Experimental Measurement and Thermodynamic Modeling of Water Content in Methane and Ethane Systems

Abstract

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.

Calculation of vapor–liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part III. Extension to water–light hydrocarbons systems

“…This model agrees well with the data of Dhima et al (1998), and the data of Anthony and McKetta (1967a) except one anomalous data point. Some data of Wang et al (2003) deviate from the data of Mohammadi et al (2004b) by 10-20% whereas the data of Mohammadi et al (2004b) at temperatures above 300 K deviate from the data of by 10-50%. The calculations of this model agree with the data of Mohammadi et al (2004b) at temperatures below 300 K. Danneil et al (1967) measured the mutual solubilities of ethane and water in a wide P-T range (from 473 to 673 K, and from 200 to 3700 bar).…”

“…4 displays that the consistency of the calculation of this model with the extensive measurements of , and . Anthony and McKetta (1967a), Dhima et al (1998), Wang et al (2003) and Mohammadi et al (2004b) also reported ethane solubility data at elevated pressures. This model agrees well with the data of Dhima et al (1998), and the data of Anthony and McKetta (1967a) except one anomalous data point.…”

Mutual solubilities of hydrocarbons and water with the CPA EoS

“…For light n-alkanes, from methane to butane, an extensive experimental database for the mutual solubilities of these systems is available in a large range of temperature (298.15-573.15 K) and pressure (0.1-200 MPa) [41][42][43][44][45][46][47][48][49][50][51][52][53][54]. To provide a good description of these experimental data, for each system a single, temperature independent, binary interaction parameter was required.…”

Thermodynamic consistency test for experimental data of water content of methane

“…It was shown in previous works 4,9,15 that the ADs% of the model results used in this work are \20% for all the experimental data points. Therefore, the model is acceptable for this purpose.…”

“…In other word, the nonideality of the gas phase is the critical factor determining water content in the intermediate pressure range. 4,12,15,16 To estimate vapor pressure and molar volume of water in Eq. 14, the relations reported by Daubert Ice-gas equilibrium normally reaches at low-intermediate pressures and therefore Eq.…”