Method and apparatus for conversion of cellulosic material to ethanol

• US 8,460,473 B2
• Filed: 01/31/2012
• Issued: 06/11/2013
• Est. Priority Date: 07/19/2005
• Status: Active Grant

• Current Assignee: Inbicon A/S
• Original Assignee: Inbicon A/S
• Inventors: Christensen, Borge Holm, Gerlach, Lena Holm
• Primary Examiner(s): DRODGE, JOSEPH W
• Application Number:
  US13/361,981
• Publication Number:
  US 20120138246A1
• Time in Patent Office: 497 Days
• Field of Search: 435132-136, 435161-165, 443/07, 444/50, 445/89, 445/90, 446/05, 446/06, 446/20, 210/632, 210/634, 210/760, 210/766, 210/806, 210/808, 210/770, 210/774, 127 34- 37, 127/42, 127/43, 127/65, 127/46.1, 127/53, 127/55, 426/618, 426/635, 426/636, 162/9, 162/18, 162/19, 162/24, 100/38, 422/600, 422/608, 422/616, 422/618, 422/630, 422/638, 422/642, 422/646, 422/649
• US Class Current: 127/37
• CPC Class Codes: B01J 19/245 placed in series
• CPC Class Codes: B01J 2219/00006 Large-scale industrial plants
• CPC Class Codes: C08B 1/003 Preparation of cellulose solutions, i.e. dopes, with different possible solvents, e.g. ionic liquids solutions used in the manufacture of monocomponent artificial filaments or cellulose or derivatives thereof D01F2/02
• CPC Class Codes: C08B 15/00 Preparation of other cellulose derivatives or modified cellulose , e.g. complexes
• CPC Class Codes: C08B 37/0057 beta-D-Xylans, i.e. xylosaccharide, e.g. arabinoxylan, arabinofuronan, pentosans; (beta-1,3)(beta-1,4)-D-Xylans, e.g. rhodymenans; Hemicellulose; Derivatives thereof
• CPC Class Codes: C08H 6/00 Macromolecular compounds derived from lignin, e.g. tannins, humic acids
• CPC Class Codes: C08H 8/00 Macromolecular compounds derived from lignocellulosic materials pretreatment thereof B27N
• CPC Class Codes: C12M 21/12 for producing fuels or solvents C12M21/04 takes precedence; liquid carbonaceous fuels C10L1/00, solid fuels C10L5/00
• CPC Class Codes: C12M 45/02 by mechanical forces; Stirring; Trituration; Comminuting crushing, pulverizing, disintegrating in general B02C
• CPC Class Codes: C12M 45/04 Phase separators; Separation of non fermentable material; Fractionation
• CPC Class Codes: C12M 45/09 by enzymatic treatment
• CPC Class Codes: C12M 45/20 Heating; Cooling heating or cooling apparatus for laboratory uses B01L7/00
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 19/14 produced by the action of a carbohydrase (EC 3.2.x), e.g. by alpha-amylase , e.g. by cellulase, hemicellulase
• CPC Class Codes: C12P 21/00 Preparation of peptides or proteins single cell protein C12N1/00
• CPC Class Codes: C12P 2201/00 Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• CPC Class Codes: C12P 2203/00 Fermentation products obtained from optionally pretreated or hydrolyzed cellulosic or lignocellulosic material as the carbon source ethanol C12P7/10
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C12P 7/14 Multiple stages of fermentation; Multiple types of microorganisms or re-use of microorganisms
• CPC Class Codes: C12P 7/56 Lactic acid
• CPC Class Codes: C13B 20/165 : using membranes, e.g. osmosis, ultrafiltration electrodialysis C13B20/18
• CPC Class Codes: C13K 1/02 : obtained by saccharification of cellulosic materials manufacture of fodder A23K10/32
• CPC Class Codes: D21C 9/18 : De-watering de-watering in general F26B; Elimination of cooking or pulp-treating liquors from the pulpD21C9/002, D21C9/02 take precedence; paper-making machines D21F; strainers in digesters D21C7/00; presses in general B30B
• CPC Class Codes: Y02E 50/10 : Biofuels, e.g. bio-diesel

Abstract

The present invention provides an apparatus and a method for conversion of cellulosic material, such as chopped straw and corn stover, and household waste, to ethanol and other products. The cellulosic material is subjected to continuous hydrothermal pre-treatment without addition of chemicals, and a liquid and a fiber fraction are produced. The fiber fraction is subjected to enzymatic liquefaction and saccharification. The method of the present invention comprises:

• • performing the hydrothermal pre-treatment by subjecting the cellulosic material to at least one soaking operation, and conveying the cellulosic material through at least one pressurized reactor, and subjecting the cellulosic material to at least one pressing operation, creating a fiber fraction and a liquid fraction;
  • selecting the temperature and residence time for the hydrothermal pretreatment, so that the fibrous structure of the feedstock is maintained and at least 80% of the lignin is maintained in the fiber fraction.

Claims

1. A method of continuous hydrothermal pretreatment of cellulosic material, preliminary to enzymatic liquefaction and saccharification, comprising the steps of:

conveying cellulosic feedstock through at least one continuous, pressurized reactor, having at least two consecutive sections, in such manner that the pressurized part of hydrothermal pretreatment is conducted at more than one set of temperature/pressure conditions with each set corresponding to a respective reactor section,

pressing the feedstock under pressurized conditions between each stage having a set of temperature/pressure conditions, thereby creating a fiber fraction and a liquid fraction, and

unloading the liquid fraction from the pressurized reactor between each stage having a set of temperature/pressure conditions.

2. The method of claim 1 wherein the feedstock is subjected to cutting, chopping, grinding or milling for particle size adjustment.

3. The method of claim 1 wherein each set of temperature/pressure conditions comprises temperatures between 170 and 230°

C.

4. The method of claim 1 wherein the feedstock is soaked at ambient pressures at temperatures up to 100°

C. prior to the pressurized hydrothermal pretreatment.

5. The method of claim 1 wherein liquid is removed from the feedstock by pressing during unloading of the at least one pressurized reactor using a sluice device.

6. The method of claim 1 wherein unloading of feedstock from the at least one pressurized reactor is accomplished using steam explosion.

7. The method of claim 1 wherein the pressing under pressurized conditions is accomplished by a pressing operation at the outlet of at least one pressurized reactor.

8. The method of claim 1 wherein the pressing under pressurized conditions is accomplished using a screw press.

9. The method of claim 1 wherein the feedstock is bagasse, corn stover or cereal straw.

10. The method of claim 1 wherein the feedstock is wheat straw.

11. The method of claim 1 wherein the temperature increases for each subsequent set of temperature/pressure conditions.

12. The method of claim 1 wherein there are two different sets of temperature/pressure conditions.

13. The method of claim 1 wherein each set of temperature/pressure conditions comprises temperatures between 100 and 230°

C.

14. The method of any one of claims 1 through 13 wherein solids unloaded from the at least one reactor are subsequently subject to enzymatic liquefaction and saccharification and further fermented to produce ethanol.

15. The method of any one of claims 1 through 13 wherein the liquid fraction is subsequently subject to fermentation to produce ethanol using a microorganism for conversion of C5 sugars to ethanol.