Fuel Storage Tank Maintenance - Keep It Clean

Keep It Clean - Fuel Storage Tank Maintenance

Most owners and operators of fuel storage tanks do not understand that maintenance is required to safely and successfully operate fuel storage tanks.

We constantly hear that customers have tanks that have never been cleaned and worse yet, that they believe that they never need to check to see if they have any problems.

This is made even worse by the information that some fuel suppliers tell their customers; for example that it OK to have some water at the bottom of the tank.

Well here is some real world information for everyone on this subject.

Fuel Storage Tanks all require regular maintenance. They are designed with the pickup tube 3" to 6" from the tank bottom so that small amounts of water, sediment and other contaminants have a space they can settle out so that they will not be drawn into the vehicle or equipment tanks as fuel is pumped out. This water and sediment material will accumulate over time and will cause problems if not removed periodically.

Some will tell you that 1/2" or 1" or even 2" of water is alright, and they are flat out wrong. Every time fuel is transferred into that tank it stirs up all that material and it may take as long as a day for it to settle out again. In the meantime every tank you dispense fuel into gets some of this material.

If you have a steel tank that water is corroding your tank from the inside out and putting rust particles into your fuel. We often find above ground tanks only a few years old that have rusted from the inside to the point of leaking from water and sludge in the tank.

Many customers have electronic monitoring systems that provide constant readings showing fuel level, water level, and leak detection. Some of these customers will see 1/2" or a few gallons of water on these system and ignore it because they have been told it is not important.

One problem we see time and again is that the sensors on these monitoring systems fail and they don't tell you when they fail, they just go on showing the last reading forever. This goes on until they start pumping water into their equipment at which point someone checks the tank with a stick and water finding paste only find that they actually have several inches of water.

We have told all of our customers for many years that even though you have spent several thousand dollars for a state of the art monitoring system, you still need to have some one check every tank at least once a month with a stick and water finding paste.

And this rule should be written next to the monitor and maybe next to where you store the measuring stick: "The Only Acceptable Amount of Water in Any Fuel Storage Tank is ZERO (0)".

For those of your with in-ground steel tanks, these tanks have Sacrificial Anodes attached to them. These Anodes take the weak electrical current generated by the tank and pass it into the ground through them. This prevents the tank metal from corroding, however the Anode "Sacrifices" itself in this process. The Anode is used up over a period of time. When the Anode is "used up" the tank begins to corrode often very quickly. Tank owners should periodically check these Anodes and Replace them as necessary. In many states this is part of the required maintenance and testing procedures, however you should know this and check to be certain it has been properly done.

Caps, Sumps, and Vents should all be checked for integrity and to see that they are doing their intended job.

Fuel Storage is a vital link in getting clean fresh fuel safely and efficiently into vehicles and equipment. You have a big investment in the tank, its installation, and in the fuel in it. It only makes sense to properly maintain and protect this investment.

Today we have new challenges with Ultra-Low Sulfur Diesel (ULSD), Biodiesel, Gasohol, Conventional Gasoline, and Reformulated Gasoline containing any amount of Ethanol. These fuel products hold much higher levels of water and are much more corrosive than fuels we have traditionally dealt with. They require much higher levels of monitoring and maintenance to have a safe and trouble free delivery system.

We are happy to offer analysis and suggestions on how to operate and maintain your systems.

Please post your comments or questions here.

Diesel Doctor

Phase Separation in Ethanol Blended Gasoline

Phase Separation in Ethanol Blended Gasoline’s

Phase Separation in Gasoline’s containing Ethanol is now a major problem for all users of gasoline.

Whether you use gasoline as a fleet operator or for your family car, classic car, boat, personal water-craft, motorcycle, snowmobile, ATV, RV, lawnmower, weed-whacker, generator, or any of the thousands of other types of equipment that use gasoline engines; you are being affected by Ethanol in your fuel.

