# US 9,039,792 B2 · Methods for producing and using densified biomass products containing pretreated biomass fibers

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- Number: US 9,039,792 B2
- Document ID: US9039792B2
- Status: Granted
- Kind: B2
- Application number: 13/835,766
- Filed: 2013-03-15
- Published: 2013-10-24
- Granted: 2015-05-26
- Earliest claimed: 2009-08-24
- Assignees: Board of Trustees of Michigan State University
- Applicants: Board of Trustees of Michigan State University
- Inventors: Bruce E. Dale; Bryan Ritchie; Derek Marshall
- Web page: https://patentgrep.com/patent/US9039792B2

## CPC

- D21B 1/021: {by chemical means}
- A23K 10/37: from waste material (from hydrolysates of wood or straw A23K10/32; from molasses A23K10/33)
- C10L 5/363: {Pellets or granulates}
- C10L 5/44: on vegetable substances
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02E 50/30: Fuel from waste, e.g. synthetic alcohol or diesel
- Y02P 60/87: Re-use of by-products of food processing for fodder production
- Y10T 428/2938: Coating on discrete and individual rods, strands or filaments
- D21B: FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
- A23K: FODDER
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A process is provided comprising subjecting a quantity of plant biomass fibers to a pretreatment to cause at least a portion of lignin contained within each fiber to move to an outer surface of said fiber, wherein a quantity of pretreated tacky plant biomass fibers is produced; and densifying the quantity of pretreated tacky plant biomass fibers to produce one or more densified biomass particulates, wherein said biomass fibers are densified without using added binder.

## Claims

### Claim 1

A process comprising:
subjecting a quantity of plant biomass fibers to a pretreatment to cause at least a portion of lignin contained within each fiber to move to an outer surface of said fiber, wherein a quantity of pretreated tacky plant biomass fibers is produced; and
densifying the quantity of pretreated tacky plant biomass fibers to produce one or more densified biomass particulates, wherein said biomass fibers are densified without using added binder.

### Claim 2 (depends on 1)

The process of claim 1 wherein each of said densified biomass particulates has a substantially smooth, non-flakey outer surface.

### Claim 3 (depends on 1)

The process of claim 1 wherein the pretreatment is a sodium hydroxide pretreatment or an ammonia pretreatment.

### Claim 4 (depends on 3)

The process of claim 3 wherein the ammonia pretreatment comprises a liquid ammonia fiber expansion (AFEX) pretreatment or a gaseous AFEX pretreatment.

### Claim 5 (depends on 3)

The process of claim 3 further comprising adding water and/or steam prior to and/or during the pretreatment.

### Claim 6 (depends on 1)

The product of claim 1 wherein said biomass fibers contain a trace amount of base.

### Claim 7 (depends on 6)

The product of claim 6 wherein the trace amount of base comprises about 1% to about 2% of ammonia.

### Claim 8 (depends on 1)

The process of claim 1 wherein said biomass fibers comprise reduced lignin and/or hemicellulose levels in their interiors and increased lignin and/or hemicellulose levels on their surfaces as compared with the lignin and/or hemicellulose levels of said fibers prior to the pretreatment, wherein said surface lignin and/or hemicellulose levels provide a degree of tackiness thereon.

### Claim 9 (depends on 8)

The process of claim 8 wherein said biomass fiber interiors contain microscopic pores and a portion of the lignin and/or hemicellulose is present within the microscopic pores.

### Claim 10 (depends on 9)

The process of claim 9 wherein said biomass fibers are coated with lignin on their surfaces and at least some of said biomass fibers are also coated with hemicellulose.

### Claim 11 (depends on 1)

The process of claim 1 wherein said densified biomass particulates have an increased resistance to deformation, an increased hardness, an increased resistance to degradation, an improved shelf life, or a combination thereof, as compared with densified plant biomass particulates containing added binder.

### Claim 12 (depends on 1)

The process of claim 1 wherein said densified biomass particulates are at least 21% harder with at least 20% less variability in hardness as compared to the densified plant biomass particulates containing added binder.

### Claim 13 (depends on 1)

The process of claim 1 wherein said densified biomass particulates have a substantially rectangular shape or a substantially cylindrical shape.

### Claim 14 (depends on 1)

The process of claim 1 wherein said biomass fibers are corn stover fibers, switchgrass fibers, prairie cord grass fibers, or combinations thereof.

### Claim 15 (depends on 1)

The process of claim 1 comprising a plurality of densified biomass particulates of a given mass having a higher bulk density than baled or loose plant biomass of the same given mass.

### Claim 16 (depends on 1)

The process of claim 1 comprising a plurality of densified biomass particulates of a given number, wherein said densified biomass particulates have an increased flowability, a higher bulk density, or a combination thereof, as compared with a plurality of densified plant biomass particulates of the same given number containing added binder.

### Claim 17 (depends on 1)

The process of claim 1 wherein the pretreatment is performed in a pretreatment facility, the densification is performed in a densifying facility and the method further comprises providing said densified biomass particulates to a bioproduct production facility.

### Claim 18 (depends on 17)

The process of claim 17 wherein at least the pretreatment facility and densifying facility are co-located in a regional biomass process center.

