Synergistic effects of amino acids in clathrates hydrates: Gas capture and storage applications

This study reports enhanced carbon dioxide capture and storage, using gas hydrate-based technology, in the presence of low-dose (0.5 wt%) amino acids (AAs). The aqueous solutions, with l-methionine (l-met) and l-phenylalanine (l-phe), showed higher affinity in CH4 hydrate formation. However, the affinity for CO2 hydrates is high in l-met and very low in l-phe systems. Further, the hydrate conversion is high in the l-met solution in CO2+CH4 gas mixtures. However, it decreased dramatically in l-phe solutions, incredibly if the feed gas rich in CO2 (> 75 mol%). Higher hydrate conversion (~ 4–6 times) for CO2 and CO2+CH4 is observed upon using mixed AA aqueous solutions. Faster and efficient conversion is a consequence of the cooperative effects.