Chemical stability and biodegradability of new solvents for CO2 capture

Abstract

A study on thermal and chemical stability of amines has been performed for eleven chemicals, including ethanolamine (MEA), 2-amino-2-methylpropanol (AMP) and diethanolamine (DEA), trying to identify the impact of parameters such as amine function, alcohol group and steric hindrance. The chemicals were studied for 5 weeks at 135 °C, both with and without the presence of CO2 (0.5 mol/mol amine) and in contact with metal (316 SS) as well as in glass containers. In general, the presence of metal did not make an impact on the degree of degradation. As for thermal degradation without CO2, most of the compounds were relatively stable. For thermal degradation in the presence of CO2, the sterically hindered amine AMP had the highest stability, while the secondary amines had the lowest. Increasing chain length gave slightly higher stability. In comparison with biodegradation, most of the compounds showed higher thermal degradation in the presence of CO2 than for biodegradation, and compounds stable at process conditions are likely also resilient with regards to biodegradation. None of the tested chemicals has the combined desired stability under process conditions while at the same time being sufficiently biodegradable.