A novel ternary amine blend for efficient post-combustion CO2 capture: experimental screening and energy assessment

Reducing regeneration energy remains a central challenge in post-combustion CO 2 capture by chemical absorption. In this work, nine aqueous MDEA/DMEA/PZ blends were systematically screened using thermodynamic performance indicators, including the heat of absorption, heat capacity, and equilibrium CO 2 absorption capacity. Two formulations, D30P10 (30% DMEA +10% PZ) and M5D25P10 (5% MDEA +25% DMEA +10% PZ), were identified as the most promising candidates for achieving low regeneration energy. These two solvents were further evaluated against two benchmarks, 30 wt% MEA and M30P10 (30% MDEA +10% PZ), in cyclic absorption–desorption experiments. Among them, M5D25P10 delivered the best overall balance of stable cyclic performance and a cyclic capacity about 0.55 mol CO 2 /mol amine. Benefiting from its high cyclic capacity and low heat of absorption, this solvent achieved a regeneration energy of 2.98 GJ/t CO 2 , which was 21.2% and 4.5% lower than those of 30 wt% MEA and M30P10, respectively. Kinetic performance indicators, including the initial absorption rate ( r abs ini ) and the overall mass transfer coefficient ( K G ), were also evaluated, and M5D25P10 exhibited the highest mass transfer coefficient among all tested solvents. These results collectively confirm that M5D25P10 is a highly promising solvent for post-combustion CO 2 capture. Moreover, a robust empirical correlation between r abs ini and K G was established for the first time, providing a rapid and solvent-efficient means of estimating mass-transfer performance.