Hydrodynamic modeling of ionic liquids and conventional amine solvents in bubble column

Abstract

The green solvent ionic liquids (ILs) are getting attention in variety of industries, because of their unique properties. Few studies explain the hydrodynamics of ILs, but the comparison with conventional amine solvents in CO2 capture process has not so far been reported. The primary target of this research is to develop a state of the art computational fluid dynamics (CFD) model that would be useful to understate hydrodynamic parameters of both ILs and conventional amine solvents in a glance. In present study, three ILs are investigated inside a 3D flat bubble column and their higher viscosities are examined vigilantly by comparison with three amine solvents. The flow pattern, liquid velocity magnitude, CO2 holdup and bubble size distribution are explained. It is reported that current CFD model may be used for higher viscous ILs and amine solvents. Compared with amine solvents, CO2 plume meandering behavior was not observed and very low gas holdup was obtain in ILs. The velocity magnitude of ILs increased with the height in bubble column, but a decreasing trend with column height was followed in the case of amine solvents. CO2 exhibited non-coalescence behavior in ILs, but coalescence and breakup phenomena were seen in amine solvents. Finally, baffled type industrial tray column is also investigated and some useful hydrodynamic aspects in the comparison of pure ionic liquid, 90%-solution of ionic liquid and 30%-solution of MEA are drawn. The experimentally validated CFD model would be useful for switching to ILs from corrosive amine solvents and further investigation of new economical ILs.