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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Mobile Pyrolysis Unit 400 kg/h Demo Unit 17

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% 0.2-0.1 0.2-1.0 Viscosity, (at 50°C) (cP) 40-100 180 pH 2.5 Oxygen, wt% 35-60 0.6-1.0 Dinesh Mohan et al 18

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

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

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

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

Distillers’ Grains Biomass

Distillers’ Grain Biochar

Distillers’ Grain Bio-oil

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

Thank you Questions? John Edwards School of Engineering and Advanced Technology Massey University Palmerston North email: J.Edwards@massey.ac.nz