1. Pyrolysis of Biomass to Produce Bio-oil, Biochar and Combustible Gas
Energy Postgraduate Conference 2008
John Edwards
School of Engineering and Advanced Technology
Massey University 1

2. Heat introduced, O2 excluded
What is Pyrolysis?
“Pyrolysis is thermal cracking in the absence of oxygen.” Cedric Briens
“Pyrolysis is the thermal decomposition of organic material at elevated temperatures, in the absence of gases such as air or oxygen.” Greenpeace
Heat introduced, O2 excluded
An endothermic reaction 2

3. What is Biomass?
“Biomass is all non-fossil organic materials that have an intrinsic chemical energy content.” Ralph Sims
Distillers’ Grains, Coffee Grounds, Grape Seeds and Skins, Sugarcane Bagasse, Sawdust and Tobacco Leaves. 3

4. What Pyrolysis of Biomass Is Not
1. New
Pyrolysis dates back to at least ancient Egyptian times.
2. The Holy Grail of Renewable Energy. 4

5. Pyrolysis of Biomass Combustible Gas HEAT Bio-Oil Vapour Biochar
Condensation
Biomass
Biochar 5

6. The Organic Chemistry Pyrolytic reaction using cellulose:
Liquid Bio-Oil
Combustible Gas
Biochar
Water of Pyrolysis
HEAT
3C6H10O5
C6H8O +8H2O +CH4+2CO+2CO2+ 7C 6

7. Some Advantages of Pyrolysis of Biomass
Carbon neutrality
Utilises otherwise waste biomass
Potential to be self-sustaining energy-wise
Increases bulk and energy density of biomass
Source of valuable chemicals
Biomass source can be decoupled from the energy utilisation 7

8. Fast Pyrolysis of Biomass Objective to maximize liquid yield
The three main variables in the pyrolysis process are:
Reaction temperature.
Biomass heating rate.
Vapour residence time.
Moderate temperatures ≈ 500°C and short vapour
residence time are required to maximize liquid yield. 8

9. Fast Pyrolysis of Biomass
Product yields (dry feed basis) for pyrolysis of wood.
Mode
Conditions
Liquid
Char
Gas
Fast pyrolysis
Moderate temperature,
short residence time
75%
12%
13%
Slow Pyrolysis
Low temperature, very long residence time
30%
35%
Gasification
High temperature, long residence time. 5%
10%
85%
A.V.Bridgwater 9

10. Bubbling fluidised bed method
Biomass feed
A.V. Bridgwater et al 10

11. Yields vs Reaction Temperature for Grape Seeds and Skins 5 seconds residence time
Maximum liquid yield
Gas
Liquid
Char 11

12. Grape Skin Pyrolysis Yields vs Residence Time Reaction Temperature 500°C

13. Heat of pyrolysis vs heating value of product gas for grape skins
Self sustaining
Heat of pyrolysis
Heating value of product gas 13

14. Production of Ethanol from Corn
1litre of ethanol = 800grams of distillers’ grains
Distillers’ grain has a heating value of 6 to 20 MJ/kg
Bulk density ≈ 400kg m-3
Mike Jacobson 14

15. Options for Distillers’ Grains
Sequestration of Biochar
Heat of Pyrolysis provided by combustible gas
CO2
Ethanol Production
Pure Ethanol
Distillers’ Grains
Pyrolysis 15

16. Bulk and Energy Densities
Comparisons of Bulk and Energy Densities for Biomass and Bio-Oil
Density
Energy Density
Kg m-3
MJ kg-1
GJ m-3
Green whole wood chips
350
9.6
3.4
Pyrolysis Bio-Oil
1200
18.0
21.6
Ratio
1:3.4
1:1.9
1:6.4
Phillip C. Badger, Peter Fransham 16

17. Mobile Pyrolysis Unit
400 kg/h Demo Unit 17

18. Comparison of Bio-oil with Heavy Fuel oil
Physical property
Pyrolysis Bio-oil
Heavy Fuel Oil
Water, wt%
15-30
0.1
Specific Gravity
1.2
0.94
Heating Value (MJ/kg)
13-19 40
Solids, wt%
Viscosity, (at 50°C) (cP)
40-100
180 pH
2.5
Oxygen, wt%
35-60
Dinesh Mohan et al 18

19. The Challenges For upgrading of bio-oil to transport fuels
Low volatility
Low heating value.
High viscosity
Corrosiveness
Coking
Every biomass is different! 19

20. Alternatives to upgrading
Gasification of bio-oil to syngas
Combination of bio-oil with diesel 20

21. Opportunities
New Zealand has a plethora of biomass from forest and agricultural waste, for example
Bio-oil and biochar co-production can be economically, environmentally and climate friendly 21

22. Conclusions Pyrolysis of Biomass
• Rapidly developing technology
• Added Value
Economy
Carbon negative solution
Environment 
Economy
Environment 
• Increased bulk and energy density
More work needs to be done for upgrading
to transport fuels 22

23. Distillers’ Grains Biomass

24. Distillers’ Grain Biochar

25. Distillers’ Grain Bio-oil

26. Queen Elizabeth II Technicians’ Study Awards
Acknowledgements
Queen Elizabeth II Technicians’ Study Awards
Massey University
Ann-Marie Jackson
Professor Don Cleland
Professor Clive Davies
The University of Western Ontario
Professor Franco Berruti
Professor Cedric Briens
Dr. Lorenzo Ferrante
Mohammad Latifi
Ran Xu
Rohan Bedmutha
Mike Jacobson
Shirley and Lukey

27. Thank you Questions? John Edwards
School of Engineering and Advanced Technology
Massey University
Palmerston North