A nanoporous hybrid membrane for natural gas upgrading
A French-Saudi consortium including researchers from the Institut Charles Gerhardt Montpellier (Université Montpellier/CNRS/ENSCM) and the Centre de Research Advanced Membranes and Porous Materials (KAUST University) has developed a new crystalline porous hybrid material which, when processed as a membrane, purifies natural gas by selectively capturing not only nitrogen but also carbon dioxide from methane with exceptional selectivity and permeability. Published in the journal Nature on June 23, 2022, this work opens up the possibility of more efficient industrial processes for purifying natural gas and biogas.
In today's energy context, the valorization of natural gas, which represents more than 25% of the world's energy sources, is of major interest for its use in domestic installations or in industry. Natural gas sources, essentially contaminated with nitrogen and carbon dioxide, are currently purified on an industrial scale using energy-intensive cryogenic distillation processes, which represent a significant economic cost in the exploitation of this energy source. It is therefore becoming urgent to consider alternative, more efficient and less costly purification technologies.
A French-Saudi consortium has designed a porous, crystallized hybrid material, commonly known as a Metal-Organic Framework (MOF), formed by the association of a metal oxide connected by an organic ligand, capable of preferentially fixing nitrogen to methane. This solid features nano-sized cages accessible through triangular windows whose size and shape have been shaped to allow the passage of nitrogen, a linear molecule, and exclude access for methane, a spherical molecule.
This new material has been shaped into a membrane that achieves exceptional nitrogen/methane separations and permeabilities compared with other polymeric and zeolite membranes tested to date under real operating conditions. This process reduces methane purification costs by over 70% compared with cryogenic processes commonly used in industry.
Applicable to the selective capture of other contaminants such as carbon dioxide, the design of this new membrane, the result of a synergy between complementary disciplines (molecular modeling, materials development, membrane manufacturing and performance testing), opens up new prospects on an industrial scale for the valorization of natural gas and biogas. And beyond that, it could well revolutionize the problem of gas purification, which represents major challenges in the energy and environmental fields (improvement of air quality, production of pure hydrogen, etc.).
