OSTI Identifier:
1543493
DOE Contract Number:  
FE0025260
Resource Type:
Journal Article
Journal Name:
Journal of Molecular Modeling
Additional Journal Information:
Journal Volume: 25; Journal Issue: 2; Journal ID: ISSN 1610-2940
Publisher:
Springer-Verlag
Country of Publication:
United States
Language:
English
Subject:
Biochemistry & Molecular Biology; Biophysics; Chemistry; Computer Science

Citation Formats

Panteleev, Sergey V., Masunov, Artëm E., and Vasu, Subith S. Molecular dynamics of combustion reactions in supercritical carbon dioxide. Part 4: boxed MD study of formyl radical dissociation and recombination. United States: N. p., 2019. Web. doi:10.1007/s00894-018-3912-4.
Panteleev, Sergey V., Masunov, Artëm E., & Vasu, Subith S. Molecular dynamics of combustion reactions in supercritical carbon dioxide. Part 4: boxed MD study of formyl radical dissociation and recombination. United States. doi:10.1007/s00894-018-3912-4.
Panteleev, Sergey V., Masunov, Artëm E., and Vasu, Subith S. Thu . "Molecular dynamics of combustion reactions in supercritical carbon dioxide. Part 4: boxed MD study of formyl radical dissociation and recombination". United States. doi:10.1007/s00894-018-3912-4.
@article{osti_1543493,
title = {Molecular dynamics of combustion reactions in supercritical carbon dioxide. Part 4: boxed MD study of formyl radical dissociation and recombination},
author = {Panteleev, Sergey V. and Masunov, Artëm E. and Vasu, Subith S.},
abstractNote = {Fossil fuel oxy-combustion is an emergent technology where habitual nitrogen diluent is replaced by high pressure (supercritical) carbon dioxide. The supercritical state of CO2 increases the efficiency of the energy conversion and the absence of nitrogen from the reaction mixture reduces pollution by NOx. However, the effects of a supercritical environment on elementary reactions kinetics are not well understood at present. We used boxed molecular dynamics simulations at the QM/MM theory level to predict the kinetics of dissociation/recombination reaction HCO• + [M] ↔ H• + CO + [M], an important elementary step in many combustion processes. A wide range of temperatures (400–1600 K) and pressures (0.3–1000 atm) were studied. Potentials of mean force were plotted and used to predict activation free energies and rate constants. Based on the data obtained, extended Arrhenius equation parameters were fitted and tabulated. The apparent activation energy for the recombination reaction becomes negative above 30 atm. As the temperature increased, the pressure effect on the rate constant decreased. While at 400 K the pressure increase from 0.3 atm to 300 atm accelerated the dissociation reaction by a factor of 250, at 1600 K the same pressure increase accelerated this reaction by a factor of 100.},
doi = {10.1007/s00894-018-3912-4},
journal = {Journal of Molecular Modeling},
issn = {1610-2940},
number = 2,
volume = 25,
place = {United States},
year = {2019},
month = {1}
}

Works referenced in this record:

Vapor–liquid equilibria of mixtures containing alkanes, carbon dioxide, and nitrogen
journal, July 2001

  • Potoff, Jeffrey J.; Siepmann, J. Ilja
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  • DOI: 10.1002/aic.690470719