Formation and destruction of NDELA in 30 wt% MEA (Monoethanolamine) and 50 wt% DEA (Diethanolamine) solutions

Abstract

The formation of nitrosodiethanolamine (NDELA) in a lab scale pilot was studied by feeding known amounts of nitrogen oxide and nitrogen dioxide into the gas entering the absorber. In the same pilot, the destruction by UV-irradiation of NDELA present in the solvent was studied. Two campaigns were performed, one with 30 wt% monoethanolamine (MEA) and one with 50 wt% diethanolamine (DEA). During the DEA campaign the destruction of NDELA in the water wash section was also tested. Additionally, degraded solution samples withdrawn from the pilot were tested for thermal degradation. The results show that NDELA was formed when nitrogen oxide and nitrogen dioxide were present. Destruction of NDELA with UV-light in the solvent loop was found to be slow. In the water wash section, the UV-light destroyed the NDELA effectively. NDELA was found to degrade during the thermal degradation studies at 135°C.