Amine-based carbon capture through an environmental lens: Amine emissions and associated implications

Amine-based chemical absorption stands as one of the most established and widely employed technologies for carbon capture applications from point sources. However, emissions of amine solvents and their degradation products into the environment may pose potential adverse effects on both the environment and human health. In this review, we examine literature findings pertaining to sampling and analysis methods, emission levels, environmental impact, and health hazards associated with amines and their degradation products. Various online and offline methods were used to measure these compounds, acknowledging the potential for varied results and underscoring the necessity of establishing guidelines or standard operating procedures for measurement methods. The amine and their degradation products emission levels measured at the stack fluctuate significantly due to differing emission mitigation measures, flue gas conditions, and operational parameters. Mitigation strategies such as water wash (reducing more than half of amine emissions), acid wash (>90 %, particularly effective for removing ammonia), and Brownian Demister Units (>97 %) have been shown to substantially reduce emissions. Several studies have demonstrated the potential aquatic and inhalation toxicity of amines and their degradation products. Occupational health concerns may arise if exposure concentrations exceed several milligrams per cubic meter. Despite advancements, analytical challenges persist in investigating amine emissions, necessitating future studies aimed at establishing standard analytical methods, and improving emission prediction models to guide environmental agencies in setting emission limit values, encompassing both amines and their degradation products.