Abstract
Having a better understanding of polycyclic aromatic hydrocarbon (PAH) formation under flame conditions contributes to optimizing the fuel reforming process, where soot poisons the downstream catalyst. In this work, the phenyl + 1,3-Butadiyne reaction is systematically investigated to examine its contribution to naphthalene formation. The reaction potential energy surfaces were calculated using DFT/M06–2X/cc-pvtz and G4 methods. The temperature- and pressure-dependent reaction rate constants were calculated using RRKM theory with solving master equation. The results revealed that 2-naphthyl could be directly formed by phenyl + 1,3-Butadiyne reaction. With H assistance, naphthalene could be formed by the pathway of phenyl + 1,3-Butadiyne → C6H5CHCCCH (+H) → C6H5CHCHCCH (+H) →naphthalene +H. The proposed pathway is kinetically favorable, and featured by relatively low energy barrier. The importance of the proposed pathway reaction was confirmed in a premixed and a diffusion C2H4/O2/Ar flame simulations, where the enhancement of naphthalene by the investigated reactions is notable. The mole fraction of A2 is promoted by a factor of 10% in premix C2H4/O2/Ar flame and 30% in C2H4/O2/Ar counterflow flame, bringing the prediction results closer to the experimental results. The relative contribution of different reaction route to A2 formation is evaluated for HACA, cyclopentadienyl radical-cyclopentadienyl radical, phenyl-vinylacetylene[1], benzyl radical-propargyl radical, indene-CH2 and phenyl-1,3-Butadiyne routes in premixed and diffusion C2H4/O2/Ar flames. This work suggests that the PAH growth by 1,3-Butadiyne addition reaction is an effective pathway for A2 formation, which should be considered in future PAH mechanism.
Original language | English (US) |
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Pages (from-to) | 63-71 |
Number of pages | 9 |
Journal | Proceedings of the Combustion Institute |
Volume | 39 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2023 |
Bibliographical note
Funding Information:The authors acknowledge the financial support by the funding from the KAUST CRG project under project number URF/1/4688–01–01 .
Publisher Copyright:
© 2022
Keywords
- DFT
- Naphthalene
- PAH
- Reaction mechanism
- Soot
ASJC Scopus subject areas
- General Chemical Engineering
- Mechanical Engineering
- Physical and Theoretical Chemistry