Abstract: The equilibrium curve for gas, liquid water/ice and hydrate is usually plotted as the pressure of hydrate-forming substance versus temperature. Equilibria in the region of gas hydrate stability are less frequently studied. In the present work, the equilibrium of gas hydrate, water vapor and hydrate-forming gas is described by means of thermodynamic modeling. For the hydrate – gas equilibrium, an equation expressing water vapor pressure over hydrate as a function of gas pressure and temperature has been obtained. This equation is true within the whole gas hydrate stability region. This equation was used to calculate the pressure of water vapor in equilibrium with methane and carbon dioxide hydrates at the constant pressure of hydrate-forming gas over a broad temperature range within the stability region. Calculation results are compared with the known results on measured water vapor concentrations in the gas phase which is in equilibrium with hydrate. With the help of this equation, an attempt is made to describe the processes of hydrate formation from water sorbed by mesoporous substances. At present, there are only few experimental data on water vapor concentrations in the gas phase in equilibrium with hydrate. The equation obtained by us can be the basis for theoretical calculations of water vapor pressure, the dew point of hydrate, and the boundary of hydrate formation from bound water.

Cite: Smirnov V.G. , Manakov A.Y.
Partial pressure of water vapor over gas hydrate
Journal of Molecular Liquids. 2026. V.458. 129807 :1-11. DOI: 10.1016/j.molliq.2026.129807 Scopus

Dates:

Submitted:	May 10, 2026
Accepted:	Jul 14, 2026
Published online:	Jul 17, 2026
Published print:	Aug 26, 2026

Identifiers:

≡ Scopus:

2-s2.0-105044833326

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