Abstract
This paper reports a visual crystal growth study concerning the separation of carbon dioxide utilizing formation and dissociation of clathrate hydrate. The high equilibrium pressure of CO_2 hydrate may be moderated with the addition of a second guest substance such as tetra-n-butylammonium bromide (TBAB). Visual observations were carried out on the formation and growth of semiclathrate hydrate crystals in the system of CO_2 + TBAB + water. The hydrate crystals first formed in the bulk of the aqueous liquid as well as at the ga/liquid interface. Both of the hydrate crystals then grew into the aqueous liquid. The morphology of hydrate crystals grown in aqueous liquid varied distinctly depending on the system subcooling ΔT_sub.
