A Two Property Catalyst/Sorbent Pellet Design for the Sorption-Enhanced Steam–Methane Reforming Process: Mathematical Modeling and Numerical Analysis

In the present study, the performance of a combined catalyst/sorbent pellet design for the sorption-enhanced steam– methane reforming process has been numerically investigated. The mathematical pellet model formulated for the process describes the evolution of species mole fractions, pressure, total concentration, temperature, mass and heat fluxes, and convection within the voids of the porous pellet. The mass diffusion fluxes are described according to the Maxwell– Stefan and dusty gas models and the effective diffusivities are described employing the parallel pore model. In addition, models proposed in the literature for void fraction changes and product layer diffusion resistance are adopted.The effectiveness factor is a convenient parameter used in modeling and simulations of chemical reactors indicating the relative importance of diffusion and reaction limitation. In this study, the simulation results presented in terms of effectiveness factors reveal the following noticeable findings for the two pellet diameters analyzed: (i) Knudsen diffusion is significant for the operation conditions set for the simulation study. Hence the pore size distribution within the pellet is significant. (ii) Structural changes within the pellet affects the pellet capacity.