(611d) The Design of Reversible Ionic Liquids for Post-Combustion CO2 Recovery
The post-combustion recovery of CO2 from existing coal fired power plants presents an immense separation challenge in terms of scale and difficulty. Presented here are silylamine-based reversible ionic liquids that have been developed to overcome the problems associated with today's best available technology for the capture of CO2 from power plant flue gas ? namely monoethanolamine (MEA). Over 600 coal fired power plants in the United States are currently producing the electricity to meet about 1/3 of the electricity demand for the nation. Regulations to limit the amount of CO2 released by these large point source emitters are imminent. In addition to the large number of existing facilities that release copious amounts of CO2, the flue gas streams themselves are technically challenging in terms of separating the CO2. Amine absorption represents today's best available technology for reducing the CO2 in power plant flue gas, but the process is costly due to the high energy requirement for regenerating the solvent. We are making modifications to the silyl amine-based reversible ionic liquid solvents in order to alter their physical and chemical properties favorably for application to CO2 recovery from power plant flue gas. We use FT-IR spectroscopy to determine physical and chemical absorption capacities. The information gathered is used to determine the thermodynamic properties (equilibrium constant, enthalpy and Gibb's free energy of reaction) for the reversible ionic liquid candidates for the purpose of developing a direct replacement for MEA-based absorption processes.