(173l) Carbon Molecular Sieves for Binary Permeation of N2/CH4 and CO2/CH4 Gas Pairs

Carbon Molecular Sieve Membrane (CMSM) is derived from the pyrolysis of polymeric precursors. It possesses good mechanical strength, inert surface chemistry, and above all, high permeability and selectivity. It is one of the ideal candidates for the purification of natural gas (NG). The research aims at the removal of N₂ out of NG stream by using membrane technology. It compares favorably to the traditional method of cryogenic distillation at about -180 ⁰C, which is energy intensive and costly. For N₂/CH₄ gas pair, CMSM 700 at 20 ⁰C showed a good perm-selectivity of ~ 16.35 with N₂ permeability of 2.370 Barrer and CH₄ permeability of 0.145 Barrer at 250 KPa. The membrane is working more on sieving mechanism than surface diffusion mechanism for N₂/CH₄ gas pair. For CO₂/CH₄ gas pairs, CMSM 600 showed very good selectivity of 129.30 and CO₂ and CH₄ permeability of 342.64 and 2.65 Barrer, respectively at the permeation temperature of 20 ⁰C.