Kinetics of the Oxidative Degradation of Aqueous Monoethanolamine in a Flue Gas Treating Unit

An investigation of the kinetics of the oxidative degradation of aqueous monoethanolamine (MEA) was conducted in a 300-mL autoclave in the temperature range 393−443 K and MEA concentration range 2−11 kmol/m 3 at 241−345 kPa O 2 pressure (i.e., O 2 concentration range). The results show that MEA oxidative degradation depends on both the O 2 and the initial MEA concentrations, as well as the temperature, according to the intrinsic kinetic model − r MEA = 2.5 × 10 5 e -(66 288.9/ RT ) [MEA][O 2 ] 1.5 . This work represents the first attempt at both obtaining intrinsic kinetic data for the oxidative degradation of MEA and formulating a kinetic model that fits the data based on the initial rate. The values obtained for the reaction orders for MEA and O 2 imply that oxidative degradation of MEA is more sensitive to increases in the O 2 concentration than in the MEA concentration. It also shows that, even though our experimental conditions enabled us to model the reaction as a homogeneous liquid-phase reaction, MEA oxidative degradation itself is not an elementary reaction.