Production of Argon from an Oxygen-Argon Mixture by Pressure Swing Adsorption

Kinetic selectivity of four potential adsorbents for the separation of oxygen-argon mixture by pressure swing adsorption (PSA) was compared based on adsorption equilibrium and kinetics measured in the linear range. In the chosen adsorbent, Takeda II carbon molecular sieve (CMS), the measurements were extended up to 6 atm pressure. Appropriate models were developed that explained the measured data and gave necessary parameters for subsequent use in PSA simulation. PSA experiments were conducted to concentrate argon from a 95:5 (mole ratio) oxygen-argon mixture using a single-bed, three-step cycle operated in 0-3 atm pressure range. PSA simulations were conducted using a bidispersed adsorbent model and a dual transport resistance with strongly concentration-dependent thermodynamically corrected transport parameters in the CMS micropores. It was a kinetically controlled separation with a high proportion of faster component in the feed mixture. The performance of the single-bed, three-step vacuum cycle at different operating conditions was systematically studied using the PSA simulation model validated with experimental results.