Keywords: CO2 capture, flue gas, ionic liquids, natural gas
Feasibility of using ionic liquids for carbon dioxide capture
Ionic liquids (ILs) are organic salts that are liquids in their pure state at ambient conditions. They are frequently referred to as 'environmentally benign' due to their immeasurably low vapour pressure. In addition to their more widely studied capabilities as solvents for reactions, several ionic liquids also show potential in other environmentally conscious applications, such as in the capture of CO2. In previous gas solubility studies with the ionic liquids 1-n-butyl-3-methylimidazolium hexafluorophosphate, [bmim][PF6], and 1-n-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4] [1,2], we have found that CO2 has a much higher solubility in these ILs than many other gases, including N2, O2, and CH4. Here we show experimental measurements using a static absorber that confirm that [bmim][PF6] can be used to remove CO2 from a gas mixture containing either N2 or CH4. We also compare capture of CO2 using ILs to conventional technology using monoethanolamine (MEA).