The kinetics of methane partial oxidation over Ni/MgO/a-Al2O3 catalyst using spinning basket reactor

• Main Author: Muna, Izza Aliyatul
• Format: text
• Language: English
• Published: Animo Repository 2006
• Subjects: Methane; Oxidation; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/3564; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/10402/viewcontent/CDTG004345_P__1_.pdf
• Institution: De La Salle University

Partial oxidation is considered to be an attractive economical method to convert methane to synthesis gas. Although it seems to be economically attractive, the industrial application of catalytic partial oxidation is still a big challenge. It is necessary to develop appropriate catalysts and design reactor suited to them. Knowledge of the reaction rate expression is important to design chemical reactor for industrial production. Reaction rate expression is also important for optimizing the production and to define the safety limits for operation. In this study, the effect of composition, flowrate and reaction temperature on the reaction rate using Ni/MgO/a-Al2O3 catalyst were investigated in the methane partial oxidation process. A spinning basket reactor was used to conduct the reaction. The catalyst used was prepared by loading 0.84% Ni on Al2O3 support with NiO/MgO molar ratio 2 using precipitation method. Information regarding the surface morphology of the test catalysts was determined using the SEM-EDX. The present nickel, nickel oxide, magnesium oxide, and alumina crystal was determined using the X-Ray Diffraction (XRD). The pore size and surface area were also determined using the BET Analyzer. Space velocity of the feed gas affected the reaction rate. When the space velocity increased from 8000 to 14000 ml/h.gcat, CH4 and O2 conversion decreased. The CH4 and CO reaction rate slightly decreased as space velocity increased. However, oxygen disappearance rate increased. The CH4:O2 ratio in feed affected the CH4 and O2 conversion. CH4 conversion decreased as CH4:O2 ratio in the feed increased. On the other hand, O2 conversion increased significantly with increasing CH4:O2 ratio. It was found that CH4 and CO reaction rate increased as CH4 concentration increased. However, the decrease of O2 concentration in the feed results in decrease of O2 disappearance rate. De La Salle University v The CH4 and O2 conversion and reaction rate significantly increased when reaction temperature was increased from 600 to 750°C for constant space velocity and constant CH4:O2 ratio in the feed. The rate equations were derived for partial oxidation of methane to synthesis gas on Ni/MgO catalyst supported on a-Al2O3 based on the mechanism that both methane and oxygen are adsorbed on the catalyst with dissociation of oxygen, and the assumption that surface reaction are rate controlling step.