Fuel polishing--dirty diesel fuel tanks

[BandB]

Not wanting to cause an argument, but I disagree.


Proper filters remove water. That's not difficult to achieve yourself, you really don't need to engage the expensive services of a professional who makes it sound complicated.

And I disagree and there is far more to polishing than just removing water. Removing water is easy. Removing sludge not that hard. Restoring quality to the fuel more difficult, leaving the tanks clean and the fuel clean and with all the characteristics of new far more difficult.

You're right, if all one is doing is removing water, then the charges for polishing are very high, but in most cases when professionals are called, more than water removal is needed.

You are also correct in pointing out the value of coalescers in addition to centrifuges.

Polishing is the careful removal of non-combustible contaminates below levels stated in ASTM D975 (Standard Specification for Diesel Fuel Oils) while re-suspending (keeping) combustible contaminates to maintain ASTM standards for BTU value, lubricity, and cetane. The main difference between polishing and filtering is that fuel polishing acknowledges that fuel itself can degrade/consolidate (clump together into solids) and that it needs to be kept, where as fuel filtering does not. Fuel polishing recognizes that combustible contaminates should be changed back to their original form and re-suspended in the fuel so the fuel stays within industry specifications and functions as it’s intended to. Fuel filtering ignores that and simply pulls all contaminates out without regard for their value to the fuel and the engine.

Now the other task typically being paid for that pushes the price up in the cleaning of the tank. You have fuel problems, clean the fuel, put it back in a dirty tank and you haven't completed the task. True professionals are going to clean your tank or tanks.

If someone just got a little water in their last fuel purchase, then complete polishing isn't required. It can all be filtered. However, if someone has a recurring problem, and most often if they're dealing with fuel and a tank that have set for years unused or someone has issues with other contaminants then more is often required. Professional polishing and tank cleaning is expensive but justifies itself if really needed. If that's not needed then there are cheaper solutions.

We have an Alfa Laval system on the boat we're on at the moment, because we do cruise often outside the US and fuel in many different areas plus we make longer ocean runs. We don't have a polishing system, just a good filtration system, on boats that never leave the US and never venture far offshore.

 

[Knot Salted]

Looks like 'bugs'. Biological activity in diesel is only possible when free moisture is present. The critters live in the water, and eat the fuel. It is never algae unless you have light in your tanks. 300 varieties of yeasts, molds, fungi, and bacteria are the culprits. Get tanks clean, then always use a good non-alcohol additive that has glycol ether (jet fuel de-icer) in it. Add just before fueling at recomended dosage for severe conditions. This is safe for all fuel and injection systems of all ages. The de-icer dissolves the water into the fuel where the bugs cannot use it, and it safely passes through to the combustion chamber and out the exhaust. Most will also contain metal deactivators, corrosion inhibitors, lubricity agents, stabilizers and detergents for the injectors. This will make a real difference in reliability, durability, and even in fuel consumption rates.

 

[FF]

"The de-icer dissolves the water into the fuel where the bugs cannot use it, and it safely passes through to the combustion chamber and out the exhaust."

Emulsifying tiny water might work, but with more serious water the temperature in the injector tip can cause the water to boil. And become steam.

Blown off injector tips does happen.

 

[nodestination]

I paid $400 for tank cleaning and fuel polishing. I got 250g tank. For $4000, you can buy your own polishing machine.

 

[Steve DAntonio]

Steve

When will your shore power transformer article be available?

This article is now available in the Ocean Voyager digital edition, available here...

http://www.navigatorpublishing.com/ondigital/ON240_OV17_digital_editon.pdf

 

[Knot Salted]

Right, but not with the jet fuel de icing component.
We and the industry have been doing this in commercial on and off road and passeger diesels for decades.

 

[Trundlebug]

Removal of the moisture at source is intrinsically better, I would suggest, than treating the moisture with a special additive.

As I said, if there's no water, the bugs can't be there.

 

[Knot Salted]

Removal of the moisture at source is intrinsically better, I would suggest, than treating the moisture with a special additive.

As I said, if there's no water, the bugs can't be there.

Yes. Then the additives help prevent future accumulation via entrained or introduced moisture.

