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CETC
A Dual Fluid Bed Pilot Plant for Fuel Conversionand Co-firing Research
Fernando PretoBiomass & Renewables Group Leader
Advanced Combustion TechnologiesCANMET Energy Technology Centre – Ottawa
Natural Resources Canada
45th IEA FBC Meeting 18.11.2002
CETC
Fluidized Bed Combustion Pilot Plant ResearchCANMET Energy Technology CentreNatural Resources Canada
1980s Mark II AFBC unit 40 cm x 40 cm
1990s CFBC unit 40 cm ID (coal)
1995-> BFB unit (1 m ID)B: Bubbling & Biomass
Beyond-> Need for research beyond combustion
CETC
♦ Circulating Fluidized Bed Unit:0.8 MW thermal capacityrefractory lined, 0.4 m ID ~ 7 m highoperating temperatures up to 1000 C fluid. velocity to 8 m/sAutomated NG burnerDesigned for coal:
5 cm feed screw
Original CETC – CFBC Pilot Plant
CETC
♦ 1 MW Bubbling Fluidized Bed Unit:refractory lined,1 m ID - 6 m highoperating temperatures up to 1000 C fluidization velocity 1 – 3 m/sNG warm-up burner
Designed for biomass:25 cm overbed feed port15 cm underbed feed port
New BFB Pilot Plant
CETC Biomass Gasification Concept:- Wood Chips- Black Liquor
CETC
BFB
CFB
CFBCYCLONE
Riser 1
Riser 2
Star Valve
121 °CSaturated SteamFrom Main Boiler
Combustion Air
Cold Coke CycloneHot Coke Cyclone
12
14 16
08
24
2826
1004
18
2022
Pneumatic System
14 m high
CETC
Steam
“Cold” Circulation
Air“Hot” Circulation
A/burner
Baghouse
ID fanNCG
CETC-O Dual Fluid Bed Pilot Plant
Star Feeder
Stack
HXHX
Boiler
SH
LFF
L
Compressor
Compressor
Liq.
Solids Circulation: up to 6000 kg/h
CETC Dual Fluid Bed Pilot PlantBFB Transport CFB
CETC
CETC
BFB
CFB
CFBCYCLONE
Riser 1
Riser 2
Star Valve
121 °CSaturated SteamFrom Main Boiler
Combustion Air
Cold Coke CycloneHot Coke Cyclone
12
14 16
08
24
2826
1004
18
2022
CETC
Temperature Changes for the Cold Coke Cyclone
-100
0
100
200
300
400
500
6:36:02 AM6:55:00 AM7:13:56 AM7:32:52 AM7:51:52 AM8:22:28 AM8:41:24 AM9:07:01 AM9:31:52 AM9:50:48 AM
10:09 :44 AM10:28 :40 AM10:47 :36 AM11:06 :32 AM11:25 :28 AM11:44 :24 AM12:03 :20 PM12:22 :16 PM12:41 :12 PM
1:00: 08 PM1:19: 04 PM1:38: 00 PM1:56: 56 PM2:15: 52 PM2:34: 48 PM2:53: 44 PM3:12: 40 PM3:31: 36 PM3:50: 32 PM4:09: 28 PM4:28: 24 PM4:47: 20 PM5:06: 16 PM5:25: 12 PM5:44: 08 PM6:03: 04 PM6:22: 00 PM6:40: 56 PM6:59: 52 PM7:18: 48 PM7:37: 44 PM7:56: 40 PM
Tim e
Tem
p (o
C) Inside
Outside
delta T
Transport – Monitor & Control Point
CETCDUAL FLUID BED HEAT BALANCE
Heat In = Heat Out + Heat Loss
Cp Heat Heat HeatkJ/kg/K kJ/kg kJ/Hour kW
HEAT SINKSMain Steam 75 500 526 2.166 56.3 4224 1.2
Atom Steam 6.7 350 526 2.166 381.2 2554 0.7 Heat RequiredPurge Steam 0 120 526 2.166 879.4 0 0.0N2 Purge 10 25 526 1.0416 521.8 5218 1.4Bitumen Feed 318 319.7 526 1.735 892.9 283946 78.9
Total Heat Req'd 2732 295943 82.2
HEAT SOURCE
Coke Circulation 5070.1 606 526 1.6 128 648973 180.3 Heat Input
Feed Rate (kg/min) 5.3Star Feeder (RPM) 14.64
Temp. In (oC)
Rate (kg/hour)
Temp. Out (oC)
CANMET 1M Reactor
HC Processing
Atom
Main
Purge N2
Hot Coke
Heat Loss
Cold Coke
Steam + N2
HC Feed
Product
CETCKey Temperatures
0
100
200
300
400
500
600
700
800
Time
Grn avg. temp. Red avg. temp. TPHRTI T 036
14:18>VTB feed
15:37> Tracer study
17:28> Iso 1
19:23>Iso 2
.
CETCReactor Bed Temperatures (Zoom)
470
490
510
530
550
570
590
14:0
0:12
14:1
1:40
14:2
3:08
14:3
4:36
14:4
6:04
14:5
7:32
15:0
9:00
15:2
0:28
15:3
1:56
15:4
3:24
15:5
4:52
16:0
6:20
16:1
7:48
16:2
9:16
16:4
0:44
16:5
2:12
17:0
3:40
17:1
5:08
17:2
6:36
17:3
8:04
17:4
9:32
18:0
1:00
Time
Tem
pera
ture
(Deg
. C)
TEW 220 TEW 222 TEW 224 TEW 225 T
14:18> VTB feed 15:37> Tracer StudyBed 6.5'-7'
17:28> Iso 1Bed ~7'
.
SS conditions:BFB temperature: ±±±± 2 °°°°CCirculation Rate: ±±±± 80 kg/hFluidization Steam: ±±±± 1 %Bed height: ±±±± 0.1 m
Dual Fluid Bed Operation
CETC
CETCCo-Firing Biomass & Fluid Coke
Preparing biomass for co-firing involves "tuning" the fuel mix and “verifying” boiler operation so that there is little or no loss in total efficiency. Since biomass in general has significantly less sulfur than coke, there is an SO2 benefit and there may also be NOx reduction, but this has to be evaluated.
Investment levels are very site specific and are affected by the available biomass, determining handling, size reduction and drying facilities, and the type of burner modifications.
CETC
Ash deposition and boiler tube corrosion can be an issue for some co-firing arrangements, depending on the biomass, ash chemistry, and operating conditions. Biomass can contain considerable alkali and alkaline-earth elements and chlorine, which, when mixed with other gas components derived from coke such as sulphur compounds, promotes a different array of vapour and fine particulate deposition.
CONCERN: CFBC combustion of fluid coke is typically above 900 C. This is a potential problem for biomass ash agglomeration
Ash Issues
CETC
CETC
CETC
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6Height, m
Tem
pera
ture
, C
CokeWoodCo-firing 50/50
CFBC – Temperature Profiles
CETC CFBC – Co-firing Flue Gas
Ash Analyses & further work continuing….
NA90NANOx
15028530SO2, ppm
380260150CO, ppm
4.35.64.6O2, %
5.24.05.4Vel. m/s
Mix:50/50CokeWood