Behavior of sulfur during circulatingfluidized bed oxyfuel combustion
Results from an ADECOS-CFB Programme
Faculty for Mechanical Engineering – Institute for Energy Engineering. – Chair for Combustion, Heat and Mass Transfer
Ponferrada, 10.09.2013
Ing. Miroslav ČechDr.-Ing Andreas HillerProf. Michael Beckmann
2
Project ADECOS CFB
Motivation
Fluidized Bed Test Rig
Results of own research
Economical aspects
Conclusion and Outlook
Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
3
Project ADECOS ZWSF
Motivation
Fluidized Bed Test Rig
Results of own research
Economical aspects
Conclusion and Outlook
Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Project ADECOS ZWSF
Further development and research of Oxyfuel-Prozesson CFB-Firing, aimed on technical and economical feasibility
Teilprojekt 2ZWSF-Dampferzeuger einschl.
Rauchgasweg und -reinigung
Teilprojekt 1Simulation und Optimierung
des Gesamtprozesses
Teilprojekt 3Verbrennungsuntersuchungen
mit Braunkohle
Teilprojekt 4Verbrennungsuntersuchungen
mit Steinkohle
Project part 2CFB-Boiler simulationwith flue gas cleaningand desulphurization
Project part 1Simulation and
optimalization ofwhole process
Project part 3Experimental part
using Lignite
Project part 4Experimental partbituminous coal
4Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Project ADECOS ZWSF
Motivation
Fluidized Bed Test Rig
Results of own research
Economical aspects
Conclusion and Outlook
Main Advantage of CFB :
-Easy desulphurisation in the combustion Chamber-Effective and cost reducing
…will be different under Oxyfuel conditions:
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
500 600 700 800 900 1000 1100
Part
ial p
ress
ure
CO2
[bar
]
Temperature [°C]
CO2-CaCO3 equilibrium curve, replotted from E.H. Baker, The Calcium Oxide Carbon Dioxide System in the Pressure range 1-300 atm, J.Chem. Soc. 87 (1962), P 464-470
Direct Sulfation:
Indirect Sulfation:
Oxyfuel ->
5Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Project ADECOS ZWSF
Motivation
Fluidized Bed Test Rig
Results of own research
Economical aspects
Conclusion and Outlook …will be removed under Oxyfuel-Modus:
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
500 600 700 800 900 1000 1100
Part
ial p
ress
ure
CO2
[bar
]
Temperature [°C]
CO2-CaCO3 balance curve, replotted from E.H. Baker, The Calcium Oxide Carbon Dioxide System in the Pressure range 1-300 atm, J.Chem. Soc. 87 (1962), P 464-470
Direct Sulfation:
Indirect Sulfation:
Oxyfuel ->
6
CFB Test Rig
• Power output: 300 kW
• Primary Air / Recirculated Flue gas / O2
• Secondary Air /Recirculated Flue Gas /O2
• Design fuel: Lignite„Lausitzer Trockenbraukohle“
Ash 5,3 %massWater 18,2 %massCarbon 51,6 %massHydrogen 3,8 %massNitrogen 0,51 %massSulphur SCOMBUSTIBLE 0,583 %massChlorine 0,036 %massLower Heating Value 19,1 MJ/kg
Ca in the ash 15,56 %mass
Project ADECOS ZWSF
Motivation
Fluidized Bed Test Rig
Results of own research
Economical aspects
Conclusion and Outlook
7
• Cooling via integrated fluid bed cooler
• Valve and bed cooler fluidized by air/CO2
• Combustion chamber Ø320mm
• Height 12 m
12 0
00
Project ADECOS ZWSF
Motivation
Fluidized Bed Test Rig
Results of own research
Economical aspects
Conclusion and Outlook
Folie 8
Gas Concentration Measurement
‘‘Cyclone 2‘‘ Sampling
‘‘Filter‘‘ Sampling
9
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Comparison of SO2 Emissions between Air and Oxy firing mode: Variation of air excess
Air Mode Oxy Mode
SO2
SO2Max
0
100
200
300
400
500
600
700
0 2 4 6 8 10
SO
2[m
g/M
J BS]
Rest O2,dry [%vol]
SO2
SO2Max
0
100
200
300
400
500
600
700
0 2 4 6 8 10
SO
2[m
g/M
J BS]
Rest O2,dry [%vol]
840-880°C, 230 kW, no sorbent,no air staging
820-900°C, 230 kW, no sorbent1,2-5% N2 in flue gas, RR=62,5%
10Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Comparison of SO2 Emissions between Air and Oxyfiring mode: Variation of air excess
Air Mode Oxy Mode
SO2
SO2Max
S Ash 5.2
5.4
5.6
5.8
6
6.2
0
100
200
300
400
500
600
700
0 2 4 6 8 10
S in
Ash
[%
MASS]
SO
2[m
g/M
J BS]
Rest O2,dry [%vol]
SO2
SO2Max
S Ash
5.2
5.4
