Effect of exposure time with SO₂ as an impurity on the corrosion behaviour of pipeline steel in CCS transportation

ABSTRACT

This study was aimed at evaluating the effects of exposure time and SO₂ as one of the impurities on the corrosion behavior of steel pipeline transporting supercritical CO₂ during carbon capture and storage. Steel coupons were exposed to supercritical CO₂ with various concentrations of SO₂ for durations up to 1512 hours. Weight loss measurements were performed to evaluate the steel corrosion behavior. The weight loss results revealed a decrease in corrosion rate with an increase in exposure time which was mainly attributed to the gradual increase of the mineral layer on the steel surface. The increase in SO₂ concentration within supercritical CO₂ increased the corrosion rate from 0.0109 mm/yr to the highest value of 1.396 mm/yr. X-ray diffraction analysis revealed that the mineral layer formed on the steel surface under pure supercritical CO₂ mainly consisted of siderite while iron sulfite hydrate was observed under in the presence of SO₂.

KEYWORDS:

• Carbon steel
• supercritical CO₂
• SO₂
• weight loss method
• SEM
• XRD

Acknowledgements

This work was supported financially by the National Research Foundation (NRF), Grant UID: 81949 – South Africa.

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No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.