Impact of fly ash on monoethanolamine degradation during CO₂ capture

Fly ash contains varying amounts of transition metals depending on the fuel, combustion and also downstream emission control process. As certain transition metal ions are known to catalyze solvent degradation, the impact of fly ash is an important consideration for a post-combustion CO₂ capture process. Here, five different fly ashes were screened with a representative carbon dioxide loaded aqueous monoethanolamine solution. The addition of fly ash has been found to impact oxidative degradation and product distribution significantly. Eight products have been identified and quantified by LC-TOF method. Some of the new products identified here contain a secondary amine group that could potentially nitrosate further. The rates of formation of these products were determined and found much higher with fly ash compared to MEA alone.