An experimental investigation of the phase equilibrium of the binary system (methane plus water) at low temperatures: Solubility of methane in water and three-phase (vapour plus liquid plus hydrate) equilibrium

New experimental results are presented for the solubility of methane in water at constant temperatures of 283 K and 298 K and pressures up to 10 MPa, and for the pressure-temperature coordinates of the three-phase (vapour +liquid + hydrate) equilibrium (when the liquid mainly consists of water) at temperatures between 274K and 285 K. The new experimental results are compared with literature data. The gas solubility data are used to determine Henry's constant and the partial molar volume of methane in water. Two thermodynamic models are used to describe the gas solubility. One model neglects the amount of water in the vapour whereas the other model describes the vapour as a binary mixture of (methane + water) and allows to predict the small fraction of water in the vapour phase. The prediction results are also compared with literature data. (C) 2015 Elsevier B.V. All rights reserved.