FRACTIONATION OF LIGNOCELLULOSIC BIOMASS FOR CELLULOSIC ETHANOL AND CHEMICAL PRODUCTION
First Claim
1. A continuous process for fractionation of lignocellulosic biomass having a lignin content of less than 12% and an acetyl group content of 3-6% weight/weight in the dry matter, comprising the steps of:
- a) autohydrolysis of the hemicellulose fraction in the lignocellulosic biomass in the absence of any added acid catalyst, by exposing the biomass in a reaction vessel to steam at an elevated temperature and reaction pressure and for a preselected exposure time to achieve a severity index of about 4.0, the severity index (SI) being calculated as
SI=Log×
Exp [(treatment temperature (°
C.)−
100°
C.)/14.75]×
Retention Time (min),to obtain a prehydrolyzed lignocellulosic biomass;
b) purging liquid condensate and vapor generated during the exposing step to remove and collect a first liquid stream with water soluble compounds and a first vapor stream with volatile chemicals;
c) liquid extracting from the prehydrolyzed lignocellulosic biomass a liquid hemicellulose degradation stream containing hemicellulose hydrolysis and degradation components;
d) rapidly releasing the reaction pressure after the extracting step to afford explosive decompression of the extracted, prehydrolyzed lignocellulosic biomass into fibrous solids, vapor and condensate;
e) collecting vapor and condensate released during the explosive decompression as a second vapor stream and a second liquid stream; and
f) combining the first and second liquid streams with the liquid hemicellulose degradation stream for separation and recovery of byproducts.
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Accused Products
Abstract
A process is defined for the continuous steam pretreatment and fractionation of corn cobs and low lignin lignocellulosic biomass to produce a concentrated cellulose solid stream that is sensitive to enzymatic hydrolysis. Valuable chemicals are recovered by fractionating the liquid and vapor stream composed of hydrolysis and degradation products of the hemicellulose. Cellulosic derived glucose is produced for fermentation to biofuels. A hemicellulose concentrate is recovered that can be converted to value added products including ethanol.
10 Citations
10 Claims
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1. A continuous process for fractionation of lignocellulosic biomass having a lignin content of less than 12% and an acetyl group content of 3-6% weight/weight in the dry matter, comprising the steps of:
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a) autohydrolysis of the hemicellulose fraction in the lignocellulosic biomass in the absence of any added acid catalyst, by exposing the biomass in a reaction vessel to steam at an elevated temperature and reaction pressure and for a preselected exposure time to achieve a severity index of about 4.0, the severity index (SI) being calculated as
SI=Log×
Exp [(treatment temperature (°
C.)−
100°
C.)/14.75]×
Retention Time (min),to obtain a prehydrolyzed lignocellulosic biomass; b) purging liquid condensate and vapor generated during the exposing step to remove and collect a first liquid stream with water soluble compounds and a first vapor stream with volatile chemicals; c) liquid extracting from the prehydrolyzed lignocellulosic biomass a liquid hemicellulose degradation stream containing hemicellulose hydrolysis and degradation components; d) rapidly releasing the reaction pressure after the extracting step to afford explosive decompression of the extracted, prehydrolyzed lignocellulosic biomass into fibrous solids, vapor and condensate; e) collecting vapor and condensate released during the explosive decompression as a second vapor stream and a second liquid stream; and f) combining the first and second liquid streams with the liquid hemicellulose degradation stream for separation and recovery of byproducts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification