Methods for digestion of cellulosic biomass solids in the presence of a phenolic solvent generated in situ from lignin

Patent metadata

Field	Value
Publication number	US-9458247-B2
Application number	US-201414207945-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 14, 2013
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

Digestion of cellulosic biomass solids can be enhanced in the presence of a phenolic solvent. Methods for digesting cellulosic biomass solids can comprise providing cellulosic biomass solids containing up to about 50% water by mass in a digestion medium comprising about 50% or more of an organic solvent by volume; heating the cellulosic biomass solids and the digestion medium in a digestion unit in the presence of molecular hydrogen and a slurry catalyst capable of activating molecular hydrogen, thereby forming an alcoholic component derived from the cellulosic biomass solids and liberating lignin therefrom; wherein the digestion medium and the water form a biphasic mixture in which the alcoholic component, slurry catalyst, and lignin are contained; removing at least a portion of the biphasic mixture from the digestion unit; converting at least a portion of the lignin into a phenolic solvent; and returning the phenolic solvent to the digestion unit.

First claim

The invention claimed is:

1. A method comprising:
providing cellulosic biomass solids in a digestion medium comprising about 50% or more of an organic solvent by volume, the cellulosic biomass solids comprising water in an amount up to about 50% by mass;
heating the cellulosic biomass solids and the digestion medium in a digestion unit in the presence of molecular hydrogen and a slurry catalyst capable of activating molecular hydrogen, thereby forming an alcoholic component derived from the cellulosic biomass solids and liberating lignin from the cellulosic biomass solids into the digestion medium;
wherein the water from the cellulosic biomass solids forms a biphasic mixture with the digestion medium as the cellulosic biomass solids are heated, the biphasic mixture comprising an organic phase and an aqueous phase;
removing at least a portion of the biphasic mixture from the digestion unit, the biphasic mixture containing the alcoholic component, the lignin and the slurry catalyst;
converting at least a portion of the lignin into a phenolic solvent; and
returning at least a portion of the phenolic solvent to the digestion unit while heating the cellulosic biomass solids and the digestion medium.

2. The method of claim 1 , wherein at least a portion of the slurry catalyst accumulates in the aqueous phase of the biphasic mixture.

3. The method of claim 2 , further comprising:
after removing the biphasic mixture from the digestion unit, separating the aqueous phase from the organic phase.

4. The method of claim 3 , further comprising:
after separating the aqueous phase from the organic phase, separating the slurry catalyst from at least a portion of the aqueous phase.

5. The method of claim 4 , wherein separating the slurry catalyst from at least a portion of the aqueous phase comprises performing a cross-flow filtration on the aqueous phase.

6. The method of claim 4 , further comprising:
after separating the slurry catalyst from at least a portion of the aqueous phase, returning a portion of the aqueous phase containing the slurry catalyst to the digestion unit.

7. The method of claim 6 , wherein the aqueous phase and the slurry catalyst are returned to the digestion unit such that upwardly directed fluid flow is established therein.

8. The method of claim 4 , wherein the portion of the aqueous phase separated from the slurry catalyst also contains at least a portion of the alcoholic component or other water-soluble organic compound therein.

9. The method of claim 8 , further comprising:
exposing the alcoholic component or other water-soluble organic compound from the aqueous phase to a condensation catalyst, thereby forming a condensation reaction product.

10. The method of claim 9 , further comprising:
prior to exposing the alcoholic component or other water-soluble organic compound from the aqueous phase to the condensation catalyst, separating the alcoholic component or other water-soluble organic compound from the aqueous phase.

11. The method of claim 10 , wherein separating the alcoholic component or other water-soluble organic compound from the aqueous phase comprises performing an extraction of the aqueous phase with an organic extraction solvent.

12. The method of claim 11 , wherein the organic extraction solvent comprises the condensation reaction product, which is recirculated to the aqueous phase following its formation.

13. The method of claim 9 , further comprising:
returning at least a portion of the condensation reaction product to the digestion unit while heating the cellulosic biomass solids and the digestion medium.

14. The method of claim 13 , wherein the condensation reaction product is returned to the digestion unit as an upwardly directed fluid flow.

15. The method of claim 2 , wherein the organic phase of the biphasic mixture contains the lignin, the organic solvent, the phenolic solvent, and the remainder of the slurry catalyst.

16. The method of claim 15 , further comprising:
after removing the biphasic mixture from the digestion unit, separating the aqueous phase from the organic phase.

17. The method of claim 16 , wherein the lignin is converted into the phenolic solvent after separating the aqueous phase from the organic phase.

18. The method of claim 16 , further comprising:
performing a cross-flow filtration on the organic phase before returning the phenolic solvent to the digestion unit.

19. The method of claim 1 , wherein the phenolic solvent is returned to the digestion unit such that upwardly directed fluid flow is established therein.

20. The method of claim 1 , wherein the organic solvent comprises an alcohol or a ketone that is not fully miscible with water.

21. The method of claim 1 , wherein the organic solvent comprises one or more phenolic compounds.

22. The method of claim 21 , wherein the one or more phenolic compounds are selected from the group consisting of eugenol, dihydroeugenol, propoxylated phenols, methoxypropoxylated phenols, and any combination thereof.

23. The method of claim 1 , wherein the lignin is converted into the phenolic solvent external to the digestion unit.

24. The method of claim 23 , wherein the lignin is converted into the phenolic solvent by thermally depolymerizing the lignin, chemically hydrolyzing the lignin, or any combination thereof.

25. The method of claim 24 , wherein thermally depolymerizing the lignin comprises heating the lignin to a temperature of at least about 270° C. in the presence of molecular hydrogen and the slurry catalyst.

26. The method of claim 1 , further comprising:
removing at least a portion of the alcoholic component from the digestion unit.

27. The method of claim 26 , further comprising:
exposing the alcoholic component to a condensation catalyst, thereby forming a condensation reaction product.

28. The method of claim 27 , further comprising:
returning a portion of the condensation reaction product to the digestion unit while heating the cellulosic biomass solids and the digestion medium.

29. The method of claim 28 , wherein the condensation reaction product is returned to the digestion unit as an upwardly directed fluid flow.

30. The method of claim 1 , wherein the alcoholic component is formed by a catalytic reduction reaction of soluble carbohydrates, the soluble carbohydrates being derived from the cellulosic biomass solids.

Assignees

• Shell Oil Co

Inventors

• Powell Joseph Broun
• Denton Edward James
• Komplin Glenn Charles

Classifications

• D21C3/20 Primary

  with organic solvents {or in solvent environment} · CPC title

• Y02P30/20

  using bio-feedstock · CPC title

• D21C7/14

  Means for circulating the lye · CPC title

• 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

• D21C3/222

  Use of compounds accelerating the pulping processes · CPC title