Thermal degradation of monoethanolamine at stripper conditions

Thermal degradation of monethanolamine (MEA) is quantified as a function of initial amine concentration, CO2 loading, and temperature over a range of expected stripper conditions in an amine absorber/stripper unit. The sum of the degradation products N,N'-di(2-hydroxyethyl)urea, 1-(2-hydroxyethyl)-2-imidazolidone, and N-(2-hydroxyethyl)ethylenediamine make up the majority of total MEA loss. The temperature dependent rate constant has an activation energy similar to diethanolamine (DEA) of 29 kcal/mole which corresponds to a quadrupling of the degradation rate when the stripper temperature is increased 17 degrees C. At 135 degrees C the degradation rate varies from 2.5 to 6% per week. Using speciation data from an Aspen(R) model of a stripper unit, losses in the packing are significant, but the majority of MEA loss occurs in the reboiler and reboiler sump. Thermal degradation is minor when the reboiler temperature is held below 110 degrees C. (C) 2008 Elsevier Ltd. All rights reserved