It may soon cost just a penny a gallon to add a lot of value to a gallon of ethanol. Two Iowa State engineers have invented a process that reduces the cost of purifying ethanol into food-grade alcohol by 98%.

Removing organic impurities from ethanol is not such a departure from the professions of these two inventors. Jacek Koziel and Hans Van Leeuwen use these same technologies to remove ag compounds from air and wastewater.

Koziel is assistant professor of Air Quality Engineering and Livestock Odor at Iowa State University. His partner in this venture is Hans Van Leeuwen, Iowa State professor of Civil, Construction and Environmental Engineering and vice president of Mell03z, a Cedar Rapids startup firm. The firm holds two patents that improve the quality of alcoholic liquors.

“We use ozone to oxidize undesirable compounds, and then filter the ethanol with granular activated carbon filters,” says Van Leeuwen. He's already used the process to purify wastewater successfully. This uses a small fraction of the energy required by multiple distillations, the conventional purification process.

Although ethanol and alcoholic spirits are chemical twins, the latter result from multiple distillations to catch impurities contaminating taste and smell. The colorful part of this research is the “sniff board” used to quantify things like the rotten egg smell. For example, sulfur-based compounds in fuel ethanol often impart a “barnyard smell and taste,” says Koziel. These mercaptan compounds resemble the rotten-egg smell added to natural gas as a tracer. “There are low levels of sulfur in all plant material, so this isn't surprising,” he adds.

The U.S. market for food-grade alcohol is 250 million gallons annually, says Van Leeuwen. This is small compared to the 4.6 billion gallons of ethanol produced annually in the U.S., but represents another market for farm crops. The professors' new technology would be inexpensive to retrofit on existing ethanol plants, he says.

Adding value to farm crops was the basis of Koziel's original $79,900 grant from Iowa's Grow Iowa Value fund.

The daunting terminology is actually straightforward to grasp. Bubbles of ozone gas burn off (oxidize) undesirable compounds, and combine with others to be screened out by the carbon filter. The degree and combination of these two processes is the essence of their patent.

While the technology is relatively simple, the regulatory hurdles involved in food-grade alcohol are not. Spirits manufacturing requires a higher standard of purification, and of capital investment, says Nathan Fields, National Corn Growers Association director of research and business development. “If these researchers can reduce the cost to 1¢/gal., it would be a great way ethanol producers can add value,” he says.

Koziel and Van Leeuwen have been approached by a few large alcohol companies interested in their new experimental process.

Midwestern Vodka

One ethanol plant that has cleared the bonding and regulatory hurdles of food-grade alcohol production is the Chippewa Valley Ethanol Co., Benson, MN. Its wholly owned subsidiary, Glacial Grain Spirits, produces Shakers Vodka. Its fuel ethanol is made from corn, but its vodka is distilled from wheat and rye.

The continuous distillation process is powered by natural gas, and general manager Bill Lee finds the potential alternative interesting. “The vodka is a small percentage of what we do, yet it would be very significant if we could reduce ethanol purification costs by the magnitude delivered by the Iowans' new technology,” he says.

The 45-million gallon ethanol cooperative began 10 years ago. It's the only farmer-owned ethanol company in the beverage business.