Method of processing ethanol byproducts and related subsystems

• US 20060041152A1
• Filed: 05/05/2005
• Published: 02/23/2006
• Est. Priority Date: 08/17/2004
• Status: Active Grant

• Current Assignee: GS Cleantech Corporation (Greenshift Corporation)
• Original Assignee: GS Cleantech Corporation (Greenshift Corporation)
• Inventors: Cantrell, David Fred, Winsness, David J.
• Granted Patent: US 7,601,858 B2
• Time in Patent Office: Days
• US Class Current: 554/8
• CPC Class Codes: B01D 3/004 by continuous methods
• CPC Class Codes: C11B 1/00 Production of fats or fatty oils from raw materials
• CPC Class Codes: C11B 13/00 Recovery of fats, fatty oils or fatty acids from waste materials
• CPC Class Codes: C11B 3/001 by a combination of two or more of the means hereafter
• CPC Class Codes: C12F 3/10 from distillery slops
• CPC Class Codes: Y02W 30/74 Recovery of fats, fatty oils, fatty acids or other fatty substances, e.g. lanolin or waxes

Abstract

In one aspect of the invention, a method recovers oil from a concentrated byproduct, such as evaporated thin stillage formed during a dry milling process used for producing ethanol. The method includes forming a concentrate from the byproduct and recovering oil from the concentrate. The step of forming the concentrate may comprise evaporating the byproduct. Further, the step of separating the oil from the concentrate may comprise using a centrifuge and, in particular, a disk stack centrifuge. Other aspects of the invention include related methods and subsystems for recovering oil from thin stillage.

Claims

1. A method of processing a concentrated byproduct of a dry milling process for producing ethanol, comprising recovering oil from the concentrated byproduct.

2. The method of claim 1, wherein the byproduct comprises thin stillage, and the method further includes the step of evaporating the thin stillage to form the concentrated byproduct having a moisture content of greater than 15% and less than about 90% by weight before the recovering step.

3. The method of claim 1, wherein the recovering step comprises separating the oil from the concentrated byproduct using a disk stack centrifuge.

4. The method of claim 1, wherein the recovering step is performed on the concentrated byproduct at a temperature of between about 150 and 212°

F.

5. The method of claim 1, wherein the recovering step is performed on the concentrated byproduct at a temperature of about 180°

F.

6. The method of claim 1, wherein the recovering step is performed on the concentrated byproduct having a pH of between about 3 and 6.

7. The method of claim 1, wherein the recovering step is performed on the concentrated byproduct having a pH of between about 3.5 and 4.5.

8. The method of claim 1, wherein the recovering step is performed on the concentrated byproduct having a moisture content greater than 15% by weight.

9. The method of claim 1, wherein the recovering step is performed on the concentrated byproduct having a moisture content between about 60-85%.

10. The method of claim 1, wherein the step of recovering the oil from the concentrated byproduct produces syrup, and the method further includes the step of recovering oil from the syrup.

11. A method of processing concentrated thin stillage created by a dry milling process for producing ethanol, comprising recovering oil from the concentrated thin stillage having a moisture content of greater than 15% by weight.

12. The method of claim 11, wherein the recovering step comprises separating the oil from the concentrated thin stillage using a disk stack centrifuge.

13. The method of claim 11, further including the step of drying the concentrated thin stillage after the recovering step.

14. A method of recovering oil from thin stillage, comprising:

evaporating the thin stillage to create a concentrate having a moisture content of greater than 15% by weight and less than about 90% by weight; and

centrifuging the concentrate to recover oil.

15. The method according to claim 14, wherein the step of centrifuging the concentrate comprises using a disk stack centrifuge.

16. A method of processing whole stillage, comprising:

recovering thin stillage from the whole stillage, the thin stillage including oil and solids;

concentrating the thin stillage including the solids; and

recovering oil from the concentrate.

17. The method of claim 16, wherein the step of recovering the thin stillage includes using a separator selected from the group consisting of a press, extruder, a decanter centrifuge, and a screen centrifuge.

18. The method of claim 16, wherein the concentrating step comprises processing the thin stillage to a temperature of between about 150 and 212°

F., a pH of between about 3 and 6, and a moisture content of less than 90%.

19. The method of claim 16, wherein the step of recovering oil comprises separating the oil from the concentrate using a centrifuge.

20. The method of claim 16, wherein the recovering and concentrating steps are performed in a continuous fashion.

21. The method of claim 16, further including the step of drying the concentrate after the step of recovering the oil.

22. In a system for producing ethanol by dry milling and creating thin stillage as a byproduct, a subsystem comprising:

an evaporator for evaporating the thin stillage to form a concentrate; and

a centrifuge for receiving the concentrate and recovering oil therefrom.

23. The subsystem according to claim 22, wherein the concentrate has a moisture content of less than about 90% by weight.

24. The subsystem of claim 22, wherein the centrifuge is a disk stack centrifuge.

25. In a system for producing ethanol by dry milling and creating thin stillage as a byproduct, a subsystem comprising:

an evaporator for evaporating the thin stillage to form a concentrate; and

means for recovering oil from the concentrate.

26. The subsystem of claim 25, wherein the recovering means comprises a centrifuge.

27. The subsystem of claim 25, wherein the recovering means comprises a disk stack centrifuge.

28. In combination, a concentrate formed from thin stillage including oil and a centrifuge for removing at least a portion of the oil from the concentrate.

29. The combination of claim 28, wherein the concentrate has a moisture content of greater than 15% by weight and less than about 90% by weight.

30. The combination of claim 28, wherein the centrifuge is selected from the group consisting of a self-cleaning bowl type of disk stack centrifuge, a nozzle bowl type of disk stack centrifuge, and a horizontal centrifugal decanter.