Comparison of MEA degradation in pilot-scale with lab-scale experiments

Abstract

To understand which part of the CO2 amine-based system is mostly responsible of amine degradation, MEA degradation under real CO2 capture conditions is compared with two laboratory experiments; a thermal degradation experiment representative of the stripper conditions (MEA 30 wt%, CO2 loaded, α=0.5, 135 °C) and an oxidative degradation experiment representative of the absorber conditions (MEA 30 wt%, CO2 loaded, α=0.4, sparged with air+CO2, 55 °C). Liquid Chromatography-Mass Spectrometry (LC-MS) was used for the quantification of the remaining amine and Gas Chromatography-Mass Spectrometry (GC-MS) was used for the identification and quantification of the main degradation compounds. This study suggests that MEA degradation in the pilot plant is more dominated by oxidative degradation than by thermal degradation. It is also found that reactions between MEA and carboxylic acids present in the solution may play a significant role in solvent degradation. This implies that carboxylic acids, usually referred to as “Heat Stable Salts”, are not stable and can react further to give more complex compounds.