RECOVERY OF INORGANIC SALT DURING PROCESSING OF LIGNOCELLULOSIC FEEDSTOCKS

• US 20100003733A1
• Filed: 08/12/2009
• Published: 01/07/2010
• Est. Priority Date: 04/13/2004
• Status: Active Grant

• Current Assignee: Iogen Energy Corporation (Iogen Corporation)
• Original Assignee: Iogen Energy Corporation (Iogen Corporation)
• Inventors: Anand, Vijay, Rahme, Ziyad, Tolan, Jeffrey S., Foody, Brian
• Granted Patent: US 8,247,203 B2
• Time in Patent Office: Days
• US Class Current: 435/165
• CPC Class Codes: B01B 1/005 Evaporation for physical or chemical purposes; Evaporation apparatus therefor, e.g. evaporation of liquids for gas phase reactions
• CPC Class Codes: B01D 15/1821 Simulated moving beds
• CPC Class Codes: B01D 15/365 Ion-exclusion
• CPC Class Codes: B01D 61/147 Microfiltration
• CPC Class Codes: B01D 61/44 Ion-selective electrodialysis
• CPC Class Codes: C01C 1/28 Methods of preparing ammonium salts in general
• CPC Class Codes: C01D 3/04 Chlorides
• CPC Class Codes: C01D 5/04 Preparation of sulfates with the aid of sulfurous acid or sulfites, e.g. Hargreaves process pyrosulfites or metabisulfites C01D5/145
• CPC Class Codes: C01D 5/16 Purification C01D5/145 takes precedence
• CPC Class Codes: C05B 7/00 Fertilisers based essentially on alkali or ammonium orthophosphates C05B11/00 takes precedence
• CPC Class Codes: C05C 3/00 Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor
• CPC Class Codes: C05D 1/00 Fertilisers containing potassium C05D7/00 takes precedence
• CPC Class Codes: C05D 1/02 Manufacture from potassium chloride or sulfate or double or mixed salts thereof
• CPC Class Codes: C05D 5/00 Fertilisers containing magnesium C05D7/00 takes precedence
• CPC Class Codes: C05F 11/00 Other organic fertilisers
• 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 3/00 Preparation of elements or inorganic compounds except carbon dioxide recovery of carbon dioxides as by-products C12F3/02
• CPC Class Codes: C12P 7/06 Ethanol, i.e. non-beverage
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: Y02E 50/10 : Biofuels, e.g. bio-diesel

Abstract

A method for recovering inorganic salt during processing of a lignocellulosic feedstock is provided. The method comprises pretreating the lignocellulosic feedstock by adding an acid to the feedstock to produce a pretreated lignocellulosic feedstock. A soluble base is then added to the pretreated lignocellulosic feedstock to adjust the pH and produce a neutralized feedstock. The neutralized feedstock is then enzymatically hydrolyzed to produce an enzyme hydrolyzed feedstock and a sugar stream. Inorganic salt is recovered from either a stream obtained from the lignocellulosic feedstock prior to the step of pretreating, a stream obtained from the pretreated lignocellulosic feedstock, a stream obtained from the neutralized feedstock, a stream obtained from the sugar stream, or a combination of these streams. The inorganic salt may be concentrated, clarified, recovered and purified by crystallization, electrodialysis drying, or agglomeration and granulation, and then used as desired, for example as a fertilizer.

Claims

1. A method for recovering inorganic salt during processing of a lignocellulosic feedstock comprising:

a. pretreating the lignocellulosic feedstock by adding one or more than one acid to the lignocellulosic feedstock to produce a pretreated lignocellulosic feedstock;

b. adding one or more than one soluble base to the pretreated lignocellulosic feedstock to adjust the pretreated lignocellulosic feedstock to a pH of about 4.0 to about 6.0 to produce a neutralized feedstock;

c. enzymatically hydrolyzing the neutralized feedstock to produce a sugar stream and an enzyme hydrolyzed feedstock; and

d. recovering the inorganic salt from a stream produced from the lignocellulosic feedstock prior to the step of pretreating (step a.), a stream obtained from the pretreated lignocellulosic feedstock, a stream obtained from the neutralized feedstock, the sugar stream, or a combination thereof.

