A Numerical Study on Turquoise Hydrogen Production by Catalytic Decomposition of Methane

Catalytic decomposition of methane (CDM) is a novel technology for turquoise hydrogen production with solid carbon as the by-product instead of CO2. A computational fluid dynamics model was developed to simulate the CDM process in a 3D fixed bed reactor, accounting for the impact of carbon deposition on catalytic activity. The model was validated with experimental data and demonstrated its capability to predict hydrogen concentration and catalyst deactivation time under varying operating temperatures and methane flow rates. The catalyst lifespan was characterized by the maximum carbon yield (i.e., gC/gcat), which is a crucial indicator for determining the cost of hydrogen generation. Parametric studies were performed to analyse the effect of inlet gas composition and operating pressure on CDM performance. Various CH4/H2 ratios were simulated to improve the methane conversion efficiency, generating a higher amount of hydrogen while increasing the maximum carbon yield up to 49.5 gC/gcat. Additionally, higher operating pressure resulted in higher methane decomposition rates, which reflects the nature of the chemical kinetics.