www.inl.gov Drying of Wood Chips Expanding the Function of Woody Feedstock Supply Systems Christopher T. Wright, Ph.D. Manager, Biofuels and Renewable Energy Department INL/CON-12-25701 2012 Small Wood Conference Flagstaff, Arizona May 1-3, 2012
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ww
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l.govDrying of Wood Chips
Expanding the Function of Woody Feedstock Supply Systems
Christopher T. Wright, Ph.D.Manager, Biofuels and Renewable Energy Department
INL/CON-12-257012012 Small Wood Conference
Flagstaff, ArizonaMay 1-3, 2012
INL Agriculture and Biomass History
• INL has over 20 years experience in agricultural R&D including– Precision agriculture– Soil sustainability and agronomics– Autonomous control and guidance systems
• INL’s work with DOE’s Biomass Program started in 2001
• INL is the lead laboratory for biomass feedstock supply logistics RD&D and strategic analysis
• National laboratory partners– Argonne National Laboratory (ANL)– Oak Ridge National Laboratory (ORNL)– Pacific Northwest National Laboratory (PNNL)– National Renewable Energy Laboratory (NREL)– Sandia National Laboratory– Lawrence Berkeley National Laboratory
PNNL
NRELORNL
ANLINL
SNL
LBNL
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Federal Renewable Fuels Policy
President Bush 2006 State of the Union
•America is addicted to oil….The best way tobreak this addiction is through technology.We will … fund … cutting-edge methods ofproducing ethanol, not just from corn butfrom wood chips and stalks or switch grass.Our goal is to make this new kind of ethanolpractical and competitive within six years.
President Bush 2007 State of the Union
•Let us … reduce gasoline usage in the United States by 20 percent in the next 10 years. …To reach this goal, we must increase the supply of alternative fuels, by setting a mandatory fuels standard to require 35 billion gallons of renewable and alternative fuels in 2017….
These two statements have lead to federal energy legislation that has not been changed since.
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INL Bioenergy Program Guiding Documents
www.inl.gov/bioenergy4INL/CON-12-25701
INL Vision:Advanced Commodity-Scale Supply System
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Commodity-Scale Supply System Attributes
• Manages diversity and density early in the system to optimize all downstream costs
• Supports both local feedstock utilization and national-scale biomass feedstock exchange
• Helps bioenergy products compete with the fossil energy commodities they are replacing
Commodity Product Attributes
Commodity Market Attributes
Homogeneity of type, variety, quality, and end-use characteristics; adaptable to many contexts
Meets component-specific requirements of end user
Standardized material formats are storable, durable, and compatible with existing high-volume solid and liquid supply handling systems and infrastructures
Large quantity of product and large number of buyers and sellers always ready to buy or sell
Feedstock quality is assured through industry-recognized standards
Product-oriented: development focuses on maximizing output of products
Market systems secure supply and demand in a sustainable way
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Resource Conversion
Diversity Specification
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Locally Produced, Regionally Distributed, Nationally Accessible
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2012 Woody Supply System Design
Advanced Woody Supply Elements
• The impact of moisture requires implementing advanced systems
• Moisture introduces many challenges including
– Increased material instability– Material losses– Transportation and handling
costs– Decreased thermal
conversion efficiency
• Moisture is reduced in four places in the Conventional design
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Biomass Logistics Model (BLM)
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• The BLM initially determines model parameter sensitivity, uncertainty, and influence
• Each parameter is then ranked according to
• Key parameters identified• Transportation distance• Moisture content• Chipper, feller, skidder
utilization efficiency• Labor
• Research performed toaddress primary challenges
Dryer Usage
InfluenceySensitivitxyUncertaintRank =
Not included since it overwhelms the graph
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Example of Model Ranking Sensitivity on Cost
Monte Carlo analysis showing cost sensitivity for in-plant handling based on model parameter ranking and ranges in experimental data
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Total woody supply system cost sensitivity for the 2007 DOE base case scenario
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Feedstock Process Demonstration Unit• The Feedstock Process Demonstration Unit (PDU) is a modular,
reconfigurable, and deployable biomassfeedstock preprocessing system
• Design allows technologies and feedstocks to be tested in an industrial-scale system for performance and process improvement
• The baseline configuration utilizes existing technologies, allows equipment to be swapped, or operated independently
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Pneumatic Drying During Chipping
“PTS” refers to the pneumatic transfer systems used.
