Hydrogen production by autothermal system over Ce/Zr mixed oxides

Abstract

An autothermal system, which is a combination of the partial oxidation and steam reforming processes operated simultaneously in a single reactor, can be an alternative to the hydrogen production. Heat dissipated from partial oxidation will be provided for steam reforming whereas coke formation can be eliminated in the presence of O2 Since Ce/Zr mixed oxides were found to promote the steam reforming and water-gas shift reaction as well as coke gasification, this makes it possible to exploit such mixed oxides in the autothermal system. In this work, Ce/Zr mixed oxides were prepared by sol gel technique. The effects of Ce:Zr molar ratios, urea concentrations, drying methods and Ni loading were investigated on the catalytic properties of Ce/Zr mixed oxides. The catalysts were characterized using a BET surface area measurement, SEM, XRD and FT-Raman spectra. The catalyst performance was tested via iso-octane oxidation at a constant O2/C ratio of 1. It was found that Ce075Ar025O2 exhibited the highest catalytic activity. The Ce075Ar025O2 dried under supercritical conditions has bigger pore sizes and higher pore volumes than that dried by conventional method. For autothermal system studies, the effects of H2O/C and O2/C ratios on 5%Ni/ Ce075Ar025O2 can be served in which H2/CO ratio increases with increasing H2O/C and O2/C rations.