Model study on the influence of plant design, photochemistry and meteorology on atmospheric concentrations of nitrosamines and nitramines in vicinity of an amine-based CO2 capture facility

Post combustion using amine solvents is the most mature technology for the capture of CO2 from coal-fired power plants. Yet, amines atmospheric fate and their environmental and human health impacts, after their release by evaporation and solvent degradation from post combustion CO2 capture (PCCC) plants to the surrounding air, remains a key area to address in view of the worldwide installation of large-scale carbon capture and storage facilities. It is therefore crucial to test potential industrial applications with respect to plant design parameters influencing the fate of the amine degradation products. In this work, a method is developed to propose ideal PCCC plant parameters with respect to its design and operation. A risk limiting scenario was modelled on the UK's largest CO2 capture pilot plant (CCPilot100+) in Ferrybridge using the air dispersion model ADMS, such that the total nitrosamines and nitramines from the amines realised did not exceed the reported atmospheric safety limits of 0.3 ng/m3 with respect to human health in the local environment. A parametric sensitivity study was performed to determine the plant design parameters that most influenced the fate of the nitrosamines and nitramines. It was found that stack height and diameter, exit flue gas temperature and velocity are parameters of the PCCC plant can influence the total sum of nitrosamine (NS) and nitramine (NA) from +58% to −42% compared to the baseline parameterization. Environmental parameters, such as the site specific background meteorology and the background photochemistry were also inspected. Meteorology, i.e. mainly wind speed and wind flow field, affected the total NS and NA baseline concentrations from +28% to −10%, and background photochemistry from +165% −65%. In conclusion, if a PCCC plant is constructed with advantageous exhaust geometry, environmentally optimised operation conditions, and placed in an area with low background pollution, the risk associated with employing amines for capturing CO2 emissions might be reduced to a minimum.