초록 |
Oxygen is applied to various fields such as chemical processing, medical applications, and fuel cells. Recently, portable oxygen generators to provide oxygen for patients with COVID-19 and purify indoor air are highly expanding. Therefore, the small-scale O2 pressure swing adsorption (PSA) unit pays great attention to producing higher than 90% O2 purity from the air. Zeolites can selectively adsorb nitrogen to oxygen. The same type of zeolite crystal generally shows the same adsorption capacity. It was reported that zeolite LiX has the highest adsorption capacity and selectivity in air separation. However, when it is pelletized, the performance of the zeolite LiX pellet is highly dependent on the quality of pelletization. In this study, various commercial zeolite LiX pellets were evaluated with their textual properties and the adsorption performance of N2 and O2 to select an optimal adsorbent for a small-scale O2 PSA. The isotherms of N2 and O2 on zeolite LiX pellets were measured at 293 K, 308 K, and 323 K, and the uptakes of N2 were compared. The results were analyzed with the physical properties measured by N2 isotherm at 77 K and CO2 isotherm at 273 K. |