Phase Separation describes what happens to gasoline containing Ethanol when water is present. When gasoline containing even small amounts of Ethanol comes in contact with water, either liquid or in the form of humidity; the Ethanol will pick-up and absorb some or all of that water. When it reaches a saturation point the Ethanol and water will Phase Separate, actually coming out of solution and forming two or three distinct layers in the tank.

Phase Separation is also temperature dependent. For example, E-10 can hold approximately .05% water at 60°F. To better understand the amount of water that we are talking about, picture 1 gallon of E-10 at 60°F. This gallon will hold approximately 3.8 teaspoons of water. However if the temperature drops to 20°F it can only hold about 2.8 teaspoons of water.

We recently were called to consult for a fleet where a fairly large number of vehicles were being regularly fueled from a single tank and about one-half the vehicles were stored inside and the other half were stored outside. After a night with a 30°F+ temperature drop, several of the vehicles stored outside developed problems with significant amounts of water found in the vehicle tanks. After checking the storage tank and finding no measurable water, they looked for other possible causes including sabotage. After looking at many possible causes this customer consulted with us and we were able to describe the Phase Separation through temperature change scenario and determine that this was the most likely cause of the problems.

Phase Separation can happen in an underground or an aboveground storage tank, a vehicle tank, a boat tank, in any type of equipment tank, and even in the gas can in your garage.

When this happens, you can have serious and even catastrophic engine problems, without warning.

When this Phase Separation occurs you will have an upper layer of gasoline with a milky layer of Ethanol and Water below it, and then in many cases a third layer of just water at the bottom.

If this happens and you try to start the engine you can have one or more of the following problems. If your fuel tank pick-up tube is in the water layer, most likely the engine will fail to start. If the engine is running and suddenly draws water you can have damage from thermal shock or hydro-lock. If the pick-up tube draws the Ethanol-Water mixture or just Ethanol you can have problems where the engine will operate in an extreme lean condition, which can cause significant damage or even catastrophic failure. If the pick-up tube draws the gasoline, it will operate very poorly due to lower octane that is the result of no longer having the Ethanol in the fuel.

Gasoline containing Ethanol provides further challenges and dangers for marine operators (Boaters) and other users of seasonal equipment such as motorcycles, personal water-craft, snowmobiles, ATV’s, RV’s, yard maintenance, generators, and other equipment.

Ethanol is a strong, aggressive solvent and will cause problems with rubber hoses, o-rings, seals, and gaskets. These problems are worse during extended storage when significant deterioration will take place. Hoses will delaminate, o-rings will soften and break down, and fuel system components made from certain types of plastics will either soften or become hard and brittle, eventually failing. Fuel system components made from brass, copper, and aluminum will oxidize to the point of failure.

Operators of boats with fiberglass fuel tanks built before 1993 can have actual structural failure as Ethanol will break down and pick-up some of the materials the tanks are made from. This causes two separate but equally serious problems. First the tanks can become so weakened that they can fail. In cases where the tank is part of the boats structure we have seen tanks become so weak that it is possible to collapse part of the deck just by walking on it. The second problem is that this material when dissolved from the fiberglass tank is carried through the fuel system and can cause damage to carburetors and fuel injectors and can actually get into the combustion chambers causing damaging deposits on valves and pistons. This material can be nearly impossible to remove without destroying the affected parts.

Two-Cycle engines have a special problem with Ethanol blended fuels. Two-Cycle engines function because the oil added to the fuel bonds to the engines metal surfaces and provides barrier lubrication to all the parts requiring lubrication. When Ethanol is added to the gasoline, it displaces the oil and forms a primary bond with the metal surfaces. This bond provides virtually no lubrication and can result in significantly increased wear and even catastrophic failure in a very short amount of time.

Until now the only preventative measures available to tank operators and end users was to try and make sure there was no water in the tank and that vents allowed a minimum amount of airborne water (humidity) into the tank.

