1. Torrefaction for biomass upgrading into commodity fuels
Jaap Kiel
IEA Bioenergy Task 32 workshop “Fuel storage, handling and preparation and system analysis for
biomass combustion technologies”, Berlin, 7 May 2007
Presentation overview
• ECN
• Torrefaction principles
• ECN TOP technology
• Economics
• Development status and market implementation
2 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
1
2. Energy research Centre of the Netherlands
in the dunes of North Holland
ECN develops high-quality knowledge and technology
for the transition to a sustainable energy supply and
brings it to the market
• Independent energy
research institute
• 650 staff
• Annual turnover:
80 million EURO
• Activities:
- Biomass, Solar, Wind
- Fuel Cell Technology
- Clean Fossil Fuels
- Energy Efficiency
- Policy Studies
3 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Torrefaction for biomass upgrading
general process description
Gas Temperature: 200-300 °C
Torrified
Biomass 0.3 0.1 biomass Pressure: near atmospheric
1 0.7
Torrefaction Absence of oxygen
1 0.9
Product: solid fuel
0.9 Particle size < 4 cm thickness
Energy densification (E/kg) 1 = 1.3
0.7
Residence time 10-30 min
mass energy Heating rate: <50 °C/min
4 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
2
3. From biomass/waste to commodity fuels
Woody biomass Agricultural residues
Friable and less fibrous
19 - 22 MJ/kg (LHV, ar) Superior fuel properties:
Hydrophobic • Transport, handling, feeding
Preserved
Reduced contaminant level • Milling
Homogeneous • Combustion/gasification
• Feedstock bandwith
• Standardisation
Torre
fac
pulve tion and
risati
Mixed on
waste
Pelle
Tenacious and fibrous tisati
on
Fuel powder
10 - 17 MJ/kg (LHV, ar)
Hydrophilic
Vulnerable to biodegradation
Contaminated Bulk density 750-850 kg/m3
Heterogeneous Bulk energy density 15-20 GJ/m3 Fuel pellets
5 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Hemicellulose Lignin Cellulose
Decomposition regimes
Extensive
E E
300 Devolatilisation 300
and
carbonisation
(E)
D
TORREFACTION
250 D D 250
Limited
devolatilisation
Temperature (°C)
Temperature (°C)
and
carbonisation (D) C
200 200
C
depolymerisation
and
recondensation
(C)
150 150
glass transition/ A
softening (B)
drying (A)
A
100 100
Hemicellulose Lignin Cellulose
6 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
3
4. Starting points ECN TOP technology development (1)
• Torrefaction (combined with pelletisation) has the potential of becoming
a key unit operation in biomass upgrading schemes for a wide range of
applications, including:
− Biomass storage and (long-distance) transport – biomass import
− Co-firing in pf boilers
− (Co-)firing in entrained-flow gasifiers for producing power (IGCC) or
transportation fuels (e.g., Fischer-Tropsch diesel)
− Small-scale pellet boilers and stoves
⇒ Torrefied biomass pellets may become a biomass commodity fuel
7 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Starting points ECN TOP technology development (2)
• Torrefaction principle not new, but many aspects relevant to application
for upgrading biomass into biomass fuel for thermal conversion
processes were not addressed, including:
− Scale of operation in relation to reactor technology and process
layout
− Characterisation and quantification of product quality and how this
relates to process conditions
− Nature and quantity of emissions
− Prospects of heat integration including utilisation of the energy
containing torrefaction gases
− The economic viability of torrefaction as a biomass upgrading
technique for bulk applications
⇒ 2002 start ECN TOP technology development
8 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
4
5. 5 kg/h screw
Proof-of-concept approach reactor
Pellet press (batch) Pellet quality
Continuous screw
reactor (pyromaat)
Torrefied
Biomass biomass
Batch reactor Cutting mill Grindability
TGA analysis
Lab-scale combustion
Simulator (LCS)
Combustibility
Torrefaction
gas
Sampling methods 20 l batch reactor
Process
Torrefaction
Analysis methods simulation
database
&
design tools
Product distribution (M & E yields)
9 Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Torrefaction
