Synergistic effect on soot formation in counterflow diffusion flames of ethylene-propane mixtures with benzene addition

S. M. Lee, S. S. Yoon, S. H. Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

92 Scopus citations


The characteristics of the formation of polycyclic aromatic hydrocarbon (PAH) and soot in counterflow diffusion flames of ethylene/propane mixtures have been investigated experimentally to identify the effect of fuel structure. The synergistic effect, that is, the enhancement of PAH and soot formation by the fuel mixing of ethylene and propane has been further analyzed to examine the suggested mechanisms based on the competition between PAH and soot growths through the H-abstraction-C2H2-addition (HACA) mechanism and the incipient ring formation through the propargyl recombination reaction. To mitigate the effect of incipient ring formation on the synergistic effect, a small amount of benzene was added to the fuel stream. Planar laser-induced incandescence and laser-induced fluorescence techniques were employed to measure relative soot volume fractions and PAH concentrations, respectively. Results showed that the synergistic effect on soot formation remained, even though the synergistic effects for relatively small aromatics mitigated with the benzene addition. Larger size PAHs have shown enhanced synergistic effects compared to smaller size PAHs regardless of benzene addition. These results implied that the role of propane mixing on the synergistic effect cannot be explained solely by the incipient ring formation via a propargyl recombination reaction; thus, it is suggested that the C3 pathways could also contribute to the growth of PAH species.

Original languageEnglish (US)
Pages (from-to)493-500
Number of pages8
JournalCombustion and Flame
Issue number4
StatePublished - Mar 2004
Externally publishedYes


  • Counterflow diffusion flame
  • PAH growth
  • Soot
  • Synergistic effect

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology
  • General Physics and Astronomy


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