Mathematical model and energy analysis of ethane dehydration in two-layer packed-bed adsorption

The 3A zeolites are excellent adsorbents for industrial-scale gas dehydration because of the low energy required for regeneration and ease of operation. A computational study of the dehydration of an industrial feed stream containing ethane and water was performed using an in-house code that included an appropriate equilibrium adsorption isotherm. The validated computational model was used to examine the impact of particle size on the process dynamics and the corresponding pressure drop. The water concentration along the adsorption column was also investigated. To increase the process capacity, the packed adsorption bed was divided into two distinct layers, which were operated with different particle sizes. The length of each layer was determined by a parametric study. The best breakthrough time, i.e., 107,800 s, at the allowed pressure drop was obtained when the lengths of the first and second layers were 4.5 and 1 m, respectively. The results showed that the new two-layer adsorption bed could save around 33.8% in total energy requirement in comparison to that of a single bed. (C) 2019 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.