Experimental measurement and thermodynamic modeling of water content in methane and ethane systems

In this article, we first report a summary of experimental methods used for measuring water content and water dew point of gaseous systems. After reviewing the available water content data in the literature, new experimental data and thermodynamic modeling on the amount of water in methane and ethane systems are reported. Equilibrium measurements are conducted at 282.98-313.12 K and 282.93-293.10 K and pressures up to 2.846 and 2.99 MPa, respectively. A static-analytic apparatus has been used in the experimental measurements, taking advantage of a pneumatic capillary sampler in combination with an exponential dilutor. The Valderrama modification of Patel-Teja equation of state with the nondensity dependent mixing rules are used for modeling the fluid phases with the previously reported binary interaction parameters. The hydrate phase is modeled by the solid solution theory of van der Waals and Platteeuw, using the previously reported Kihara potential parameters. The fugacity of ice is calculated by correcting the saturation fugacity of water at the same temperature by using the Poynting correction. The experimental data generated in this work were compared with predictions of the thermodynamic model as well as other predictive methods. The predictions were in good agreement with the experimental data, demonstrating the reliability of experimental techniques and thermodynamic modeling used in this work.