Refractory Wear During Gasification
Larry Baxter1, Shrinivas Lokare1, Humberto Garcia2, Bing Liu1
1Brigham
Young University
Provo, UT
2Idaho
National Laboratory*
Idaho Falls, ID
Clearwater Coal Conference
Clearwater, FL
June 2, 2009
Gasification in the Literature
Number of Citable Papers
900
Total
800
Coal
700
Biomass
Natural Gas
600
Black Liquor
500
400
300
200
100
0
1970
1975
1980
1985
1990
1995
2000
2005
2010
Research by Country
3500
3000
2500
2000
1500
1000
500
0
Through 1995
Since 1995
Levelized Cost of Power
Fuel
VOM
FOM
Cap
TS&M
12
LCOE ¢/kWh
10
8
6
4
2
0
SC
USC
IGCC Amine Amine ASU
SC
USC
SC
ASU
USC
ITM
SC
IGCC
GE EnergyCryogenic
Radiant
Oxygen
Coal Slurry
63 wt.%
Coal
95% O2
Syngas
410°F, 800 Psia
Composition (Mole%):
Radiant Quench
H2
26%
Gasifier
CO
27%
2,500OF
Water
High
Pressure
Steam
Radiant
Syngas
Cooler
CO2
12%
H2O
34%
Other
1%
H2O/COSaturated
= 1.3
Syngas
398OF
1,100OF
Quench
Chamber
419OF
Syngas
Scrubber
Slag/Fines
Slag/Fines
Design: Pressurized, single-stage, downward firing,
entrained flow, slurry feed, oxygen blown,
slagging, radiant and quench cooling
Solids
To Acid Gas Removal
or
To Shift
ConocoPhillips E-Gas™
Syngas
Composition (Mole%):
H2
26%
CO
37%
CO2
14%
H2O
15%
CH4
4%
Other
4%
H2O/CO = 0.4
Stage 2
Coal Slurry
63 wt. %
Syngas
1,700°F, 614 psia
To Fire-tube
boiler
To Acid Gas Removal
or
To Shift
(0.22)
(0.78)
Char
Slag
Quench
95 % O2
Stage 1
2,500 oF
614 Psia
Slag/Water
Slurry
Design: Pressurized, two-stage, upward firing,
entrained flow, slurry feed, oxygen blown,
slagging, fire-tube boiling syngas cooling,
syngas recycle
Shell Gasification
HP Steam
Convective Cooler
Soot Quench
& Scrubber
Design: Pressurized, single-stage, downward firing,
slagging, entrained flow, dry feed, oxygen
blown, convective cooler
Gasifier
2,700 oF
615 psia
Syngas
Quench2
Syngas
350°F, 600 Psia
Steam
95% O2
HP
Steam
Dry
Coal
650 oF
Composition (Mole%):
H2
29%
CO
57%
CO2
2%
H2O
4%
Other
8%
H2O/CO = 0.1
To Acid Gas Removal
or
To Shift
Source: “The Shell Gasification Process”, Uhde, ThyssenKrupp Technologies
Slag
Transient Model Formulation
wall
… m…
M
123 … m …
M
2
n
gasifier
…
slag/ash
… m…
M
… m…
M
… m…
M
…
particle trajectory
Gas and Particle Flow Direction
1
N -1
N
Simulation – Gas Phase
1400
1300
Temperature / [°C]
1200
1100
1000
900
800
700
600
0
0,5
1
1,5
Axial Distance / [m]
2
2,5
3
Simulation – Gas Phase
0,6
CO(g)
CO2(g)
H2(g)
H2O(g)
H2S(g)
O2(g)
SO2(g)
SO3(g)
Mole Fraction
0,5
0,4
0,3
0,2
0,1
0
0
0,5
1
1,5
Axial Distance / [m]
2
2,5
3
Efficiency Calculation
Impaction Efficiency Improvement
Impaction Efficiency
100%
80%
60%
40%
Potential Flow
Viscous Flow
20%
Experiment
0%
0,1
1
10
100
1000
Stokes Number
(Stk )  1 b(Stk  a)1  c(Stk  a)2  d (Stk  a)3 
1
Potential Flow
Viscous Flow
a
0.1238
0.0868
b
1.34
1.9495
c
-0.034
-0.457877
d
0.0289
-0.047
Corrosion potential
Chlorides condensation is a major step in corrosion initiation
K
Si
Cl
S
Ca
Fe
Complex Inorganic Chemistry
Complex Inorganic Chemistry
Allen & Snow
Schuhmann & Ensio
Bowen & Schairer
Greig
1900
1700
2 Liquids
Cr
Liquid
1500
Fe2SiO4
Temperature /C
1928 ˚C
1300
Tr
1205 ˚C
1100
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Mole Fraction SiO 2
