Process for the treatment of lignocellulosic biomass

• US 8,771,425 B2
• Filed: 08/21/2012
• Issued: 07/08/2014
• Est. Priority Date: 05/01/2006
• Status: Active Grant

• Current Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Original Assignee: The Board of Trustees of Michigan State University (Michigan State University)
• Inventors: Dale, Bruce E.
• Primary Examiner(s): Mi, Qiuwen
• Application Number:
  US13/591,092
• Publication Number:
  US 20120325202A1
• Time in Patent Office: 686 Days
• Field of Search: None
• US Class Current: 127/34
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 2201/00 Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C13K 1/02 obtained by saccharification of cellulosic materials manufacture of fodder A23K10/32
• CPC Class Codes: C13K 13/002 Xylose
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A process for the treatment of biomass to render structural carbohydrates more accessible and/or digestible using concentrated ammonium hydroxide with or without anhydrous ammonia addition, is described. The process preferably uses steam to strip ammonia from the biomass for recycling. The process yields of monosaccharides from the structural carbohydrates are good, particularly as measured by the enzymatic hydrolysis of the structural carbohydrates. The monosaccharides are used as animal feeds and energy sources for ethanol production.

Claims

1. A process for treating lignocellulosic biomass containing structural carbohydrates comprising:

adding ammonia vapors and water vapors at an elevated temperature to a closed vessel containing dry lignocellulosic biomass such that structural carbohydrates in the dry lignocellulosic biomass are rendered more susceptible to hydrolysis, wherein the ammonia vapors and the water vapors are added at an elevated pressure.

2. The process of claim 1 wherein a final mixture temperature in the closed vessel is 50°

C. or above.

3. The process of claim 2 wherein the final mixing temperature is about 90°

C.

4. The process of claim 1 wherein a ratio of ammonia in the ammonia vapors to the dry lignocellulosic biomass is from about 0.2:

1 to about 1;

1.

5. The process of claim 4 wherein a weight ratio of water in the water vapors to the dry lignocellulosic biomass is from about 0.4:

1 and to about 1;

1.

6. The process of claim 1 wherein the elevated pressure is released.

7. The process of claim 1 wherein a weight ratio of water in the water vapors to the dry lignocellulosic biomass is between about 0.4:

1 and about 1;

1.

8. The process of claim 1 wherein the elevated temperature is a temperature of a mixture of ammonia, biomass and water.

9. The process of claim 8 wherein the elevated temperature is between about 50°

C. and 120°

C.

10. The process of claim 9 wherein the elevated pressure is between about 4 and about 50 atm.

11. The process of claim 10 wherein the elevated pressure is between about 6.9 and 20.7 atm.

12. The process of claim 1 wherein the dry lignocellulosic biomass is ground dry lignocellulosic biomass.

13. The process of claim 1 further comprising obtaining monosaccharides from the treated dry lignocellulosic biomass.

14. The process of claim 13 wherein the monosaccharides are obtained by enzymatic hydrolysis, microbial conversion and/or animal digestion.

15. The process of claim 13 wherein the monosaccharides are recovered as a mixture of glucose, xylose, arabinose and other sugars.

16. The process of claim 14 wherein the enzymatic hydrolysis is performed with a cellulase enzyme.

17. The process of claim 14 wherein the microbial conversion produces organic acids, alcohols, and other byproducts.

18. The process of claim 14 wherein the animal digestion occurs in either ruminant or non-ruminant animal diets.

19. The process of claim 1 wherein the pressure is released rapidly.

20. A process comprising:

adding ammonia vapors and water vapors at an elevated temperature to a closed vessel containing dry plant biomass to produce pretreated dry plant biomass, wherein structural carbohydrates present in the dry plant biomass are rendered more susceptible to hydrolysis, and a weight ratio of water in the water vapors to the dry plant biomass is between about 0.4;

1 and about 1;

1.

21. The process of claim 20 wherein the method further comprises adding the ammonia vapors and the water vapors at an elevated pressure.

22. The process of claim 21 wherein the elevated pressure is between about 4 and about 50 atm.

23. The process of claim 21 wherein the elevated pressure is released.

24. The process of claim 20 wherein a ratio of ammonia in the ammonia vapors to the dry plant biomass is from about 0.2:

1 to about 1;

1.

25. The process of claim 20 wherein the dry plant biomass is corn stover or switchgrass.