posted on 2016-06-13, 00:00authored byFrancesco Barzagli, Fabrizio Mani, Maurizio Peruzzini
The neat secondary
amines 2-(methylamino)ethanol, 2-(ethylamino)ethanol,
2-(isopropylamino)ethanol, 2-(benzylamino)ethanol and 2-(butylamino)ethanol
react with CO2 at 50–60 °C and room pressure
yielding liquid carbonated species without their dilution with any
additional solvent. These single-component absorbents have the theoretical
CO2 capture capacity of 0.50 (mol CO2/mol amine)
due to the formation of the corresponding amine carbamates and protonated
amines that were identified by the 13C NMR analysis. These
single-component absorbents were used for CO2 capture (15%
and 40% v/v in air) in two series of different procedures: (1) batch
experiments aimed at investigating the efficiency and the rate of
CO2 capture; (2) continuous cycles of absorption–desorption
carried out in packed columns with absorption temperatures brought
at 50–60 °C and desorption temperatures at 100–120
°C at room pressure. A number of different amines and experimental
setups gave CO2 capture efficiency greater than 90%. For
comparison purposes, 30 wt % aqueous MEA was used for CO2 capture under the same operational conditions described for the
solvent-free amines. The potential advantages of solvent-free alkanolamines
over aqueous MEA in the CO2 capture process were discussed.