(532bm) Regeneration Strategies to Maximize Catalyst Stability and Productivity for Methane Dehydroaromatization Via Periodic-Switch, Pulse Feeding, and Catalysts Integration
AIChE Annual Meeting
Wednesday, November 16, 2022 - 3:30pm to 5:00pm
Methane Dehydroaromatization (MDA) is a very attractive direct reaction to upgrade methane to valuable products with no CO2 emission as part of the reaction stoichiometry. The MDA process has many challenges hindering its commercialization which include the thermodynamic limitations resulting in a maximum single-pass conversion of only about 10 to 15%, and the rapid deactivation and stability, which is the focus of this work. This work is centered around maximizing the production rate of aromatic/benzene by minimizing the regeneration time to the least possible while maintaining the same operating condition. This is carried out via two approaches. Exploring different types of unconventional regenerating modes using pulse and periodic feeding using CO2 as oxidative regeneration molecule, and H2 as reductive regeneration. The second approach is coupling the MDA catalyst with another upstream catalyst that has reaction effluent that could regenerate, maintain, or even boost the MDA catalyst's long-term stability. The second catalyst used in this integration is the oxidative coupling of methane (OCM) catalyst. This is another valuable direct methane conversion reaction to make ethylene, H2, CO, and CO2 all of which are possible regeneration molecules, and or intermediates of the MDA reaction. The experiments are carried out in a catalytic fixed bed experimental setup combined with automated switching valves to change between the feeds. In the case of catalyst integration, the MnWNa/Al2O3 catalyst for OCM was placed above the Mo/HZSM catalyst for MDA separated by quartz wool. Various parameters were tested in this study including the different regeneration modes of pulsing and periodic. The outcomes from this ongoing experimental investigation will be presented along with opportunities and limitations for the development of a new regeneration strategy to improve the long-term stability of the MDA process.