Field Testing of Self-Healing Metallic Coatings for Internal Corrosion Protection of Natural Gas Pipelines

Technical Report · Tue Feb 21 04:00:00 EST 2023

DOI:https://doi.org/10.2172/1957980· OSTI ID:1957980

Belarbi, Zineb ^[1]; Chinn, Richard E. ^[1]; Doğan, Ömer N. ^[1]; Carr, Patrick ^[2]; Samson, Julius ^[2]

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1. National Energy Technology Lab. (NETL), Albany, OR (United States)
2. NW Natural, Portland, OR (United States)

Internal corrosion occurs in natural gas pipelines primarily due to the presence of water, carbon dioxide, and hydrogen sulfide. Internal corrosion can eventually result in leakage, cracks, and rupture of the pipeline. The objective of this work is to mitigate internal corrosion in steel pipelines transporting natural gas using cold spray coatings. The corrosion behavior of carbon steel coated with self-healing zinc chromium (ZnCr) and zinc niobium (ZnNb) cold spray coatings was investigated in a natural gas environment. For comparison purposes, hot-dip galvanized steel (HDGS) was tested under the same conditions as cold spray coatings. The field test was performed at the NW Natural gas storage facility in Mist, Oregon. The field test was conducted in a 6-inch diameter pipe transporting wet natural gas out of an underground storage well at 500 psi and 4.4 °C. The coupons were tested for 15 and 32 days under stagnant and flow conditions, respectively. Weight loss method was used to measure the corrosion rate of metallic coatings. Post-corrosion surface characterization was performed on the specimen using a scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). Crystalline phases were determined by X-ray diffraction (XRD). The field-test results confirmed that the metallic coatings provided corrosion protection of carbon steel exposed to wet natural gas under stagnant and flow conditions. The formation of the ZnCO₃ layer on top of ZnNb and ZnCr coatings led to passivation of the coatings which helps to reduce the self-corrosion. These layers form a barrier for diffusion of corrosive species to the surface.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy and Carbon Management (FECM)
• DOE Contract Number: 89243318CFE000003
• OSTI ID: 1957980
• Report Number(s): DOE/NETL-2023/4321
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
42 ENGINEERING