Hydrogen production by autothermal reforming of kerosene over MgAlO _x-supported Rh catalysts

Autothermal reforming (ATR) of kerosene for hydrogen production was performed on the MgAlO_xsupported Rh catalysts at LHSV of 15-25, S/C of 2.5, O/C of 0.5, at 101 kPa. Sphere-shaped supports with high compressive ultimate strength (0.90 MPa) were obtained from MG-30 hydrotalcite core (∼3 mm) by thorough heat treatment before impregnation of rhodium. Rhodium was loaded by pore-filling impregnation selectively to the surface of the sphere-shaped supports, confirmed by electron probe microanalysis. Stability tests on the prepared catalysts were performed, focusing on the small amount of C₂-C₃ hydrocarbons, concentrations of which reflect the catalytic activity and stability; i.e., low rates of C₂-C₃ olefin formation correspond to high activity of the catalysts. The reactor was designed to measure temperature profiles and gas distributions within the reactor (inner diameter ∼21.0mm) and the catalyst bed (length 100 mm). The ATR reactions occur starting with an exothermic combustion of hydrocarbons, followed by an endothermic reforming. The maximum temperature reached ∼1200 K at the inlet of the catalyst bed and decreased to ∼1020K towards the end of the catalyst bed. Among investigated catalysts, the catalysts treated in air at 1223 K gave the best performance for ATR of kerosene, giving H₂ production reaching 60% of the exit gas. The concentration of the main byproduct, C₂H₄, over the optimized catalyst was lower than 0.03% at the exit of the reactor for 50 h of the study. The catalyst showed high tolerance to coking and high stability even at LHSV of 25 and daily start-up and shut-down (DSS) cycles, meeting practical requirements for the ATR catalysts.