Naphthenic Acid Corrosion: The Effect of Phosphorus and Non-phosphorus Inhibitors on Carbon Steel Surfaces

摘要

Naphthenic acids present in crude oils contribute to high-temperature corrosion. Corrosion caused by naphthenic acids generally occurs in the temperature range of 200-400 °C (400-750 °F). The use of inhibitors is a common corrosion mitigation strategy. Phosphorus based compounds are known to be effective in naphthenic acid corrosion control. However, some users have enforced limitations on phosphorous content, requiring application of phosphorus-free alternatives. In light of these restrictions, a systematic surface study of carbon steel surfaces treated with both phosphorous and non-phosphorus based corrosion inhibitors is proposed.Surfaces of both treated and untreated carbon steel specimens were characterized via X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy. In addition, morphological data were obtained using Vertical Scanning Interferometry (VSI). Molecular modeling was used to correlate electronic properties of the inhibitors with their reactivity.