Mechanical Engineering
NOTICE OF SEMINAR PRESENTATION
CANDIDATE: Syed Muhammad Abdullah Zehravi
DEGREE SOUGHT: MASc
DATE: 2/6/2026
TIME: 10:30am
PLACE: Room 1102 CEI
TITLE: Numerical evaluation of carbon black formation during methane pyrolysis across various chemical mechanisms.
Abstract
Although methane pyrolysis serves as a process that results in CO₂-free hydrogen with a solid carbon by-product, the ability to adequately predict the formation of carbon black precursors and the ultimate carbon black yield by various established chemical kinetic mechanisms remains challenging and widely unexplored. This study critically evaluates five such widely used mechanisms, namely, ABF, KAUST, Caltech, CRECK, and DLR, while utilizing zero-dimensional Constant Volume Reactor (CVR) and one-dimensional Plug Flow Reactor (PFR) models integrated with the Cantera interface, further coupled to a monodisperse population-balance soot model. Findings of the numerical analysis were validated against two distinct shock tube experimental datasets and one flow reactor experimental dataset to assess the performance of the chemical mechanisms. Comprehensive carbon species evolution pathway analyses were further performed at representative temperatures (1800K and 2300K) for the five mechanisms. KAUST and Caltech consistently produced the fastest CH₄ decomposition and, owing to detailed PAH chemistry, yielded the most reliable predictions for PAH species formation, carbon black yield, etc. In contrast, ABF and DLR decomposed methane more slowly, predicted elevated acetylene but under-predicted benzene and carbon black, whereas CRECK showed intermediate trends but was computationally intensive. Pathway analysis further revealed a temperature-dependent effect where, at low temperatures, C₂ species pathways are predominant, limiting PAH growth, whereas at high temperatures, C₃-mediated routes favor benzene and higher PAHs, promoting carbon black inception. These results provide valuable insights into carbon black yield prediction, concerned pathway analyses, and future mechanism developments.