Characteristics of the Stability and Decomposition of Metastable Gas Hydrates

Results are presented from studying the metastable states of Freon-12 gas hydrate via pulsed NMR in the range of thermodynamic parameters limited by the line of ice–hydrate–gas and supercooled water–hydrate–gas equilibrium in the P–T phase diagram. The dependence is found for the lifetime of metastable Freon-12 gas hydrate on a sample’s temperature and degree of hydrate formation. New data on the conditions of the stability and decomposition of the metastable states of the given gas hydrate are obtained using samples with 100% conversion of water to the former. It is found that the crystallization of water formed upon the dissociation of Freon-12 gas hydrate into supercooled water and gas alters the mechanism of dissociation. A scheme for the formation of water/ice upon the dissociation of gas hydrates is proposed to explain the experimental data.