Fuel Degradation In Storage
This entry was posted on February 16, 1999.
This article was written and submitted by Ralph E. Lewis from Power Research Inc.
Fuel Degradation in Storage - Are You Prepared?
Today as I write, I am sitting just two blocks from the Atlantic Ocean in our Fort Lauderdale, Florida office, atop a 10-story high rise on the Gulf-Intracoastal Waterway. This has me thinking. The tenants of our beach-front high rises, vulnerable to devastating storm surge, have no idea that the emergency services they'll depend upon may not be available—all because of a simple oversight. That neglected item is fuel. The service technicians that work on back-up generator systems tell us that about 70 percent of engine failures are fuel-related. I'm not surprised. Given a little heat, moisture and time, the oxidative process takes over quickly on today's stored fuels, creating gum, resin and varnish—cholesterol for a major engine coronary and power shut down.
A surprising number of engineers responsible for maintaining back-up power supplies for telephone companies, public utilities, hospitals, high rise apartments and condominiums are unaware that fresh fuel can go bad in just a matter of weeks. But you don't have to be left in the dark.
Have your own power generation source for one. Then make absolutely sure your fuel supply is in good condition. To ensure that fuel quality will be good for years requires only a few basic steps.
The problem begins with today's modern fuels. These so-called "clean" fuels typically deteriorate at much faster rates than fuels made 20 years ago. While all fuels suffer from the problem, most at risk are the EPA mandated reformulated gasolines (RFG) that contain oxygenate additives, derivatives of methyl alcohol and ethyl alcohol. We've seen gasoline have shelf life as little as a month—particularly if it is subjected to heat and moisture.
Diesel fuels fare a little better, but not much. Most all diesel fuel, including the EPA's mandated low sulfur version, has shelf life of from 3-to-6 months. Again, this varies widely. Recently we tracked a diesel fuel produced at a refinery in Texas to its final destination in Florida. When tested at the refinery the same day it was produced, the fuel barely met the specification for stability. After being stored, pumped into a coastal tanker, offloaded at Port Everglades, stored again, delivered to the fuel jobber, and finally to the customer, 23 days had passed. Again the fuel was tested. This "fresh" fuel now tested out of "spec."
In part, this has to do with new processing techniques developed by refiners in recent years. While the new refining methods are more efficient, producing more gasoline per barrel of crude, these fuels are often far less stable than the conventional "straight run" fuels we had before.
To make matters worse, the quality of the crude oil feedstock going into the refinery changes daily with each shipment. Processing equipment must be precisely adjusted to these varying qualities, but it doesn't always happen. This neglect results in poorly processed, less stable fuels. One oil company survey indicates that at least 50 percent of the gasoline sold today is substandard.
Oxygenated fuels are also less fuel efficient, giving a minimum drop in fuel economy of 3 percent (if you believe the major oil companies—much higher if you listen to those among us who are fuel misers and check mpg regularly.) Additionally, there is strong evidence that these fuels pose dire health and environmental consequences. Public interest groups have assembled a large amount of data on the damaging effects of oxygenated fuels.
So how should you store and protect fuel?
First, avoid underground storage. The EPA requirements for underground storage has made this prohibitively expensive for Joe Citizen. The requirements are strict. If you get caught storing fuel underground, the penalties are tough, the fines high. But there are alternatives. On a small scale, there are always 5-gallon military surplus "Jerry-cans." They are inexpensive and durable. But you'll need a lot of them if your fuel supply needs are great.
Consider portable nylon fuel tanks on wheels; typically of 23-gallon size and available at marine supply stores like Boater's World and West Marine. Next option is auxiliary tanks for vehicles and pickups. Many truck supply companies manufacture tanks that fit in pickup beds. The Internet is a good source to search for "auxiliary truck fuel tanks" (or derivitives of that search term).
Don't use "Poly" drums for fuel storage! Consider using 55-gallon steel drums. These must be stored in a well ventilated area away from heat. "Poly" drums—the type sold for water storage—are made of high density plastic, and should not be used to store fuel. Over time, the fuel will react with the plastic (a hydrocarbon) and gradually deteriorate the drum interior.
Large surface storage tanks with capacities of 250 gallons plus are the best alternative. Many commercial fuel suppliers or "jobbers" that dispense gas, diesel and home heating oil, lease or sell these tanks. They can at least direct you to a good source. You may also wish to contact industrial tank manufacturers. Check the classifieds for auctions of industrial equipment. This is a great way to pick up tanks at bargain basement prices.
If you live in an urban area, small 5-gallon nylon or metal storage cans will have to do. If you have access to, or own rural property, then above ground tankage is the answer. Place your tank in a cool, shaded area if outdoors. Best yet, put your tank in an indoor, covered location. Remember that heat from sunlight will speed the oxidative process in stored fuel; and temperature swings will cause condensation to build, resulting in water accumulation in tank bottoms. Whatever tank you use, make sure it is equipped with a valve on the tank bottom so that you can periodically drain any water accumulation.
Keep your tank topped off, leaving about 5-10 percent of capacity free for headspace. The same holds true for steel drums. This minimizes condensation, yet gives room for fuel to expand and contract with temperature variances. Invest in a good quality spin-on fuel filter that separates water. Put this on the output line from the tank, whether you are using gasoline or diesel fuel. They make small ones for small tanks, and they are commonly available at marine supply stores.
