A Digital Twin for Methane Catalytic Cracking in a Fluidized Bed Reactor

Abstract

Methane catalytic cracking is a promising clean alternative for hydrogen production, generating only hydrogen and solid carbon, thereby minimizing environmental impact. Unlike conventional methods, this technology enables hydrogen production without additional hydrocarbon emissions. However, an efficient catalyst is required to facilitate the reaction at moderate operating temperatures (500–700°C), reducing operational costs and allowing for potential integration with solar energy. To enhance both mass and heat transfer, a bubbling fluidized bed reactor (FBR) was employed to conduct the methane cracking process. This study presents the development of a three-phase FBR model using a highly active zinc-promoted nickel catalyst (50Ni-5Zn/USY) on ultra-stable Y (USY) zeolite. The model was designed to predict the reactor’s performance under different operating conditions, providing essential insights for scaling up the process for industrial applications. To accurately simulate the system, both kinetic and mechanistic models were developed: The mechanistic model describes the hydrodynamic properties of the fluidized bed, bubble characteristics, and the mass transfer of methane and hydrogen across the three phases. The kinetic model was formulated to characterize the reaction rate. The most suitable kinetic model suggests that the reaction follows a dissociative adsorption mechanism, with the first hydrogen abstraction from methane identified as the rate-determining step. This was validated against experimental data, where parameter estimation was carried out to predict the Arrhenius rate coefficients. The findings of this model significantly enhance the understanding of methane catalytic cracking, providing key insights for optimizing process conditions and demonstrating the feasibility of scaling up this technology for industrial hydrogen production with minimal environmental impact.