Guidelines for Long Term Fuel Storage of Diesel and Storage Tanks

Fuel prices have faced severe fluctuation in recent times, causing governments and stakeholders to analyze their methodologies about storing fuels. Fuel storage also saw a rise in the storage amounts. This change arose several concerns. How long can you store fuel? How do you resolve chemical instability? How do you prevent microbial activity? What are the appropriate regulations? We look at the answers to such concerns.

• How Long Can Be Diesel Fuel Be Stored? Storage life differs from fuel to fuel – diesel has a different life than ethanol and biodiesel blends. Additionally, storage life is also dependent on certain conditions. The ideal conditions for storing diesel fuel include keeping fuel dry and at a cool temperature (below 70 degrees Fahrenheit). Such conditions ensure storage life between six to twelve months. To extend fuel life beyond twelve months, fuel stabilizers are required.
• Storage Tank Maintenance Regulations. A properly maintained Fuel Storage Tank carries several benefits, the most significant being the prevention of water contamination. Above ground, tanks have open tops which allow rainwater to contaminate the fuel stored. The key strategy to prevent water condensation accumulation in fuel is to minimize the space in the tank. The amount of space needed is dependent on the tank configuration and expansion of fuel based, on its volume. The critical aspect is the maintenance of the structural integrity of the tank.
• Storage Tank Regulations. Storage tank regulations are specially devised to regulate and prevent any adverse impacts on human health or the environment, in case of any damaged or improperly maintained tank. Regulations differ from state to state and types of tanks (under or above ground). Technically, underground tanks are tanks with 10% or more of the structure underground. State regulations include the safety, training, and educating of the workforce, starting from the top management to Class C workers with certified courses like Illinois UST Class C Training. Regulations of leak prevention and corrosion problems differ from state to state. Any storage facility needs careful analysis of the requirements and regulations to ascertain their Return on Investment on such a venture.
• How to Control Stored Fuel Diesel Stability? Microbial activity hinders diesel fuel feasibility as bacteria growth shortens the fuel’s storage life. Biocides and diesel fuel stability treatments are proven methods that prevent the growth of diesel fuel bacteria by eliminating them through biocides. 
  • Biocides have risen in importance to become an essential part of fuel storage facilities. The primary reason behind this rise is that the introduction of the removal of sulfur for ULSD (Ultra low sulfur diesel) makes fuel a lot more vulnerable to microbial activity than what it used to be. Storage fuel stability targets two reactions: Oxidation reactions and acid-base reactions. 
    • Oxidation, as the name illustrates, is what happens when fuel is exposed to oxygen. Oxygen interacts with pre-existing ‘reactive components’ in the fuel. A chain reaction sets off, which reacts in turning the previously healthy molecules in the fuel to unstable reactive molecules. Anti-oxidants are introduced in the fuel to counter this. Anti-oxidants are effective in disrupting the chain reactions that turn stable molecules into unstable molecules. This prevents oxidation from occurring again.
    • Fuel stability treatments affect acid-base reactions the same way. The treatment involves reacting with acid precursors to stop them from reacting further with other fuel agents. This is particularly important in the cases when fuel has been exposed to certain metals, e.g., iron and copper. Fuel exposed to such metals takes as little as a minute to catalyze or ‘accelerate’ such harmful reactions to the fuel. An antioxidant stabilizer, which contains a metal deactivator, is used to blunt and nullify this problem.
  • Biofilms. However, the efficiency of biocides and storage fuel stability treatments are subject to the presence of biofilms. Biofilms are the biological mass produced by organisms present in the diesel fuel storage tank. The mass of such microorganisms can significantly affect how quickly and efficiently a biocide can eliminate or ‘kill’ a microbe present in the diesel fuel.

In a fuel storage tank system, the tank can be re-infected by microbes even after treatment, in case biofilm is present. The solution is to break down the biofilm to enable biocides to penetrate and eliminate the microbial organisms. Depending upon the severity of the biofilm, the storage tank might have to undergo an entire mechanical cleaning to eradicate the presence of biofilms.