A nanoporous hybrid membrane for natural gas upgrading
A Franco-Saudi consortium comprising researchers from the Charles Gerhardt Montpellier Institute (Montpellier University/CNRS/ENSCM) and the Center for Research on Advanced Membranes and Porous Materials (KAUST University) has developed a new crystalline porous hybrid material which, when used in membrane form, 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 paves the way for more efficient industrial processes for purifying natural gas and biogas.
In the current energy context, the utilization of natural gas, which accounts for more than 25% of global energy sources, is of major interest for its use in domestic installations or in industry. Natural gas sources, which are mainly 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 purification technologies that are more efficient and less costly.
A French-Saudi consortium has designed a crystallized porous hybrid material, commonly known as a metal-organic framework (MOF), formed by combining a metal oxide connected by an organic ligand, capable of preferentially binding nitrogen rather than methane. This solid has nanometric-sized cages accessible through triangular windows whose size and shape have been designed to allow the passage of nitrogen, a linear molecule, while excluding methane, a spherical molecule.
This new material has been shaped to form a membrane that achieves exceptional separation and permeability of nitrogen relative to methane compared to other polymer and zeolite membranes tested to date under actual operating conditions. This process leads to reductions in methane purification costs of more than 70% compared to the cryogenic processes commonly used in the industry.
Applicable to the selective capture of other contaminants such as carbon dioxide, the design of this new membrane, which is the result of synergy between complementary disciplines (molecular modeling, materials development, membrane manufacturing, and performance testing), opens up new prospects on an industrial scale for the recovery of natural gas and biogas. And beyond that, it could well revolutionize the issue of gas purification, which represents major challenges in the field of energy and the environment (improving air quality, producing pure hydrogen, etc.).
