Safe co-combustion and extended use of biomass
and biowaste in FB’s with accepted emissions
ENK5-CT2002-00638 1.1.2003-31.12.2005
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Background
C o n tr o lle d
E m is s io n s
N E W C O -IN C IN E R A T IO N
D IR E C T IV E
O F T H E C O M M IS S IO N
S a fe
c o m b u s t io n
p ro c e s s
in F B
E f f ic ie n t
m o n it o r in g
a n d e m is s io n
c o n tro l
TOOLS
• C o m b u s ti o n
re a c to rs
• A d v a n c e d o n -lin e
a n a ly s e rs
•M o d e llin g
TOO LS
• C o m b u s tio n
re a c to rs
• A d v a n c e d o n - lin e
a n a ly s e r s
• M o d e llin g
L a n d f ill
C O M B U S T IB L E W A S T E
In d u s tr ia l w a s te
H o u s e h o ld w a s te
A g r ic u lt u r a l w a s t e
M ad cow
VTT PROCESSES
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Partnership (VTT Co-ordinated)
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1. Technical Research Centre of Finland, Processes FIN
2. Kvaerner Power OY FIN
3. Offenbach Power Company GER
4. Dekati Measurements OY FIN
5. Institute of Process Engineering and Power Plant Technology,
University of Stuttgart GER
6. Technical University Wroclaw (<-> Turow) PL
7. Emissions-Reduzierungs-Concepte GmbH GER
8. Thermal Power Engineering, Technishe Universiteit Delft NL
9. W.K. Crone B.V. NL
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Workpackages (EU funding 1,5 million €)
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WP1 “ Fuel delivery, treatment and analysis” responsible partner 1
WP2 “Creating basis to replace part of brown coal with biomass waste in large
Polish CFB plants”, responsible partner 5
WP3 “Creating basis to replace higher share of coal with MBM in a CFB plant”
responsible partner 1
WP4 “Improving calculation tools and biomass fuel flexibility in small BFB plants for
Eastern European markets responsible partner 8
WP5 “Combustion problem solution by chemicals” responsible partner 7
WP6 “Means to reach high share of household waste in FB’s and developing an
alarm sensor of corrosive flue gases for FB combustion” responsible partner 1
WP7 “Management, implementation, reporting” responsible partner 1
VTT PROCESSES
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
WP3
Selection of MBM and
coals, OPC
0.1 MW CFB exp.
VTT
’
Best coal
for MBM
Tests in 100 MW CFB
OPC
Basis to find
synergic effects
Solution of operational and emission
problems to 25% MBM
MBM: 15->25% enb
Guidelines
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Thermal power plant
CIRCOFLUID®
Offenbach
Thermal power plant
Year of Commissioning
1988
Thermal Capacity
80
MW
Live Steam
110
t/h
535
°C
115
bar
Feedwater
191
°C
Min. Load
40
%
VTT PROCESSES
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
WP3 Location of superteaters in the 80 MW CFB (Babcock)
SH1
SH2
SH3
VTT PROCESSES
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
Problems were detected in EVO´s CFB when
MBM was co-fired with German coal
Experiments in VTT´s 0.1 MW CFB reactor
assisted in the solution of detected problems
in the CFB boiler
High superheater corrosion
rate
Strong fouling
EVO AG´s 100 MWth CFB
VTT´s 0.1 MWth CFB
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Elemental concentrations of selected damaged parts of the
CFB plant superheaters D= deposition C= corrosion
contributor
35
D
30
25
UE2-1
UE2-2
UE3-1
UE3-2
C
%
20
15
10
5
0
C
VTT PROCESSES
Na
Mg
Al
Si
P
S
Cl
K
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
Ca
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Theory
Alkali chlorides in the furnace can be destroyed by two reactions
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2MCl + SO2 + ½ O2 + H2O -> M2SO4 + 2 HCl (1) (better known)
* 2 MCl + Al2O3*2SiO2 + H2O -> M2O*Al2O3*2SiO2 + 2HCl (2) (new)
* Coal can be used as a source of sulphur and aluminium silicates!
