Brief discussion of the influence of CO2 partial pressure using water-lean solvents

https://doi.org/10.1016/j.seppur.2020.118193

“From their inception, water-lean solvents are mixtures of amines with organic solvents that have higher CO₂ physical solubility than water. Therefore, there are two important aspects to keep in mind when analyzing their vapor–liquid equilibrium (VLE) data:

a.

At low CO₂ partial pressures, CO₂ is absorbed mostly through chemical reaction.

b.

At high CO₂ partial pressures, CO₂ is absorbed mostly through physical solubilization.

If one plots the VLE data of a water-lean solvent against that of its aqueous counterpart (i.e. an aqueous solvent with same amine concentration), it is often possible to identify a point in which both datasets cross. We have nicknamed this the cross-over point following the example of Macgregor and Mather [60]. This point loosely divides the VLE curves of water-lean solvents into two distinct areas, which we shall discuss separately.”