Detailed Reaction Mechanisms for the Oxidative Coupling of Methane over La2O3/CeO2 Nanofiber Fabric Catalysts

摘要

We develop and validate detailed reaction mechanisms to represent the oxidative coupling of methane (OCM) over a La2O3/CeO2 nanofabric catalyst. The reaction mechanism includes 39 reversible gas-phase reactions and 52 irreversible surface reactions between 22 gas-phase species and 11 surface species. We use a model-based interpretation of spatially resolved concentration and temperature profiles measured by using a laboratory-scale packed-bed reactor. The reaction mechanisms are validated for inlet feed compositions in the range of 7 = CH4/O-2 = 11. The results are supported by a reaction pathway analysis that provides insight into the relative contributions of the gas-phase and surface reactions to form the desired C2+ and the undesired COx products. The results provide new quantitative insights into the complex nature of the OCM chemistry, which can assist practical process and reactor development.