Simulation and experimental demonstration of helium purification from He/N2 mixtures by pressure swing adsorption

Terrestrial helium is an indispensable non-renewable resource used in medicine, space, electronics, and nuclear research. This paper reports a high-pressure five-step pressure swing adsorption (PSA) cycle using Zeolite 5A for purification of He from dilute He/N2 mixtures. A Dual-Site Langmuir (DSL) model fitted both the low-pressure N2 and high-pressure N2 isotherm data. Dynamic column breakthrough (DCB) experiments were used to confirm volumetric equilibrium loadings. The DCB model predicted the experimental breakthrough curves for a wide range of feed compositions (100% N2, 74.5% N2, and 51.5% N2) and feed pressures (1 bar and 11.2 bar). A large experimental campaign studied the impact of various operating conditions on the He purity and recovery achievable from the PSA process. The study showed that a single-stage PSA experiment could enrich He up to 13% purity with greater than 90% recovery from a feed containing 1% He. Helium purity of 95% and a recovery of 90% can be achieved from a feed containing 10% He. All trends were predicted well by numerical simulations. A multi-objective optimization was performed to maximize helium purity and recovery for various He feed compositions. The study also showed that points from the Pareto curve can be realized experimentally. •Helium is a precious non-renewable resource with widespread applications.•Single-stage PSA enriched He from 1% in feed to a 13% product at >90% recovery.•He purity of 95% purity at 90% recovery achieved from a feed containing 10% He.•5-step light product PSA cycle produces He at nearly the feed pressure.•Extensive experiments confirm numerical optimization.