Process for Fractionating Lignocellulosic Biomass into Liquid and Solid Products
First Claim
1. A biomass fractionation process comprisinga) digesting a starting lignocellulosic-biomass material at a temperature of from about 120°
- C. to about 220°
C. and a pH of less than about 4, in an aqueous extractant mixture containing an effective concentration of a solvent for lignin, to form a digested mass that includes (1) one or more liquid phases that collectively contain dissolved lignin and, if hemicellulose is present in the starting lignocellulosic-biomass material, hemicellulose in dissolved or hydrolyzed form and (2) a solid phase containing cellulose; and
b) separating said liquid and solid phases to recover a solid phase that contains at least 75% of the cellulose originally in the starting lignocellulosic material and a liquid phase that contains at least 50% of the lignin originally in the starting lignocellulosic material and, if hemicellulose is present in the starting lignocellulosic-biomass material, at least 50% of the hemicellulose originally in the starting lignocellulosic material, in the form of hemicellulose sugars.
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Abstract
The invention herein is an efficient, flexible biomass fractionation process comprising digesting a lignocellulosic-biomass material at about 120-220° C. and a pH of less than about 4, in an aqueous mixture containing an effective concentration of at least one solvent for lignin, and separating to recover a solid phase that contains a large fraction of the cellulose originally in the starting lignocellulosic material and a liquid phase that contains most of the lignin and hemicellulose originally in the starting lignocellulosic biomass. The process can produce a solid phase that contains at least 75% cellulose and less than 10% lignin. The cellulose-rich solid product can be converted very efficiently to glucose. The solid product can also be used in commercial pulp applications, such as papermaking or fluff pulp. Hemicellulose sugars and lignin can be used directly or converted to other products.
99 Citations
30 Claims
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1. A biomass fractionation process comprising
a) digesting a starting lignocellulosic-biomass material at a temperature of from about 120° - C. to about 220°
C. and a pH of less than about 4, in an aqueous extractant mixture containing an effective concentration of a solvent for lignin, to form a digested mass that includes (1) one or more liquid phases that collectively contain dissolved lignin and, if hemicellulose is present in the starting lignocellulosic-biomass material, hemicellulose in dissolved or hydrolyzed form and (2) a solid phase containing cellulose; andb) separating said liquid and solid phases to recover a solid phase that contains at least 75% of the cellulose originally in the starting lignocellulosic material and a liquid phase that contains at least 50% of the lignin originally in the starting lignocellulosic material and, if hemicellulose is present in the starting lignocellulosic-biomass material, at least 50% of the hemicellulose originally in the starting lignocellulosic material, in the form of hemicellulose sugars. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
- C. to about 220°
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25. A cellulose-rich solid product having a liquid-absorption capacity of at least 13 g water per g dry solid.
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26. A cellulose-rich solid product which can be converted to glucose with at least 80% yield within 24 hours at 50°
- C. and 2 wt % solids, in the presence of a cellulase enzyme mixture in an amount of no more than 15 filter paper units (FPU) per g of the solid product.
- View Dependent Claims (27, 28)
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29. A biomass fractionation process comprising
a) digesting a starting lignocellulosic-biomass material at a temperature of from about 160° - C. to about 220°
C. and a pH of up to 3, in an aqueous extractant mixture containing an effective concentration of a solvent for lignin, to form a digested mass that includes (1) a liquid phases that collectively contains dissolved lignin and-hemicellulose in dissolved or hydrolyzed form and (2) a solid phase containing cellulose; andb) separating said liquid and solid phases to recover a solid phase that contains at least 90% of the cellulose originally in the starting lignocellulosic material and a liquid phase that contains at least 75% of the lignin originally in the starting lignocellulosic material and at least 75% of the hemicellulose originally in the starting lignocellulosic material, in the form of hemicellulose sugars; wherein the solvent for lignin includes at least one of methanol, ethanol, 1- and 2-propanol, glycerol, 1-butanol, 2-butanol, cyclohexanol, phenol, cresol, cyclohexanone, methyl ethyl ketone, and diethyl ether; wherein the extractant mixture contains at least one of sulfuric acid, sulfurous acid, hydrochloric acid, trifluoroacetic acid, lactic acid, ethyl lactate, citric acid, glycolic acid, and propionic acid; and wherein said separation is conducted at a temperature of at least about 120°
C. and under superatmospheric pressure such that the water and the solvent for lignin do not boil. - View Dependent Claims (30)
- C. to about 220°
Specification