Biomass conversion systems providing integrated stabilization of a hydrolysate using a slurry catalyst following biomass pretreatment and methods for use thereof

Inactive Publication Date: 2014-01-02
SHELL OIL CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention is a new patent that can be adapted in different ways and practiced in different ways. The illustrative embodiments disclosed herein can be modified, combined, or changed in other ways. The invention is not limited to the specific details and can be practiced in different ways. The numbers and ranges disclosed herein are meant to include every possible number and range. The invention is designed to achieve specific goals and advantages. The word "a" in the patent text refers to more than one element and the invention can be used with or without certain elements. The patent text is used to explain the invention and its advantages.

Problems solved by technology

The complex mixture of constituents that are co-present with the cellulose can make its processing difficult, as discussed hereinafter.
Despite promise and intense interest, the development and implementation of bio-based fuel technology has been slow.
Existing technologies have heretofore produced fuels having a low energy density (e.g., bioethanol) and / or that are not fully compatible with existing engine designs and transportation infrastructure (e.g., methanol, biodiesel, Fischer-Tropsch diesel, hydrogen, and methane).
However, fermentation processes are typically slow, require large volume reactors, and produce an initial reaction product having a low energy density (ethanol).
This basic requirement leads to a number of secondary issues that collectively present an immense engineering challenge that has not been solved heretofore.
The issues associated with converting cellulosic biomass into fuel blends in an energy- and cost-efficient manner using digestion are not only complex, but they are entirely different than those that are encountered in the digestion processes commonly used in the paper and pulpwood industry.
Production of greater quantities of soluble carbohydrates for use in fuel blends and other materials via routine modification of paper and pulpwood digestion processes is not feasible for a number of reasons.
Simply running the digestion processes of the paper and pulpwood industry for a longer period of time to produce more soluble carbohydrates is undesirable from a throughput standpoint.
Use of digestion promoters such as strong alkalis, strong acids, or sulfites to accelerate the digestion rate can increase process costs and complexity due to post-processing separation steps and the possible need to protect downstream components from these agents.
Accelerating the digestion rate by increasing the digestion temperature can actually reduce yields due to thermal degradation of soluble carbohydrates that can occur at elevated digestion temperatures.
Use of higher digestion temperatures can also be undesirable from an energy efficiency standpoint.
Any of these difficulties can defeat the economic viability of fuel blends derived from cellulosic biomass.
Another issue associated with the processing of cellulosic biomass into fuel blends is created by the need for high conversion percentages of a cellulosic biomass charge into soluble carbohydrates.
Furthermore, although small in size, cellulosic biomass fines may represent a non-trivial fraction of the cellulosic biomass charge, and if they are not further converted into soluble carbohydrates, the ability to attain a satisfactory conversion percentage may be impacted.
In addition to the desired carbohydrates, other materials may be present within cellulosic biomass that can be especially problematic to deal with in an energy- and cost-efficient manner.
If not removed, these catalyst poisons can impact the catalytic reduction reaction(s) used to stabilize soluble carbohydrates, thereby resulting in process downtime for catalyst regeneration and / or replacement and reducing the overall energy efficiency when restarting the process.
On the other hand, in-process removal of these catalyst poisons can also impact the energy efficiency of the biomass conversion process, since the ion-exchange processes typically needed to affect their removal are usually conducted at temperatures below those at which soluble carbohydrates are produced by digestion, thereby introducing heat exchange operations that add to design complexity and may increase operational costs.
As evidenced by the foregoing, the efficient conversion of cellulosic biomass into fuel blends is a complex problem that presents immense engineering challenges.

Method used

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  • Biomass conversion systems providing integrated stabilization of a hydrolysate using a slurry catalyst following biomass pretreatment and methods for use thereof
  • Biomass conversion systems providing integrated stabilization of a hydrolysate using a slurry catalyst following biomass pretreatment and methods for use thereof
  • Biomass conversion systems providing integrated stabilization of a hydrolysate using a slurry catalyst following biomass pretreatment and methods for use thereof

Examples

Experimental program
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Effect test

example 1

[0160]Paste formation at high loadings of cellulosic biomass solids. 2.08 grams of finely ground pine wood sawdust containing 11.3% moisture was added to 25.5 grams of deionized water in a graduated cylinder. After mixing and allowing the wood to equilibrate, 10.4 grams of water was removed by syringe from the top of the wood bed. The cylinder was then tilted to decant additional water, but only one gram of additional water was removed, yielding a final water to dry solids ratio of 8.3:1. 0.1 grams of a slurry catalyst having a particle size of 1-25 microns was added, and the cylinder was mixed by inverting several times. Virtually no mixing of the slurry catalyst with the wood was observed due to paste formation by the finely divided wood.

