NETL Develops Cold-Spray Coating
Researchers from the National Energy Technology Laboratory (NETL) have developed a new self-healing cold spray coating for internal pipeline corrosion protection.
According to the release, the invention can help protect against corrosion in natural gas, hydrogen and carbon dioxide pipelines, preventing failure events such as explosions and methane emissions.
NETL’s Ömer Dogan, who worked on the innovation, stated that internal pipeline corrosion is a common problem. Dogan worked alongside NETL researchers Joseph Tylczak, Margaret Ziomek-Moroz and Zineb Belarbi.
“Internal corrosion in pipelines primarily is due to the presence of water, carbon dioxide, and hydrogen sulfide contained in natural gas,” Dogan explained. “Internal corrosion can eventually result in leakage, cracks, and rupture of the pipeline leading to explosion hazards and methane emissions.”
An invention reported by researchers from #NETL can help protect against corrosion in pipelines that carry natural gas, natural gas blended with hydrogen, and carbon dioxide. Read more: https://t.co/Pa8bDGakck pic.twitter.com/D7YKvWTrVL— NETL (@NETL_DOE) August 15, 2023
The release explains that traditional approaches to fighting pipeline corrosion include the use of inhibitors or organic coatings such as fusion-bonded epoxy and polyurethane. However, the challenge with the injection of inhibitors in natural gas or carbon dioxide pipelines is reportedly the difficulty of transporting the inhibitor along the pipelines.
Dogan stated that another approach would be to use sacrificial coatings, or anodes, to protect the pipelines and equipment from internal corrosion. The anode reportedly undergoes oxidation more than the metal surface it protects, essentially stopping oxidation on the metal. However, Dogan said that these anodes tend to dissolve too fast in natural gas pipelines.
“The invention consists of a new zinc-rich material that creates an effective protective layer which resists dissolution compared to existing zinc sacrificial coatings,” Dogan said. "This new material can be applied to steel structures in a cold spray process to protect them from the effects of corrosion.”
According to the release, cold spray is a high-energy solid-state coating and powder consolidation process for applications of metals, metal alloys and metal blends. Cold spray reportedly uses an electrically heated high-pressure carrier gas, similar to nitrogen or helium, to accelerate metal powders through a supersonic nozzle for particle adhesion.
The coating can reportedly be applied to the interior of a pipeline through the use of a robotic cold spray device attached to a pipeline pig.
The report adds that some of the features of the zinc-rich coating include:
Other Pipeline Coatings Research
Last year, researchers from Flinders University in Australia recently developed a smart coating for pipelines that can remove mercury from water while preventing corrosion and solvent damage. The coating can also reportedly prevent acid and water damage of concrete surfaces.
The article, “Processes for coating surfaces with a copolymer made from sulfur and dicyclopentadiene,” was authored by Maximilian Mann, Dr. Bowen Zhang, Samuel J. Tonkin, Christopher T. Gibson, Zhongfan Jia, Dr. Tom Hasell and Justin M. Chalker and was recently published in the journal Polymer Chemistry.
According to the study, after a curing process at 140 C (284 F) and due to a reaction between the sulfur and DCPD, the material was rendered insoluble and resistant to acids and solvents. Researchers then coated silica gel with the soluble oligomer to test mercury removal from water.
100 milligrams of the coated silica were added to a solution of water and mercury, then agitated using an end-over-end mixer. This test was repeated, and the coating showed “highly effective” mercury absorption, with the uncured sample removing greater than 99% of mercury within two hours and the cured samples removing at least 92% of mercury in the same time.
To test the coating’s protection from corrosion and solvents, the team applied the coating technique to metal, concrete and polyvinyl chloride. Additionally, the use was extended to cement and tests showed protection from both acid and water penetration.
The research team reported that the coating is repairable from scratches and other damage with heat application. This process can take place due to the coating’s chemical structure, allowing sulfur-sulfur bonds to be broken and reformed.
The study was conducted in the United Kingdom in an exchange at Hasell's University of Liverpool lab as part of an ongoing collaboration between the Chalker Lab and Hasell Lab. The project was funded by the Australian Research Council.