Health & Environmental Research Online (HERO)


Print Feedback Export to File
8723593 
Journal Article 
The role of methyl diethanolamine (MDEA) in preventing the oxidative degradation of CO2 loaded and concentrated aqueous monoethanolamine (MEA)-MDEA blends during CO2 absorption from flue gases 
Lawal, O; Bello, A; Idem, R 
2005 
Yes 
Industrial and Engineering Chemistry Research
ISSN: 0888-5885
EISSN: 1520-5045 
44 
6 
1874-1896 
English 
The products and pathway for the oxidative degradation of CO 2-loaded and concentrated aqueous solution of monoethanolamine (MEA)/methyl diethanolamine (MDEA) mixture (i.e., MEA-MDEA-H2O- CO2 system) were evaluated and compared with those for the MEA-H 2O-CO2 system in a stirred cell reactor at temperatures in the range of 55-120°C, overall amine concentration in the range of 5-9 mol/L, MDEA/MEA ratio of 0-0.4, CO2 loading in the range of 0-0.53 mol/mol of total amine, and O2 pressure of 250 kPa in order to determine the role of MDEA in preventing MEA degradation. The results showed that fewer degradation products were obtained for the MEA-H2O-O 2 system for both the CO2-loaded and CO2-free cases as compared with the MEA-MDEA-H2O-O2 system. However, the addition of MDEA drastically reduced the extent of MEA degradation as well as the amount of nonenvironmentally benign degradation products. Our overall results indicate that, under our experimental conditions, MDEA is more prone to oxidative degradation and, when used in a mixture with MEA, is preferentially degraded to protect MEA. Our results further show that even in an initially O2-free environment, O2 is produced as a byproduct of CO2-induced degradation, thereby eventually generating an oxidative degradation environment for the two systems. 2005 American Chemical Society.