### Claim 19 (depends on 18)

The process of claim 18 wherein said biomass fibers include corn stover and the process further comprises providing the corn stover to the RBPC Regional Biomass Processing Center.

### Claim 20 (depends on 17)

The process of claim 17 wherein the bioproduct production facility is a chemical production facility or an alcohol production facility.

### Claim 21 (depends on 17)

The process of claim 17 wherein the process further comprises converting said densified biomass particulates to one or more bioproducts in the bioproduct production facility.

### Claim 22 (depends on 21)

The process of claim 21 wherein the converting comprises fermenting said densified biomass particulates to produce a sugar-containing stream, wherein fermentation rates are improved as compared to fermentation rates achieved using non-densified plant biomass.

### Claim 23 (depends on 2)

A product produced according to the process of claim 2.

### Claim 24

A process comprising:
subjecting a quantity of plant biomass fibers to an ammonia pretreatment to cause at least a portion of lignin and/or hemicellulose contained within each fiber to move to an outer surface of said fiber to produce a quantity of pretreated tacky plant biomass fibers, wherein the ammonia pretreatment generates reduced levels of lignin and/or hemicellulose in an interior of said fiber and increased lignin and/or hemicellulose on its surface as compared with pretreatment levels of lignin and/or hemicellulose, wherein said surface lignin and/or hemicellulose has a degree of tackiness; and
densifying the quantity of pretreated tacky plant biomass fibers to produce one or more densified biomass particulates, wherein the quantity of said biomass fibers is densified without using added binder.

### Claim 25 (depends on 24)

The process of claim 24 wherein the ammonia pretreatment is a liquid ammonia fiber expansion (AFEX) pretreatment or a gaseous AFEX pretreatment.

### Claim 26 (depends on 24)

The process of claim 24 wherein the ammonia pretreatment comprises heating said biomass fibers to a temperature between about 60 and about 100° C.

### Claim 27 (depends on 24)

The process of claim 24 wherein said densification is performed without a curing step.

### Claim 28 (depends on 24)

The process of claim 24 wherein said densification comprises performing compression at a temperature less than 60° C.

### Claim 29 (depends on 24)

The process of claim 24 wherein said densification comprises increasing pressure at a rate of less than 0.034 atm/sec.

### Claim 30 (depends on 24)

The process of claim 24 wherein said densified biomass particulates have an increased gross caloric value as compared with densified biomass particulates containing untreated plant biomass fibers.

### Claim 31 (depends on 30)

The process of claim 30 wherein said densified biomass particulate burns about 4.8% more efficiently as compared with a densified biomass particulate containing untreated plant biomass fibers.

### Claim 32 (depends on 31)

The process of claim 31 wherein a given mass of a plurality of densified biomass particulates has a reduced amount of fines as compared with a plurality of densified biomass particulates of the same given mass containing untreated plant biomass fibers.

### Claim 33 (depends on 24)

The process of claim 24 wherein said densification comprises forming a plurality of densified biomass particulates of a given mass having a higher bulk density than baled or loose plant biomass of the same given mass.

### Claim 34 (depends on 33)

The process of claim 33 wherein said densified biomass particulates have a bulk density of between about 547.2 kg/m3 and about 765 kg/m3.

### Claim 35 (depends on 24)

The process of claim 24 wherein said biomass fibers comprise an agricultural crop waste, a woody energy crop, a wood waste and/or a grass crop.

### Claim 36 (depends on 24)

The process of claim 24 wherein said densification comprises compressing said densified biomass particulates through a tapering channel.

### Claim 37 (depends on 24)

The process of claim 24 further comprising adding water and/or steam prior to and/or during the ammonia pretreatment step.

### Claim 38 (depends on 24)

The process of claim 24 wherein the pretreatment and densifying steps are performed as an integrated process at a single location.

### Claim 39 (depends on 38)

The process of claim 38 wherein said single location comprises a regional processing center located within about 8 to about 16 kilometers of a biomass source.

### Claim 40 (depends on 24)

A product made according to the process of claim 24.

### Claim 41

A process comprising using one or more densified biomass particulates in a bioproduct production facility to produce a product, wherein said densified biomass particulates are each comprised of a plurality of pretreated lignin-coated plant biomass fibers containing a trace amount of base, wherein said densified biomass particulates have a substantially smooth, non-flakey outer surface and contain no added binder.

### Claim 42 (depends on 41)

The process of claim 41 wherein the bioproduct production facility is a chemical production facility or an alcohol production facility.

### Claim 43 (depends on 42)

The process of claim 42 wherein said biomass fibers are corn stover fibers, switchgrass fibers, prairie cord grass fibers, or combinations thereof.

### Claim 44 (depends on 43)

The process of claim 43 wherein said densified biomass particulates are fermented in the bioproduct production facility and fermentation rates are improved as compared to fermentation rates achieved using non-densified plant biomass.

### Claim 45 (depends on 44)

The process of claim 44 wherein the product is an agricultural biofuel.

### Claim 46 (depends on 45)

The process of claim 45 wherein the agricultural biofuel is ethanol and said biomass fibers comprise corn stover.