Vapor-liquid-liquid equilibrium measurements and modeling of the methanethiol + methane + water ternary system at 304, 334, and 364 k

Abstract : New vapor-liquid-liquid equilibrium (VLLE) data for methanethiol (CH 3SH) + methane (CH 4) + water (H 2O) have been obtained at three temperatures (304, 334, and 364 K) and pressures up to 9 MPa. A "static-analytical" method was used to perform all of the measurements. The objective was to provide experimental VLLE data for CH 3SH with other natural gas contents at its crude form for which limited or no data are available in the open literature. Such kinds of data are required for the industrial modeling of sulfur emissions. It is observed from the experimental data that the solubility of CH 4 in the aqueous and organic phases increases with an increase of the total system pressure and decreases with an increase of the temperature. However, the solubility of CH 3SH in the aqueous and organic phases decreases slightly with an increase of the total system pressure and increases significantly with an increase of the temperature. The new VLLE data of this ternary system were compared with predictions of the cubic-plus-association equation of state. The model tends to underpredict the concentration of CH 3SH in all phases, particularly the vapor phase.