Effects of Oxygen Concentration and
Coal Composition on Aerosol Chemistry
in Oxy Firing
William J. Morris
Dunxi Yu
Jost O. L. Wendt
Department of Chemical Engineering
University of Utah, Salt Lake City, UT 84112
2010 AIChE Annual Meeting
Salt Lake City, Utah
November 7-12, 2010
Outline
•
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Objectives
Coals examined
Furnace, sampling, and analysis
Results
Conclusions
Objectives
• Provide a comparison of three different coal aerosols
under two different oxy fired scenarios for predicting
effects of coal composition on oxy firing.
• Examine aerosol chemistry under two different oxy
fired scenarios: 27% O2 (~match heat flux of air) and
32% O2 (~match adiabatic flame temperature of air).
• Use aerosol chemistry to provide information for those
who wish to make predictions of fouling/slagging
within the furnace.
• Determine whether there are any significant
differences in aerosol chemistry at varying O2
concentrations at conventional temperatures.
Coal Chemistry
Coal Analysis (on an as-received basis)
Sample
Volatile Fixed
HHV
Matter Carbon BTU/lb
LOD
Ash
C
H
N
S
O (diff)
%
%
%
%
%
%
%
%
%
Utah
3.18
8.83
70.60
5.41
1.42
0.53
13.21
38.60
49.39
12606
PRB
23.69
4.94
53.72
6.22
0.78
0.23
34.11
33.36
38.01
9078
Illinois
9.65
7.99
64.67
5.59
1.12
3.98
16.65
36.78
45.58
11598
K
as K2O
Si
as SiO2
Na
as Na2O
S
as SO3
Ti
As
TiO2
Ash Analysis
Al
as
Al2O3
Ca
as CaO
Fe
as
Fe2O3
%
%
%
%
%
%
%
%
%
%
%
Utah
14.52
6.11
5.09
1.39
0.02
0.59
0.57
60.89
1.41
2.33
0.88
PRB
14.78
22.19
5.2
5.17
0.01
1.07
0.35
30.46
1.94
8.83
1.3
Illinois
17.66
1.87
14.57
0.98
0.02
0.11
2.26
49.28
1.51
2.22
0.85
Mg
Mn
P
as MgO as MnO as P2O5
Coal Firing Rates and Combustion
Conditions
Coal
Coal feed rate (kg/h)
Utah Skyline
4.50
PRB
6.26
Illinois Bituminous
4.89
Combustion
Mode
Oxidant
Composition
Coal firing rate (kW)
36.64
Practical Significance
OXY27
Oxyfuel
27%O2/73%CO2
Combustion
OXY32
Oxyfuel
32%O2/68%CO2 Match AIR adiabatic flame temperature
Combustion
Match AIR gas radiant heat flux
Sampling Systems
Laboratory Combustor
Coal feeder
Primary
Secondary
1.2 m
3.8 m
1. Maximum capacity: 100 kW
2. Representative of full scale units:
1. Self sustaining combustion
2. Similar residence times and
temperatures
3. Similar particle and flue gas
species concentrations
3. Allows systematic variation of
operational parameters
Heat exchanger #1 - 8
Sampling port
Flue gas
This work: Uses once-through
CO2 to simulate cleaned flue
gas recycle with all
contaminants and water
removed.
Future work: Will use recycled
flue gas.
Analysis
• Samples were collected with a Berner low
pressure impactor.
• Size segregated samples were then analyzed
using ICP-MS.
• Due to the difference in flue gas volume (m3)
of OXY27 and OXY32 conditions, results were
also normalized to ug per g of coal burned.