 

[FF]

"I would suggest, than treating the moisture with a special additive."

If only it were that simple.

An emulsifier will grab the water and carry it to the engine where perhaps the filter can stop the water.

If it doesen't it gets really expensive.

A de emulsifier will drop the water out of suspension to the tank bottom, where you have to figure out how to remove it.

Only the de emulsifier can handle big water in the fuel .

With no chemicals and only time a sump can remove big water or little water at no expense, besides effort and time.

 

[User915]

Removal of the moisture at source is intrinsically better, I would suggest, than treating the moisture with a special additive.

As I said, if there's no water, the bugs can't be there.

Trundlebug, it's always good to provide full information at the point.
This is not a matter of water only, it's an issue with oxygen of water AND air as already stated in post #39.

Bacteria found in our fuel and water tanks need source of energy to develop and grow. Those bacteria, called 'aerobic bacteria', mostly & usually get energy from oxygen of air & water.

However bacteria do need time to multiply to achieve a sufficiently large population by their dividing process then through a chain reaction to have a strong corrosive effect on the surface of the tanks walls.

Therefore by keeping our tanks full of fuel which reduce the volume of air, also by frequently draining off the remaining condensation water & water in fuel, this is depriving them of essential resources then bacteria are no longer being to develop.

 

[Steve DAntonio]

"The de-icer dissolves the water into the fuel where the bugs cannot use it, and it safely passes through to the combustion chamber and out the exhaust."

Emulsifying tiny water might work, but with more serious water the temperature in the injector tip can cause the water to boil. And become steam.

Blown off injector tips does happen.

With respect for FF's knowledge and practical experience, while the is no doubt that water can wreak havoc with fuel injection systems, and water emulsifier additives carry with them liabilities, primarily why would one would encourage water to mix with fuel when we expend a great deal of effort to install and maintain water separation fuel filters, the 'water boils and turns to steam in an injector and blows the tip off' is a long-held, and often repeated misconception. At the pressure found inside an injector, it is impossible for steam to exist. Water is just plain bad in fuel, emulsified or not. It's best to make every effort to drain it from tank bottoms and catch it in filters, rather than inducing it to pass through the fuel injection system.

 

[rwidman]

It would be great if boat fuel tanks had a sump at the lowest point and a means to drain any water out of them, but in reality, most do not. Mine don't, they are rectangular tanks with flat bottoms.


This leaves me with filters, chemicals and trying to keep water out in the first place.


The fuel fill plates are directly under the flybridge drains. U till a few weeks ago, I couldn't take on fuel in the rain. I finally got the bright idea of buying rubber stoppers for the drain hoses. I'm a little better off now.

 

[Yahoo 1]

It would be great if boat fuel tanks had a sump at the lowest point and a means to drain any water out of them.

Yes ! +1

 

[The Other Gary]

And maintaining the O rings on filler caps is a priority as well or the next deck wash may end up in the tank with many fuel fill setups.

 

[FF]

"It would be great if boat fuel tanks had a sump at the lowest point and a means to drain any water out of them." Yes but that would asd price to the vessel.

Unless the first purchaser is knowledgable enough to demand a marine fuel tank, instead of a box for fuel,a box is what you get.

Some folks tanks get so bad they install an aftermarket port to clean the tank, doesn't seem it would be big bucks to install a low point drain at the same time. A plug in the drain valve might be a good safety.

Installing a low point suction pipe down thru the fill pipe might also be possible with the tank open to place the end properly.

 

[rwidman]

In my case and probably many others, the bottom of the tank is flat and rests on a flat surface. The only way to provide a sump and drain would be to raise the tank and reduce capacity.


As far as "demanding" anything, it's unlikely you will get it unless you're having a custom boat built.

 

[FF]

"As far as "demanding" anything, it's unlikely you will get it unless you're having a custom boat built."

Perhaps , back when most of the TT were built hulls would be popped and passed to different yards even used as wedding presents.

If the groom could complete and sell the boat , he was then in business.

The brokers would sell boats yet to be built, so semi custom was really simple , although it might be a year to get the boat.

