| Selectivity of CO2 over ethane in four [Tf2N] and three [FSI] based ionic liquids of importance in the sweetening of natural gas Devjyoti Nath1; Ali Tajouri1; Amr Henni2; 1UNIVERSITY OF REGINA, REGINA, Canada; 2UNIVERSITY OF REGINA, Regina, Canada; PAPER: 59/Molten/Regular (Oral) SCHEDULED: 11:55/Wed. 30 Nov. 2022/Game ABSTRACT: <p>Anthropogenic emission of carbon dioxide (CO2) is accelerating global warming. One of the technologically advanced techniques for mitigating CO2 emission is to capture CO2 from the major point of sources such as flue-gas and store in geological storage. Apart from the storage in geological formation, captured CO2 can also be used in enhanced oil recovery. Furthermore, CO2 capture process is also used for natural gas sweetening to maintain the quality of natural gas. CO2 capture with the alkanolamine based chemical solvents is the most efficient technique that has been used for long-time, but this technique is still not economical due to high regeneration cost, high amount of solvent degradation and high corrosiveness. Ionic liquids (ILs) which are molten salt with a melting point below 373.15 K [1] have received enormous research emphasis recently as an alternative to reactive solvents as they require much less energy for regeneration and they possess special physical properties such as non-flammable, negligible vapor pressure, high stability, etc.<br />Previous study showed that the anion part of the ILs has more significant effect on the solubility of gases in ILs and the cation has a minor effect [2]. Moreover, the presence of S=O groups and fluorination in anion increase solubility of CO2 in ILs [3]. Due to the presence of S=O groups and fluorination in bis(trifluoromethylsulfonyl)imide ([Tf2N]) and bis(fluorosulfonyl)imide ([FSI]) anion, four [Tf2N] based ILs and three [FSI] based ILs were selected for this study. The major objectives of this study were to investigate the solubility of carbon dioxide (CO2) and ethane (C2H6) in [Tf2N] and [FSI] anion based ILs, estimate the selectivity towards CO2 over C2H6 for these ILs and compare the solubility of CO2 and selectivity among these ILs.<br />Solubility of CO2 and C2H6 in [Tf2N] and [FSI] ionic liquids, {N,N-dimethyl-N-ethyl-N-(3-methoxy-propyl)ammonium bis(trifluoromethylsulfonyl)imide, 1-Allyl-3H-imidazolium bis(trifluoromethyl sulfonyl)imide, 1-(3-Hydroxy propyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, N,N-diethyl-N-methyl-n-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide, 1-Methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, N-propyl- n-methylpyrrolidinium bis(fluorosulfonyl)imide, and N,n-diethyl-n-methyl-n-propylammonium bis(fluorosulfonyl)imide} were measured at (303.15, 323.15, and 343.15) K and at pressures up to 1.5 MPa with a gravimetric microbalance. Solubility of CO2 and C2H6 in these ILs increased significantly with the increase in pressure in a linear manner and reduced with an increase in temperature. Henry's law constants, enthalpies and entropies for the absorption of CO2 and C2H6 were estimated from the solubility data. Experimental solubility data were correlated with the Peng-Robinson (PR) equation of state. The selectivities towards carbon dioxide (CO2) over C2H6 for these ILs were also estimated. Results showed that [Tf2N] based ILs exhibited higher CO2 solubility compared to [FSI] based ILs, while [FSI] based ILs exhibited higher selectivity towards CO2.</p> References: <p>REFERENCES:<br />[1] Turnaoglu, T., Minnick, D. L., Morais, A. R. C., Baek, D. L., Fox, R. V., Scurto, A. M., & Shiflett, M. B. (2019). Journal of Chemical & Engineering Data, 64(11), 4668-4678.<br />[2] Anthony, J. L., Anderson, J. L., Maginn, E. J., & Brennecke, J. F. (2005). The Journal of Physical Chemistry B, 109(13), 6366-6374.<br />[3] Muldoon, M. J., Aki, S. N., Anderson, J. L., Dixon, J. K., & Brennecke, J. F. (2007). The Journal of Physical Chemistry B, 111(30), 9001-9009.</p> |
