Electrochemical noise analysis for estimation of corrosion rate of carbon steel in crude oil

Abstract

Purpose

This paper aims to estimate the corrosion rate of the carbon steel in crude oil using the electrochemical noise (EN) analysis technique.

Design/methodology/approach

EN measurements and electrochemical impedance (EIS) spectroscopy were employed to study the corrosion behaviour of carbon steel in crude oil and the optimum conditions of the noise analysis for estimating corrosion rate of the carbon steel are discussed. The time series noise patterns were transformed into frequency domains by fast Fourier transformation, and then their power spectrum densities (PSDs) at a frequency were determined to be compared with the corrosion rate.

Findings

The PSDs of the potential and of the current varied with changing of rotation rate of electrode and immersion time. Square roots of the PSDs for the potential difference and for the currents were in positive and almost linear correlation with the corrosion rate obtained from EIS plots. In addition, the spectral noise was negatively and linearly correlated with the corrosion rate. The relationship between the corrosion rate and the spectral noise resistance was better at lower frequencies.

Research limitations/implications

It is suggested that this research is carried out for crude oils with other physical and chemical characteristics.

Practical implications

The PSD value at 3 mHz from the noise of the current and the spectral noise resistance at the same frequency are the optimum conditions for estimating corrosion rate in this research.

Originality/value

This paper arguably fills a gap in the current understanding of the interactions between corrosive species commonly found in crude feedstocks and process streams.

Citation

Ghassem Mahjani, M., Neshati, J., Parvaneh Masiha, H. and Jafarian, M. (2007), "Electrochemical noise analysis for estimation of corrosion rate of carbon steel in crude oil", Anti-Corrosion Methods and Materials, Vol. 54 No. 1, pp. 27-33. https://doi.org/10.1108/00035590710717366