Typical experimental results
Gas phase composition
CO 0.1 %
CO2 3.3 %
H2O 89.3 %
acetic acid 4.8 %
furfural 0.2 %
methanol 1.2 %
formic acid 0.1 %
remainder 1.0 %
Tad = 1045 ºC
Torrefaction
32 min, 260 ºC
Feed: Willow Torrefied Willow
Size: 10 - 30 mm Size: 10 - 30 mm
LHV = 14.8 MJ/kg (ar) LHV = 18.5 MJ/kg (ar)
MC = 14.4% MC = 1.9%
Mass yield: 75.3% (ar)
Fixed carbon: 16.8 % Fixed carbon: 22.1%
Energy yield: 94.3% (ar)
10
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
5
6. Grindability of (torrefied) biomass
90 360
C(270,21)
80 C(280,18) 320
C(290,12)
70 280
Power consumption (kWe/MWth)
W(290,24)
W(260,24)
chipper capacity (kWth)
60 240
Willow (MC=10-13%)
50 Willow (dried) 200
Cutter wood
40 AU bituminous coal 160
Borssele run
30
demolition wood
120
D(300,11)
20 80
10 40
- -
- 0.5 1.0 1.5 - 0.2 0.4 0.6 0.8 1.0
average particle size (mm, volume based)
average particle size (mm, volume based)
Torrefaction leads to a dramatic decrease in required milling power
and increase in milling capacity
11
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Torrefaction of willow (280 oC, 17.5 min) 100%
Product distribution mass
composition
Permanent gases 75%
energy
94.9
100 composition
87.5
90 50%
Mass y ield
80
Energy y ield
70
25%
60
50
0%
40
CO CO2 Other
30
20 Organics
8.0
10 1.4 0.1 1.7 1.6 1.4 3.4 70%
0 60% mass composition
Solid Permanent Organics Lipids Reaction 50% energy composition
Gas Water
40%
Main product groups (dry basis) 30%
20%
10%
0%
ol
r
ol
te
ol
de
id
de
id
e
n
he
ton
an
en
yd
no
an
eta
ac
Ac
hy
hy
Ot
ce
eth
Ph
eh
ta
th
ic
lac
lde
lde
c
me
ya
bu
eti
ion
ald
M
thy
ra
eta
ox
2-
Ac
2-
fur
op
Fu
y-
Me
dr
n-
Ac
Pr
2-
ox
2-
Hy
ra
yl -
dr
Fu
eth
Hy
1-
M
5-
12
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
6
7. Combustion reactivity of torrefied wood
Lab-scale Combustion Simulator
experiments
high-volatile coal low-volatile coal torr. (300° demolition wood
C)
HVC (LOI) LVC (LOI) torr. (300° demolition wood (LOI)
C)
torr. (280° prune wood
C) torr. (280° prune wood (LOI)
C) torr. (280° demolition wood
C)
torr. (280° demolition wood (LOI)
C) prune wood (fresh) prune wood (fresh, LOI)
100
90
conversion [%] or LOI [% d.b.]
80
70
60
50
40
30 High reactivity for
20 torrefied wood
10
0
0 500 1000 1500 2000 2500
time [ms]
13
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Semi-industrial pelletisation tests
Features:
• 10 kg/h
• No automatic moisture supply
• Preliminary findings:
− Easy pelletisation
− Low energy input required
− Pellet quality strongly dependent on
pelletisation conditions
14
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
7
8. TOP pellets vs. wood pellets
Properties unit Wood Torrefied biomass Wood pellets TOP pellets
low high low high
Moisture content % wt. 35 3 7 10 1 5
Calorific value (LHV)
dry MJ/kg 17.7 20.4 17.7 17.7 20.4 22.7
as received MJ/kg 10.5 19.9 15.6 16.2 19.9 21.6
Mass density (bulk) kg/m3 550 230 500 650 750 850
Energy density (bulk) GJ/m3 5.8 4.6 7.8 10.5 14.9 18.4
Pellet strength - - Good Very good
Dust formation Moderate High Limited Limited
Swelling / Water Limited swelling /
Hygroscopic nature Water uptake Hydrophobic
uptake Hydrophobic
Biological degradation Possible Impossible Possible Impossible
Seasonal influences
High Poor Moderate Poor
(noticable for end-user)
Handling properties Normal Normal Good Good
15
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
ECN directly heated torrefaction technology
Air
Features:
Utillity fuel
• High energy efficiency (> 90%)
• Heat integration Flue gas
• Conventional drying and
pelletisation
Combustion
• Compact moving bed
Torrefaction
technology gas
Gas
• Cost effective recycle
Biomass TOP pellets
Drying Torrefaction Cooling Pelletisation
∆P
Flue gas
15-20% Heat exchange
Flue gas
moisture
16
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
8
9. ECN torrefaction technology
Innovative moving bed reactor
• Compact reactor
• Small footprint
• High heat transfer rates
• Accurate T-control
• Uniform product quality
• Feedstock flexibility
• Low capital investment
Pilot-scale torrefaction reactor at ECN
17
