Methane Combustion with Cobalt-Substituted Barium-Lanthanum Hexaaluminate Catalysts Supported on Porous Monolithic Honeycombs

Methane combustion with porous honeycomb hexaaluminate catalysts is studied under high temperatures. Cobalt-substituted barium-lanthanum hexaaluminates (Ba1-mLamCoAl11O19±δ) are prepared by co-precipitation procedures and directly deposited onto 300-cpsi porous monolithic honeycomb supports. Catalyst characterizations are performed by scanning electron microscope, X-ray diffraction, and Brunauer-Emmett-Teller method. Effects of La substitution ratio, catalyst content and length, and air preheating temperature on catalytic combustion performances are evaluated. Increasing La substitution ratio can significantly enhance catalyst activity, thermal stability, specific surface area, and combustion performance. The monolithic honeycomb catalyst with largest specific surface area and optimal combustion performance has an optimal catalyst content of 6.0% by weight. The long honeycomb catalyst can improve flame stability limits and reduce pollutant emissions. Increasing air preheating temperature can reduce HC and CO emissions, whereas NOx formation can be improved as the air preheating temperature higher than 250°C.