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Societal Issues. Economy Transportation fuel pricing Job creation Infrastructure funding & renewal Energy independence Climate change. Asphalt Industry Background & Challenges. Approximately 68% of GDP utilizes our transportation systems About 90% of Nation’s paved highways use asphalt
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Societal Issues • Economy • Transportation fuel pricing • Job creation • Infrastructure funding & renewal • Energy independence • Climate change
Asphalt IndustryBackground & Challenges • Approximately 68% of GDP utilizes our transportation systems • About 90% of Nation’s paved highways use asphalt • Asphalt pavements and composite pavements • Maintenance applications (patching, crack sealing, surface treatments) • Asphalt is derived from crude petroleum • Refinery modifications has removed asphalt from the market to produce more transportation fuels
Impacts of Higher Crude Oil Prices • Higher asphalt & fuel prices reduces the number of infrastructure projects • Fewer miles driven • 50 billion fewer miles from November 2007 to May 2008 • 11 billion fewer comparing March 2007 to March 2008 (4.3% decrease) • 15 billion fewer miles comparing August 2007 to August 2008 (5.6% decrease) • Decrease in highway tax revenue • Less asphalt polymers available due to reduction in tire manufacturing & reduction in butadiene production • Less money for infrastructure projects
Asphalt Industry Market Colorado • 9.0 million tons of hot mix asphalt ($540 million annually) • 450,000 liquid tons of asphalt ($320 million annually- net import to Colorado) • 68 stationary & 8 mobile hot mix asphalts plants • Industry employs about 7,500 consisting of trades people, engineers, and financial & banking specialists Nationally • 500 million tons of hot mix asphalt ($30 billion annually) • 30 million liquid tons of asphalt ($21 billion annually) • ~4,000 stationary & 500 mobile hot mix asphalt plants
Bio-economy and Transportation Link • Market share of bio-energy will become greater percentage of overall energy sector • 2007 Energy Title mandates 36 billion gallons of ethanol be sold in U.S. by 2022; 21 billion gallons of which must be produced from cellulosic feedstocks • fast pyrolysis is one of the systems that will likely be deployed to produce cellulosic biofuels • bio-oil produced from fast pyrolysis shows great promise as an asphalt material • Solutions for utilizing bio-energy co-products exist in asphalt industry
Fast Pyrolysis Rapid thermal decomposition of organic compounds in the absence of oxygen to produce gas, char, and liquids Molten Biomass T ~ 430oC (Observed at very high heating rates) M+ : Catalyzed by Alkaline Cations H+ : Catalyzed by Acids TM+ : Catalyzed by Zero Valent Transition Metals (dT/dt)→∞ Thermo- mechanical Ejection Aerosols High MW Species H+ Biomass Oligomers H+ CO + H2 M+ Monomers/ Isomers M+ Reforming TM+ Vaporization Synthesis Gas Gases/Vapors Low Mol.Wt Species Ring-opened Chains Volatile Products
Fundamental Studies with Micropyrolyzer and GC/MS ~ 500 μg Pyrolyzer He Feedstock Mass Spectrometer (MS) Capillary Separation Column Gas Chromatograph (GC)
GC/MS Analysis of Feedstock Materials Oak Wood Switch Grass Corn Stover
GC/MS Analysis of ESP Fractions Oak Wood Switch Grass Corn Stover
Fast Pyrolysis Products Biomass Pyrolyzer Sugars Phenols Acids Fuel Asphalt Co-Products • Biomass pyrolyzed to bio-oil • Bio-oil fractions converted to renewable fuel, asphalt, and other products
Fast Pyrolysis Rapid thermal decomposition of organic compounds in the absence of oxygen to produce liquids, char, and gas Small particles: 1 - 3 mm Short residence times: 0.5 - 2 s Moderate temperatures (400-500 oC) Rapid quenching at the end of the process • Typical yields • Oil: 60 - 70% • Char: 12 -15% • Gas: 13 - 25%
Bio-char: Soil amendment and carbon sequestration agent Nature, Vol. 442, 10 Aug 2006
Greenhouse gases reduced by carbon storage in agricultural soils Carbon Stored (lb/acre/yr) Char from pyrolyzing one-half of corn stover
Greenhouse Gas Emission Comparison • Bio-oil is a closed system with greenhouse gases (GHG) sequestered • Crude refinery products are about 165lbs (0.083 tons) of GHG per ton of product (asphalt) • Cement production is 0.7 tons GHG per ton of cement
Experimental Plan • Three asphalt binders • 1 local binder (1 polymer-modified, 1 neat binder) • 2 well known binders (AAD-1 & AAM-1) • Three experimental bio-oil fractions • Corn Stover • Oak Wood • Switch Grass • Each asphalt mixed with each lignin sample at 3, 6, and 9 percent by weight • Evaluate rheological properties and determine Tc and performance grade of each blend
Performance Testing 1. Blend asphalt and lignin in a high speed shear mill at 145°C for 15 minutes 3. Short-term age asphalt/lignin blends with a RTFO 2. Evaluate high-temperature rheological properties of unaged blends with a DSR 6. Evaluate inter-temperature rheological properties of PAV aged blends with a DSR 5. Long-term age asphalt/lignin blends with a PAV 4. Evaluate high-temperature rheological properties of RTFO aged blends with a DSR 8. Calculate continuous performance grade of mixtures 7. Evaluate low-temperature rheological properties of unaged blends with a BBR 9. Compare results of different asphalt/bio oil blends
Summary of Asphalt/Bio-oil Research • The addition of lignin containing co-products to asphalt binders causes a stiffening effect • Binder effects • Biomass Source of Lignin • Amount of Lignin • The stiffening effect increases the high, int., and low critical temperatures of the asphalt/lignin blends • The high temperatures are increased more than the low temperatures • Grade ranges in some combinations are increased by one grade (6ºC) and in other combinations no effects
Development of a Bio Binder • Can bio oil fractions be upgraded to produce an asphalt binder replacement? • If so, how is this accomplished? • Will the technology be turn key with existing asphalt industry production & construction processes? • What is the performance of the bio binder? • How do we specify bio binder quality?
Development of “Reaction” Curves • Understand that bio oil properties can change with heating • Assist with formulating bio binders
Dynamic Shear Rheometer Testing • Created bio binder grades of 52 and 58ºC based upon unaged samples • Mixing Temperature of 105ºC • What is the appropriate short term aging protocol? • What is the appropriate long term aging protocol?
What makes bio-oil attractive for use in asphalt industry? • Replacement of asphalt binder at a lower price • Can be used as an asphalt anti-oxidant additive to increase asphalt pavement life • Can lower asphalt plant production temperatures • Lower plant operating costs (fuel consumption) • Lower production temperatures reduces greenhouse gas production • Bio-oil is renewable
Research Questions • Specification criteria • Field handling & constructability • Field performance Full scale pilot plant under construction and anticipate field trials 2009 construction season
Benefits to United States • Economic development and job creation • Lower petroleum based product pricing by creating alternatives • Sustainable transportation inputs with lower GHG • Lower infrastructure costs- construction, pavements and maintenance activities • Petroleum independence
Acknowledgements • Iowa Department of Transportation • www.iowadot.gov/operationsresearch/default.html • Iowa Energy Center • www.energy.iastate.edu