Process-based evaluation of adsorbents: effect of CMS pellet size on N2-PSA performance

Abstract

The process-based evaluation of adsorbents is considered the most foolproof method with respect to a particular application, as it provides data about the separation effectiveness in authentic operating conditions. This paper presents empirically obtained performance results of the kinetically-controlled air separation on multiple carbon molecular sieves carried out in a twin-bed pressure swing adsorption unit. The effect of adsorbent pellet size on nitrogen productivity and air demand is studied at different product purity levels (10–10,000 ppm O2 of the residual oxygen concentration), operating temperatures (25–45 °C), and half-cycle times (35–70 s). The selected process conditions correspond to the majority of practical applications. Guidelines for the suitable particle size depending on the desired nitrogen purity are given.