A- and B-Site Substituted Lanthanum Cobaltite Perovskite as High Temperature Oxygen Sorbent. 2. Column Dynamics Study

Abstract

Perovskites, with exclusive selectivity for oxygen over nitrogen, offer significant promise as potential high temperature adsorbents for air separation. Results from fixed bed, breakthrough experiments at 500 °C on two perovskite samples having compositions SrCo0.5Fe0.5O3-δ and La0.1Sr0.8Ag0.1Co0.5Fe0.5 O3-δ that were short-listed in our previous thermogravimetric study are presented here. The oxygen equilibrium capacities obtained from the breakthrough runs compared well with those from the thermogravimetric data. A numerical simulation model featuring axially dispersed plug flow with independently estimated axial dispersion coefficient, Langmuir isotherm fitted to the measured equilibrium data, and a linear driving force rate expression for mass transfer with a large rate constant was developed that effectively captured the essential features of the measured column dynamics.