(128a) A Comparative Parameter Study of Ni-Cu/Sio2 and Ni-Cu/Al2O3 Catalysts to Produce Cox- Free Hydrogen and Carbon Nanotubes Via Thermocatalytic Decomposition of Methane
AIChE Spring Meeting and Global Congress on Process Safety
Tuesday, March 28, 2017 - 3:30pm to 4:00pm
Thermocatalytic decomposition (TCD) of methane is the most effective route for the production of COx-free hydrogen and carbon nanotubes, simultaneously. In this work, a parametric study of the effects of the process variables including metal loading, reaction temperature, preparation method and space velocity (W/Fao) was undertaken. The effect of copper added to Ni/SiO2 and Ni/Al2O3 as a co-catalyst for the methane decomposition process has also been investigated. Copper as a nickel co-catalyst increases the methane decomposition and carbon yield over both of the catalysts. However, an increased operating temperature above 750 oC, raises the catalyst deactivation rate. At 750 °C, carbon was deposited as carbon nanofibers and resulted the highest methane conversion and carbon yield. Among the catalysts tested, the 60%Ni-10%Cu/Al2O3 catalyst showed the highest activity and stability due to the higher dispersion and stabilization of Ni particles due to the formation of nickel aluminate (NiAl2O4) spinel structure. The characterization of the fresh and spent catalysts has been carried out by using different techniques such as BET Surface area analysis, temperature programme reduction (TPR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, bulk deposition of highly uniform multi-walled carbon nanotubes with different diameters were dependent on the Ni crystalline size observed in the Ni-Cu/SiO2 and Ni-Cu/Al2O3 catalysts.