Determination of CO2 Solubility in Saturated Liquid CH4 + N2 and CH4 + C2H6 Mixtures above Atmospheric Pressure

Accurate CO 2 solubility data are crucial for putting a proposal of pressurized liquefied natural gas (PLNG) project into practice. A solid–liquid equilibrium (SLE) apparatus, which is based on the static–analytic method, has been set up to measure the solubility of carbon dioxide in saturated liquid CH 4 /CH 4 + N 2 /CH 4 + C 2 H 6 in the pressure region from atmospheric up to 3 MPa, corresponding to the temperature region from (112 to 170) K. In addition, Peng–Robinson (PR) and Suave–Redlich–Kwong (SRK) equations-of-state (EOS) are selected to calculate the solubility of carbon dioxide in CH 4 + N 2 and CH 4 + C 2 H 6 mixtures, and the results are consistent with the experimental data in the whole region. Two temperature-dependent correlations for the interaction coefficients k ij on CH 4 + CO 2 system are derived by the experimental data for PR and SRK EOS, which can improve the calculation accuracy of the binary and ternary solid–liquid phase equilibrium.