Insights into the Impact of Trace SO2 on Amine Absorbents for Chemical Absorption of CO2

The impact of trace SO2 in industrial flue gas on the amine-based chemical absorption of the CO2 process is a significant concern. This work investigates the impact of trace SO2 on the chemical absorption of CO2 by four representative amine absorbents containing a primary amine group of ethanolamine (MEA), a secondary amine group of 2-(ethylamino)ethanol (EMEA), a tertiary amine group of N,N-diethylethanolamine (DEEA), and a sterically hindered amine group of 2-amino-2-methyl-1-propanol (AMP), focusing on their absorption/desorption capacity, cyclic absorption performance, CO2/SO2 selectivity, and SO2 resistance capability. Experimental results revealed that the amine absorbent of MEA with the primary amine group has the highest SO2 resistance capability, while the amine absorbent of EMEA with the tertiary amine group exhibits the lowest. In addition, CO2/SO2 selectivity investigations indicated that the amine absorbent of MEA with the primary amine group has superior selectivity for CO2 than others. Moreover, NMR analysis revealed that SO2 more significantly inhibited bicarbonate formation compared to carbamate formation, suggesting that amine absorbents prone to carbamate formation after CO2 absorption have greater SO2 resistant capability. Altogether, this work provides valuable insight into the utilization of amine absorbents for the capture of CO2 in the presence of SO2.