Regeneration of Deactivated Mo/ZSM-5 Catalyst for Shale Gas Dehydroaromatization: Coke Removal Modeling and Catalyst Stability

초록

This study aims to analyze the regeneration of Mo/HZSM-5 catalysts deactivated during shale gas dehydroaromatization, with a focus on the apparent kinetics of coke removal. Thermogravimetric analysis and single--particle kinetic modeling were employed to estimate reaction rate constants under varying O2 concentrations, temperatures, and particle sizes. The model successfully predicted the time required for coke elimination across different pellet diameters. Experimental results showed that coke was completely removed at high O2 concentrations; however, the activity of Mo2C active sites was not restored due to dealumination and the formation of Al2(MoO4)3. To ensure stable regeneration, O2 concentration and flow rate were optimized to control heat release. Long-term cycle tests demonstrated that regeneration at 1.5% O2 provided better catalyst stability than at 10%. Finally, the developed coke-removal model was applied to fixed-bed, moving-bed, and fluidized-bed reactor configurations, revealing differences in allowable O2 concentration, temperature profiles, and coke removal rates depending on gas/solid flow patterns. This work uniquely integrates kinetic modeling with stability evaluation, offering practical guidelines for selecting regeneration strategies across reactor types.

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