The synergistic inhibition effect between imidazoline and the oxide film on L360 steel in CO₂/H₂S systems

Abstract

Purpose

The aim of the present paper was to investigate the inhibition performance of the OF and/or IM on L360 steel in CO₂/H₂S environments. The pipeline steel surface usually has been pre-treated before using in the oil/gas field, such as by passivation, blackening, and phosphiding. The effectiveness of inhibition can vary because there are many differences between the metal matrix and the treated film.

Design/methodology/approach

Imidazoline (IM) was synthesized by using oleic acid and diethylenetriamine, and its composition was verified using Fourier transform infrared spectroscopy. The oxide film (OF) covering a sample of L360 steel was characterized using X-ray diffraction, and its surface morphology was observed using scanning electron microscope. Electrochemical impedance spectroscopy measurements were conducted to study the inhibition performance of IM- and/or OF-covered L360 steel in the CO₂/H₂S environments.

Findings

The results show that IM and OF can prevent corrosion on L360 steel in CO₂/H₂S environments, and the synergistic inhibition effect of IM and OF was very evident. A possible model is proposed to explain the synergistic inhibition effect in the CO₂/H₂S environments of IM and OF on L360 steel.

Originality/value

Few reports have concerned the effect of the OF on the inhibitor’s performance, especially in CO₂/H₂S systems. The aim of the present study was to investigate the inhibition performance of the OF and/or IM on L360 steel in CO₂/H₂S environments. A model is proposed to explain the synergistic inhibition effect mechanism between IM and OF.

Citation

Chen, G., Li, L., Ouyang, J., Zhu, Z., Wang, F., Wang, Y., Xue, J. and Zhao, J. (2015), "The synergistic inhibition effect between imidazoline and the oxide film on L360 steel in CO₂/H₂S systems", Anti-Corrosion Methods and Materials, Vol. 62 No. 3, pp. 143-148. https://doi.org/10.1108/ACMM-01-2015-1490