Process for hydrolyzing a pretreated feedstock and recovering lignin

Patent metadata

Field	Value
Publication number	US-10087476-B2
Application number	US-201415034867-A
Country	US
Kind code	B2
Filing date	Dec 4, 2014
Priority date	Dec 6, 2013
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A process for hydrolyzing a pretreated lignocellulosic feedstock is disclosed herein. The process comprises hydrolyzing the pretreated lignocellulosic feedstock with an enzyme mixture comprising at least cellulase enzymes to produce a hydrolyzed slurry comprising glucose and lignin solids. The hydrolyzing is conducted in the presence of a polymer, such as an aliphatic polyether. A solids-liquid separation is conducted to recover lignin solids from a process stream comprising the lignin solids and the polymer. A process stream is then obtained comprising recovered lignin solids resulting from the solids-liquid separation. Also provided are processes for recovering the polymer from the lignin solids and/or from solution.

First claim

The invention claimed is:

1. A process for hydrolyzing a pretreated lignocellulosic feedstock and recovering lignin solids comprising:
(i) hydrolyzing the pretreated lignocellulosic feedstock with an enzyme mixture comprising at least cellulase enzymes to produce a hydrolyzed slurry comprising glucose and lignin solids, said hydrolyzing being conducted in the presence of a polymer that binds or associates with the lignin solids;
(ii) conducting a solids-liquid separation to recover lignin solids from a process stream comprising the lignin solids and the polymer;
(iii) obtaining a process stream comprising recovered lignin solids resulting from the solids-liquid separation of step (ii), and
(iv) recovering at least a portion of the polymer from the recovered lignin solids of step (iii) comprising adding a chemical extractant selected from alcohol or alkali for extracting the at least a portion of the polymer, and further recovering the chemical extractant and recycling both the recovered polymer and the chemical extractant in the process.

2. The process of claim 1 , wherein the polymer that binds or associates with the lignin solids is a non-ionic polymer.

3. The process of claim 2 , wherein the non-ionic polymer is a water-soluble polymer.

4. The process of claim 3 , wherein the water-soluble polymer is a polyether or a surfactant comprising a polyether.

5. The process of claim 4 , wherein the polyether is paraformaldehyde, polyethylene glycol, polypropylene glycol, polytetramethylene glycol or a substituted aliphatic polyether.

6. The process of claim 1 , wherein the polymer is added at a concentration of 2% to 20% by weight based on the weight of undissolved pretreated solids.

7. The process of claim 1 , wherein in the step of conducting a solids-liquid separation to recover the lignin solids from a process stream comprising the lignin solids and the polymer, at least 50 wt % of the process stream is fed to the solids-liquid separation.

8. The process of claim 1 , wherein the solids-liquid separation is filtration.

9. The process of claim 1 , wherein the process stream of step (ii) is a fermentation broth or a still bottoms stream.

10. The process of claim 1 , wherein the lignin solids in the process stream of step (ii) comprises dissolved lignin.

11. The process of claim 1 , wherein the chemical extractant in step (iv) is an alcohol.

12. The process of claim 11 , wherein the process stream comprising the lignin solids and the polymer is heat treated, treated with lime, or a combination thereof, prior to recovery of the polymer.

13. The process of claim 1 , further comprising recovering at least another portion of the polymer from solution of an aqueous process stream, said aqueous process stream obtained from the solids-liquid separation in step (ii).

14. The process of claim 1 , wherein conducting the solids-liquid separation comprises filtering the process stream when the process stream is at a temperature between 55° C. and 200° C.

15. The process of claim 1 , wherein the polymer comprises polyethylene glycol.

16. The process of claim 11 , wherein the alcohol is ethanol.

17. The process of claim 11 , wherein the alcohol is methanol.

18. The process of claim 14 , wherein the temperature is at least 80° C. and less than 200° C.

19. A process for producing an alcohol from a lignocellulosic feedstock comprising:
hydrolyzing a pretreated lignocellulosic feedstock with an enzyme mixture comprising at least cellulase enzymes to produce a hydrolyzed slurry comprising glucose and lignin solids, said hydrolyzing being conducted in the presence of a polymer that binds or associates with the lignin solids;
(ii) fermenting the glucose to produce a fermentation beer comprising the alcohol and then concentrating the alcohol;
(iii) conducting a solids-liquid separation to recover the lignin solids from a process stream comprising the lignin solids and the polymer;
(iv) obtaining a process stream comprising recovered lignin solids resulting from the solids-liquid separation of step (iii), and
(v) recovering at least a portion of the polymer from the recovered lignin solids of step (iii) comprising adding a chemical extractant selected from an alcohol or alkali for extracting the at least a portion of the polymer, further recovering the chemical extractant and recycling both the recovered polymer and the chemical extractant in the process.

20. The process of claim 19 , wherein the process stream comprising the lignin solids and the polymer in step (iii) is the hydrolyzed slurry, the fermentation beer, a still bottoms stream remaining from concentrating the alcohol, or a combination thereof.

Assignees

• Iogen Corp

Inventors

• Foody Brian E
• Martens Kristin
• Foody Patrick J
• Tolan Jeffrey S

Classifications

• C12P19/02

  Monosaccharides (2-ketogulonic acid C12P7/60) · CPC title

• D21C3/04

  with acids, acid salts or acid anhydrides {(D21C3/003 and D21C3/222 take precedence)} · CPC title

• C08H6/00

  Macromolecular compounds derived from lignin, e.g. tannins, humic acids · CPC title

• Y02E50/16

  Cross-Sectional Technologies · mapped topic

• D21C11/0007

  Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for (volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042) · CPC title