Fuel reactions

[Irenicus]

Hi dear reader,

I'm a marine engineer and I have a question about my fuel. Our fuel is following the ISO 8217:2010 standard, which speaks of maximum allowance of fuel contamination. Onboard my vessel we're using HFO.

The iso standard says I'm allowed to have up to 300 ppm of Vanadium in my HFO fuel. Now lets take for this example that the standard consumption of fuel is a constant of 100 m³ per week. If I have fuel of 100 ppm does that mean that the damage caused to my engine take 3 times as long as it would for fuel with 300 ppm of Vanadium?

The expected reaction is high temperature corrosion, especially considering that the exhaust line has temperature of 600°C. Take into account that this is a marine engine so high sodium values in the air can be expected. Now I quote: "sodium vanadyl vanadate 5Na2 O. V2O5 . 11 V2 O5 melts at 545 °C. Liquid deposits formed in this way flux the protective oxide layers on structural alloys, making them vulnerable to rapid corrosion." (ref.

http://www.swcc.gov.sa/files\assets...INDUCED HOT CORROSION OF BOILER TUBES....pdf)

A lot of damage can be expected at my piston crown, turbo charger, exhaust seats & valves and exhaust pipelines, therefor this information is interesting to me. Anybody that knows and can explain the answer to my question? Thanks in advance!

 

[mbt22]

If I have fuel of 100 ppm does that mean that the damage caused to my engine take 3 times as long as it would for fuel with 300 ppm of Vanadium?

Short answer, no. The mechanism isn't one unit of vanadium 'takes out' one unit of metal, so the effect will be non-linear.

Matt

 

[bimr]

Corrosion will not be directly proportional to the concentration of Vanadium. Corrosion may increase with higher concentrations of Vanadium, but there is no method available that will accurately predict the corrosion reaction. There are many factors that contribute to corrosion, like engine speed, temperature, environment, etc.

 

[EdStainless]

Temperature is the most important factor for the rate of attack.
What will happen with V is that you will have no attack at some low level.
The at a medium level you will start to see long term degradation.
Then there will be a breakaway point where you will get catastrophic attack.
The 300ppm was set trying to keep you out of the last region.
I would expect this much to show some long term degradation though.
I would think that the engine manufacturers have published lots of research on this subject. After all they use special metallurgy for many parts selected just to fight this issue.

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