CO₂ capture by methanol, ionic liquid, and their binary mixtures: Experiments, modeling, and process simulation

Abstract

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]

Predictive molecular thermodynamic models for ionic liquids

“…Lei et al 2 extended the original UNIFAC model proposed by Fredenslund et al 3 from conventional solvents to IL systems to further build the current UNIFAC models for ILs with the most complete parameters consisting of 75 main groups and 130 subgroups covering a wide pressure (0.01-500.0 bar) and temperature (243-453 K) range. [4][5][6] The UNIFAC model has been widely employed by researchers as valuable tools for predicting the activity coefficients of mixed systems with ILs or conventional solvents. 7,8 At present, The UNIFAC model has become one of the most widely applied thermodynamic models for quantitatively predicting thermodynamic properties, such as GLE, VLE, and LLE of the systems containing ILs.…”

Process Simulation and Optimization of Ammonia-Containing Gas Separation and Ammonia Recovery with Ionic Liquids

“…Process modeling, simulation, and optimization are crucial to design an industrial tail gas purification process. The process simulation can provide data support for the industrial application of the technology by analyzing the parameters of the system and discover the technical bottleneck in advance. − For example, Shiflett et al simulated a CO 2 capture process using pure [C 4 Mim]­[Ac], and the results suggested that 16% energy consumption could be saved compared with traditional processes. Liu et al studied shale gas CO 2 decarbonation process using [C 4 Mim]­[NTf 2 ], and the result indicated that the IL-based process can reduce over 42.8% of energy consumption.…”

Gas Solubility in Ionic Liquids: UNIFAC-IL Model Extension

“…It has been found that some ILs have very distinct solvation capacities for different gases, indicating the high potential of using ILs as solvents in gas separations . Meanwhile, work regarding the utilization of ILs as solvents in gas separation tasks from CO 2 capture to shale gas purification has been widely studied. − ,− …”