5.6
5.8
6
6.2
0
100
200
300
400
500
600
700
0 5 10
S in
Ash
[%
MASS]
SO
2[m
g/M
J BS]
Rest O2,dry [%vol]
840-880°C, 230 kW, no sorbent,no air staging, XRF-;Method for S content in ash
820-900°C, 230 kW, no sorbent0-2% N2 in flue gas, Recycle Rate=62,5%
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
Ponferrada, 10.09.2013 Behavior of sulfur in CFB-Oxy Combustion 11
Comparison of SO2 Emissions between Air and Oxyfiring mode: Variation of temperature
0
50
100
150
200
250
300
350
400
450
500
650 700 750 800 850 900
SO
2[m
g/M
J BS]
Temperature[°C]
Oxy: Temperature vs. SO2
0
50
100
150
200
250
300
350
400
450
500
650 700 750 800 850 900
SO
2[m
g/M
J BS]
Temperature[°C]
Air: Temperature vs. SO2Air 2-3%O2
Air 3-4%O2Air 4-6%O2
4% O2 in fluegas,
230 kW, 62% Recycle
Rateno sorbent,
no O2 staging,
4% O2 in fluegas,
235 kW, no sorbent,
no air staging,
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
12Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Comparison of SO2 Emissions between Air and Oxyfiring mode: Variation of false air intake
863-895°C, 230 kW, no sorbentAir excess = 4% of O2 in dry flue gas, RR=62%
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
71737577798183858789919395
0
50
100
150
200
250
300
0 2 4 6 8 10 12 14 16 18 20 22 24
CO2, dry [%vol]
SO
2[m
g/M
J BS]
N2 dry [ %VOL]
Oxy: N2 vs. SO2
13Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Gas Analy
sis
S1
0
2
4
6
8
10
12
650 750 850 950
Hei
ght
[m]
Temperature[°C]
Temperature profile
PL=100%
PL=80% S2=20%
Pl=83% S2=17%
0
2
4
6
8
10
12
0.8 0.9 1 1.1 1.2
Hei
ght
[m]
λLOCAL[-]
Oxygen excess profile
PL 100%
PL 85% ; S2 15%
PL 83% , S1 17%
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
14Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
-20%
-32,1%
-42%
SO2 at Exit
+9,6%
+88,7%
+126%
0
50
100
150
200
250
300
350
400
0
2
4
6
8
10
12
14
16
18
0% 5% 10% 15%
SO
2[m
g/
MJ B
S]
NO
[m
g/
MJ B
S]
Ratio O2 S1 / Total O2
Oxy: Oxygen Staging (S1) vs. NO and SO2
Oxygen Staging
842-905°C, 248 kW, no sorbentOxygen excess = 4% of O2 in dry flue gas, RR=62%, 8%
of recirculated flue gas through secondary gas inlet
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
15Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Sorbents overview
SORTE Limestone Dolomite 460µm Dolomite 370µm Calciumhydroxide
Mean
particle size[mm] 0,7904 0,4678 0,3713 0,0677
Silicium [%MASS] 0,00210 1,0039 1,64300 0,00309
Aluminium [%MASS] 0,06608 0,2233 0,49730 0,09736
Iron [%MASS] 0,04540 0,4487 0,58010 0,06689
Calcium [%MASS] 35,99699 21,4750 22,35000 53,0407
Magnesium [%MASS] 0,05731 13,4650 13,57500 0,08444
Sulfur [%MASS] 0,00658 0,0002 0,01539 0,00969
Natrium [%MASS] 0,30561 0,1300 0,12000 0,45030
Kalium [%MASS] 0,00992 0,0571 0,30105 0,01465
Spurstoffe [%MASS] 0,22037 0,1591 0,46037 0,32471
*Rest [%MASS] 63,28962 63,0378 60,45779 45,99
Photo
Limestone
Ca(OH)2
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Pass
thro
ugh
[%m
ass]
Particle size [mm]
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
Economical aspects
Conclusion and Outlook
16Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Desulphurisation using limestone
855-870°C, 250 kW, Sorbent:LimestoneAir excess = 4% of O2 in dry flue gas, RR=62,5%,
No air or O2 staging
CO2=95%vol,dry
CO2=94,8%CO2=94,4%
CO2=86,8%
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 2 4 6 8
η DES
OX[
%]
Ca/S Ratio[molCa/molS]
Oxy Air
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
17Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Analysis of cyclone/filter ash during desulphurization
855-870°C, 250 kW, Sorbent:LimestoneAir excess = 4% of O2 in dry flue gas, RR=62,5%,
No air or O2 staging
Calcium
Calcium
Sulfur
Sulfur
0
5
10
15
20
25
30
0 1 2 3 4 5
[%M
ASS]
Ca/S ratio [molCa/molS]
Air/Oxy: Limestone (Cyclone 2)
Ca Luft
Ca Oxy
S Oxy
S Luft
Calcium
CalciumSulfur
Sulfur
0
5
10
15
20
25
30
0 1 2 3 4 5
[%m
ass]
Ca/S ratio [molCa/molS]
Air/Oxy: Limestone (Filter)
Ca LuftCa OxyS LuftS Oxy
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
18Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Desulphurization using Dolomite
