Thermodynamic Modeling and Assessment of Ionic Liquid-Based CO2 Capture Processes

Ionic liquid (IL)-amine hybrid solvents have been experimentally proved to be effective for CO2 capture. This Article provided rigorous thermodynamic models, process simulation, and cost estimation of a potential design of IL-based CO2 capture processes. Three lLs ([Bmim][BF4], [Bmim][DCA], and [Bpy][BF4]) were investigated to blend with MEA aqueous solution. The physicochemical properties of the ILs were predicted by several temperature-dependent correlations. Phase equilibria were modeled based on Henry's law and NRTL equation, and the calculated values were in good agreement with the experimental data. The simulation results show that the [Bpy][BF4]-MEA process can save about 15% regeneration heat duty as compared to the conventional MEA process, which is attributed to the reduction of sensible and latent heat. Moreover, a modified [Bpy][BF4]-MEA process via adding intercooling and lean vapor recompression presents 12% and 13.5% reduction in overall equivalent energy penalty and capture cost as compared to the conventional MEA process, respectively.