Engineering a Non-Petroleum Binder for Use in Flexible ...ncaupg/Activities/2010...2002/04/10  ·...

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College of Engineering

Engineering a Non-Petroleum Binder for Use

in Flexible Pavements

R. Christopher Williams

Mohamed Abdel Raouf

College of Engineering

Discovery with Purpose www.engineering.iastate.edu

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

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Impetus for Research

• Developing bio-economy

• Link between bio-economy and transportation

infrastructure

• Renewable sources of materials

• Economic opportunity

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Fast Pyrolysis

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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 oC), and rapid quenching at the end of the process

Biomass

Monomers/

Isomers

Low Mol.Wt Species

Ring-opened Chains

H+

H+

M+M+

Aerosols

High MW

Species

Gases/Vapors

Thermo-

mechanical

Ejection

Vaporization

Molten

Biomass

T ~ 430oC(dT/dt)→∞

CO + H2

Synthesis Gas

Reforming

TM+

Volatile Products

M+ : Catalyzed by Alkaline Cations

H+ : Catalyzed by Acids

TM+ : Catalyzed by Zero Valent Transition Metals

(Observed at very

high heating rates)

Oligomers Source: Raedlin (1999)

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Corn stover (0.5-1.0mm)10 run average, different conditions

sbio-oil = 6.09%; schar= 8.27%

Corn fiber (1.0 mm)2 run average, same conditions

sbio-oil = 1.33%; schar= 0.148%

26%

18%

56%

Red oak (0.75 mm)6 run average, different conditions

sbio-oil = 2.21%; schar= 1.89%

17%

12%

69%

2%

37%30%

33%

Bio-oil Biochar Gas Unaccounted

*Auger pyrolyzer, ISU (2008)

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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)

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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

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Recovery of Bio-oil as Fractions

Fraction

1

Fraction

2

Fraction

3

Fraction

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

Pyrolyzed corn fiber from wet milling

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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 Ratio1/1.2/0.5 1/1.6/0.6 1/2.5/2 1/2.5/1.5 1/1.5/0.5

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Products Generated from Bio-Oil

• Biomass pyrolyzed to bio-oil

• Bio-oil fractions converted to renewable fuel, asphalt, and other products

Pyrolyzer

Sugars Phenols Acids

Fuel Asphalt Co-Products

Biomass

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Experimental PlanBlend # Binder Type Polymer Modifier Type Blending Percentage

AAMBitumen None None

AAD

Blend 1

Oakwood Bio-oil

Control

Blend 2 P1 2

Blend 3 P1 4

Blend 4 P2 2

Blend 5 P2 4

Blend 6 P3 2

Blend 7 P3 4

PropertyPolyethylene

(P1)

Oxidized

Polyethylene

(P2)

Polyethylene

(P3)

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/m3) 563 536 508

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Viscosity-Temperature Susceptibility

0

0.1

0.2

0.3

0.4

0.5

0.6

2.74 2.76 2.78 2.80 2.82 2.84 2.86 2.88 2.90

Log L

og V

isco

sity

(P

a·s

)

Log Temperature (Rankine)

Blend 1 Blend 2 Blend 3 Blend 4 Blend 5

Blend 6 Blend 7 AAM AAD

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Effect of Shear Rate on Viscosity

0

1000

2000

3000

4000

5000

6000

7000

0 20 40 60 80 100 120

Vis

cosi

ty (

cP)

Shear Rate (rpm)

AAM at 110 AAD at 110 Blend 1 at 60

Blend 2 at 60 Blend 3 at 60 Blend 4 at 100

Blend 5 at 100 Blend 6 at 100 Blend 7 at 100

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Arrhenius Model for AAM

R² = 0.9936

0

2

4

6

8

10

12

2.7E-04 2.8E-04 2.9E-04 3.0E-04 3.1E-04 3.2E-04 3.3E-04 3.4E-04

Log V

isco

sity

(P

a.S

)

1/R*Temp (K)

2

4

10

20

50

100

Expon. (20)

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Arrhenius Model for AAD

R² = 0.9934

0

2

4

6

8

10

12

2.7E-04 2.8E-04 2.9E-04 3.0E-04 3.1E-04 3.2E-04 3.3E-04 3.4E-04

Log V

isco

sity

(P

a.S

)

1/R*Temp (K)

2

4

10

20

50

100

Expon. (20)

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Arrhenius Model for Blend 1

R² = 0.9889

0

2

4

6

8

10

12

3.3E-04 3.4E-04 3.5E-04 3.6E-04 3.7E-04 3.8E-04 3.9E-04

Log V

isco

sity

(P

a.S

)

1/R*Temp (K)

2

4

10

20

50

100

Expon. (20)

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Arrhenius Model for Blend 2

R² = 0.9991

0

5

10

15

20

25

30

35

40

3.3E-04 3.4E-04 3.5E-04 3.6E-04 3.7E-04 3.8E-04 3.9E-04

Log V

isco

sity

(P

a.S

)

1/R*Temp (K)

2

4

10

20

50

100

Expon. (20)

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Arrhenius Model for Blend 4

R² = 0.9774

0

2

4

6

8

10

12

2.7E-04 2.8E-04 2.9E-04 3.0E-04 3.1E-04 3.2E-04 3.3E-04 3.4E-04

Log V

isco

sity

(P

a.S

)

1/R*Temp (K)

2

4

10

20

50

100

Expon. (20)

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Secondary Charcoal Generation

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Nature, Vol. 442, 10 Aug 2006

Bio-char: Soil amendment & carbon sequestration

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*However, biochar quality is very important. The wrong type of biocharcan cause yield decreases!

Several studies have reported large

increases in crop yields from the use

of biochar as a soil amendment.

However, most of these studies were

conducted in the tropics on low

fertility soils. Need to study how

temperate region soils will respond

to biochar amendments. 20000

22000

24000

26000

28000

30000

Pla

nt

Po

pu

lati

on

(p

lan

ts/A

c)

Control Biochar

(4.4 ton/Ac)

Biochar

(8.2 ton/Ac)

B

AB

A

Plant Population on 6/24/08(Seeding rate 30000)

160

170

180

190

Yie

ld (

bu

/Ac

)

Control Biochar

(4.4 ton/ac)

B

Biochar

(8.2 ton/ac)

AB

A

175 bu/ac

n = 12

177 bu/ac

n = 12171 bu/ac

n = 32

Corn yield 2008 (56 total plots)

First year trials in Iowa showed a

15% increase plant populations,

and a 4% increase in corn grain

yield from biochar applications.*

Laird et al.

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Ca

rbo

n S

tore

d (

lb/a

cre

/yr)

Greenhouse gases reduced by

carbon storage in agricultural soils

0200400600800

100012001400160018002000

Pyrolytic Char No-Till Switchgrass

No-Till Corn Plow-Tilled Corn

Char from pyrolyzing one-half of corn stover

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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.

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Ongoing Activities

• Performance grade binders have been developed

• Mix performance testing

• Rutting

• Fatigue Cracking

• Thermal Cracking

• Building test pavement sections

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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

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Thanks & Acknowledgements

• Center for Sustainable Environmental Technology

• Robert Brown

• Sam Jones, Marge Rover

• Iowa Energy Center

• Iowa Department of Transportation

• Mark Dunn & Sandra Larson

• Scott Schram, John Hinrichsen & Jim Berger

• Iowa Highway Research Board

• Counties and Local Agencies

• Asphalt Paving Association of Iowa

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Thank You!

&

Questions?