August 4th, 2011
Econintersect: Rolling and floating transport facilities for ethanol have become overloaded as production swelled to 13 billion gallons in 2010. One proposal to relieve that stress, using gas pipelines, has run into an unexpected roadblock. It has been found that stainless steel, the material from which the pipelines are constructed, is attacked by a bacteria that thrives in ethanol. Resaerchers at the NIST (National Institute of Standards and Technology have reported this week that the effects are dramatic: stress crack growth could be observed in periods of time of ten days and less.
Follow up:From RD Mag:
At DOD Corrosion Conference 2011 this week in La Quinta, Calif., NIST researchers presented new experimental evidence that bacteria that feed on ethanol and produce acid boosted fatigue crack growth rates by at least 25 times the levels occuring in air alone.
The NIST team used a new biofuels test facility to evaluate fatigue-related cracking in two common pipeline steels immersed in ethanol mixtures, including simulated fuel-grade ethanol and an ethanol-water solution containing common bacteria, Acetobacter aceti. Ethanol and bacteria are known to cause corrosion, but this is the first study of their effects on fatigue cracking of pipeline steels.
"We have shown that ethanol fuel can increase the rate of fatigue crack growth in pipelines," NIST postdoctoral researcher Jeffrey Sowards says. "Substantial increases in crack growth rates were caused by the microbes. These are important data for pipeline engineers who want to safely and reliably transport ethanol fuel in repurposed oil and gas pipelines."
Ethanol, an alcohol that can be made from corn, is widely used as a gasoline additive due to its oxygen content and octane rating. Ethanol also can be used as fuel by itself in modified engines. The NIST tests focused on fuel-grade ethanol.
The old saying about drinking says "there's many a slip twixt the cup and the lip." When it comes to alcohol as fuel ia appears there's many a slip twixt the cob and the trip.
Source: RD Mag