One of the MPI-team’s activities within the thematic ‘Environmental Sciences’ concerns the CO2 capture using ‘hydrate technology’. A unique set-up has been developed enabling in-situ assessment of clathrates technology’s performance parameters. Selectivity, CO2 recovery fraction, and recently normalized gas uptake can now be derived from the in-situ Raman spectroscopy analysis to probe hydrates properties. This breakthrough markedly differs from other set-ups currently used in hydrates research to characterize hydrates at macro-scale using absorption measurements and mass balance calculation. The originality lies here in the fact that our stand-alone optical spectroscopic technique provides high resolution signatures of guest molecules from which a self-consistent methodology was developed to reveal the relevant parameters of the hydrate system.

One of our main achievements was obtained on the separation of CO2-N2 gas mixtures using a quaternary ammonium salt (TBAB) as thermodynamic promoter, which allows a net reduction of the hydrate formation conditions from ~120 bar and 0°C in the pure water to ~35 bar and 15°C in the semi-clathrates. CO2 selectivity and capture were derived in these TBAB-based semi-clathrates. Best results in terms of selectivity were obtained using a slow-cooling protocol. Furthermore, the type A (tetragonal) structure observed in distinct protocols showed the best selectivity. These results can serve as a basis for developing the HBSP process for CO2 capture.