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Beneficiation of Chipped and Ground Woody Biomass
Jim Dooley
This presentation is based upon research and development that was supported in-part by the U.S. Department of Agriculture – NIFA - Small Business Innovation
Research Program Contract No. 2009-33610-01114
Cleaning “dirty” biomass to produce quality feedstocks
Agenda• Forest Concepts – Supply Chain R&D• Characterization of Low-Grade Woody Biomass• Pathways to Achieve User Specifications• Results and Discussion• Final Thoughts
Who we are Started in 1995 to create new uses for roundwood• ELWd® engineered large woody debris habitat (1998)• FlowCheck™ engineered log erosion barriers (2000)
– USFS R4, Boise NF
• Transportable Roundwood Processing System (2002)– National Fire Plan, USFS R6, Mason Conservation District
• WoodStraw ® erosion control material (2005)– USDA/NIFA, USFS-RMRS, BLM
• Woody Biomass and Brush Baler (2008)– Street legal baler to replace small chippers
• Beneficiation of Chipped and Shredded Woody Biomass• Precision Cellulosic Biofuel Feedstocks (DOE funded)
Biomass Supply Chain & Forest Concepts
CollectionAggregationBale Transport Storage Pre-processing Conversion
Energy and
Payload
Beneficiation
Pre-Processing
Low Energy Comminution
Precision Particles
Woody Biomass Baling
Hog Fuel
Managed Drying and
Bale Handling
Bale Optimized for Horizontal
Grinders
Managed Drying and
Bale Handling
Biomass Feedstock Quality Matters
• Ash content is a major issue for pellet fuel feedstocks• Soluble minerals (e.g. alkanes, iron oxide, calcium
carbonate, sodium, potassium, …) greatly reduce yield of biofuels due to catalytic reactions
• Particle shape, size, and surface-to-volume ratios affect reaction kinetics, drying rates, materials handling, …
• Quality and value can be improved by:– Anatomical fractionation (bark, leaves, …)– Cleaning to remove soil, gravel, metal, grit, …– Washing to reduce extractives– Size sorting– Comminution methods and equipment
The problem with Hog Fuel• Dirt and grit• Bark• Fines• Overs
6/20/2012 7
Cumulative Material Composition
Bark11%
Leaves2%
Fines10%
Debris0%
Grit22%
Wood + (Wood Fraction)
6%
Clean Wood48%
WoodFiber54%
Wood + (Bark Fraction)
1%
Clean Wood
Wood + (Wood Fraction)Wood + (Bark Fraction)
Bark
Leaves
Fines
Debris
Grit
Distribution by Size & Class
0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
1 1/2 1 1/2 #4 #8 #16 Pan
Sieve Size (Containing the Material)
% o
f Tot
al M
ass
Washable Grit
Debris
Fines
Leaves
Bark
W+
CW
Cumulative Catagorized Materials
100 million tons per year available
The OPPORTUNITY with Hog Fuel•• 50% wood50% wood•• Low costLow cost•• AbundantAbundant
6/20/2012 8
Cumulative Material Composition
Bark11%
Leaves2%
Fines10%
Debris0%
Grit22%
Wood + (Wood Fraction)
6%
Clean Wood48%
WoodFiber54%
Wood + (Bark Fraction)
1%
Clean Wood
Wood + (Wood Fraction)Wood + (Bark Fraction)
Bark
Leaves
Fines
Debris
Grit
Distribution by Size & Class
0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
1 1/2 1 1/2 #4 #8 #16 Pan
Sieve Size (Containing the Material)
% o
f Tot
al M
ass
Washable Grit
Debris
Fines
Leaves
Bark
W+
CW
Cumulative Catagorized Materials50 million tons of wood fiberIF you can separate it from the rest
The problem with Urban Chips• Dirt and grit• Bark & Leaves• Fines
6/20/2012 9
30 million tons per year available
Northwest Tree Service Chipper Material Composition
Wood + (Bark Fraction)
3%
Bark11%
Leaves10%
Fines21%
Debris0%
Grit10%
WoodFiber45%
Wood + (Wood Fraction)
11%
Clean Wood34%
Clean Wood
Wood + (Wood Fraction)Wood + (Bark Fraction)
BarkLeaves
FinesDebrisGrit
Distribution by Size & Class
0.00%
5.00%
10.00%
15.00%
20.00%
25.00%
30.00%
1 1/2 1 1/2 #4 #8 #16 Pan
Sieve Size (Containing the Material)
% o
f Tot
al M
ass
Washable Grit
Debris
Fines
Leaves
Bark
W+
CW
Northwest - Tree Service - Chipper
Woody Biomass BeneficiationUSDA SBIR Objective:
Increase the supply of wood fiber to reduce conflicts and competition for traditional mill residuals – This was 3 years before BCAP!
