ULSD Fuel tank rusting

[redbird2]

I just returned from a Fleet conference and training meeting, during a International presentation we got on the subject of ULSD 15 part per million, and Bio Diesel. For the last several years we have been having a hi number of fuel tanks replaced due to rusting inside the tanks. First it was the tank where made of all metal(steel) so they changed the liner coating to an Alumized coating to stop the rusting problem went away.

Now the problem is back after the switch to ULSD these tanks are starting to rust, they are seeing corrosion in the aluminum tanks as well, so they International has recommends cleaning the inside of all fuel tanks every year to remove the rust and gunk build up this is something they have just came to this in the last few months. they are requiring there dealers to purchase a special tool that will clean the inside of the tank and clean the fuel and put in back in the tank. I only had the a chance to speak with a Volvo engineer after the International presentation he confirmed this is a industry wide issue.

I know International has recommended that at least to are fleet that we should install a filter before the fuel pumps(transfer) to keep this rust and gunk out of the pumps.

We where told that BIO and ULSD inheriting attract moister, the sulfur acted as a natural algaecide. so now that we only have 15 ppm sulfur in fuel and we get water condensation then that in turn allow the algae to grow, one of the other speaker was a chemical engineer from the company that supplies fuel additives to the fuel manufactures he was telling in his talk that if you are seeing the black slimy filters these are coming from algae and bacteria growth in the fuel. Of course he add his little sales pitch at the end to buy a certain product they make that is to combat the problem.

I spoke with one of mangers about fuel he told me that his location has underground on site fuel storage. They test regular for water in there tank tanks been in the ground 5 years test regularly for leaking pass pressure test ever time so no leaks. 10 months after starting to have just ULSD in the tank water showed up, they also started to notice fuel in there davco fuel filters ( these have clear dome top with element inside ) a gunk in the filters when they would replace them so they decided to have a tank cleaning company come out and check and clean out the tank. So the tank was retested again no leaks held pressure, so they used a long optical camera lowered into the tank a found algae build up in the lowest point in the tank the sucked 300 gallons of this muck (looks like you sucked it out of the muddy creek) from the tanks. And now has to be treated a contaminate waste (big bucks)

So may be they are on to something with this I was just wanting to pass this along figure some of you might be interested.

please feel free to move this to a different forum

Greg

[Hubert]

I believe fuel additives as a minimum should be used periodically for tank and system maintenance.

I agreed with the post except the black slimy color on filters indicating algae problem. I have read filters turn black from the Asphalt or asphaltines ??? derivatives in the fuel and also if you collect enough crud, junk, dirt, and "stuff" its going to appear dark and or black.
As far a slimy not sure yeah that may be an issue but wet and dark may be considered slimy to some and its hard to quantify slimy.