usc boiler

1BABCOCK-HITACHI K.K.

Ultra Super Critical Pressure Coal Fired Boiler - State of the Art Technology Applications -

Ultra Super Critical Pressure Coal Fired Boiler - State of the Art Technology Applications -

Yoshio ShimogoriYoshio Shimogori


1. Improvement of Steam Conditions

2. Improvement of Material and Manufacturing Technology

3. 1000MW Hitachi-Naka No.1

4. Next-Generation USC Boiler






* Thermodynamic quantity

Super Critical means no distinction between water and steam Super Critical means no distinction between water and steam

200

300

400

500

600

1,000

1,500

2,000

2,500

3,000

500

3,500

10 20 30100

Crit

ical

(22.

06M

Pa)

Super CriticalSub-Critical

Steam(Gas)

Mix. Of Steam & Water

Water

Saturated line

Pressure(MPa)

Tem

p.(o

C)

Enth

alpy

＊(k

J/kg

)

Fig.1 What is Super Critical


PurposePurpose High Plant EfficiencyHigh Efficiency Coal UtilizationLow Emission (CO2 etc.)

USC ConditionUSC Condition

USCUSCOver SC Condition

Example25.0MPa/600℃/600℃

Super CriticalSuper Critical

24.1MPa/538℃ or 566℃

Critical Point Critical Point of Waterof Water

22.06MPa/374℃

* Steam Condition shows Turbine inlet

Fig.2 Ultra Super Critical (USC) TechnologyFig.2 Ultra Super Critical (USC) Technology


Fig.3 Steam Conditions of Coal Fired Boiler Improvement by BHK

24.1MPa/538/566oC

24.1MPa/566/593oC

24.5MPa/600/600oC

24.1MPa/593/593oC

1990 20001995 2005

Year

1985 2010

Tachibanawan No.2 (1050MW)Haramachi No.2 (1000MW)

Matsuura No.2 (1000MW)Nanao-Ohta No.1 (500MW)

Shinchi No.1 (1000MW)Noshiro No.1 (600MW)

Hekinan No.2 (700MW)Matsuura No.1 (1000MW)

Takehara No.3 (700MW)

Hitachinaka No.1 (1000MW)

25.0MPa/600/610oC

Ultra Super Critical

Super Critical

Canada (495MW)USA (870MW)


40

41

42

43

44

16.6MPa 538/538OC

16.6MPa 538/566OC

24.1MPa 538/566OC

24.1MPa 566/566OC

24.1MPa 566/593OC

24.1MPa 593/593OC

24.5MPa 600/600OC

Gro

ss P

lant

effi

cien

cy (%

) HH

V ba

se

45

Fig.4 Improvement of Plant Efficiency

Sub critical Super critical USC


Notes NC:Natural Circulation OT:Once-Through Circ.:Circulation O/D:Outside Diameter

FurnaceConstruction

Operating Pressure Sub-Critical(Constant or Sliding)

Benson Boiler(Spiral Type)NC Boiler (Vertical Type)

Sub-Critical to Supercritical Region(Sliding Pressure)

Applicable Steam PressureThrough Furnace Enclosure TubesTemperature UniformityMass Flow RateSliding Pressure Operation ?

Max. Unit Capacity in Operation

Furnace Enclosure ConstructionTube O/D (mm)

Start-up Time (min.) (Hot start)

Allowable Min. Load (%)

Load Change Rate

Subcritical Supercritical & Subcritical

BetterApprox. 13%

YES

Much Better100%

YES (Wide Range)

15 25 - 35 (OT Mode)15 (Circ. Mode)

Base Higher120 – 150 with TB By-pass 120 – 150 with TB By-pass

57.0 - 63.5 31.8 - 38.1600 MW 1,050 MW

Vertical Spiral

Table 1 Boiler Type and Furnace Construction

Feed Water

Down

Com

er

DRUM

Steam FeedWater


Fig.5 Boiler Types Supplied by BHK Group

Capacity (MW)

Pressure

Steam temp. (oC)

Boiler type

Coal combustion method

Coal kind

50 ~ 600

Subcritical

Up to 571

PCF (Opposed)

Bituminous, Sub-bituminous

PCF (Opposed)

~ 930

Subcritical,Supercritical

Up to 580

PCF (Opposed, Tangential), Slag tap

Bituminous, Sub-bituminous, Lignite, Anthracite

NC UP BENSON(Tower Type)

BENSON(Two Pass Type)

350 ~ 1000

Up to 571

Subcritical, Supercritical

75 ~ 1050

Up to 613

Subcritical,Supercritical

Notes NC:Natural Circulation UP : Universal Pressure

Supplied by BBPS (Babcock Borsig Power Systems)