• Incorporating pneumatics into chipping– Reduced chip moisture content– Increased chipper efficiency– Lowered ash content in whole tree
chipped material
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Residence Drying System
• Low temperature residence drying can use excess heat from other processes– Temperature range is ambient to ~180°C
– Primary vessel holds 200 ft3 of material
– Flow rate is dependent on initial moisture and the allowable residence time
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Residence Drying – Water Removal Rate Model
• The model calculates material discharge rate and residence time for a known inlet moisture and target outlet moisture.
• Steady State Predicted Water Removal = 486 lbs
• Data Based Predicted Water Removal = 436 lbs
• Measured Water Removal = 451 lbs
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InletTemp Airflow
OutletAir Temp
OutletAir RH
WaterRemoved
Heater Settings Deg F ACFM Deg F % lbs/minSmall Heater on Low 118.8 2006 67.9 88.5 1.06Small Heater on Low 152.2 1201 71.2 89.1 0.73Small Heater on High 144.5 2010 75.0 89.0 1.59Small Heater on High 194.7 1198 81.7 90.2 1.24Large Heater on Low 227.1 1968 86.8 91.0 2.70Large Heater on Low 361.8 1200 99.5 89.8 2.54Large Heater on High 289.7 1988 97.2 89.2 3.74Large Heater on High 359.5 1524 102.2 88.8 3.34
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Residence DryerWater Removal Rate [lbs/min]
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Inlet Air Temperature [F]
Residence DryerWater Removal Rate [lbs/min]
1200 ACFM 2000 ACFM 1500 ACFM
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Required Residence Time & Resulting Discharge Rates(50% Moisture Inlet ‐ 10% Outlet Moisture)
Required Residence Time
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Resulting Discharge [lbs/hr]
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Water Removal Rage [lbs/hr]
Required Residence Time & Resulting Discharge Rates(50% Moisture Inlet ‐ 10% Outlet Moisture)
Required Residence Time
Resulting Discharge Rate
Beyond Drying to Thermal Treatment
• Thermal treatment through non-reactive and reactive methods including– deep drying 140 to 200°C– torrefying 200 to 300°
• INL system has a continuous capacity of ~100 lb/hr– Flow can be co-current or
counter-current
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• Tumuluru, J.S., R.D. Boardman, and C.T. Wright. 2012. Response Surface Analysis of Elemental Composition and Energy Properties of Corn Stover during Torrefaction. Journal of Biobased Materials and Bioenergy 2012, Vol. 6, No. 1.
• Tumuluru, J.S., S. Sokhansanj, C.T. Wright, and T. Kremer. 2011. Analysis of Volatiles and Other Products from Biomass Torrefaction Process. Gas Chromatography/Book 3, Edited by Mustafa Ali Mohd, Intech Publishers, ISBN 979-953-307-737-5.
• Tumuluru, J.S., S. Sokhansanj, J.R. Hess, C.T. Wright, and R.D. Boardman. 2011. A Review on Biomass Torrefaction Process and Product Properties for Energy Applications. Industrial Biotechnology, 7 (5): 384-401.
Densification
• Both solid and liquid densification provide logistics benefits and may improve conversion
– Need to balance energy penalty and performance gains
– Need data on yield and properties of densified feedstocks
Densification provides value to vertically integrated systems
under development today,including moisture removal
Pellet Mill Briquette press Screw press
• Tumuluru, J.S., C.T. Wright, J.R. Hess, and R.D. Boardman. 2011. A review of biomass densification systems to develop uniform feedstock commodities for bioenergy application. Biofules, Bioproducts, and Biorefining – Biofpr. Accepted July 1, 2001.
Tablet pressRoller press CuberINL/CON-12-25701 16
AddressingBarriers to Enable a National-Scale Industry
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Bioenergy Depends on Feedstock
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Thank-You
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I gratefully acknowledge the support of the U.S. DOE Energy Efficiency and Renewable Energy Office of the Biomass Program.
Idaho National Laboratory’s R&D Support Services also made valuable contributions in the preparation of this presentation, especially the Biofuels and Renewable Energy Departments R&D Specialist Leslie Ovard for her content research and organization.
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