Thermal degradation of amines for CO2 capture

Amine scrubbing will be an important technology for CO2 capture and storage. The degradation of the amine at 100–150 °C limits the maximum T/P and therefore the energy performance of the solvent regeneration. This is a review of the rate, products, and mechanisms of thermal degradation. Primary and secondary ethanolamines and ethylenediamines degrade at 100–130 °C as they form cyclic oxazolidinones and ureas. Tertiary amines can be more resistant to degradation if they do not include methyl and ethanol groups. Piperazine structures and long chain diamines such as hexamethylenediamine degrade by ring opening and closing and can be used at 150–160 °C. Thermal degradation can produce products that are more volatile than the parent amines.

► Alkanolamines and ethylenediamines degrade readily by ring formation.
► Tertiary amines degrade slower by transalkylation and elimination.
► Piperazine and its derivatives are resistant to degradation by ring opening.
► Amine blends frequently degrade faster than their components.