Beyond biofuels, scientists seek uses for byproducts
By Hillary Rosner
Published: August 7, 2007
DENVER: The baking tins and muffin cups lining the countertops in a
corner of Ronald Holser's cluttered laboratory were filled with curious
substances resembling angel food cakes and loaves of bread.
But Holser did not advise eating them. The concoctions were prototypes
for biodegradable weed barriers and sticky films intended to hold grass
seeds on the ground long enough to germinate.
If Holser, a research chemist, and his colleague Steven Vaughn, a plant
physiologist, are successful, they will not only have found ecologically
friendly ways to fight weeds and grow grass. They will have found
innovative uses for a byproduct of biodiesel production, glycerol. This,
in turn, could help transform the biodiesel industry into something that
more closely resembles the petroleum industry, in which fuel is just one
of many profitable products.
"Just like petroleum refineries make more than one product that are the
feedstock for other industries, the same will have to be true for
biofuels," said Kenneth Reardon, a professor of chemical and biological
engineering at Colorado State University in Fort Collins, Colorado.
"Biorefining is what the vision has to look like in the end."
Glycerol, for instance, is now used in products from food to soap to
dynamite. But as biodiesel production in the United States has
escalated, the market for glycerol has become oversaturated. If
scientists like Holser, who works at the United States Department of
Agriculture's research center in Athens, Georgia, and Vaughn, who works
at the department's National Center for Agricultural Utilization
Research in Peoria, Illinois, can expand the number of valuable uses for
the syrupy liquid, biodiesel makers could sell their glycerol instead of
paying someone to haul it away.
"Every week I get at least one or two calls from biodiesel producers who
have all this glycerol and don't know what to do with it," Holser said.
Nor is glycerol, also called glycerine, the only byproduct of biofuel
production that is the subject of experiments. Scientists are also
looking at profiting from the leftovers in the production of corn
ethanol and cellulosic ethanol, produced from materials like
switchgrass, corn husks and prairie grass.
Some researchers like Holser are simply trying to find new uses for the
regular byproducts of biofuels - distiller's dry grain from corn ethanol
and lignin from cellulosic ethanol.
Other researchers are focused on developing new technologies and
processes that could yield different, more valuable, byproducts. And
still others are placing their bets on "biorefineries."
In the foothills of the Rocky Mountains, not far from the Coors brewery
in Golden, Colorado, PureVision Technology, is making lignin. A natural
polymer that helps provide strength and rigidity in plants, lignin makes
up 15 to 25 percent of most plants. It is also a byproduct of the
production of cellulosic ethanol. Most plans for cellulosic ethanol
processing call for burning the lignin to generate steam and heat to run
the process. As a fuel, lignin is worth around $40 a ton.
PureVision has devised a way to make a different form of lignin - one
whose molecular composition could make it an attractive material for a
variety of industrial products like glues, sealants and detergents.
Ed Lehrburger, PureVision's founder and chief executive, said he
believed his lignin could sell for $300 a ton or more. Lehrburger said
his company was currently collaborating with a wood and paper products
manufacturer that was interested in using the lignin for a biobased glue
for its laminates, plywoods and other products.
"Lignin is going to be one of the big drivers of the switch from
oil-based to biobased products," Lehrburger predicted.
The price of glycerol, currently around 20 to 50 cents a pound, could
drop as low as 5 cents a pound as biodiesel production increases.
"What we see," said Kraus, "is an opportunity to make something that
might cost 80 cents a pound. So you can see a larger profitability for
the overall operation."
In another lab at Iowa State, Robert Brown is using distiller's dry
grain - a main byproduct of corn ethanol that is currently largely sold
as animal feed - to produce hydrogen and a biopolymer called PHA. Brown
hopes his version, which is biodegradable, could be used for surgical
gowns and gloves that must now be disposed of as medical waste.
"Critics of corn ethanol like to say the process isn't very efficient,"
Brown said. "Part of that is because your products aren't just fuel."
Finding other high-value applications, he added, allows producers to
"justly say, this is not a waste stream, it adds to the profitability of
the plant."
Interest in the biorefinery model is not limited to research scientists
and start-up companies. Archer Daniels Midland is expanding some of its
wet mill plants, which already churn out both ethanol and a variety of
other corn-based materials like high-fructose corn syrup, amino acids
and sorbitol, to make industrial products. It has begun making propylene
glycol, a widely used compound, from glycerol.
"The idea of a refinery, in part, is to have a multitude of products out
the back end," said Mark Matlock, senior vice president of research at
the company in Decatur, Illinois. "As petroleum prices increase and we
try to become more independent with regard to energy and petroleum in
general, there are other opportunities that come up for industrial
chemicals as well as fuels."
But despite the myriad of uses for byproducts, the biorefinery model is
more difficult than it may seem.
"The dream is the multiproduct biorefinery," said Jim McMillan, manager
of biorefining process research and development at the National
Renewable Energy Laboratory in Golden, Colorado.
"The challenge is that the market for the fuels is like two orders of
magnitude bigger than for even a fairly big chemical" that could be
produced alongside the fuel.
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Check for earlier Pacific Biofuel posts: http://pacbiofuel.blogspot.com/
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