Mechanism and Kinetics of Nucleation and Growth in Amine Aerosols for Post-Combustion Carbon Capture

Abstract As the major component of organic amine emission, amine aerosol can generate the substantial secondary pollutants, posing serious environmental impacts and hindering the large-scale deployment of absorption carbon capture. The existing studies have proposed several end-of-pipe strategies to achieve 99% removal within a reasonable cost range while it is still challenging. It is necessary to elucidate the nucleation and growth mechanisms of amine aerosols. Herein we investigate the mechanism and kinetics of amine nucleation and growth by molecular dynamics simulation, quantum chemistry calculation, and experiment. Molecular dynamics simulation results show that the aerosol nucleation process follows a typical growth pathway characterized by mutual attraction, collision-coalescence, and nucleation. The results show that, compared with the nucleation process without chemical reactions, the reaction energy barrier of the rate-determining step in the nucleation process involving chemical reactions is reduced by 16.56 kJ/mol, reaching 11.55 kJ/mol. The reaction rate of the rate-determining step is 1.214 × 10–9 s–1, which is 3 orders of magnitude higher than that of the nonreactive reaction. This finding is further verified by structural characterization using FTIR experiments. It is expected to provide further mechanistic insights into the removal of amine aerosols.