How long should diesel be kept before adding a conditioner? Are they really necessary? Is ambient temp relevant the "life" of fuel? Which ones are the best? Cheers.
Diesel conditioners
- Thread starter Mybigblue
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Given the way fuel is generally allowed to sit on a sailboat, often for months at a time, I would recommend using a conditioner whenever you add fuel.
Julie—
I hope you had your fuel tank inspected and cleaned if necessary, otherwise spending the money on polishing the fuel may be a waste of money.
Also, I hope there's no water in your diesel fuel tank, as that is the primary cause of fuel needing to be polished.
Julie—
I hope you had your fuel tank inspected and cleaned if necessary, otherwise spending the money on polishing the fuel may be a waste of money.
Also, I hope there's no water in your diesel fuel tank, as that is the primary cause of fuel needing to be polished.
I would use sparingly if at all. Never used it on my Catalina and put 5k hours on it. If you buy fuel that is filtered and moves and you filter are check and changed, there is no need for conditioners. Sta-Bil for storage excepted. Excessive use of them harm the injectors spray pattern.
If you go thorugh fuel on a regular basis there's less of a need than if it sits for extended periods of time. I've seen problems on other peoples boats as well as a delivery I was doing so I always use an additive. A bottle of it goes a long way and is cheap insurance.
Not that this clears everything up but here is what one refinery has to say - additive discussion at end:
FUEL NEWS
LONG TERM STORAGE OF DIESEL
Issued : February 7, 2002 ADF1402
BP Australia Limited
A.C.N. 004 085 616
Marketing Technical Services
STORAGE LIFE
Under normal storage conditions diesel fuel can be expected to stay in a useable condition for:
• 12 months or longer at an ambient of 20ºC.
• 6-12 months at an ambient temperature higher than 30ºC.
As diesel gets older a fine sediment and gum forms in the diesel brought about by the reaction of diesel components with oxygen from the air. The fine sediment and gum will block fuel filters, leading to fuel starvation and the engine stopping. Frequent filter changes are then required to keep the engine going. The gums and sediments do not burn in the engine very well and can lead to carbon and soot deposits on injectors and other combustion surfaces.
The expected life of a diesel fuel is indicated by the oxidation stability test ASTM D2276. The test measures how much gum and sediment will be deposited after keeping the fuel at 120°C in the presence of oxygen for 16 hours. It roughly corresponds to one year storage at 25°C. A result of less than 20mg/L of sediment and gum after the test is considered acceptable for normal diesel.
PROLONGING THE STORAGE LIFE
Prolonging the storage life is achieved by removing or controlling the conditions described in the previous section. Important measures to take are as follows:
Issued : February 7, 2002 ADF1402
Supersedes : February 14, 2000 Page 2 of 3
BP Australia Limited
A.C.N. 004 085 616
Marketing Technical Services
• Ensure that the fuel is not in contact with any surfaces containing zinc or copper or compounds containing those metals (eg. brass). If those metals are present then a metal deactivator additive may help.
• Establish a regular fuel maintenance program to ensure that water and dirt is removed from storage tanks. This will also remove any chance for fungus to grow.
• Water should be drained from the storage tanks weekly. The frequency can be extended if the tank shows no tendency to collect water but should be done at least monthly.
• Tanks should be kept full to reduce the space for water to condense, maintaining tanks half full increases the water build up and promotes corrosion in the top half of the tank. Most water will come from condensation as the tank breathes, the rate at which water collects will depend on local climate and will be higher in hot humid coastal areas.
• Tanks should have a well defined low point where water will collect and can be drained. For example, cone down bottoms.
• Establish a system for filtering the contents of the main storage tank through a recirculating filter system. This can be made automatic and will reduce the potential for problems by removing sediment and gums. The filters should be checked and changed at regular intervals. When the filter change interval reaches a certain frequency then the fuel should be changed over.
• Tanks should be emptied and cleaned at least once every 10 years, or more frequently if there is a major contamination.
