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