Autothermal reforming of propane for hydrogen production over Pd/CeO2/Al2O3 catalysts

摘要

Steam reforming, partial oxidation and autothermal reforming of hydrocarbons are important routes to hydrogen generation for use in fuel cells. The propane autothermal reforming was studied in supported CeO2/Al2O3 based Pd catalysts, prepared with different Pd precursors. The reaction was carried out under different feedstock conditions and the catalytic activity was evaluated by temperature programmed surface reaction (TPSR). The effects of palladium precursors on the activity and selectivity were studied. Propane autothermal reforming showed three temperature ranges: at relative low temperatures total oxidation occurs; steam reforming occurs at intermediate temperatures when oxygen was completely consumed; and, finally, at higher temperatures the CO2 reforming prevails. The Pd acetylacetonate precursor catalyst was the most active, starting the reforming 100 K less than the Pd chlorine precursor catalyst. The presence of water in the reaction mixture was responsible for an increasing propane conversion and H2/CO ratio when compared without water. Cerium oxide (CeO2) was responsible for the decreasing CO concentration, promoting the water gas shift reaction (CO + H2O ->CO2 + H2). The catalysts were stable with time on stream during 50 h and a small deactivation occurs only at the beginning.