(356b) A Water-Immiscible Heavy Guest Molecule for Fast Methane Hydrate Formation

Clathrate hydrates have an ice-like appearance but a three dimensional structure having hydrogen bonded water cavities in which small guest molecules such as methane, hydrogen, carbon dioxide and light organic molecules are encaged. They can play an important role in CO₂ separation and also be a safe and economical medium for natural gas storage. But to apply gas hydrate techniques to industrial processes, we have to overcome the two barriers: (1) Gas hydrates are usually formed at the interface between the bulk gas and water phases. Once the solid hydrates cover the interface, gas hydrate formation decreases significantly because the hydrate layer becomes a barrier for mass transfer, and thus hydrate conversion is very low. (2) The gas hydrate formation kinetics is extremely unfavorable. This talk addresses the circumvention of the mass transfer and kinetic limits by introducing a water-immiscible heavy guest molecule of idomethane to enhance methane hydrate formation. We will demonstrate the key idea for maintaining liquid-liquid interfaces available for continuous methane gas access to the hydrate growth front and achievinga complete conversion to methane-idomethane binary hydrates within2 minutes in an unstirred reactor system.