Product Optimization of Biphasic Absorbents for CO₂ Capture

New absorbents combining the advantages of phase separation and easily regenerated products were prepared with 2-methyl-2-amino-1-propanol (AMP) as the main absorbent and tertiary amines as the auxiliary absorbents and phase splitters. The absorption performances of absorbents containing different tertiary amines were systematically compared. Among these tertiary amines, N,N,N′,N′-tetramethyl-1,3-propanediamine (TMPDA) exhibited the most effective properties. For the absorbent TMPDA–AMP–H2O system (TAH), an absorption load of approximately 2.6 mol/kg was achieved. The kinetic and thermodynamic properties of TAH absorption were evaluated. It was found that the absorption products were readily decomposed into HCO3–, and the regeneration efficiency of TAH was above 91% at 358 K, while the regeneration energy consumption was only 2.0 GJ/t CO2. It should be noted that the addition of TMPDA effectively inhibited the precipitation of bicarbonate, thus leading to a higher absorption capacity and lower energy consumption per ton of CO2 loaded.