An invention reported by researchers from NETL can help protect against corrosion in natural gas, hydrogen, and carbon dioxide (CO₂) pipelines. Pipeline corrosion can cause catastrophic failure events such as explosions and emissions of environmentally damaging substances like methane.

The innovation is a new self-healing cold spray coating for internal pipeline corrosion protection.

According to NETL’s Ömer Doğan, who worked on the innovation with NETL researchers Joseph Tylczak, and Margaret Ziomek-Moroz, and Zineb Belarbi, internal pipeline corrosion is a common problem.

“Internal corrosion in pipelines primarily is due to the presence of water, carbon dioxide, and hydrogen sulfide contained in natural gas,” Doğan explained. “Internal corrosion can eventually result in leakage, cracks, and rupture of the pipeline leading to explosion hazards and methane emissions.”

Traditional approaches to fighting pipeline corrosion included use of inhibitors or organic coatings such as fusion-bonded epoxy and polyurethane. Injection of inhibitors in natural gas or CO₂ pipelines is challenging because of the difficulty of transporting the inhibitor along the pipelines. The main disadvantage of using organic coatings for internal pipeline protection is that they have poor abrasion resistance and can form a corrosion focal point.

Doğan said another approach is to use sacrificial coatings to protect pipelines and equipment from internal corrosion. A sacrificial coating, or anode, undergoes oxidation more than the metal surface it protects, effectively stopping oxidation on the metal. However, the existing sacrificial coatings 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,” Doğan said. ‘This new material can be applied to steel structures in a cold spray process to protect them from the effects of corrosion.”

Cold spray is a high-energy solid-state coating and powder consolidation process for application of metals, metal alloys, and metal blends for numerous applications. Cold spray uses an electrically heated high-pressure carrier gas, like nitrogen or helium, to accelerate metal powders through a supersonic nozzle for particle adhesion. The coating can be applied to the interior of a pipeline by using a robotic cold spray device attached to a pipeline pig.

Just some of the features and advantages of the new zinc-rich coating approach compared to existing approaches include its ability to:

• Remain stable regardless of temperature/pressure changes of the service environment.
• Not form defects during cold spray deposition resulting in its extended life.
• Self-heal when damaged by forming protective corrosion products.
• Not require a periodic application (long life).
• Be used as structural material to repair used/damaged pipeline.

A Report of Invention (ROI) was disclosed June 30, 2023, and assigned 23N-12. 

NETL is a U.S. Department of Energy national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By using its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.