Henry’s Volatility of Acetaldehyde from Amine Solvents and Its Application in Estimating CO₂ Capture System Emissions

Aldehydes, including formaldehyde and acetaldehyde, are commonly observed as amine solvent degradation products in carbon capture systems. These degradation products have the potential to cause environmental consequences if they migrate to the flue gas and are emitted from CO2 capture systems. A better understanding of the Henry’s volatility coefficients of these compounds is needed to estimate the gas-phase partitioning of these compounds from the amine solvent and to aid in the development of proper mitigation strategies that can be implemented within CO2 capture systems. This work highlights the experimental determination of the dimensionless Henry’s volatility coefficient of acetaldehyde from unloaded and CO2 loaded amine solvents using headspace solid-phase microextraction with on-fiber derivatization and gas chromatography mass spectrometry detection. The experimental dimensionless Henry’s volatility coefficient was significantly higher from the amine solvent when compared to acetaldehyde’s partitioning coefficient from water due to a “salting out” effect from increases in ionic strength with CO2 loaded amine solutions. A linear temperature and CO2 loading dependency of the Henry’s volatility coefficient was observed with acetaldehyde from the amine solvent. The experimental Henry’s coefficient was then used to estimate gas-phase concentrations from carbon capture systems based on measured process temperatures, CO2 loading in the solvent, and acetaldehyde liquid concentration values all measured from a pilot CO2 capture system.