Gasohol, E-10, E-20, and E-85 are the terms that refer to gasoline containing Ethanol. For example the most common fuel available today is E10. E-10 is 10% Ethanol and 90% gasoline, while E-85 is 85% Ethanol and 15% gasoline (Note: E-85 is actually E-70 in the winter in cold weather (Northern Tier) states.

Ethanol has less energy (as measure in Btu’s – British Thermal Units) per gallon than does regular unleaded gasoline. This means that the more Ethanol found in fuel the worse your fuel economy will be. You use more gallons of fuel containing Ethanol to go fewer miles.

This poor fuel economy is made worse by other EPA and State requirements for fuels to change seasonally. Until very recently we have used what is known as “Conventional” gasoline (CVG) in the winter and “Reformulated gasoline (RFG) in the summer. The theory is that the lower volatility of RFG will reduce the formation of green house gases. However RFG has lower Btu’s per gallon. RFG together with Ethanol results in a significant mileage penalty. My own vehicle drops about 2 miles per gallon or about 9% when using RFG with Ethanol.

For many years the refining industry used a chemical called MTBE to meet the oxygenate requirements set forth by the EPA. Generally refiners used 15% MTBE and 85% gasoline. However MTBE has now been virtually eliminated in the US due to its carcinogenic compounds and the huge potential problems caused by its pollution of as much as 75% of the ground water in the US and Canada.

This has left Ethanol as the primary additive to meet Federal and State oxygenate mandates.

Further the federal government currently subsidizes Ethanol with a $.51 per gallon tax credit that goes to the refiners or blenders. With E-10 this provides those refiners and or blenders with a $.051 per gallon subsidy on every gallon of gasoline that they sell.

In many cases we have seen gasoline containing more than 10% Ethanol. We test regularly and have seen fuel containing 12%, 13%, and even 14% Ethanol while the pump shows only 10%. Increasing the amount of Ethanol increases the refiner/blenders subsidy and profit while further lowering your fuel economy.

One more concern with Ethanol and RFG or Ethanol and CVG is that Ethanol when mixed with water; they readily form Gums in the fuel system much quicker than gasoline without Ethanol. These Gums coat fuel system components including filters, carburetors, injectors, throttle plates; and will then form varnish and carbon deposits in the intake, on valves, and in the combustion chamber. These deposits can coat sensors and plug catalytic converters.

The good news is that we now have products available to prevent and control Phase Separation and that we can dramatically reduce or eliminate most of the problems caused by Ethanol in Gasoline.

Because of all the problems with Ethanol Blended gasoline’s we will list some specific suggestions and recommendations on how to deal with and resolve many of these problems.

When Phase Separation occurs in fuel tank on a vehicle, boat or other piece of equipment, the tank should be completely drained. The tank should be refilled with good fuel and the fuel line purged prior to restarting the engine.

For Seasonal vehicles and equipment, e.g. boats, personal water-craft, motorcycles, classic cars, ATV’s, RV’s, lawn and garden equipment, gasoline powered generators, and so on, we recommend that you try to use conventional gasoline without Ethanol whenever possible and particularly prior to storage.

In ALL Two-Cycle gasoline engines where there is any possibility that you are using gasoline containing Ethanol we strongly suggest using a full synthetic two-cycle oil in the gas.

In bulk storage tanks where you believe phase separation may have occurred or where you are concerned it may happen. We suggest the use of a modified water finding paste such is made by the Kolor Kut Company. This paste starts out brown, if you dip the tank with a measuring stick with the paste and it turns yellow (even light or spotty yellow), you have significant water dissolved in the fuel, if the paste turns red you have free water.

If you have fuel that has Phase Separated and you have either two or three layers you should arrange to have the tank pumped from the bottom to remove the one or two bottom layers containing the water and or the Ethanol/Water mix. (Note: you should check again with the paste before the technician leaves to be certain that all the Water and Water/Ethanol has been completely removed). You do not need to remove the gasoline. Check with water finding paste after 24 hours. If no red or yellow present then add clean fuel to the tank to working capacity.

If you have specific questions, please contact me here or at: fuelschool@roadrunner.com