Gevo on the Move

Isobutanol company works to convert ethanol production facilities
By Holly Jessen | June 13, 2011

The conversion of a Luverne, Minn., ethanol plant to isobutanol production has begun, and two 50 MMgy Midwest ethanol plants—as yet unnamed—have signed letters of intent with Gevo Inc. “We expect in 2012 to have two operating plants, with a third under construction,” says Jack Huttner, executive vice president of corporate development and public affairs.

A groundbreaking ceremony was held May 31 at Agri-Energy LLC, a 22 MMgy ethanol plant Gevo expects to have retrofitted and fully transitioned to 18 MMgy isobutanol production by June 2012. Because isobutanol has a higher energy content than ethanol, the actual Btu produced will be the same, the company explains. The only new construction required is a separations unit. “Butanol is a little more toxic than ethanol and it inhibits the yeast a little bit, if you don’t separate out the butanol as you ferment it,” Huttner tells EPM. The second unique element of Gevo’s technology is the yeast that produces isobutanol instead of ethanol. Every other operating parameter remains the same. “Corn in, butanol out,” he says. It’s a simple switch to go back to ethanol production. At the end of a run, ethanol yeast replaces isobutanol yeast, and the valve to the separator unit is turned off.” Luverne, though, may not need to switch often. “We’ve pretty much sold out the capacity for butanol so we are not anticipating making ethanol there,” he says, “but we could.”

Gevo has an exclusive engineering and construction alliance with ICM Inc. When the separations facility is complete, another two to four weeks will be needed for finalizing the plumbing and connecting the plumbing and connecting the production facility with the new  unit.    —Holly Jessen