Influence of dissolved metals and oxidative degradation inhibitors on the oxidative and thermal degradation of monoethanolamine in post-combustion CO2 capture

In the present work, the influence of metal ions and oxidative degradation inhibitors on the stability of monoethanolamine solvents (MEA) is studied. Solvent degradation induces additional costs and impacts the environmental balance of the CO2 capture process as well as its efficiency. The two main degradation pathways of MEA are studied under accelerated conditions: oxidative degradation with continuous gas feed and thermal degradation in batch reactors. It is confirmed that metal ions (resulting from solvent impurities and wall leaching) enhance the oxidative degradation of MEA, while they do not impact its thermal degradation. Moreover, different oxidative degradation inhibitors are tested with varying results according to the inhibitor. It appears that at the selected concentration, radical scavengers like Inhibitor A and DMTD (2,5-dimercapto-1,3,4-thiadiazole) are more efficient than chelating agents like HEDP (1-hydroxyethylidene diphosphonic acid) at inhibiting oxidative degradation. Furthermore, a...