Helium recovery from natural gas over CC3 membranes

Abstract

Although helium is a valuable inert gas available in abundance in the earth's atmosphere, the major source of helium is from natural gas reservoirs. Membrane based separation processes pose many advantages like being cost effective and non-energy intensive. In this current study, we have successfully demonstrated the synthesis of continuous Porous Organic Cage: CC3 membranes to separate equimolar helium methane mixture with permeance of 4.45 × 10⁻⁷ mol/ (m²s Pa) and separation selectivity ($\alpha )$ as high as 8. We also compared the diffusion coefficients of the gases through the membrane to evaluate the dominant mechanism for separation. Lastly, we compared the performance of our membranes to the state-of-the-art membranes with the help of a Robeson plot and found that our membranes outperformed the upper bound.