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December 09, 2014
Storing ethanol in your tank? Think wisely
By Amanda Czepiel, JD, Senior Managing Editor

At the first annual New England UST and Shop-Fabricated Storage Tank Conference in Worcester, Massachusetts, sponsored by the National Institute for Storage Tank Management (NISTM), Marshall Mott-Smith, President of the Mott-Smith Consulting Group, had a clear message: Putting alternative fuels in storage tanks is risky business, but because biofuels are here to stay, storage tank owners and operators need to create solutions for the corrosion that results from storing such liquids.


In his presentation, “Emerging Solutions for Biofuel-Induced Corrosion for ASTs and USTs,” Mott-Smith explained that ethanol’s popularity is a result of a combination of the assumptions that it burns cleaner and reduces air pollution, reduces reliance on foreign oil and augments the U.S. fuel supply, stimulates the nation’s economy, and is a “green” fuel.

However, those assumptions are incorrect, according to Mott-Smith. In reality, ethanol does not burn cleaner and actually leads to an energy drop off and competes with food crops, which in turn increases food costs. But for the oil and gas industry and those who manage tanks, ethanol is an even bigger management problem because it is incompatible with fiberglass tanks; it loves to eat soft metals, rubber, and plastics; and has a scouring effect on tank systems that causes corrosion.

These characteristics result in more frequent dispenser filter changes and the destruction of pumping infrastructure. But, thinking that ethanol and other biofuels are just a trend would be false hope, says Mott-Smith.

Therefore, tank owners and operators must take precautions before adding a high percent ethanol blend to a storage tank. Such precautionary steps include:

  1. Verify that a dedicated fuel path is compatible with the percent of ethanol to be stored and dispensed.
  2. Make sure that the following equipment, components, and materials are compatible with the fuel stored:
    • Fill pipe/drop tube
    • Auto shutoff or overfill valve
    • Tank
    • Internal lining material used on relined tanks
    • Submersible pump and pump impeller
    • Gaskets, bushings, couplings
    • Line leak detectors
    • Leak detection equipment (ATG probes, floats, sump sensors)
    • Piping material
    • Pipe adhesives/glues
    • Flex connectors, grommets
    • Filters
    • Dispensers
    • Hoses (including breakaway couplings or fittings)
    • Nozzles
    • Spill containment and sumps
  3. Ensure that there are no water intrusion problems.
  4. Make certain that all fittings and connections at the top of the tank are tight and that all sump and spill containment covers prevent water from entering.
  5. Clean all tanks to remove any sludge.
  6. Identify all fill pipe and access covers.