CATALYTIC COMBUSTION OF GASIFIED BIOMASS OVER PT AL2O3/

Catalytic combustion of gasified biomass over Pt/Al2O3 was investigate d to clarify its dependence on the fuel gas composition and the air-fu el ratio. An experimental study was performed using synthetic mixtures of the main components in gasified biomass: carbon monoxide, hydrogen , methane, carbon dioxide, water, benzene (model aromatic compound), a mmonia, and inert (argon or nitrogen). Results showed that carbon mono xide and hydrogen ignited simultaneously over the catalyst used, with methane having a higher ignition temperature than that of carbon monox ide and hydrogen. The ignition temperature for carbon monoxide and hyd rogen decreased as the oxygen-fuel ratio and inert concentration incre ased. The presence of water vapor in the feed had an inhibiting effect on the ignition of carbon monoxide, whereas the opposite was observed for methane. Methane ignition was favored by the presence of carbon m onoxide and hydrogen, not only because their combustion heated the cat alyst but also because it attenuated the oxygen inhibition of methane combustion under certain conditions. These effects were explained by c o-adsorption phenomena involving fuel components and oxygen. Ammonia w as found not to influence the combustion of the other components and w as completely converted to nitrogen monoxide over the used catalyst.