A study of designer amine 4-amino-1-propyl-piperidine against the corrosion of carbon steel for application in CO2 capture

We investigated the relationship between amine structure and corrosion rates in a study of the corrosion behaviour of carbon steel in CO2-loaded 4-amino-1-propyl-piperidine (4A1PPD) solution and a series of related amines. Electrochemical measurements showed that 4A1PPD displayed the lowest corrosion rate of the amines studied, and that the corrosion rate decreased with the increase of the number of substituents on amino groups and a structural change from linear amines to cyclic amines. We also carried out a hydrothermal corrosion study using selected amines to analyse the surface morphology and composition formed on the surface of corroded carbon steel. The results suggested that the formation of a protective film was dependant on the ratio of bicarbonate/carbamate species. We confirmed that a dense FeCO3 protective film was produced on the carbon steel surface after hydrothermal corrosion treatment with CO2 rich 4A1PPD solution. Our results demonstrate that the 4A1PPD designer amine with a cyclic structure shows good corrosion properties for use in post-combustion CO2 capture and resulted in significantly reduced corrosion on carbon steel compared to the benchmark amine, monoethanolamine.