Premixed lean methane/air combustion in a catalytic porous foam burner supported with perovskite LaMn_0.4Co_0.6O₃ catalyst with different support materials and pore densities

Methane combustion in two-zone foam burners supported with LaMn_0.4Co_0.6O₃ catalysts is studied. The combustion stability limits are expanded by heterogeneous catalytic reactions. The upper combustion stability limits of catalytic ZrO₂ burners are 75 and 65 cm/s compared with those in catalytic Al₂O₃ burners of 65 and 60 cm/s as pore density increases from 10 to 20 PPI. The central temperatures and uniformities of catalytic foams are improved compared with inert counterparts. The maximum central temperatures are improved while the pore density increases. The maximum central temperatures of catalytic Al₂O₃ foams are reduced when the flow velocity is higher than 50 cm/s. Hydrocarbon (HC) emissions of catalytic burners (less than 450  ppm) are lower than those of inert burners (560–1130 ppm). The HC emissions of ZrO₂ burners are higher than those of Al₂O₃ burners. The carbon monoxide (CO) emissions of catalytic burners (less than 18  ppm) are lower than those of inert burners (10–34 ppm) when the flow velocity is higher than 20 cm/s. Nitrogen oxides (NOx) are formed by thermal pathways, and the NOx emissions of catalytic burners remain low levels of less than 2  ppm, which are lower than those of inert counterparts (3–6 ppm).