Experimental Study Of Biomass Gasification Catalyzed By CeO₂and ZrO₂Doped Ni Based Catalysts

The influences of CeO₂and ZrO₂doping to Ni based catalysts that catalyzing biomassgasification has been studied. Ce-Ni/Al₂O₃, Zr-Ni/Al₂O₃, Ni/Al₂O₃have been prepared bysol-gel method and applied in biomass catalytic gasification process in thermo gravimetricanalyzer（TGA） and fixed bed with the characterization of BET, X ray diffraction （XRD）and temperature programmed reduction （TPR）.According to the XRD results, it is concluded that both CeO₂and ZrO₂doping arestructure-modified doping. The reactivity of Ni based catalysts that applied in biomasscatalytic gasification in TGA and fixed bed ranking from high to low order is Ce-Ni/Al₂O₃>Zr-Ni/Al₂O₃> Ni/Al₂O₃. Both reactivity and resistance to carbon deposition of Ni basedcatalysts have been improved by CeO₂and ZrO₂doping with the promotion effectsfollowed as the increasing of the quantity of reactive catalytic pairs and the specific surfacearea, the strong electronic interaction between Ni and Ce active sites, and the basicityproperty of ZrO₂. Therefore, the tar yield and char residue decrease both for CeO₂and ZrO₂doped Ni based catalysts, and a general mechanism of biomass gasification catalyzed byCeO₂and ZrO₂doped Ni based catalysts has been proposed respectively.And the Coats-Redfern integration method has been employed to study the kineticmodels of biomass gasification process catalyzed by Ce-Ni/Al₂O₃、Zr-Ni/Al₂O₃andNi/Al₂O₃in TGA. Both CeO₂and ZrO₂doping have decreased the activated energy ofbiomass catalytic gasification process in TGA, activated energy of the pyrolysis stagecatalyzed by Ce-Ni/Al₂O₃, Zr-Ni/Al₂O₃, Ni/Al₂O₃are45.41kJ/mol,47.55kJ/mol,54.45kJ/mol respectively; and activated energy of the gasification stage catalyzed byCe-Ni/Al₂O₃, Zr-Ni/Al₂O₃,Ni/Al₂O₃are88.65kJ/mol,88.83kJ/mol，93.90kJ/molrespectively.