An experimental and kinetic modeling study of cyclohexane pyrolysis at low pressure

Zhandong Wang, Zhanjun Cheng, Wenhao Yuan, Jianghuai Cai, Lidong Zhang, Feng Zhang, Fei Qi*, Jing Wang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

Abstract

The pyrolysis of cyclohexane at low pressure (40mbar) was studied in a plug flow reactor from 950 to 1520K by synchrotron VUV photoionization mass spectrometry. More than 30 species were identified by measurement of photoionization efficiency (PIE) spectra, including some radicals like methyl, propargyl, allyl and cyclopentadienyl radicals, and stable products (e.g., 1-hexene, benzene and some aromatics). Among all the products, 1-hexene is formed at the lowest temperature, indicating that the isomerization of cyclohexane to 1-hexene is the dominant initial decomposition channel under the condition of our experiment. We built a kinetic model including 148 species and 557 reactions to simulate the experimental results. The model satisfactorily reproduced the mole fraction profiles of most pyrolysis products. The rate of production (ROP) analysis at 1360 and 1520K shows that cyclohexane is consumed mainly through two reaction sequences: cyclohexane→1-hexene→allyl radical+n-propyl radical, and cyclohexane→cyclohexyl radical→hex-5-en-1-yl radical that further decomposes to 1,3-butadiene via hex-1-en-3-yl and but-3-en-1-yl radicals. Besides the stepwise dehydrogenation of cyclohexane, C3+C3 channels, i.e. C 3H 3+C 3H 3 and C 3H 3+aC 3H 5 also have important contribution to benzene formation. The simulation reveals that C 3H 3+C 3H 3=phenyl+H reaction is the key step for other aromatics formation, i.e. toluene, phenylacetylene, styrene, ethylbenzene and indene in this work.

Original languageEnglish (US)
Pages (from-to)2243-2253
Number of pages11
JournalCombustion and Flame
Volume159
Issue number7
DOIs
StatePublished - Jul 1 2012

Keywords

  • 1-Hexene
  • Benzene formation
  • Cyclohexane pyrolysis
  • Kinetic modeling
  • Synchrotron VUV photoionization mass spectrometry

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

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