Low-energy phase-change absorbents for efficient onboard CO₂ capture in the maritime sector

The International Maritime Organization (IMO) has introduced new regulations aimed at reducing carbon emissions in the shipping industry. In this study, seven amines were combined with seven phase separation agents to screen three phase-change absorbents that demonstrated distinct phase separation following CO₂ absorption: DETA + n-Butanol + H₂O, DETA + NMP + H₂O, and DETA + DMSO + H₂O. Among these, the DETA + DMSO + H₂O phase-change absorbent outperformed the MEA-based absorbent in both CO₂ absorption capacity (3.17 mol CO₂/kg solvent) and desorption capacity (2.13 mol CO₂/kg solvent), corresponding to improvements of 46% and 12%, respectively. Furthermore, its regeneration energy consumption was only 29% that of MEA. These results demonstrate that the DETA + DMSO + H₂O absorbent offers efficient CO₂ capture performance alongside significant energy-saving potential, making it a promising candidate for onboard carbon capture applications.