Analysis of catalytic combustion in a tubular reactor with methane-air premixtures over the platinum catalyst

The strict regulations lead to an alternative approach in gas turbines with catalytic combustion, which can result in ultra-low emission levels of NO_X, CO and unburned hydrocarbons. The presence of a catalyst inside an engine enables complete combustion of fuel/air mixture at lower temperature which promotes desired chemical reactions. In this work, to find the thermal behavior inside the combustor, the lean premixed fuel/air mixture through an adiabatically catalytic reactive process is analyzed numerically with detailed gas and surface chemistries. The simplified approach with single catalyst channel is adopted to investigate the catalytic combustion behaviors over the Pt catalyst by implementing the concept of Plug flow reactor (PFR). The comprehensive description for catalytic combustion behavior in a single channel is presented by validating the surface reaction mechanisms. The effects of operating parameters such as the temperature, velocity and fuel/air ratios are examined to find the importance of surface reactions. The coupling between gas and surface reactions in the catalyst bed is studied by investigating the commencement of flame ignition with respect to the surface site species. Further, the study shows the only presence of catalytic reactions at the channel entrance, where the gas reactions gets initiated by the rise in flame ignition.