diesel fuel storage??

[cadye]

If my diesel tank was topped up before storage last fall, did not launch this year, should I be doing something with the fuel to make sure it does not go bad? Is there a stabilizer or something that can be added?
Newbie just wondering.

[captain323]

Here is a link from the library of Don Casey(boatus.com) that describes Fuel System maintenance. I hope you find this helpful.

http://www.boatus.com/boattech/casey/33.htm

[Alan Wheeler]

Unlike Petrol (gasoline) Deisel does not go stail. So wintering over with a tank of Deisel is not a problem from the fuel quality perspective. What is a problem is water in the tank. This can come from several sources, being condensation, poor sealing of your own fittings and pumping into your tanks from a poor shore storage facility. I should add here, if poor storage facilities is common problem in your area, a pre-tank entry filter is a good recomendation. Filter the fuel before it enters your tanks. But thats an aside. Good onboard tank design can help. I like seeing a tank that has a shape to the bottom of it, where water (being heavier than fuel) will settle to a common point in the tank. At that point, a valve should be fitted, so bleeding off any settled out water, is a breeze. No water, no poroblems. It's as simple as that. Then just to be sure, pour in a deisel fuel additive that deals with fuel algee I personally use an additive called Fuel set. The only reason is that it mixes with the water and turns it white. When water does enter the fuel system, it settles to the bottom of my water seperator and I can easily see it. A quick drain off and I am back in business. The additive ensures no algee growth and should in the accidental event, that water is picked up, this additive is "supposed" to allow it to be burnt. I don't recommend that, as I don't trust water through injectors, but it is a last chance back up just incase.

[delmarrey]

I don't know how much fuel you store but one thing I do is every spring is run my whole tank thru a filtering system into a barrel and then thru a filter back into the tank.

I built my own set up but there are companies out there that do dockside filtering with portable units, for a fee of course.

The big problem with diesel, which you don’t get with gasoline, is the sludge's that settle in the tank.
And like Alan was saying water is another problem. The object is to keep the fuel tank warmer then the out side air, up to 65 degrees. On a warm humid day a colder tank will suck in the moisture and settle on the inside surface. Then it'll drip and run to the bottom of the tank. A full tank helps cover the surfaces but it would, just about, have to be running out the vent tube.

And biodiesel is a bigger problem. These last few months I've had to change fuel filters in our biodiesel dispensers about every 2-3 weeks. There is so much demand for it right now that the quality has gone down. The fuel sites are running a 10 micron filter while the equipment is running a 5 micron.

Antimicrobial additives help keep down the bacteria when water starts to build up but stabilizers I'm not sure do anything. Diesel doesn't evaporate as fast as gasoline.

My $.02

[irwinsailor]

The fuel that was in my boat when I bought it was over 3 years old. I replaced the engine and was concerned about running old fuel through it. Many told me to get it pumped out and get new fuel. I looked at the fuel and it looked and smelled good to me (and being a cheap sailor) I ran it. There was no problem. I later found out if the fuel is clear and clean there is no issue using it. In my case it was about 200 gallons.

[Alan Wheeler]

Delmarrey, the "sludge that settles to the bottom" could be that you need to get your tanks cleaned, OR, that you have contaminated fuel going in or something. Good clean Deisel will not go sludgey. Although!!! there is one thing that does happen to Deisel in some area's of the world. Some parts of the world that have hot summers and very cold winters will have additives added to the winter fuels. This stops a wax from forming which looks like a sludge. In the summer, the fuel companies often don't add the additive. If you have summer fuel in your tank and it gets real cold, then maybe you are experiancing a wax forming in the fuel.

[delmarrey]

Here is a posting that might be of interst to all. Obviously, they are trying to sell their product. But what they have to say, I've experienced in our fleet and fuel sites. Although, we are running Biodiesel now the problems have become much worst.

diesel fuel

[ssullivan]

Del,

Going by your suggestion, is it safe to assume that a liveaboard in the winter wouldn't need to do anything speical to his stored diesel, given that he is aboard 24/7 and heating the boat?

Also, based on your suggestion, it would seem the worst condensation will happen in the spring, as warm, humid air settles in during the day with cold, chilly nights. That could make for a much colder tank sucking in the humidity from outside. Am I understanding this correctly?

delmarrey once whispered in the wind:
. The object is to keep the fuel tank warmer then the out side air, up to 65 degrees. On a warm humid day a colder tank will suck in the moisture and settle on the inside surface. Then it'll drip and run to the bottom of the tank.

My $.02

[delmarrey]

Basically that's it, keep the fuel tank warmer then the outside and the condensation will not enter. Spring or winter, whatever the highest humidity will be the highest chance.

Mine sits on the hard most of the time, so in the cooler months I keep heat lamps pointed at my engine and fuel tank to keep'm dry. As well as keeping the inside of the boat dry.

It kinda ironic but moisture (and birds) is a boats worst enemy when in storage. As the ole saying goes "use it or loose it"

For the most part Boats are not like trucks. Trucks have their fuel tanks on the outside exposed the elements. So when it gets cold one needs to put in additives to compensate for the cold running.

