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Combustion Optimization for Decreased Emissions and
Improved Efficiency
J. Estrada, Progress EnergySt. Petersburg, FL
D. Earley, Combustion TechnologiesApex, NC
B. Kirkenir, Progress EnergyRaleigh, NC
AcknowledgementsBob Sisson
Crystal River Plant Engineer
Crystal River Power PlantCrystal River, FL
Ideal Furnace CombustionProper and even burner stoichiometry leads to
consistent flames in furnaceFuel:Air ratio distribution
Emissions reduction and improved efficiency Low hanging fruitPotential alternative to post combustion
emission equipment
Crystal River Unit 4B&W Opposed Fire Pulverized Coal 770 MW
6 MPS-89 Puvlerizers 9 Coal Outlets per Mill
54 B&W DRB-4Z Low NOx Burners
6 Compartmentalized Windboxes3 x Front, 3 X Rear
SCR, Cold Side ESP & Wet FGD
Continuous Combustion Management (CCM)
Equipment Additions:Coal Flow Measurement & control valvesBurner Secondary Air Flow Measurement & auto
purgeBurner Secondary Air Flow AdjustmentPrimary Air Measurement and Auto PurgeCO measurement
Equipment ModificationsRelocation of O2 ProbesNew O2 equipment (probes and cabinets)
Coal BalancingProblem: Uneven Coal distributionSolution: Online coal measurement +
adjustment
Coal Out
Coal In
Pulverizer Discharge
Adjustable Coal Valves
Coal Flow MeasurementAir Monitor Corporation
Santa Rosa, CA
Coal Flow Balancing
Coal Flow Balancing
Burner Air:Fuel Ratios
Secondary Air Balance
Secondary Air
Secondary Air
•Problem: Uneven Secondary Air (SA) distribution
•Solution: Measure SA flow at each burner and adjust SA dampers
Windbox Air Dampers
Windbox Air Dampers
Secondary Air MeasurementWind Tunnel Testing at Air Monitor HQ
Why Automate SA Dampers?Dynamic windbox flow profiles
Fluctuating windbox pressureAsh build-up
Burner1
Burner2
Burner3
Post-CombustionCO and O2 measurement accuracy is criticalGrid configuration preferred
Op
tim
um
Zo
ne
Op
tim
um
Zo
ne Boiler Efficiency
Air Flow
Co
mb
us
tio
n P
ara
me
ters
CO
O2
NOx
LOI
Co
mfo
rt
Zo
ne
Co
mfo
rt
Zo
ne
Slagging
Fireside Corrosion
Tube Leaks
O2 Probe Relocation
Old location not representative of furnace O2 profile
Economizer
ECONOMIZER ASH HOPPER
FLUE GAS
CASCADE ROOM
OLD O2 LOCATION
NEW O2 LOCATION 15
'
40'
New location proven to be more accurate through testing with B&W
Significant distribution improvement realized due to new location
O2 Probe Standard Deviation
0
1
2
3
4
5
6
7
8
0 100 200 300 400 500 600 700 800 900
Stan
ard
Dev
iati
on(P
robe
s 2 &
7 O
mitt
ed)
Gross Load (MW)
CR4 O2 Probe Standard Deviation
Pre-Outage
Pre-Tuning
Post Tuning
CRN O2 Distribution ComparisonsCR4 O2 Profiles
CR5 O2 Profiles
Note: Unit scales are different
CO Probe AugmentationCO is better diagnostic tool than O2 alone
Air leakage impact on O2 probe
CCM Tuning
-2
-1
0
1
2
3
4
5
6
0
100
200
300
400
500
600
700
800
900
1000
06
/09
/10
06
/11
/10
06
/13
/10
06
/15
/10
06
/17
/10
06
/19
/10
06
/21
/10
06
/23
/10
06
/25
/10
06
/27
/10
06
/29
/10
PercentPPM
CR4 Load > 700 MW
North CO Avg
South CO Avg
SCR In Nox North
SCR In Nox South
O2 ANALYZER (SEL)
Daily LOI
CCM Tuning
Remote Combustion Dashboard
New O2 CurveLOI benefit
0.0%
1.0%
2.0%
3.0%
4.0%
5.0%
6.0%
7.0%
8.0%
9.0%
10.0%
0 1000 2000 3000 4000 5000 6000
Exce
ss O
2 (%
)
Steam Flow (kpph)
Unit 4 O2 Curve
Old Curve
Manual Curve
New Curve
NOx Benefit
Project ResultsBoiler Efficiency Increase = 0.5%
Annual fuel savings
Combustion NOx Reduction7% at full load, 15-25% at part loadAnnual Ammonia Reagent Usage ReductionSCR Catalyst Life Extension
Fan Auxiliary Power Savings
Pre vs. Post CCM Boiler Efficiency Comparisons
Operational DescriptionBase -- Original OEM Predicted
Efficiency Pre CCM Test w/ 2.5 lb Sulfur Coal Post CCM Test w/ 2.5 lb Sulfur CoalPost CCM test w/ 2.5 lb Sulfur Coal &
optimized O2 Curve
Comments
Original predicted performance assumes 0.013 lbs moisture / lb of air (80˚F & 60% Humidity).
This test was run @ full load on 5/30/10 prior to placing the CCM project in service.
This test was run @ full load on 6/24/10 after initial balancing of the coal burner lines and placing the secondary air registers in automatic.
This test was run @ full load on 8/16/10 w/ stable O2 & CO parameters. The O2 curve had been adjusted down to optimize overall boiler efficiency.
Adjustments / VariablesExcess Air 20.0 16.0 15.0 11.0
Humidity 60% 80% 80% 80%Average Air Heater Exit Gas Temperature ˚F 262 317 319 315
Annual Capacity Factor 85% 71% 71% 71%% Dry Carbon in Refuse --- 4.00 2.70 3.20
Boiler Efficiency ParameterDry Gas Loss % 4.43 5.36 5.28 4.99
Water from Fuel Loss % 5.91 5.15 5.13 5.12Moisture in Air Loss % 0.11 0.21 0.20 0.19
Unburned Combustible Loss % 0.30 0.51 0.34 0.41Radiation Loss % 0.15 0.15 0.15 0.15
Unaccounted for Manuf Margin % 1.50 1.50 1.50 1.50
Total Losses % 12.40 12.88 12.61 12.36
Overall Boiler Efficiency % 87.60 87.12 87.39 87.64Input in Fuel (MKB/HR) 6581.00 6717.48 6690.00 6662.11Input in Fuel (MLB/HR) 639.80 584.13 581.74 579.31Wet Gas Wt (MLB/HR) 6579.00 6892.86 6821.53 6570.70Tot air to Burn Equip (MLB/HR) 5891.00 6324.39 6254.89 6008.25
Additional “Soft” Benefits1. Reduced emissions 2. Reduced pulverizer wear 3. Reduced wear on Coal Yard equipment. 4. Reduced boiler tube & non-pressure part erosion due
to lower flue gas velocities. 5. Improved ESP performance due to lower flue gas
velocities. 6. Reduced potential for slagging and fouling events7. Improved Pressure part life due to improved
temperature profile8. Reduced ash disposal costs9. Reduced boiler tube failures due to reducing
atmospheres
ContactJoe Estrada – [email protected]
David Earley – [email protected]
Bill Kirkenir – [email protected]
