Characterization of novel organic corrosion inhibitors under flowing conditions

Abstract

Adding corrosion inhibitors has been found to be one of the most effective methods in preventing corrosion. The corrosion inhibitors are chemical compounds that are added to the system to reduce the corrosion rate. The inhibition efficiencies of three novel organic corrosion inhibitors in 1N HCl were evaluated and investigated under static and flowing conditions by using a modified rotating disk apparatus. The three new corrosion inhibitors were synthesized at the Chemistry Department at King Fahd University of Petroleum & Minerals, Saudi Arabia. The effects of flow speeds and concentration of the inhibitors on inhibition performance were studied through electrochemical measurements including Tafel Plots and Linear Polarization techniques. The peak-value phenomenon for Inhibitors (a), (b) and (c) were exhibited at inhibitor concentration of 100, 25, 25 ppm respectively at static condition. However, at flowing conditions the optimum concentration of inhibitor (b) was shifted to 50 ppm while increasing the flow speed did not affect the optimum concentrations for the other two inhibitors. Inhibitors (a) and (b) showed better inhibition efficiencies at static condition than at flowing conditions but inhibitor (c) showed better inhibition efficiency at flowing conditions. Among the three inhibitors, inhibitor (a) showed the best inhibition efficiency for all the tested speeds and concentrations. The adsorption of the three inhibitors under static and flowing conditions obeyed Langmuir's isotherm for all flow speeds and inhibitor concentrations.