Fuel Contamination

free water in offf road diesel

Fuels are quite different from those a decade ago. There are numerous problems associated with the quality of fuel. Diesel and gasoline are not problems in and of themselves. However, a combination of factors have contributed to a whole host of serious and potentially dangerous concerns. Between 2004 and 2006, the EPA mandated the reduction of sulfur in fuel and the addition of biofuels (ethanol and biodiesel). These along with the removal of lead produced more than a few unintended consequences. Many in the petroleum industry are trying to determine the proper response to these unforeseen problems.

Before 2004 it was not uncommon for fuel to have a 5 or 6 year shelf-life. According to the most recent research, fuel begins deteriorating before it ever reaches the end user. In fact, if water is present, it can degrade by as much as 95% within 30 days of refining.

Current fuel studies show that the fuel coming out of terminals have minimal biocide, leaving them vulnerable to microbial contamination. Additionally, if fuel is exposed to other contaminants it will exacerbate an already serious problem. Water exposure, cross-contamination and the addition of biofuel contribute to the problem.

Water contamination can happen at any time during the transportation and storage of fuel. During barging and shipping, water exposure is a constant problem. Even when pumped off, some amount of water remains in the fuel. Transport truck delivery also provides a potential for water to enter the fuel. Driver error or incompetency can lead to water entering the fuel. It is not uncommon for drivers to leave tanker access ports open, allowing water and contaminants to enter the fuel. Another common mistake made by drivers occurs when dropping fuel. Standing water often enters the fuel tank when the driver makes the delivery. Many of the most egregious errors take place during seasonal weather events.

Once delivered, water intrusion can occur both naturally and systemically. Naturally, water enters fuel through the process of condensation. Temperature differences or variances change the humidity levels in the fuel system producing condensation. Over time, condensation will settle and become measureable. However, while it is suspended in the fuel it is virtually undetectable. Systemically, water can enter into the fuel through leaks and weaknesses within the fuel system itself. Often leaks are small and water creeps in virtually undetected until the damage is done.

When water enters conventional fuel, it settles, generally dropping out of the fuel at a rate of one foot of fuel per hour. That means a tank with 10 feet of fuel will require 10 hours for the water to settle. Unfortunately, most fuels contain a bio-mix of either ethanol or biodiesel. Both are considerably more water soluble than conventional fuel and contain more suspended water in the fuel.

Ethanol is hydrophilic – it loves water. In ethanol enriched gasoline up to .5% water can be suspended in the fuel before the water begins to drop out. This process is called phase separation. When the water drops it takes with it the ethanol. The ethanol and water mixture is the perfect breeding ground for microbes, the most common of which is “acetobacter.” This bacteria is associated with the creation of acetic acid. When ethanol and water bond chemically, they create a perfect environment for the acetobacter to reproduce at an alarming rate.

Regulations allow up to 5% biodiesel to be mixed with conventional diesel without any labeling or notification. As with ethanol, biodiesel is very soluble. According to the EPA in its most recent study, “Diesel blended with biodiesel can hold in solution more water than diesel without a biodiesel component. This means more water is likely arriving in USTs entrained in fuel today since biodiesel is more common in diesel than prior to 2007.”

Both ethanol and biodiesel are microbial food sources. Most of the microbes affecting fuel require a water interface to multiply. The combination of a readily available food source and interface make today’s fuels difficult to maintain. Microbial growth has become common and the corrosion problems associated with them are very serious.

Additionally, most carriers practice switch loading – transporting gasoline and diesel in the same trailer or truck compartment – contributing to the problem through cross-contamination. The EPA discovered 90% of diesel tanks tested contained ethanol contamination suggesting that cross-contamination is the norm. Recent research confirms that the ethanol contamination in diesel is likely the main cause of corrosion in fuel systems and engines. Research asserts, fuel system corrosion was not a major problem until ethanol was in common use. Ethanol cross-contamination in diesel and the serious corrosion in fuel systems lends to this assertion.

All of this adds up to the need for a fuel quality management program. If you own a fuel system, fuel management is a reality.

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