Numerical Modeling Catalytic Combustion of Lean H2-CH4 Mixture In a Micro-tube

Catalytic combustion of lean H₂-CH₄ mixtures on Pt at atmospheric pressure was studied numerically, focusing on the impacts of added H₂ and different operational conditions (inlet velocity, wall temperature and surface site density) on the combustion of CH₄. The results show that, the addition of H₂ may lead a decrease of CH₄´s ignition temperature by decreasing the surface coverage of O(s), and the more it is added, the lower the ignition temperature is. The appropriate increases of inlet velocity helps the ignition of CH₄, but a too high velocity may induce incomplete combustion even extinction. The combustion efficiency increases with the increase of wall temperature until the reaction is controlled by mass transport. To meet the need of ignition, surface site density must reach a certain value. Before and after the ignition, surface site density has no influence on the combustion efficiency.