The document summarizes research on co-feeding fibrous biomass and coal into entrained flow gasifiers. It discusses the challenges of biomass as a fuel source and describes how torrefaction can be used as a pre-treatment step to improve biomass properties for gasification. It then outlines the Energy research Centre of the Netherlands' work in developing torrefaction technology, modeling slagging and fouling behavior, and testing biomass and coal mixtures using a lab-scale combustion simulator.

1. Co-Feeding Fibrous Biomass and Coal
into Entrained Flow Gasifiers
Robin Zwart
GAP & Coal Chemicals Conference
1 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

2. Presentation overview
Energy research Centre of the Netherlands (ECN)
 Short introduction to ECN
Entrained Flow Gasification
 General process flow scheme illustrating
the issues of co-feeding biomass
Photography by Jasper Lensselink
ECNs contribution to solving the issues
 Torrefaction technology development
 Quality control of the torrefied biomass
 Modelling slagging and fouling behaviour
 Simulating slagging and fouling behaviour
as well as testing reactivity
2 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

3. The Energy research Centre of the Netherlands
Mission of ECN
develop high-quality knowledge and technology for the
transition to sustainable energy management and
introduce this knowledge and technology to the market
Focus of ECN
- energy conservation
- sustainable energy by means of wind, solar and biomass
- efficient and clean use of fossil fuels
Technology development at ECN
- gasification and tar removal for production of CHP
- torrefaction as pre-treatment step for EF gasification
3 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

4. Entrained flow gasification
NUON Buggenum 250 MWe IGCC based on Shell EF gasification technology
4 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

5. Entrained flow gasification
Scheme from Roads2HyCom site (www.roads2hy.com) hosted by RWTH, Aachen, Germany
5 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

6. Torrefaction… as biomass is a difficult energy source
 … in view of:
 End-use (gasification, but also combustion and chemical processing)
 Logistics (feeding, as well as handling and transport)
 Difficult properties are:
 Low energy density (LHVar = 10-17 MJ/kg)
(LHVcoal > 30 MJ/kg)
 Hydrophilic
 Vulnerable to biodegradation
 Tenacious and fibrous (grinding difficult)
 Poor “flowability”
 Heterogeneous
6 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

7. Torrefaction…
for upgrading biomass
In short: the roasting of biomass
Gas
Dry Torrefied
biomass 0.3 0.1 biomass
1 Torrefaction 0.7
200-300°C Process parameters
1 0.9
 Temperature: 200-300°C
 Residence time: 10-30 minutes
0.9
Energy densification (MJ/kg) 1 = 1.3  Particle size: < 4 cm
0.7
 Absence of oxygen
mass energy  Pressure: near atmospheric
Lower temperatures than pyrolysis (i.e. less losses) & focusing on solid products!
7 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

8. Torrefaction
Woody biomass Agricultural residues
Friable and less fibrous Improved fuel properties:
19 - 22 MJ/kg (LHV, ar)
Hydrophobic  Transport, handling, storage
Preserved  Milling, feeding
Homogeneous  Gasification, combustion
 Broad feedstock range
 Commodity fuel
Mixed
waste
Tenacious and fibrous
Fuel powder
10 - 17 MJ/kg (LHV, ar)
Hydrophilic
Vulnerable to biodegradation
Heterogeneous Bulk density 650-750 kg/m3
Bulk energy density 13-17 GJ/m3 Fuel pellets
8 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

9. Torrefaction Air
Utillity fuel
The ECN BO2 technology Flue gas
 Conventional drying
and pelletisation Torrefaction
gas
 Compact dedicated Combustion
 moving bed technology
Gas
with direct heating recycle
(no moving parts)
Biomass BO2pellets
Pelletisation
Drying Torrefaction Cooling
 Heat integration
DP
 High energy
efficiency (> 90%) Flue gas
 Cost effective Heat exchange
Flue gas
 IP is patent protected
 Over 1,000 hours of
pilot scale production
9 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

10. Torrefaction
10 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

11. Quality control
Aiming for optimal…
 Heating value
 Overall energy efficiency
 Pellet durability
 Hydrophobicity
 Pellet density Temperature control to avoid hotspots and
 Grindability handle exothermic behaviour of the process
 Reactivity
Parameters available…
 Torrefaction temperature
(including good control)
 Torrefaction residence time
 Product cooling
 Densification procedure Temperature of torrefaction and densification
in order to reduce or avoid utilization of binders
11 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

