Mercer Energy licenses HydroMill process

By Ron Kotrba | November 13, 2007
Mercer Energy Inc., owner of a 50 MMgy ethanol plant project in west central Ohio, is licensing the use of Corn Value Products LLC's (CVP) HydroMill modified wet-milling process.

Ryan Schwieterman, president and CEO of Mercer Energy, said the HydroMill process is different than traditional wet milling because it doesn't require sulfur dioxide in the steeping process before corn fractionation. "Sulfur dioxide disperses the protein matrix that encapsulates the starch granules via the cleavage of disulfide bonds," wrote Oliver Daily of the USDA Agricultural Research Service in a government report investigating alternative steeping methods for wet milling. Schwieterman told EPM that the CVP process utilizes enzymes rather than sulfur dioxide, but he couldn't say which ones.

According to CVP, the modified wet-milling process holds several advantages over the various dry-fractionation processes competing for a foothold in the ethanol industry based largely on dry milling whole corn. Compared with wet milling, dry fractionation is prone to higher starch losses, which result in lower ethanol yields per bushel of corn and increased logistics costs per unit of production, according to CVP. However, Ethanex Energy Inc. is developing three projects that will use Buhler AG dry-fractionation equipment. It claims testing done in Sweden and at the National Corn-to-Ethanol Research Center in Illinois indicated that its starch loss was kept to a minimum of 2 percent to 4 percent over conventional dry milling.

Schwieterman said the trademarked HydroMilling process cleanly separates the germ and fibrous pericarp from the starch into additional trademarked coproduct streams: NeutraGerm for edible oil; ProBran fiber for pet or animal feed; and Glutenol, a concentrated protein feed for livestock or pets. Mercer Energy plans to sell its raw germ to a food processor, which would then purify the oil off-site. The project has received its air and water permits from the state. With no sulfur dioxide used in steeping the corn and no oil passing through the drying process, Schwieterman said the environmental impact and plant emissions will be lower than most similarly sized U.S. ethanol plants. Mercer Energy's modified wet-mill ethanol plant costs more to build than a conventional dry mill, but Schwieterman said the cost is a "notch less than a traditional wet mill." Mercer Energy anticipates breaking ground in the first half of 2008. "With margins being as difficult as they are right now in the ethanol industry, we believe there will be an advantage to using the HydroMill process," Schwieterman said.