The "old-timers" always talk about how things just aren't the way they used to be.
Those of us who work with stored diesel fuel realize that this is absolutely true when it comes to the storage life of diesel and other fuels. Diesel storage shelf life just isn't what it used to be There are a few simple explanations for this.
How bad is the problem?
If you look at technical manuals or fuel specifications rules written 15-20 years ago, they all talk about fuel storage life being 1.5 - 2 years. This was before market changes and ultra-low sulfur diesel came along. Now, they're finding changes in fuel composition after as little as 28 days. Now this is ok if the fuel is burned in an average span of time - surveys show that the average amount of time it takes to consume diesel fuel is 14-24 days after it leaves the refinery. But when the storage time exceeds this (such as for fuels for emergency backup systems), now there's real doubt that the fuel is going to perform as needed when needed.
Market forces are one cause
By market forces, we mean the skyrocketing demand for refined petroleum fuels around the world. 15-20 years ago, demand was less than it is now. On a worldwide scale, you have China and India consuming multiple times the amount of oil they did back then. So refineries have to scrape the bottom of the barrel (no pun intended) when it comes to squeezing every last drop of valuable refined fuel from each barrel of crude. Compared to the early 1980s, refineries are refining 85% more of each barrel of crude oil than they were back then. The resulting product has more unstable components created by the cracking processes the refineries are forced to use. And this means the storage life of these diesel fuel is much much lower than it used to be.
Ultra-low sulfur diesel is another
Ultra-low sulfur diesel fuels have dramatically lower storage life because they are more prone to being taken over by microbial problems. Removing the sulfur from the fuel results in a fuel with less natural ability to resist bacteria and fungus growing in it. And microbes like these will destroy stored fuel quality faster than anything. Hence it is important for stored fuel users to test their storage tanks for water and to use regular applications of biocides to prevent costly problems down the road.
Fixing low storage life for diesel fuels
Fuel stabilizers, water controllers and biocides are the trinity of treatments that can provide real value to stored fuels and their storage life over time. Fuel stabilizers interrupt the chemical reactions taking place in stored fuel after their exposure to oxygen and light. Water controllers work to absorb accumulated water so it won't create an easy environment for microbes to establish a foothold in the storage tank (microbes can't survive without accumulated water). Biocides are the only thing that will actually kill microbes in fuel, and therefore are important to use on a maintenance basis to prevent more costly problems down the road.
Check out these related posts:
- Guidelines For Long Term Fuel Storage Of Diesel And Storage Tanks
- Diesel Fuel Problems: The Doctor Is In
- How to Prevent Diesel Fuel Contamination
This post was published on December 19, 2013 and was updated on October 21, 2020.