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Total capital investment – study estimate (TOP pellets vs. wood pellets)
Total Capital Investment TOP and Pelletisation
(Feedstock: 180 kton/a woodchips @ 50%mc)
8
7
6
5
TCI (MEuro)
Drying
4
Torrefaction
3 Size Reduction and Pelletisation
Storage
2 Indirect Cost
Working Capital
1
0
TOP Process Conventional Pelletisation
18
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
9
10. Total production cost (TOP pellets vs. wood pellets)
4,0
3,5
Production Cost Indication (Euro/GJ product)
3,0
2,5
2,0
1,5
1,0
0,5
0,0
Green Wood Saw Dust 47 MW / 47 MW / 47 MW / 47 MW / 47 MW /
Pellets Pellets 75 kton/a 75 kton/a 75 kton/a 36 kton/a 112 kton/a
MC = 50% MC = 35% MC = 25% MC = 35% MC = 35%
BASE CASE
Total Cost Other Power
Support Fuel Personnel Maintenance
Depreciation and Financing Feedstock (=0 Euro/tonne)
19
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
Chain study (TOP pellets vs. wood pellets)
TOP process
Sawdust Logistics
(South Africa)
0.7 EUR/GJ <2.0 EUR/GJ
2.0 EUR/GJ
<4.7 EUR/GJ
Favourable (Co-)firing
coal-fired power stations
economics! Higher co-firing capacity
or entrained-flow gasifiers
Lower capital investment
Higher co-firing flexibility North-West Europe
and availability
2.3 EUR/GJ 5.9 EUR/GJ
0.7 EUR/GJ Conventional 2.9 EUR/GJ
Sawdust Pelletisation Logistics
(South Africa)
20
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
10
11. Road map ECN TOP technology development
capacity 5-10 kg/h 100 kg/h 20 kton/a 60-100 kton/a
Green Proof-of- Prototype Technical Commercial
Proof-of-concept
biomass principle (pilot-scale) demonstration demonstration
Time 2002 2003 2004 2005 2006 2007 2008 2009 2010
Proof-of- Prototype Technical
Waste Proof-of-concept
principle (pilot-scale) demonstration
Proof-of-concept Prototype (pilot-scale evaluation) Technical demonstration
•Experimentally based process design •Pilot plant / prototype technology •Demonstration plant (semi-commercial)
•Technology identification •Demonstration technical feasibility •Technical feasibility (refined design)
•Knowledge base torrefaction •Process and product characterisation (design data) •Product applications (large scale)
•Experimental infrastructure torrefaction •Economic evaluation full-scale •Economic evaluation full-scale
•Economic evaluation full-scale (preliminary estimate 20%) (definite estimate <10%)
(study estimate 30%) •Business plan(s) •Business plan(s)
•Set-up pilot phase of development (technical demo, semi-commercial) (commercial operation)
21
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
ECN TOP technology development – 2007 activities
• Pilot-scale testing
− Validation of reactor and process concept
− Optimisation of process conditions for a broad feedstock
range
− Industrial pelletisation tests
− Extensive quality evaluation TOP pellets
(e.g., hygroscopic nature, biodegradation, strength, milling
characteristics, combustion/gasification reactivity)
• Demonstration plant basic design
• Business plan for technical demonstration(s) through BO2
Energy Concepts
• Continued basic R&D (co-operation with TU Eindhoven)
− Contaminated biomass (residues) and waste
40-100 kg/h torrefaction
pilot-plant at ECN
22
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
11
12. In conclusion
• ECN TOP technology allows cost effective production of commodity fuels from a
wide range of biomass/waste feedstocks with a high energy efficiency (>90%)
• ECN TOP fuels show:
− High energy density
− High water resistance
− No/Limited biological degradation
− Excellent grindability
− Good combustion properties
• Fields of application:
− Long distance biomass transport
− Co-firing in pf boilers
− (Co-)firing in entrained-flow gasifiers
− Small-scale pellet boilers/stoves
• In 2007 pilot-plant testing and
initiation of demo-projects
23
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
For further information please contact:
Dr.ir. Jaap Kiel
e: kiel@ecn.nl
t: +31 224 56 4590
w: www.ecn.nl
ECN
P.O. Box 1
NL 1755 ZG Petten
the Netherlands
24
Meeting Cargill, 15 May 2006 Torrefaction for biomass upgrading into commodity fuels – Jaap Kiel
12