Corrosion Prevention of Cast Iron Industrial Water Pipes: A Preliminary Comparative Study of Hexamine and Aniline Inhibitors

Abstract

Using cast iron pipes in various industrial and water systems is experiencing a majorproblem of corrosion occurrence. Hence the operation and maintenance of these pipesbecome costly and infeasible. Corrosion inhibitors have a great role in decreasing pipescorrosion rate. In this study, the inhibition effect by applying two inhibitors ofhexamethylenetetramine (hexamine) and aniline on cast iron pipes was studied.Experimental measurements of the corrosion behavior of cast iron pipes was thoroughlyexamined in three aqueous salt solutions of 2% NaCl, 2% Na 2 SO 4 and 2% CaCO 3 . Thecorrosion inhibition efficiency of the cast iron pipes by aniline or hexamine in the threeaqueous salt aqueous solutions was investigated at constant temperature and for differenttime intervals. Corrosion rates of the pipes were determined using weight loss technique.It has been found that, for the corrosion of cast iron pipes, a satisfactory inhibitionefficiency is observed for a concentration close to 150 ppm hexamine and 150 ppmaniline over the whole aqueous salt solutions tested in the work. The results showed thatat the same inhibitor concentration and temperature, aniline exhibits higher inhibitioncorrosion efficiency on cast iron pipes than the efficiency achieved by hexamine.