Metal–Organic Frameworks for Helium Recovery from Natural Gas via N2/He Separation: A Computational Screening

About 500 metal–organic frameworks (MOFs) were subject to in silico screening for helium separation from natural gas. The equimolar mixture of helium and nitrogen was selected based on the available technical data for operating units. Geometry-based structural analysis followed by grand canonical Monte Carlo simulations was used to study several parameters including the effect of helium dilution in the gas mixture and electrostatic interactions in target gas uptake. We established structure–property relationships among various factors including adsorbent performance indicator (API) to rank MOFs based on their performance which also brought us valuable knowledge on the desired ranges of helium void fraction, accessible surface area, and pore diameter. We have identified top 10 performing MOFs for adsorption-based separation which have been consequently studied in more detail to obtain deeper insight on the possible adsorption sites and adsorptive behavior. We also assessed the diffusion-based separation to...