Study of 2-Ethanolamine degradation

One major drawback of the post-combustion CO2 capture using conventional amine solvents is solvent
degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the
CO2 capture process since it may cause corrosion, foaming and fouling, possibly inducing a decrease
of the solvent efficiency and high additional operating costs due to solvent replacement.
In order to study degradation of conventional amine solvents as well as degradation of novel solvents,
a degradation test rig has been built at the University of Liège in collaboration with the company
Laborelec, member of the GDF SUEZ group. Since degradation generally occurs within a few months
in real plant conditions, this equipment has been designed to allow the study of different degradation
mechanisms under accelerated conditions, at high temperatures (up to 140°C) and high partial
pressures in oxygen and CO2 (total pressure up to 20 bar with varying gas composition). An advantage
of this degradation test rig is that it can be used in batch as well as in semi-batch mode with constant
gas flow. High gas-liquid contact efficiency is also ensured thanks to a mechanical agitation system
combined with gas bubbling. For a typical run, 300g of aqueous amine solution (30 wt % MEA in
water) is introduced into the reactor and degraded during two weeks. The degraded solutions are then
analysed using high pressure liquid chromatography (HPLC) for MEA quantification and gas
chromatography with flame ionization detector (GC-FID) for the characterization of degradation
products. The gas phase is analysed by Fourier Transform Infra Red spectroscopy.
The final objective of this work is to implement the data obtained from experimental results on the
degradation test rig into an existing simulation model that has been developed based on an existing
pilot plant.