VTT PROCESSES
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
K 2O
Composition of ash obtained at 550 C
100 %
90 %
70 %
K2O
60 %
P2O5
FeO
50 %
CaO
40 %
SiO2
30 %
Al2O3
20 %
10 %
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M
10
0
40
M
60
PC
30
M
70
PC
10
0P
C
40
M
60
SA
30
M
70
SA
20
M
80
SA
SA
10
0
M
60
G
C4
0M
30
G
C
70
80
G
C
20
G
M
C
0%
10
0
% wt, in ash
80 %
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Fuel composition, wt dry basis
100 GC
18.00 %
80 GC 20 M
16.00 %
70 GC 30 M
Coals
14.00 %
60GC40M
100 SA
12.00 %
80SA20M
10.00 %
70SA30M
8.00 %
60SA40M
100PC
6.00 %
70PC30M
4.00 %
60PC40M
2.00 %
0.00 %
Ash 815 °C
VTT PROCESSES
Cl (x10)
S (x10)
K (x10)
Na (x10)
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Deposit probing from 0.1 MW CFB -> SEM analysis in Åbo Akademi
University
Lee
side
50o from Wind
side
β=50°
Wind
side
Inorganic
vapors
VTT PROCESSES
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
0.1 MW CFB: 420 oC 50 o up
60% GC
60% SA coal
30
60 SA
60% PC
60 PC
25
60 GC
80G C20M
20
70G C30M
wt%
60G C40M
70S AC30M
15
60S AC40M
100P C
70P C30M
10
60P C40M
5
0
Cl
VTT PROCESSES
K
Na
Al
Si
S
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Problem solution
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Advice: Please, change German coal to South Afrcan coal!
Problem in German coal: High potassium contents incactivates the
protective compounds in the coal ash
Advantage in S.A. coal: Rich in active aluminium silicate destroying
alkali chlorides before their deposition
Alkali aluminium silicate dominates strongly over sulphation in
alkali capture (leading to HCl formation)
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
CASE: GERMAN COAL AND MBM COFIRING
Heat transfer
surface
Y CO M P O UND
ALKALI
CHLORIDES
S
RI
SK
Cl releases
Ê corrosion
K-inhibited
protecting
compounds
Low ash
content
MBM
VTT PROCESSES
GERMAN COAL/
LESS PROTECTIVE COAL
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
WP6
Selection of househ.w, bark,
coal: KPOY
0.02 MW BFB VTT
2 MW BFB KPOY
Sensor
testing
Dekati M
Scale-up
0.1 MW CFB VTT
’
4 MW CFB KPOY
Scale-up
Sensor
Sensor development (Na,K, Cl)
Dekati M
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
Guidelines
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
VTT:s contribution in WP6:
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Experiments with mixtures of different coals and RDF
RDF received as pellets from Pietarsaari
Goas:
- To find means to prevent Cl deposition
- To get more infotrmation on Cl deposition
(together with Kvaerner Power)
- To get more information on mechanisms presenting Cl deposition
(in co-operation with Kvaerner Power)
- To participate to scale-up together with Kvaerner power
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RDF contained 0.65 wt% chlorine and 9 wt% ash
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Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
30.0
25.0
Working
methodology
500ºC wind
Deposit
sampling
wt% Cl
20.0
500ºC lee
500ºC 50º
420ºC wind
15.0
420ºC lee
420ºC 50º
10.0
5.0
Flue
gas
analysis
0.0
40SAC60RDF
38PC62RDF
40RDF60B
SEM EDS
Fine fly ash share
Tacky
deposit
Particle
analysis
Inorganic
vapors
600
<4.02 µm
In HCl
Cl mg/Nm3
500
400
300
200
Fine fly ash
sampling
Particle
analysis
250
200
Cl mg/Nm3
700
100
0
VTT PROCESSES
1.61-4.02 µm
0.64-1.61 µm
0.26-0.64 µm
0.1-0.26 µm
0.03-0.1 µm
150
100
50
40SAC60RDF
38PC62RDF
40RDF60B
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
0
40SAC60RDF
38PC62RDF
40RDF60B
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Dependency between risky chlorine flow (in the fly ash)
and Cl deposition
700
30.0
600
25.0
<4.02 µm
In HCl
400
500ºCwind
20.0
wt% Cl
Cl mg/Nm3
500
300
500ºClee
500ºC50º
420ºCwind
15.0
420ºClee
420ºC50º
10.0
200
100
5.0
0
0.0
40SAC60RDF
38PC62RDF
40RDF60B
40SAC60RDF
38PC62RDF
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
VTT PROCESSES
40RDF60B
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Distribution of chlorine and potassium in fine fly ash
Cl
K
250
160
140
200
1.61-4.02 µm
0.64-1.61 µm
0.26-0.64 µm
0.1-0.26 µm
0.03-0.1 µm
150
100
50
K mg/Nm3
Cl mg/Nm3
120
1.61-4.02 µm
0.64-1.61 µm
0.26-0.64 µm
0.1-0.26 µm
0.03-0.1 µm
100
80
60
40
20
0
40SAC60RDF
38PC62RDF
40RDF60B
0
40SAC60RDF
VTT PROCESSES
38PC62RDF
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
