Developed Mathematical Model for SAPO-34 Core-Shell Adsorbents in the Adsorption Process of CO2 from Natural Gas

Abstract

The core-shell adsorbent made of Silico alumina phosphate-34 fine layer on the ceramic particles is investigated for the separation of CO2 from methane and the adsorption efficiency is studied by a developed mathematical model. The multi-component dynamic adsorption processes is modelled by mass balances and energy balance equations in the bulk gas phase and porous particles, simultaneously, considering concentration and temperature variations. The predicted CH4 and CO2 breakthrough curves were calculated and compared with the experimental results and good agreement was observed between the model and experiment. The packed bed with core-shell adsorbent showed longer breakthrough time, shorter mass transfer zone, lower bed temperature increase, sharper breakthrough curve, and a higher degree of column utilization than the bed filled with the ordinary adsorbent. The developed model was implemented in parametric study of the core-shell adsorbent with different shell thicknesses. The results suggest that the high diffusion resistance of SAPO can be significantly reduced by the reduction of the shell thickness and higher efficiency would be achieved, especially when the intra-particle diffusion resistance is high and/or the higher feed flow rate is required to pass through the bed in the industrial usage.