Xenon Recovery from Natural Gas by Hybrid Method Based on Gas Hydrate Crystallisation and Membrane Gas Separation

Abstract The present study deals with a comprehensive experimental evaluation of a unique hybrid method based on gas hydrate crystallisation and membrane gas separation, proposed as an alternative approach to Xenon (Xe) recovery from natural gas. The following operational modes were investigated: pressure-dropping mode, the constant pressure mode, continuous mode, continuous membrane-gas hydrate mode. The simulation was performed on a model gas mixture (CH4 (94.85 mol.%) / CO2 (5.00 mol.%) / Xe (0.15 mol.%)), which contains natural gas components, with an addition of a kinetic gas hydrate promoter – sodium dodecyl sulfate (0.30 wt.%) at 272.15 and 274.15 K for 4 hours in a pilot-scale gas hydrate crystalliser. The most optimal separation mode has been determined for Xe recovery from natural gas. The experimental efficiency has been evaluated based on the gas hydrate distribution coefficients, separation factors, and the gas hydrate recoveries values. The maximum Xe gas hydrate recovery is 93.05% based on the continuous membrane-gas hydrate separation at 272.15 K. The maximum mixture gas hydrate recovery is 40.05% based on the constant pressure separation at 272.15 K. Thus, the choice of the optimal separation mode for Xe recovery from natural gas is determined by the required degree of natural gas purification.