Multi-Layer Barrier Coating to Retrofit Natural Gas Pipelines

Bulk transportation of CO2 and hydrogen is a crucial development in our efforts to reach net zero by 2050.

While using the extensive US 320,000-mile grid of natural gas transmission pipelines seems the simplest, fastest and most cost-effective solution, those pipes suffer (i) strong corrosion from carbonic acid in the case of CO2, and (ii) hydrogen embrittlement leading to high leak rates and catastrophic failures when blending even small percentages of hydrogen with natural gas.

We have developed a patent-pending coating that is inert to carbonic acid and impermeable to hydrogen. Dense oxide and nitride layers have an extremely low hydrogen diffusivity that can effectively delay hydrogen ingress into the steel substrate, yet they are not widely used because of their poor mechanical durability and their failure as long-term solution. Despite that, when alternated with metallic layers of the same base metal in metal-oxide multilayer composite structures (such as aluminum/aluminum oxide), three peculiar properties can be observed. (i) Formation of a physical barrier to hydrogen permeation thanks to the development of extended space-charge zones at the metal/oxide interface, which repel incoming positively charged hydrogen ions diffusing in the oxide. (ii) Improved adhesion to the substrate thanks to the metallic interlayer that provides physical and mechanical compatibility between the metallic substrate and the oxide layer, thus preventing delamination. (iii) Enhanced resistance to mechanical damage thanks to the strong micro-cracking resistance and the self-healing behavior of the multi-layer composite structure.

In this study, we produced several multi-layer composite coatings with different structures and demonstrated their hydrogen-barrier effect through hydrogen permeability testing using a Devanathan-Stachurski permeation cell, both in the as-deposited and in a damaged state. The results were compared to identify the best structure for field application. Last, we will show a novel application method we developed to apply the coating onto the internal surface of pipelines using a smart pig.

About the Author: Gianluca Roscioli

Gianluca is the founder and CEO of Arculus. With nearly a decade of research experience in materials engineering and metallurgy, he is an expert in the design and fabrication of setups for in-situ scanning electron microscopy experiments as well as failure analysis. He holds a doctorate in Materials Science and Engineering from MIT, an M.Sc. in Materials Engineering and Nanotechnology from Politecnico di Milano, and an M.Sc. in Materials Engineering from Politecnico di Torino.

N2 Solutions and Arculus Strategic Partnership

Our well-established and integrated logistics network along the Gulf Coast ensures that customers receive our nitrogen services quickly and efficiently.

N2 Solutions remains attentive to our customers' needs and continues to invest in assets that strengthen these partnerships.

Arculus serves as our midstream strategic partner, specializing in the Gulf Coast pipeline systems with a focus on the CO2 and hydrogen markets.

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About N2 Solutions

N2 Solutions strengthens their position as a nitrogen services leader with the acquisition of PFS Nitrogen Services, expanding its locations and product offerings. With pump trucks, nitrogen transports, pipeline chemical solutions, pig tracking, and pipe freeze technology, N2 delivers cost-effective solutions to energy, industrial, chemical, and pipeline clients. Together, N2 Solutions and PFS set a new standard of excellence in nitrogen solutions for their customers.