Biomass Feedstocks

1. Biomass Feedstocks

6 CO2 + 6 H2O
C6H12O6 + 6 O2
sunlight
Potential : 15% of the world’s energy by 2050.
Fischer and Schrattenholzer, Biomass and Bioenergy 20 (2001) 151-159.
Crop residues
Forest residues
Energy crops
Animal waste
Municipal waste
Issues: Biomass Availability, Cost and Physical
and Chemical Properties

2.

Biorefineries of the Future
Products
Fuels:
Ethanol
Renewable Diesel
Methanol
Hydrogen
Electricity
Heat
Chemicals:
Biomass
Feedstocks
•Trees
•Grasses
•Bio-product Crops
•Agricultural Crops
•Agricultural Residues
•Animal Wastes
•Municipal Solid Waste
Conversion
Processes
•Enzymatic Fermentation
•Gas/liquid Fermentation
•Acid Hydrolysis/Fermentation
•Gasification
•Product Synthesis from Syn-gas
•Combustion
•Co-firing
• Plastics
• Solvents
• Pharmaceuticals
• Chemical Intermediates
• Phenolic Compounds
• Adhesives
• Furfural
• Fatty acids
• Acetic Acid
• Carbon black
• Paints
• Dyes, Pigments, and Ink
• Detergents
• Etc.

3. Biodiesel (B100)

• ASTM PS 121 Biodiesel Fuel Standard
– similar to ASTM D 975
• Used pure or blended with #2 or #1 diesel,
JP8, Kerosene, or Jet A.
– Use pure or blends in existing diesel engines
• on road, marine, off road, stationary, turbines, air craft
– B100 has 10% less energy than #2 diesel
– Power loss and fuel economy loss
• 1% for every 10% biodiesel in fuel
– Reduces CO, PM, toxicity of PM, and HC
emissions

4. Handles Just Like Diesel

• No engine modifications required for B20, if
using B100 then:
• rubber seals may deteriorate
• metals (Zn, Cu, W, bronze, brass) lead to oxidation
• Storage stability up to 6 months
• More sensitive to cold weather (Cloud pt =
0oC)
• Cetane number = 47 to 70
• No sulfur, no aromatics, 11% oxygen by wt
• Stays blended even in presence of water
• Use biocides if needed

5.

Next Generation Biology will Reduce Costs of
Cellulosic Ethanol Production: SSF
SSF
Gulf Oil’s SSF, 1978

6.

Technical Barrier Areas for $1.07
Biochemical Ethanol
Feedstock Variation
Feedstock Quality
Feedstock Cost
conversion
Pretreatment
Conditioning
Enzyme Cost
Enzyme
Production
HSF*
Cofermentation
of C5 & C6
Sugars
Enzymatic
Hydrolysis
Product
Recovery
Sugar Losses
Xylose Yield
Xylose Degradation
Solids Loading
Reactor Costs
Glucose Yield
Solids Loading (titer)
Residue
Processing
Ethanol Yields
Ethanol Concentration
Rate
Hydrolyzate Toxicity
By-products
*Hybrid Saccharification & Fermentation - HSF
Products

7.

Feedstock Engineering
Increase crop
production
(agronomics and plant
engineering)
Increase composition
of desirable
polysaccharides
(cellulose)
Decrease composition
of undesirable
polymers (lignins)
www.nefb.org/ ag-ed/corn.html
Glucan
36.1 %
Xylan
21.4 %
Arabinan
3.5 %
Mannan
1.8 %
Galactan
2.5 %
Lignin
17.2 %
Protein
4.0 %
Acetyl
3.2 %
Ash
7.1 %
Uronic Acid
3.6 %
Non-structural
Sugars
1.2 %

