Cascade adsorptive separation of light hydrocarbons by commercial zeolites

Abstract

Adsorptive separation of light hydrocarbons by porous solids provides an energy-efficient alternative to state-of-the-art cryogenic distillation. However, an optimal balance between the cost, performance and stability of the sorbent material is yet to be achieved for industrial applications. Here, we report the efficient separation of C2 and C3 hydrocarbons by a faujasite zeolite (Na-X, Si/Al = 1.23). A tandem configuration of two fixed-beds packed with Na-X affords complete dynamic separation of the ternary mixture of C2H2/C2H4/C2H6 (1/49.5/49.5; v/v/v) under ambient conditions. Pressure-swing desorption on the latter fixed-bed gives ethylene (>99.50%, 1.80 mmol g−1) and ethane (>99.99%, 1.41 mmol g−1). In situ synchrotron X-ray powder diffraction revealed the binding sites for C2H2 and C2H4 in Na-X. This study highlights the potential application of commercial zeolites for challenging industrial separations.