Sustainable Biofuel from Cheap Sugar?

09/29/2011 |


Credit: Naomi Friend/Iowa State Bioeconomy Institute

Are next generation sustainable biofuels on the way courtesy of cheap sugar?  Walking into the office of Iowa State University’s Robert C. Brown reveals a small vial of brown, sweet-smelling liquid.

It looks like something you could pour on your pancakes," says Brown. "In many respects, it is similar to molasses."

Brown, in fact, calls it "pyrolytic molasses."

That's because it was produced by the fast pyrolysis of biomass such as corn stalks or wood chips. Fast pyrolysis involves quickly heating the biomass without oxygen to produce liquid or gas products.

Those sugars can be further processed into biofuels. Brown and other Iowa State researchers believe pyrolysis of lignocelluslosic biomass has the potential to be the cheapest way to produce biofuels or biorenewable chemicals.

Brown lays out the highlights of these thermochemical development processes:

Increase the yield of sugar from fast pyrolysis of biomass with a pretreatment that neutralizes naturally occurring alkali that otherwise interferes with the release of sugars

Prevent burning of sugar released during pyrolysis by rapidly transporting it out of the hot reaction zone

Recover sugar from the heavy end of bio-oil that has been separated into various fractions

Separate sugars from the heavy fractions of bio-oil using a simple water-washing process.

"The Department of Energy has been working for 35 years to get sugar out of biomass," Brown said. "Most of the focus has been on use of enzymes, which remains extremely expensive. What we've developed is a simpler method based on the heating of biomass."

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