Aerosol Emissions of Amine-Based CO₂ Absorption System: Effects of Condensation Nuclei and Operating Conditions

Abstract

Amine emissions from a post-combustion CO2 capture process can lead to solvent loss and serious environmental issues. The emission characteristics of amine mixtures and influencing factors are seldom reported. This work comprehensively investigated emissions of AMP (2-amino-2-methyl-1-propanol)/MEA (monoethanolamine) from a 3.6 Nm3/h flue gas CO2 capture platform. The condensation nuclei in flue gas dominated the generation of amine aerosols and resulted in a heavy total amine loss of over 1400 mg/Nm3, which is equivalent to 5.88 kg/t CO2 captured under the high nuclei concentration scenario. Inside the absorber, a higher CO2 concentration and lower lean solvent CO2 loading can significantly promote the growth of aerosols due to the intensive reaction of CO2 absorption. The maximum amine emissions were observed at 8–12 vol % CO2. The flue gas temperature and liquid/gas ratio had insignificant effects on aerosol emissions, while amine emissions after the absorber increased 340–500% as the lean solvent temperature increased from 30 to 50 °C. A synergistic control strategy of nuclei pretreatment, operating optimization, and water scrubbing can effectively reduce amine emissions to 4.0 mg/Nm3 MEA and 8.3 mg/Nm3 AMP.