Prediction of Mass Yield, Morphology and Composition of Soot Particles Generated by Pyrolysis of Methane

MOHAMMAD ADIB, Mohammad Reza Kholghy, Carleton University

     Abstract Number: 88
     Working Group: Nanoparticles and Materials Synthesis

Abstract
Soot (black carbon) and Carbon Black are carbonaceous nanoparticles formed during pyrolysis of hydrocarbons. Estimating the mass yield and properties of generated particles is an arduous task due to the complex physics of soot formation. Here, we develop a plug flow reactor code based on a simple Monodisperse Population Balance Model (MPBM) that tracks number concentration, surface area, carbon and hydrogen content of particles to predict mass yield, morphology, and composition (hydrogen/carbon ratio) of particles formed during pyrolysis of ethylene in a flow reactor. The model accounts for the soot inception by the reactive dimerization of polycyclic aromatic hydrocarbons (PAH), and its surface growth by hydrogen abstraction acetylene addition (HACA) as well as the adsorption of PAHs on particle surface. The scaling power-laws from Discrete Element Model (DEM) are used to describe the fractal-like structure of soot agglomerates. The simulations demonstrated the accuracy and robustness of the developed model. The evolution of number concentration, mass, and mobility and primary particles are in good agreement with predictions sectional model population balance model (SPBM). The final mass yield, and mobility diameter were also predicted within 20% of the measurements, but the mobility diameter was underpredicted by 45%. The model can be easily interface with computational fluid dynamic (CFD) to model soot formation in combustion devices and used a process design and optimization tool for synthesis of agglomerate nanoparticles.