Ethylene/propylene separation using mixed matrix membranes of poly (ether block amide)/nano-zeolite (NaY or NaA)

Generally, the energy and capital intensive cryogenic distillation process is applied to separate light olefins. To lower the cost of light olefin production, mixed matrix membranes (MMMs) incorporating nano-zeolite (NaY or NaA) into a rubbery poly (ether block amide) (PEBA 2533) were fabricated to separate a propylene/ethylene mixture. The effect of additive content and kind, MMM thickness, and operating temperature and pressure on the separation performance of the synthesized membranes for a propylene/ethylene mixture were investigated. As an additive, NaY was found to be more effective than NaA. Interestingly, the result of pure gas adsorption was consistent with the permeation performance of the membranes. Membranes with 6 wt% NaY showed the highest C3H6/C2H4 selectivity in all synthesized membranes (3 wt%–10 wt%), on which, the C3H6/C2H4 selectivity was increased from 2.3 to 13.1, the permeability of propylene increased from 194 barrer to 262 barrer and the permeability of ethylene decreased from 85 barrer to 19.8 barrer when the propylene concentration in feed mixture increased from 10 mol% to 80 mol% at −35 °C and 0.2 MPa. This membrane has the potential to separate propylene and ethylene in industry, and this work will push forward the membrane separation process for olefin production.