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Researchers began heating biomass without oxygen to 932° F for a couple seconds at a time. The process produces gas that's used to fuel the processing operation, a solid called char that's used as fertilizer, and a liquid called bio-oil. About 30% of the biomass is fractionated into usable bio-oil; the rest, which isn't as viscous, is used in applications that include biodiesel and pharmaceuticals.
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Iowa State University engineering professor Chris Williams estimates that a biorefinery that converts 600 to 800 tons of biomass per day would cost $30 million. Photos: Iowa State University

Back in Iowa, William's 50-ton/day facility, built by Canadian company Advanced BioRefinery Inc. to produce oil from corn stalks and leaves, went online west of Des Moines this month using the same type of equipment used to make heating fuel from biomass. Another Canadian company, Dynamotive Energy Systems Corp., operates the first commercial production facility, and recently announced plans to operate plants in China and Latin America.

Williams believes the market ultimately could support more than two dozen plants, adding that the low-viscosity, dark brown oil has the potential to become one of Iowa's more profitable exports. “The same opportunity doesn't exist in Arizona, for example, so the Upper Midwest and East Coast could be prime locations for these plants,” he says.

AN OPTION AHEAD OF ITS TIME?

The Federal Highway Administration (FHWA) has one major concern: performance characteristics.

“We promote environmentally friendly materials, but they have to be as good as or better than existing materials,” says John D'Angelo, asphalt team leader in the agency's Office of Pavement Technology. The agency hasn't researched plant-based binders but expects to monitor the results of the Iowa State project. If the bicycle path holds up, the agency likely will want to learn more about the process.

FHWA wants to see more demand, but road builders aren't using the product because of the lack of empirical data. “Even if it's a great product, if it can be made only in small quantities it's not useful for our purposes,” he says of an industry that produces and uses 35 million tons of asphalt annually.

The agency needs to be convinced of the binder's compatibility with existing asphalt, durability, and life-cycle costs. That leaves companies like Colas, whose U.S. headquarters is in New Jersey, in limbo.

“The downside is that because it's a new technology it's expensive,” says Larry Galehouse, director of the National Center for Pavement Preservation. “Nobody knows when it will be a viable option.” But with the hot-mix industry warming up to warm mixes, he points out, anything is possible.

Williams is even more optimistic. “We're reducing greenhouse gases, and that's going to be worth something pretty soon,” he says. “If things look good here in the pilot plant facility, we're looking at a five-year horizon for building out here in Iowa.”