Ionic liquids [EMIM][BF4], [EMIM][Otf] and [BMIM][Otf] as corrosion inhibitors for CO2 capture applications

We present the viability of using thermally stable, practically non-volatile ionic liquids as corrosion inhibitors in aqueous monoethanolamine systems. Carbon steel 1020, which is widely used as a construction material in CO2 capture plants, has been taken as a test material. Corrosion inhibition capabilities of typical room-temperature ionic liquids constituting imidazolium cation in concentration range a parts per thousand currency sign3% in CO2 capture applications were investigated. Electrochemical corrosion experiments using the potentiodynamic polarization technique for measuring corrosion current were carried out. Subsequent calculation of corrosion rate via Tafel fit was performed. The experimental findings suggest that the corrosion rate is significantly dependent on the process parameters, such as the CO2 loading and the presence of oxygen. In addition, the value of the corrosion rate is sensitive to the type of ionic liquid added. Moreover, the results show that ionic liquids possess the ability of suppressing severe operational problems of corrosion in typical CO2 capture plants to a reasonable extent (a parts per thousand yen50%).