More fuel from the cob

Everyone understands the benefits of getting more from less — especially regarding energy production. America is seeking a reliable, domestic fuel base and numerous sources have been tested and employed, including corn ethanol.

Corn ethanol is a clean-burning fuel additive made from corn-kernel starches and is regularly blended with petroleum to diversify the fuel supply and decrease America’s dependence on foreign oil to offset the cost of standard gasoline.

The ethanol sector is one of the corn industry’s chief markets, and the future of the U.S. ethanol industry depends on its ability to increase yields, be competitive with fossil fuels and fill a growing need for energy independence.

Ethanol production is accomplished either after a wet or dry milling process, though dry milling is most common and is explained as follows: (National Renewable Energy Laboratory)

“Corn grain is milled then slurried with water to create ‘mash.’ Enzymes are added to the mash and this mixture is then cooked to hydrolyze the starch into glucose sugars. Yeast ferment these sugars into ethanol and carbon dioxide and the ethanol is purified using a combination of distillation and molecular-sieve dehydration to create fuel ethanol. The byproduct of this process is known as distiller’s dried grains and solubles (DDGS) and is used wet or dry as animal feed.

An emerging technology called hydrodynamic controlled-flow cavitation is advancing the capabilities of ethanol production.

According to an Ethanol Producer Magazine story, hydrodynamic cavitation is the process of “passing a liquid through a constricted channel at a specific velocity. The formation and implosion of bubbles in the liquid releases tremendous localized energy in the form of shockwaves. Controlled-flow cavitation technology controls the location, size, density and intensity of the implosion of bubbles in the zone to create optimum process conditions”.

The following diagram from a Ohio State University Ohio Agricultural Research and Development Center (OARDC) story illustrates how cavitation "liberates" more starch from milled corn before it's fermented and distilled to ethanol (courtesy of Arisdyne Systems Inc.).

"Corn grain containing between 70 and 73 percent starch is distilled to ethanol," said Fred Michel, an OARDC biosystems engineer. "While the recovery of starch in commercial ethanol plants is high, as much as 4 percent of the starch remains in the byproducts after fermentation. We are targeting that 4 percent from the use of cavitation."

With support from a $1 million Third Frontier grant awarded in 2008, OARDC has partnered with Arisdyne Systems Inc., a Cleveland-based company, to test cavitation technology:

  • The project generates 13 Ohio jobs
  • Cavitation helps increase ethanol yield by 2 to 3 percent
  • A 3 percent yield boost can increase the revenue of a 100-million gallon ethanol plant by approximately $3.75 million annually
  • If the entire U.S. ethanol industry (13.2 billion gallons in 2010) were to use cavitation, the revenue increase could reach at least $500 million annually
“We need to be looking at yield enhancement as a top priority,” said Fred Clark, executive vice president for Arisdyne.

Yield enhancement has always been and will continue to be a major industry goal for the profitability of U.S. corn. Cavitation has the promise to improve corn farmers’ financial success and the energy security of the country simultaneously.

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