Production of fermentable sugars and lignin from biomass using supercritical fluids

• US 8,968,479 B2
• Filed: 04/17/2013
• Issued: 03/03/2015
• Est. Priority Date: 01/19/2010
• Status: Active Grant

• Current Assignee: Renmatix, Inc.
• Original Assignee: Renmatix, Inc.
• Inventors: Kilambi, Srinivas, Kadam, Kiran L.
• Primary Examiner(s): Mayes, Melvin C
• Assistant Examiner(s): COHEN, STEFANIE J
• Application Number:
  US13/864,744
• Publication Number:
  US 20130239954A1
• Time in Patent Office: 685 Days
• Field of Search: None
• US Class Current: 127/44
• CPC Class Codes: B29C 48/41 Intermeshing counter-rotating screws
• CPC Class Codes: B29C 48/535 with thread pitch varying along the longitudinal axis
• 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 13/00 Sugars not otherwise provided for in this class
• CPC Class Codes: C13K 13/002 Xylose
• CPC Class Codes: D21C 1/00 Pretreatment of the finely-divided materials before digesting of waste paper D21C5/02
• CPC Class Codes: D21C 11/0007 Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042
• CPC Class Codes: D21C 3/22 Other features of pulping processes
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02P 20/54 using solvents, e.g. supercritical solvents or ionic liquids

Abstract

Methods are disclosed for the continuous treatment of biomass comprising a pretreatment step, wherein said biomass is contacted with a first supercritical, near-critical, or sub-critical fluid to form a solid matrix and a first liquid fraction; and a hydrolysis step, wherein said solid matrix formed in said pretreatment step is contacted with a second supercritical or near-supercritical fluid to produce a second liquid fraction and a insoluble lignin-containing fraction. Also disclosed are apparatuses for the continuous conversion of biomass comprising a pretreatment reactor and a hydrolysis reactor associated with said pretreatment reactor.

Claims

1. A method for the continuous treatment of biomass comprising:

a pretreatment step, wherein said biomass is contacted with a first supercritical, near-critical, or sub-critical fluid to form a solid matrix and a first liquid fraction;

wherein said first supercritical, near-critical, or sub-critical fluid comprises water and, optionally, CO2; and

wherein said first supercritical, near-critical, or sub-critical fluid is substantially free of C1-C5 alcohol;

a first separation step, wherein said solid matrix and said first liquid fraction are separated;

a hydrolysis step, wherein said solid matrix is contacted with a second supercritical or near-critical fluid to produce a second liquid fraction and an insoluble lignin-containing fraction;

wherein said second supercritical or near-critical fluid comprises water and, optionally, CO2; and

wherein said second supercritical or near-critical fluid is substantially free of C1-C5 alcohols.

2. The method of claim 1, wherein at least one of said first supercritical, near-critical, or sub-critical fluid and said second supercritical or near-critical fluid comprises less than about 10% carbon dioxide by weight based on the weight of said first supercritical, near-critical, or sub-critical fluid or said second supercritical or near-critical fluid.

3. The method of claim 1, wherein said pretreatment step occurs at a temperature and pressure below the critical point of at least one component of said first supercritical, near-critical, or sub-critical fluid.

4. The method of claim 1, wherein said pretreatment step is performed at a temperature of about 150°

C. to about 300°

C.

5. The method of claim 1, wherein said pretreatment step is performed at a pressure of about 50 bar to about 115 bar.

6. The method of claim 1, wherein said biomass has a residence time of about 1 minute to about 5 minutes in said pretreatment step.

7. The method of claim 1, wherein said first liquid fraction comprises xylo-oligosaccharides.

8. The method of claim 1, wherein said second supercritical or near-supercritical fluid does not include an acid.

9. The method of claim 1, wherein said solid matrix has a residence time of about 1 second to about 30 seconds in said hydrolysis step.

10. The method of claim 1, wherein said hydrolysis step occurs at a temperature and pressure above the critical point of at least one component of said second supercritical or near-critical fluid.

11. The method of claim 1, wherein said hydrolysis step occurs at a temperature from about 275°

C. to about 450°

C.

12. The method of claim 1, wherein said hydrolysis step occurs at a pressure of about 200 bar to about 250 bar.

13. The method of claim 1, wherein said solid matrix is kept at a temperature of about 185°

C. or higher from the beginning of said pretreatment step through at least the end of said hydrolysis step.

14. The method of claim 1, wherein at least one of said lignin fraction and said second liquid fraction is cooled to a temperature of about 180°

C. to about 240°

C.

