US 4,612,286 A · Acid hydrolysis of biomass for alcohol production

Abstract

A method of treating biomass having fermentable material is provided utilizing acid hydrolysis in a countercurrent diffusion treatment structure. By practicing the invention acid usage is minimized, pentose concentration in the hydrolysate solution is maximized, and ethanol, butanol, butanediol, and the alcohols can be produced without the input of any external energy whatsoever into the production method. Biomass is particlized and slurried, and then is continuously subjected to acid hydrolysis at temperature, acid concentration, and residence time conditions sufficient to effect hydrolysis of the hemicellulose in the biomass to effect separation of pentose and hexose sugars into a hydrolysate having insufficient furfural to substantially inhibit fermentation microorganism growth, while not substantially hydrolyzing the cellulose in the biomass. Fermentation of the pentose and hexose sugars in the hydrolysate may then be effected, and alcohol produced from the fermented pentose and hexose sugars utilizing conventional techniques. Hydrolysis is practiced in an upright diffusion vessel with countercurrent flow, the acid concentration being about 2 to 10%, the temperature in the vessel being about 120.degree. C. or less, the residence time of the biomass in the vessel being about 1 to 3 hours, the biomass solids to liquid ratio being about 20/100 to 40/100 on a volume basis, and the particle size of the biomass being about 1-4 mm.

Claims20

Dependent claims

A method of producing fuel alcohol from biomass containing carbohydrate and lignin, comprising the steps of:

(a) particlizing and slurrying the biomass;
(b) continuously subjecting the biomass to acid hydrolysis at temperature, acid concentration, and residence time conditions sufficient to effect hydrolysis of the hemicellulose in the biomass to effect separation of pentose and hexose sugars therefrom into a hydrolysate having insufficient furfural to substantially inhibit fermentation microorganisms growth, while not substantially hydrolyzing the cellulose in said biomass by:
establishing a flow of the slurried biomass in a first direction in a vessel;
contacting the flowing slurry with a plurality of concentric non-rotatable screen members each having an apertured face and having a conduit leading away from the face to an area remote from said flow;
introducing dilute acid into the slurry flow through a plurality of rotatable spray tubes extending parallel to the direction of said slurry and disposed between said screen members in a direction perpendicular to the direction of flow;
removing hydrolysate from the flow by withdrawing liquid through the screen members and passing it through the conduit;
and moving the screen members alternately generally in said direction of slurry flow and in a direction opposite said direction of slurry flow;
(c) effecting fermentation of the pentose and hexose sugars in said hydrolysate;
and
(d) producing fuel alcohol from the fermented pentose and hexose sugars.

7 more elements

A method of effecting acid hydrolysis of biomass utilizing an upright vessel having a plurality of sets of apparatus, each apparatus set including a plurality of concentric non-rotatable screen members each having an apertured face and having a conduit leading away from the face to an area remote from the screen members, and a plurality of vertically extending rotatable spray tubes disposed between the screen members, and means for moving the screen members alternately upwardly and downwardly, the apparatus sets being vertically spaced in the vessel and the conduits extending from the screen members in an apparatus set being operatively connected to the spray tubes in the next lower apparatus set, and the conduits in the lowermost apparatus set leading exteriorly of the vessel to a further remote treatment point;

said method comprising the steps of continuously:
particlizing and slurrying the biomass;
flowing the slurry upwardly in the vessel past the apparatus sets;
moving the screen members of each set upwardly and downwardly;
introducing hot washing liquid into the spray tubes of the uppermost apparatus set;
passing withdrawn liquid from each apparatus set screen members to the next lowermost apparatus set spray tubes;
introducing acid into the withdrawn liquid between one of the apparatus set screen members and the next lowermost set spray tubes;
withdrawing as hydrolysate the liquid withdrawn from the lowermost apparatus set screen members, and passing it on to a further remote treatment point;
and
withdrawing the biomass slurry from the top of the vessel and dewatering it.

7 more elements

Dependencies are inferred from the claim text.

Acid hydrolysis of biomass for alcohol production

Life of this patent

Acid hydrolysis of biomass for alcohol production

Life of this patent

Abstract

Claims20