Tons of distiller's dried grains being held in storage at an ethanol plant. Click the image for more information about it.

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Ethanol Byproducts Pelletized

By Don Comis
June 25, 2007

One hundred percent of distiller's dried grains with solubles (DDGS), a byproduct of ethanol production, can be pelletized without adding a binding agent or anything else, according to Agricultural Research Service (ARS) scientists and cooperators.

ARS agricultural engineeer Kurt Rosentrater has turned DDGS from corn-based ethanol production into high-quality pellets using processing equipment at a commercial feed mill. And the heating used in pelletizing did not harm the high-protein, low-starch nutrient content. Rosentrater is at the ARS North Central Agricultural Research Laboratory, Brookings, S.D. He does this research with colleagues at ARS and at nearby South Dakota State University.

Cattle feed is currently the primary outlet for distiller's grain. But other livestock such as swine and poultry can also eat it. To date, there are no commercial DDGS pellets available for livestock, which limits the byproduct’s use in rangeland settings. DDGS is the protein, fat, fiber, unconverted starch and ash left over after ethanol production.

Fish raised for food in the growing aquaculture industry eat pelletized feed, but those pellets contain commercial fish meal as a protein source, not the less-expensive distiller's grain. Rosentrater is experimenting with adding soy and corn flour to distiller's grain to produce pelletized feeds, to see how far he can reduce the fish meal—or if he can eliminate it entirely.

This pelletizing work also promises to solve a growing problem of product deterioration—as well as hardening and caking problems during shipping and storage, which can clog the various chutes and bins that DDGS flows through. With an increasing supply of the byproduct, ethanol plants have to ship it greater distances to reach markets.

South Dakota, one of the country's biggest ethanol-producing states, expects to produce a billion gallons of ethanol to fuel vehicles next year—about the entire nation's production in 1999. Today, nationwide ethanol production is more than five billion gallons a year, and that amount will increase as new plants come online.

Ethanol plants are spreading outside of the Corn Belt, with plants now in New York and California, for example.

ARS is the U.S. Department of Agriculture's chief scientific research agency.