METHANE STORAGE AT HIGH PRESSURE USING BREATHING METAL-ORGANIC FRAMEWORKS

Abstract

In order to make natural gas storage energetically affordable, it is possible to confine the gas in porous materials. One of the key criteria is the ability of the material to retain an important volume of gas at high pressures and deliver this amount at low pressures. This property is enhanced for some breathing Metal-Organic Frameworks (crystals composed of metal clusters linked by organic ligands). Indeed these structures can change their crystal phase during adsorption and desorption processes, resulting in several adsorption/desorption steps.

This study focused on the properties of MIL-53(Al)-NH2, during methane adsorption. The high pressure isotherms that we have realized prove the existence of three different phases (very narrow pores at low pressures, narrow pores at medium pressures and large pores at high pressures). Tuning the triggering of these different phases can allow us to increase the deliverable capacity (up to almost double of its value). Different strategies have been used to achieve such a purpose: pre-adsorption at high pressure, cycling pressure during adsorption, or mixing ligands during the synthesis of the MOF.