METHOD OF OBTAINING INORGANIC SALT AND ACETATE SALT FROM CELLULOSIC BIOMASS

• US 20080182305A1
• Filed: 01/24/2008
• Published: 07/31/2008
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: Iogen Energy Corporation (Iogen Corporation)
• Original Assignee: Iogen Energy Corporation (Iogen Corporation)
• Inventors: Tolan, Jeffrey S., Foody, Brian
• Granted Patent: US 8,247,200 B2
• Time in Patent Office: Days
• US Class Current: 435/140
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 7/54 Acetic acid vinegar C12J

Abstract

A process for obtaining inorganic salt and acetate salt from cellulosic biomass is disclosed. The cellulosic biomass is pretreated by adding one or more than one acid or base to produce a pretreated cellulosic biomass comprising acetic acid or acetate salt. One or more than one base or acid is then added to the pretreated cellulosic biomass to adjust the pretreated cellulosic biomass to a pH of about 4.0 to about 6.0 to produce a neutralized cellulosic biomass comprising inorganic salt and acetate salt. The neutralized biomass is then hydrolyzed by cellulase enzymes to produce a sugar stream. Streams arising from the processing of the cellulosic biomass to sugar are subjected to ion exclusion chromatography performed at pH 5.0 to about 10.0 to produce a stream comprising an inorganic salt and an acetate salt.

Claims

1. A process for producing a salt stream comprising inorganic salt and acetate salt by processing a cellulosic biomass, the process comprising:

a) pretreating the cellulosic biomass by adding a base to the cellulosic biomass to produce a pretreated cellulosic biomass comprising the acetate salt;

b) adding an acid to the pretreated cellulosic biomass to adjust the pretreated cellulosic biomass to a pH of about 4.0 to about 6.0, thereby producing a neutralized cellulosic biomass;

c) hydrolyzing the neutralized cellulosic biomass with cellulase enzymes to produce a crude sugar stream;

d) separating insoluble residue from the crude sugar stream to produce a clarified sugar stream; and

e) feeding an aqueous stream obtained from the pretreated cellulosic biomass, an aqueous stream obtained from the neutralized cellulosic biomass, the clarified sugar stream, or a combination thereof, to an ion exclusion chromatographic separation to produce the salt stream comprising inorganic salt and acetate salt, which ion exclusion separation is performed at a pH range between about 5.0 and about 10.0 using a cation exchange resin.

2. The process of claim 1 wherein, in the step of feeding (step e)), the ion exclusion chromatography is performed at a pH of between about 6 and about 10.

3. The process of claim 1, wherein the clarified sugar stream is fed to the ion exclusion chromatographic separation, and, wherein, said ion exclusion separation further produces a purified sugar stream.

4. The process of claim 1, wherein the aqueous stream obtained from the pretreated cellulosic biomass is produced after a step of washing the pretreated biomass, which aqueous stream is then subjected to an acid addition step.

5. The process of claim 1, wherein the aqueous stream obtained from the pretreated cellulosic biomass is produced after a step of removing insoluble solids from the pretreated biomass, which aqueous stream is then subjected to an acid addition step.

6. The process of claim 1, wherein the aqueous stream obtained from the neutralized cellulosic biomass is produced after a step of washing the neutralized biomass.

7. The process of claim 1, wherein the aqueous stream obtained from the neutralized cellulosic biomass is produced after a step of removing insoluble solids from the neutralized biomass.

8. The process of claim 3 wherein, after the chromatographic separation, the purified sugar stream is fermented.

9. The process of claim 8, wherein the sugar is fermented to produce ethanol, lactic acid or butanol.

10. The process of claim 1 further comprising a step of recovering the salt stream comprising inorganic salt and acetate salt.

11. The process of claim 1, wherein, during the step of feeding (step e)), the ion exclusion chromatography is carried out using a Simulated Moving Bed (SMB) system or an Improved Simulated Moving Bed (ISMB) system.

12. The process of claim 1, wherein the clarified sugar stream is characterized by having a lignosulfonate content of from about 0 to about 4% of the total solids present in the clarified sugar stream.

13. The process of claim 1, wherein the cellulosic biomass is obtained from a feedstock selected from the group consisting of an agricultural waste, corn stover, wheat straw, barley straw, canola straw, oat straw, rice straw, soybean stover, a grass, switch grass, miscanthus, cord grass, reed canary grass, a forestry residue, aspen wood or sawdust, a sugar residue, bagasse and beet pulp.

14. The process of claim 1, wherein the acid is sulfuric acid and the inorganic salt comprises a sulfate salt.

15. The process of claim 1, wherein the dosage of the cellulase enzymes is about 5 to about 50 IU per gram of cellulose.

16. The process of claim 1, further comprising adding at least one xylanase enzyme during said step of hydrolyzing.

17. The process of claim 1, wherein the inorganic salt is an ammonium salt.

18. The process of claim 1, wherein the cellulosic biomass is pressed or leached prior to the step of pretreating (step a)).

