advanced supercritical boiler technology

7/30/2019 Advanced Supercritical Boiler Technology

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Advanced Supercritical Boiler Technologies

Official Opening of the OxyCoalTM Clean CombustionTest Facility

Technical Seminar

Dr David SmithDate: 24 July 2009

AGENDA

• Why Advanced Supercritical?

• Advanced Supercritical : State of the Art

• Next step: Ultra Supercritical



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WHY ADVANCED SUPERCRITICAL?

• Both tracks are required to mitigate CO2 emissions from coal fired generation

• Primary means to increase efficiency is to increase the steam conditions we use in our power plant cycle

CO2

Reduction

TRACK 1: Increased Efficiency

TRACK 2: Carbon Captureand Storage (CCS)

Time

Baseline

- 95%

Page 3

WHY ADVANCED SUPERCRITICAL?

• Efficiency of the Rankine Cycleincreases with increasing Turbine inletTemperature and Pressure

• Cycle efficiency of typical sub-criticalplant is 38% whereas today’ssupercritical technology increases thisto around 45-47%

220.89 250 290

540 570 610

Main Steam Pressure (bar)

Main Steam Temperature (°C)

Sub-Critical Super-Critical

Advanced

Super-CriticalUltra

Super-Critical• Supercritical means above the “critical”

point for water / steam (220.89 bar) afterwhich there is no phase change betweenwater and steam

• Other terms “Advanced Supercritical” and“Ultra Supercritical” are loose definitions toindicate steps in technology as opposed toany distinction in thermodynamicproperties



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Plant

efficiency

% NCV

Increasing

Efficiency

Lower CO 2

emissions

1960 1980 2000 2020

35

40

45

50

55

30

Supercritical Boilers

Sub Critical

Boilers

Year

TargetAD700

50 – 55%

Doosan Babcock

ASC

46%

Meri PoriHemweg

New ChineseOrders

42%

Chinese fleet 38%

OlderPlants

Best Available Advanced

Supercritical Technology

being offered now – eg

Kingsnorth, Greifswald

38%

32%

UK

fleet

(-23%)

(-29%)

Meaningful CO2 reductions can be achieved by replacing old units with modern advanced supercritical

plant

DEVELOPMENT IN THERMAL EFFICIENCY

Page 5

STEAM CYCLE AND PLANT EFFICIENCY GAINS

30

35

40

45

50

55

1960 1970 1980 1990 2000 2010 2020

Year

E f f i c i e n c y ( % N C V )

Sub-Critical

Supercritical

Target

AD700

166-568/568

159-566/566

166-568/568

239-540/560

260-540/560

274-580/600

275-585/602

285-580/580

305-585/602

375-700/700

169-541/539

Main Steam Pressure (barg) – Steam Temperature Main / Reheat (°C)

Efficiency gains have mostly been achieved by pushing the steam cycle, lower excess air and lower

gas exit temperature have also contributed



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Page 6

AGENDA




Page 7

WANGQU, SHANXI PROVINCE, CHINA

HOPPER KNUCKLE

MAIN STEAMOUTLET

REHEATEROUTLET

WATERIMPOUNDED

HOPPER

REHEATER

PRIMARYSUPERHEATER

ECONOMISER

ECONOMISER

SEPARATORVESSEL

FINALSUPERHEATER

REHEATER

PLATENSUPERHEATER

TO S TORA GE

VESSEL

FURNACE ACCESS DOOR

Pre p are d b y Te rry E v an s ,J a nu ary 2 0 0 4 for Wa ng q u

2 x 600MWe Units

Evaporation 540 kg/s

S/htr Outlet Press 248 bar

S/htr Outlet Temperature 571°C

R/htr Outlet Temperature 569°C

Contract Effective 09/03

Operational 36 months later



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DEPLOYMENT OF SUPERCRITICAL TECHNOLOGY

China’s deployment of supercritical technology far outstrips other countries and regions – UK deployment iszero

Page 9

GREIFSWALD, GERMANY

2 x 800MWe Units

Evaporation 588 kg/s

S/htr Outlet Press 277 bar

S/htr Outlet Temperature 600°C

R/htr Outlet Temperature 605°C

PosiflowTM vertical tube furnace



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Page 10

DEVELOPMENTS IN SUPERCRITICAL BOILERS

• PosiflowTM Best Available Technology forOnce-Through boiler furnace

• Lower pressure drop means lower feed-pumppower and lower through-life energyconsumption

• Other advantages include better turn-down,simpler construction and improved availability

• With a PosiflowTM furnace the supercritical

down-shot boiler can be realised: combines theeconomic and environmental benefits ofsupercritical steam conditions with anthracitecombustion for the first time

• Doosan Babcock 2 x 600MW supercriticaldown-shot units for Zhenxiong, YunnanProvince, China.

