Morphology Study of Methane Hydrate Formation and Dissociation in the Presence of Amino Acid

Abstract

Investigation of morphology of methane hydrate formation and dissociation in the presence of l-leucine amino acid was performed for the first time. Morphology changes observed during the nucleation, hydrate growth and dissociation of methane hydrates in the presence of varying concentrations of amino acid between 0.1 and 0.5 wt % are presented. In the presence of 0.3 wt % amino acid, a distinct methane bubble was observed to form after nucleation within the bulk solution that transfigured into methane hydrate during the hydrate growth phase. Hydrate crystals formed in the presence of amino acid are observed to be very flexible and expandable; this facilities the methane bubble to channel more gas inside and enlarge in the liquid solution. At higher concentrations of amino acid, greater than 0.3 wt %, mushy and indiscernible hydrate crystals were observed to drastically form in the bulk solution. We did not observe kinetic promotion at l-leucine amino acid concentrations below 0.3 wt %. Dissociation of methane hydrates in the presence of l-leucine amino acid was easy and complete in comparison to a voluminous frothy layer observed during the decomposition of methane hydrates in the presence of sodium dodecyl sulfate surfactant.