The CO 2 solubility data in the ionic liquid (IL) 1-allyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide, methanol (MeOH), and their mixture with different combinations at temperatures of 313.2, 333.2, and 353.2 K and pressures up to 6.50 MPa were measured experimentally. New group binary interaction parameters of the predictive universal quasichemical functional-group activity coefficient (UNIFAC)-Lei model, which has been continually advanced by our group, were introduced by correlating the experimental data of this work and the literature. The consistency between experimental data and predicted results proves the reliability of UNIFAC-Lei model for CO 2 -IL-organic solvent systems. The newly obtained parameters were incorporated into the UNIFAC property model of Aspen Plus software to optimize a conceptual process developed for the purification of a CO 2 -containing gas stream. The simulation results indicate that the use of IL either mixed with MeOH or purely considerably lowers the process power consumption and improves the process performance in terms of CO 2 capture rate and solvent loss. ðx 1 Þ n 5Fðm 1 ; m 2 ; m 3 ; m 4 ; m 5 Þ (1) Figure 2. Flow sheet of the CO 2 capture processes developed in this work.Lines, predicted results by the UNIFAC-Lei model; scattered points, experimental data. ( ) pure [AMIM] 1 [Tf 2 N] 2 ; ( ) 80 wt % [AMIM] 1 [Tf 2 N] 2 1 20 wt % MeOH; ( ) 50 wt % [AMIM] 1 [Tf 2 N] 2 1 50 wt % MeOH; ( ) 20 wt % [AMIM] 1 [Tf 2 N] 2 1 80 wt % MeOH; ( ) pure MeOH. [Color figure can be viewed at wileyonlinelibrary.com]

In this work, a priori COSMO-SAC model was combined with the original UNIFAC model, and thus the new COSMO-SAC-UNIFAC thermodynamic model with a strong predictive power for fluid phase equilibrium (VLE, LLE) was proposed. By this means the group binary parameter matrix of original UNIFAC model was extended by introducing the new 648 vacant parameter pairs for 51 main functional groups for the conventional substances in this work. Moreover, the combined thermodynamic model was first applied to process simulation on gas drying with ionic liquids (ILs). To verify the reliability of the COSMO-SAC-UNIFAC model, the predictive values were directly compared with experimental data coming from this work, our previous work, and literature. The moderately accurate predictions of the COSMO-SAC-UNIFAC model demonstrate the high potential applicability of this new model, especially for numerous systems with missing parameters including ILs, which are normally encountered in the original UNIFAC model.

No abstract

Ionic liquids (ILs) as a new class of gas dehydration solvents, in combination with the traditional triethylene glycol (TEG) solvent, were first proposed for carbon dioxide (CO 2 ) dehydration. Among 210 preliminary ILs, the hydrophilic [BMIM] + [BF 4 ] − was selected based on the COSMO-RS model-involved IL screening methodology. The solubilities of CO 2 in pure TEG, pure [BMIM] + [BF 4 ] − , binary mixture of TEG + [BMIM] + [BF 4 ] − , and ternary mixture of TEG + [BMIM] + [BF 4 ] − + H 2 O were measured experimentally. Two new binary interaction parameters were introduced by correlating a series of experimental data with the UNIFAC-Lei model.The COSMO-RS model along with the reduced density gradient method was applied to interpret the nature of interaction between molecules. The CO 2 dehydration experiment was conducted in a laboratory-scale absorption tower. The process simulation indicates that, in comparison with pure TEG, the use of IL purely or mixed with TEG improves both separation performance and process energy penalty.

For the first time, a practical ionic liquid (IL) based acid gas removal (AGR) process for selective removal of CO2 and H2S from syngas was designed, simulated, and optimized in this work. The popular UNIFAC property model, the parameters of which derived from experimental data, was used in the simulation. The newly developed process, named IL-Emitsol, utilizes the [EMIM]­[Tf2N] solvent and yields three product streams as (1) a clean syngas with 0.27 mol % CO2 and less than 100 ppb H2S, (2) a CO2 stream with 96.68% CO2 capture level (CO2CL) and 99.37 mol % purity with less than 100 ppm H2S, and (3) a H2S stream containing 63.66 mol % H2S. In comparison with the benchmark Rectisol process, the IL-Emitsol process is more efficient in terms of clean syngas production, CO2 capture and production, H2S production, solvent loss, and electricity consumption. However, it requires more than 4 times higher direct capital investment, although it is indeed a typical chemical process intensification technology.