Experimental and kinetic modeling study of iso-dodecane: Pyrolysis and oxidation

Abstract

2,2,4,6,6-Pentamethylheptane (iso-dodecane) is the primary component of alcohol-to-jet synthetic paraffinic kerosene and also plays a crucial role as an iso-alkane component in jet fuel surrogates. However, there is limited availability of pyrolysis studies on iso-dodecane and its kinetic model requires improvement. In this study, the pyrolysis and oxidation experiments of iso-dodecane were conducted using a flow reactor combined with on-line gas chromatographic (GC) and GC - mass spectrometry (MS) to obtain the mole fraction profiles of species. Based on the obtained experimental data, a new kinetic model for iso-dodecane was developed and validated, demonstrating superior predictive performance compared to the literature models. The rate of production analysis and sensitivity analysis were performed to elucidate the high temperature reaction mechanisms of iso-dodecane. The primary decomposition of iso-dodecane in pyrolysis occurs through unimolecular decomposition channel (U-D) and H-abstraction channel (H-A). The U-D reaction XC₁₂H₂₆ = TC₄H₉ + IC8–5R governs the fuel's reactivity in pyrolysis. Furthermore, a pyrolysis experiment was conducted for n-dodecane under identical conditions to those employed for iso-dodecane pyrolysis, allowing for a comparison between the two fuels based on the experimental data and modeling analysis. Iso-dodecane exhibits higher pyrolysis reactivity than n-dodecane due to its stronger ability in U-D. The new model was also validated by the ignition delay times from the literature.