Chemical Engineering October 2011 - 16

Dewatering enzymes boost ethanol production efficiency
ChementatoR
A
technique that improves the efficiency
of ethanol plants by lowering the cost of
dewatering the byproduct stillage (a slurry
of corn solids and water) from the fermentation
process has been developed by scientists
at the U.S. Department of Agriculture's
(USDA) Eastern Regional Research Center
(Wyndmoor, Pa.; www.ars.usda.gov). The
process has been demonstrated at full scale
in a commercial plant operated by Center
Ethanol Company (CEC; Sauget, Ill.).
CEC produces 50-million gal/yr of ethanol
from corn and 172,000 ton/yr of dried
distillers grains with solubles (DDGS), used
for animal feed. Like other ethanol producers,
CEC separates the ethanol from the solids,
which are then dewatered sequentially
by centrifugation, evaporation and drying
to obtain DDGS.
The USDA procedure improves dewaRecoveR
co2 (Continued from p. 15)
rapid cycling. Grace is working with
zeolite materials, such as 13X and 5A,
says Harding. Another challenge is to
tering by adding enzymes to the fermentation
process. In the tests, performed on
six 750,000-gal fermenters, the researchers
added a cocktail of commercial cellulase
enzymes supplied by Genencor
(Rochester, N.Y.) using 1 lb of enzymes
per 1,000 lb of corn. The enzymes break
down the fibrous material (mostly hemicellulose)
in the solids, thereby disrupting
their water-binding ability, says scientist
David Johnston.
In the tests the enzymes improved centrifugal
water recovery by 14%, with a corresponding
14% reduction in the gas requirement
for the dryer. Johnston says the
procedure requires essentially no modification
to the process. He adds that Genencor
and another enzyme supplier are now working
on enzyme preparations specifically designed
for this application.
develop equipment that has high-speed
valves. " Existing valves can be operated
at that speed, " he says, " but we need
more robust valves and may have to
change the geometry of the equipment. "
(Continued from p. 13)
solar module from Konarka with
a photoreactive polymer that,
when dissolved, can be applied
to various substrates.
in addition to their integration
into steel facades, the organic
cells will also be integrated
into glass facades. together
with bischoff glass technik
ag (bretten, german; www.
bgt-bretten.de), Konarka is
planning to develop (within the
scope of a pilot project) glassglass
modules for building
integration. the connections for
the modules come from lapp
Kabel (Stuttgart, germany;
www.lappkabel.com), and the
modules will be characterized
by the Fraunhofer institute
for wind and energy System
technology (bremerhaven;
germany; www-cwmt.cwmt.
fraunhofer.de).
Grace's partners are Battelle (Columbus,
Ohio), Catacel Corp. (Garrettsville,
Ohio) and the University of South Carolina
(Columbia, S.C.), which has expertise
in PSA.
Our ChemiCal SOlutiOn.
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heavy-duty positive
displacement blowers,
long known for their
quality, dependability
and outstanding performance,
have specially designed features
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16 ChemiCal engineering www.Che.Com oCtober 2011
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Chemical Engineering October 2011

Table of Contents for the Digital Edition of Chemical Engineering October 2011
