METHODS FOR PRETREATING BIOMASS

• US 20140038243A1
• Filed: 12/22/2011
• Published: 02/06/2014
• 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: Balan, Venkatesh, Dale, Bruce E., Chundawat, Shishir, Sousa, Leonardo
• Granted Patent: US 9,644,222 B2
• Time in Patent Office: Days
• US Class Current: 435/99
• 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: 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 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: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02P 30/20 using bio-feedstock

Abstract

A method for treating biomass is provided, which includes, in a reactor, allowing gaseous ammonia to condense on the biomass and react with water present in the biomass to produce pretreated biomass, wherein reactivity of polysaccharides in the biomass is increased during subsequent biological conversion as compared to polysaccharides in biomass which has not been pretreated. A method for treating biomass with a liquid ammonia and recovering the liquid ammonia is also provided. Related systems which include a biochemical or biofuel production facility are disclosed.

Claims

1. A method for treating biomass comprising:

in a reactor, allowing gaseous ammonia to condense on the biomass and react with water present in the biomass to produce pretreated biomass, wherein reactivity of polysaccharides in the biomass is increased during subsequent biological conversion as compared to polysaccharides in biomass which has not been pretreated.

2. The method of claim 1 wherein the subsequent biological conversion comprises enzyme hydrolysis or ruminant digestibility;

and the method further comprises;

delivering the gaseous ammonia to the reactor; and

optionally adding water to the biomass.

3. The method of claim 1 wherein the polysaccharides include hemicellulose and cellulose and the reactivity is at least about 60% conversion of the hemicellulose and about 70% of cellulose to fermentable sugars within 24 hrs or less.

4. The method of claim 1 wherein the temperature in the reactor increases substantially instantaneously when the water and gaseous ammonia react and more than about 29.5% up to about 80% of glucan and xylan is converted to glucose within three days or less.

5. The method of claim 4 wherein the reactor temperature is between about 25°

C. and about 200°

C.

6. The method of claim 1 wherein the reactor temperature is between about 100°

C. and about 140°

C.

7. The method of claim 1 wherein the gaseous ammonia is delivered to the reactor at a pressure between about 6.8 atm and about 68 atm.

8. The method of claim 7 wherein the gaseous ammonia is delivered to the reactor at a pressure between about 6.8 atm and about 20.4 atm.

9. The method of claim 1 wherein the biomass is comprised of from about 5% to about 233% water on a dry weight basis.

10. The method of claim 1 wherein the biomass is comprised of from about 5% to about 100% water on a dry weight basis.

11. The method of claim 1 wherein the gaseous ammonia reacts with the water in the biomass for about 1 minute to about 36 hours.

12. The method of claim 10 wherein the gaseous ammonia reacts with the water in the biomass for about 1 minute to about 120 minutes.

13. The method of claim 1 wherein the biomass is substantially uniformly pretreated by the gaseous ammonia.

14. The method of claim 1 wherein the method is a continuous method.

15. The method of claim 1 further comprising delivering a carrier gas to the reactor.

16. The method of claim 15 wherein the carrier gas is combined with the gaseous ammonia.

17. The method of claim 16 wherein the carrier gas and the gaseous ammonia are combined before the gaseous ammonia is delivered to the reactor.

18. The method of claim 16 wherein the carrier gas and the gaseous ammonia are combined after the gaseous ammonia is delivered to the reactor.

19. The method of claim 16 wherein the carrier gas is oxidative.

20. The method of claim 19 wherein the carrier gas is air.

21. The method of claim 16 wherein the carrier gas is an inert gas.

22. The method of claim 21 wherein the inert gas is nitrogen.

23. The method of claim 15 wherein the carrier gas is steam.

24. The method of claim 1 wherein the reactor is a fluidized bed reactor.

25. The method of claim 1 wherein the reactor is a fixed bed reactor or a semi-fluidized bed reactor.

26. The method of claim 24 further comprising recycling at least a portion of the gaseous ammonia.

27. The method of claim 24 wherein the method is a semi-continuous batch method.

28. A method for treating biomass comprising:

in a reactor, impregnating biomass with an amount of ammonia to initiate a reaction, wherein the biomass contains water; and

allowing a gaseous carrier delivered to the reactor at an elevated temperature to remove residual ammonia in the biomass to produce pretreated biomass substantially free from ammonia, wherein the amount of ammonia is reduced as compared to reacting the ammonia and water without the gaseous carrier.

29. The method of claim 28 further comprising removing the pretreated biomass from the reactor.

30. A method for treating biomass comprising:

delivering ammonia at an elevated temperature to a reactor; and

allowing the gaseous ammonia to contact the biomass and react with water present in the biomass to produce pretreated biomass, wherein reactivity of polysaccharides in the biomass is increased during subsequent biological conversion as compared to polysaccharides in biomass which has not been pretreated.

31. The method of claim 30 wherein the ammonia is gaseous ammonia which condenses on the biomass.

32. The method of claim 30 wherein the ammonia is liquid ammonia and the ammonia vapor is recovered by:

cooling ammonia vapor produced after pretreated biomass containing the ammonia is subjected to high pressure steam in an ammonia column;

providing the ammonia vapor to a mixer;

adding water to the mixer to produce an ammonia-water mixture;

condensing the ammonia-water mixture to produce a condensed, ammonia-water mixture;

pressurizing the condensed ammonia-water mixture to produce a pressurized, condensed ammonia-water mixture; and

heating the pressurized, condensed ammonia-water mixture to produce a heated ammonia-water mixture.

33. The method of claim 32 further comprising providing the heated ammonia-water mixture to the reactor.

34. A system comprising:

a biofuel or biochemical production facility; and

a reactor at an elevated temperature containing biomass and ammonia, the biomass containing polysaccharides, wherein the reactor is adapted to allow the ammonia to contact the biomass and react with water present in the biomass to increase reactivity of the polysaccharides during subsequent biological conversion as compared to polysaccharides in biomass which has not been pretreated.

35. The system of claim 34 wherein the ammonia is gaseous ammonia which condenses on the biomass and the system further comprises an ammonia recovery system.

36. The system of claim 34 wherein the ammonia is liquid ammonia and the system further comprises an ammonia recovery system which comprises:

a first condenser adapted to cool ammonia vapor produced after pretreated biomass containing the ammonia is subjected to high pressure steam in an ammonia column;

a mixer adapted to mix the ammonia vapor and added water to produce an ammonia-water mixture;

one or more additional condensers for condensing the ammonia-water mixture;

one or more pumps to pressurize the ammonia-water mixture to produce a condensed, pressurized ammonia-water mixture; and

a heater for heating the condensed, pressurized ammonia-water mixture to produce a heated ammonia-water mixture.