Impact of High SO₂ Concentration on Amine-Based CO₂ Capture Systems

This paper quantifies the severe technical and economic impacts of high sulfur dioxide (SO₂) concentrations on amine-based post-combustion CO₂ capture systems, using monoethanolamine (MEA) as the benchmark solvent. At untreated flue gas levels (≈500 ppm SO₂), irreversible reactions between SO₂ and MEA form heat-stable salts that permanently deactivate the solvent, leading to rapid degradation, corrosion, and significant operational instability. Even under the most conservative (stoichiometric) conditions, solvent losses can cost millions of dollars annually; in realistic operating environments, these costs increase by one to two orders of magnitude, raising the effective CO₂ capture cost from typical values of $40–70/t to as high as $600/t. The analysis underscores that operating amine system without SO₂ pretreatment is technically unsustainable and economically prohibitive, making upstream desulfurization or polishing scrubbers an essential prerequisite for any viable carbon capture operation.