Probing the influence of hydrogen cyanide on PAH chemistry

Peng Liu, Bingjie Chen*, Anthony Bennett, Heinz Pitsch, William L. Roberts

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Hydrogen cyanide (HCN) is an important and highly toxic intermediate in coal, nitrogen-rich biomass, and ammonia combustion. It may play an important role in polycyclic aromatic hydrocarbons (PAH) and soot reduction, but the influence of HCN on PAH chemistry is unclear due to the lack of experimental data. With this motivation, the experimental and numerical investigations were performed in this work. Key intermediates were detected, identified, and quantified by the combination of Linear Trap Quadropole (LTQ) Velos Orbitrap mass spectrometer and gas chromatography-mass spectrometer in a jet-stirred reactor fueled by C2H2/HCN/N2 in the temperature range of 800-1200 K. The results reveal that the formation of benzene increases with the addition of HCN, but the PAH formation decreases. PAH reduction can be attributed to the formation of N-containing PAH (NPAH) via HCN-PAH interaction reactions, which were investigated by quantum chemistry and the Rice–Ramsperger–Kassel–Marcus theory with solving the master equation (RRKM-ME). Reaction rate comparison suggests that the HCN addition pathways to NPAH compete with the C2H2 addition pathways to PAH. The product yields in the systems of 1-naphthyl radical + C2H2 and 1-naphthyl radical + HCN were evaluated (T=800-2500 K and p=0.1-100 atm). The results indicate that the increasement of a new aromatic ring via cyclization is difficult in the 1-naphthyl radical + HCN system due to the high energy barrier, and the growth of larger NPAH is limited since the saturated N atoms in the heterocycle rings and C[tbnd]N functional group inhibit further carbon addition.

Original languageEnglish (US)
Pages (from-to)1139-1146
Number of pages8
JournalProceedings of the Combustion Institute
Volume39
Issue number1
DOIs
StatePublished - Jan 2023

Bibliographical note

Funding Information:
This work was supported by the financial support of CRG project under number URF/1/4688-01-01 by King Abdullah University of Science and Technology (KAUST). BC and HP gratefully acknowledge the funding from the Deutsche Forschungsgemeinschaft within the framework of the collaborative research center SFB/Transregio 129 “Oxyflame”.

Publisher Copyright:
© 2022 The Combustion Institute

Keywords

  • HCN
  • JSR
  • NPAH
  • PAH
  • Reaction pathway

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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