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2-Ethanolamine (MEA) degradation has been studied under varying conditions of relevance to postcombustion CO 2 capture. Degradation experiments performed in the laboratory were chosen to be representative of the conditions in a CO 2 capture plant facility. The thermal degradation of MEA was investigated in closed-batch experiments at 135 °C at different loadings. MEA degradation was also studied in oxidative conditions without additives or by adding FeSO 4 /fly ash. These experiments were compared with three MEA campaigns performed in pilot plants at Tiller (Norway), Esbjerg (Denmark), and Longannet (U.K.). The same analytical procedures were used to identify and quantify the main degradation compounds. Mechanisms are also proposed to account for the observed degradation products. For the Tiller campaign 99.7% of nitrogen containing compounds in the liquid at the end of the campaign was accounted for by the solvent and quantified degradation products.

Oxidative degradation experiments on 2-ethanolamine (MEA) were performed at four different oxygen concentrations and at two temperatures. MEA loss and degradation product build-up were measured. Increasing the temperature from 55 to 75 °C was shown to have higher impact on the MEA loss than increasing the oxygen concentration from 21 to 98%. Liquid end sample analyses were performed for all experiments and overall nitrogen balance tests were conducted for the experiments at 21% O2 (run 2), 50% O2 and 98% O2. Analysis of liquid and gas phase ammonia and MEA in the solvent was found to give a good overall picture of degradation in the MEA system. The degradation products formed at the different oxygen concentrations were the same as described in earlier literature. However, it was found that oxygen affects the formation of the individual degradation products differently. At 75 o C the development of degradation product concentrations with time was more complex. Laboratory reaction experiments were used to verify the formation of certain degradation products from some of the suggested mechanisms.

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Two of the main challenges in post-combustion CO2 capture with ethanolamine are solvent degradation and material corrosion. It has been shown that there is a correlation between degradation and corrosion. The present paper examines this correlation by studying the effect of 10 MEA degradation products on corrosion. Thermal degradation experiments were conducted under stripper conditions for 5 weeks. 30wt% MEA solution with 1wt% of the various degradation products were placed in 316 SS cylinders and stored in a thermostat chamber at 135 °C. ICP-MS was used for the metal concentration analyses for all the solutions, while ion chromatography was used for the quantitative determination of heat stable salts anions and MEA concentrations. The solutions were also analyzed for degradation products in order to study the formation and thermal stability of these compounds. For corrosion monitoring, in addition to ICP-MS analyses, SEM-EDS was used for examining the cylinders surface morphology and elemental composition while XRD was used for corrosion product identification. In the present paper, the influence of the secondary degradation products on corrosion is studied. Results show that some specific degradation products, like bicine, HeGly and HEEDA enhance corrosion while others don't seem to have a significant effect on corrosion of stainless steel.