Diesel Fuel Treatment

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Snipe
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Diesel Fuel Treatment

Post by Snipe »

I'm in a situation that has a potential for fuel problems, and I could use some real world, impartial advice...

I just got on a vessel that has been permanently moored dockside for 7 years. We stay on shore power unless the lights go out, which has been very rare, so the generators run very little. The emergency generator runs two hours a month for required testing, the main engines for slight shifting to tighten mooring lines occasionally. All engines are 149 Series Detroit Diesel; E-gen is a Detroit 6V92.

The boat hasn't fueled since August 2005. Out of a 16,000 gallon capacity, we're currently down to 6300 gallons.

The fuel has never been treated with any kind of chemical for microbial/algae growth, water, etc. The engines all run great, fuel looks clear, it is #2 diesel.

I want to get this fuel treated to avoid future trouble. Can you guys recommend a particular product for this situation?
Should I top off the fuel I've got now with fresh stuff and then treat the whole batch, or can I treat the existing 6300 gallons with a product and call it good?

I've looked at a few fuel treatment vendor websites and they all seem to be like snake oil salesmen. I don't want to add a particular product that would make things worse; that's my biggest concern right now.

Any insight you people can give will be appreciated!

Thanks...
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The Dieselduck
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Re: Diesel Fuel Treatment

Post by The Dieselduck »

Great question,

I am not sure what kind of treatment you have in mind, but the first thing I would do is find out if you have indeed a bug problem. If you don't, then there is no real need to panic and go on treating with "snake oils", magnets or other voodoo crap. If you do choose to treat with a biocide, I would recommend biocide products from standard chemical companies, such as Nalfleet, Drew, Unitor and such, they all have suitable products, so as to bypass the overinflated salespeople and their claims.

I am not sure what kind of degradation occurs in diesel over 7 years, but I suspect its not a huge impact if you don't have water in it. If you do have bugs then its a pretty big problem. Then you will have to add biocide, and then filter the garbage out (dead bugs - black slimmy goo). This can be done burning it, having lots of spare filters around, or using a "fuel polishing" services.

Either way I would not bunker on top of that fuel, seems to me you have some flexibility, judging you've been tied up up for 7 years - and still care about the boat, so the first step would be to find out if you actually have bugs growing in it. For this you can use Hum Bug type test kits, relatively cheap and common. http://www.hammondscos.com/products_off ... ctor%20Kit

After that if you are still worried you could try sending samples to fuel testing labs for a more definitive outlook, definitely cheaper than getting rid of 7000 gal of diesel, or a set of injectors.

Here's more on diese from Wikipedia... (http://en.wikipedia.org/wiki/Diesel)

There has been much discussion and misinformation about algae in diesel fuel. Algae require sunlight to live and grow. As there is no sunlight in a closed fuel tank, no algae can survive there. However, some microbes can survive there, and can feed on the diesel fuel.

These microbes form a colony that lives at the fuel/water interface. They grow quite rapidly in warmer temperatures. They can even grow in cold weather when fuel tank heaters are installed. Parts of the colony can break off and clog the fuel lines and fuel filters.

It is possible to either kill this growth with a biocide treatment, or eliminate the water, a necessary component of microbial life. There are a number of biocides on the market, which must be handled very carefully. If a biocide is used, it must be added every time a tank is refilled until the problem is fully resolved.

Biocides attack the cell wall of microbes resulting in lysis, the death of a cell by bursting. The dead cells then gather on the bottom of the fuel tanks and form a sludge, filter clogging will continue after biocide treatment until the sludge has abated.

Given the right conditions microbes will repopulate the tanks and re-treatment with biocides will then be necessary. With repetitive biocide treatments microbes can then form resistance to a particular brand. Trying another brand may resolve this.


Basically keep all water out of your tanks.
Martin Leduc
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Martin's Marine Engineering Page
http://www.dieselduck.net
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JK
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Re: Diesel Fuel Treatment

Post by JK »

I agree, test.
Don't add bug killer if you already have contaminated fuel.
If you have bugs, you can try calling a tank cleaning company and see if you can swing a deal for tank cleaning for fuel. Make sure the cleaning water is Hot, 70*c . Then treat the tank with Aderco to prevent a water \fuel interface.
I personally don't like bug killer additives because you always seem to have your hands in diesel.

I am going to add, with the boat permanently moored, this is probably not going to be an immediate problem. The tank is not being agitated and any bugs being circulated. Keep the water drained from the tank and watch for a jelly like substance. As the fuel level drops you will have to address the problem(if there is any). Do not circulate from an infected tank to another. When you fuel again, just take enough for immediate needs, especially if the boat is not moving anywhere.
Treat with the Aderco, we have had good luck with the product. A 1L bottle will treat 5000L and has the added benefit of the fuel burning more completely on injection, which leads to a cleaner engine at disassembly time.
Do not assume you are getting clean fuel from the supplier, they have done a nice job of contaminating our ships in the past.

If it seems outrageous trading fuel for tank cleaning, just calculate the cost of the tank cleaning, the cost of fuel filters and injectors and add in the engineer's time. Then add in the time to take apart fuel lines in the engineroom to clean them in a really bad contamination problem. Then add in the PITA factor of your Operational personnel screaming to get the ship into service.
Of course, this is IMHO.
Snipe
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Re: Diesel Fuel Treatment

Post by Snipe »

Thanks, guys, good advice. A local lab is going to perform a test for us to check for moisture, microbes, and stability for $125. Then we'll go from there...
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JK
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Re: Diesel Fuel Treatment

Post by JK »

I would be very interested in how you make out with this. Let us know and best of luck.
Snipe
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Re: Diesel Fuel Treatment

Post by Snipe »

Finally got our fuel test report back. Amazingly, everything is within specs. No water, bacteria, fungi or mold. The only borderline item was the cetane number, it is 40.7, whereas 40 is considered the minimum. All other items like flash point, sulfur, etc. were well within limits.

Apparently the conditions in our fuel tanks are ideal for fuel storage...
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JK
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Re: Diesel Fuel Treatment

Post by JK »

Amazing!!
Now, if you were getting the ship ready for sea, I can guarantee a different story and the contamination levels would be proportional to how quickly you had to get it up and running.
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