example 2

[0161]Role of biomass particulate size on digestion rate. Parallel Parr 5000 reactors were loaded with 20.0 grams of 50% 2-propanol in deionized water containing 0.05 grams of sodium carbonate. 2.70 grams of soft wood pine chips containing 39% moisture was added to each reactor. In the first reactor, a single 1 inch×1 inch×3 mm wood chip was added. In the second reactor, the pine wood was hand clipped to several ¼ inch×¼ inch×3 mm mini chips. In the third reactor, the pine wood was ground in a coffee grinder to a nominal 3 mm maximum size.

[0162]All three reactors were pressurized to 51 bar with H2 and heated to 190° C. for one hour before ramping to 240° C. to complete a 5 hour cycle. The reactor contents were filtered by Whatman GF / F filter paper, and the paper with solids was dried in a vacuum oven overnight at 90° C. 78% by weight of wood from the first reactor dissolved, and the smaller wood chips in the other two reactors gave 72% by weight dissolution, on a water-free basis. I...

example 3

[0163]Digestion of cellulosic biomass in the presence of a bottom-loaded slurry catalyst. The lower 2.25-inch zone of a 12.5 inch×0.5-inch O.D. (0.402-inch I.D) digester tube was packed with ⅛-inch ceramic spheres (Denstone), followed by 0.7-inches of 14×40 mesh filter sand. On the sand was placed 0.604 grams of sulfided cobalt molybdate catalyst (DC2534, Criterion Catalyst & Technologies L.P) containing 1-10% cobalt oxide and molybdenum trioxide (up to 30 wt %) on alumina crushed to a particle size of less than 100 μm. The catalyst was previously sulfided as described in United States Patent Application publication 20100236988. The tube was then packed with 4.00 grams of southern pine wood chips having a nominal dimension of 3 mm×5 mm×5 mm, thereby forming an 8.7 inch chip bed.

[0164]The digestion unit was filled from the bottom with 50% 2-propanol / deionized water, buffered with 0.3 wt % sodium carbonate. Addition of the digestion solvent was continued until void spaces in the chip ...

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Abstract

Digestion of cellulosic biomass solids to form a hydrolysate may be conducted with integrated catalytic reduction during digestion to transform soluble carbohydrates in the hydrolysate into a more stable reaction product. Such integrated catalytic reduction may be conducted using a slurry catalyst. Biomass conversion systems for performing integrated catalytic reduction can comprise: a hydrothermal digestion unit that contains a slurry catalyst capable of activating molecular hydrogen; an optional hydrogen feed line that is operatively connected to the hydrothermal digestion unit; a fluid circulation loop comprising the hydrothermal digestion unit and a catalytic reduction reactor unit, the catalytic reduction reactor unit also containing the slurry catalyst; a pretreatment digestion unit that is not part of the fluid circulation loop and does not contain the slurry catalyst; and a solids transport mechanism operatively connecting the pretreatment digestion unit to the hydrothermal digestion unit.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This present application claims the benefit of U.S. Patent Application No. 61 / 665,668, filed Jun. 28, 2012, the entire disclosure of which is hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present disclosure generally relates to the processing of cellulosic biomass solids using digestion to produce a hydrolysate, and, more specifically, to biomass conversion systems and methods for use thereof that employ cellulosic biomass pulp in producing a hydrolysate comprising soluble carbohydrates that can be further stabilized during digestion through use of a slurry catalyst.BACKGROUND OF THE INVENTION[0003]A number of substances of commercial significance may be produced from natural sources, particularly biomass. Cellulosic biomass may be particularly advantageous in this regard due to the versatility of the abundant carbohydrates found therein in various forms. As used herein, the term “cellulosic biomass” refers to a living o...

Claims

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Application Information

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IPC IPC(8): C10G1/00
CPCC10G1/002C10G1/006C10G1/065C10G1/08C10G1/083C10G3/42C10G3/50C10G3/56C10G3/62C10G2300/1014Y02T50/678Y02P30/20Y02E50/30C10G3/00C10G2300/1011C10L1/04C10L2200/0469C10L2290/06C10L2290/10C10L2290/12
InventorPOWELL, JOSEPH BROUN
OwnerSHELL OIL CO