• Ensure that the fuel supplied conforms to a recognised specification, in Australia that would be AS3570, and ensure the fuel matches the winter cloud point for the area to avoid filter blocking by wax drop out in cold weather. .
• Always purchase fuel to replenish stocks in the winter season April - August. This will ensure that the fuel will not cause wax problems whatever season it is used.
• Obtain assurances from the supplier that all components are fully refined to promote stability.
• Establish a monitoring program whereby samples are taken at regular intervals to monitor the condition of the fuel. The samples can be examined at the site visually for evidence of haziness, sediment, darkening or sent to a laboratory for testing.
• Regularly turn the fuel over. If possible, plan the fuel usage so that it will all be used within 1-5 years and replaced with fresh fuel.
ADDITIVES TO IMPROVE STORAGE LIFE
The following additives can improve fuel storage life:
Issued : February 7, 2002 ADF1402
Supersedes : February 14, 2000 Page 3 of 3
BP Australia Limited
A.C.N. 004 085 616
Marketing Technical Services
• Metal deactivators. These work by stopping copper, zinc and other reactive metals from reacting with the fuel.
• Fungicides/Biocides. These work by stopping fungus and bacteria from growing in the fuel and so prolong the life of the fuel. They are only effective on fungus and bacteria and will not stop other oxidation reactions from taking place. They are normally active at the water fuel interface where the fungus and bacteria grow. If fungus is present then a kill dose is required. Otherwise a maintenance dose is used to stop fungus growing. The disadvantages of biocides are:
• handling and mixing is hazardous because they are poisons.
• for a kill dose, killing the fungus can lead to a build up of dead matter which will block filters and also cause the fuel to oxidise.
• ideally, the fungus should be killed and then the tank emptied and drained out.
• maintenance doses are effective but no more so than regular water draining.
• disposal of water bottoms requires special handling with due regard to the environment.
• Anti-Oxidants. These work by stopping the oxidation processes from taking place. They prevent the fuel oxidising and reduce the formation of sediment and gum.
• Fuel Stability Foam. FuelKleenik is a stability foam which is suspended in the diesel fuel in the tank. It has been developed and tested by Department of Defence and is claimed to keep the fuel stable for up to 10 years. The disadvantages are:
• it does not work where fungus and water are present which is why it is suspended in the fuel.
• its size is 2100mm x 200mm x 200mm so it has to be dropped in through a hatch.
After 15 years it has to be disposed of to landfill.
FuelKleenik is available from a company called FuelTreat ph 1800 034442 .
For further information, please call the
BP Lubricants and Fuels Technical Helpline
1800 033 558
freecall
or visit www.bp.com.au/fuelnews
FUEL NEWS
LONG TERM STORAGE OF DIESEL
Issued : February 7, 2002 ADF1402
BP Australia Limited
A.C.N. 004 085 616
Marketing Technical Services
STORAGE LIFE
Under normal storage conditions diesel fuel can be expected to stay in a useable condition for:
• 12 months or longer at an ambient of 20ºC.
• 6-12 months at an ambient temperature higher than 30ºC.
As diesel gets older a fine sediment and gum forms in the diesel brought about by the reaction of diesel components with oxygen from the air. The fine sediment and gum will block fuel filters, leading to fuel starvation and the engine stopping. Frequent filter changes are then required to keep the engine going. The gums and sediments do not burn in the engine very well and can lead to carbon and soot deposits on injectors and other combustion surfaces.
The expected life of a diesel fuel is indicated by the oxidation stability test ASTM D2276. The test measures how much gum and sediment will be deposited after keeping the fuel at 120°C in the presence of oxygen for 16 hours. It roughly corresponds to one year storage at 25°C. A result of less than 20mg/L of sediment and gum after the test is considered acceptable for normal diesel.