Develop technologies to reprocess hog fuel and urban chips into fractions suitable to replace traditional mill residuals– Reduce bark content to 1, 3, or 6 % targets– Deliver clean streams of wood and bark that meet
industry sector standards for ash and grit content
Beneficiation Operations
• Screening – Overs, unders, fines, soil
• Mechanical Beating – Break up non-wood
– Wet or dry• Rinsing – sand, silt, clay, fine organic
• Air Separation - rocks
• Flotation Separation – rocks and clays
• Dewatering or drying• Specific gravity separation – gravel, sand
Ash Content by Sieve Fraction for Land Clearing Woody Biomass
Sample: 2011.07.12.001
Sieve IDOpening (mm)
Ash Content
3 75.0 0.5%1 1/2 37.5 0.56%1 25.0 1.07%1/2 12.5 1.21%1/4 6.3 1.86%1/8 3.2 14.21%
No. 16 0.7 20.82%Pan 40.11%
Note: Clean wood is ~ 0.3% ash
Ash Content 12.3 %
Pile
Dry Flail
Floatation Tank
Initial Screen
66 % Wood13 % Bark21 % Other12.3 % Ash
80 % Wood13 % Bark7 % Other2.1 % Ash
Wet Flail
Final Screen
67 % Wood15 % Bark18 % Other1.4 % Ash
77 % Wood11 % Bark13 % Other1.1 % Ash 79% Wood
18 % Bark3 % Other0.6 % Ash
100%
67%
60%
61%
Mass
57% Note: This experiment sought to minimize ash while maximizing total biomass retained. Thus, the bark content was higher than we wanted. Removing more bark would substantially reduce the mass yield of clean biomass.
SBIR Beneficiation Validation Test Ground Land Clearing Debris - Seattle
Raw Material66 % Wood13 % Bark12.3 % Ash
After Wet Flail77 % Wood11 % Bark1.1 % Ash
Ground Land Clearing DebrisSample: 2011.07.12.001
SBIR Beneficiation Validation Test Urban Arborist Chips – Auburn, WA
Pile
Dry Flail
Floatation Tank
Initial Screen
26 % Wood22 % Bark52 % Other3.2 % Ash
48 % Wood20 % Bark32 % Other2.6 % Ash
Wet Flail
Final Screen
65 % Wood22 % Bark13 % Other2.6 % Ash
59 % Wood23 % Bark18 % Other2.4 % Ash
100%
43%
27%
34%
Mass
na Note: This experiment sought to minimize ash while maximizing total biomass retained. Thus, the bark content was higher than we wanted. Removing more bark would substantially reduce the mass yield of clean biomass.
Conclusions from Validation Tests
• Land Clearing Debris– Screening alone can often get the ash content below 3%– Dry or wet flail processing can further reduce ash to less than 1.5%– Bark content was not appreciably reduced – More work to be done!– Approx. 60% of mass could be redirected to fuel pellets or furnish
• Arborist Ponderosa Pine Chips– Screening and dry flail increased wood content from 26% to 65%– More than 65% of mass was removed by processing– Total ash remained approx. 2.5% throughout testing– This sample would be uneconomical to upgrade
Market Implications
• Reprocessing ground forest residuals and other woody biomass can contribute substantial new sources of fiber to select existing and new uses– Composite panel core stock– Densified solid biofuels (export pellets)– Advanced biofuel feedstocks– Polymer composite products
Final Thoughts
• Forest Concepts’ demonstration scale portable system is available for use – 1 bdt per hour
• Forest Concepts biomass lab is open!– Particle size and shape– Anatomical and debris content analysis– Ash content– Bulk density– Flowability
• Our technical team will consult with engineering providers, plant operators, and biomass suppliers to improve feedstocks
Thank You !Jim Dooley
Forest Concepts3320 West Valley Hwy. N. D110
Auburn, WA 98001
p.253.333.9663 / [email protected] / www.forestconcepts.com
Development was supported in-part by the NIFA Small Business Innovation Research program of the U.S. Department of Agriculture, grant numbers 2008-33610-18880 and 2009-33610-101114.