Extract Propane and Ethane from Methane on Ultramicroporous Carbon
Adsorbent with Record Selectivity
Abstract
Separation of light hydrocarbon mixtures and extraction of C3H8 and C2H6
from CH4 are of significant importance in natural gas purification and
upgrade. Microporous carbon adsorbents are promising in light
hydrocarbons separation, but to fabricate uniform ultramicropores to
boost separation selectivity remains challenging. Herein, we fabricated
a series of poly(vinylidene chloride) resins-derived ultramicroporous
carbon adsorbents with relatively uniform pore size (5.2-5.3 Å) by
activator-free pyrolysis. The optimal C-PVDC-800 exhibited record-high
IAST selectivity of C3H8/CH4 (3387) and C2H6/CH4 (75) as well as Henry’s
selectivity of C3H8/CH4 (369) among all reported adsorbents under
ambient conditions, combined with ultrahigh uptake of C3H8 (3.9 mmol
g-1, 0.05 bar) and C2H6 (2.67 mmol g-1, 0.10 bar) at low partial
pressures and 298 K. More importantly, fast gas adsorption kinetics were
realized, favorable in fixed-bed adsorption applications. Breakthrough
experiments and cycling tests further confirm the superb separation
performance of extraction of C3H8 and C2H6 from CH4.