AbstractIn this work, tests of catalytic combustion of CH4 enriched syngas are carried out at high pressure (up to 9bar) over a 20wt%LaMnO3/La-γAl2O3 based monolith. The effect of methane and CO2 addition on the catalyst performances is studied at fixed values of the heating value, H2/CO ratio (1.5) and total flow rate. Results show that ignition is driven by CO combustion, which is the most reactive fuel over LaMnO3 catalyst. Methane substitution and CO2 addition lead to higher ignition pressure and higher quenching pressure thus reducing the operability window: However, by reducing the methane substitution (i.e. increasing the mixture reactivity), the detrimental effect of CO2 decreases.As a conclusion, the perovskyte catalyst can be succ...