Tank Pickling and Passivation

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Tank / System (BD tank) Pickling and Passivation

Tank/ system pickling is carried out to remove metal surface impurities like iron oxides, rust, or stain to ensure the surface is rust-free and smooth. This is particularly important and crucial for butadiene (BD) tank storage and pipelines, where the presence of rust, oxygen and water will end up with formation of butadiene polymer, or commonly known as ‘popcorn’. This phenomenon is highly not desired, as the popcorn formation will be in propagation mode once it started and might resulting in occupying the full space and rupture the structure or piping, leading to BD leakages and other unwanted incidents.

Besides, pickling help to remove the surface dirt and rust, leaving the metal surface clean and smooth for passivation to take place. Passivation is a procedure to form a thin film layer of protection to the metal surface, making it more resistant to corrosion. Therefore, it is always good to couple both pickling and passivation process for the best code of practice

Why pickling and passivation?

Remove impurities on the metal surface (Pickling)

Protect metal surface and integrity (Passivation)

Increase the durability of the metal tank, prolong service life span of storage tanks (Pickling and Passivation)

Pickling and passivation process involve circulating the pickling solution followed by passivation solution, covering the metal surface thoroughly for a period time. This can be done by full pipe circulation (for pipelines) or by spray nozzles (for storage tanks).

For pickling and passivation on storage tanks, where using spray nozzles is more practical and economical, the pickling and passivation process must be carefully designed. This includes the right selection of spray nozzles, circulation pumps, circulation tank volume etc. The process designed has to ensure sufficient volume for circulation and the spray nozzles are able to cover the whole surface area.

With the joint effort of our engineers, technical, as well as QA team, we have established own operating procedure, testing method to ensure safe and effective pickling and passivation process. However, the circulation system is customised on case-by-case basis, as the pickling and passivation volume required, the type of spray nozzles, circulation volume etc are differ from each other depending on the tank shape/ volume/ pipe size/ distance.

Our qualified engineers are well verse in evaluating the surface/ dimension of the area to be pickled and passivated, and then design a customised pickling and passivation system by selecting the right spraying nozzles, circulation tank and pumps. We can carry out pickling and passivation on horizontal storage tank, ISO tanker or big spherical storage tank.