PROLONGING THE STORAGE LIFE
Prolonging the storage life is achieved by removing or controlling the conditions described in the previous section. Important measures to take are as follows:
Issued : February 7, 2002 ADF1402
Supersedes : February 14, 2000 Page 2 of 3
BP Australia Limited
A.C.N. 004 085 616
Marketing Technical Services
• Ensure that the fuel is not in contact with any surfaces containing zinc or copper or compounds containing those metals (eg. brass). If those metals are present then a metal deactivator additive may help.
• Establish a regular fuel maintenance program to ensure that water and dirt is removed from storage tanks. This will also remove any chance for fungus to grow.
• Water should be drained from the storage tanks weekly. The frequency can be extended if the tank shows no tendency to collect water but should be done at least monthly.
• Tanks should be kept full to reduce the space for water to condense, maintaining tanks half full increases the water build up and promotes corrosion in the top half of the tank. Most water will come from condensation as the tank breathes, the rate at which water collects will depend on local climate and will be higher in hot humid coastal areas.
• Tanks should have a well defined low point where water will collect and can be drained. For example, cone down bottoms.
• Establish a system for filtering the contents of the main storage tank through a recirculating filter system. This can be made automatic and will reduce the potential for problems by removing sediment and gums. The filters should be checked and changed at regular intervals. When the filter change interval reaches a certain frequency then the fuel should be changed over.
• Tanks should be emptied and cleaned at least once every 10 years, or more frequently if there is a major contamination.
• Ensure that the fuel supplied conforms to a recognised specification, in Australia that would be AS3570, and ensure the fuel matches the winter cloud point for the area to avoid filter blocking by wax drop out in cold weather. .
• Always purchase fuel to replenish stocks in the winter season April - August. This will ensure that the fuel will not cause wax problems whatever season it is used.
• Obtain assurances from the supplier that all components are fully refined to promote stability.
• Establish a monitoring program whereby samples are taken at regular intervals to monitor the condition of the fuel. The samples can be examined at the site visually for evidence of haziness, sediment, darkening or sent to a laboratory for testing.
• Regularly turn the fuel over. If possible, plan the fuel usage so that it will all be used within 1-5 years and replaced with fresh fuel.
ADDITIVES TO IMPROVE STORAGE LIFE
The following additives can improve fuel storage life:
Issued : February 7, 2002 ADF1402
Supersedes : February 14, 2000 Page 3 of 3
BP Australia Limited
A.C.N. 004 085 616
Marketing Technical Services
• Metal deactivators. These work by stopping copper, zinc and other reactive metals from reacting with the fuel.
• Fungicides/Biocides. These work by stopping fungus and bacteria from growing in the fuel and so prolong the life of the fuel. They are only effective on fungus and bacteria and will not stop other oxidation reactions from taking place. They are normally active at the water fuel interface where the fungus and bacteria grow. If fungus is present then a kill dose is required. Otherwise a maintenance dose is used to stop fungus growing. The disadvantages of biocides are:
• handling and mixing is hazardous because they are poisons.
• for a kill dose, killing the fungus can lead to a build up of dead matter which will block filters and also cause the fuel to oxidise.
• ideally, the fungus should be killed and then the tank emptied and drained out.
• maintenance doses are effective but no more so than regular water draining.
• disposal of water bottoms requires special handling with due regard to the environment.
• Anti-Oxidants. These work by stopping the oxidation processes from taking place. They prevent the fuel oxidising and reduce the formation of sediment and gum.
• Fuel Stability Foam. FuelKleenik is a stability foam which is suspended in the diesel fuel in the tank. It has been developed and tested by Department of Defence and is claimed to keep the fuel stable for up to 10 years. The disadvantages are:
• it does not work where fungus and water are present which is why it is suspended in the fuel.
• its size is 2100mm x 200mm x 200mm so it has to be dropped in through a hatch.
After 15 years it has to be disposed of to landfill.
FuelKleenik is available from a company called FuelTreat ph 1800 034442 .
