Experimental Research Of Catalytic Combustion Of Gasified Biomass Over Alumina Supported Pd And Ni Catalysts

Biogas is viewed as a promising alternative for fossil fuels and catalytic combustion of gasified biomass attracts intensive research interest. Since gasified biomass mainly consists of CO, CH₄, and H₂,further in-depth understanding of the catalytic reaction characteristics of multi-fuels would be an important issue.Besides, a major problem with biogas is that it alsocontains significant quantities of NH₃ (600–4000 ppm) produced from biogenic nitrogen. This NH₃ is a particular challenge since its combustion in a conventional burner resultsin the formation of significant amounts of environmentally harmful nitrogen oxides (NOx). The key problem of catalytic combustion is how to lucubrate the reaction mechanism and prepare the catalysts own low ignition temperature and reducing pollutants generation.The loaded Ni catalysts and the Ni catalysts that promoted by CeO2 and La, were prepared by sequential incipient wetness impregnation ofγ-Al₂O₃ . ThePdcatalysts, supported onγ-Al₂O₃ and promoted by CeO2, were prepared by impregnation method. This paper focus on the experimental research of catalytic combustion of gasified biomass over alumina supported Pd and Ni catalysts.The physico-chemical properties of these catalysts were characterized by BET and XRD techniques.The results indicated that NiO andγ-Al₂O₃ was the main peaks in the different loaded Ni catalyst. Along with the increase of amount of CeO2, the CeO2 diffraction peak was enhanced. The main peaks are CeO2andγAl₂O₃ diffraction peaks in the loaded Ni catalyst impregnated with CeO2 and La, moreover at 62°appear weak NiO crystalling phase diffraction peak.The results of the Catalytic activity indicated that: all the catalyst reduced the light-off temperature of the biomass. Catalytic ignition order for single fuel is H₂> CO > CH₄. The reson is before catalytic ignition and ignition occurs when both fuel and oxygen can adsorb to the surface, the adsorption/desorption processes of reactant would determine the ignition process. Catalytic ignition for order multi-fuels is CO>H₂> CH₄.The multi-fuel results show complete different behaviors from the single fuel cases because of the competition of the simultaneous multi-fuel and oxygen for active sites on the surface.The activity tests were carried out at fuel-rich conditions at three different lambda (air-to-fuel ratio) values or different gases. The results of the Catalytic activity indicated that: along with the increase of air-fuel ratio,the product NO of the ammonia increased. At fuel lean condition, ammonia can be completely transformed. At fuel rich condition, the Pd catalysts which supported onγ-Al₂O₃ and promoted by CeO2 has the best performance of the Selective Catalytic Oxidation, moreover in CO/H₂ / NH₃ and CO/NH₃ atmosphere, none NOX is generated.