Large-area and high-performance SSZ-13 membranes for N2/CH4 separation

Separating N2 from CH4 is challenging but critical for the purification of unconventional natural gas. Herein, large-area and high-quality SSZ-13 membranes were reproducibly produced on the 50-cm-long tubular alumina supports for the N2/CH4 separation for the first time. The effects of test parameters such as pressure drop, temperature, feed flow rate, water vapor and hydrocarbon impurities on separation performance of the membrane were investigated. A mathematic model for concentration polarization (CP) index was established to evaluate the extent of CP. The CP can be released by decreasing feed pressure and increasing feed flow rate. Separation performance of semi-industrial-scale SSZ-13 membrane was superior to most small-area zeolite membranes. The membrane showed excellent stability in the presence of 5-10% ethane and propane and saturated water vapor. Selectivity and permeance of the membrane can be restored to its initial values when the impurities are removed. The up-scaling and high-quality membranes have the great potentials for the industrial application in natural gas purification.