Learn About Several Methods Of Painting LNG Gas Storage Tanks In One Article

Learn about several methods of painting LNG gas storage tanks in one article

Painting an LNG gas storage tank may look like putting on clothes for a metal object, but in fact it is competing for time with the low temperature of minus 162 degrees and the corrosion that occurs after being exposed to wind and sun. Inadvertently, the safety of the equipment worth tens of millions and the surrounding environment will become a question.

Don’t fool around with early preparations

Surface treatment is the lifeblood

For gas storage tanks that are exposed to wind and rain outdoors, the rust and sludge attached to the surface must be thoroughly cleaned. When we carried out maintenance work on the No. 3 tank of the Rudong LNG terminal in 2025, workers used high-pressure water guns and sandblasting to remove the old coating and rust. If you are lazy in this step, peeling will occur in just three days after the new paint is applied . After the large tank is riveted and welded, the inner and outer walls are spray-painted for anti-corrosion , causing all the money spent to be wasted. The standard is to reveal the original color of the metal and to have a uniform roughness like fine sandpaper.

Small details hide big hidden dangers

After treating the surface, don't rush to paint. Take a flashlight and shine it inch by inch. Last winter, we wrote an article on an LNG project to learn about several methods of painting LNG gas storage tanks, and found a pinhole-sized pore near the weld of the tank. If you don't repair this kind of place, even painting it won't stop the moisture from getting in. Filling and polishing with special repair material is equivalent to plugging the first corrosion gap in the can.

Choose the right paint to be confident

The anti-corrosion layer must have three lines of defense

The LNG storage tank is not finished with just one layer of paint. It is usually primed with an epoxy zinc-rich primer, in which the zinc powder will protect the steel through self-sacrifice; then epoxy mica is used as a transition in the middle to increase the thickness of the paint film; the outermost layer is a polyurethane topcoat to resist ultraviolet rays and have weather resistance. After such a set of combined operations, the life of the coating can be maintained for more than ten years, which is three times more durable than a single layer of paint.

Being able to withstand low temperatures is no joke

Ordinary paint that is exposed to dozens of degrees below zero is as brittle as a biscuit and will fall off at the slightest touch. LNG storage tanks must use special low-temperature flexible paint. We selected an imported polyurethane modified paint and conducted a bending test in an environment of -165°C. The paint film was intact and had no cracks. If this indicator is not up to standard, once the temperature of the can drops, the coating will collapse and rust.

Construction details determine success or failure

I have to wait for each coat of paint to go through.

The most taboo thing is to be impatient when painting. If you apply the intermediate coat before the base coat is dry, the solvent will be trapped inside, and it will definitely bubble in the future. We have regulations that require at least 24 hours between each coat of paint, and we must use a hygrometer and thermometer to closely monitor the on-site conditions. Last year, the project in Qidong happened to encounter continuous rainy days, so the work was stopped for three days. It was not restarted until the humidity dropped below 80%. The workers were anxious, but the quality should not be anxious.

We need to work harder on blind spots

In places such as the inner and outer corners of the tank and bolted joints, it is easy to miss the mark when spraying, so it is necessary to manually use a brush to reapply it until it is in place. During the inspection in 2024, it was discovered that the back side of the ladder of a certain storage tank was extremely corroded. The reason was found to be that when the painting operation was initially carried out, the paint could not be sprayed evenly here. Since then, we have formulated a rule that all dead spots must be painted twice, and must be inspected and signed by a dedicated person.

Safety and environmental protection cannot be compromised

Workers are armed to the teeth with protection

When spraying operations are in progress, if too much solvent in the paint mist is inhaled, it will cause serious consequences. At the construction site where we are, there is a mandatory requirement, which is to be equipped with air-supplied respirators and anti-static work clothes, and. And a gas detector should be equipped on site. Once the concentration of volatile gases exceeds the standard, it will immediately sound an alarm. Among the newly introduced regulations this year, an additional requirement has been added, that is, if the spraying operation is continued for two hours, the personnel must be replaced to take a break. After all, safety is more important and valuable than the progress of spraying paint on the inner and outer walls of large tanks to prevent corrosion after riveting and welding .

Waste disposal must comply with regulations

The paint residue and used paint buckets are all hazardous waste. We have signed a contract with a local qualified processing company. Each batch of waste must be weighed, labeled, and the transfer slip must be retained. In the past two years, a company secretly buried paint residue in order to save trouble. As a result, it was discovered and fined 500,000 yuan. It was really a waste that outweighed the gain.

Later maintenance depends on carefulness

Don’t forget regular physical examinations

Just because the paint is painted doesn't mean everything will be fine from now on. Shelves need to be built every six months so that you can go up and check them out. It is important to check the top of the tank and the surface exposed to direct sunlight, because these areas age most rapidly. We choose to use a thickness gauge to randomly measure the thickness of the paint film, and then compare it with the original data. If the loss exceeds 20%, local repair work must be arranged to eliminate minor problems in their infancy.

Small damages will be repaired on the same day

Once you notice scratches caused by metal exposure, touch-up paint must be carried out within 24 hours. We prepare portable tanks of the same color and spray paint. After riveting and welding the large tanks, the inner and outer walls are spray painted to prevent corrosion . Any damage will be repaired immediately. During the typhoon last year, a billboard hit the tank, and a palm-sized piece of paint was wiped off. As soon as the typhoon stopped, personnel were sent to repair it, leaving no chance for the rust to take advantage of.

The protective device of the storage tank containing LNG starts from the selection of materials, to construction, and to subsequent maintenance. No matter which link you dare to be careless about, if there is any oversight, you will have to repay the consequences multiple times in the future. How long has it been since the last time you carefully inspected the water tank on the roof of your residential complex for rust and corrosion?