Corrosion: A Very Asian Preoccupation

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For firms which are using floating production, storage and offloading (FPSO) vessels, one of the biggest and most costly issues they have to deal with centres around the issue of corrosion management and how to deal with it most effectively.

It is a particular worry for firms which operate production services in Asia and this is the case simply because of the fact that the climate and conditions in Asia are the most favourable for the corrosion of metals.

Speaking ahead of the14th Middle East Corrosion Conference and Exhibition in Bahrain, the country's minister for energy Dr Abdul Hussain bin Ali Mirza said that high humidity, continuously high temperatures (particularly in summer), and high salinity were very conducive to the corrosion of metals.

He went on to say that once firms can get to grips with the costs of dealing with the corrosion of metals, they will see billions of dollars saved every year.

However, according Hilman Mohammed Saleh, corrosion and integrity engineer for corrosion management and inspection framework for topsides at BW Offshore: "It can very often be the case that the most effective products to deal with the corrosion of metals are either far too expensive to be financially viable, or are simply not available in this part of the world."

"There needs to be a balance and compromise when it comes to material selection," he said.

He also added that it was important when starting the building of a vessel to consider longer term solutions than have possibly been dealt with in the past. Because there is a growing appetite for retro-fitting thanks to the fact that there are extensions in projects, firms will be looking to repair corrosion. He said it would be more cost-effective in the long term to simply look at finding more long-lasting solutions in the first place.

"Often, materials are chosen that will satisfy the required life cycle of the unit. However, these days more life extension projects of existing units are on-going. Therefore, new design should look into a longer life cycle than the typical 15 – 20 years".

Another problem which can exist deals more specifically with the retrofitting of measures to deal with corrosion, or replacing of parts which have outlived their lifespan.

When a ship is being built, cathodic treatment and coating of pieces of a vessel which have yet to be fitted together can be an easy task. However, for firms in Asia it can be particularly problematic to deal with the treatment of a full-scale hull on a vessel which is already in use.

The first line of defence against corrosion on any ship, according to Stop Rust, is the coating which is applied to the hull, while any areas which have defective coating, or perhaps where coating has worn out, will need to be protected by cathodic protection systems.

Because of the fact that regular ocean-going vessels are required to come into dock at five-year intervals, it should theoretically be easy enough to deal with areas which need retreated. However, according to Offshore Magazine, those operating in Asia will find the problem that most sites dealing with corrosion management are found in Singapore, and these often simply do not have the capacity to deal with the scale of the job with regards to a full ship.

The retreatment issue is exacerbated with FPSOs, because of the fact that they can be offshore for more than 15 years at a time. This means that it is vital to ensure that cathodic protection systems are both strong and up-to-date, as well as ensuring that anti-corrosion coating is the best available.

Therefore, the main issues which need to be dealt with in an environment where corrosion is likely to be commonplace centre around ensuring that the price of doing so can be dealt with effectively, as well as making it easier for firms to be able to deal with retrofitting of measures to control the corroding of their equipment.