Kinetic comparison of Ni/Al2O3 and Ni/MgO-Al2O3 nano structure catalysts in CO2 reforming of methane

The kinetic characteristics of the Ni/Al2O3 and Ni/MgO-Al2O3 catalysts were investigated in CO2 reforming of methane (CRM). The reaction orders (alpha and beta) and the rate constant (k) were calculated using the non-linear regression analysis, in which the sum of the squared differences of calculated and experimental CO2 reforming of methane rates were minimized. The acquired results demonstrate that the methane partial pressure has a significant influence on the reaction rate compared to the partial pressure of carbon dioxide in CRM and the reaction rate of MgO-modified catalyst was higher than the unmodified sample. This may be due to the higher catalytic activity of Ni/MgO-Al2O3 compared to that of Ni/Al2O3 in CRM. The activation energy for CH4 consumption was higher than that of CO2. Meanwhile, adding CO and H-2 to the feed has a negative effect on the reaction rate. The experimental CH4 consumption rates for both Ni/Al2O3 and Ni/Mg-Al2O3 were fitted to some kinetic type models in order to investigate the effect of MgO modifier on the reaction kinetics of the Ni catalyst so the model with the lowest squared error was proposed as the best model describing the reaction rate.S