College of Engineering Colle College ge of of Enginee Engineering ring Engineering a Non-Petroleum Binder for Use in Flexible Pavements R. Christopher Williams Mohamed Abdel Raouf Discovery with Purpose www.engineering.iastate.edu
College of Engineering Presentation Outline • Production of bio-oils and characteristics • Experimental plan and upgrading of bio-oil • Characteristics of bio asphalt • Environmental Opportunities • Summary/Conclusions • Ongoing and next steps in research Discovery with Purpose www.engineering.iastate.edu
College of Engineering Impetus for Research • Developing bio-economy • Link between bio-economy and transportation infrastructure • Renewable sources of materials • Economic opportunity Discovery with Purpose www.engineering.iastate.edu
College of Engineering Fast Pyrolysis Discovery with Purpose www.engineering.iastate.edu
College of Engineering Fast pyrolysis - rapid thermal decomposition of organic compounds in the absence of oxygen to produce gas, char, and liquids • Liquid yields as high as 78% are possible for relatively short residence times (0.5 - 2 s), moderate temperatures (400-600 o C), and rapid quenching at the end of the process Molten (Observed at very M + : Catalyzed by Alkaline Cations Biomass high heating rates) H + : Catalyzed by Acids T ~ 430 o C TM + : Catalyzed by Zero Valent Transition Metals (dT/dt) →∞ Thermo- Aerosols H + mechanical Source: Raedlin (1999) Biomass High MW Oligomers Ejection Species H + M + CO + H 2 Monomers/ M + Reforming Isomers TM + Vaporization Synthesis Gas Gases/Vapors Low Mol.Wt Species Ring-opened Chains Volatile Products Discovery with Purpose www.engineering.iastate.edu
College of Engineering Bio-oil Biochar Gas Unaccounted 2% 12% 18% 30% 37% 17% 56% 69% 26% 33% Corn stover (0.5-1.0mm) Red oak (0.75 mm) Corn fiber (1.0 mm) 10 run average, different conditions 6 run average, different conditions 2 run average, same conditions s bio-oil = 6.09%; s char = 8.27% s bio-oil = 2.21%; s char = 1.89% s bio-oil = 1.33%; s char = 0.148% *Auger pyrolyzer, ISU (2008) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Efficiency and cost of bio-oil production • Energy efficiency • Conversion to 75 wt-% bio-oil translates to energy efficiency of 70% • If carbon used for energy source (process heat or slurried with liquid) then efficiency approaches 94% • Cost • $17-$30/bbl (assuming feedstock cost of $50/ton) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Bio-Oil • Advantages include: • Liquid fuel • Decoupled conversion processes • Easier to transport than biomass or syngas • Disadvantages • High oxygen and water content makes bio-oil inferior to petroleum-derived fuels • Phase-separation and polymerization and corrosiveness make long-term storage difficult Discovery with Purpose www.engineering.iastate.edu
College of Engineering Recovery of Bio-oil as Fractions Pyrolyzed corn fiber from wet milling Fraction Fraction Fraction Fraction 1 2 3 4 Yield (wt-% of biomass) 8.0% 6.0% 29.2% 21.3% Moisture 1.54% 6.43% 5.63% 74.94% Major chemicals levoglucosan phenolics lignin oligomers acids Discovery with Purpose www.engineering.iastate.edu
College of Engineering Characteristics of Bio-oil Fractions Property Cond. 1 Cond. 2 Cond. 3 Cond. 4 ESP Fraction of total oil (wt%) 6 22 37 15 20 pH - 3.5 2.7 2.5 3.3 Viscosity @40oC (cSt) Solid 149 2.2 2.6 543 Lignin Content (wt%) High 32 5.0 2.6 50 Water Content (wt%) Low 9.3 46 46 3.3 C/H/O Molar Ratio 1/1.2/0.5 1/1.6/0.6 1/2.5/2 1/2.5/1.5 1/1.5/0.5 Discovery with Purpose www.engineering.iastate.edu
College of Engineering Products Generated from Bio-Oil • Biomass pyrolyzed to bio-oil • Bio-oil fractions converted to renewable fuel, asphalt, and other products Biomass Pyrolyzer Sugars Phenols Acids Fuel Asphalt Co-Products Discovery with Purpose www.engineering.iastate.edu
College of Engineering Experimental Plan Blend # Binder Type Polymer Modifier Type Blending Percentage AAM Bitumen None None AAD Blend 1 Control Blend 2 P1 2 Blend 3 P1 4 Blend 4 Oakwood Bio-oil P2 2 Blend 5 P2 4 Blend 6 P3 2 Blend 7 P3 4 Oxidized Polyethylene Polyethylene Property Polyethylene (P1) (P3) (P2) Drop Point, Mettler ( ° C) 101 108 115 Density (g/cc) 0.91 0.93 0.93 Viscosity @140 ° C (cps) 180 250 450 Bulk Density (kg/m 3 ) 563 536 508 Discovery with Purpose www.engineering.iastate.edu
