Dr. Robert Brown is a foremost expert and author on biomass conversion processes with the CenUSA project and the Bioeconomy Institute at Iowa State University. In this presentation he focuses on using thermochemical processes for production of liquid biofuels. Discussion of: feedstocks, renewable fuels tegnologies, gasification and pyrolysis, products and by-products, energy efficiency, opportunities and challenges, biochar.

1. Center for Sustainable Environmental Technologies
The
Thermochemical Option
Robert C. Brown
Robert C. Brown
Center for Sustainable
Environmental Technologies
Iowa State University
Iowa State University
CenUSA Webinar
May 25, 2012

2. Center for Sustainable Environmental Technologies
What is the Perfect Energy Carrier for Transportation Fuel?
What is the Perfect Energy Carrier for Transportation Fuel?
• Liquid at ambient conditions
d b d
• Immiscible in water
• Low toxicity
• High energy density
• Cold weather operability
• Stable during long‐term storage
• Efficient production from a primary energy source

3. Center for Sustainable Environmental Technologies
Drop‐In Fuels
Drop‐In Fuels
• Fully compatible with existing fuel infrastructure
– Hydrocarbons (alkanes and aromatics)
– Possibly butanol
• Are drop in fuels
also the “perfect fuel?”
– Close enough

4. Center for Sustainable Environmental Technologies
Three Kinds of Biomass
Three Kinds of Biomass
• Lipid‐rich biomass
Lipid‐rich biomass
• Lignocellulosic biomass
• Waste biomass

5. Center for Sustainable Environmental Technologies
Lignocellulosic Feedstock
• Lignocellulose a three-
three
dimensional polymeric
composites formed by plants
as structural material
• Constituents include:
– Cellulose: main source of
glucose (C6 sugar)
– Lignin: source of xylose (C5
sugar)
g )
Glycosidic
• Simple sugars can be bonds
liberated from carbohydrate
either enzymatically or
Cellulose is a polymer of monosaccharides
thermally (glucose)

6. Center for Sustainable Environmental Technologies
Lipid Feedstocks: Nearly hydrocarbons
Lipid Feedstocks: Nearly hydrocarbons
• Triglycerides: Three fatty acids attached to glycerol
backbone found in oil seeds and microalgae
b kb f d i il d d i l
• Readily converted to pure hydrocarbons via
hydrogenation
h d ti
H2 H2 H2 H2 H2 H2 H2 H2 O
H3C C C C C C C C C C O CH2
C C C C C C C C
H2 H2 H2 H2 H2 H2 H2 H2
H2 H2 H2 H2 H2 H2 H2 H2 O
H3C C C C C C C C C C O CH
C C C C C C C C
H2 H2 H2 H2 H2 H2 H2 H2
H2 H2 H2 H2 H2 H2 H2 H2 O
H3C C C C C C C C C C O CH2
C C C C C C C C
H2 H2 H2 H2 H2 H2 H2 H2

7. Center for Sustainable Environmental Technologies
Lipids vs
Lipids vs Lignocellulose
Which Kind of Plant Should Deoxygenate Carbohydrate?
Glucose Unit Glycosidic Bonds
OH CH2OH OH CH2OH OH CH2OH OH
O O O O O O
OH OH
OH OH OH
Plant No. 2
OH OH
O O O O O O O
CH2OH OH CH2OH OH CH2OH OH CH2OH
Plant No. 1 CO2
H2O
Lipid biosynthesis
Lipid
involves biological
deoxygenation of
yg
carbohydrates, too!
CO2
Cellulose to hydrocarbons
Cellulose to hydrocarbons
involves deoxygenation of CO2
Source: Nature Medicine
carbohydrate 11, 599 – 600, 2005.

