Carbon-molecular-sieve membranes (CMSMs) are a promising candidate for natural-gas purification because of their excellent stability, permeation selectivity, and permeability. In this project, two CMSM samples were synthesized at different pyrolytic conditions and examined for separation of N2/CH4 gas pairs. Analysis revealed that both surface diffusion and molecular sieving play important roles in gas-permeation mechanisms, which results in abnormal behaviors in the selectivities of different gas molecules.
Introduction
Because of its abundance in natural reservoirs and relatively clean-burning nature, natural gas (NG) (CH4>70%) is becoming increasingly important to the global energy supply. Raw NG contains such impurities as carbon dioxide (CO2), hydrogen sulfide (H2S), H2O, and N2, which can result in health hazards, corrosion of equipment, and lower heating value.
