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Advanced Supercritical Boiler Technologies

Official Opening of the OxyCoalTM Clean Combustion Test FacilityTechnical Seminar

Dr David SmithDate: 24 July 2009

Page 1

AGENDA

• Why Advanced Supercritical?

• Advanced Supercritical : State of the Art

• Next step: Ultra Supercritical

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Page 2

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

CO2Reduction

TRACK 1: Increased Efficiency

TRACK 2: Carbon Capture and Storage (CCS)

Time

Baseline

- 95%

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WHY ADVANCED SUPERCRITICAL?

• Efficiency of the Rankine Cycle increases with increasing Turbine inlet Temperature and Pressure

• Cycle efficiency of typical sub-critical plant is 38% whereas today’s supercritical technology increases this to around 45-47%

220.89 250 290

540 570 610

Main Steam Pressure (bar)

Main Steam Temperature (°C)

Sub-Critical Super-CriticalAdvanced

Super-CriticalUltra

Super-Critical• Supercritical means above the “critical”

point for water / steam (220.89 bar) after which there is no phase change between water and steam

• Other terms “Advanced Supercritical” and “Ultra Supercritical” are loose definitions to indicate steps in technology as opposed to any distinction in thermodynamic properties

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Plant efficiency

% NCV

Increasing Efficiency

Lower CO2

emissions

1960 1980 2000 2020

35

40

45

50

55

30

Supercritical Boilers

Sub Critical Boilers

Year

Target AD700

50 – 55%

Doosan BabcockASC

46%

Meri PoriHemweg

New Chinese Orders

42%

Chinese fleet 38%

OlderPlants

Best Available Advanced Supercritical Technology being offered now – egKingsnorth, 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

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STEAM CYCLE AND PLANT EFFICIENCY GAINS

30

35

40

45

50

55

1960 1970 1980 1990 2000 2010 2020

Year

Effic

ienc

y (%

NC

V)

Sub-CriticalSupercritical

TargetAD700

166-568/568

159-566/566

166-568/568

239-540/560260-540/560

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

• Why Advanced Supercritical?

• Advanced Supercritical : State of the Art

• Next step: Ultra Supercritical

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WANGQU, SHANXI PROVINCE, CHINA

HOPPER KNUCKLE

MAIN STEAMOUTLET REHEATER

OUTLET

W ATERIMPOUNDED

HOPPER

REHEATER

PRIMARYSUPERHEATER

ECONOMISER

ECONOMISER

SEPARATORVESSEL

FINALSUPERHEATER

REHEATER

PLATENSUPERHEATER

TO STORAGEVESSEL

FURNACE ACCESS DOOR

Prep ared by Te rry E van s, J anu ary 200 4 f or W ang qu

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 is zero

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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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DEVELOPMENTS IN SUPERCRITICAL BOILERS

• PosiflowTM Best Available Technology for Once-Through boiler furnace

• Lower pressure drop means lower feed-pump power and lower through-life energy consumption

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

• With a PosiflowTM furnace the supercritical down-shot boiler can be realised: combines the economic and environmental benefits of supercritical steam conditions with anthracite combustion for the first time

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

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DEVELOPMENTS IN SUPERCRITICAL BOILERS: PLANT UPGRADE

• Supercritical Retrofit - existing plant can be upgraded to supercritical steam conditions with lower capital cost and more rapid timescale than new plant

• New boiler within existing structure• POSIFLOWTM vertical tube low mass flux

furnace• Re-use of other equipment (eg fans,

airheaters, coal mills) • New HP and IP turbine

• Doosan Babcock Upgrade of Yaomeng Power Plant in China 2002

• Owner chose not to upgrade to supercritical steam conditions…..

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

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Page 12

AGENDA

• Why Advanced Supercritical?

• Advanced Supercritical : State of the Art

• Next step: Ultra Supercritical

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Boiler concept for > 700°C

Generation 550MW Overall cycle efficiency >50%

Main Steam Pressure 365 bar-a Main Steam Temperature 705°C Reheat 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 750Ave

rage

Str

ess

Rup

ture

(MPa

) (10

0000

Hou

rs)

Metal Temperature (°C)

Ferritic AlloysAll available now Austenitic Alloys

Super 304H, 347HFG available nowSanicro 25 available – not yet codified

Nickel AlloysValidation 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

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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:

HR3CAustenitic

Alloy 740Nickel Alloy

Alloy 617modNickel 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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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 750Ave

rage

Str

ess

Rup

ture

(MPa

) (10

0000

Hou

rs)

Metal Temperature (°C)

Ferritic AlloysAll available now

Nickel AlloysValidation 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

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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 turbine and better utilise the low grade heat in the flue gas leaving the boiler

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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 turbine inlet

• 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 to further 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 about 20% 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 with improved cycles this will achieve a plant efficiency over 50% and about a 30% reduction in CO2compared to existing sub-critical plant

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

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Commercial Contact Details

Steve WhyleyGlobal Sales Director

Doosan Babcock Energy11 The BoulevardCRAWLEYWest SussexRH10 1UX

T +44 (0) 1293 612888D +44 (0) 1293 584908E swhyley2@doosanbabcock.com

Doosan Babcock is committed to delivering unique and advanced supercritical boiler technologies.