The 3A zeolite is widely used as an excellent adsorbent for industrial scale gas dehydration, due to its low energy demand for regeneration and ease of operation. The dehydration process of an industrial feed stream of ethane and water was numerically studied using an in-house code that included an appropriate equilibrium adsorption isotherm. The validated computational model was used and the impact of particle size on the process dynamics and the corresponding pressure drop were studied. In addition, the mass transfer along the adsorption column was evaluated. To increase the process capacity, the packed adsorption bed was divided into two distinct layers operating with different particle sizes and the length of each layer was determined according to the performed parametric study. The best breakthrough time (of 107,800 s) at the pressure drop allowance was obtained for the case that the length of first and the second layers were 4.5 m and 1 m, respectively. Finally, it was found that the new two-adsorption bed can save around 33.8 % in total energy requirement in comparison with the single size bed.
