CO₂ Capture Performance of the DEGDEE-AEEA-AMP Ternary Phase-Change Absorbent

To address the issues of poor regeneration performance and high regeneration energy consumption associated with traditional CO2 absorbents, the development of novel phase-change absorbents has become a key area of research. In this study, a new phase-change absorbent system, DEGDEE-AEEA-AMP, is developed, using N-(2-hydroxyethyl)ethylenediamine (AEEA) as the main absorbent, bis(2-ethoxyethyl)ether (DEGDEE) as the phase-separation agent, 2-amino-2-methyl-1-propanol (AMP) as the activator, and water as the solvent. The performance of this system is compared with that of monoethanolamine (MEA) at a 30% mass concentration, which serves as the reference standard. The study includes absorption, desorption, corrosion, cyclic absorption–desorption experiments, and regeneration energy consumption estimations. The results indicate that the volume of the rich phase in the DEGDEE-AEEA-AMP (DAP) system constitutes 56.7% of the total volume. When the AMP mass fraction is 15%, the absorption capacity reaches 2.52 mol·kg–1, which is 14.0% higher than that of MEA. The maximum desorption rate is 13.19 × 10–3 mol·kg–1·s–1, which is 3.39 times higher than that of MEA. The minimum regeneration energy consumption is 2.742 GJ·t–1 CO2, representing a 29.9% reduction compared to 30% MEA. The corrosion rate of the rich liquid is 0.230 mm/a, 1.32 times that of MEA, but it can be significantly reduced by adding anhydrous Na2SO3. When the AMP mass fraction is 15%, the DAP phase-change absorbent system exhibits high absorption and desorption performance, good cyclic stability, and lower regeneration energy consumption.