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Biomass
contains cellulose wrapped in a recalcitrant lignin and hemicellulose
sheath that must be chemically and/or physically disrupted in a pretreatment
step. One of the most common
pretreatments involves exposure of the biomass to dilute acid at elevated
temperatures. Usually, sulfuric acid
is employed (rather than nitric or hydrochloric acid) because of its low
cost. However, pretreatment
expenditures are large, even when sulfuric acid is used, because substantial
quantities of acid are required, neutralization and disposal costs are
significant, and containment costs are high. It
has been discovered that biomass contains a significant mineral content, and
that these minerals neutralize some of the pretreatment acid, which increases
acid demand. Specific to sulfuric acid
is an equilibrium shift where formation of bisulfates
(HSO4), in addition to sulfates (SO42),
reduces hydrogen ion concentration and compounds the effect of
neutralization. This equilibrium shift
has a more pronounced effect at lower acid concentrations, where the amount
of hydrogen ion consumed represents a large percentage of the total hydrogen
ion concentration. Further, bisulfate
salt formation is favored when the acidic solutions are subjected to the high
temperatures used for pretreatment reactions.
Due to bisulfate salt formation, which is exacerbated at high
temperatures, the concentration of acid required to achieve a particular
reaction rate is increased. This
technology is claimed in the published United States Patent Application No
11/293,639. We are seeking an
industrial partner interested in its commercialization. (Ref: J282) |
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«Technology Transfer Office : Sponsored Projects : Dartmouth College |
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Phone: (603) 646-3027 |
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Fax: (603) 646-3670 |
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