Assessment of Internal Pipeline Corrosion Using Vernonia Amygdalina

Abstract

Previous research efforts usually consider external corrosion of the pipes in the presence of seawater, which is typical of offshore operations. In this study, the corrosion inhibition potentials of Vernonia amygdalina leaf extract was investigated to understand its efficacy in tackling internal corrosion in pipelines. Fresh leaves of bitter leaf plant were collected from a nearby farm, from which the extracts were produced using ethanol solvent. The gravimetric method was carried out at various concentrations of the plant extracts using mild steel, aluminum and galvanized steel samples cut into rectangular coupons (30cm x 20cm). The various concentrations consisting of 4ml, 6ml and 8ml of inhibitors were used to testaluminum, mild steel and galvanized steel samples in 100ml crude oil with 1.0 M of H2SO4. From the obtained results, there was a direct relationship between internal corrosion rate of the metals studied and their exposure time in the corrosive medium. For all the metals studied, there was an inverse relationship between the internal corrosion rate and the concentration of Vernonia amygdalina leaf extract in the corrosive medium. In addition, the observed inhibition efficiencies for aluminum were 31.11%, 46.67% and 57.78% at 4ml, 6ml and 8ml inhibitor concentrations respectively. Inhibition efficiencies for mild steel were 31.43%, 45.71% and 62.86%, while galvanized steel had the highest inhibition efficiencies of 44%, 64% and 72% at 4ml, 6ml and 8ml inhibitor concentrations respectively.