Mechanism and kinetics of oxidative degradation of carbon dioxide-loaded concentrated aqueous MEA/MDEA blends during carbon dioxide absorption from flue gas streams of industrial power systems.

摘要

Alkanolamines such as monoethanolamine (MEA) and diethanolamine (DEA) have been used industrially for a number of years for CO2 removal from flue gas streams, and there are differences in performance in their reactivities or rates of CO2 absorption. Additionally, they can also be degraded by undergoing irreversible reaction with CO2 and other flue gas components such as oxygen (O2), sulphur dioxide (SO2), and certain other impurities that are normally present in the flue gas streams. Degradation leads to a loss of CO2 absorption capacity and may give rise to products that are difficult to dispose of in terms of environmental standards.; It is widely known that by blending a primary or secondary alkanolamine with a tertiary alkanolamine, bulk CO2 removal can easily be accomplished while minimizing cost for regeneration energy. However, in order to obtain a good strategy for prevention of degradation of mixed amines, a good understanding of the nature of degradation (involving products, stoichiometry, mechanisms, and kinetics) is necessary. This study identified the degradation products and investigated the mechanism and kinetics of degradation of MEA-MDEA-H 2O-O2, MEA-MDEA-H2O-CO2, and MEA-MDEA-H 2O-O2-CO2 systems. (Abstract shortened by UMI.)