2. The method of claim 1, wherein the lignocellulosic feedstock is selected from the group consisting of corn stover, wheat straw, barley straw, canola straw, rice straw, oat straw, soybean stover, grass, switch grass, miscanthus, cord grass, and reed canary grass, aspen wood, sawdust, bagasse and beet pulp.

3. The method of claim 1, wherein the lignocellulosic feedstock contains from about 0.2% to about 4% (w/w) potassium.

4. The method of claim 1, wherein, in the step of recovering (step d.), the inorganic salt is recovered by ion exclusion.

5. The method of claim 4, wherein the step of recovering (step d.) is followed by crystallization of the inorganic salt, electrodialysis, drying, or agglomeration and granulation.

6. The method of claim 1, wherein, in the step of recovering (step d.), the inorganic salt comprises ammonium sulfate salts, ammonium phosphate salts, potassium sulfate salts, ammonium sulfite salts, potassium sulfite salts, sodium sulfate salts, sodium sulfite salts, magnesium sulfate, ammonium chloride, potassium chloride, magnesium chloride or a mixture thereof.

7. The method of claim 6, wherein the salt comprises ammonium sulfate salts, potassium sulfate salts, or a mixture thereof.

8. The method of claim 6, wherein the ammonium sulfite salts, sodium sulfite salts, potassium sulfite salts, or a mixture thereof, are converted to sulfate salts by oxidation before or after the step of recovering (step d.).

9. The method of claim 4, wherein the inorganic salt is concentrated by evaporation, membrane filtration, or a combination thereof prior to recovery to produce a concentrated solution comprising the inorganic salt.

10. The method of claim 9, wherein the concentrated solution is clarified by microfiltration, plate and frame filtration, or centrifugation prior to recovery.

11. The method of claim 1, wherein the step of pretreatment (step a.) comprises a method selected from the group consisting of batch dilute acid hydrolysis, continuous dilute acid hydrolysis, steam explosion and extrusion.

12. The method of claim 1, wherein, in the step of pretreatment (step a.), the one or more than one acid is selected from the group consisting of sulfuric acid, sulfurous acid, sulfur dioxide, phosphoric acid, and a combination thereof.

13. The method of claim 12, wherein the one or more than one acid is sulfuric acid.

14. The method of claim 1, wherein, in the step of adding (step b.), the one or more than one soluble base is selected from the group consisting of ammonia, ammonium hydroxide, potassium hydroxide, and sodium hydroxide.

15. The method of claim 1, wherein the step of pretreating (step a.) is performed at a temperature from about 160°

C. to about 280°

C., at a pH from about pH 0.4 to about 2.0 and/or for a time period of from about 0.1 to about 30 minutes.

16. The method of claim 1, further comprising the steps of:

e. fermenting the sugar stream to produce a fermentation broth comprising ethanol; and

f. distilling the fermentation broth to produce concentrated ethanol and still bottoms.

17. The method of claim 16, further comprising a step of recovering the inorganic salt from the still bottoms followed by purifying the inorganic salt.

18. The method of claim 17, wherein, prior to the step of recovering the inorganic salt from the still bottoms, the concentration of the still bottoms is increased by evaporation, membrane filtration, or a combination thereof, to produce concentrated still bottoms, followed by a step of ion exclusion chromatography using a simulated moving bed (SMB) process.

19. The method of claim 18, wherein the concentrated still bottoms are clarified by microfiltration, plate and frame filtration or centrifugation, prior to the step of ion exclusion chromatography.

20. The method of claim 19, wherein the step of purifying the inorganic salt comprises crystallization of the inorganic salt, electrodialysis, drying, or agglomeration and granulation.

21-32. -32. (canceled)