For further information, please call the
BP Lubricants and Fuels Technical Helpline
1800 033 558
freecall
or visit www.bp.com.au/fuelnews
I tend to believe that conditioners are best added when you first take on fuel, not after some time it has been sitting in the tank. In my case, since I only use my diesel for less than 50 hrs per season, I add a minimal bit of multi-conditioner "Pri-D" whenever I add fuel. And, with a lot of ULSD diesel fuel being sold in my area having only a cetane rating of 40, I also add a bit of cetane booster to bring the rating up to the required 45 as called for in my Yanmar manual. This improves starting and reduces smoke.
How about this case?
My baby has been on the hard for two years now, and hopefully (finances permitting), she'll be going back in this Spring. When I put her up a few years ago, I used stabilizer and algacide, but how long does it last? I have a bad feeling I'm looking at draining, cleaning, and refilling the tank.
What's the opinion guys (and gals)?
My baby has been on the hard for two years now, and hopefully (finances permitting), she'll be going back in this Spring. When I put her up a few years ago, I used stabilizer and algacide, but how long does it last? I have a bad feeling I'm looking at draining, cleaning, and refilling the tank.
What's the opinion guys (and gals)?
Re: How about this case?
Do it. You probably won't find out if there is a problem with the fuel until you get into some rough water and really, really, need that engine to keep running. Call a fuel polishing service. They will pump the fuel out, filter it, and spray it back in with enough pressure to wash off the tank walls. You will end up keeping and using most of the fuel.
Not having that nagging worry about what might be in the bottom of the tank ready to be sloshed up into the intake will be worth every penny even if the tank turns out to be fairly clean.
If you are one of those sailors who fills the tank about once a season, think about putting in a system like this:
http://www.rogerlongboats.com/FOpolishing.htm
an easy project to do before spring.
Do it. You probably won't find out if there is a problem with the fuel until you get into some rough water and really, really, need that engine to keep running. Call a fuel polishing service. They will pump the fuel out, filter it, and spray it back in with enough pressure to wash off the tank walls. You will end up keeping and using most of the fuel.
Not having that nagging worry about what might be in the bottom of the tank ready to be sloshed up into the intake will be worth every penny even if the tank turns out to be fairly clean.
If you are one of those sailors who fills the tank about once a season, think about putting in a system like this:
http://www.rogerlongboats.com/FOpolishing.htm
an easy project to do before spring.
If the tank was relatively full and had no water in it to start with, and you use both an biocide (technically it is a bacterium, not an algae) and stabilizer, I don't see why you'd have a problem. However, if your tank was grungy to begin with or had water sitting in the bottom or was mostly empty... yeah, you'll probably be doing the drain, clean and fill.
Re: How about this case?
Roger is right. If your tank has never been cleaned- if there is no opening it probably has not been cleaned- cut one and clean it out thoroughly. It is not so much what is in the fuel now- it is what has died and is sitting on the bottom just waiting fore some rough weather. I cut a hole and cleaned mine 3 years ago- it had never been done (1983 H34). I took about 2 gallons of crud that looked exactly like what you would take out of your eavetrough!!. If I had known that was in there I would have never ventured of the dock.
Roger is right. If your tank has never been cleaned- if there is no opening it probably has not been cleaned- cut one and clean it out thoroughly. It is not so much what is in the fuel now- it is what has died and is sitting on the bottom just waiting fore some rough weather. I cut a hole and cleaned mine 3 years ago- it had never been done (1983 H34). I took about 2 gallons of crud that looked exactly like what you would take out of your eavetrough!!. If I had known that was in there I would have never ventured of the dock.
Sailingdog has givin some good advice...I've had fuel sitting in tanks for several years and as long as it's been treated, burns fine.
My boat arrived by truck in Maine with the entire fuel system turned to jelly after the boat sat for an annual haulout that stretched into 6 years by accident. The tank was successfully cleaned and polished through the small hole for the Tempro tank gauge in one corner.
An inspection plate is nice but don't let the need to cut one stop you until you've talked to a polishing service. Above all, don't go at the tank with a drill and saber saw! Even diesel will sometimes explode under that kind of assult.
