With years of full-scale experience for pre-combustion CO2 capture, amine-based technologies are emerging as the prime contender for post-combustion CO2 capture.  However, concerns have arisen for the possible contamination of air and drinking water supplies downwind by the release of carcinogenic N-nitrosamines, following their formation by NOx reactions with amines within the capture unit.  The structure of amines has a major influence on their nitrosation potential, but has not been systematically studied under CO2 capture scenarios.  In this study, we selected an array of amines with different structural characteristics and tested these amines in a lab-scale CO2 capture reactor.  Samples from the absorber and water wash units were analyzed for total N-nitrosamine concentrations.  It was found that the total N-nitrosamine formation potential in the absorber followed the order: secondary amines = tertiary amines >> primary amines.  However, when considering potential atmospheric release, amines with alcohol functional groups give rise to lower total nitrosamine levels in the water wash unit, regardless of the order of the amino group.  Steric hindrance on the primary amino group does not affect total N-nitrosamine formation in the absorber, but has an impact on the total N-nitrosamine accumulation in the water wash unit.  The influence of amine structural characteristics should be considered in the search for an �ideal� solvent for CO2 capture to minimize environmental and health impacts related to N-nitrosamines.

Influence of amine structural characteristics on <i>N</i>-nitrosamine formation potential relevant to post-combustion carbon dioxide capture systems

246th National Meeting (2013)

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Influence of amine structural characteristics on N-nitrosamine formation potential relevant to post-combustion carbon dioxide capture systems