Detailed Investigation of Different Diffusion Models for Reactive Catalytic Systems in Isolated Particles and Slender Packed Beds

Packed bed reactors are found abundantly in the chemical industry in applications ranging from product synthesis to effluent treatment and catalytic combustions. While there exists considerable number of studies in terms of flow dynamics, detailed investigations into reactive systems are still scarce. For systems where different components highly interact with each other or with sequential reactions, it is important to accurately represent all species. In this work, we get a step closer to the multi-component modeling of reactive processes in slender packed beds. We will compare different diffusion models like the Dusty Gas Model (DGM) and Fick with Darcy flow (F+D) to investigate when we can make the trade-off between the better accuracy of DGM and lower computational demand of F+D. We will extend the usual comparisons by considering temperature and conjugate transport. The obtained knowledge will be applied to study the CO2 methanation in a slender packed bed where we will vary reactor operating conditions to investigate the effect on mass (and heat) transport and the overall reactor performance. The work presents the models which are necessary to accurately represent reactive, multi-component packed beds and provides insight on the reactor performance as a function of mass transport behavior.