1
Al2O3-CaO-SiO2 Chemistry
1460
Liquid
o
Melting Point ( C)
1440
1420
1400
Solid
1380
1360
1340
0.2
0.3
CaO Weight Fraction
Al2O3/SiO2 = 0.34
0.4
Refractory-Slag Model
Syngas Tsyn
Forced Convection
Radiation
Steel Shell
Refractory
Deposited Ash
Slag
Air Tair
Free Convection
Radiation
Slag Importance
Corrosion Rate (mm/hr)
0.10
0.09
With Slag Flow
Without Slag Flow
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0.00
1300
1350
1400
1450
1500
o
Temperature ( C)
1550
1600
Refractory Wear with Time
0.0
0.2
1500hr
L (m)
500hr
0.4
1000hr
0.6
0.8
0.00
0.04
0.08
0.12
0.16
0.20
Refractory Wear Depth (m)
0.24
o
Melting Temperature ( C)
2000
Liquid Region
1800
Slag Cold-face Temperature
1600
1400
1200
Solid Region
1000
0.1
0.2
0.3
0.4
CaO Weight Fraction
0.5
0.6
Sensitivity to CaO content
Corrosion Rate (mm/hr)
0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
0.1
0.2
0.3
0.4
CaO Weight Fraction
0.5
0.6
Refractory Chemical Corrosion
0.007
0.006
Corrosion Rate (mm/hr)
2
0.1kg/m s
2
0.2kg/m s
0.005
0.004
0.003
0.002
0.001
0.000
1440
1460
1480
1500
o
Temperature ( C)
1520
1540
Spalling Mechanisms
Rel. Thermal Exp. Coef.
30
25
20
15
10
5
0
Refractory
Glass
Metal
Overall Refractory Wear
Chemical dissolution rates
depend in complex ways on
diffusivities, viscosities,
chemical reactions, and
temperature.
Spalling mechanisms and
rates are not well understood,
with quantitative models
being mostly empirical.
Net dissolution rates
disproportionately depend on
minor slag and refractory
components, involving
complex inorganic chemistry.
Spalling Mechanisms
Corrosion
Spalling
Spalling Mechanisms
1
6
4
5
2
3
Chemistry
(weight %)
Point
1
2
3
4
5
6
- Al
6.9
27.3
1.7
2.8
7.5
5.7
- Si
23.9
0.2
0.1
0.1
40.2
3.8
- Fe
20.8
31.7
23.6
0.2
1.5
0.5
- Ca
1.5
-
-
-
0.5
-
- Cr
0.1
1.5
42.7
62.1
1.5
53.0
Crystalline Phases
hercynite,
fayalite, enstatite,
Iron sulfide, iron
cordierite,
hermatite
iron-alumina
spinel
iron-chrome
spinel
Chromia/alumina
solid solution
Fe-depleted slag
Al build-up with Si
Refractory/Slag Profile
Distance
from
Hot
Face (mm)
Bulk Chemistry (wt pct)
X-Ray Crystalline
Phases
Cr2O3
Al2O3
SiO2
CaO
Fe
H.F. to 2.3
80.0
10.8
5.4
0.3
1.6
P= Cr2O3
Tr=M*Cr2O4
6.9
84.2
10.2
3.9
0.3
0.4
P= Cr2O3
Tr=M*Cr2O4
11.4
83.9
10.7
3.2
0.4
0.4
P= Cr2O3
Tr=M*Cr2O4
34.3
83.5
10.4
2.8
0.6
0.4
P= Cr2O3
43.3
83.9
9.3
2.3
0.5
0.2
P= Cr2O3
52.7
85.7
10.5
0.9
0.2
0.2
P= Cr2O3
57.2
86.1
10.5
0.2
0.0
0.2
P= Cr2O3
127
87.4
9.4
0.2
0.2
0.2
P= Cr2O3
Conclusions
• Chemical dissolution and spalling account for most
refractory wear.
• Both mechanisms depend on temperature,
slag/refractory composition, and slag flow rates,
approximately in that order.
• Temperature dependence arises from both transport
and solubility issues.
• Both immersion and spinning cup analyses provide
good corrosion information, but neither simulates
practical systems.
• Temperature, not peak deposition rates, determine
maximum corrosion location.
Acknowledgements
• PhD and post-doc students Shrinivas Lokare, Bing Liu
developed many of the submodels.
• Partial financial support from U.S. Department of
Energy contract DE-AC07-05ID14517 and from
corporate sponsors.