Methanol-to-hydrocarbon (MTH) processes over H-ZSM-5 zeolites: New kinetic modeling methodology using forced periodic operation and improvements in catalyst formulation

Abstract

This Thesis focuses on the implementation of novel catalyst formulations selective towards aromatics and innovative reactor operation methodologies towards the development of a unified kinetic model for Methanol-to-hydrocarbon (MTH) reaction over H-ZSM-5 zeolite-based catalysts. For that purpose, three H-ZSM-5 zeolites of different Si/Al ratio (and thus, different acidity) have been used under both Methanol-to-olefins (MTO) and Methanol-to-aromatics (MTA) conditions. Under MTO conditions, a new kinetic modeling methodology based on forced periodic operation has been developed, focused on reducing the experimental workload required to develop robust lump-based kinetic models. Under MTA conditions, new catalysts have been tested, aimed at increasing the selectivity towards aromatics. In addition, a global kinetic model for MTH has been developed, which can be applied under both MTO and MTA conditions. This global model has been then decoupled from the specific catalyst, by relating the kinetic parameters that define it to the acidity of the catalyst, thus resulting in a unified, acidity-based kinetic model. The proposal of a unified acidity-based model increases the versatility for the simulation and design of reactors with different operating strategies, improving the flexibility for responding to market changes more dynamically. Moreover, the methodology here presented is applicable not only for MTH, but also to other reaction networks.