855-870°C, 250 kW, Sorbent:LimestoneOxygen excess = 4% of O2 in dry flue gas, RR=62,5%,
No staging
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 0.5 1 1.5 2 2.5 3 3.5
η DES
OX [%
]
Ca/S Sorbent Ratio [molCa/molS]
Air Dolomite 460
Air Dolomite 460
Oxy Dolomite 460
Oxy Dolomite 460
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
19Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Desulphurization using Dolomite
855-870°C, 250 kW, Sorbent:LimestoneOxygen excess = 4% of O2 in dry flue gas, RR=62,5%,
No staging
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 0.5 1 1.5 2 2.5 3 3.5
ηD
ESO
X[%
]
Ca/S Sorbent Ratio [molCa/molS]
Air Dolomite 460Air Dolomite 460Air Dolomite 370Oxy Dolomite 460Oxy Dolomite 460Oxy Dolomite 370Oxy Dolomite 370
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
20Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Desulphurization using Dolomite
855-870°C, 250 kW, Sorbent:DolomiteOxygen excess = 4% of O2 in dry flue gas, RR=62,5%,
No air or O2 staging
Calcium
Sulphur
0
5
10
15
20
25
0 1 2 3 4
[%]
Ca/S Verhältniss [molCa/molS]
Air/Oxy: Dolomite 460µm
Luft Ca
Luft S
Oxy Ca
Oxy S
Sulphur
Calcium
Calcium
Sulphur
0
5
10
15
20
25
0 0.5 1 1.5 2 2.5
[%]
Ca/S Verhältniss [molCa/molS]
Air/Oxy: Dolomite 370µm
Luft Ca
Luft S
Oxy Ca
Oxy S
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
21Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Desulphurization using Calcium Hydroxide Ca(OH)2
860-880°C, 248 kW, Sorbent:Ca(OH)2Air excess = 4% of O2 in dry flue gas, RR=62,5%,
No air or O2 staging
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
Behavior of SO2 undernormal conditions
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overwiew
(Economical aspects)
Conclusion and Outlook
Oxy
Air
0.01
0.1
1
10
100
1000
400 500 600 700 800 900
Part
ial P
ress
ure
p H2O
[bar
]
Temperature [°C]
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
0 1 2 3
ηD
ESO
X [
%]
Ca/S Ratio [molCa/molS]
Oxy
Air
Replotted from: S.Lin, Y.Wang, Y.Suzuki: High Temperature CaO Hydration and
Ca(OH)2 Decomposition over a Multitude ofCycles, in Energy & Fuels 23,2009, Page
2856-2861
22Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Overview of sorbents
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 1 2 3 4
η DE
SOX[%
]
Ca/S [molCa/molS]
Air firing
Ca(OH)2Dolomite 460Dolomite 370Limestone
60%
65%
70%
75%
80%
85%
90%
95%
100%
0 2 4 6 8
ηD
ESO
X[%
]
Ca/S [molCa/molS]
Ca(OH)2Dolomite 460Dolomite 370Limestone
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
23Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Economy of Desulphurization
Sorbent €/t Airt/DayOxy
t/DayAir
€/DayOxy
€/DayCa(OH)2 80* 88 98 7.100 7.800
Limestone 20** 271 - 5.400 -
Dolomite 370µm
33*** 207 312 6.900 10.300
Dolomite 460µm
30** 235 413 7.100 12.400
Reference power Plant 460 MWeNet Plant Efficiency 43,3%Fuel used for experiments : 55,5 kg/s
Sources:* Walhalla Kalk GmbH
**sh Minerals AG***Ostrauer Kalkwerke GmbH
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
24Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Overview
Direct desulphurization in the combustion chamber forOxyfuel firing is still possible, but the efficiency is lower thanfor air firing
Effect of particle size distribution of sorbent is relatively high
Ca(OH)2 as an alternative sorbent probably too expensive
Air/O2 Staging is an disadvantage for sulfurisation reaction
Slight decrease of CO2 Concetration in Oxy-Modus boosts theeficiency of desulphurization
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook
25Behavior of sulfur in CFB-Oxy CombustionPonferrada, 10.09.2013
Acknowledgement
Thank to our project partners and sponsors:
German Federal Ministry of Economic (COORETEC Programme)
Vattenfall
E.ON Energie AG
RWE Power AG
Linde AG
…and thankYou forYour attention!
Motivation
Recent research on SO2-Emissions
Fluidized Bed Test Rig
Results of own research
SO2 without sorbent
Sorbent Limestone
Sorbent Dolomite
Sorbent Ca(OH)2
Overview
Economical aspects
Conclusion and Outlook