College of Engineering Viscosity-Temperature Susceptibility 0.6 0.5 Log Log Viscosity (Pa·s) 0.4 0.3 0.2 Blend 1 Blend 2 Blend 3 Blend 4 Blend 5 0.1 Blend 6 Blend 7 AAM AAD 0 2.74 2.76 2.78 2.80 2.82 2.84 2.86 2.88 2.90 Log Temperature (Rankine) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Effect of Shear Rate on Viscosity 7000 AAM at 110 AAD at 110 Blend 1 at 60 6000 Blend 2 at 60 Blend 3 at 60 Blend 4 at 100 5000 Blend 5 at 100 Blend 6 at 100 Blend 7 at 100 Viscosity (cP) 4000 3000 2000 1000 0 0 20 40 60 80 100 120 Shear Rate (rpm) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Arrhenius Model for AAM 12 2 10 4 Log Viscosity (Pa.S) 10 8 20 R² = 0.9936 50 6 100 Expon. (20) 4 2 0 2.7E-04 2.8E-04 2.9E-04 3.0E-04 3.1E-04 3.2E-04 3.3E-04 3.4E-04 1/R*Temp (K) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Arrhenius Model for AAD 12 2 10 4 Log Viscosity (Pa.S) 10 8 20 50 6 100 Expon. (20) 4 R² = 0.9934 2 0 2.7E-04 2.8E-04 2.9E-04 3.0E-04 3.1E-04 3.2E-04 3.3E-04 3.4E-04 1/R*Temp (K) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Arrhenius Model for Blend 1 12 2 10 4 Log Viscosity (Pa.S) 10 8 20 50 6 100 Expon. (20) 4 R² = 0.9889 2 0 3.3E-04 3.4E-04 3.5E-04 3.6E-04 3.7E-04 3.8E-04 3.9E-04 1/R*Temp (K) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Arrhenius Model for Blend 2 40 2 35 4 Log Viscosity (Pa.S) 30 10 25 20 20 50 15 100 10 Expon. (20) 5 R² = 0.9991 0 3.3E-04 3.4E-04 3.5E-04 3.6E-04 3.7E-04 3.8E-04 3.9E-04 1/R*Temp (K) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Arrhenius Model for Blend 4 12 2 10 4 Log Viscosity (Pa.S) 10 8 20 50 6 100 Expon. (20) 4 R² = 0.9774 2 0 2.7E-04 2.8E-04 2.9E-04 3.0E-04 3.1E-04 3.2E-04 3.3E-04 3.4E-04 1/R*Temp (K) Discovery with Purpose www.engineering.iastate.edu
College of Engineering Secondary Charcoal Generation Discovery with Purpose www.engineering.iastate.edu
College of Engineering Bio-char: Soil amendment & carbon sequestration Nature, Vol. 442, 10 Aug 2006 Discovery with Purpose www.engineering.iastate.edu
College of Engineering Several studies have reported large 30000 Plant Population on 6/24/08 increases in crop yields from the use (Seeding rate 30000) Plant Population (plants/Ac) 28000 of biochar as a soil amendment. B However, most of these studies were 26000 conducted in the tropics on low AB 24000 fertility soils. Need to study how A 22000 temperate region soils will respond to biochar amendments. 20000 Control Biochar Biochar (4.4 ton/Ac) (8.2 ton/Ac) First year trials in Iowa showed a 190 Corn yield 2008 15% increase plant populations, (56 total plots) and a 4% increase in corn grain 180 Yield (bu/Ac) yield from biochar applications.* B AB 170 A *However, biochar quality is very important. The wrong type of biochar 177 bu/ac 171 bu/ac 175 bu/ac n = 12 n = 32 n = 12 can cause yield decreases! 160 Biochar Control Biochar (4.4 ton/ac) (8.2 ton/ac) Discovery with Purpose Laird et al. www.engineering.iastate.edu
College of Engineering Greenhouse gases reduced by carbon storage in agricultural soils Carbon Stored (lb/acre/yr) 2000 1800 1600 1400 1200 1000 800 600 400 200 0 Pyrolytic Char No-Till No-Till Corn Plow-Tilled Switchgrass Corn Char from pyrolyzing one-half of corn stover Discovery with Purpose www.engineering.iastate.edu
College of Engineering Summary • Bio asphalt has similar temperature sensitivity to petroleum derived asphalt. • The temperature range for the bio-oil and bitumen blends were different. • An asphalt derived from biomass has been developed that behaves like a viscoelastic material just like petroleum derived asphalt. • The bio asphalt can be produced locally • The production process sequesters greenhouse gases. Discovery with Purpose www.engineering.iastate.edu
College of Engineering Ongoing Activities • Performance grade binders have been developed • Mix performance testing • Rutting • Fatigue Cracking • Thermal Cracking • Building test pavement sections Discovery with Purpose www.engineering.iastate.edu
College of Engineering Moving Forward • Laboratory mix performance • Scale up of production facilities • Substantial capital investment • Multiple end markets for pyrolysis products • Demonstration projects • Biomass composition varies, and thus products can vary Discovery with Purpose www.engineering.iastate.edu
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