Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Methanol can be an impurity in transported and stored anthropogenic CO2 in carbon dioxide capture and storage technology; likewise, methanol is one of the most useful CO2 modifiers for supercritical processes. Therefore reliable values of thermodynamic properties of CO2 rich mixtures CO2 + CH3OH are needed. We measured the following properties of a (CO2 + CH3OH) mixture with xCO2 1/4 0:9700 in dense phase at six temperatures from 263.15 K to 313.15 K: The speed of sound, c, up to 194.49 MPa, using a double-path pulse-echo method at 5 MHz, for which a repeatability study gave an overall standard uncertainty of c, u(c) = 5.9 10 4c. The density, q, at pressures 620.00 MPa using a vibrating-tube densimeter with a standard uncertainty, u(q) = 0.4 kg/m 3. Combining our c and q experimental values and the isobaric specific heat capacity, cp, from the GERG equation of state (EoS), we calculated q, cp, the volume-dependent solubility parameter, dV , and the Joule Thomson coefficient, lJT , at pressures 6195.0 MPa. We are the first to report the adaptation for compressed gases of a calculation method based on numerical integration previously used only for liquids. The experimental and calculated values were compared with those from the PC-SAFT and GERG EoSs, allowing us to validate both EoSs to represent the experimental properties of the system under most conditions studied and the calculation method up to 195.0 MPa.