Supercritical CFB Boiler
Designed for Low Grade
South African Coals.
Damian Goral
CFB Product Director, Doosan Lentjes, Germany
The range of heating value, ash, volatiles, sulphur
and moisture content
Performance and cost
The environmental requirements
CFB BOILER PRINCIPLE
Relatively low combustion temperature
typically < 900°C
Uniform temperature distribution
Limited formation of thermal NOx
In-situ SOx capture by addition of
limestone to combustion chamber (no
need for external FGD)
Very good fuel –air mixing conditions
Thermal inertia on circulating bed is not
sensitive for fuel quality change
KEY FEATURES
IN-BUILT FUEL FLEXIBILITY
FLOW DIAGRAM
PLANT EFFICIENCY / CO2 RATE
Applicability range for SC and USC CFB boilers
CFBB APPLICATION RANGE
BERLIN ONCE-THROUGH CFB
DESIGN DATA
Electrical Output
Steam PressureSteam Temperature
MWe
bar (sh/rh)°C (sh/rh)
1 x 100
196/43540/540
FUELSSulphur
Ash
MoistureHHV
% wt
MJl/kg
1.1
6.7
7.230
% wt
% wt
Hard Coal,Biomass
EMISSIONSSOx
NOx
mg/nm3 200
200% wt
Dust % wt 20
BERLIN CFB FUEL FLEXIBILITY
STAROBESHEVO 210 MWE CFB
DESIGN DATAElectrical Output
Steam PressureSteam Temperature
MWth
bar (sh/rh)°C (sh/rh)
1 x 210MWe
134/25545/542
FUELS
Sulphur
Ash
MoistureLHV
% wt
MJl/kg
1-2.5
16-50
6-1012-25
% wt
% wt
Anthracie, Anth. Sludge
EMISSIONSSOx
NOxmg/nm3 200
200mg/Nm3
Dust mg/Nm3 30
STAROBESHEVO FUEL FLEXIBILITY
USC CFB FOR RSA COAL
DESIGN DATA
Thermal Output
Steam PressureSteam Temperature
MWe
bar (sh/rh)°C (sh/rh)
300-600
250-280 /54-58560-610/595-620
FUELS
Sulphur
Ash
MoistureHHV
% wt
MJl/kg
0,6-1,5
35-55
5 - 128-15
% wt
% wt
Hard Coal,Lignite
USC CFB FOR RSA COAL
USC 300MWe USC 600 MW
USC CFB FOR RSA COAL
Red Blue
USC 300 MWe USC 600 MW
L = 86,0m 104,3m
B = 62,0m 63,4m
H = 74,9m 75,7m
USC CFB FOR RSA COAL
ESIMATED CO2 REDUCTION FOR RSA COAL
Design CaseSubcritical
drum type
Supercritic
al Benson
Posiflow
Ultra
Super
Critical I
Benson
Posiflow*
SH steam ( bar ) 175 256 281
SH steam ( °C ) 565 570 610
HRH steam ( bar ) 38 54 58
HRH steam (°C ) 565 595 621
Plant net Efficiency (LHV) 39,6% 41,8% 42,4%
ESIMATED CO2 REDUCTION FOR RSA COAL
■ Higher Efficiency due to larger Boiler
and higher Steam Parameters (up to
USC)
■ Dilution of Biomass Alkaline Content
by Coal Ash, less Risk of Fouling
■ Sufficient Ash from Coal, no Sand
Addition required
■ S/Cl ratio >4, no Risk of Cl Corrosion
■ Reduced Ash Discharge
■ Less Limestone Consumption (Lower
Base SO2)
BIOMASS CO-FIRING
Polution typeTypically
Requested
Achievable
due to CFB
technology
without
external
systems
Low cost SNCR
in use
SO2 (6 % O2, dry) mg/Nm³ 500 150 - 300 -
NOx as NO2 (6 % O2,
dry)mg/Nm³ 510 250 - 350 150 - 200
Dust mg/Nm³ 50 10 - 30 -
EMISSION CONTOROL IN CFB
CFB BOILER AVAILABILITY
Reference Data 2 x 175 MWe Lignite fired CFB
The availability data includes scheduled & un-scheduled outages
Total availability average from 1992 – 2015 is 91,5 %
SUMMARY
Supercritical and Ultra Supercritical
CFB technology is proven and available.
Flexibility in fuel quality allows not only
use of low quality coals but also
addition of biomass
SC and USC steam parameters allow
to reduce CO2 footprint of the plant.
Inherently low NOx emission and
simple SO2 removal decrease
environmental pollution.
THANK YOU고마워
VERTICAL TUBE DESIGN
High water flow rates lead to high dynamic
losses
When extra heat is applied to a tube or group
of tubes, the overall pressure drop increases
significantly.
The flows in the affected tubes have to fall to
match the overall circuit pressure drop.
Circuits designed with low water flow rates are
dominated by static pressure drops
When extra heat is applied the static pressure
drop and overall pressure drop fall.
The flows in the affected tubes have to
increase to match the overall circuit pressure
drop. (= positive flow response)
High mass flow
Static pressure losses
Dynamic pressure
lossesLow mass
flow
1800 1800 1250 700 700 777
100 115 115 100 115 115
High water flow rates lead to high dynamic
losses
When extra heat is applied to a tube or group
of tubes, the overall pressure drop increases
significantly.
The flows in the affected tubes have to fall to
match the overall circuit pressure drop.
Circuits designed with low water flow rates are
dominated by static pressure drops
When extra heat is applied the static pressure
drop and overall pressure drop fall.
The flows in the affected tubes have to
increase to match the overall circuit pressure
drop. (= positive flow response)
High mass flow
Static pressure losses
Dynamic pressure
lossesLow mass
flow
1800 1800 1250 700 700 777
100 115 115 100 115 115
LOW MASS FLUX DESIGN
UNIFORM TEMPERATURE DISTRIBUTION