Detection of Degradation Products of Monoethanolamine- a Post-combustion Co2 Capture Solvent

Using solid phase extraction (SPE) combined with HPLCfluorescence/photodiode array (PDA) detection several low molecular-weight alkylamines (including ethylamine and propylamine) have been detected in the gas-phase, released during the oxidative/thermal degradation of monoethanolamine (MEA), an amine-based postcombustion CO2 capture solvent. In this study, a 30 wt% aqueous MEA solution was degraded in the presence of a 13% CO2, 10% O2, 77% N2 gas stream, and temperature of 60°C, over a period of 124 hours. Mild carbon-steel metal shavings were added to the aqueous amine solution to catalyse degradation and simulate conditions similar to that found under typical operating conditions of an amine-based PCC plant. Samples of the exhaust gas were collected at regular intervals (every 4-6 hours), by drawing a portion of the exhaust gas stream into a XAD-7 sorbent cartridge coated in 10% NBD-Cl by weight. Samples were collected over a 50 min period, desorbed, and analysed for the presence of low molecular-weight alkylamines.