Adjusting the Si/Al ratio of high silica zeolites for efficient ethane and ethylene separation

The economically efficient separation of ethane (C2H6)/ethylene (C2H4) presents challenges in the petrochemical industry, and the use of traditional adsorbents zeolite provides a reliable guarantee for maintaining the economic viability of adsorption separation technology. In this study, we investigate the impact of different silica-alumina ratios (SiO2/Al2O3 = 40, 500, and 1500) of high silica zeolites ZSM-11 on the C2H6/C2H4 separation performance to develop efficient C2H6 selective adsorbents. The results show that the C2H6 adsorption capacity and C2H6/C2H4 selectivity of ZSM-11 increase as the silica-alumina ratios increases. The pure silica zeolite (ZSM-11(1500)) exhibits the highest adsorption capacity for C2H6 (59.19 cm3/g) and the highest selectivity for C2H6/C2H4 (2.04), which were superior to ultra-high silica sample (ZSM-11(500)) (55.06 cm3/g and 1.62, respectively) and high silica sample (ZSM-11(40)) (47.28 cm3/g and 1.23, respectively), at 273 K and 1 bar. The mixed gas breakthrough experiments results show that pure silica sample has outstanding C2H6/C2H4 separation ability. The PSA simulation calculated data demonstrating promising potential for industrial applications. Importantly, this separation performance remains unaffected even in the presence of H2O.