Hydrogen Evolution from Hydrocarbon Pyrolysis in a Simulated Liquid Metal Bubble Reactor

The evolution of hydrogen from methane decomposition in a liquid metal bubble reactor (LMBR) has become a recent subject of interest; this study examines a novel approach to hydrogen production from pyrolysis of complex hydrocarbon fuels. Modeling hydrocarbon fuel decomposition in an LMBR is executed in two stages of pyrolysis: First, primary pyrolysis intermediates are simulated using a functional-group-based kinetic model (FGMech). Then, a detailed high temperature mechanism (AramcoMech 1.3 + KAUST PAH + 5 solid carbon chemistry) is applied to simulate secondary pyrolysis of intermediates. The quantities of major products of the secondary pyrolysis simulation (CH₄, H₂, C_s, C₆H₆) are approximated by simplified regression equations. Further decomposition of smaller hydrocarbons (until exiting the reactor) is simulated using a coupled kinetic and hydrodynamics model that has been reported in the literature. The mixing effects of bubble coalescence and breakup are investigated in a comparative study on homogeneous and non-homogeneous reactors. Finally, a qualitative relationship between H₂ yield per mass of fuel, functional group, and other factors such as temperature, pressure, and residence time is analyzed. In general, the H/C ratio and cyclic/aromatic content are the main features influencing total conversion to H₂.