Catalytic Steam Gasification of Glucose for Hydrogen Production Using Stable Based Ni on a γ–Alumina Fluidizable Catalyst

Abstract

Six different Ni-based fluidizable catalysts were synthesized using both incipient impregnation and co- impregnation. Ni-based catalysts were also promoted with 2.0 wt% La or alternatively with 2 wt% Ce. The preparation procedure included catalysts treated at high temperatures and under free of oxygen conditions. Catalysts were characterized using BET, XRD, AA, PSD, TPR, TPD, H2-chemisorption. TPR and H2 chemisorp-tion showed good metal dispersion with 10 nm- 40 nm metal crystallites. Glucose catalytic gasification runs were performed in a CREC Riser Simulator to evaluate the following cata- lysts: (a) 5 %Ni/γ-Al2O3, (b) 5 %Ni-2 %La/γ-Al2O3 and (c) 5 %Ni-2 %Ce/γ-Al2O3. In all cases, the preparation steps involved acid solutions with pHs of 1 and 4. In between consecutive runs, different approaches were considered: (a) A catalyst was regenerated by air, (b) A catalyst was regenerated by air followed by hydrogen pretreatment, (c) A catalyst was reused directly without any regeneration or hydrogen pretreatment. It was observed that Ni-based catalysts, which were subjected after every run, to both, air regeneration and hydro- gen pretreatment, displayed the best yields in close agreement with thermodynamic equilibrium. On the other hand, Ni-based catalysts regenerated with air only, showed the worst hydrogen yields. In between these two- hydrogen yield limits, where catalysts not contacted with air nor hydrogen, with these yields being moderately below chemical equilibrium. This shows that Ni-based fluidizable catalysts can perform on stream for extended periods, requiring limited reactivation with air and H2. This makes of gasification using the catalysts of the present study, a viable process alternative that could be implemented at industrial scale.