Hydrogen production from partial oxidation of propane: Effect of SiC addition on Ni/Al2O3 catalyst

One of the most attractive routes for hydrogen production for fuel cell applications is partial oxidation of hydrocarbons. However, exothermic partial oxidation reaction tends to cause local overheating of the reaction bed therefore reducing catalytic activity. In this study, hydrogen production by partial oxidation of propane over Ni/Al2O3 based catalyst with the addition of SiC was experimentally investigated. Both packed bed mixing and bulk doping methods were introduced to study the effect of SiC for its high thermal conductivity and high temperature stability. The as-prepared samples were characterized by a variety of measurements. Due to the high temperature stability of SiC particles in the bulk regions, stacking dual porous-like structures were formed after calcination by doping SiC into Ni/Al2O3 with certain ratios. From the results, local overheating of the catalyst bed generated by the exothermic reactions was relieved by SiC addition for both cases. Ni/Al2O3-SiC (30 wt% SiC) catalyst performed a higher hydrogen production of 236 mu mol/g(cat).s and kept stable for 20 h at 600 degrees C compared to mechanical mixing method. Aggregation of Ni content and carbon deposition of the spent catalyst of SiC-containing catalysts were reduced compared to Ni/Al2O3. As can be seen from the morphological and non-isothermal kinetics, the carbon deposited on Ni/Al2O3-SiC catalyst that caused catalyst deactivation was more easily activated for removal due to SiC content with high thermal conductivity.