Thanks Talbot, I am glad you waded in there and please send my regards to your friend for his help. I too was shocked at the mis-information given. But there tends to be an aweful lot of it in the fule industry and MOST ALL of it tends to come from Additive manufacturers.
From a chemistry point of view,
Diesel does not have any "free" atoms that want to attrach water molicules to the chains. Ethanol does and any Ethanol added to Diesel will absorb water. As Nigel Luther has stated, much of the transportation of Fuels around the world uses water and even the storage tank beneath your bowser is sometimes "balasted" with water. We have some places here in NZ that if the underground tanks are not filled with water as the fuel is removed, the tank will float out of the ground due to the high water table. Many bulk storage facilities use water to "float" the fuel. It replaces the fuel so as the tank does not collapse, it reduces the airspace in the tank and it can mean fuel is run by gravity and not pumped. Our Fule transport ship uses this same technegue to remove it's fuel from the ships hold to the
dock storage facilities.
Don't be fooled Darryl, Condenstaion on the inside of a warm fuel tank is the No1 enemy to producing water in your tank. And any fuel system that uses "return to tank" systems are suseptable to this issue. It promote that you return to fuel line and not tank. Although that can not be done with the very modern high pressure high flow rate engines.
By the way, a dissicant will not remove enough moisture from the air to warrant it's use. It would need to be heated and dried daily or even more to remove the water itself absorbs.
Fuel does not degrade "into" something else and acumulate on tank walls needing to be cleaned every 5-6yrs. That is purely contamination external to the fuel itself. "Old" fuels are subject to the Aromatics and solvents evaporating and causing the fuel to become "unbalanced". That is a major factor in Petrol(Gasoline). But in Diesel, the "raw fuel" is still
oil and most Diesels will burn raw
oil. Just maybe not efficinetly nor cleanly.
What does accur in todays "modern" fuels, is what the additives do. Once again Additives like Methanol are the biggest issues. But we now have another problem in todays "modern" fuel. The reduction and
removal of Sulfur. The "process" reduction of Sulfur also removes many of the Aromatics in Diesel. This is causing some big problems and in some(only a small few) instances, Oil companies are re-balancing Aromatics to re-establish the correct make up of the fuel. But in many instances this is not happening and we get a very "dry"(not water but chemical) fuel that causes issues with O-rings and
seals.
The biggest
single issue with fuel storage is Bacteria and algae. They will ONLY grow in the presence of water. Remove the water and you have no Growth. Dose the fuel tank periodicaly and you also reduce the chance of growth in the tank. and finaly, A GOOD FILTER/WATER TRAP is a MUST.
P.S Talbot, I stand to be corrected by your friend Mr Luther if I have anything wrong above. I would enjoy the "honing" of my knowledge.