17th Asian Pacific Corrosion Control Conference

Abstract

Abstract: Being an acidic gas, dissolved carbon dioxide can decrease the pH of the solution which could lead to severe corrosion. The plant integrity can be effected by material corrosion as the efficiency will decline and requires costly maintenance. During carbon-capture process, the acid-gas loading areas, such as absorption unit, liquid storage, lean-rich exchanger, and regenerator unit, are more prone to corrosion. The corrosion rate for carbon steel, aluminium, copper, and stainless steel is studied by electrochemical as well as weight-loss method in aqueous ionic liquid-CO2 environment. The corrosion current densities were determined by extrapolation from Tafel plots and by polarization-resistance measurements. The characterization was done by SEM. The studies reveal that the corrosion behaviour of the tested materials in a novel ionic liquid, Triethylenetetrammonium Lactate (TETAL), shows corrosion inhibition. It is found that stainless steel proved resistant in both carbon-dioxide free and carbonated dilute ionic liquid systems. Both the methods also showed approximately the same corrosion rate. A mechanism is proposed to identify the most important agents responsible for the corrosion behaviour of the tested metals.
Keywords: CO2 Loading, Ionic Liquid (IL), Tafel plot, Linear Polarization, Corrosion Rate