Separation of Xenon from Noble Gas Mixtures of Argon, Krypton, and Xenon Using Gas Hydrate Technology

Separating and purifying noble gases from atmospheric air require highly efficient separation processes to achieve commercially viable quantities. Cryogenic distillation is a widely employed method for noble gas separation, which is an energy-intensive technology. This study proposes a cost-effective method for separating and purifying xenon from the gas mixture of argon, krypton, and xenon based on multistage gas hydrate technology. Experimental measurements were conducted using a 52 cm(3) stainless steel equilibrium cell to obtain new hydrate dissociation data for gas mixtures containing argon, krypton, and xenon. These measurements were accompanied by a predictive thermodynamic model, which exhibited a maximum absolute relative deviation of 1.4%. Furthermore, novel experimental data were obtained for the composition of hydrate-vapor phases for the system of argon + krypton + xenon. The data included different component compositions, varying amounts of xenon, and a thorough analysis of hydrate and vapor equilibrium phases using gas chromatography. These findings offer valuable insights into the utilization of gas hydrates for separating xenon from a mixture of argon, krypton, and xenon. The experimental results show that the concentration effect of xenon in the captured hydrate lattice has the most significant increase in the first and second hydrate stages. For a mixture of 40.7 mol % argon, 33.6% krypton, and 25.7% xenon, a concentration increase from 25.7 to 80.4% of xenon was achieved using two hydrate formation and dissociation stages. Compared with cryogenic distillation for the separation of these gases to achieve Xe at high purities, the results from this work reveal that the hydrate-based separation method presents a 20% energy cost advantage over cryogenic distillation.