12. Quality control Grindability
Torrefaction leads to a decrease in milling power required and increase in milling capacity
and as such allows co-feeding of biomass and coal in existing mills
12 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

13. Quality control Reactivity
Torrefaction material will convert faster than coal
and as such allows co-firing of biomass and coal in existing plants
13 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

14. Modelling slagging and fouling behaviour
FACTSage program for computational thermo chemistry
 Thermodynamic modeling used to investigate slagging behavior
and determine fluxing strategy for torrefied wood types
 Investigate potential fate of inorganic components as function of
gasification temperature
 Measure ash fusion temperatures of mixtures of coal/torrefied
wood/fluxing agent
 Determine the ideal mixture of biomass and coal which will
results in better performance than coal or biomass alone
14 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

15. Modelling slagging and fouling behaviour
Phase distribution (example 1300°C)
15 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

16. Modelling slagging and fouling behaviour
Alkali distribution
16 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

17. Modelling slagging and fouling behaviour
Slagging behavior as function ofelements in biomass for fluxed clean wood fuel
wt% ash mixing slag as f(T) and coal
wt% ash elements in slag as f(T) for fluxed clean wood fuel
100
100
90
slag as wt% of fuel ash (incl. flux)
90
slag as wt% of fuel ash (incl. flux)
Original clean wood
80
80
70
70 Silica/fuel ash=0.25 kg/kg
60
60
50
Silica/fuel ash=0.75 kg/kg
50 40
40 30 Silica/fuel ash=1.25 kg/kg
30 20
20 10 Silica/alumina/fuel
10 0 ash=0.5/0.45 kg/kg
0 800 1000 1200 1400 1600 18
800 1000 1200 1400 1600 1800 T [°C]
T [°C]
17 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

18. Labscale Combustion & gasification simulator (LCS)
Residence time/temperature profile (example)
LCS PF facility (controlled conditions, 5 ms up
to 2500ms, 600-1550°C, gas composition)
Temperature [°C]
1000 1200 1400 1600
0 20
90
0,1
0,2 Burner Area
0,3 210
Residence time [ms]
Distance [m] 0,4
0,5
0,6
0,7
1300
0,8
0,9
Furnace Exit
1
18 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

19. Labscale Combustion &
gasification simulator (LCS)
LCS gasification experiments investigating:
 Conversion
 Slagging behavior
 Particle sintering on top syngas cooler (800-850°C)
 Particle deposition in economizer (400-600°C)
 Particle sampling (fate of inorganic components)
 Analysis of all samples
19 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

20. Lab-scale Combustion Simulator (LCS)
Lab-scale facility to mimic pulverised-fuel combustion
and high-temperature gasification conditions
Staged gas
burner: high
heating rate +
proper gas
atmosphere
Special reactor design:
Particle
1-2s residence times
sampling
with only limited total
Fouling probe probe
reactor length
20 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

21. Labscale Combustion & gasification simulator (LCS)
Fouling
Investigate fouling:
 Transfer duct
 Influence on heat
transfer
heat flux sensor deposit ring
21 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

22. Labscale Combustion & gasification simulator (LCS)
Deposition (example 1300°C) Wood, no additive
Wood, Si additive
22 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

23. Labscale Combustion & gasification simulator (LCS)
Deposition (example 600°C) Straw, with kaoline
as additive
Close-up
KCl
23 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

24. Labscale Combustion & gasification simulator (LCS)
Particle sampling
 Oil-cooled
 Gas quench (N2 or He)
 Cyclone/filter/cascade
impactor for particle
sampling
wood, Si additive
gas/ash
quench
24 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing

25. Labscale Combustion &
gasification simulator (LCS)
Particle sampling
Fractionated samples (lab- & full-scale)
obtained with cascade impactors (CI):
 Study release inorganics and
aerosol formation
 Provides composition and
morphology of each size 70
fraction 60
plate
stage 1
stage 2
 In short: particle sampling
stage 3
weight fraction [% w/w]
50 stage 4
stage 5
allows investigation of 40 stage 6
stage 7
stage 8
all inorganic particles that 30 stage 9
stage 10
enter syngas cooler 20
10
0
25 GAP & Coal Chemicals Conference 8-9 June 2011 - Fe
S Beijing
Na Mg Al Si P Cl K Ca

26. Thank you for your attention...
For more information,
please contact:
Robin Zwart
phone +31 224 56 4574
mobile +31 6 3073 6496
e-mail zwart@ecn.nl
internet www.ecn.nl
26 GAP & Coal Chemicals Conference 8-9 June 2011 - Beijing