FINNISH-SWEDISH FLAME DAYS 2009-01-28
Gas Phase Reaction Schemes for Black Liquor
Gasification Modeling
Per Carlsson*, Magnus Marklund, Henrik Wiinikka, Rikard Gebart
*Corresponding author
per.carlsson@etcpitea.se
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Kraft pulp mill of today
Smurfit Kappa Kraftliner, Piteå
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Black Liquor
Proximate matter
Moisture
Volatile matter
Fixed carbon
Smelt (ash)
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%wt
30
30
8
32
3
Black Liquor Gasification DP-1
SHORT TIME
CONTACTORS
BLACK LIQUOR
OXYGEN AND
ATOMIZING MEDIA
COOLING
WATER
GAS COOLER
WHITE
LIQUOR
REACTOR
RAW
GAS
QUENCH
CLEAN, COOL
SYNTHESIS
GAS
GREEN
LIQUOR
CONDENSATE
WEAK
WASH
Courtesy of Chemrec AB
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Conversion in the reactor
BLACK LIQUOR
OXYGEN AND
ATOMIZING MEDIA
Drying
Devolatilization
Char gasification
Smelt formation
Synthesis gas and smelt
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Model
Ansys CFX 11 with Fortran sub routines
The model includes drying, pyrolysis, char gasification and smelt
formation of black liquor droplets as well as a simplified gas
phase reaction scheme.
Black liquor particles modeled using the Euler – Lagrange
formulation
k– turbulence model with standard wall functions
Discrete transfer radiation model
Eddy dissipation model/Finite rate chemistry
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Gas sampling in the reactor
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Results, dry gas composition
Specie
Simulated results 4R
Probe gas composition (%mole)
Reactor measurements
Probe gas composition (%mole)
CO
34.7
27.6 ± 0.83
CO2
24.0
33.7 ± 0.46
CH4
0.0
1.2 ± 0.05
H2
39.2
36.2 ± 0.71
H2S
2.0
1.3 ± 0.05
F C conversion
99.8%
~100% estimate
CO / CO2
1.45
0.82
CH 4
CH 4
H2
1
O2
2
H 2O
1
O2
2
CO H 2O
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CO 2 H 2
CO 3H 2
H 2O
CO2 H 2
8
Entrainment of hot gases to the oxygen rich zone
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Results, dry gas composition
Specie
Simulated results 4R
Probe gas composition (%mole)
Simulated results 5R
Probe gas composition (%mole)
CO
34.7
35.1
CO2
24.0
23.8
CH4
0.0
0.0
H2
39.2
39.1
H2S
2.0
2.0
F C conversion
99.8%
99.9%
CO / CO2
1.45
1.47
CH 4
CH4
H2
1
O2
2
H 2O
1
O2
2
CO H 2O
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CO 2 H 2
CH 4
CO 3H2
CH 4
H 2O
CO2 H 2
1
O2
2
H 2O
CO 2H 2
CO 3H 2
1
O2
H 2O
2
1
CO
O2
CO2
2
CO H 2O CO2 H 2
H2
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Results, temperature
Case
4R
5R
Peak
2337 K
3121 K
Volume average
1321 K
1347 K
Sampling point
1345 K
1365 K
Reactor outlet
1342 K
1363 K
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Discussion
Case
4R
5R
DP-1
Sampling point
temperature
1345 K
1365 K
-
CO / CO2
1.45
1.47
0.82
CO H 2O
CO2 H 2
Reactor wall losses not included into the model
Backward reaction not included for all reactions
Black liquor dry substance overestimated with standard method
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Conclusions
Peak temperature was increased significantly by implementing the
CO + ½O2
CO2 reaction.
Effects on volume average and outlet gas temperature was small
when implementing the CO + ½O2 CO2 reaction.
The CO + ½O2 CO2 reaction had very small effect on outlet gas
composition when used with the Jones – Lindstedt simplified
reaction scheme.
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Future work
Gas temperature measurements
Wall heat loss influence
Black liquor characterization
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Acknowledgment
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Questions
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