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

Authors

• Zahra Alipour ¹
• Fereshteh Meshkani * ^{1, 2}
• Mehran Rezaei ^{1, 2}

1. Department of Chemical Engineering, University of Kashan, Km 6 Ravand Road, Kashan, Post Code: 87317-51167, Iran.
2. Institute of Nano Science and Nano Technology, University of Kashan, Km 6 Ravand Road, Kashan, Post Code: 87317-51167, Iran.

Abstract

The kinetic characteristics of the Ni/Al₂O₃ and Ni/MgO-Al₂O₃ catalysts were investigated in CO₂ reforming of methane (CRM). The reaction orders (α and β) 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 H₂ 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.

Keywords

• Kinetics
• Ni catalysts
• CO2 reforming of methane
• Synthesis gas