19. The process of claim 11, wherein the SMB system or ISMB system is operated with 4 to 16 shifts of feed and collection positions per cycle.

20. The process of claim 19, wherein the SMB system or ISMB system is operated with 4 to 12 shifts of feed and collection positions per cycle.

21. The process of claim 1, wherein the inorganic salt from the salt stream is recovered for use as a fertilizer.

22. The process of claim 1, wherein, in the step of pretreating (step a)), the base is a soluble base.

23. The process of claim 22, wherein the soluble base is selected from the group consisting of sodium hydroxide, potassium hydroxide, ammonia and ammonium hydroxide.

24. The process of claim 1, wherein, in the step of separating (step d)), the insoluble residue is separated from the crude sugar stream by microfiltration, plate and frame filtration, crossflow filtration, pressure filtration, vacuum filtration or centrifugation.

25. The process of claim 1, wherein insoluble residue is separated from the aqueous stream obtained from the pretreated cellulosic biomass or the aqueous stream obtained from the neutralized cellulosic biomass by microfiltration, plate and frame filtration, crossflow filtration, pressure filtration, vacuum filtration or centrifugation prior to the chromatographic separation.

26. The process of claim 2, wherein the ion exclusion chromatography is performed at a pH of between about 6.5 and about 10.

27. The process of claim 2, wherein the ion exclusion step is performed at a pH of between about 6 and about 8.

28. The process of claim 1, wherein the clarified sugar stream, the aqueous stream obtained from the pretreated cellulosic biomass or the aqueous stream obtained from the neutralized cellulosic biomass is concentrated prior to or during the chromatographic separation.

29. The process of claim 3, wherein the purified sugar stream is concentrated.

30. A process for producing a salt stream comprising an inorganic salt and acetate salt by processing a cellulosic biomass, the process comprising:

a) pretreating the cellulosic biomass by adding a base to the cellulosic biomass to produce a pretreated cellulosic biomass comprising the acetate salt;

b) adding an acid to the pretreated cellulosic biomass to adjust the pretreated cellulosic biomass to a pH of about 4.0 to about 6.0, thereby producing a neutralized cellulosic biomass;

c) hydrolyzing the neutralized cellulosic biomass with cellulase enzymes to produce a crude sugar stream;

d) fermenting the sugar stream to produce a fermentation broth comprising ethanol;

e) distilling the fermentation broth to produce concentrated ethanol and still bottoms; and

f) feeding the still bottoms to an ion exclusion chromatographic separation to produce the salt stream comprising inorganic salt and acetate salt, which ion exclusion separation is performed at a pH range between about 5.0 and about 10.0 using a cation exchange resin.

31. The process of obtaining inorganic and acetate salts according to claim 30, wherein said ion exclusion separation step (f) is performed on an aqueous stream obtained from said still bottoms.

32. A process for obtaining ethanol or butanol by processing a cellulosic biomass, the process comprising:

a) pretreating the cellulosic biomass by adding a base to the cellulosic biomass to produce a pretreated cellulosic biomass comprising acetate salt;

b) adding an acid to the pretreated cellulosic biomass to adjust the pretreated cellulosic biomass to a pH of about 4.0 to about 6.0, thereby producing a neutralized cellulosic biomass comprising inorganic salt;

c) hydrolyzing the neutralized cellulosic biomass with cellulase enzymes to produce a crude sugar stream;

d) separating insoluble residue from the crude sugar stream to produce a clarified sugar stream;

e) feeding the clarified sugar stream to an ion exclusion chromatographic separation to produce a salt stream comprising inorganic salt and acetate salt and a purified sugar stream, which ion exclusion separation is performed at a pH range between about 5.0 and about 10.0 using a cation exchange resin;

f) fermenting the purified sugar stream to produce ethanol or butanol in a fermentation broth; and

g) isolating the ethanol or butanol produced in step (f).

33. A process for producing a salt stream comprising inorganic salt and acetate salt by processing a cellulosic biomass, the process comprising:

a) pretreating the cellulosic biomass with a base to produce a pretreated cellulosic biomass comprising acetate salt;

b) obtaining an aqueous stream from the pretreated cellulosic biomass;

c) treating said aqueous stream with an acid to produce an acid-treated aqueous stream comprising inorganic salt; and

d) feeding the acid-treated aqueous stream to an ion exclusion chromatographic separation to produce the salt stream comprising the inorganic salt and the acetate salt, which ion exclusion separation is performed at a pH range between about 5.0 and about 10.0 using a cation exchange resin.