I never purchased one of these boats but commissioned a bunch.

If the current Orential boat market is similar all that would be required is a good drawing of a real fuel tank with self servicing sump, so they could copy it.

The folks replacing a shot fuel box might easily have a fuel tank created.

One method could be a bladder in the old fuel box , , no sump , but if contaminated it could be removed and cleaned.

 

[Steve DAntonio]

It would be great if boat fuel tanks had a sump at the lowest point and a means to drain any water out of them, but in reality, most do not. Mine don't, they are rectangular tanks with flat bottoms.

This leaves me with filters, chemicals and trying to keep water out in the first place.

The fuel fill plates are directly under the flybridge drains. U till a few weeks ago, I couldn't take on fuel in the rain. I finally got the bright idea of buying rubber stoppers for the drain hoses. I'm a little better off now.

WesK: On nearly all new and after build fuel polishing systems I've installed, I've included what's referred to as a stripper tube. This is a tube that's permanently installed, which extends to the bottom of the tank, closer to the bottom than the pick up tube, and preferably to the lowest part of the tank (in a well if I'm designing the tank, if the tank is being designed, a drain can be incorporated into the well, in place of the pickup tube, if space permits) where water will accumulate. If not used with a polishing system, it can be a stand-alone device plumbed to either a hand pump, or an oil change pump. Operated regularly, and briefly, it will tell you very quickly if water is present, and running it until clear fuel emerges will remove that water.

The tube is typically installed in the existing inspection port (doing so enables the port to be removed and brought into the shop for installation of a welding boss, eliminating the need to weld on the tank, and aboard the boat), even if on the tank side , with a 90 deg. pick up, or a dedicated inspection port can be installed, tank top or side, as a platform for the tube. This isn't theory, I've done all of this on many occasions.

An explanation of these systems (along with photos of the 90 degree pick ups and systems) are shown in this article Fuel Polishing Systems Explained | Steve D'Antonio Marine Consulting

Additional system installation photos are shown in this article as well, similar text but written for the marine industry http://stevedmarineconsulting.com/wp-content/uploads/2014/03/FuelPolishing_PBB112_opt.pdf

And while we're at it, this article, again written for the industry, covers centrifugal filters http://stevedmarineconsulting.com/wp-content/uploads/2014/03/CentrifugeFilters115_05.pdf

 

[angus99]

Thanks, Steve, for solving something I've been wrestling with. Been wondering how to install a fitting that will pull water/fuel from the bottom of the tank and into the polishing system--but thought adding another fitting to the tanks would be expensive and still likely not drain whatever's on the bottom. The plate-mounted pickups look like a great solution.

(There are actually some older fittings near the bottom of our saddle tanks that are plugged with fiberglass. I'm assuming they were the original fuel outlets but were picking up too much crud that close to the bottom--and still not draining water that might have been on the very bottom. The photo is rotated 90 degrees clockwise.)

Thanks, too, for your excellent presentation on running gear at last week's Defever rendezvous.

 

[dhays]

And maintaining the O rings on filler caps is a priority as well or the next deck wash may end up in the tank with many fuel fill setups.

This is something that I am notoriously bad at doing. I need to see about replacing all my O rings on the boat simply because I doubt they have been changed since the boat was new.

I am fortunate that my fuel fills are in the aft cockpit out of the weather.

 

[FF]

"I am fortunate that my fuel fills are in the aft cockpit out of the weather."


To assure no fuel hassles we removed the deck fill unit and installed a pipe with std plumbing cap an inch lower..

The deck was cut open to receive a 6 inch bronze flush deck plate.

If the plate was missing water could not enter the std plumbing cap even a loose hand tight.

6 and 8 inch deck plates in plastic are as effective and far cheaper than bronze.

With a bit of effort relying on deck fitting 0 rings need not be done.

 

[O C Diver]

This is something that I am notoriously bad at doing. I need to see about replacing all my O rings on the boat simply because I doubt they have been changed since the boat was new.

This is one of those things that needs to be on the annual spring maintenance list. Every spring I buy 7 new orings for all the fills and replace the perfectly good ones that are there. Costs less than $5 and is some of the cheapest peace of mind you can buy.