15. The method of claim 14, further comprising flash cooling at least one of said lignin fraction and said second liquid fraction.

16. The method of claim 1, further comprising:

a second hydrolysis step wherein said second liquid fraction is contacted with a first hot compressed water, or a third near-critical or sub-critical fluid, to produce a third liquid fraction comprising glucose monomers;

wherein said third near-critical or sub-critical fluid comprises water; and

optionally, wherein said first hot compressed water or said third near-critical or sub-critical fluid comprises acid.

17. The method of claim 16, wherein said second hydrolysis step occurs at a temperature of about 220°

C. to about 320°

C.

18. The method of claim 16, wherein said second hydrolysis step occurs at a pressure of about 30 bar to about 90 bar.

19. The method of claim 16, wherein said acid is present in an amount less than about 1% by weight based on the weight of said first hot compressed water or said third near-critical or sub-critical fluid.

20. The method of claim 16, wherein said acid is present and is selected from the group consisting of hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfonic acid, phosphoric acid, phosphonic acid, nitric acid, nitrous acid, and combinations thereof.

21. The method of claim 16, wherein said second liquid fraction has a residence time of about 1 second to about 30 seconds in said second hydrolysis step.

22. The method of claim 16, wherein

said second hydrolysis step employs said first hot compressed water;

said first hot compressed water has a temperature of about 50°

C. to about 250°

C. and a pressure sufficient to maintain said first hot compressed water in a liquid state; and

said first hot compressed water comprises acid.

23. The method of claim 1, further comprising:

a xylo-oligosaccharide hydrolysis step, wherein said first liquid fraction is contacted with a second hot compressed water, or a fourth near-critical or sub-critical fluid, to produce a fourth liquid fraction comprising xylose monomers;

wherein said fourth near-critical or sub-critical fluid comprises water; and

optionally, wherein said second hot compressed water or said fourth near-critical or sub-critical fluid comprises acid.

24. The method of claim 23, wherein said acid is present and is selected from the group consisting of hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfonic acid, phosphoric acid, phosphonic acid, nitric acid, nitrous acid, and combinations thereof.

25. The method of claim 23, wherein said acid is present in an amount less than about 1% by weight based on the weight of said second hot compressed water or said fourth near-critical or sub-critical fluid.

26. The method of claim 23, wherein said xylo-oligosaccharide hydrolysis step occurs at a temperature of about 220°

C. to about 320°

C.

27. The method of claim 23, wherein said xylo-oligosaccharide hydrolysis step occurs at a pressure of about 30 bar to about 90 bar.

28. The method of claim 23, wherein said first liquid fraction has a residence time of about 1 second to about 30 seconds in said xylo-oligosaccharide hydrolysis step.

29. The method of claim 23, wherein

said xylo-oligosaccharide hydrolysis step employs said second hot compressed water;

said second hot compressed water has a temperature of about 50°

C. to about 250°

C. and a pressure sufficient to maintain said second hot compressed water in a liquid state; and

said second hot compressed water comprises acid.

30. A method of processing biomass comprising:

a pretreatment step, wherein said biomass is contacted with a first supercritical, near-critical, or sub-critical fluid to form a pretreated slurry comprising a solid matrix and a first liquid fraction comprising xylo-oligosaccharides;

wherein said first supercritical, near-critical, or sub-critical fluid comprises water and, optionally, CO₂; and

wherein said first supercritical, near-critical, or sub-critical fluid is substantially free of C₁-C₅ alcohol;

a first separation step, wherein said solid matrix and said first liquid fraction are separated;

a first hydrolysis step, wherein said solid matrix is contacted with a second supercritical or near-critical fluid to form an insoluble lignin-containing fraction and a second liquid fraction comprising cello-oligosaccharides;

wherein said second supercritical or near-critical fluid comprises water and, optionally, CO₂; and

wherein said second supercritical or near-critical fluid is substantially free of C₁-C₅ alcohol;

a second separation step, wherein said insoluble lignin-containing fraction and said second liquid fraction are separated; and

a second hydrolysis step, wherein said second liquid fraction is contacted with a third near-critical or sub-critical fluid to form a product comprising glucose monomers;

wherein said third near-critical or sub-critical fluid comprises water and, optionally, acid.

31. The method of claim 30, further comprising:

a third hydrolysis step, wherein said first liquid fraction is contacted with a fourth near-critical or sub-critical fluid to form a second product comprising xylose monomers;

wherein said fourth near-critical or sub-critical fluid comprises water and, optionally, acid.