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CIUDENPonferrada, 9th – 13th September 2013
FundaciónCiudadde laEnergíaCIUDEN
Ponferrada 9th to 13th September 2013
Organised by: Hosted by:
CIUDENPonferrada, 9th – 13th September 2013
NOx emissions experiences in a 30 MWth Circulating Fluidized Bed
boiler under oxy combustion conditions
Manuel Gómeza, Jesús Ramosa, Benito Navarretea, Francisco Muñoza, Beatriz Gila, Pedro Oteroa, Reijo Kuivalainenb, Teri Hiltunenb
a Fundación Ciudad de la Energía, II Avenida de Compostilla, nº 2, Ponferrada (León), 24404, Spain
b Foster Wheeler Energia Oy, Relanderinkatu 2, FI-78201 Varkaus, Finland
CIUDENPonferrada, 9th – 13th September 2013
NOx
• Types
• Thermal• Fuel• Prompt
• NOx = NO + NO2
• N2O as separate component
CIUDENPonferrada, 9th – 13th September 2013
Study of NO and N2O emissions at CIUDEN´s 30 MWth CFB installation
working under both air and oxy-combustion conditions
Objective
CIUDENPonferrada, 9th – 13th September 2013
FLY ASHSILO
FLY ASHFEEDING SYSTEM
LIMESTONE SILO
LIMESTONEFEEDING SYSTEM
SAND SILO
SAND FEEDINGSYSTEM
FUELSILO FUEL
FEEDING SYSTEM
NATURALGAS
START-UP BURNER
SKID
BOILER FEED WATER
FUE GAS
BOTTOM ASH
FLY ASHSYSTEM
PRIMARY OXIDANT
PRIMARYOXIDANT FAN
OXYGEN
SECUNDARY OXIDANT
SECUNDARYOXIDANT FAN
MIXER
FLY
ASH
R
ECIR
CU
LATI
ON
LIM
ESTO
NE
SAN
DFU
EL F
EED
AMMONIATANK
MIXER
MIXER
Experimental Installation
CIUDENPonferrada, 9th – 13th September 2013
Cyclon+Bag Filter
FLUE GAS RECIRCULATION
O2
NO/N2O measurement
Instrumentation
AIR
CIUDENPonferrada, 9th – 13th September 2013
Stability Period
bed temperature (ºC)
O2 excess (vol.% wet basis)
Steam flow (kg/h)
flue gas flow (kg/h)
SO2(ppmV)
coal flow (t/h)
STABLE PERIOD
CIUDENPonferrada, 9th – 13th September 2013
NO
N2O
Bed Temperature
NO/N2O determination
CIUDENPonferrada, 9th – 13th September 2013
Operating variables influencing NOand N2O emission
• Temperature
• Limestone addition
• Load
• Oxygen content in the oxidant (FGR ratio)
• Primary/secondary oxidant distribution
CIUDENPonferrada, 9th – 13th September 2013
Fuel 1- AnthraciteProximate analysis (wt. %)
Moisture content (as received)
4.95
Ash (dry basis) 34.14Volatiles (dry basis) 7.57
Fix carbon (dry basis) 58.28Ultimate analysis (wt. % dry basis)
C 58.27H 1.95N 0.79S 0.98
HHV (Kcal/kg, wet basis) 5040
CIUDENPonferrada, 9th – 13th September 2013
• Air/oxy modes• Different bed temperatures• Different limestone injection rates• High load operation• 3-5 excess oxygen (vol. % db)• Primary/secondary oxidant ratio = 0.8 - 0.9 (exceptionally 0.6 - 0.7)
Testing conditions
CIUDENPonferrada, 9th – 13th September 2013
0
50
100
150
200
250
300
840 860 880 900 920 940
NO
ppm
vw
et
Temperature (°C)
0
50
100
150
200
250
300
1 2 3 4
Ca/S molar ratio
AIR OXY
CIUDENPonferrada, 9th – 13th September 2013
0
50
100
150
200
250
300
840 860 880 900 920 940
N2O
ppm
vw
et
Temperature (°C)
0
50
100
150
200
250
300
1 2 3 4Ca/S molar ratio
AIR OXY
CIUDENPonferrada, 9th – 13th September 2013
Fuel 2- Blend: Anthracite/Petcoke(70/30 % weight)
Proximate analysis (wt. %)Moisture content (as
received) 4.83
Ash (dry basis) 24.65Volatiles (dry basis) 8.05
Fix carbon (dry basis) 67.30Ultimate analysis (wt. % dry basis)
C 66.29H 2.42N 1.06S 2.24
HHV (Kcal/kg, wet basis) 8381
CIUDENPonferrada, 9th – 13th September 2013
• Air/oxy modes• Different bed temperatures• Different limestone injection rates• High load operation• 3-5 excess oxygen (vol. % db)• Primary/secondary oxidant ratio = 0.80 - 0.90 (exceptionally 0.6 - 0.70)
Testing conditions
CIUDENPonferrada, 9th – 13th September 2013
0
50
100
150
200
250
300
840 860 880 900 920 940
NO
ppm
vw
et
Temperature (°C)
0
50
100
150
200
250
300
1 2 3 4Ca/S molar ratio
AIR OXY
CIUDENPonferrada, 9th – 13th September 2013
0
50
100
150
200
250
300
840 860 880 900 920 940
N2O
ppm
vw
et
Temperature (°C)
0
50
100
150
200
250
300
1 2 3 4
Ca/S molar ratio
AIR OXY
CIUDENPonferrada, 9th – 13th September 2013
NH3 injection
• 25 % weight water solution• Oxy-combustion conditions• Limestone injection• 3-5 % excess oxygen (vol. % db)• Different bed temperatures•Primary/secondary oxidant ratio = 0.8 - 0.9 (exceptionally 0.6 – 0.7)
CIUDENPonferrada, 9th – 13th September 2013
NH3 injection
Selected point
CIUDENPonferrada, 9th – 13th September 2013
0
50
100
150
200
250
300
0 2.3 3.4 4.6
NO
ppm
vw
et
Kg NH3/h
T = 920
T = 904
T = 892
T = 890
T = 888
T = 865
T = 855
CIUDENPonferrada, 9th – 13th September 2013
0
50
100
150
200
250
300
0 2.3 3.4 4.6
N2O
ppm
vw
et
Kg NH3/h
T = 920
T = 904
T = 892
T = 890
T = 888
T = 865
T = 855
CIUDENPonferrada, 9th – 13th September 2013
Preliminary Conclusions• NO dominates NOx emission
• NO emission increases with temperature increase• N2O emission decreases with temperature increase
• NO emission increases with limestone addition increase• High limestone addition rates do not affect N2O emission
• NH3 injection decreases NO emission• NH3 injection does not affect N2O emission
CIUDENPonferrada, 9th – 13th September 2013
Future research work
• Validation of these preliminary results
• Influence of operating conditions
• Heterogeneous reactions (solid-gas phases)
• Other fuels. Same behaviour?
CIUDENPonferrada, 9th – 13th September 2013CIUDENPonferrada, 9th – 13th September 2013
Acknowledgement
The work presented is co-financed under the “FP7 FLEXIBURNCFB” and
the “EEPR09-CCS- COMPOSTILLA” projects.
The European Union is not responsible for any use that may be made of the information contained therein.
CIUDENPonferrada, 9th – 13th September 2013CIUDENPonferrada, 9th – 13th September 2013
THANK YOU VERY MUCH FOR YOUR ATTENTION
For further information, please contactManuel Gómez, [email protected]