8. Center for Sustainable Environmental Technologies
Renewable Fuels Technologies
Renewable Fuels Technologies
FEEDSTOCKS TECHNOLOGY BIOFUELS
OILSEED
CROPS Transesterification
FAME
ALGAE
Pyrolysis
Gasification
AG WASTES CELLULOSIC
Catalysis
BIOMASS FUEL
HYDROCARBONS
TREES Chemical
GRASSES Catalysis
GRAINS STARCH ALCOHOLS
Biochemical
SUGAR Conversion
C i
SUGARCANE

9. Center for Sustainable Environmental Technologies
Thermochemical Biofuels
Thermochemical Biofuels
• The other cellulosic biofuels…
• Syngas to biofuels
(via gasification)
• Bi il t bi f l
Bio‐oil to biofuels
(via fast pyrolysis)
• Builds upon core competencies at
Builds upon core competencies at ½ tpd oxygen-blown gasifier at ISU’s
BioCentury Research Farm
ISU
• Gasification and pyrolysis
• Catalysis
• Novel fermentations
• Techno‐economic and life cycle
analysis
l i
1/4 tpd fast pyrolyzer at ISU’s BioCentury
Research Farm
USDA REE E S it

10. Center for Sustainable Environmental Technologies
Generalized Thermochemical Process
Generalized Thermochemical Process
Feedstock
Depolymerization/ Decomposition
Depolymerization/ Decomposition
Thermolytic
Thermolytic
Substrate
Upgrading
Biofuel

11. Center for Sustainable Environmental Technologies
Gasification
• Gasification is the thermal decomposition of organic matter
into flammable gases
g
Heating and Drying Pyrolysis Gas-Solid Reactions Gas-phase Reactions
Volatile gases: CO, CO + H2O  CO2 + H2
CO2, H2, H2O light
O,
hydrocarbons, tar CO + 3H2  CH4 + H2O
H 2O Heat
CO
2 CO ½ O2
CO2
char
2H2
Porosity increases CO
CH4
Thermal front H2O
H2
penetrates particle
Endothermic Exothermic
reactions reactions
11

12. Center for Sustainable Environmental Technologies
Two Major Gasification Options
Two Major Gasification Options
Low Temperature Gasification High Temperature Gasification
(Bubbling Fluidized Bed) (Entrained Flow Gasifier)
oxygen
Syngas biomass
Biomass
1300 °C
Ash
Fluidized Bed
Water cooled
radiation screen
Steam/
Oxygen
O
raw syngas and
molten slag

13. Center for Sustainable Environmental Technologies
Syngas
• Syngas consists mostly of CO, H2, CO2, CH4
Composition of syngas (volume percent)
Hydrogen Carbon Carbon Methane Nitrogen HHV
Monoxide Dioxide (MJ/m3)
32 488 15 2 3 10.4
0
• Syngas also contains small amounts of tar, alkali metals, sulfur,
nitrogen, and chlorine that must be removed before it can be
nitrogen and chlorine that m st be remo ed before it can be
catalytically upgraded to transportation fuels
Raw Syngas
Gasifier Particulate
Removal
Biofuel
Biomass
Tar Alkali Sulfur Nitrogen Catalytic
Oxygen/Steam Removal Removal Removal Removal Synthesis

14. Center for Sustainable Environmental Technologies
Gasification Efficiency
• Thermal efficiency - conversion of chemical energy of
solid fuel to chemical energy and sensible heat of
gaseous product
– High temperature, high-pressure gasifiers: >95%
– Typical biomass gasifiers: 70 - 90%
• Cold gas efficiency – conversion of chemical energy
of solid fuel to chemical energy of gaseous product
– T i l bi
Typical biomass gasifiers: 50 75%
ifi 50-75%
14

15. Center for Sustainable Environmental Technologies
Gasification Opportunities and Challenges
Gasification Opportunities and Challenges
• Advantages
– Tolerates relatively dirty biomass
feedstock
– Produces uniform intermediate
product (syngas)
– Proven method for “cracking the
lignocellulosic nut”
– Allows energy integration in
biorefinery
• Disadvantages
g
– Gas cleaning technologies still
under development
– Synfuel processing occurs at high
processing occurs at high ½ tpd gasification plant at ISU’s
pressures BioCentury Research Farm

