Assessment of Conversion Technologies for Bioalcohol Fuel ...

developed by CBE, is used to separate the cellulose from the lignin from the sodium
silicate. The filtered cellulose is washed with a washing centrifuge. A belt-press filter
is used to remove water to 70-80% cellulose. The cellulose is hydrolyzed with acid
hydrolyzing enzymes. The sugars, generated from the hydrolyzed cellulose, are
fermented to ethanol. Ethanol and lignin are mixed in a ratio of 3.8 parts of ethanol to
1.0 part lignin (weight/weight) to produce a petroleum-like fuel.
Development Status–A pilot plant testing the process employed by CBE was
reportedly operated for 24 months beginning in the mid-1990s. CBE has acquired a 20
acre site in Colusa, California to employ this process for the production of bioethanol,
silica/sodium oxide and lignin from waste rice straw and rice hulls. The company has
engaged an engineering firm to develop full plant specifications and plans. The
company began rice straw harvesting operations during the 2006 harvest season.
Future Development Plans–The Colusa Biomass Project is scheduled to be
initiated in the fourth quarter of 2007. The Colusa facility is planned to consume as
much as 165,000 tons of waste biomass annually, with planned production of from 10
to 20 million gallons of ethanol and 28,000 tons of silica/sodium oxide per year.
Silica/sodium oxide is a widely used ingredient with applications in the paper industry,
by detergent and soap producers and for the production of gels, catalysts and
zeolytes. CBE has also identified at least five additional locations in the U.S. for
possible future projects employing its technology.
DuPont and Co./POET, Wilmington, Delaware/Sioux Falls,
South Dakota
Organizational Background–DuPont and POET (formerly Broin Companies)
formed a partnership in 2006 to combine forces in developing and commercializing
technology for the production of ethanol from cellulosic biomass feedstocks, primarily
corn stover. DuPont, formed in 1802, is a large producer of chemicals and other
products, with operations in over 70 countries. Broin/POET, which began by building a
small-scale ethanol plant on the family’s Minnesota farm in 1983, has since designed
and constructed ethanol plants in five states, approaching a total of more than 30
plants. Since 2003, DuPont has been conducting a U.S. DOE-sponsored research
program to develop technology to produce ethanol from corn stover. In February 2007,
Broin/POET was awarded a U.S. DOE grant of up to $80 million to integrate cellulosic
ethanol production into an existing corn-to-ethanol facility at Emmetsburg, Iowa.
(Note: Separately, DuPont, in collaboration with BP, is pursuing development in the
UK of a process for producing butanol using sugar beets as feedstock. This process
development is not a subject of this study, since it does not thus far involve cellulosic
biomass feedstocks.)
Technology Characteristics–DuPont’s biomass-to-ethanol technology, shown in
Figure A19, is a mild alkaline enzymatic hydrolysis process developed in partnership
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