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High-Pressure Vapor-Liquid Equilibrium Measurements of Methane + Water Mixtures by Nuclear Magnetic Resonance Spectroscopy



Samantha Miller, Chris Suiter, Mark O. McLinden, Jason A. Widegren, Nancy Levinger, Bret Windom, Michael Sartini


Accurate vapor-liquid equilibrium (VLE) data are required to predict the condensation of low-volatility components in natural gas pipelines. Here we apply 1H nuclear magnetic resonance (NMR) spectroscopy to measure the VLE of methane + water mixtures at temperatures of 299.73, 307.98, and 323.25 K, and pressures ranging from 0.69 MPa to 13.89 MPa. Experiments were carried out with a 600 MHz spectrometer. The samples were prepared and equilibrated in a high-pressure zirconia sample tube. Liquid-phase and vapor-phase compositions were measured in separate experiments by adjusting the height of the liquid phase in the sample tube. For the liquid-phase samples, equilibration was hastened by adding glass beads to the sample and repeatedly inverting the sample tube. Our VLE results are compared with literature data and models. NMR measurements of the liquid-phase methane concentration are in good agreement literature data and with Henry's Law predictions at low pressures; however, large deviations are seen with the commonly used GERG-2008 model for natural gas systems. NMR measurements of the vapor-phase water concentration are systematically lower than literature data and models.
Journal of Natural Gas Science and Engineering


Vapor-liquid equilibrium (VLE), mixture of methane and water, nuclear magnetic resonance (NMR) spectroscopy, high-pressure zirconia sample tube, REFPROP, thermodynamic calculation, GERG-2008 natural gas model, integration of NMR spectra, peak overlap correction.


Miller, S. , Suiter, C. , McLinden, M. , Widegren, J. , Levinger, N. , Windom, B. and Sartini, M. (2023), High-Pressure Vapor-Liquid Equilibrium Measurements of Methane + Water Mixtures by Nuclear Magnetic Resonance Spectroscopy, Journal of Natural Gas Science and Engineering, [online],, (Accessed June 14, 2024)


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Created October 31, 2023, Updated January 4, 2024