While CO2 capture with nonaqueous solutions is a promising
approach, regeneration of the solutions often requires high energy
consumption. This energy consumption can be potentially reduced by
microwave regeneration, the performance of which is strongly affected
by the selection of solvent. Therefore, we investigated the characteristics
of microwave regeneration for nine triethylenetetramine (TETA)
solutions. The results show that the heating rate of a solution in
the microwave was primarily affected by its viscosity, dielectric
constant, and heat capacity. The desorption energy consumption of
CO2-loaded solutions had a strong linear correlation with
the dielectric constant of the solvents over a certain solvent viscosity
range (1.4–88.8 mPa·s, 20 °C). A comparison of microwave
heating and conductive heating shows that the former performs better
when considering regeneration temperature, CO2 recovery,
and energy requirement. Under the condition of 800 W, the energy consumption
using microwave regeneration for 30 wt % TETA/BDO and TETA/PEG200
solutions decreased by 69% and 76%, while CO2 recovery
increased by 2.6 and 2.7 times, respectively, compared to a 30 wt
% monoethanolamine aqueous solution regenerated by conductive heating.
Therefore, TETA with microwave regeneration represents a promising
approach for CO2 capture and recovery.