Process of treating lignocellulosic material to produce bio-ethanol

• US 7,189,306 B2
• Filed: 02/24/2003
• Issued: 03/13/2007
• Est. Priority Date: 02/22/2002
• Status: Expired due to Fees

• Current Assignee: Gibson W. Gervais
• Original Assignee: Gibson W. Gervais
• Inventors: Gervais, Gibson W.
• Primary Examiner(s): HUG, ERIC J
• Application Number:
  US10/373,588
• Publication Number:
  US 20040016525A1
• Time in Patent Office: 1,478 Days
• Field of Search: 162/21, 162/22, 162/65, 162/78, 162/90, 162/79, 162/68, 162 14- 16, 162/18, 162/56, 162/24, 162/29, 426/447, 426/448, 127/36, 127/37, 435/161, 536/1.1
• US Class Current: 162/21
• CPC Class Codes: C12P 7/10 substrate containing cellulosic material
• CPC Class Codes: C13K 1/02 obtained by saccharification of cellulosic materials manufacture of fodder A23K10/32
• CPC Class Codes: C13K 13/002 Xylose
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

This invention relates to a process of treating a lignocellulosic material to produce bio-ethanol. The process includes the steps of: (a) exposing the lignocellulosic material to conditions including a pH not less than about 8, and steam at a first pressure, to produce a step (a) product; (b) explosively discharging the step (a) product to a second pressure less than the first pressure to produce a step (b) product; and (c) further processing the step (b) product to produce bio-ethanol and other co-products. In another embodiment, the invention relates to a conical auger fractionation column. The fractionation column includes a column body having an input and an output. A conical filter is positioned inside the column body, the filter having a larger diameter end directed toward the input and a smaller diameter end directed toward the output. A conical auger is positioned inside the conical filter, the conical auger having an outer diameter which is approximately the same as an inner diameter of the conical filter. The auger and filter are adapted to cooperate to separate cellulosic solids from a liquid stream in a process of producing bio-ethanol from a lignocellulosic material.

Claims

1. A process of treating a lignocellulosic material to produce bio-ethanol, the process comprising the steps of:

(a) grinding a quantity of untreated lignocellulosic material;

(b) exposing the ground and untreated lignocellulosic material of step (a) to conditions including a pH not less than about 8, and steam at a first pressure, to produce a step (b) product;

(c) explosively discharging the step (b) product to a second pressure less than the first pressure to produce a slurry containing solids; and

(d) further processing said slurry by passing said slurry through a device to separate the cellulosic solids from a liquid stream, said device increasing pressure on the separated solids as the solids pass through said device.

2. A process according to claim 1 wherein the first pressure is a pressure of from about 190 psig to about 450 psig, and wherein the second pressure is atmospheric pressure.

3. A process according to claim 1 wherein the pH is not less than about 11.

4. A process according to claim 1 wherein the conditions of step (a) further include a temperature not lower than about 190°

C.

5. A process according to claim 1 wherein the conditions of step (a) further include hyperbaric oxygen.

6. A process according to claim 1 wherein the conditions of step (a) further include peroxide.

7. A process according to claim 1 wherein the conditions of step (a) further include a metallic catalyst.

8. A process according to claim 1 wherein the explosive discharge has a Ro of from about 2.5 to about 3.7.

9. A process according to claim 1 wherein step (a) is conducted from a time of from about 1 minute to about 5 minutes.

10. A process according to claim 1 wherein steps (a) and (b) are conducted in a continuous process.

11. A process according to claim 1 wherein the further processing of step (c) includes simultaneous saccharification and co-fermentation.

12. A process of treating a lignocellulosic material to produce bio-ethanol, the process comprising the steps of:

(a) grinding a quantity of untreated lignocellulosic material;

(b) exposing the ground and untreated lignocellulosic material of step (a) to conditions including a pH not less than about 8, and steam at a first pressure, to produce a step (b) product;

(c) explosively discharging the step (b) product to a second pressure less than the first pressure to produce a slurry containing solids;

(d) passing the slurry through a fractionation device to separate the cellulosic solids from a liquid stream, the device increasing pressure on the separated solids as the solids pass through the device to increase separation efficiency; and

(e) further processing the cellulosic solids and the liquid stream.

13. A process according to claim 12 wherein the fractionation device includes a conical filter through which the slurry is forced to separate the solids from the liquid stream.

14. A process according to claim 13 wherein the fractionation device includes a conical auger inside the conical filter to force the slurry through the filter.

15. A process according to claim 14 wherein the conical auger has an outer diameter which is approximately the same as an inner diameter of the conical filter.

16. A process according to claim 15 wherein the auger turns to displace solids from the surface of the screen and to force material through the conical filter and outlet holes.

17. A process of treating a lignocellulosic material to produce bio-ethanol, the process comprising the steps of:

(a) grinding a quantity of untreated lignocellulosic material;

(b) pretreating the ground and untreated lignocellulosic material of step (a) with an alkaline material to raise its pH to not less than about 8;

then

(c) exposing the lignocellulosic material to steam at a first pressure to produce a step (c) product;

then

(d) explosively discharging the step (c) product to a second pressure less than the first pressure to produce a step (d) product in the form of a slurry having solids; and

then

(e) further processing said slurry by passing said slurry through a device to separate the cellulosic solids from a liquid stream, said device increasing pressure on the separated solids as the solids pass through said device.