Methods and systems for biomass conversion to carboxylic acids and alcohols

• US 20060024801A1
• Filed: 06/16/2005
• Published: 02/02/2006
• Est. Priority Date: 06/16/2004
• Status: Active Grant

• Current Assignee: Texas A&M University System
• Original Assignee: Texas A&M University System
• Inventors: Holtzapple, Mark Thomas, Davison, Richard
• Granted Patent: US 7,820,417 B2
• Time in Patent Office: Days
• US Class Current: 435/136
• CPC Class Codes: C07C 29/149 with hydrogen or hydrogen-containing gases
• CPC Class Codes: C07C 31/125 containing five to twenty-two carbon atoms
• 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 21/16 Solid state fermenters, e.g. for koji production
• CPC Class Codes: C12M 29/02 Percolation
• CPC Class Codes: C12M 43/02 Bioreactors or fermenters combined with devices for liquid fuel extraction; Biorefineries
• CPC Class Codes: C12M 45/06 by chemical means or hydrolysis
• CPC Class Codes: C12M 47/00 Means for after-treatment of the produced biomass or of the fermentation or metabolic products, e.g. storage of biomass filters in general B01D24/00 - B01D41/00
• CPC Class Codes: C12P 7/02 containing a hydroxy group
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C12P 7/40 containing a carboxyl group including Peroxycarboxylic acids
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

The disclosure includes a method, process and apparatus for the conversion of biomass to carboxylic acids and/or primary alcohols. The system may include a pretreatment/fermentation subsystem operable to produce a fermentation broth containing carboxylic acid salts from biomass, such as lignocellulosic biomass. The system may also include a dewatering subsystem operable to remove excess water from the fermentation broth to produce a concentrated product. The system may also includes an acid springing subsystem operable to produce a mixed carboxylic acid product. The system may also include a hydrogenation subsystem operable to produce an alcohol mixture, such as a mixture containing primary alcohols. Methods of operating this system or other systems to obtain a carboxylic acid or alcohol mixture are also provided.

Claims

1. A system for the conversion of biomass comprising:

a pretreatment/fermentation subsystem operable to;

pretreat biomass with lime or quick lime and air to produce treated biomass; and

ferment the treated biomass with an inoculum to produce a fermentation broth containing carboxylic acid salts;

a dewatering subsystem operable to;

remove excess water from the fermentation broth to produce a concentrated product; and

an acid springing subsystem operable to;

combine the concentrated product with a low-molecular-weight tertiary amine or ammonia to produce a low-molecular-weight tertiary amine or ammonia carboxylate product from the carboxylic acid salts;

replace the low-molecular-weight tertiary amine or ammonia in the low-molecular-weight tertiary amine or ammonia carboxylate product with a high-molecular-weight tertiary amine to form a high-molecular-weight tertiary amine carboxylate product; and

thermally break the amine-carboxylate bonds in the high-molecular-weight tertiary amine carboxylate product to produce a mixed carboxylic acid product.

2. A system according to claim 1, further comprising a hydrogenation subsystem operable to:

combine the mixed carboxylic acid produce with a high-molecular-weight alcohol to form an ester;

convert the ester to an alcohol mixture using a hydrogenation catalyst; and

separate the alcohol mixture from the high-molecular-weight alcohol.

3. A system according to claim 1, where the biomass comprises lignocellulosic biomass.

4. A system according to claim 1, wherein the pretreatment/fermentation subsystem further comprises:

a pit having;

a liner;

gravel placed on the liner; and

a perforated drain pipe embedded in the gravel;

a biomass pile located on top of the pit;

a cover over the biomass pile; and

a pump operable to circulate water from the pit to the top of the biomass pile.

5. A system according to claim 4, wherein the pretreatment/fermentation subsystem further comprises:

a blower operable to circulate air through the biomass pile; and

a lime water slurry operable to remove carbon dioxide from the air.

6. A system according to claim 1, wherein the innoculum comprises a salt-tolerant microorganism.

7. A system according to claim 1, wherein the dewatering subsystem further comprises:

a high-molecular-weight carboxylic acid added to the fermentation broth to produce acidified fermentation broth; and

an evaporator operable to concentrate the acidified fermentation broth.

8. A system according to claim 7, wherein the high-molecular-weight carboxylic acid comprises caproic acid, valeic acid or hepotanoic acid.