16. Center for Sustainable Environmental Technologies
Syngas Upgrading to Fuels
Syngas Upgrading to Fuels
• Catalytic – performed at moderate
temperatures and high pressures
temperatures and high pressures
using metal catalysts
– Fischer‐Tropsch synthesis to
hydrocarbons suitable for fuels
– Methanol synthesis followed by
upgrading to gasoline
upgrading to gasoline
– Ethanol synthesis
• S
Syngas fermentation – performed
f t ti f d
at ambient temperature and
p
pressure using biocatalysts
g y

17. Center for Sustainable Environmental Technologies
Pyrolysis
Definition – thermal decomposition of
Definition thermal decomposition of
carbonaceous material in the absence
of oxygen
of oxygen

18. Center for Sustainable Environmental Technologies
Py Products
• Gas – non‐condensable gases like carbon dioxide,
carbon monoxide, hydrogen
• Solid – mixture of inorganic compounds (ash) and
carbonaceous materials (charcoal)
• Liquid – mixture of
water and organic Bio-
Bio-oil
compounds known as
bio‐oil recovered from
bio oil recovered from
pyrolysis vapors and
aerosols (smoke)
aerosols (smoke)

19. Center for Sustainable Environmental Technologies
The many faces of pyrolysis
The many faces of pyrolysis
Technology Residence Heating Rate Temperature Predominate
Time (C) Products
carbonization days very low 400 charcoal
conventional 5‐30 min low 600 oil, gas, char
gasification 0.5‐5 min moderate >700 gas
Fast pyrolysis 0.5‐5 s very high 650 oil
flash‐liquid <1 s high <650 oil
flash‐gas <1 s high <650 chemicals, gas
ultra <0.5 s very high 1000 chemicals, gas
vacuum 2‐30s
2 30s high <500 oil
hydro‐pyrolysis <10s high <500 oil
methano‐pyrolysis <10s high <700 chemicals
Mohan D., Pittman C. U. Jr., and Steele P. H. “Pyrolysis of Wood/Biomass for Bio‐oil: A
Critical Review” Energy & Fuels, 20, 848‐889 (2006)

20. Center for Sustainable Environmental Technologies
Carbonization (slow pyrolysis)
Carbonization (slow pyrolysis)
• Charcoal is the carbonaceous
residue obtained from heating
biomass under oxygen‐starved
bi d d
conditions.
• Charcoal word origin ‐ “the making
of coal.
of coal ”
• Geological processes that make coal
are quite different from those that
produce charcoal and properties are Charcoal yields (dry weight basis)
y ( y g )
quite different. for different kinds of batch kilns
• Charcoal contains 65% to 90% Kiln Type Charcoal Yield
carbon with the balance being Pit 12.5‐30
volatile matter and mineral matter
l til tt d i l tt Mound
Mound 2‐42
2 42
(ash). Brick 12.5‐33
• Antal, Jr., M. J. and Gronli, M. (2003) Portable Steel (TPI) 18.9‐31.4
The Art, Science, and Technology of
The Art, Science, and Technology of Concrete (Missouri) 33
Kammen, D. M., and Lew, D. J. (2005) Review of technologies for the production and use
Charcoal Production, Ind. Eng. of charcoal, Renewable and Appropriate Energy Laboratory, Berkeley University, March
1, http://rael.berkeley.edu/files/2005/Kammen‐Lew‐Charcoal‐2005.pdf, accessed
Chem. Res. 42, 1619‐1640 November 17, 2007.

