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Water-lean solvents are typicallydefined as mixtures between anorganic diluent and an amine. These solvents are thought to deliverpotential benefits in CO2 capture systems, such as enhancedmass transfer properties, increased absorption capacities, and lowerregeneration heat duties. However, it is yet unclear what propertiesof the organic diluent one should aim for when developing these solvents.For example, while it is understood that high CO2 physicalsolubility is desirable if one wants to enhance mass transfer rates,the contributions of viscosity and electrostatic properties （e.g.,dielectric permittivity） are still uncertain. Simultaneously, as lowvapor pressures are interesting for reducing latent heat duties inthe regeneration process, the effects of viscosity and thermal conductivityin the cross-heat exchanger before the reboiler are often neglectedor underestimated. This work aims to address such drawbacks by carryingout an explicit analysis, based on rigorous modeling, on the influencesof each individual parameter of the organic solvent when mixed withmonoethanolamine as a token amine. The contributions of CO2 solubility, viscosity, dielectric permittivity, heat capacity, thermalconductivity, and vapor pressure to the performances in the absorberand the desorber are exhaustively discussed. Finally, an overall assessmenton which properties are effectively desirable in a water-lean solventis performed, as well as some predictions on which kinds of challengesthese solvents will have to face upon implementation.
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