9. A system according to claim 1, wherein the acid springing subsystem further comprises:

a mixer to operable to mix the concentrated product with the low-molecular-weight tertiary amine or ammonia and carbon dioxide;

a column operable to exchange the low-molecular-weight tertiary amine or ammonia in the low-molecular-weight tertiary amine or ammonia carboxylate product for a high-molecular-weight tertiary amine; and

a column operable to thermally break the amine-carboxylate bonds in the high-molecular-weight tertiary amine carboxylate product to produce a mixed carboxylic acid product.

10. A system according to claim 1, wherein the low-molecular-weight tertiary amine comprises triethyl amine.

11. A system according to claim 1, wherein the high-molecular-weight tertiary amine comprises trioctyl amine or triethanol amine.

12. A system according to claim 2, wherein the hydrogenation subsystem further comprises:

a column operable to combine the mixed carboxylic acid produce with a high-molecular-weight alcohol to form an ester;

a hydrogenation reactor operable to convert the ester to an alcohol mixture using a hydrogenation catalyst; and

a column operable to separate the alcohol mixture from the high-molecular-weight alcohol.

13. A system according to claim 2, wherein the high-molecular-weight alcohol comprises heptanol.

14. A system according to claim 2, wherein the alcohol mixture substantially comprises primary alcohols.

15. A system according to claim 1, further comprising the system operable to recycle process heat within at least one subsystem or from one subsystem to another.

16. A system according to claim 1, further comprising the system operable to recycle water within at least one subsystem or from one subsystem to another.

17. A system according to claim 1, further comprising the system operable to recycle lime or quick lime within at least one subsystem or from one subsystem to another.

18. A system for the conversion of biomass comprising:

a pretreatment/fermentation means operable to;

pretreat biomass with lime or quick lime and air to produce treated biomass; and

ferment the treated biomass with an inoculum to produce a fermentation broth containing carboxylic acid salts;

a dewatering means operable to;

remove excess water from the fermentation broth to produce a concentrated product; and

an acid springing means operable to;

combine the concentrated product with a low-molecular-weight tertiary amine or ammonia to produce a low-molecular-weight tertiary amine or ammonia carboxylate product from the carboxylic acid salts;

replace the low-molecular-weight tertiary amine or ammonia in the low-molecular-weight tertiary amine or ammonia carboxylate product with a high-molecular-weight tertiary amine to form a high-molecular-weight tertiary amine carboxylate product; and

thermally break the amine-carboxylate bonds in the high-molecular-weight tertiary amine carboxylate product to produce a mixed carboxylic acid product.

19. A system according to claim 18, further comprising a hydrogenation means operable to:

combine the mixed carboxylic acid produce with a high-molecular-weight alcohol to form an ester;

convert the ester to an alcohol mixture using a hydrogenation catalyst; and

separate the alcohol mixture from the high-molecular-weight alcohol.

20. A method of obtaining a fermentation product comprising:

treating a pile of biomass with lime or quick lime, water, an innoculum and air to produce a fermentation broth;

acidifying the fermentation broth with a high-molecular-weight carboxyllic acid to produce acidified fermentation broth;

stripping the fermentation broth in a stripping column to produce stripped fermentation broth;

concentrating the stripped fermentation broth in an evaporator to produce concentrated product;

mixing the concentrated product with a low-molecular-weight tertiary amine or ammonia and carbon dioxide to produce a low-molecular-weight tertiary amine or ammonia carboxylate;

exchanging the low-molecular-weight tertiary amine or ammonia carboxylate with a high-molecular-weight tertiary amine to produce a high-molecular-weight tertiary amine carboxylate;

heating the high-molecular-weight tertiary amine carboxylate to a temperature sufficient to break acid/amine bonds to produce a free carboxylic acid product; and

recovering the free carboxylic acid product.

21. A method according to claim 20 further comprising:

combining the carboxylic acid produce with a high-molecular-weight alcohol to from an ester;

hydrogenating the ester to form an alcohol product;

separating the high-molecular-weight alcohol from the alcohol product; and

recovering the alcohol product.

22. A method according to claim 20, wherein the biomass comprises lignocellulosic biomass.

23. A method according to claim 22, wherein the alcohol produce substantially comprises primary alcohols.