NETL (U.S. Department of Energy's International Laboratory) researchers have developed a novel self-healing, zinc-rich spray coating for corrosion protection of pipelines. This coating effectively prevents the internal corrosion of natural gas, hydrogen, and carbon dioxide from leaking through the pipeline, thereby preventing catastrophic events caused by gas explosions and the release of toxic substances.
NETL, as a key laboratory in the United States driving energy innovation and sustainable development, is committed to providing cost-effective and reliable energy technology solutions to society, while developing carbon management technologies throughout the entire lifecycle to achieve environmental sustainability.
NETL's self-healing cold spray coating technology addresses the primary causes of corrosion in pipelines – water, carbon dioxide, and hydrogen sulfide present in natural gas – by utilizing a new, high-zinc material. This material forms an effective protective layer, preventing dissolution, and is superior to existing zinc sacrificial coatings. This new material can be applied to steel structures via cold spray technology to protect them from corrosion.
According to information from Huizheng News, currently effective methods for inhibiting pipe corrosion include the use of inhibitors or organic coatings, such as using fused epoxy and polyurethane for protection. However, due to the difficulty in transporting inhibitors along the pipes, injecting inhibitors into natural gas or carbon dioxide pipelines is challenging. When using organic coatings for internal pipe protection, poor abrasion resistance can lead to corrosion points.
In this case, sacrificial coatings can be used to protect pipes and equipment from internal corrosion. Sacrificial coatings or anodic materials, which corrode more readily than the metal substrate of the pipes, effectively prevent metal oxidation. However, existing sacrificial coatings often dissolve too quickly in natural gas pipelines, reducing the effective protection time.
NETL's self-healing cold spray coating technology, which is a high-strength solid coating and powder consolidation process, is suitable for a variety of applications involving metals, metal alloys, and metal composites.
Cold spraying uses high-pressure carrier gas (such as nitrogen or helium) with electric heating to accelerate metal powder through a supersonic nozzle, achieving particle adhesion. In coating applications, cold spraying equipment with a robotic system connected to a pipeline cleaning unit can be used to apply a coating to the interior of the pipe.
Compared to existing methods, some features and advantages of the new zinc-rich coating method include:
Maintain stability regardless of changes in environmental temperature/pressure.
Cold spray deposition does not create defects, thereby extending service life.
When damaged, it self-repairs by forming a protective corrosion product.
No need for regular application (long-lasting lifespan)
Structural material used for repairing/damaged pipes