Comparative life cycle assessment and process simulation of AEEA and MEA solvents for sustainable CO₂ capture in cement manufacturing

This study integrates process modeling and life cycle assessment (LCA) to evaluate the operational and environmental performance of aminoethyl ethanolamine (AEEA) in comparison with the benchmark solvent monoethanolamine (MEA) for post-combustion CO₂ capture in cement plants. Process simulations conducted in Aspen Plus at 90% CO₂ capture and a lean loading of 0.20 mol CO₂/mol amine show that AEEA reaches a higher rich loading (0.77 mol CO₂/mol amine) than MEA (0.46 mol CO₂/mol amine), reducing solvent circulation by 22%. AEEA also requires 12% less regeneration heat (3.01 vs. 3.42 GJ/t CO₂), while electricity demand, which is dominated by CO₂ compression, is nearly identical for the two solvents. The simulation results were integrated with solvent production inventories within an LCA framework following ISO 14040 and ISO 14044 standards, using SimaPro software and the Ecoinvent database. Environmental impacts were evaluated across climate change, human health, ecosystem quality, and resource depletion categories. The production-stage assessment indicates that AEEA has a higher environmental burden per unit mass than MEA. However, when the solvents are evaluated within the CO₂ capture process, AEEA benefits from its higher CO₂-loading capacity and lower regeneration-energy requirement, which reduce operational energy demand. This difference is primarily attributed to the more energy-intensive synthesis pathway and higher electricity demand associated with MEA production. Although acidification and eutrophication impacts are dominated by upstream energy consumption for both solvents, AEEA production contributes about 90% of these impacts, slightly lower than the corresponding contribution of MEA (approximately 98%). When process operation and solvent production are considered together, AEEA consistently demonstrates a lower overall environmental footprint across most impact categories examined (8% lower single score). By coupling process-level simulation with life cycle assessment, this study shows that AEEA offers improved CO₂ loading capacity, reduced regeneration energy demand, and a lower life-cycle environmental impact relative to MEA under the conditions investigated. These results highlight a trade-off between the higher production-stage burden of AEEA and its improved operational performance during CO₂ capture.