C2/C3 Hydrocarbon Separation by Pressure Swing Adsorption on MIL-100(Fe)

The main objective of this work is the separation of 0.30/0.70 ethane/propane and 0.30/0.70 ethylene/propane by pressure swing adsorption (PSA) on MIL-100(Fe). The metal–organic framework MIL-100(Fe) was proposed as a potential adsorbent due to its high C2/C3 selectivity. Since adsorption equilibrium data are essential for the process design, the adsorption isotherms of ethane, ethylene, and propane were measured at 323, 373, and 423 K by a gravimetric method. Fixed-bed experiments were conducted at 0.5 SLPM, 323 K, and 150 kPa feed conditions on a bench-scale vacuum PSA (VPSA). Equilibrium and dynamic studies confirmed the preferential adsorption of propane over ethane and ethylene, with a high adsorption separation factor. Two five-step VPSA cycles with two different feed compositions, 0.30 ethane/0.70 propane, and 0.30 ethylene/0.70 propane, at 323 K and 150 kPa on MIL-100(Fe) were designed and performed experimentally. The performance parameters demonstrated the high viability of the proposed processes, since ethane purity of 99.5% was achieved, and with a high ethane recovery (86.7%). In the same cycle, 99.4% of propane was recovered with 97.0% purity. In cycle scheme 2, an ethylene purity of 100.0% was achieved. The propane was 100% recovered with a purity of 94.7%.