Ethane (1) -Water (2) Solubility Modeling and New Water Content Measurements of Liquid Ethane in Equilibrium with Water and Hydrates

Ethane's susceptibility to hydrate formation during transportation and handling, particularly in LNG shipments, presents operational challenges in production facilities, pipelines and storage tanks. Accurate prediction of the minimum water content required for hydrate formation and precise hydrate dissociation points are essential for mitigating these issues. In this study, the sCPA-SRK, equation of state, coupled with van der Waals' classical mixing rules and van der Waals and Platteeuw's solid solution theory was used to determine the minimum water content required for hydrate formation (when within the hydrates' stability zone), over pressure and temperature ranges of 0.323-89.6 MPa and 201.65-413.15 K. The model achieved an absolute average deviation (AAD) of 9.25% when compared to measurements obtained from this study and the existing literature. Utilizing a novel method developed by Burgass et al. [1], 53 new water content measurements were obtained over the range of 273.15-293.15 K in liquid ethane which was in equilibrium with aqueous water or hydrates, achieving AAD of 4.61%. The model was also used to predict ethane solubility in the water aqueous phase within a pressure and temperature range of 0.101-100 MPa and 273.15-410.93 K, respectively, with a corresponding AAD of 6.5%, and was able to predict hydrate dissociation points successfully.

Automated summary

In this study, the minimum water content required for hydrate formation in ethane was determined using the sCPA-SRK equation of state, classical mixing rules, and solid solution theory. The model achieved an average deviation of 9.25% compared to measurements and literature data. A novel method was used to obtain new water content measurements in liquid ethane, with an average deviation of 4.61%. The model was also successful in predicting ethane solubility and hydrate dissociation points.