Abstract
Aminoethanol is generally used for carbon dioxide recovery as a solvent at purification of natural gas. Steels are severely corroded in aqueous solution of aminoethanol absorbing carbon dioxide at high temperatures above 60°C. In this study, corrosion and inhibition of iron were investigated in an aqueous solution containing aminoethanol at high concentration, 8.5M (52% in volume), by weight loss measurements, spectroscopic analysis of dissolved ferrous ion, and a potentiostatic polarization curve technique. Aminoal kanes containing carbon numbers from 8 to 18 were used as corrosion inhibitors against iron corrosion in the aqueous solution. 1-Aminododecane and 1-aminohexadecane were found to inhibit corrosion effectively in the aqueous solution at 80°C, but to decrease remarkably corrosion inhibitor efficiency at temperatures higher than 80°C. It is considered that these amines are chemisorbed on the iron surface and inhibit the anodic reaction of iron. The critical temperature for chemisorption of 1-aminohexadecane is concluded to be between 80 and 90°C.
