Measurement of the Water Solubility in the Gas Phase of the Ethane + Water Binary System near Hydrate Forming Conditions

This project involves measurements of the vapor phase composition for the ethane + water binary system presenting phase equilibria near hydrate-forming conditions. The H 2 O + C 2 H 6 binary system isothermal vapor phase data, concerning both vapor−liquid and vapor−hydrate equilibria, were measured at (278.08, 283.11, 288.11, 293.11, 298.11, and 303.11) K and pressures up to the ethane vapor pressure. In this work a static−analytic apparatus, taking advantage of a pneumatic capillary sampler (Rolsi, Armines' patent) developed in the Cenerg/TEP laboratory, is combined with an exponential dilutor for calibration purposes and a PVT apparatus to visualize and determine the hydrate-forming conditions. The six sets of isothermal P, y data are represented with the Peng−Robinson equation of state (PR-EoS) using the Mathias−Copeman α function and the Huron−Vidal mixing rules involving the NRTL local composition model (PR-EoS/MC-HV-NRTL). This equation (PR-EoS/MC-HV-NRTL) is also used to fit the available literature data. A Henry's law approach was selected to treat the aqueous phase.