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BRINGING BIO'S FUTURE INTO FOCUS
 

If Robert Brown weren’t already a positive kind of guy, surely the prospect of gasoline at $3 a gallon—and rising—just might put a smile on his face.

No, the director of Iowa State’s Bioeconomy Initiative takes no pleasure from our pain at the pump—he has to buy the stuff too, after all. But as the price of gas moves inexorably higher, the cost of bio-based fuels and related products becomes increasingly competitive. That’s good news not just for Brown’s research program, but also for Iowa’s economy, America’s future energy independence, and the global environment.

With joint appointments in the Departments of Mechanical, Chemical and Biological, and Agricultural and Biosystems Engineering, Brown has a large technological palette from which to paint a picture of America’s energy future. And as his work progresses, the broad imperatives driving his research have borne fruit in the finer brush strokes of technologies that are increasingly viable both economically and scientifically.

The picture came into sharper focus last fall with the completion of a four-year DOE project to process hydrogen from switchgrass in a thermally ballasted gasifier. But it’s not enough simply to manufacture fuels from bio-based feedstocks: producers must take additional measures to add value to byproducts from their feedstocks in order to compete with fossil resources.

While still centered on gasification, Brown’s current project to increase the productivity of bio-based feedstocks goes beyond switchgrass to look at distiller’s dried grain (DGG), a byproduct of ethanol production from which he seeks to extract not just hydrogen but polymers as well, thereby increasing the value of the feedstock.

“It’s interesting conceptually,” Brown says. “A lot of people working in this field have never thought of a project like this, and it’s really captured their imaginations.”

Each ton of corn put through an ethanol distillation process, Brown notes, produces on average equal amounts by weight of ethanol, CO2, and DDG, the latter usually sold as cattle feed for about $75 a ton. However, the prospect of increased ethanol production driving the value of DDG downward has spurred the search for alternative markets for the byproduct to keep ethanol production profitable.

“We’re looking at taking DDGs, which are only worth about 3 and 1/2 cents per pound,” Brown says, “and converting them into polymers worth $1 a pound.”

According to Brown, a DDG-based polymer would potentially have wide market appeal. For example, using a caustic solution to dissolve bio-based polymers in lieu of incineration, hospitals generating large amounts of medical waste could significantly reduce disposal costs. Likewise, the U.S. Navy has expressed its interest in waste materials that can dissolve harmlessly in the ocean.

Brown notes that the polymer as currently produced in Europe from sugars and waste oils sells for $3 a pound. By instead converting DDGs to both polymers and hydrogen, Brown’s system has the potential to undercut European price benchmarks by nearly two-thirds.

“We hit the (DOE) target prices for hydrogen in our original switchgrass gasification project.” Brown observes. “Now we want to see if we can make these polymers at an attractive market price using those target prices for hydrogen.”

By developing technologies to extract a variety of marketable secondary products from biological feedstocks, Brown maintains, fuels such as biodiesel and biomass-generated hydrogen assume far more competitive positions vis-à-vis fossil sources. However, since the infrastructure for manufacturing, transporting, and utilizing these products has yet to come online, the technologies that enable them have been, in a sense, merely “academic.”

No longer, says Brown.

“When gas prices were low, people would ask why we were doing this,” Brown recalls. “I’d reply that it’s a kind of insurance policy—we may never need it, but if we do, the technology would be available. Today, it’s increasingly looking like a policy we’re going to cash in on.”