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-9376501-B2
Application number	US-201414207786-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 14, 2013
Publication date	Jun 28, 2016
Grant date	Jun 28, 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 in a digestion medium comprising water and an organic solvent; 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 and liberating lignin, the lignin forming a phenolics liquid phase partitioned from the digestion medium and at least a portion of the slurry catalyst accumulating in the phenolics liquid phase; removing at least a portion of the phenolics liquid phase and accumulated slurry catalyst from the digestion unit; converting at least a portion of the phenolics liquid phase into a phenolic solvent; and returning at least a portion of the phenolic solvent and the slurry catalyst to the digestion unit.

First claim

The invention claimed is:

1. A method comprising:
providing cellulosic biomass solids in a digestion medium comprising water and an organic solvent;
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, the lignin forming a phenolics liquid phase that is partitioned from the digestion medium and at least a portion of the slurry catalyst accumulating in the phenolics liquid phase as it forms;
removing at least a portion of the phenolics liquid phase and the slurry catalyst accumulated therein from the digestion unit;
converting at least a portion of the phenolics liquid phase into a phenolic solvent; and
returning at least a portion of the phenolic solvent and the slurry catalyst to the digestion unit, the phenolic solvent becoming part of the digestion medium once returned to the digestion unit, wherein the phenolic solvent and the slurry catalyst are returned to the digestion unit such that upwardly directed fluid flow is established therein;
wherein the digestion medium comprises at least one of a one-phase mixture that is partitioned from the phenolics liquid phase and a two-phase mixture that is partitioned from the phenolics liquid phase.

2. The method of claim 1 , wherein the phenolic solvent and the slurry catalyst are returned to the digestion unit while heating the cellulosic biomass solids and the digestion medium.

3. The method of claim 2 , further comprising:
heating the cellulosic biomass solids in the presence of the phenolic solvent, the molecular hydrogen, and the slurry catalyst to continue forming the alcoholic component.

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

5. The method of claim 4 , further comprising:
exposing the alcoholic component to a condensation catalyst, thereby forming a condensation reaction product.

6. The method of claim 4 , wherein the alcoholic component is admixed with the digestion medium when removed from the digestion unit.

7. The method of claim 6 , further comprising:
returning at least a portion of the alcoholic component to the digestion unit.

8. The method of claim 7 , wherein the alcoholic component is returned to the digestion unit such that upwardly directed fluid flow is established therein.

9. The method of claim 1 , wherein the upwardly directed fluid flow at least partially distributes the slurry catalyst within the cellulosic biomass solids in the digestion unit.

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

11. The method of claim 10 , wherein the one or more phenolic compounds comprises a compound selected from the group consisting of eugenol, dihydroeugenol, propoxylated phenols, methoxypropylated phenols, and any combination thereof.

12. The method of claim 1 , wherein the lignin in the phenolics liquid phase is converted into the phenolic solvent external to the digestion unit.

13. The method of claim 1 , wherein the lignin in the phenolics liquid phase is converted into the phenolic solvent by thermally depolymerizing the lignin, chemically hydrolyzing the lignin, or any combination thereof.

14. The method of claim 13 , wherein thermally depolymerizing the lignin comprises heating the phenolics liquid phase to a temperature of at least about 270° C. in the presence of molecular hydrogen and the slurry catalyst.

15. The method of claim 1 , further comprising:
measuring the viscosity of the phenolics liquid phase while converting the phenolics liquid phase into the phenolic solvent.

16. 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.

17. The method of claim 1 , wherein the slurry catalyst comprises a poison-tolerant catalyst.

18. The method of claim 17 , wherein the poison-tolerant catalyst comprises a sulfided catalyst.

Assignees

• Shell Oil Co

Inventors

• Powell Joseph Broun

Classifications

• D21C3/20 Primary

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

• D21C7/14

  Means for circulating the lye · CPC title

• C08B1/003 Primary

  Preparation of cellulose solutions, i.e. dopes, with different possible solvents, e.g. ionic liquids (solutions used in the manufacture of monocomponent artificial filaments or cellulose or derivatives thereof D01F2/02) · CPC title

• Y02P30/20

  using bio-feedstock · 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