Carbon steel is one of the most commonly used metals in the oil, gas, and hydrocarbons transport industry, given its mechanical properties and low production cost; however, its low corrosion resistance to different aggressive environments has been considerably reported. Worldwide, there is an interest in mitigating corrosion and minimizing the associated cost. Inhibitors have become one of the best practical methods to avoid internal corrosion damage, especially in hydrocarbons transport lines. This investigation aims to develop and evaluate the molecules n-furfuryil-aniline (NFA) and n-furil-c-phenyl-nitrone (NFCPN) in 3% NaCl on low carbon steel using Tafel polarization and impedance spectroscopy measurement techniques. Concentrations of the molecule of 5, 10, 25, 50, and 100 ppm were used in this study. The results show that the inhibition efficiencies increased in the presence of the molecules. The inhibitors presented efficiencies up to 80% showing that the inhibitors are effective in helping to reduce and slowing down the corrosion process that occurs to the carbon steel samples evaluated.
In the hydrocarbon industry, internal corrosion is one of the most worrisome threats because it can cause catastrophic failures in the pipelines and cause harm to people and the environment. Some authors mention that internal corrosion damage is due to components such as H2S, CO2, mercaptans, sulfate-reducing bacteria, and suspended solids. These variables lead to thickness losses in the ducts, which contributes to the increase in the rate of deterioration.1 2 3 study reported by Askari et al, shows that the internal corrosion rate can be so high that it can consume the 3-6mm allowed for the pipeline in a year, which leads to irreparable economic losses.4 One of the most used methods to control internal corrosion is corrosion inhibitors, thanks to their low cost, availability, and efficiency. A corrosion inhibitor is a chemical substance used in quantities of the order of ppm, and its primary function is to adsorb on the metal surface to prevent the interaction of the corrosive species in the fluid and the metal structure. Even though there are many corrosion inhibitors, there is always room for more efficient and cost-effective corrosion inhibitors that will help the economics of operators. Thus, the search for new efficient and cost-effective organic corrosion inhibitors has been going on for the last years, and it is a very competitive business.5 Aouniti et al, highlights the behavior of 2-acetyl thiophene, which can be easily protonated due to its thiophene derivative. These molecules contain planar aromatic benzene and thiophene rings and also contain S and N atoms and π electrons.6 Also, Hamadi et al, report that glutaminic acid can be an effective corrosion inhibitor due to stabilizing its adsorption on the metal surface by the oxygen atoms that exist in its structure.7