(70h) Use of Reversible Ionic Liquids as Solvents for Post-Combustion Recovery of CO2 From Coal-Fired Power Plants

Authors: 
Hart, R., Georgia Institute of Technology
Flack, K., Georgia Institute of Technology
Sivaswamy, S., Georgia Institute of Technology
Switzer, J., Georgia Institute of Technology
Biddinger, E. J., Georgia Institute of Technology
Talreja, M., Georgia Institute of Technology
Pollet, P., Georgia Institute of Technology, Specialty Separations Center
Liotta, C. L., Georgia Institute of Technology
Eckert, C., Georgia Institute of Technology
Rohan, A., Georgia Institute of Technology


CO2 emissions are likely to be regulated in the near future, so we need to develop energy and cost efficient strategies for CO2 capture. Coal-fired power plants, essential for electricity generation, are one of the largest emitters of CO2.  Our unique reversible ionic liquids (RevILs) take advantage of a dual chemical and physical absorption capture mechanism. Unlike traditional ionic liquids, these silylamine-based solvents react with CO2, forming an ionic liquid that may further capture CO2 through a physical absorption process. Through thermal reversion, the CO2-swollen ionic liquids return to their molecular components, releasing chemically and physically absorbed CO2.  The precursors thus recovered are then recycled for additional capture.  Reversible ionic liquids can effectively capture CO2 without the requirement of large quantities of a co-solvent such as water, contrasting with the current monoethanolamine (MEA) technology used for CO2 capture. This allows for significant energy savings during the regeneration step.  

We leverage an extensive understanding of structure-property relationships, and present the optimization of RevIL-based systems for CO2 capture through viscosity, heats of generation and physical capacity. Further, we discuss the use of a unique in-situ technique to measure physical absorption, and hence values for Henry’s Law constants, as a guide for identifying molecules with optimal capture properties.