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Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared by incipient wetness impregnation, the Ni/Mg–Al catalyst presented much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni/Mg–Al catalyst with a Ni/Mg/Al molar ratio of 0.5:2.5:1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and internal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823–973 K. The results demonstrated that the overall conversion of CH4 and the conversion of CH4 to CO2were strongly influenced by reaction temperature, residence time of reactants as well as molar ratio of steam to methane. A classical Langmuir–Hinshelwood kinetic model proposed by Xu and Froment(1989)fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamically.
Ni / Mg-Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni / γ-Al2O3 and Ni / α-Al2O3 catalysts prepared by incipient wetness impregnation, the Ni / Mg-Al catalyst showed much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni / Mg-Al catalyst with a Ni / Mg / Al molar ratio of 0.5: 2.5: 1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and internal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823-973 K. The results performance that the the overall conversion of CH4 and the conversion of CH4 to CO2were strongly influenced by reaction temperature, residence time of reactants as well as molar ratio of steam to methane. A classical Langmuir-Hinshelwood kinetic model proposed by Xu and Frome nt (1989) fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamically.