CFB_Presentation for CFB Boiler for low capacity

CFB Presentation

1. CFBC
Circulating Fluidized Bed
Combustion

2. 001 656p
Future utilization of oil and coal in utility and industrial
power stations depend on combustion systems which
meet the requirement of an extensive reduction of
emission
One solution with economical benefits is:
CCirculating FFluidized BBed
CCombustion

3. History
141 267p
Two CFB technologies have been developed
•One origin was a bubbling bed burning low grade fuels
•The other origin were gas/solid reactors for process technology
applications
End of 70ies first applications in coal combustion
Break through
•in the 80ies due to environmental legislation
Typically 200 mg/m³ NO
X and 200 - 1,000 mg/m³ SO
2 became
mandatory
•later due to utilisation of opportunity fuels

4. between Fixed Grate, Fluidized
Bed, and Pulverized Firing
Relationships
056 338p
Stoker Firing
(Fixed Bed)
Fluidized Bed Firing
BFB C FB
G as
Fuel
A irA sh
Velocity 8 - 10 ft/ sec
(2.3 - 3.0 m/ s)
4 - 10 ft/ sec
(1.2 - 3.0 m/ s)
Average Bed
Particle Size
6,00 0 m
Pulverized Firing
(Entrained Bed)
G as
Fuel
A ir
A sh
15 - 3 3 ft/ sec
(4.6 - 10.0 m/s)
50 m
G as
Fuel &
Sorbent
A irA sh
1,00 0 m 10 0 - 300 m
G as
Fuel &
Sorbent
A irA sh
15 - 2 3 ft/ sec
(4.6 - 7.0 m/ s)
A ir

5. Environmentally friendly
CFB technology generates power :
 High SO
2 capture
 Firing a wide variety of different fuels
 Low NOx emissions

6. SO
2 Capture
CaCO
3
--> CaO + CO
2

CaO + SO
2
+ ½ O
2
--> Ca SO
4


Furnace temperature control
is very critical
Limestone consumption varies
enormously with furnace
temperature

Optimum temperature :
850 °C
850800 900
SO
2
Capture efficiency
T (°C)
 SO
2 Capture achieved by
limestone injection

7. NOx Emissions
- Combustion temperature
- N
2 in fuel
- Excess air and staggering
1 000800 1 200
NOx
T (°C)
 NOx Emissions influenced by
3 main parameters :

8. General Process

Bed temperature
Air
Air
Air
Ash
Coal
Flue gas

Optimum
temperature :
850 °C
Temperature maintained by heat
pick up in exchange surfaces
Either in furnace
Or in FBHE

9. CFB Boilers

1
3
2
7
4
5
6
8
9

10. Main Design Criteria
High bed inventory of fine particles
High recirculation rate
Highly efficient cyclones
External and/or Internal heat exchangers for
temperature control depending upon the application
Concept

11. External Heat Exchangers
A very fine tuning of the bed temperature is
necessary
Fuel Analysis leads a small furnace
( Petroleum coke , Anthracites )
Very large electrical capacity CFB
Highly abrasive fuels
Concept
Advisable when :

12. Furnace
F B H E
Cyclone
FBHE Design

13. FBHE Design
Fluidisation
air
Ashes from
cyclones
Ashes to
furnace

14. Wing Walls
Could be used as
••Evaporator
••HP superheater
••Final reheater
Furnace
Erosion protection
(refratory)
Tube-fin-tube
design
to cyclone

15. Omega Panels
View from top
Double Super
Omega Design
Welded Design
Platen heaters within the furnace are a powerful
feature:
•To extract heat for superheating from the
furnace
•To have a self controlling system for furnace
heat extraction (no mechanical control means
needed)
•To avoid erosion of heating surfaces by
installation in the vertical flow area of the
furnace and smooth surface design
First unit has now gathered more than 100 000 h
operation with first platen heater equipment.

16. CFD Analysis
of Cyclone Performance
006 056px

17. (Results from Simulation)
Fractional Collection Efficiency
of Collection Systems
056 287p
0%
20%
40%
60%
80%
100%
120%
0 50 100 150 200 250
d [µm]
C
o
l
l
e
c
t
i
o
n

e
ffi
c
i
e
n
c
y
Cyclone
alternative collection system

18. Cyclone Improvement
Measures
056 329p
Downward
Inclined
Inlet Duct
High Performance
Refractory for Inlet Area
Eccentric Vortex
Finder Arrangement
Advanced Vortex
Finder Shape
Second Pass

19. (Old and New Cyclone Design)
Particle Size Distribution
of Solid Inventory
056 330p
10 µm100 1000
Grain size d
0.1
1.0
(%)
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
99.0
99.9
R
e
s
i
d
u
e

R
old cyclone designnew cyclone design

20. ••Maximize fine solid recirculation
••Increase carbon burnout as well as limestone utilization
••Increasing solid concentration in the upper furnace leads
to
•• enhanced heat transfer
•• perfect temperature homogenity
•• Fine PSD of inventory and thus less erosions
•• Minimize solids entrained to the backpass and thus
•• less backpass erosion
•• less backpass fouling
•• lower CO generated in the backpass
High Efficient Cyclone Benefits
056 343p

21. Cyclone Arrangements
056 352p
< 100 MW
el
200 - 300 MW
el 300 MW - 400 MW
el
100 - 200 MW
el
600 MW
el

22. 125 MWe, 250 MWe and
Beyond
Class 150 MW
+ +
+ +
++
+ + +
+ + +
Class 350 MW Class 600 MW

23. Performance of CFB boilers
EMILE
HUCHET
PROVENCE RED HILLS GOLDENBERG TAMUIN
OUTPUT
MWe
FUEL
THERMAL
EFF.
DeSOx
NOx
mg/Nm3
125 250 250 115 130
Coal
Coal slurry
Coal ( 4%S )
Pitch
Lignite Brown coal Petcoke
> 89 % > 94 % > 93 % > 89 % > 92 %
> 90 % > 97 % > 95 % > 95 % > 90 %
< 200 < 250 < 250 <200 <200
1991 1996 2001 1992 2002
CAN
160
Lignite Lignite
AKRIMOTA
125
> 92 % > 83 % (*)
> 95 % > 95 %
250 215
2002 2003
(*) HHV basis

24. Emissions achieved CFBs
in Relation to the Fuel Type
058 180p
Fuel Type NOX
mg/m³stp, 6 % O2
SO2
mg/m³stp, 6 % O2
Desulphurization
Efficiency
%
Anthracite & Anthracite tailings 70 220 80
Petcoke 100 200 97
Slurry 110 140 95
Bituminous Coal 80 200 95
Eastern US Bituminous Coal 60 100 97
High Moisture Lignite 140 200 90
High Sulphur Lignite 160 200 97
Biomass 100 - -

25. Ash Screw Cooler
056 340p
Ash from Furnace
1560 - 1650 °F
850 - 900 °C
Ash to Bottom Ash
Handling System
400 °F / 200 °C
(Typical)

26. Details
Ash Screw Cooler
056 341p
Holo-Flite Screw
Trough Jacket
Heat Exchanger

27. Water Cooled Ash Cooler
056 323p
Return to furnace
Ash inlet duct from
furnace bottom
Conveyor ash
to ash silo
Fluidizing air

28. Split Loop Seal
056 232px
Coal
from Cyclone
to Furnace

29. Major Recent References:
Utility Boiler
012 188p
Power Station Mladá Boleslav
2 x 50 MW
Energy Supply for VW-Skoda Factory
•Technology -CFB
•Fuel -Bituminous
Coal
•Capacity t/h2 x 140
•Design Pressure bar145
•Temperature °C535
•Commissioning -1998
•Country -Czech
Republic
•Customer -SKO Energo

30. + 53.0 m
± 0.0 m
Power Station Cao Ngan,
2 x 50 MW
Longitudinal Section
012 223p
Live Steam
115bar (design pressure)
538°C
66kg/s (237.6 t/h)
Feedwater
223°C
Fuel
Vietnamese Lean Coal
Customer
VINACOAL, Vietnam

31. Utility Boiler
012 183p
Major References:
Power Station Ledvice
110 MW
CFB Fired Boiler in Czech Republic
•Technology -CFB
•Fuel -Brown Coal
•Capacity t/h350
•Design Pressure bar135
•Temperature °C545
•Commissioning -2001
•Country -Czech
Republic
•Customer -CEZ a.s.

32. Major References:
Utility Boiler
012 185p
Power Station Emile Huchet
125 MW
CFB Fired Boiler in France
•Technology -CFB
•Fuel -Bituminous
Coal
•Capacity t/h367
•Design Pressure bar155
•Temperature °C545/540
•Commissioning -1990
•Country -France
•Customer -SODELIF

33. Major References:
Utility Boiler
012 187p
Power Station Goldenberg
125 MW
Extra large Furnace due to wet
(up to 60 % water) Brown Coal
•Technology -CFB
•Fuel -Lignite
•Capacity t/h400
•Design Pressure bar135
•Temperature °C505
•Commissioning -1992
•Country -Germany
•Customer -RWE

34. Akrimota, 2 x 125 MW
Boiler with CFB
012 217pÄ
Live Steam
138bar
538°C
405t/h
Reheater Steam
36bar
537°C
375t/h
Feedwater
247°C
Fuel
High Sulphur
Lignite
± 0.0 m
+ 50.0 m

35. Major References:
Utility Boiler
012 184p
Power Station Tamuin
2 x 130 MW
CFB Fired Boilers in Mexico
•Technology -CFB
•Fuel -Petroleum
Coke
•Capacity t/h2 x 395
•Design Pressure bar154
•Temperature °C540/540
•Commissioning -2002
•Country -Mexico
•Customer -SITHE-IPG

36. Major References:
Utility Boiler
012 198p
RF#1&#2
2 x 150 MW
CFB Fired Boilers in Taiwan
•Technology -CFB
•Fuel -Petroleum
Coke
•Capacity t/h2 x 500
•Design Pressure bar149
•Temperature °C541
•Commissioning -2002
•Country -Taiwan
•Customer -FHI

37. Major Recent References:
Utility Boiler
012 154p
Power Station Çan
2 x 160 MW
First CFB Fired Boilers in Turkey
•Technology -CFB
•Fuel -Lignite
•Capacity t/h2 x 462
•Design Pressure bar199
•Temperature °C543/542
•Commissioning -2002
•Country -Turkey
•Customer -TEAS
+ 5 6 .7 m

38. Major References:
Utility Boiler
011 422p
Tonghae Thermal Power Plant
2 x 220 MW
Reheat CFB Boilers in
Republic of Korea
•Technology -CFB
•Fuel -Anthracite
•Capacity t/h2 x 693
•Design Pressure bar172
•Temperature °C541/541
•Commissioning -1998 and 1999
•Country -Republic of Korea
•Customer -Tonghae

39. Major References:
Utility Boiler
011 424p
Power Station Provence
250 MW
First 250 MW CFB Boilers in the world
•Technology -CFB
•Fuel -Bituminous
Coal
•Capacity t/h700
•Design Pressure bar193
•Temperature °C565/565
•Commissioning -1995
•Country -France
•Customer -SOPROLIF

40. Major References:
Utility Boiler
011 459p
Power Station Red Hills
2 x 250 MW
•Technology -CFB
•Fuel -Lignite
•Capacity t/h2 x 753
•Design Pressurebar203
•Temperature °C540/568
•Commissioning -2001
•Country -USA
•Customer -Choctaw
Generation

41. Major References:
Utility Boiler
011 423p
Power Station Guayama
2 x 250 MW
Reheat CFB Boilers in Puerto Rico
•Technology -CFB
•Fuel -Bituminous
Coal
•Capacity t/h2 x 819
•Design Pressure bar207
•Temperature °C540/540
•Commissioning -2003
•Country -Puerto Rico
•Customer -AES

42. 3 D Model
250 MW CFB for Indian Lignite
011 475p

43. NCV
MJ/kg
Water content
Weight % a.r.
Ash content
Weight % a.r.
Sulphur
% maf
Anthracite 16 8 37
Bituminous coal 19 - 29 7 - 24 3 - 25
Lignite 12 - 18 12 - 42 12 - 26 5.5 - 12
Brown coal 8 - 12 35 - 58 1 - 40 1 - 13
Special fuels:
Petcoke < 31.0 < 5 < 1 < 7
Wood chips 12 36 2
Coal slurry 10.5 33 30
Paper sludge 2.4 62 15
Sewage sludge 0.6 73 15
Bark 9 - 16 15 - 50 1 - 3 (20)
Fuels for
Circulating Fluidized Beds
056 295p

44. Reference Summary
141 269p
•• FuelsFuels
Coal and lignite
Water content up to 60 %
Ash content up to 40 %
Sulphur content up to 13 % maf
various opportunity fuels
(coal, slurry, sewage sludge, petcoke, bark, ...)
•• Water/Steam sideWater/Steam side
Natural circulation
Assisted circulation
Once-through (engineering study)
With/without reheat up to 560 °C
••CapacityCapacity
From 70 MW
th
up to 250 MW
el
600 MW
el
under investigation

45. Advantages of CFB
for High Sulphur Lignite
Desulphurization of > 97 % achievable
Reduced slagging tendency in the furnace
–No slagging due to pyrite of other sulphur components
–Reduced fouling in the backpass due to low
temperature
and even temperature profile
Higher boiler efficiency
–Marginal SO
3 in flue gas due to SO
3 capture by
limestone
–Therefore, flue gas exit temperature of 140 °C or less
056 374p

46. Lignite Fired CFB Plants
Sulphur content of 14 % (daf) commercially utilized in
CFB
Desulphurization of > 97 % achievable
Special attention must be given to cyclone
performance
Equal fuel / air / limestone feeding into the furnace
must be
ensured under all operating conditions
Intensive testing is highly recommended:
–mine operation
–coal analysis with emphasis on type of sulphur
–available limestone sources and limestone reactivity
–combustion tests give valuable results
Conclusion
056 377p

47. Summary
001 673p
••CFB technology is well developed today
More than 300 CFB plants are operating or are under
construction
Plants with 250 MW capacity are running since 1995
••CFB technology meets environmental requirements
NO
X
values less than 200 mg/m
3
s.t.p. and desulphurization
efficiencies higher than 97 % could be achieved
••CFB techhnology is able to burn a wide range of fuels
Especially high sulphur and/or high ash or high water coals
could be utilized