Page 11

DEVELOPMENTS IN SUPERCRITICAL BOILERS: PLANT UPGRADE

• Supercritical Retrofit - existing plant can beupgraded to supercritical steam conditions withlower capital cost and more rapid timescalethan new plant

• New boiler within existing structure

• POSIFLOWTM vertical tube low mass fluxfurnace

• Re-use of other equipment (eg fans,airheaters, coal mills)

• New HP and IP turbine

• Doosan Babcock Upgrade of Yaomeng PowerPlant in China 2002

• Owner chose not to upgrade to supercriticalsteam conditions…..

• However, application of PosiflowTM furnace andcombustion system modifications gave 10%lower coal consumption and availability of 96%



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Page 12

AGENDA




Page 13

Boiler concept for > 700°C

Generation 550MWOverall cycle efficiency >50%

Main Steam Pressure 365 bar-a

Main Steam Temperature 705°CReheat Steam Temperature 720°C

Reduction in CO2 emission relative to sub-critical ~30%

ULTRA SUPERCRITICAL



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MATERIALS FOR ADVANCED STEAM CYCLES - TUBING

Steam cycle based efficiency gains are constrained by the availability of suitable alloys

0

50

100

150

200

250

300

500 550 600 650 700 750 A v e r a g e S t r e s s R u p t u r e ( M P a ) ( 1 0 0 0 0 0 H o u r s )

Metal Temperature (°C)

Ferritic Alloys

All available now Austenitic Alloys

Super 304H, 347HFG available now

Sanicro 25 available – not yet codifiedNickel Alloys

Validation ongoing

~550°C ~650°C ~700°C~600°CSteam Temperature

Note – maximum allowable temperatures are also limited by steam-side oxidation

Alloy 263

Alloy 740

Alloy 617

Sanicro 25

Super 304H

347 HFG

P92

T24

T23

Page 15

MATERIALS FOR ADVANCED STEAM CYCLES - TUBING

To put that in context consider a 48mm tube operating at 700°C with a design pressure of 380 bar:

HR3C

Austenitic

Alloy 740

Nickel AlloyAlloy 617mod

Nickel Alloy

Allowable Stress @ 750°C

(MPa)44.5 56.0 96.0

Calculated thickness

t = P.D / 2.σ (mm)20.5 16.2

9.5



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Page 16

MATERIALS FOR ADVANCED STEAM CYCLES – HEADERS AND PIPEWORK

Note – maximum allowable temperatures are also limited by steam-side oxidation

0

50

100

150

200

250

300

500 550 600 650 700 750 A v e r a g e S t r e s s R u p t u r e ( M P a ) ( 1 0 0 0 0 0 H o u r s )

Metal Temperature (°C)

Ferritic Alloys

All available now

Nickel Alloys

Validation ongoing

~600°C ~700°C~650°CSteam Temperature

Alloy 263

Alloy 740

Alloy 617P92

T24

T23

Austenitic alloys suffer from thermal fatigue, making them less suitable for thicker wall section

components

Page 17

MATERIALS FOR ADVANCED STEAM CYCLES – MANUFACTURING

Manufacturing processes for components from new materials require extensive validation

Test bending furnace wall panels in T23 material

Bend tests in Sanicro 25

Alloy 263 pipe production Alloy 263 weld qualification



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ULTRA SUPERCRITICAL – CYCLE OPTIMISATION

• In addition to improvements in Rankine Cycle efficiency from increasing steam temperatures we can makebetter use of low grade heat in our power plant cycle

• Feedwater heating can be optimised to reduce the quantity of high grade bled steam taken from the turbineand better utilise the low grade heat in the flue gas leaving the boiler

Page 19

SUMMARY

• Increasing plant efficiency is fundamental to reducing all emissions including CO2

• Primary means to increase efficiency is to increase the steam pressure and temperature at the turbineinlet

• This means using steam at supercritical pressures – we use terms such as “Advanced Supercritical” and“Ultra Supercritical” to indicate higher ranges of temperatures and pressures

• We can make improvements to the basic once-through boiler concept like the PosiflowTM furnace tofurther increase efficiency and operating flexibility

• Supercritical technology can be readily retrofitted to life-expired existing plant

• Today’s Advanced Supercritical plant will achieve around 46-47% cycle efficiency (LHV basis) and about20% reduction in CO2 for the same MWe output as existing sub-critical plant

• Ultra Supercritical plant operating at steam temperatures above 700°C is the next step. Together withimproved cycles this will achieve a plant efficiency over 50% and about a 30% reduction in CO2

compared to existing sub-critical plant

• Attainment of 700°C is constrained by the availability of suitable materials for the highest temperaturecomponents and development programmes are underway



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Commercial Contact Details

Steve Whyley

Global Sales Director

Doosan Babcock Energy

11 The Boulevard

CRAWLEY

West Sussex

RH10 1UX

T +44 (0) 1293 612888

D +44 (0) 1293 584908

E [email protected]

Doosan Babcock is committed to delivering unique and advanced supercriticalboiler technologies.

advanced supercritical boiler technology

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