Now that we seem to have emerged from a protracted winter, summer’s hot temps are just around the corner. Check out this edition of Guttman Energy’s Tank Tips for some important tips to ensure your equipment operates smoothly when the dog days of summer hit.
Rusting in ULSD Tank Systems
The Problem
It has long been a question as to what exactly causes premature corrosion in ULSD tanks. Although theories ranged from improper grounding to fuel soaps, the more we learn the more it looks like microbial contamination, or “bugs,” may be the culprit.
The change from LSD to ULSD had more impact than just lowering emissions. It reduced the amount of naturally occurring biocides, such as sulfur and certain aromatics. ULSD also doesn’t hold as much water as higher sulfur fuels, making any water in the tank a problem. With these changes, the increase in bug growth in tanks has been inevitable.
There are two separate types of bugs that can live in your tank: aerobic (needing oxygen) and anaerobic (not needing oxygen). The anaerobes typically generate the acids that cause damage. The acids have a higher vapor pressure than diesel fuel, which makes them rise to the top of the system. This is why many tank owners are seeing rust above the fuel level, which was previously unheard of. Cleaning the system and removing rust can be quite costly and may interrupt your daily operation.
The Solution
Avoid having any water in your tank or tank system. If possible, drain water frequently and remove all water bottoms. Not only will this help with the bugs, and ultimately rust, it also will help with filter and fuel system clogging. Tanks can also be periodically treated with a preventative dose of biocide additives. Contact your sales representative if you think you have a problem.
The takeaway: no water, no bugs, no rust!
Best Practices
- Make sure that all rain runoff is diverted so that it doesn’t run over or near tank fills. Similarly, in winter do not pile snow over fills or where it will melt into the fill area.
- Ensure that fuel fill caps fit properly. This includes making sure that the seals are tight and caps are not broken.
- Check tank vents for signs of leakage or areas where water could enter the system.
- On a regular basis, stick your tanks using water-finding paste.
Clear the spill bucket of water and debris. Ensure there is no plug that encourages water to be drained from the spill bucket into the tank.