Keep a good supply of spare fuel filter cartridges on hand. Additionally, avoid the use of copper or any copper brazing on your tank. Minute particles of copper can contaminate the fuel, and these few particles can actually accelerate fuel deterioration.
Even with optimum physical storage conditions, fuel will still degrade in time without proper fuel treatment.
Industrial Grade Fuel Stabilizers
That's where we come in. My company, Power Research Inc., manufacturers industrial-grade fuel stability chemistries for long term fuel storage for diesel and gasoline. The original formulas were developed for refineries more than 40 years ago for bulk fuel storage, and today, our ongoing research program has developed optimum formulas that can extend the life of today's modern fuels for many years at a time.
How long can PRI keep fuel fresh? This depends on the original condition of the fuel. While tests indicate that PRI can keep fuels fresh in many instances for 10 years and more, fuel should be dosed with PRI every 6-12 months for maximum benefit. If your fuel is already in poor condition, not to worry. PRI-D for diesel, and PRI-G for gasoline have also demonstrated an uncanny capability to restore very old, stale fuels to a refinery fresh conditions.
In one extreme case, a doubting client took a 15-year old sample of some very gummy and malodorous gasoline from a junkyard car in New Hampshire. He sent the sample to Saybolt Laboratories in Boston for analysis. Predictably, the fuel was completely unusable when tested for oxidation stability. When treated and re-tested with PRI-G, this bad fuel was completely restored to refinery freshness.
We recently had another similar case with a Caribbean-based client. The engines for his back-up power generation unit simply would not run on the stored fuel. We had the fuel tested for accelerated stability at an independent laboratory at Port Everglades, Florida. This fuel was out of specification by more than fifteen-fold, the worst I have ever seen in my 25-years of fuel experience. Again, PRI-D did the job. After treatment, this very challenging diesel fuel was brought into specifications. Our client's engines ran as if nothing had happened.
The key to PRI chemistry is our proprietary enhanced thermal stability chemistry. This unique chemistry is not available in the "consumer" additives at auto parts stores and marine and RV supply outfits. We've had many of these products independently tested, and not surprisingly, the majority of these "stabilizers" do little or nothing to preserve fuels. Some even make the fuel worse. The fact that some manufacturers heavily dilute these formulas with common solvent carriers—reducing their strength—is evidenced by the poor treatment rates of these products. This also makes them very expensive on a per treated gallon basis.
We've kept our same industrial formula and treat rate in our consumer packages of PRI-D and PRI-G. One quart of PRI will treat 512 gallons of fuel, and at a most economical cost. You are assured of getting the most effective, industrial-grade chemistry available in the world today.
Additionally, PRI contains no toxic biocides, or fuel-drying alcohol or glycol. But it will eliminate the conditions that lead to algae growth in diesel fuel tanks. If you already have slime from algae, PRI safely dissolves it and other sludge or gums in your tank, allowing it all to be eliminated during combustion. PRI also prevents tank corrosion. Your days of expensive "fuel polishing" and tank cleaning are over!
Many people are unaware that about 85 percent of our business is treating the heavy "bunker" fuel oil consumed by the world's great merchant and cruise shipping companies. This fuel is of a far worse quality than diesel and gasoline, yet PRI's thermal stability chemistry prevents hard carbon deposits from forming on critical engine components, saving these companies hundreds of thousands of dollars annually per year by dramatically reducing engine wear rates and improving fuel economy.
Independently conducted emissions tests on ships, industrial facilities and power plants confirm that PRI treatment also results in smoke reductions of up to 50 percent, and dramatic reductions in ozone producing oxides of nitrogen emissions (NOx) and sulfur dioxide emissions (SO2).
We do the same for your cars, trucks, RVs and back-up generators, using the same chemistry that treats fuel for the world's largest engines. PRI's average fuel economy improvement for onshore vehicles is 8.8 percent. PRI also restores power and economy to engines running on oxygenated fuels.
PRI has a long history on two-stroke engines, the kind that power gasoline generators. Because of their design, the typical carbureted two-stroke engine has a tendency to produce far more carbon to foul internal components when the fuel is left untreated. Since PRI prevents carbon formation during combustion, it is ideal for two-strokes when added to the fuel/oil mixture. Additionally, PRI-G also stabilizes the oil when it is mixed with the gasoline in these engines. As a result, PRI-G will keep your generator free of damaging hard carbon deposits, ensuring a much longer engine life and many more hours of reliable service.
Last, remember the point about copper degrading fuel? Not to worry. All PRI chemistries have "metal de-activators" that eliminate the problem if it is impossible to make any changes. Second, PRI contains a series of corrosion inhibitors that will keep rust from forming in metal tanks. PRI will even dissolve existing corrosion in case you forgot to look inside before you filled your tank with fuel.
In automobiles, your engines will outlast the metal bodywork surrounding them. Time between engine overhauls can be doubled and more, verified by long term usage of PRI on commercial fleet systems. Have you ever seen those pictures of Fidel's Havana with the old 1950s cars still chugging along? Sometimes I wonder if someone is smuggling PRI into Cuba.
-- Ralph Lewis