METHOD AND APPARATUS FOR TREATING A CELLULOSIC FEEDSTOCK

• US 20100024808A1
• Filed: 07/29/2008
• Published: 02/04/2010
• Est. Priority Date: 07/24/2008
• Status: Active Grant

• Current Assignee: Abengoa Bioenergy New Technologies, LLC (Abengoa SA)
• Original Assignee: Sunopta Bioprocess Inc. (Lallemand Inc.)
• Inventors: Burke, Murray J., Hillier, Sunalie N.
• Granted Patent: US 8,449,680 B2
• Time in Patent Office: Days
• US Class Current: 127/1
• CPC Class Codes: B01J 19/18 Stationary reactors having moving elements inside B01J19/08, B01J19/26 take precedence
• CPC Class Codes: C08B 1/00 Preparatory treatment of cellulose for making derivatives thereof , e.g. pre-treatment, pre-soaking, activation
• CPC Class Codes: C12M 45/02 by mechanical forces; Stirring; Trituration; Comminuting crushing, pulverizing, disintegrating in general B02C
• CPC Class Codes: C12M 45/20 Heating; Cooling heating or cooling apparatus for laboratory uses B01L7/00
• CPC Class Codes: C12P 2201/00 Pretreatment of cellulosic or lignocellulosic material for subsequent enzymatic treatment or hydrolysis
• 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: D21B 1/16 in the presence of chemical agents
• CPC Class Codes: D21B 1/22 with screw feed
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A method and apparatus for pre-treating a cellulosic feedstock are disclosed. Embodiments of the method comprise conveying the cellulosic feedstock through an enclosed volume, adding moisture to the cellulosic feedstock simultaneously at multiple spaced-apart moisture injection points as the cellulosic feedstock travels through the volume, and heating the cellulosic feedstock as it travels through the volume to obtain a heated moistened feedstock. Embodiments of the apparatus comprise a shell defining a treatment chamber having a lower inner surface. The treatment chamber has an inlet and an outlet spaced longitudinally apart from the inlet to define an axial length. A conveyance member is housed within the shell and is configured to sweep the lower inner surface. A plurality of injection ports are provided in at least one of the shell and the conveyance member.

Claims

1. A method for treating a cellulosic feedstock comprising:

a) conveying the cellulosic feedstock having a moisture content through an enclosed volume;

b) adding moisture to the cellulosic feedstock simultaneously at multiple spaced-apart moisture injection points as the cellulosic feedstock travels through the volume; and

,

c) heating the cellulosic feedstock as it travels through the volume and obtaining a heated moistened feedstock.

2. The method of claim 1, wherein the volume comprises an impregnation chamber defined by chamber walls having an inner surface, and the impregnation chamber extends longitudinally along an axial length from an inlet to an outlet, and the cellulosic feedstock is urged through the chamber by a conveyance member.

3. The method of claim 1, wherein step (b) comprises adding moisture to increase the moisture content of the cellulosic feedstock from about 5-15 wt % to about 45-55 wt %.

4. The method of claim 2, wherein the plurality of injection points comprises a plurality of ports extending through the chamber wall commencing proximate the inlet and the method further comprising introducing moisture to the cellulosic feedstock at least during its initial travel through the impregnation chamber.

5. The method of claim 4, wherein the injection points are provided in a first third of the axial length of the impregnation chamber.

6. The method of claim 3, further comprising adding heated water as at least part of the moisture.

7. The method of claim 3, further comprising adding a catalyst with the moisture.

8. The method of claim 3, wherein step (c) comprises heating the cellulosic feedstock from less than about 30°

Celsius at the inlet, to at least about 65°

Celsius at the outlet.

9. The method of claim 5, wherein step (c) comprises heating the cellulosic feedstock to about 50-70°

Celsius at the outlet.

10. The method of claim 1, wherein step (c) comprises heating the moisture prior to contacting the moisture with the feedstock.

11. The method of claim 2, wherein step (c) comprises indirectly heating the cellulosic feedstock by heating at least one of the chamber walls and the conveyance member.

12. The method of claim 2, wherein the conveyance member extends longitudinally through the impregnation chamber and is configured to urge the cellulosic feedstock axially through the impregnation chamber as the conveyance member rotates.

13. The method of claim 2, wherein the conveyance member comprises a rotary shaft extending longitudinally through the impregnation chamber and a plurality of paddles extending radially outwardly from the shaft, and the method further comprises rotating the shaft to urge the cellulosic feedstock axially through the impregnation chamber.

14. The method of claim 12, wherein the conveyance member includes moisture injection points and the method further comprises introducing moisture to the volume as the conveyance member rotates.

15. The method of claim 13, wherein the conveyance member includes a fluid conduit extending longitudinally through the shaft and a plurality of paddle ducts in communication with the fluid conduit and extending through the paddle to an outer surface thereof, and wherein the step of adding moisture to the cellulosic feedstock comprises injecting moisture into the feedstock through the paddle ducts.

