Study of nickel catalysts for hydrogen production in sorption enhanced reforming process

Abstract

The performance of Ni based catalysts to be used in Sorption Enhanced Reforming (SER) is assessed. For this aim, both their activity at low temperature and their behavior during multiple oxidation–reduction cycles in steam methane reforming are studied. Ni catalysts supported on α-Al2O3, Si3N4 and NiAl2O4, with different amounts of Ni (0–50% NiO), are compared by testing their activity in a fixed bed micro-reactor. While Ni/Si3N4 catalysts do not show an appropriate performance at low temperature, Ni/α-Al2O3 and Ni/NiAl2O4 present a significant activity, close to equilibrium data, at the typical SER conditions. The best experimental results are attained for 20% NiO/α-Al2O3 and 10% NiO/NiAl2O4 catalysts that show an activity close to the equilibrium for steam to methane ratio of 4.5. Higher amounts of NiO in both catalysts do not reveal an improvement in conversion results. In addition, both 20% NiO/α-Al2O3 and 10% NiO/NiAl2O4 catalysts show a good reforming activity after oxidation–reduction cycles at typical SER temperatures. The observed trend to carbon deposition on the catalyst surface for the studied supports is Si3N4 > Al2O3 > NiAl2O4, being negligible when NiAl2O4 support is used. These results suggested that 10% NiO/NiAl2O4 and 20% NiO/Al2O3 catalysts could be perfect candidates to be used in SER process.