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.