Date of Award

5-28-2025

Publication Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Carbon Black; Flow Reactor; Methane Pyrolysis; Pathway Analysis; Shock Tube

Supervisor

Nickolas Eaves

Rights

info:eu-repo/semantics/openAccess

Abstract

In the global pursuit of decarbonization and net-zero emissions, methane pyrolysis offers a promising pathway to produce clean hydrogen energy and carbon black. Carbon black (CB) is the most widely produced nanomaterial by volume, with an annual production of approximately 15 million tons, valued at around $17 billion. However, modeling of such particles is challenging due to the lack of comprehensive chemical mechanisms capable of accurately capturing their precursors under pyrolytic conditions. In this research, the performance of five widely used chemical mechanisms is numerically evaluated against shock tube and flow reactor experimental datasets. A monodisperse population balance model is applied in conjunction with constant volume reactor (0-D) and plug flow reactor (1-D) models inside the Cantera-Python interface to assess species evolution and carbon black properties across a wide range of initial conditions. For 0-D modeling, methane concentrations of 5%, 11.5%, and 25.5% are considered at temperatures ranging from 1400 K to 2500 K, with corresponding pressures of 3 atm, 3.2 atm, and 3.9 atm. In the 1-D flow reactor setup, a 0.5% methane mixture is examined under atmospheric pressure, with ten axial temperature profiles spanning 1073–1673 K. The results indicate that the KAUST and Caltech mechanisms exhibit the fastest methane decomposition rates, while ABF and DLR show the slowest across all operating conditions. The evaluation of carbon black properties reveals that the KAUST and Caltech mechanisms align more closely with experimental data within a specific temperature range compared to the other mechanisms. A comprehensive pathway analysis reveals that at lower temperatures, carbon black formation is predominantly driven by diatomic carbon species, whereas at higher temperatures, tri-carbon species play a key role in forming larger aromatic hydrocarbons. This research will enhance the understanding of carbon black formation pathways and serve as a valuable reference for future mechanism development.

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