40RDF60B
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Distribution of chlorine and sulphur in fine fly ash
Cl
S
250
25
20
1.61-4.02µm
0.64-1.61µm
0.26-0.64µm
0.1-0.26µm
0.03-0.1µm
150
100
50
S mg/Nm3
Cl mg/Nm3
200
1.61-4.02 µm
0.64-1.61 µm
0.26-0.64 µm
0.1-0.26 µm
0.03-0.1 µm
15
10
5
0
0
40SAC60RDF
38PC62RDF
40RDF60B
40SAC60RDF
38PC62RDF
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
VTT PROCESSES
40RDF60B
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Hiukkasten massavirta kerrostumanäytteenottimen
kohdalla
Seos: kuori 60 RDF 40
1400
1400
1200
1200
dm/dlog(Dp) [mg/Nm³]
dm/dlog(Dp) [mg/Nm³]
Seos: SA coal 40 RDF 60
1000
800
600
400
0.1
1
Particle Diameter Dp [µm]
VTT PROCESSES
800
600
Tiivistyneitä
alkali
klorideja
400
200
200
0
0.01
1000
10
0
0.01
0.1
1
Particle Diameter Dp [µm]
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Esimerkki lentotuhkan raskasmetallipitoisuuksista
(Direktiivin summattavat metallit)
60PC40RDF metals
60SAC40RDF metals
0.6
0.6
<0.2
0.2 to 1
1 to 8
0.4
0.5
wt% in ash fraction
wt% in ash fraction
0.5
0.3
0.2
<0.2
0.2 to 1
1 to 8
0.4
0.3
0.2
0.1
0.1
0
0
Mn
Pb
Cr
VTT PROCESSES
Ni
Cu
Co
As
Sb
V
Mn
Pb
Cr
Ni
Cu
Co
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi
As
Sb
V
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Sum metals in dust (Mn+Pb+Co+Cr+V+Ni+As+Sb+Cu)
9,0
8,0
Fly ash particle size
7,0
Total metal emission limit=0.5 mg/Nm3
mg/Nm3
6,0
1 to 8 µm
Measured metal emission
5,0
4,0
0.2 to 1µm
3,0
<0.2
2,0
1,0
VTT PROCESSES
F
40
RD
60
SA
80
SA
20
RD
F
F
40
RD
60
PC
F2
0B
40
RD
40
PC
10
0D
W
0,0
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Conclusions
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RDF share can be rised up to 60% on energy basis without Cl
deposition when co-fired with an with optimal coal
Again: Optimal coal is rich with free aluminium silicate
Sulphation was not clearly observed as a mechanism to destroy
alkali chlorides
New working methodology for Cl deposition study (impactor
sampling from hot furnace is very demanding stage)
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
List of publications
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WP3: Aho, M. and Ferrer. E., Importance of coal ash composition in protecting the
boiler against chlorine deposition during combustion of chlorine-rich biomass. Fuel
84 (2005) 201-212
WP3: Ferrer, E., Aho, M., and Filipczyk, D., Solution of Superheater Related
Problems in CFB During Co-Firing of a Demanding Biomass Residue by Coal
Quality Optimisation.
In the proceedings of VGB Workshop "Operating Experience with Fluidised Bed
Firing Systems 2004”. VGB Power Tech, Berlin, September 22-24. 17 p.
WP6: Aho, M., and Silvennoinen, J., Preventing Chlorine Deposition on heat
Transfer Surfaces with Aluminium-Silicon Rich Biomass. Fuel 83 (2004) 1299-1305
WP6: Silvennoinen, J., Roppo, J., Nurminen, R.V., Aho, M., Vainikka, P., Ferrer, E.,
Co-combustion of coal, RDF and biomass- Prevention of chlorine deposition by
using coal ash absorption ability. Proceedings of 18th international Conference of
FB combustion. Toronto, Canada May 22-25, 2005.
WP6: Ferrer, E., Aho, M., Silvennoinen, J. and Nurminen R.V. FB Combustion of
refuse-derived fuel (RDF) at large portions with presence of protective coal. Fuel
Processing Technology 87 (2005) 33-44.
WP6: Aho, M., Vainikka, P., Taipale, R., and Vesala, H., Alkali Chloride deposition
problem solution with protecting fuel and simultaneous measurements with
impactors, FTIR and deposit probes. In proceedings of 14th European Biomass
Conference & Exhibition 17-21 October 2005, Paris, France 5p.
PhD Thesis:
WP’s 3 and 6: Academic dissertation of Mr. Eduardo Ferrer will be arranged in the
University of Zaragoza, Spain in 2006.
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Staff in VTT
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Operators: Kimmo Roiha & Kimmo Puolamäki, Pertti Frilander
FB developing engineer: Kari Paakkinen
Researchers: Martti Aho, Eduardo Ferrer, Raili Taipale, Pasi
Vainikka from VTT Jyväskylä, Hannu Vesala from VTT Espoo
Acknowdeglements:
* European Commission for funding 50% of VTT’s costs
* TEKES for funding 20% of VTT’s costs
* Åbo Akademi/ Proces Chemistry for conducting deposit analysis
VTT PROCESSES
Martti Aho/ II Liekki-päivä 24.1.2006 Åbo Akademi