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Factors behind fuel tank lid corrosion

Corrosion in fuel tank lids can be a major issue and so we were determined to help when we received these pictures from a customer of ours in Bahrain.

In recent years rampant corrosion has been discovered in fuel tanks and, as we discussed with our customer, there can be multiple factors at play.

In this instance the warm, humid and saline climate of Bahrain may be more of an issue than it would be in, for example, the UK.

In addition you are more likely to find grains of sand on the boots of an engineer in the Middle East than you would over here.

With these tank lids protected inside manways that people stand in, those grains of sand can find their way into the protective surface coatings whilst engineers work on installing the components. Minute scratches can in turn cause potential weak areas for corrosion to take hold.

But in addition, the chemistry of new fuels has also been shown to be a factor behind fuel tank corrosion, as outlined in this article from Petrol Plaza.

When moisture vapour and hydrocarbon vapour are mixed, microbial growth can cause acetic acid to be formed. With E10 mixed gasoline now the norm, this is increasingly becoming an issue.

As Alan Kelsky outlines, E10 refers to the fact it is 10% ethanol. Ethanol molecules are hygroscopic, meaning they attract and absorb water – although ethanol on its own is not corrosive, its hygroscopic nature is key to the problem of fuel system corrosion.

As ethanol attracts and holds water, it is the perfect medium for growing a bacterium known as Acetobacter in the fuel tank. One by-product from Acetobacter is acetic acid, which causes corrosion within the fuel system.

We were quick to explain to our Bahraini customers that these factors could be behind the increased corrosion they are seeing.

We have also pointed them in the direction of products available that extract both moisture and hydrocarbons from the atmosphere. Alternatively keeping them in a tank chamber could also have a big impact in reducing the potential for corrosion.

If you are having issues with fuel tank lid corrosion, please don’t hesitate to contact Risbridger along with any pictures. We would be delighted to assess the problem and suggest viable solutions.