Screening of conventional ionic liquids for carbon dioxide capture and separation

Screening of conventional ionic liquids for carbon dioxide capture and separation

Type	Journal Article
Author	Yingying Zhang
Author	Xiaoyan Ji
URL	http://www.sciencedirect.com/science/article/pii/S0306261915003633
Volume	162
Pages	1160-1170
Publication	Applied Energy
Date	January 15, 2016
Abstract	CO2 capture and storage can efficiently mitigate CO2 emissions, because CO2 capture is a crucial energy-intensive process. Ionic liquids (ILs) are potential liquid absorbents for CO2 separation. Researchers explore the CO2 absorption capacity and selectivity of ILs. While ILs have been screened for CO2 separation, only specific ILs have been examined in terms of energy consumption. Researchers collected 76 conventional ILs and screened them in terms of energy consumption to establish potential ILs for CO2 separation. Seventeen ILs were screened according to the CO2 dissolution enthalpy and CO2 working capacity criteria obtained from the Henry’s law constant in the preliminary screening. Seven ILs were then screened from the 17 ILs according to the CO2 working capacity from the measured CO2 solubility in the final screening. The energy consumptions of the seven screened ILs (i.e., [Emim][NTf2], [Bmim][BF4], [Bmim][PF6], [Bmim][NTf2], [Hmim][NTf2], [Bmpy][NTf2], and [Hmpy][NTf2]) were calculated, and the corresponding gas solubility selectivities were discussed. The energy consumptions and properties of the seven screened ILs were compared with those of the commercial CO2 absorbents of 30 wt% MEA, 30 wt% MDEA, and dimethyl ethers of polyethylene glycol (Selexol™ or Coastal AGR®). Results revealed that the energy consumptions of the seven screened ILs were lower than those of the commercial CO2 absorbents. [Hmpy][NTf2] showed the lowest energy consumption among the seven screened ILs under the operating conditions set.