MEASUREMENTS OF MECHANICAL-PROPERTIES OF THE LIQUID CO2-WATER-CO2-HYDRATE SYSTEM

Microscopic observations of the liquid CO2-water-CO2-hydrate system we re conducted to measure both the interfacial tensions in these phases and the strength of the CO2-hydrate film. Measurements on hanging drop s revealed that the interfacial tension between liquid CO2 and water d ecreased slightly as the temperature was raised from 266.3 to 284.9 K, and that the average of the interfacial tension was about 29 dyn-cm(- 1). Contact angles between a water droplet and a teflon plate were mea sured before and after the thin film of CO2 hydrate was formed on the droplet. Comparisons of these contact angles indicated that the sums o f the interfacial tensions between liquid CO2 and CO2-hydrate film and between CO2-hydrate film and water were about 26% less than between l iquid CO2 and water. The destructive strength of CO2-hydrate film form ed on the pendant drop was examined by using a process for breaking of the film. Measurements indicated that the strength of the CO2-hydrate film depended on the film thickness. The film thickness of CO2 hydrat e was then estimated from the film strength.