Gas hydrate phase equilibrium in methane + ethylene glycol, diethylene glycol, or triethylene glycol + water system

Abstract : In this communication, experimental hydrate dissociation pressures for the methane + diethylene glycol + water and methane + triethylene glycol + water systems are reported at 0.2, 0.35, and 0.5 mass fractions of glycol in aqueous solution in the temperature ranges of (265.0 to 283.2) K and (266.3 to 284.6) K, respectively. We also report experimental hydrate dissociation pressures for the methane + ethylene glycol (EG) + water system at a mass fraction of ethylene glycol of 0.65 in aqueous solution in the temperature range of (247.4 to 250.7) K. The experimental data were generated using an isochoric pressure-search method. The experimental hydrate dissociation data are compared with the corresponding literature data and also the literature data in the presence of pure water as well as the predictions of a thermodynamic model (HWHYD model). It is found that the experimental hydrate dissociation data reported in the literature for the aforementioned systems are rare. A discussion is made on the reliability of the literature data and also the predictions of the thermodynamic model.