Evaluation of the Potential of Natural Gas Sweetening by Using Imidazolium Ionic Liquid [bmim][NTf2] based on PC-SAFT Equation of State

In the present study, for the first time, the potential of gas sweetening of iranian gas composition by using an imidazolium- based ionic liquid solvent called 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim] [ntf2] has been evaluated. the results are compared with natural gas sweetening using an amine-based solvent. the pc-saft equation of state was used as a thermodynamic model in aspen plus software version 10. since the thermophysical properties of the ionic liquid are not available in the software, and these properties for pure and multicomponent systems are in vital demand, all the necessary properties are correlated to pc-saft eos as well as related thermophysical properties. the gas sweetening process is simulated for both ionic liquid and amine-based solvents, and the results are compared. the results show that to meet the sweet gas pipeline specification (4 ppm h2s and 2% co2), the energy consumption of the ionic liquid-based process is much higher than that of the mdea-based solvent. this result indicates that ionic-based solvents ([bmim][ntf2]) are not suitable for gas sweetening due to their lack of desirable properties, including low vapor pressure, high thermal stability, high solubility, and tunability.