Pyrolysis chemistry of n-propylcyclohexane via experimental and modeling approaches

Abstract

Pyrolysis of hydrocarbons has a variety of practical applications in energy utilization and conversion. The pyrolysis study on n-propylcyclohexane (n-PCH) was conducted in a flow reactor by using the synchrotron VUV photoionization mass spectrometry. The temperature in this work ranged from 950 to 1300 K, and the pressures were controlled at 30 and 760 Torr with the initial molar concentration of the fuel kept at 0.5% in gaseous mixture. Quantitative measurements were conducted to obtain the mole fractions for over thirty pyrolytic species. The experimental data were compared with the predictions from the newly developed n-PCH kinetic model and previous models. The present model well predicts the chemistry behavior of the n-PCH pyrolysis, including fuel conversion, production of olefins and diolefins, and growth of aromatic species. The primary decomposition of the fuel and the secondary reaction pathways for the cyclic C9H17 and alkylcyclohexyl radicals with their accompanying reaction rates were discussed. Ethylene, propene and 1,3-butadiene were the highest produced intermediates under the investigated pyrolysis conditions. In addition, the high concentrations of light species and the six-membered structure of n-PCH have large effects on the formation of aromatic species, such as benzene, toluene and ethylbenzene.