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

“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:


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


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.”

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