dens if ication

8/8/2019 Dens if Ication

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Densification of Biomass Feedstocks

Alan Doering, Agricultural Utilization Research Institute

Fueling the Future:

The Role of Woody and Agriculture Biomass for Energy Workshop

March 19, 2009

Morris

www.extension.umn.edu/agroforestry

Sponsored by:

University of Minnesota Extension, WesMin RC&D; Minnesota Department of

Natural Resources


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Densification of BiomassFeedstocks

Fueling the Future

Morris, MNMarch 19, 2009

Alan DoeringAgricultural Utilization Research Institute


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Goal

p

g

m


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Solid Fuel Focus Areas

Benefits

Market Potential

Densification Equipment Requirements

Fuel Characteristics

Pellet Quality Economics of Pellet Production
http://images.google.com/imgres?imgurl=http://www.comenalt.eu/prodotti/Light%2520pellets%5B1%5D.jpg&imgrefurl=http://www.comenalt.eu/prodotti/prodotti_eng.htm&h=520&w=650&sz=78&hl=en&start=20&um=1&usg=__lZPm3MQBC4-5I2tc0HRx_7sqens=&tbnid=npraxk0MVqte-M:&tbnh=110&tbnw=137&prev=/images?q=pellet&ndsp=20&um=1&hl=en&rls=SUNA,SUNA:2006-14,SUNA:en&sa=N


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Market Potential

Biomass Combined Heat & Power

BiomassMethanol

Biomass Ethanol (Cellulosic)

BiomassMethane

Biomass Pellet Fuels

Biomass Co-Firing


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Market Potentials

Pellet Fuel

Wood pellet stove/boiler

Corn stove/boiler

Multi-fuel stove/boiler

Outdoor furnace boiler
http://images.google.com/imgres?imgurl=http://www.lennoxhearthproducts.com/res/images/news/W_Advantage_Optima.jpg&imgrefurl=http://www.lennoxhearthproducts.com/news/view_bulletin.asp?bid=194&h=377&w=350&sz=29&hl=en&start=15&um=1&usg=__bwUZcORydhNhTlbujNdWHepl2IA=&tbnid=Eb_TO-1zFkM4tM:&tbnh=122&tbnw=113&prev=/images?q=Pellet+stoves&um=1&hl=en&rls=SUNA,SUNA:2006-14,SUNA:en&sa=N


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Market Potential

CONCERNS:

Liability

Proper fuel for stove/furnace Ignition

Ash handling/storage

Emissions


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Why Biomass Densification?

Improved transportation

More efficient storage

Bales vs. loaves

Reduced biomass losses

Moisture reduction

Improvements in processingequipment
http://images.google.com/imgres?imgurl=http://farm2.static.flickr.com/1214/890964660_055edf5cf0.jpg&imgrefurl=http://thepioneerwoman.com/2007/07/ford_power_girl.html&usg=__C5UMLN7J1qipNm63wFf01MfC9DE=&h=332&w=500&sz=116&hl=en&start=73&tbnid=GnD5nB3qM_rM_M:&tbnh=86&tbnw=130&prev=/images?q=semi+%2B+hay+hauling&start=60&gbv=2&ndsp=20&hl=en&sa=N


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Forms of Densification

Goal: To increase mass per unit ofvolume

- Grinding/particlereduction

- Compression

- Densification


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Equipment Requirements

Focus on particle size

Grinding capabilities

Industrial grinders

Hammer mills

Photos: Warren & Baerg Mfg.


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Processing Effect on Density

Effect of Grinding on Density Corn Stover:

Pre-grind on tub grinder (maximum 6 inch fiber lengths) 2.25 pounds/cubic foot

3/8 hole screen hammer mill grind 6.25 pounds/cubicfoot

Ryegrass: 38X18X16 bale 10.5 pounds/cubic foot

tub grinder (maximum 6 inch fiber lengths) 2.0

pounds/cubic foot 3/8 hole screen hammer mill grind 6.0 pounds/cubic foot

5/32 hole screen hammer mill grind 7.5 pounds/cubic foot

pellet using a 9:1 L/D pellet die 36.6 pounds/cubic foot


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Pellet Mills

- Ring die - Flat die


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Pellet Dies

- Ring die - Flat die


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Pellet Dies

Compression Ratios (L/D ratio)

Diameter

Metals

Steel

Chrome

Alloy Abrasion resistant

Feed

Channel

Ring-die

PelletsKnife

Roll


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Conditioning Capabilities

Most valuable resource

Steam vs. Water


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Sample Pellets &Characteristics

1


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Briquetting

1

AURI / University of Minnesota


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Pellet / BriquettingCharacteristics

1



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Pellet / BriquettingCharacteristics

1Form Product

Bulk Density

lbs/ft3Durability

%

PelletsCorn Stover 34 - 38 94 - 96

Switchgrass 33 - 36 73 - 87

BriquettesCorn Stover 26 - 30 67 - 90

Switchgrass 22 - 33 40 - 70



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Energy Content

Residual oil issues

Ash

Sulfur

Chlorides

Particulate Combustion Characteristics


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Pellet Quality Density

40 pound per cubic foot

Dimension Length 1 max X or

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Fines


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Pellet Quality

Pellet Durability PDI tumble tester Force gauge

Variables Fiber source Particle size Conditioning Feed rate

Die speed Die specifications

Glass transition of material (50 to 13oC)(Kaliyan and Morey, 2006a)


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Economics of PelletProduction

Material cost

Collection/transportation cost

Grinding/processing

Pelleting/cooling

Storage/bagging

Personnel/equipment

Fluctuating pellet fuel market

Debt service


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Estimated pellet plant production cost/ton:

Assumption: corn stover cost $61/ton

2 ton/hr - $101.45/ton

4 ton/hr - $180.58/ton

8 ton/hr - $147.84/ton

Source: Feasibility Study Guide for an AgriculturalBiomass Pellet Company;www.auri.org
http://www.auri.org/http://www.auri.org/


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Fixed cost: $3 - $20 per ton based on throughput

Variable cost: $26.68 per ton

Raw Material cost: $46 per ton at 12% moisture

(including transportation into plant)

Cost per ton densified: $75.68 - $92.68 per ton

Model based on 3.3- 8 ton/hr switchgrass pelleting (King 1999)

*cost do not reflect mgmt., sales, billing, or final delivery


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Drying Cost

Typically 1,400 2,000 Btu required perpound of moisture removed

63% moisture to 13% moisture = 50%

1,000 lbs water X 1,600 Btu= 1,600,000Btu

1.6 MMBtu X $9.00/MMBtu = $14.40

$28.80 / 2,000 pounds @13% moisture


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Pelleting Research

Pellet Mill Efficiencies

Economics of Pellet Production

Pellet Fuel Characterization

Pellet Quality

Combustion Characteristics


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Thank You!

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