Pre-treatment of bales of feedstock

• US 20060068475A1
• Filed: 09/30/2004
• Published: 03/30/2006
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Iogen Energy Corporation (Iogen Corporation)
• Original Assignee: Iogen Energy Corporation (Iogen Corporation)
• Inventors: Foody, Brian
• Granted Patent: US 7,198,925 B2
• Time in Patent Office: Days
• US Class Current: 435/105
• CPC Class Codes: C12P 19/02 Monosaccharides 2-ketogulonic acid C12P7/60
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

The present invention is directed to a method of pre-treating a lignocellulosic feedstock. The lignocellulosic feedstock comprises cereal straw, stover, or grass. One or more than one bale of lignocellulosic feedstock is conveyed into a pre-treatment reactor. Steam and acid are added to the bales and are maintained at a temperature, acid concentration, and for a time sufficient to hydrolyze hemicellulose to xylose and increase susceptibility of cellulose to digestion by cellulase enzymes, thus producing a pre-treated feedstock. The pre-treated feedstock is then removed from the pre-treatment reactor.

Claims

1. A method for conversion of a lignocellulosic feedstock to glucose comprising the steps of:

a. conveying one or more than one bale of the lignocellulosic feedstock into a pre-treatment reactor;

b. adding steam and acid to the bale, the steam and acid maintained at a temperature, acid concentration, and for a time sufficient to hydrolyze hemicellulose to xylose and increase susceptibility of cellulose to digestion by cellulase enzymes, to produce a pre-treated feedstock;

c. depressurizing the pre-treatment reactor;

d. removing the pre-treated feedstock from the pre-treatment reactor; and

e. hydrolysing the pre-treated feedstock using cellulase enzymes to produce glucose.

2. The method of claim 1, wherein the lignocellulosic feedstock is a cereal straw, stover;

and a grass, or any combination thereof.

3. The method of claim 2, wherein the cereal straw is a wheat straw, barley straw, canola straw, or oat straw;

the stover is corn stover or soybean stover; and

the grass is switch grass, miscanthus, cord grass, or reed canary grass.

4. The method of claim 1, wherein the bale is soaked in water prior to the step of adding (step b).

5. The method of claim 1, wherein the bale is cut prior to the step of conveying (step a).

6. The method of claim 1, wherein after the step of conveying (step a) and prior to the step of adding (step b), the feedstock is pre-steamed.

7. The method of claim 1, wherein in the step of adding (step b), the acid is selected from the group consisting of sulfuric acid, sulfurous acid, sulfur dioxide, and a combination thereof.

8. The method of claim 1, wherein in the step of adding (step b), the temperature is about 160°

C. to about 280°

C., the acid concentration is about 0% to about 12% weight of acid on weight of feedstock, and the time is about 5 seconds to about 10 minutes.

9. The method of claim 1 wherein in the step of conveying (step a) the lignocellulosic feedstock in the pre-treatment reactor is at least 50% solids.

10. A method for pre-treating a lignocellulosic feedstock comprising the steps of:

a. conveying one or more than one bale of lignocellulosic feedstock into a pre-treatment reactor, the lignocellulosic feedstock comprising cereal straw, stover, or grass;

b. adding steam and acid to the bale, the steam and acid maintained at a temperature, acid concentration, and for a time sufficient to hydrolyze hemicellulose to xylose and increase susceptibility of cellulose to digestion by cellulase enzymes, to produce a pre-treated feedstock;

c. depressurizing the pre-treatment reactor; and

d. removing the pre-treated feedstock from the pre-treatment reactor.

11. The method of claim 10, wherein the lignocellulosic feedstock is a cereal straw, stover;

and a grass, or any combination thereof.

12. The method of claim 11, wherein the cereal straw is a wheat straw, barley straw, canola straw, or oat straw;

the stover is corn stover or soybean stover; and

the grass is switch grass, miscanthus, cord grass, or reed canary grass.

13. The method of claim 10, wherein the bale is soaked in water prior to the step of adding (step b).

14. The method of claim 10, wherein the bale is cut prior to the step of conveying (step a).

15. The method of claim 10, wherein after the step of conveying (step a) and prior to the step of adding (step b), the feedstock is pre-steamed.

16. The method of claim 10, wherein in the step of adding (step b), the acid is selected from the group consisting of sulfuric acid, sulfurous acid, sulfur dioxide, and a combination thereof.

17. The method of claim 10, wherein in the step of adding (step b), the temperature is about 160°

C. to about 280°

C., the acid concentration is about 0% to about 12% weight of acid on weight of feedstock, and the time is about 5 seconds to about 10 minutes.

18. The method of claim 10, wherein in the step of conveying (step a) the lignocellulosic feedstock in the pre-treatment reactor is at least 50% solids.