Boats on the other hand have their tanks on the inside keeping them fairly warm. So an additive for the cold is not necessary, that's unless it's a ship or steel hull with the tank as part of the structure. Then the 28- degree water will chill the fuel.
I have at least 1" of space all the way around my tank keeping the temp. even through out. Plus, I filter it every spring just for GP (general purposes).

If you’re a live aboard just keep the warm air circulating around the tank. Using an 110V (quite) computer fan and a couple vent holes would work great while in port.
.................................................. ................_/)

[Steve Kidson]

Easiest way to minimise condensation (water) inside tank is to keep tanks as full as possible. This is not always practical, but if leaving boat laid up for any period of time, fill tanks from a reputable and reliable source prior to shutting up.

Steve

[Richhh]

1. Diesel fuel most definitely has a relatively short 'shelf life'. 6 months is about the longest storage term if the fuel is near 30 degrees C. After 6 months, fuel oil begins to polymerize, begins to 'drop out' some fractions and also volitizes the lighter fractions (out the vent). Particles then begin to agglomerate (into larger and larger particles) and begin to adhere on the tank walls.
Any copper in the system (delivery tubing, fittings, etc.) will accelerate the decomposition process.

2. Stabilizers are beneficial but do not protect from all forms of decomposition.

3. DO NOT KEEP A FULL TANK.
I personally only fill the tank with what I need in the immediate future plus a small reserve for emergencies. For long term storage I have as little fuel in the tank as possible (I take the stuff home and burn it in my home oil burner in wintertime). To prevent all the inevitable condensation problems during winter storage I apply a 'packed column' of silica gel to the tank vent line. The silica gel is a regenerable desiccant that adsorbs moisture (and oil vapor) from the vent .... if not oil fouled can be regenerated in an oven for 6 hours at 300 degrees. I also add some 'colored silica gel' to the 'column' and when it turns from blue to pink I know I need to regenerate. The column is just a simple 4" dia pc. of semi-clear plastic pipe with 1/2" HB connections on the end, with a screen to prevent the si-gel from coming out when I dont want it. I leave it inplace in the vent line all year long. I have absolutely NO water contamination in my fuel.

If anyone wants a schematic of the (somewhat elaborate) fuel system. Contact me at: RhmpL33ATattDOTnet and Ill send you a .pdf

[Alan Wheeler]

I new we had a much better grade of fule here in NZ. But wow, after reading the link and seeing the comments. We just don't have issues of fuel storage here. The fuel remains clear and I have never seen it "Polymorf". The only iusses I have ever seen is when water is present and algae grows. Then it is a compleate mess.

[ssullivan]

Wheels,

I read recently that our diesel in the States is definitely of a lower grade that most. I think I was looking at a website concerning high performance diesel cars from Europe.

They don't run as well here due to our lower grade diesel. This is one factor preventing the manufacturers from selling them here. I don't know what (if anything) that has to do with the
fuel's stability over time, but you are probably correct in saying NZ has better fuel.

Alan Wheeler once whispered in the wind:
I new we had a much better grade of fule here in NZ. But wow, after reading the link and seeing the comments. We just don't have issues of fuel storage here. The fuel remains clear and I have never seen it "Polymorf". The only iusses I have ever seen is when water is present and algae grows. Then it is a compleate mess.

The price of cleaner air...
I saw the mention of algaesides earlier in the post. If the tank is clean, it probably is not a problem, but if algaecide is used in a tank that has algae in it, it will kill the algae, but leave a brown sludge that is guaranteed to plug filters faster than you can replace them. Fuel polishing is a good way to solve problems. The 55 ga drum idea is another good one. A 5 gallon day tank in the system is a very good idea, and my whole system on the trimaran is based on 5 ga jerry cans with a thread on pick-up at the cap. I have not put it in service yet, but I have high hopes that it wil perform well.
As for keeping the tanks empty, either empty or full is good, but nothing in between. Full tanks will not allow space for condensation, and dry tanks obviously do not have any water to cause rust.
Richh is correct about the 6 months life, but that is based on lab quality tolerances. The engine will run fine on 2 or 3 year old diesel.
The bottom line is, the best idea is not to let it sit, but if you do, keep it clean and keep it dry.

[Richhh]

Not so Kai,

If the vent is open to atmosphere and no matter how much free volume is exposed to air, chemical equilibrium will dictate that water vapor will combine with the fuel, and despite thermal stability of the fuel. Even sealed electrical power transformers will 'transpire' water vapor into the oil.

The BP/Australia website has a good treatise on diesel fuel shelf life and storage requirements. Its written for the non-technical user but still very informative. Dont have the URL at hand, sorry; but, the following link will get you started: http://www.bp.com.au/fuelnews/ADF1402.pdf

My professional activies include this sort of thing so I naturally gravitated to a 'gizmo' to prevent water uptake .... a desiccant trap on the vent. Not only does the fuel have fraaction drop-outs and volitization but certain microorganisms use the oil as a nutrient source (also the metal tank walls as a nutrient source - in the presence of free or emulsified water) ... so the vent trap blocks aspiration of these microorganisms as well as the constant ingress of water vapor. Many of the the dead micro cells become 'growth sites' for the polymerizing particles to 'grow'/agglomerate. I use a teflonic membrane to block aspiration of microorganisms to my potable tank water and am considering to add a bacterial blocking vent filter to ensure total exclusion of same to the fuel oil.

hope this helps.