A pyrolysis study of allylic hydrocarbon fuels

Abstract

The pyrolysis of selected C 3-C 5 allylic hydrocarbons has been studied using a single-pulse shock tube. A new single-pulse shock tube has been designed and constructed by recommissioning an existing conventional shock tube. This facility enables the investigation of high-temperature chemical kinetics with an emphasis on combustion chemistry. The modifications performed on the existing shock tube are described, and the details of the sampling system to analyze the species concentration using a gas chromatography-mass spectrometry-flame ionization detection (GC-MS with a flame ionization detector) system are also provided. This facility is characterized and validated by performing cyclohexene pyrolysis experiments. Furthermore, the performance of the shock tube is demonstrated by reproducing previous literature measurements on the pyrolysis of isobutene. Postvalidation, this setup is used to study the pyrolysis of trans-2butene and 2-methyl-2-butene (2M2B). A newly developed mechanism, NUIG-Mech1.0, is used to simulate the experimental data of propene, isobutene, 2butene, and 2M2B, allylic hydrocarbon fuels. A description using two different kinetic simulation approaches is provided using our isobutene experiments as a reference. We found no significant differences between the two methods. Additionally, the contribution of different reaction classes on fuel consumption is detailed and the influence of geometry on fuel consumption and first aromatic ring: benzene is discussed.

Hierarchical Study of the Reactions of Hydrogen Atoms with Alkenes: A Theoretical Study of the Reactions of Hydrogen Atoms with C2–C4 Alkenes

“…Figure 23 presents species profiles for 2-butene pyrolysis at 2 bar. 35 Again, the pyrolysis chemistry is quite similar to that of propene and 1-butene. Ḣ atom addition to 2-butene forms propene and ĊH 3 radicals through a chemically activated pathway.…”

“…Section 2 describes the computational methods employed in the current work, and Section 3 presents the theoretical results including comparisons with literature studies, where available (Table 1). Section 4.0 presents our simulation results compared to the shock tube pyrolysis experiments of Nagaraja et al 31,33 2. COMPUTATIONAL DETAILS 2.1.…”

Reaction kinetics of 1,4-cyclohexadienes with OH radicals: an experimental and theoretical study

“…Wang et al 10 also highlighted the importance of dehydrogenation reactions of cyclohexadienes accounting for the majority of benzene formation during the pyrolysis of cyclohexene and 1,5-hexadiene. Similarly, Nagaraja et al 13 reported that benzene formation predominantly happens via fulvene in isobutene pyrolysis where the cyclopentadienyl radical plays a critical role; likewise, 4% of the benzene formation occurs via the cyclohexadiene channel in 2-butene pyrolysis. The authors reported that ∼99% of cyclohexadienyl radicals are formed via the fulvene pathway in isobutene and 2-butene pyrolysis.…”

“…This pathway contributes significantly to the formation of benzene during pyrolysis and/or oxidation of cyclic hydrocarbons and/or alkenes under fuel-rich conditions. 2,[9][10][11][12][13] For this pathway, the cyclohexadienyl radical (c-C 6 H 7 ) is an important intermediate species which liberates an H atom to yield benzene (c-C 6 H 6 ). Li et al 11 reported that the chemical pathway via cyclohexadienyl radical contributes almost exclusively to benzene formation in cyclohexane flames under stoichiometric conditions.…”

An experimental and master-equation modeling study of the kinetics of the reaction between resonance-stabilized (CH3)2CCHCH2 radical and molecular oxygen

“…[3][4][5] In addition to soot formation affinity, autoignition chemistry and oxidation kinetics of olefins and olefinic radicals differ significantly from those of similar-size alkanes. 6 Recently olefin flame chemistry 7-9 , pyrolysis 10, 11 , ignition delay times [12][13][14][15] , and oxidation in jet-stirred-reactor (JSR) [16][17][18] experiments have received attention. However, little is still known experimentally on oxidation kinetics of olefinic hydrocarbon radicals larger than allyl 19,20 and methyl-vinyl 21 (i.e.…”