21. Center for Sustainable Environmental Technologies
The many faces of pyrolysis
The many faces of pyrolysis
Technology Residence Heating Rate Temperature Predominate
Time (C) Products
carbonization days very low 400 charcoal
conventional 5‐30 min low 600 oil, gas, char
gasification 0.5‐5 min moderate >700 gas
fast pyrolysis 0.5‐5 s very high 650 oil
flash‐liquid <1 s high <650 oil
flash‐gas <1 s high <650 chemicals, gas
ultra <0.5 s very high 1000 chemicals, gas
vacuum 2‐30s
2 30s high <500 oil
hydro‐pyrolysis <10s high <500 oil
methano‐pyrolysis <10s high <700 chemicals
Mohan D., Pittman C. U. Jr., and Steele P. H. “Pyrolysis of Wood/Biomass for Bio‐oil: A
Critical Review” Energy & Fuels, 20, 848‐889 (2006)

22. Center for Sustainable Environmental Technologies
Fast Pyrolysis
y y
Fast pyrolysis - rapid
thermal decomposition
of organic compounds
in the absence of
oxygen to produce
predominately liquid
product
Biochar

23. Center for Sustainable Environmental Technologies
Fast Pyrolysis
Fast Pyrolysis
• Dry feedstock: <10%
• Small particles: <3 mm
• Moderate temperatures (400‐500 oC)
• Short residence times: 0.5 ‐ 2 s
• Rapid quenching at the end of the process
• Typical yields
Oil: 60 ‐ 70%
Char: 12 ‐15%
Gas: 13 ‐ 25%

24. Center for Sustainable Environmental Technologies
Bio‐Oil
Bio Oil
Source: Piskorz, J., et al. (1988) White Poplar
Pyrolysis liquid (bio‐oil) Spruce
from flash pyrolysis is a
from flash pyrolysis is a Moisture content, wt% 7.0 3.3
low viscosity, dark‐ Particle size, m (max) 1000 590
brown fluid with up to Temperature 500 497
15 to 20% ater
15 to 20% water Apparent residence time
Apparent residence time 0 65
0.65 0 48
0.48
Bio‐oil composition, wt %, m.f.
Saccharides 3.3 2.4
Anhydrosugars 6.5 6.8
Aldehydes 10.1 14.0
Furans 0.35 ‐‐
Ketones 1.24 1.4
Alcohols 2.0 1.2
Carboxylic acids 11.0 8.5
Water‐Soluble – Total Above 34.5 34.3
Pyrolytic Lignin 20.6 16.2
Unaccounted fraction 11.4 15.2

25. Center for Sustainable Environmental Technologies
Energy Efficiency
Energy Efficiency
• Conversion to 75 wt‐% bio‐oil translates to energy
efficiency of 70%
ffi i f 70%
• If carbon used for energy source (process heat or
slurried with liquid) then efficiency approaches 94%
slurried with liquid) then efficiency approaches 94%
Source: http://www.ensyn.com/info/23102000.htm

26. Center for Sustainable Environmental Technologies
Fast Pyrolysis Opportunities and Challenges
Fast Pyrolysis Opportunities and Challenges
• Advantages of bio oil:
Advantages of bio‐oil:
– Can be upgraded to drop‐in
( y
(hydrocarbon) fuels
)
– Opportunities for distributed
processing
¼ ton per day fast pyrolysis pilot plant at
• Disadvantages of bio‐oil ISU BioCentury Research Farm
– High oxygen and water content makes bio‐oil inferior to
High oxygen and water content makes bio oil inferior to
petroleum‐derived fuels
– Phase‐separation and polymerization and corrosiveness
make long‐term storage difficult

27. Center for Sustainable Environmental Technologies
Applications of Bio‐Oil
Applications of Bio‐Oil
• Stationary Power
Stationary Power
• Commodity Chemicals
• Transportation Fuels
i l

28. Center for Sustainable Environmental Technologies
And Sugar and Bioasphalt!
And Sugar and Bioasphalt!
Heavy Ends
Sugar solution (>20 wt%)
Water
Wash
Raffinate (mostly phenolic
oligomers derived from lignin)

29. Center for Sustainable Environmental Technologies
Biochar
• Carbonaceous residue from
pyrolysis of biomass
pyrolysis of biomass
• Yields range from 5‐40% of
biomass depending upon process
biomass depending upon process
conditions
• Fine, porous structure
,p
• Several potential applications,
the most intriguing being dual
g g g
use as soil amendment and
carbon sequestration agent

30. Center for Sustainable Environmental Technologies
Terra Preta: Anthropogenic Soils from Biochar
Terra Preta: Anthropogenic Soils from Biochar
• Created hundreds of years
y Terra Preta Oxisol
ago by pre‐Colombian
inhabitants of Amazon
Basin
• Result of slash and char
agriculture
• Much higher levels of soil
organic carbon
• F
Far more productive than
d i h Applied to the land, biochar serves as
undisturbed both soil amendment and carbon
oxisol soils sequestration agent
Glaser et al. 2001. Naturwissenschaften (2001) 88:37–41

31. Center for Sustainable Environmental Technologies
Biochar s
Biochar’s Impact
• Biochar increases soil cation exchange Increases:
capacity (CEC), holding ammonium ions
capacity (CEC), holding ammonium ions g
Cation Exchange
(NH4+) and other cations in the soil Capacity
Soil Organic Matter
• Biochar adsorbs soil organic matter which g
Drainage
contains plant‐available organic nitrogen1
Aeration
• Biochar’s low bulk density increases soil
aeration and water drainage, lessening the
g , g
Decreases:
D
likelihood of denitrification (NO3‐  N2O
N2) and associated N2O emissions2 Soil Bulk Density
Denitrification
• Addition of biochar has been shown to
Addition of biochar has been shown to
N2O Emissions
decrease nutrient leaching (nitrate,
phosphate, cations) from manure Nutrient Leaching
amendments3
1. Laird, D. A., Agron J 2008, 100, (1), 178-181.
2. Rogovska, et al. North American Biochar Conference, Boulder, CO, Aug 2009.
3. Laird, et al. 2008 GSA-SSSA-ASA-CSA Joint Meeting, Houston, TX, Oct 2008.

32. Center for Sustainable Environmental Technologies
GHG Impacts of Soil Application of Biochar
GHG Impacts of Soil Application of Biochar
Increased CO2 Competition
emissions due between food
to enhanced and biomass
soil microbial crops may
respiration increase land
under cultivation.
+
0
_
Increase C Increased Reduce CO2 Reduce N2O Increase C Reduce CO2
input to soil yields may emissions emissions sequestration emissions due
due to decrease the due to bio-oil from soils in soils to decreased
enhanced amount of displacing due to better (Biochar C is use of lime
plant growth land needed fossil fuel soil aeration very stable) and fertilizer
to grow food.

33. Center for Sustainable Environmental Technologies
Proof‐of‐Concept: Terra Preta in Brazil
Proof‐of‐Concept: Terra Preta in Brazil
Terra Preta Oxisol

34. Center for Sustainable Environmental Technologies
Lovelock on Biochar
Lovelock on Biochar
“There is one way we could
save ourselves and that is
through the massive burial of
through the massive burial of
charcoal. It would mean
farmers turning all their
farmers turning all their
agricultural waste…into non‐ James Lovelock in an
biodegradable charcoal, and otherwise pessimistic
burying it in the soil.” interview with New
Scientist Magazine
(January 2009) on our
prospects for halting global
t f h lti l b l
climate change

35. Center for Sustainable Environmental Technologies
ISU Facilities to Support Thermochemical Research
Lab-scale pyrolyzers
Micropyrolyzers & Batch and fixed bed
and gasifiers
bio-oil analysis catalytic upgrading reactors
ISU Biorenewables Laboratory
Quarter-ton/day pilot plant fast pyrolyzer
Half-ton/day p
y pilot p
plant
oxygen-blown gasifier
ISU BioCentury
Research Farm