CO2 capture could contribute significantly to achieving emissions neutrality, reducing existing greenhouse gas inputs from industrial processes and compensating for residual emissions that are hard to eliminate. Amine-based Postcombustion Carbon Capture (PCC) is the most widely used technology in this area. However, toxic degradation products of the CO2 scrubber amines (as amines, nitrosamines, etc.) are potentially emitted to the atmosphere, impacting health and the environment.
This report forms a part of the project EURAMET / METCCUS and addresses activity 2.1, Task 2.1.6. (Deliverable 3) scoped to guide volatile nitrosamines monitoring in PCC plants. This document refers to the
requirements proposed in the Task 2.1.1 (Annexe 1) and to the method proposed in the Task 2.1.2 (Annexe 2), intended for monitoring nitrosamine emissions from the stacks (exhausts) of PCC plants utilising amine-based solvents as the carbon capture medium. Although this document guides PCC nitrosamines monitoring emissions, potentially most of the content can be of use for amines monitoring as well. It is worth mentioning that the performance of the proposed method has been demonstrated in Task 2.1.4 (Annexe 3) for a selected group of volatile nitrosamines with vapour pressures ranging from 0.005 to 0.4 kPa @ 1 atm and 20 ⁰C. In post-combustion CO2 capture plants, the conditions of the flue gas matrix, its composition, and particularly the breakdown products originated by the reactions between the amine-based scrubber and the post-combustion exhaust gas, present several specific challenges. This means that “traditional” monitoring approaches and methods – both instrumental and manual – may not be suitable to monitor the target pollutants and surely may require modifications.
This guide identifies available manual or continuous emissions (instrumental) monitoring methods for the emerging pollutants (nitrosamines and amines) potentially emitted by PCC plants. When possible, performance characteristics are presented as well as suggested sampling durations. The guide also identifies limitations and adjustments required to the methods (where relevant) due to the unique PCC flue gas characteristics of PCC plants’ flue gas. It is worth noting that the methods identified for the measurement of nitrosamines (and amines), have not been fully validated for the monitoring (sampling and measurement) of these pollutants. Therefore, currently, any result from any of these methods is subject to a large amount of unquantifiable uncertainty. Finally, two different IR-based instruments have been assessed to measure post-capture CO2 concentrations in simulated PCC stack conditions (Task 2.1.5 in the Annexe 4).
It is important to note that PCC emissions are a relatively new area within stack emissions monitoring, featured by several challenges linked to a relatively long list of new species that have not been traditionally measured in industrial stacks, including toxic and/or carcinogenic species. In addition, these pollutants are found within a non-typical gas matrix where complex multi-phase transport/emission is taking place. This document recognises that, in addition to the development of new methods, more validation and research are required in order to meet the challenges posed by PCC stack emissions. Areas where more research is required are mentioned within this guide.