8. Constituents of Biomass

• Lignin: 15%–25%
• Complex aromatic
structure
• Very high energy content
• Resists biochemical
conversion
H CO
3
HO
• Cellulose: 38%–50%
• Most abundant form of
carbon
in biosphere
• Polymer of glucose, good
biochemical feedstock
H CO
3
O
3
O
O
OH
OCH
OCH OCH3
3
O
3
3
HO
OH
O
OCH
3
HO
O
OH
O
OH
OH
HO
OH
OH
O
O
O
OH
O
OH
HO
O HO
O
OH
OH
HO
O
O
OH
OH
OH
O
O
OH
HO
O
O
OH
O
OH
OH
O
OH
O
OH
HO
HO
O HO
O
OH
O
OH
OH
HO
O HO
OH
OH
O
O
O HO
OH
OH
O
OH
OH
O
O
HO
O HO
OH
O
OH
OH
OH
O
O
OH
O
O
OH
O
OH
O
O HO
O
OH
OH
O HO
OH
OH
O
HO
O HO
O
OH
O
HO
O HO
O
OH
HO
OH
OH
O
OH
OH
OH
O
O
OH
OH
O
O HO
O
O
O HO
OH
OH
O
HO
O HO
OH
OH
O
O
OH
OH
OH
O
OH
O
O HO
O
OH
OH
OH
OH
OH
O
O HO
O
HO
O
O
O
OH
HO
H CO
3
OCH
3
HO
O HO
OH
HO
OH
OH
HO
OH
OH
O
O
OH
OH
O
O
O
O HO
O
HO
OCH OCH3
3
OH
HO
O
OH
OH
OH
H CO
3
OCH
3
3
O
OH
O
OH
O
O
OH
O
OCH
O
HO
O CH
OH
HO
• Hemicellulose: 23%–32%
• Xylose is the second most
abundant sugar in the
biosphere
• Polymer of 5- and 6-carbon
sugars, marginal
biochemical feed
OCH
OH
OH

9. Plant Cell Wall Models

Buckeridge et al., 2004

10. Plant Cell Wall Models

J. Bidlack, M. Malone, and R.
Benson. Proc. Okla. Acad. Sci.
72:51-56 (1992)

11. Hemicellulose Structure

Ac
Hemicellulos
e Structure
O
HO
O
HO
O
O
O
O
O
O
HO
OH
O
• Complicated
branching and bond
structure
a-L-arabinofuranosidase
Feruloyl esterase
OH
OCH
OCH
3
3
OH
R 3O
OR
a-L-arabinofuranosidase
2
O
O
R 1O
O
O
O
HO
O
O
O
O
O
O
O
Ac
O
O
Ac
Ac
Ac
O
O
O
HO
O
O
O
O
HOOC
Ac
O
O
HO
O
O
Ac
O
O
OH
O
O
Ac
Ac
H 3C O
OH
Debranched components
a-D-glucuronidase
Ac
O
O
• Highly variable across
species
Xylans, mannans
Glucomannans
Xyloglucans
Etc.
OH
Endoxylanase
• i.e. Esters cleaved
at alkaline pH,
elevated To
–
–
–
–
O
HO
OH
O
O
Ac
O
O
O
O
O
OH
O
Ac
O
O
HO
Ac
O
O
HO
O
HO
O
Ac
O
O
O
OH
O
O
OH
OH
O
OH
O
O
Endoxylanase
O
OH
O
O
OH
OH
O
Ac
OH
O
Ac
O
O
OH
O
O
O
OH
Ac
Xylooligomers
AE
O
HO
Ac
O
O
OH
AE
Ac
Ac
OH
O
O
HO
OH
O
HO
OH
b-Xylosidase
HO
OH
O
b-Xylosidase
O
HO
O
O
OH
+
OH
Acetic Acid
O
O
O
OH
OH
Ac
AE
DEPOLYMERIZING
– Affect solubility and
enzyme accessibility
– Different bonds
affected by different
pretreatments
OH
O
O
HO
OH
OH
O
O
O
O
HO
O
O
O
AXE
O
O
O
O
Ac
Ac
Ac
O
O
O
AXE
OH
O
AXE
O
O
O
O
HO
Ac
Ac
Ac
AXE
DEBRANCHING
Ac

12. Biofuels from Biomass

BIOMASS
CORN
YEAST
SUGAR
CANE
SUGAR
EXTRACT
WOOD
CORN
STOVER
HOLOCEL
LULOSE
ETHANOL
FERMENT
SUGAR
CANE
BAGASSE
ACID&
HEAT
LIGNIN
BIOFUEL
YEAST
ENZYMES
SUGARS
ETHANOL
FERMENTATION
• Other organisms produce butanol or isobutanol

13. Diesel Biofuels from Biomass

OILSEEDS
SOYBEAN
CANOLA
PRESS
METHANOL
BIODIESEL
(FAMES)
VEGETABLE
OIL
HEAT, BASE
HYDROGEN
CATALYST
HEAT & PRESSURE
GREEN
DIESEL
• Green diesel is virtually identical to petroleum-derived diesel, can
make a true jet fuel as well

