With the supply of crude oil depleting, traditional fuels blended with ethanol or biodiesel derived from non-petroleum sources are rising. And the best way to transport, store and dispense these new fuels is through steel tanks. Even the military now uses steel for its ethanol fuel tanks. It’s the best material to contain today’s biofuels. It’s been proven that steel is suitable with high-percentage ethanol and biodiesel combinations.
In 2010, the US Department of Energy conducted a study where steel coupons were evaluated for corrosion. These were immersed in ethanol blend fuels with some contaminants to imitate real settings. Results showed that mild steel and stainless steel were corrosion-resistant with no observed effects on metallic parts or equipment.
In another study, steel corrosion rates for E30, E70 and E95 were “below detectable limits.” In the research made by the Southwest Research Institute (SwRI), they found no serious traces of corrosion and no pits formation when steel was exposed to petroleum and/or biodiesel combinations.
Organizations such as Underwriters Laboratory (UL), SwRI, API and Steel Tank Institute (STI) set standards for fuel tanks. UL expressed that in its general listing for flammable and combustible liquids, high-percentage blend ethanol fuels such as E85 is included.
In addition, NFPA’s Flammable and Combustible Liquids Code dictates that above-ground fuel storage tanks must be made of steel.
Fiberglass storage tanks fabricated prior to 1992 may not be able to handle E85 says the American Coalition for Ethanol. Modifications were required for FRP tanks made after 1992 to hold higher ethanol percentage fuels. In comparison, composition of steel tanks has no significant changes for quite some time. That is why E85 has been successfully stored in carbon steel tanks for over 25 years.
Below is a list of fuel blends for steel storage.
STI authorized tank types such as sti-P3®, ACT-100® and ACT-100-U®, and Permatank®. STI stated in its Statement of Compatibility that these tanks and all steel tanks are acceptable for use with all fuel blends meeting ASTM standards.
Guidance on Compatibility of Underground Storage Tank Systems with Biofuel Blends was issued by EPA in July 2011 with the following requirements:
According to EPA, these manufacturer approvals should be in writing containing an affirmative statement of compatibility for the range of fuels. And these approvals must be presented by the manufacturers themselves. Letters of Compatibility are posted at www.steeltank.com.
Here are some facts on steel and alternative fuels: