Quantitative Raman spectroscopic investigation of geo-fluids high-pressure phase equilibria: Part II. Accurate determination of CH4 solubility in water from 273 to 603 K and from 5 to 140 MPa and refining the parameters of the thermodynamic model

• CH4 solubility in water was measured systematically from 273 to 603 K and from 5 to 140 MPa.
• 239 solubility data were reported.
• Parameters of thermodynamic model of Duan and Mao for calculating CH4 solubility in water were refined.

sCH4 solubilities in water at temperatures from 273.15 to 603.15 K and pressures from 5 to 140 MPa were systematically determined using quantitative Raman spectroscopy, and 239 solubility data were reported. The solubility data obtained from 313.15 to 533.15 K are generally consistent with previous experimental and thermodynamic studies. However, predictions of the Duan's model for temperatures below 313.15 K and above 533.15 K substantially deviate from the new measurements due to the previous lack of accurate experimental data in these P–T ranges. Parameters of the model were then refined, and the solubility data can now be accurately reproduced by the model with an AAD of 1.73%.