Corrosion Under Insulation in an Aging Plant

Hot and Humid

Established in 1989, NLNG, an LNG facility in Nigeria, currently has six Trains, with tray seven due to be added shortly. The plant has a total production capacity of 22 Million Tons Per Annum (mtpa) of LNG and 5mtpa of Natural Gas Liquids (NGLs), which equals 6% of the global market.

Located in a hot, humid, and very salty environment, piping and vessels at this facility are prone to corrosion. Various kinds of paint and insulation have initially been used for corrosion protection. After 20 years in service, Corrosion Under Insulation (CUI) has turned into a significant problem with many pipes about to burst. Ignoring the problem or an insufficient solution could result in fire, explosion, environmental damage, loss of life, loss of profit, or production loss.

PROBLEM

Located in a hot, humid, and very salty environment, vessels and piping at this facility are prone to corrosion. After 20 years in service, Corrosion Under Insulation (CUI) has turned into a significant problem with many pipes about to burst.

 

SOLUTION

Thermal Spray Aluminium (TSA) is an optimum solution due to a long inspection cycle, >20 years, and proven reliability. IGS TUFFss ONLINE TSA technology was safely applied during plant’s operation.

CUI Problem: Evaluating Alternatives

Repainting the piping with the same or similar paints and coatings that have already failed once was one of the options being considered. Some new technology paints and coatings were also being looked at. These paints would still need to be inspected and usually reapplied every 5-10 years. Thermal Spray Aluminium (TSA) was an optimum solution due to its long inspection cycle, >20 years, and proven reliability.

CUI
After_TSA_Exchager_1b

Online TSA Application in 2016-18

The scope included a 50-meter (160 foot) column and a two-level platform with two heat exchangers/reboilers. IGS TUFFss ONLINE TSA was applied to a total area of 700m² on cold and hot surfaces.

This onsite project began on October 1st 2016, and concluded in January 2018. The project was carried out in adverse weather conditions, including heavy rain, thunder, sandstorms, high temperature, and high humidity.

Why IGS TUFFss Online TSA?

Traditional TSA coatings would not be practical in this case. The scale of the work in total to be completed exceeded 360000m2. Applied during turnarounds, it would have taken over 30 years to protect all corroded piping and vessels. The plant would not have lasted 30 years in its present condition! The plant, therefore, needed a TSA technology that could be applied while the plant is live.

Project Completion and Future Maintenance

This project succeeded in meeting and exceeding all objectives by rigidly following all safety guidelines. The project utilized specially designed Habitats to enable weather protection, climate, humidity, and pressure control. It was now confirmed without a doubt that it is possible to do the encapsulated TSA maintenance in a live environment, which will be of great importance to them in the future as the work continues on the remaining six trains.

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Energy
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Thermal spray