Methane pyrolysis is a very attractive and climate-friendly
process
for hydrogen production and the sequestration of carbon as solid material.
The formation of soot particles in methane pyrolysis reactors needs
to be understood for technology scale-up calling for appropriate soot
growth models. A monodisperse model is coupled with a plug flow reactor
model and elementary-step reaction mechanisms to numerically simulate
processes in methane pyrolysis reactors, namely, the chemical conversion
of methane to hydrogen, formation of C–C coupling products
and polycyclic aromatic hydrocarbons, and growth of soot particles.
The soot growth model accounts for the effective structure of the
aggregates by calculating the coagulation frequency from the free-molecular
regime to the continuum regime. It predicts the soot mass, particle
number, area, and volume concentration, along with the particle size
distribution. For comparison, experiments on methane pyrolysis are
carried out at different temperatures and collected soot samples are
characterized using Raman spectroscopy, transmission electron microscopy
(TEM), and dynamic light scattering (DLS).