Understanding and Preventing Water in Fuel Storage Tanks

Water in fuel tanks is a concern for all travel plaza and truckstop operators, but the fuel itself is not the cause of water issues in fuel tanks. Storing fuel — be it petroleum diesel, renewable diesel, biodiesel or gasoline— in a clean, dry tank is critical. In fact, water is the common denominator for two major issues with fuel storage: microbial contamination and corrosion. Let’s address these one at a time, and then discuss a few tips to help.
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Understanding and Preventing Water in Fuel Storage Tanks
 

Water in fuel tanks is a concern for all travel plaza and truck stop operators, but the fuel itself is not the cause of water issues in fuel tanks. Storing fuel — be it petroleum diesel, renewable diesel, biodiesel or gasoline— in a clean, dry tank is critical. In fact, water is the common denominator for two major issues with fuel storage: microbial contamination and corrosion. Let’s address these one at a time, and then discuss a few tips to help.

Water in the Tank
No fuel can create water. Also, dissolved water isn’t the issue — free water is the problem. If there’s a way for free water to get into any fuel tank, it will. Once a fuel tank has free water in it, it is likely to cause issues, one of which is microbial growth. Sources of free water include rain and condensation from combinations of warm days and cool evenings, or warm air above ground and cool underground temperatures.

Microbial Contamination
Free water is the root cause for microbial activity in tanks. The outside world is full of microbes in the air, soil and surface water, which means some microbes will always be present in an underground fuel tank. But keep in mind that presence alone doesn’t cause the problems — the problems occur when microbes are allowed to reproduce and flourish. This requires a free water layer in the bottom of a tank and time for the microbial population to grow unchecked.

Corrosion
Excessive microbial growth can contribute to corrosion in a storage tank (remember, this requires the presence of free water). Any kind of fuel can act as a feedstock for these microorganisms. They live in the water layer, eat fuel molecules and some can excrete corrosive molecules such as acetic acid. Corrosive molecules can affect tank walls, pipes, fittings and pump parts, and can cause rust to accumulate in dispenser filters.

Five Fuel Storage Tips
Clean, dry tanks are important to ensure your customers’ systems run properly. Here are five tips to keep your tanks clean and minimize the chances of water getting into the tank.

  1. Take a dispenser sample at least every 30 days and, ideally, immediately after a fuel delivery when the tank bottoms have been disturbed.
  2. Periodically pull samples from the dead bottom of the tank and inspect for free water and hazy fuel.
  3. Evaluate your system for potential points of entry for water and monitor regularly.
  4. Consider automated water-detection systems if possible to provide continuous monitoring in addition to periodic sampling.
  5. If free water problems persist for more than a week, consider removing water and wet fuel from the bottom of the tank and treating the tank with a biocide additive.

Having a fuel supplier who can educate you on proper storage and continued monitoring is another key to success. The Renewable Energy Group technical services team is always ready to help and can be reached at 1-888-734-8686, or you can email me at steve.klein@regi.com to discuss.

Renewable Energy Group is leading the energy industry’s transition to sustainability by transforming renewable resources into high-quality, cleaner fuels. REG is an international producer of cleaner fuels and North America’s largest producer of biodiesel. REG utilizes an integrated procurement, distribution and logistics network to operate 13 biorefineries. REG is meeting the growing global demand for lower-carbon fuels and leading the way to a more sustainable future. Learn more about Renewable Energy Group.

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