Possible Pathways for Oxidative Degradation of β-hydroxyl Alkanolamine for Post-combustion CO2 Capture

Solvent degradation due to the presence of oxygen is an important issue for amine-based absorption/stripping process for post-combustion carbon dioxide capture from flue gas streams. There are still some knowledge gaps in the understanding of alkanolamine oxidation so far. To explore possible degradation mechanism of alkanolamines, oxidative degradation of aqueous β-hydroxyl alkanolamine solutions without CO2 loading was investigated in the presence of 250 kPa O2 at 120 °C. The alkanolamines include monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), 2-amino-1-propanol (APN), and 2- amino-1-butanol (ABN). The anionic oxidation products were identified by anion chromatography. A possible degradation pathway for the oxidative degradation of the investigated amines is proposed to account for the formation of the carboxylic acid products.