ECNs moving bed
torrefaction technology in
light of desired product
qualities
F. Verhoeff
J.H.A. Kiel
R.W.R. Zwart
March 2012
ECN-L--12-079
ECNs moving bed torrefaction technology in light of desired product qualities
Fred Verhoeff, Jaap Kiel, Robin Zwart
Torrefaction of Biomass Workshop, University of Leeds, 28 March 2012
www.ecn.nl
Presentation overview
 Introduction
 ECN’s torrefaction development status
 Product characteristics
 Exothermicity
 Self heating
 SECTOR project
 Conclusions
Energy research Centre of the Netherlands
 Core activities
 Sustainable energy technology development
 R&D services to industry
 Feasibility studies, system & technology
assessments
 Largest Dutch energy
R&D institute
 Independent
 570 employees
 R&D units:
- Biomass
- Solar energy
- Wind energy
- Energy Efficiency
- Policy studies
ECN and Torrefaction
 In 2002 ECN identified the potential of torrefaction
for bio-energy applications
 Present status:
Torrefaction
 ECN’s torrefaction technology is proven on pilotscale
 Demonstration and commercial market introduction
together with industrial partners
Pelletisation
Andritz/ECN Torrefaction Demo Plant Project
• 1 T/hr Torrefaction Demo Plant in Sdr. Stenderup, Denmark
• The plant incorporates:
• Biomass (Wood Chip) Receiving
• Biomass Drying
• Torrefaction
• Pelletizing
• Commissioning and initial testing phase scheduled for mid 2012
Pictures:
March
2012
Torrefaction technology – reactor concepts
Multiple hearth furnace
Torbed reactor
Rotary drum reactor
Oscillating belt reactor
Moving bed reactor
TurboDryer
Screw conveyor reactor
Microwave reactor
Bench-scale testing
5 kg/h Auger reactor
(screw reactor)
20 l batch reactor
Pre-drying
Feeding
Pilot-scale test facility PATRIG
Pilot-scale testing
 Testing history:
 Start-up 2008
 Over 1400 hours of operation (50-100 hour runs);
>40 tonnes of torrefied material produced
 Biomass feedstock: a.o. poplar, pine, wood
mixtures, forestry residues, agricultural residues
(POR)
 Conditions: 220-280 °C torgas inlet temp.,
throughput approx. 60 kg/h (input basis)
Characterisation of Torrefied biomass
Exothermicity
Self heating
11
19-3-2013
Pilot-scale torrefaction – results of typical run
Torrefaction reactor temperatures
300
Temperature (oC)
250
200
150
Mixture: poplar, spruce, birch and ash wood
27.8% moisture
Poplar chips 13.6% moisture
100
50
TOR_TIA2001L
0
15-03-10
0:00
15-03-10
12:00
16-03-10
0:00
16-03-10
12:00
17-03-10
0:00
TOR_TIA2001M
17-03-10
12:00
18-03-10
0:00
TOR_TIA2001O
18-03-10
12:00
19-03-10
0:00
TOR_TIA2252
19-03-10
12:00
20-03-10
0:00
Exothermicity – pilot scale
300
Temperature (°C)
290
L
280
M
270
N
260
T torr
250
Reactor
diameter
240
230
0
5
10
15
20
25
30
Position in tor-reactor (cm)
35
40
Example of temperature profile over the reactor diameter (biomass = softwood)
8
300
250
Temperature (°C)
utlet
Exothermicity – single particle
200
Ambient
Surface
Shifted middle
Middle
150
100
Torgas outlet
N2 inlet
50
8
Results from
single-particle
testing
N2 inlet
5
0
0
5
10
15
20
25
30
35
40
45
50
55
7
Time (min)
6
1. Thermal ceramic bricks
2. Screws
3. Glass sphere cut by the middle
4. Woody ball
5. Themocouples and their inlet
6. Gas inlet-outlet
7. Steel ball with double tube to act as inlet and outlet of gases
8. Gas heater
2
1
1
2
3
4
1. Thermal ceramic bricks
2. Screws
3. Glass sphere cut by the mi
4. Woody ball
5. Themocouples and their in
6. Gas inlet-outlet
7. Steel ball with double tube
8. Gas heater
Exothermicity – tests in batch reactor
Torrefaction of softwood with 2% O 2/98% N2
Torrefaction of softwood with 100% N2
300
300
250
250
98 % N2
2% O2 off
200
200
Average T bottom section
Average T middle section
150
Average T top section
T torr
temperature (°C)
temperature (°C)
100 % N2
off
Average T bottom section
Average T middle section
150
Average T top section
T torr
100
100
100 % N2
on
98 % N2
2% O2 on
50
50
0
0
0
10
20
30
40
50
60
time (min)
70
80
90
100
110
120
0
10
20
30
40
50
time (min)
Conclusion:
• 2% O₂ in the Torgas has significant effect on torrefaction process
• Temperature increase of > 30 °C measured in batch reactor
60
70
80
90
100
Exothermicity - summary
 Torrefaction reaction is exothermal
 Temperature profile in moving bed reactor
 Temperature increase depends on biomass type and O₂ in Torgas
 Temperature difference between particle centre and surface
 More research is needed to better understand the phenomenon
Self heating properties of torrefied biomass
• After torrefaction the torrefied
•
material must be exposed to air in a
controlled way
If not properly handled, spontaneous
combustion of torrefied materials
may arise
ECN, March 2008
Smoke – 24 Minutes
Fire – 32 Minutes
Self-heating properties
 Self-heating properties determined using Bowes-Cameron cage test as
described in the UN Recommendations on the Transport of Dangerous
Goods:
 Filled wire mesh cube placed in oven
 Oven temperatures 100, 120 or 140 °C
 If sample exceeds oven temp by 60 °C, than: self heating
 3 Samples tested: pellets from torrefied wood chips, EFB and OPF
Wood chips
Empty Fruit Bunches
Oil Palm Fronds
Self-heating properties
 Results:
 Crushed pellets from torrefied wood chips:
not classified as a self-heating substance
 Torrefied OPF pellets: not classified as a selfheating substance
 Torrefied EFB pellets: has self-heating
properties. Consequently, the material needs to
be classified as a self-heating substance
25/2/2012: Fire in Dutch torrefaction plant
Self heating??
Source: internet
Future research programme:
 Production of Solid Sustainable Energy Carriers from Biomass
by Means of TORrefaction
 EU FP7: Large-scale European project with 21 partners from
industry and science
EU FP7 project SECTOR
Biomass
Torrefaction
Densification
Logistics testing
End-use testing
Validated & optimised
solid bio-fuel
Research items
Shipment
Coal EF gasification
Storage & handling
Coal combustion
Grinding & feeding
Pelletburner
In conclusion
 Torrefaction development is in the pilot/demo-phase
 Scale-up, demonstration in partnership with Andritz Oy and Vattenfall
 Exothermicity and self heating are relevant issues in torrefaction
 Future research focuses on product quality (SECTOR)
 Research items:
 Optimizing the torrefaction and densification
processes towards product quality
 Self heating, storage, handling, biological
degradation
 Combustion, gasification
 Small and large scale testing
Thank you for your attention!
For more information,
please contact:
Fred Verhoeff
phone
e-mail
internet
+31 224 56 4510
[email protected]
www.ecn.nl
Production of tonne-scale test batches
at ECN for industrial trials
ECN
Westerduinweg 3
1755 LE Petten
The Netherlands
T +31 88 515 4949
F +31 88 515 8338
info@ ecn.nl
www.ecn.nl
8
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The Netherlands