Phase Diagrams of the Ternary Gas Hydrate Forming Systems at High Pressures. Part 1. Propane–Methane–Water System

Cross sections of the ternary system propane–methane–water at pressure up to 15 kbar have been investigated by means of differential thermal analysis. It is stated that a double gas hydrate of the cubic structure II is formed in the system. It is stable within the whole pressure range investigated. It is most likely that at pressures above 3.4 kbar one more double hydrate exists in the system. The possibility of the formation of solid solutions of methane in propane hydrates and of propane in methane hydrates existing under different P–T conditions is discussed on the basis of P–T curves corresponding to monovariant equilibria in the system.