Closed-Loop Ethanol Plant
The E3 BioFuels ethanol plant is able to eliminate most of the fossil fuels usually required by ethanol distilleries to heat their boilers, by using biogas from the anaerobic digester to fuel the plant's special boilers.
The closed loop system that E3 is using is very interesting, and it holds tremendous possibility for revolutionizing the future of ethanol and cattle production together.
— Dan Duncan, University of Nebraska-Lincoln
Other ethanol plants heat their boilers with natural gas or even coal, releasing carbon trapped below the surface millions of years ago, with all its pollution. And that fuel is expensive—to make 25 million gallons of ethanol a year, as we do at the Genesis plant in Mead, Nebraska, it would cost $6.5 million to $7.25 million worth of natural gas.
Our plant operates on biogas that we make ourselves, originating with corn, cellulose, and other grain material grown just last year. That avoids the need for expensive fossil fuels, helps keep the air clean and averts global warming.
How ethanol is made
The E3 BioFuels system works along the same lines as a brewery. Grain—in this case, corn—is submerged in liquid. Heat is applied, and the solution ferments, creating alcohol—only here, instead of beer, you get clean-burning, environmentally friendly ethanol.
As the plant converts corn into ethanol, two main by-products are produced: wet distillers grain, or "wet cake," and a milky liquid, "thin stillage." The wet cake is fed to the cows in the next-door feedlot. The thin stillage is piped to the anaerobic digester both to maintain a temperature conducive to anaerobic digestion, and to provide raw material for more biogas. Stand-alone digesters often use much of their energy to maintain proper temperature, whereas the E3 BioFuels digesters benefit from the heating value of the thin stillage, ensuring efficient use of the biogas.
Nothing is wasted, which is more environmental and economical. And no fossil fuels are used, which helps save the environment.