关键词: Carbon/methane separation, Nitrogen/methane separation, CHA membrane, Natural gas purification

Abstract: SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis. Separation performances of SSZ-13 membranes in CO₂/CH₄ and N₂/CH₄ mixtures were enhanced after synthesis modification. Single-gas permeances of CO₂, N₂ and CH₄ and ideal selectivities were recorded through SSZ-13 membranes. The effects of temperature, pressure, feed flow rate and humidity on separation performance of the membranes were discussed. Three membranes prepared after synthesis modifications had an average CO₂ permeance of 1.16×10^-6 mol·(m²·s·Pa)^-1 (equal to 3554 GPU) with an average CO₂/CH₄ selectivity of 213 in a 50 vol%/50 vol% CO₂/CH₄ mixture. It suggests that membrane synthesis has a good reproducible. The membrane also displayed a N₂ permeance of 1.07×10^-7 mol·(m²·s·Pa)^-1 (equal to 320 GPU) with a N₂/CH₄ selectivity of 13 for a 50 vol%/50 vol% N₂/CH₄ mixture. SSZ-13 membrane displayed stable and good separation performance in the wet CO₂/CH₄ mixture for a long test period over 100 h at 348 K. The current SSZ-13 membranes show great potentials for the simultaneous removals of CO₂ and N₂ in natural gas purification as a facile process suitable for industrial application.

Key words: Carbon/methane separation, Nitrogen/methane separation, CHA membrane, Natural gas purification