Ted

 

[rwidman]

Steve D and FF, I appreciate the input, but I think most of us either buy a previously owned boat or a production boat. It's not hard to imagine the ideal fuel tank setup but we don't usually get to specify any such requirements, we take what we get and do the best we can.

In my case, there are no inspection ports so pretty much the only way to draw fuel/water from the absolute bottom of the tanks would be through the fuel fill (which is not straight but has an "S shaped hose) with a flexible hose with a weight on the bottom.

The bottom of the tank is flat so there's no guarantee of getting all the water out even by doing that.

I try to keep my tanks filled to minimize condensation and I try to buy fuel at reputable places. I use Stanadyne treatment. So far, it has worked.

 

[dhays]

This is one of those things that needs to be on the annual spring maintenance list. Every spring I buy 7 new orings for all the fills and replace the perfectly good ones that are there. Costs less than $5 and is some of the cheapest peace of mind you can buy.



Ted

Great point Ted. I am gong to get some O rings.

 

[dhays]

I try to keep my tanks filled to minimize condensation and I try to buy fuel at reputable places. I use Stanadyne treatment. So far, it has worked.

While we have all heard about the issues of condensation in partially full fuel tanks, I am not sure it is really as big an issue as we might think.

Somewhere I read an article where someone did some testing to see if an empty tank would develop water through condensation and could find evidence of it. I don't recall who did it. CMS maybe?

 

[Bacchus]

While we have all heard about the issues of condensation in partially full fuel tanks, I am not sure it is really as big an issue as we might think.

Somewhere I read an article where someone did some testing to see if an empty tank would develop water through condensation and could find evidence of it. I don't recall who did it. CMS maybe?

Dave
I recall reading a test done by RC at CMS that showed no accumulation of condensate in a tank over EXTENDED time - only issue cited was the tank was empty and the possibility of evaporation was noted as a possible explanation that wouldn't be the case w/ diesel above any condensate.
His test shows what happens w/ empty tanks - not sure it can be extrapolated to partially full tanks... but I haven't ran ANY tests so what do I know!

 

[BandB]

Dave
I recall reading a test done by RC at CMS that showed no accumulation of condensate in a tank over EXTENDED time - only issue cited was the tank was empty and the possibility of evaporation was noted as a possible explanation that wouldn't be the case w/ diesel above any condensate.
His test shows what happens w/ empty tanks - not sure it can be extrapolated to partially full tanks... but I haven't ran ANY tests so what do I know!

I think for many it's a carryover from gas, where it is an issue.

 

[Yahoo 1]

While we have all heard about the issues of condensation in partially full fuel tanks, I am not sure it is really as big an issue as we might think.

Somewhere I read an article where someone did some testing to see if an empty tank would develop water through condensation and could find evidence of it. I don't recall who did it. CMS maybe?

Water from the air in a empty or insufficiently fulfilled closed tank will condense in the inside walls of the tank as a direct consequence to changes of temperature at the outside of the tank, no matter what type of fuel or liquid contained in the tank.

Edit:
For those of which fuel tanks are in the Engine Room:
When the temperature drops outside of the tank (after engine shutdown), condensation particulary forms within the tank due to the removal of latent heat from the air in the tank.

Reduce the volume of air, you reduce the condensation process.

 

[psneeld]

In theory, but in actual practice, I have never seen enough condensation in any of hundreds of boat and empty fuel tanks to matter worth a spit.

I hold it up to the old wives tale/urban legend crap.

See post 86 for the reference to the test run at CMS.

Theoretical...but only in very unusual circumstances or in just the right environment do you collect enough condensation to matter.

Which does not include, NJ, Fl, Al, AK..... USA.....which spans a pretty good set of environmental situations.

Free water entry from fuel fills, vents, marina tanks are all a much bigger concern of mine.

 

[Yahoo 1]

I hold it up to the old wives tale/urban legend crap.

Why are you so snarky ? I am aware that I am only a newbie here, but as far as I know, I don't have to accept your unpleasant comment - not to say misogynous -.

Have you got the impression that your comment has moved things forward and if so how?