Extraordinarily large and stable methane delivery of MIL-53(Al) under LNG-ANG conditions

Natural gas (NG) is the most eco-friendly hydrocarbon fuel. However, due to its low energy density at ambient temperature and pressure, it is currently used restrictively. Recently, the coupling of liquefied natural gas (LNG) regasification and the adsorbed natural gas (ANG) charging processes has been suggested as a possible solution for expanding the uses of NG. Although metal-organic frameworks (MOFs) have been widely studied for ANG systems, few studies have been conducted on LNG-ANG systems. We evaluated the potential of MIL-53(Al) for LNG-ANG and compared it with HKUST-1 and Norit RB3. MIL-53(Al) exhibited a significantly larger deliverable capacity (262.3 v(STP)/v), which is almost close to the deliverable methane capacity target. GCMC simulations suggest that MIL-53(Al) may be transformed to a more favorable structure for methane adsorption at 159 K. Even with this flexible behavior, MIL-53(Al) was stable under repeated temperature swings between cryogenic and room temperatures. We believe that this flexible behavior of MIL-53(Al) could be applied to other gas storage and separations.