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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 issued United States Patent No 7,503,981, and
the published United States Patent Application No. 12/366,360. 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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