Later: I just read the instructions for this inspection port system
http://www.seabuilt.com/index.php
and they say it's OK to cut into a diesel tank with power tools. In the commercial world I come from, tanks are always cleaned and gas freed before being worked on so I won't recommend it but I pass on their opinion.
Last edited:
WOW, some interesting thoughts, but now I'm still a little confused. I neglected to mention that the tank was only one year old when the boat was laid up. Also, I AM one of those who only uses a tank per season. Does anyone know who polishes fuel int eh New London-Mystic CT area? Also, what does it cost? I take it a good old Racor wouldn't do the trick? I do have one in the set up.
Thanks to all!
Thanks to all!
Interesting reading from BP. There has been a lot of controversy on this subject. It was nice to see them validate keeping a tank full to reduce head space / condensation, but their concerns are probably more valid for multi-thousand gallon storage tanks. I do think that the idea of a drain at the bottom of a fuel tank is under rated. The aluminum tank in my boat is pinholing extensively at the front bottom welds due to water collecting there. I will replace with plastic, but will also consider placing a valve at a low spot.
I typically add conditioner to a fresh tank and spike it with the recommended maintenance dose every 60 days or so. I added stabil for the winter.
I typically add conditioner to a fresh tank and spike it with the recommended maintenance dose every 60 days or so. I added stabil for the winter.
The fuel only goes through your Racor once on it's way to the engine. To filter a lot of crud out of a tank, everything that goes through the filter has to pass through the engine. At current prices, it's an expensive (and slow) way to clean fuel. You may also need as much as a dozen 20 buck Racor filters to clean up a tank.
The published numbers for filtration are also statistical. It may say 10 micron on the filter element but it will be passing some larger particles that damage your injectors. As the filter gets loaded up with crud and pressure on it increases, more large particles will be extruded through it. When you recirculate fuel through a filter as in a polishing system, you eventually trap particles smaller than the filter's rating.
On board polishing system are not common because they are mostly prepackaged, expensive, setups aimed at larger engines. Sailboat auxilliary size systems can be so inexpensive and easy to install that there is no reason not to have one. They won't clean a fouled tank but, once the tank is clean, they will greatly extend the time between cleanings. They also clean the fuel well enough that you can use a finer element in your Racor since it will seldom, if ever, have any crud collect on it. It just becomes the final line of defence and back up.
Read about my system here:
http://www.rogerlongboats.com/FOpolishing.htm
http://www.rogerlongboats.com/StriderFuelSystem.htm
Someone I'm having a similar conversation with via email sent me this link:
http://www.seabuilt.com/index.php
Looks like a good product.
"An inspection plate is nice but don't let the need to cut one stop you until you've talked to a polishing service. Above all, don't go at the tank with a drill and saber saw! Even diesel will sometimes explode under that kind of assult."
I still would cut the hole and get my arm in there to clean out. I had to scrub the sides with clean kerosene and wipe every surface with clean paper towel. The muck in the bottom was so thick I cant see a polishing system handling it with out a lot of clogging at the pick up
I covered the hole with a piece of 3/16 or so Lexan screwed down every 1.5" and sealed with Permatex. You can find detail back in the archives
My tank is Poly - an easy cut with a utility knife I think my cost was less than 20$ ( cdn) for everything including the new garbage can to siphon the fuel into- I was on the hard.
I still would cut the hole and get my arm in there to clean out. I had to scrub the sides with clean kerosene and wipe every surface with clean paper towel. The muck in the bottom was so thick I cant see a polishing system handling it with out a lot of clogging at the pick up
I covered the hole with a piece of 3/16 or so Lexan screwed down every 1.5" and sealed with Permatex. You can find detail back in the archives
My tank is Poly - an easy cut with a utility knife I think my cost was less than 20$ ( cdn) for everything including the new garbage can to siphon the fuel into- I was on the hard.
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