A Theoretical Study of NH2 Radical Reactions with Propane and Its Kinetic Implications in NH3-Propane Blends’ Oxidation

Binod Raj Giri*, Krishna Prasad Shrestha*, Tam V.T. Mai, Sushant Giri, Mohammad Adil, R. Thirumaleswara Naik, Fabian Mauss, Lam Kim Huynh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The reaction of NH2 radicals with C3H8 is crucial for understanding the combustion behavior of NH3/C3H8 blends. In this study, we investigated the temperature dependence of the rate coefficients for the hydrogen abstraction reactions of C3H8 by NH2 radicals using high-level theoretical approaches. The potential energy surface was constructed at the CCSD(T)/cc-pV(T, Q)//M06-2X/aug-cc-pVTZ level of theory, and the rate coefficients were computed using conventional transition state theory, incorporating the corrections for quantum tunneling and hindered internal rotors (HIR). The computed rate coefficients showed a strong curvature in the Arrhenius behavior, capturing the experimental literature data well at low temperatures. However, at T > 1500 K, the theory severely overpredicted the experimental data. The available theoretical studies did not align with the experiment at high temperatures, and the possible reasons for this discrepancy are discussed. At 300 K, the reaction of NH2 with C3H8 predominantly occurs at the secondary C-H site, which accounts for approximately 95% of the total reaction flux. However, the hydrogen abstraction reaction at the primary C-H site becomes the dominant reaction above 1700 K. A composite kinetic model was built, which incorporated the computed rate coefficients for NH2 + C3H8 reactions. The importance of NH2 + C3H8 reactions in predicting the combustion behavior of NH3/C3H8 blends was demonstrated by kinetic modeling.

Original languageEnglish (US)
Article number5943
JournalEnergies
Volume16
Issue number16
DOIs
StatePublished - Aug 2023

Bibliographical note

Funding Information:
The authors are thankful to the Office of Sponsored Research at King Abdullah University of Science and Technology (KAUST) for funding the research reported in this publication. We are also thankful to Vietnam National University HoChiMinh City (VNU-HCM) under grant number 562-2023-28-01.

Publisher Copyright:
© 2023 by the authors.

Keywords

  • ammonia
  • kinetic modeling
  • kinetics
  • NH
  • propane

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Energy (miscellaneous)
  • Control and Optimization
  • Electrical and Electronic Engineering

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