Results
Utah Skyline OXY27
1000000.00
dM/dlogDp (ug/m3)
100000.00
Na2O
MgO
10000.00
Al2O3
1000.00
SiO2
P2O5
100.00
K2O
CaO
10.00
TiO2
1.00
MnO
Fe2O3
0.10
As2O3
SeO2
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Utah Skyline OXY32
1000000.00
dM/dlogDp (ug/m3)
100000.00
Na2O
MgO
10000.00
Al2O3
1000.00
SiO2
P2O5
100.00
K2O
CaO
10.00
TiO2
1.00
MnO
Fe2O3
0.10
As2O3
SeO2
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB OXY27
1000000.00
dM/dlogDp (ug/m3)
100000.00
Na2O
MgO
10000.00
Al2O3
1000.00
SiO2
P2O5
100.00
K2O
CaO
10.00
TiO2
1.00
MnO
Fe2O3
0.10
As2O3
SeO2
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB OXY32
1000000.00
dM/dlogDp (ug/m3)
100000.00
Na2O
MgO
10000.00
Al2O3
1000.00
SiO2
P2O5
100.00
K2O
CaO
10.00
TiO2
1.00
MnO
Fe2O3
0.10
As2O3
SeO2
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois OXY27
1000000.00
dM/dlogDp (ug/m3)
100000.00
Na2O
MgO
10000.00
Al2O3
1000.00
SiO2
P2O5
100.00
K2O
CaO
10.00
TiO2
1.00
MnO
Fe2O3
0.10
As2O3
SeO2
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois OXY32
1000000.00
dM/dlogDp (ug/m3)
100000.00
Na2O
MgO
10000.00
Al2O3
1000.00
SiO2
P2O5
100.00
K2O
CaO
10.00
TiO2
1.00
MnO
Fe2O3
0.10
As2O3
SeO2
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Utah Fe2O3
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
Utah OXY27 Fe
Utah OXY32 Fe
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB Fe2O3
dM/dlogDp (ug/g coal)
1000.00
100.00
PRB OXY27 Fe
PRB OXY32 Fe
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois Fe2O3
dM/dlogDp (ug/g coal)
1000.00
100.00
Ill OXY27 Fe
Ill OXY32 Fe
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Utah CaO
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
Utah OXY27 CaO
Utah OXY32 CaO
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB CaO
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
PRB OXY27 CaO
PRB OXY32 CaO
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois CaO
dM/dlogDp (ug/g coal)
100.00
10.00
Ill OXY27 CaO
Ill OXY32 CaO
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Utah Na2O
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
Utah OXY27 Na2O
Utah OXY32 Na2O
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB Na2O
dM/dlogDp (ug/g coal)
1000.00
100.00
PRB OXY27 Na2O
PRB OXY32 Na2O
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois SiO2
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
Ill OXY27 SiO2
Ill OXY32 SiO2
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Utah SiO2
dM/dlogDp (ug/g coal)
100000.00
10000.00
1000.00
Utah OXY27 SiO2
100.00
Utah OXY32 SiO2
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB SiO2
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
PRB OXY27 SiO2
PRB OXY32 SiO2
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois SiO2
dM/dlogDp (ug/g coal)
10000.00
1000.00
100.00
Ill OXY27 SiO2
Ill OXY32 SiO2
10.00
1.00
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
PRB As2O3
dM/dlogDp (ug/g coal)
1.00
0.10
PRB OXY27 As2O3
PRB OXY32 AsO3
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois As2O3
dM/dlogDp (ug/g coal)
10.00
1.00
Ill OXY27 As2O3
Ill OXY32 As2O3
0.10
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Utah SeO2
dM/dlogDp (ug/g coal)
100.00
10.00
1.00
Utah OXY27 SeO2
Utah OXY32 SeO2
0.10
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Results
Illinois SeO2
dM/dlogDp (ug/g coal)
10.00
1.00
Ill OXY27 SeO2
Ill OXY32 SeO2
0.10
0.01
0.01
0.1
1
Aerodynamic Particle Diameter (um)
10
Conclusions
• Fine fragmentation mode (~1 um) is not
affected by small changes in PO2 at
conventional temperatures.
• Coal composition still plays the dominant role
in aerosol chemistry.
• Only differences are noticed in the ultra-fine
region <100nm. This is the condensed vapor
phase mode and is likely due to a hotter flame
temperature yielding increased vaporization.
Acknowledgements
• Financial support from the Department of Energy
under Awards DE-FC26-06NT42808 and DE-FC08NT0005015
• David Wagner, Ryan Okerlund, Brian Nelson,
Rafael Erickson, and Colby Ashcroft Institute for
Clean and Secure Energy, University of Utah
• Diego Fernandez and his team of analytical
chemists in the Department of Geology and
Geophysics, University of Utah