Recovery of helium from natural gas using MFI membranes

The development of more efficient technology for the production of helium from natural gas is pressing as the current resources are dwindling. In the present work, ultra-thin MFI membranes were evaluated for the separation of an equimolar CH4/N2/He mixture in a wide temperature range 120-293K. The membrane was highly selective towards CH4 and N2 at all the investigated conditions, which resulted in a helium rich retentate. The observed selectivity should be a result of selective adsorption of CH4 and N2. A maximum (CH4+N2)/He separation factor of 152 was observed at 153 K and a feed pressure of 3 bar and a permeate pressure of 0.2 bar. At these conditions, separation factors were 265 and 38 for CH4/He and N2/He, respectively, and the CH4 and N2 fluxes were 1.12 and 0.16 mol/(m2 center dot s), respectively. To the best of our knowledge, these are the best results reported in the open literature for the recovery of helium from natural gas using membrane technology. The high selectivity and flux indicated that the ultra-thin MFI membranes are a promising candidate for efficient helium production from natural gas.