Synthesis Gas Production by Catalytic Partial Oxidation of Propane on Mesoporous Nanocrystalline Ni/Al^sub 2^O^sub 3^ Catalysts

Propane partial oxidation to synthesis gas at various feed conditions was investigated over nickel catalysts supported on high surface area γ-alumina. The physicochemical characteristics of the calcined, reduced and spent samples were determined by TPR, BET, XRD, TPO and SEM analyses. The influences of Ni content, reduction and reaction temperatures, gas hourly space velocity (GHSV) and feed ratio on the catalytic properties were investigated. The activity measurements revealed that the propane conversion had a direct relation with reaction temperature and nickel loading and increased with increasing of both these factors. However, there was an optimum value for nickel content and reaction temperature in which the H2 and CO yields were maximum. The 7.5 wt% Ni/Al2O3 exhibited high stability for 12 h without any decrease in activity. However, the selectivity declined gradually with reaction time due to carbon formation. The TPO analysis revealed that an increase in O2/C molar ratio from 0.25 to 0.75 caused a decrease in the amount of deposited carbon. Also, the amount of accumulated carbon slightly decreased with rising the reaction temperature. These results were confirmed by the SEM analysis and the filamentous carbon was observed on the catalyst surface. In addition, the increase in reduction temperature caused an increase in C3H8 conversion and H2/CO ratio.