Volatile nitrosamine manual stack monitoring method: sampling validation and performance assessment on stack simulated conditions

• Developed a test bench for carbon capture emissions flue gas simulated conditions • 1 st validation data on stack emissions monitoring methods for volatile nitrosamines • Sampling recovery depends on the volatility and chemical structure of the species • The method could be applied to other species of similar volatilities and structures • Low volatility species (e.g. NDELA, EHEN) will require a different sampling method Degradation products of sorbent amines used in Post Combustion CO 2 Capture (PCC) (amines, nitrosamines, etc.) are potentially emitted to the atmosphere, impacting health and the environment. This paper proposes and validates for the first time a manual stack sampling method for monitoring nitrosamine emissions, using a purpose-built test bench and simulating nitrosamine sampling through monitoring tests under controlled conditions mimicking those of a PPC plant. The method uses isokinetic sampling (due to the presence of water droplets in the PPC flue gas), a combination of liquid sampling (three impingers in series) and dry sampling cartridges. Collected samples were refrigerated and send to for laboratory analysis (using a Gas Chromatography - Thermal Energy Analyser). In terms of the recovered mass of the target analytes, the method was successfully validated for the five more volatile compounds (NDMA, NMEA, NDEA, NDPA, and NPIP), while the three less volatile nitrosamine’s (NDBA, NPYR, and NMOR) had recoveries of 75-80%. However, based on the same experimental data but using the criterion of recovering in the last impinger less than 5% of the total (for each species), only the linear nitrosamines with medium volatility failed, NDPA and NDBA, capturing 11 and 22% respectively. As expected, these last two nitrosamines were also found in sizeable amounts in the back-end cartridge, demonstrating significant breakthrough from all the impingers. In spite of the general good recovery of the method for volatile nitrosamines, the results for some of the semi-volatile species show that is advisable to enhance the method to achieve a recovery closer to 100% for all the nitrosamines. Two simple proposals to achieve that goal are discussed. The sampling recovery depends on the volatility and chemical structure of the specific nitrosamines. The conclusions presented here could be carefully extrapolated to other species with similar volatilities and structures, but not to low volatile nitrosamines which will require different sample media to be sampled, for that reason they are outside of the scope of this work.