16. The method of claim 2, wherein the conveyance member comprises a rotary shaft extending longitudinally through the impregnation chamber and a plurality of paddles extending radially outwardly from the shaft and the paddles are relative to the impregnation chamber to sweep at least a lower circumferential portion of the inner surface of the chamber walls when the feedstock is conveyed through the chamber.

17. The method of claim 2, wherein the conveyance member comprises a rotary shaft extending longitudinally through the impregnation chamber and a plurality of paddles extending radially outwardly from the shaft and the paddles are spaced and configured such that the lower circumferential portion of the chamber is swept along generally the entire axial length of the chamber as the feedstock is conveyed through the chamber.

18. The method of claim 1, wherein in the volume has a residence time of less than about ten minute.

19. The method of claim 1, further comprising monitoring the moisture content of the feedstock and introducing an amount of moisture to produce a predetermined moisture content of the heated moistened feedstock.

20. The method of claim 1, further comprising providing a feedstock having a moisture content of less than about 45 wt % comprising fibers that have a length in the range of about 4 mm to about 7 mm.

21. The method of claim 1, further comprising subsequently subjecting the cellulosic feedstock to a downstream hydrolysis process.

22. An apparatus for treating a cellulosic fiber feedstock, comprising:

a) a shell defining a treatment chamber having a lower inner surface, the shell having an inlet and an outlet spaced longitudinally apart from the inlet to define an axial length;

b) a conveyance member housed within the shell and configured to sweep the lower inner surface; and

,

c) a plurality of injection ports provided in at least one of the shell and the conveyance member.

23. The apparatus of claim 22, wherein the plurality of injection ports comprises about 1 to 20 injection ports.

24. The apparatus of claim 22, wherein the plurality of injection ports are positioned along at least a first portion of the axial length of the shell, the first portion extending from the inlet towards the outlet.

25. The apparatus of claim 22, wherein the conveyance member comprises at least a first rotary shaft and a plurality of paddles joined to the first shaft and extending radially outwardly therefrom.

26. The apparatus of claim 25, wherein the paddles and the lower inner surface are configured to maintain a minimum space between the paddles and the lower inner surface of less than 6.5 mm.

27. The apparatus of claim 25, wherein the paddles comprise blades, and the blades are generally planar members, having a radially inner edge attached to stem, a radially outer edge opposite the radially inner edge, and opposing first and second side edges extending between the radially inner and outer edges and the radially outer edge is curved to match an arc swept by the outer edge when the first shaft rotates.

28. The apparatus of claim 27, wherein each blade is canted, wherein the first side edge is axially nearer the outlet and rotationally trailing relative to a second side edge.

29. The apparatus of claim 28, wherein axially adjacent paddles extend from the shaft at different angular positions around to the shaft axis.

30. The apparatus of claim 28, wherein the first side edge of one paddle axially overlaps the second side edge of a next adjacent paddle.

31. The apparatus of claim 25, wherein the conveyance member comprises a second shaft, spaced transversely apart from and extending generally parallel to the first shaft and the lower inner surface is scallop shaped in transverse section.

32. The apparatus of claim 25, wherein the conveyance member comprises a second shaft, spaced transversely apart from and extending generally parallel to the first shaft, each shaft having a plurality of paddles attached thereto, and the lower inner surface has a first portion below the first shaft and a second portion below the second shaft wherein, when viewed in transverse cross section, each the first portion defines an arc at a constant distance to the first shaft and the second portion defines an arc at a constant distance to the second shaft.

33. The apparatus of claim 32, wherein the second shaft rotates in an opposite direction to the first shaft.

34. The apparatus of claim 25, further comprising a first heated fluid supply in fluid communication with the injection ports.

35. The apparatus of claim 34, wherein the first heated fluid supply comprises water heated to from about 60 to about 70°

Celsius.

36. The apparatus of claim 35, wherein the first heated fluid supply comprises a catalyst.

37. The apparatus of claim 35, further comprising a jacket surrounding at least a portion of the shell and defining an enclosure between the jacket and the shell.

38. The apparatus of claim 37, further comprising a second heated fluid supply associated with the enclosure.

39. The apparatus of claim 38, wherein the second heated fluid supply comprises steam.

40. The apparatus of claim 38, wherein the shaft comprises a conduit extending longitudinally therethrough.

41. The apparatus of claim 40, wherein the conveyance member includes injection ports.

42. The apparatus of claim 41, wherein at least one of the stem and the paddles comprise injection ports.

43. The apparatus of claim 22, further comprising a moisture sensor that measures the moisture content of the cellulosic fiber feedstock and a controller operatively controlling to an amount of moisture introduced through the injection ports whereby a predetermined moisture content of the cellulosic fiber feedstock is obtained at the outlet.

44. The apparatus of claim 43, wherein the moisture sensor is upstream of the inlet.

45. The apparatus of claim 43, wherein the predetermined moisture content of the cellulosic fiber feedstock is from 45 to 55 wt %.