Sulfur dioxide and/or sulfurous acid pretreatment
First Claim
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1. A method for pretreating and hydrolyzing lignocellulosic biomass comprising:
- a) adding acid to the lignocellulosic biomass to produce acidified lignocellulosic biomass, said acid comprising at least one of sulfur dioxide and sulfurous acid;
b) pretreating the acidified lignocellulosic biomass in at least one pretreatment reactor to provide a pretreated slurry having a pH less than 1.5, said pretreated slurry comprising cellulose, said acidified lignocellulosic biomass having a consistency between 14.5 wt % and 51 wt %, said at least one pretreatment reactor comprising a first pretreatment reactor, said pretreating conducted at a temperature greater than 170°
C. and under pretreating conditions wherein a product of sulfur dioxide dosage and Vs/Vr is greater than 0.8 wt %, where Vs/Vr is a ratio of slurry volume to reactor volume and where sulfur dioxide dosage is a ratio of grams of sulfur dioxide present in the first pretreatment reactor to grams of dry lignocellulosic biomass present in the first pretreatment reactor expressed as a weight percentage; and
c) hydrolyzing the cellulose from the pretreated slurry with an enzyme to produce glucose.
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Abstract
A process for producing alcohol from lignocellulosic biomass includes adding at least one of sulfur dioxide and sulfurous acid to the lignocellulosic biomass to provide an effective sulfur dioxide dosage and/or effective sulfur dioxide slurry concentration, each of which is calculated using the ratio of the volume of the slurry in the pretreatment reactor to the total volume of the pretreatment reactor, within a predetermined range.
47 Citations
23 Claims
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1. A method for pretreating and hydrolyzing lignocellulosic biomass comprising:
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a) adding acid to the lignocellulosic biomass to produce acidified lignocellulosic biomass, said acid comprising at least one of sulfur dioxide and sulfurous acid; b) pretreating the acidified lignocellulosic biomass in at least one pretreatment reactor to provide a pretreated slurry having a pH less than 1.5, said pretreated slurry comprising cellulose, said acidified lignocellulosic biomass having a consistency between 14.5 wt % and 51 wt %, said at least one pretreatment reactor comprising a first pretreatment reactor, said pretreating conducted at a temperature greater than 170°
C. and under pretreating conditions wherein a product of sulfur dioxide dosage and Vs/Vr is greater than 0.8 wt %, where Vs/Vr is a ratio of slurry volume to reactor volume and where sulfur dioxide dosage is a ratio of grams of sulfur dioxide present in the first pretreatment reactor to grams of dry lignocellulosic biomass present in the first pretreatment reactor expressed as a weight percentage; andc) hydrolyzing the cellulose from the pretreated slurry with an enzyme to produce glucose. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for pretreating and hydrolyzing lignocellulosic biomass comprising:
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a) adding acid to the lignocellulosic biomass to produce acidified lignocellulosic biomass, said acid comprising at least one of sulfur dioxide and sulfurous acid; b) pretreating the acidified lignocellulosic biomass in at least one pretreatment reactor to provide a pretreated slurry, said pretreated slurry comprising cellulose and having a pH that is less than 1.55, said acidified lignocellulosic biomass having a consistency that is greater than 14.5 wt % and less than 50.5 wt %, said at least one pretreatment reactor comprising a first pretreatment reactor having a reactor volume Vr and a slurry volume Vs; and c) hydrolyzing the cellulose with an enzyme to produce glucose, wherein adding the acid to the lignocellulosic biomass comprises adding an amount of the acid that provides an effective sulfur dioxide dosage that is greater than 1 wt % and an effective sulfur dioxide slurry concentration that is between 0.25 wt % and 1.5 wt %, said effective sulfur dioxide slurry concentration calculated from the product of the sulfur dioxide slurry concentration in the first pretreatment reactor and Vs/Vr, said sulfur dioxide slurry concentration calculated from the ratio of grams of sulfur dioxide present to grams of moisture present expressed as a weight percentage, said effective sulfur dioxide dosage calculated from the product of sulfur dioxide dosage in the first pretreatment reactor and Vs/Vr, and wherein said pretreating is conducted at a temperature greater than 170°
C. - View Dependent Claims (21, 22)
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23. A method for pretreating and hydrolyzing lignocellulosic biomass comprising:
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a) adding acid to the lignocellulosic biomass to produce acidified lignocellulosic biomass, said acid comprising at least one of sulfur dioxide and sulfurous acid; b) pretreating the acidified lignocellulosic biomass in at least one pretreatment reactor to provide a pretreated slurry having a pH less than 1.5, said pretreated slurry comprising cellulose, said acidified lignocellulosic biomass having a consistency between 14.5 wt % and 40.5 wt %, said at least one pretreatment reactor comprising a first pretreatment reactor, said pretreating conducted at a temperature greater than 170°
C. and under pretreating conditions wherein a product of sulfur dioxide loading and Vs/Vr is greater than 0.8 wt %, where Vs/Vr is a ratio of slurry volume to reactor volume and where sulfur dioxide loading is a ratio of grams of sulfur dioxide fed to the first pretreatment reactor to grams of dry lignocellulosic biomass fed to the first pretreatment reactor expressed as a weight percentage; andc) hydrolyzing the cellulose from the pretreated slurry with an enzyme to produce glucose, wherein said acid is added to the lignocellulosic biomass in an amount sufficient to provide a sulfur dioxide loading of at least 20 wt %.
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Specification