Enhanced combustion of lean methane by La-based perovskite catalysts in a porous media burner

Methane emissions from coal mining not only result in significant energy loss but also contribute substantially to the greenhouse effect. This study investigates the application of porous media combustion (PMC) technology for lean methane combustion, with a particular focus on La-based perovskite catalysts. The catalysts (LaFeO3, LaNiO3, and LaMnO3) were synthesized by impregnating them onto alumina spheres using a citric acid complexation impregnation method. Scanning electron microscopy (SEM) analysis revealed that these catalysts significantly enhanced the specific surface area of the porous media, thereby increasing the number of catalytically active sites and reaction interfaces, which in turn improved catalytic activity. Experimental results demonstrated that catalytic combustion improves cold-start response, flame stability, and temperature distribution compared to inert PMC. The catalytic system achieved faster stabilization, attributed to enhanced heat transfer and fuel oxidation. The catalytic burner exhibited a wider range of gas flow rates for flame stabilization (equivalence ratio: 0.325-0.45, gas flow rate: 22.5-75 cm/s) compared to the inert burner (equivalence ratio: 0.35-0.45, gas flow rate: 30-70 cm/s). Notably, the LaMnO3-loaded porous spheres demonstrated superior performance, reaching the highest combustion temperature of 1473 K and a methane conversion efficiency of 92.2 % at an equivalence ratio of 0.45 and a gas flow rate of 75 cm/s. This study highlights the potential of PMC catalyzed by La-based perovskite in treating low-concentration methane emissions, thereby contributing to cleaner combustion processes and environmental sustainability.