14. Thermochemical Pathways

Biomass Feedstocks
Intermediates
Transportation Fuels
Fermentation
Catalytic Synthesis
Lignocellulosic Biomass
Gasification
Syngas
(wood, agricultural, grasses)
Methanol Synthesis
Pyrolysis &
Liquefaction
Agricultural Residues
(stover, bagasse)
FT Synthesis
Pretreatment
& Hydrolysis
Bio-Oils
Lignin
Hydroprocessing
Catalytic Upgrading
APP
Sugars
Catalytic Pyrolysis
Aq-Phase Reforming
Ethanol &
Mixed Alcohols
Diesel
Methanol
MTG
Gasoline
Gasoline & Diesel
Gasoline & Diesel
Diesel
Gasoline
Hydrogen
• Gasification is high temperature with air or steam
• Pyrolysis is moderate temperature
14

15. Comparison of feeds and processes

• Biochemical is low temperature but long times
• Thermochemical is high-throughput but high
temperature and sometimes high pressure
• Not enough sugar except perhaps sugar cane in
Brazil
• Oil-seed yields too low for high impact
• Ligno-cellulosic feeds high yields but more
difficult to process
• Algae has high yields but many processing
difficulties

16. Sustainability of Cellulosic Ethanol

Requires Much Less Fossil Energy Than Gasoline from
Petroleum or ethanol from corn
Total Btu spent for 1 Btu available at fuel pump
3
From Biomass
Btus Required per Btu of Fuel
From Coal and Natural Gas
2.5
Fuel-to-Petroleum Ratio = 10
From Petroleum
45% Efficiency
2
57% Efficiency
Fuel-to-Petroleum Ratio = 0.9
1.5
81% Efficiency
Energy in
the Fuel
1
0.5
0
Gasoline
Corn Ethanol
Cellulosic Ethanol
Based on “Well to Wheels Analysis of Advanced Fuel/Vehicle Systems” by Wang, et. al. (2005)
National Renewable Energy
Laboratory
Innovation for Our Energy

17. Is there enough land?

• If biomass competes with food crops for farm
land, then food prices will rise causing the
poor to suffer

18.

19. The 1.3 Billion Ton Biomass Scenario

Billion Barrel of Oil Equivalents
Based on ORNL & USDA Resource Assessment Study by Perlach et.al. (April 2005)
http://www.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf
Have enough land to replace a large amount of oil but still need appropriate
import and agriculture policies to prevent driving up fuel prices and getting too
much fossil input into biofuels

20. When will the fuels come?

• Corn ethanol and biodiesel are here now to
some extent
• Cellulosic ethanol, mixed alcohols, and green
diesel are rather near, 15% ethanol will be
allowed in near future
• Hydrocarbons from biomass are further away
• Algal fuels are a long way off

21. Life Cycle Assessment: Definition

LCA
• Is a systematic analytical method
• Used to quantify environmental benefits and drawbacks
of a system
• Performed on all operations, cradle-to-grave, resource
extraction to final disposal
• Ideal for comparing new technologies to the status quo
• Helps to pinpoint areas that deserve special attention
• Reveals unexpected environmental consequences (no
showstopping surprises)

22.

System Concept in Life Cycle Assessment
waste materials
Extraction
process
nonrenewable
energy
energy
raw materials
Process
nonrenewable
materials
emissions
Waste
disposal
net emissions
energy
energy
Intermediate
feedstock
emissions
Process
energy
Process
emissions
energy
Intermediate
feedstock
Intermediate
feedstock
energy
emissions
emissions
emissions
Process
of
Interest
energy
raw materials
final product
emissions
Extraction
process
Life cycle system boundary

23.

GWP = global warming potential

24.

GWP = global warming potential

25.

An integrated gasification combined cycle (IGCC) is
a technology that uses a high pressure gasifier to turn
coal and other carbon based fuels into pressurized
gas—synthesis gas (syngas). It can then remove
impurities from the syngas prior to the power
generation cycle.
GWP = global warming potential

26.

GWP = global warming potential

27. Summary

• Energy is the driver of everything we do in today’s
society
• Energy has an enormous impact on the environment
• Looking at the emissions of the production plant is not
enough
• LCA allows us to evaluate the broader environmental
impacts
• Renewable energy
– Not zero impact, but lower and more sustainable
– Different impacts; be careful of shifts (e.g., CO2 to land-use)
– Often more distributed impact
• Solutions do exist to reduce our energy / environmental
problems