(356e) Measurements and Modeling of Gas Hydrate Formation from High Salinity Systems

In this study, measurements and modeling of gas hydrate phase equilibrium have been performed for aqueous solutions with high salt concentration (near-saturated and saturated solutions) to comprehensively study the interplay of hydrate formation and salt precipitation. As no data exist for hydrate phase equilibria, including the triple point for CH₄ [g] â?? Solution [l] â?? Hydrate [s] and quadruple one for CH₄ [g] â?? NaCl [s] â?? Solution [l] â?? Hydrate [s], measurements have been performed with undersaturated and saturated solutions of NaCl, CaCl₂, KCl, and MgCl₂, as single salts and mixtures, using an isochoric method for pressures up to 206 MPa. For the modeling part, we have developed a simple correlation to determine the hydrate suppression temperature as a function of the salt concentration. This correlation can predict the hydrate equilibrium conditions to within about 1 ^oC. Moreover, the approach used for the correlation can be readily extended to other salt systems.