Fig.6 Wide Range of Coal Qualities Fired

0

10

20

30

40

50

60

70

80

0 10 20 30 40Net calorific value, MJ/kg

Vola

tile

Mat

ter (

dry

ash

free

), % Lignite

Anthracite

BItuminous

Sub Bituminous


2.25Cr1.6WVNbSA335P23(HCM2S)

2.25Cr1MoSA335P22

9Cr1MoSA335P9

12Cr1MoVX20CrMoV121

9Cr2MoJIS:STPA27(HCM9M)

9Cr1MoVNbSA335P91(Mod.9Cr1Mo)

12Cr1Mo1WVNbJIS:SUS410J2TP(HCM12)

11Cr0.4Mo2WCuVNbSA335P122(HCM12A)

9Cr0.5Mo1.8WVNbSA335P92(NF616)

Creep Rupture Strength (600oC/105h)

30 - 40MPa 60MPa 100MPa 140MPa

:Conventional

Fig.7 Development Progress of Ferritic CrMo Steel Pipes

:Advanced


0

Temperature (oC)

Allo

wab

le s

tres

s (M

Pa)

SA335P22(2.25%Cr)

SA335P91 (9%Cr)

SA335P92(9%Cr)

SA335P122(11%Cr)

SA335P23(2.25%Cr)

50

100

150

500 550 600 650 700

Fig.8 Allowable Stresses of Ferritic CrMo Steel Pipes


18Cr10NiTi18Cr8Ni

25Cr20Ni

18Cr10NiNb

25Cr20NiNbNSA213TP310HCbN(HR3C)

20Cr25Ni1.5MoNbTiJIS:SUS310J2TB(NF709)

Creep Rupture Strength (650oC/105h)

55 - 60MPa 90MPa 110 - 120MPa

18Cr10NiNbTiJIS:SUS321J1HTB(Tempaloy A-1)

18Cr9Ni3CuNbNSA213-UNS30432(SUPER304H)

: Conventional: Advanced

SA213TP304H SA213TP321H

SA213TP347H

JIS:SUS310TB

21Cr32NiTiAlAlloy800H

Fig.9 Development Progress of Austenitic Stainless Steel Tube


0

Temperature (oC)

Allo

wab

le s

tres

s (M

Pa)

SA213TP321H(18%Cr)

SA213UNS S304 32(18%Cr:Super 304H )

SA213TP310HCbN(25%Cr:HR3C)

JIS:SUS310J2TB(20%Cr:NF709)

JIS:SUS321J1TB(18%Cr:Tempaloy A1)

550 600 650 700 750

50

100

150

Fig.10 Allowable Stresses Advanced Stainless Steel TubesFig.10 Allowable Stresses Advanced Stainless Steel Tubes


SA213UNS30332

SUS310J2TB

SA213TP310HCbN

SA335P92 SA335P122

Fig.12 Macro Structures ofNarrow Gap TIG Weld

Fig.11 Macro Structures ofTIG Weld of Tube Materials


Temperature (oC)

Inne

r sca

le th

ickn

ess

(mic

ro m

)

0

Time:1,000h

SA213UNS S304 32(18%Cr:Super 304H)

A213TP310HCbN(25%Cr:HR3C)

JIS:SUS310J2TB(20%Cr:NF709)

ShotblastedA213UNS S304 32

(18%Cr:Super 304H)

550 600 650 700 750 800

20

30

40

50

10

SA213TP347HFG(18%Cr:Fine Grain)

Fig.13 Steam Oxide Scale of Stainless Steel Tubes


Fig.14 Improvement Trend of Hitachi NR Series Burners

NR2 BurnerDual Burner NR3 BurnerNR BurnerDelayed Combustion Rapid ignition(In Flame NOx Reduction)

Guide sleeveFlame StabilizingRing

Swirler

Space CreatorFlame StabilizingRing

P.C. Concentrator

Flame StabilizingRing＋Baffle Plate

Guide sleeve

Spin Vane

Air register

P.C. Concentrator

Coal propertyFuel Ratio：1.8Nitrogen:1.5%Two Stage Combustion

1980 1985 1990 1995 20000

100

200

300

400

NO

x (6

%O

2,pp

m)

300 ppm(100%)Coal propertyFuel Ratio : 2.2Nitrogen : 1.8%Two Stage Combustion

Dual Burner(Conventional)

NR2 BurnerNR Burner NR3 Burner

175 ppm(60%)150 ppm(50%) 125 ppm(40%)

（100 ppm(33%)）


Fig.15 Side View of Hitachi-Naka No.1 Boiler

NO Ports

Burners

Steam Separator

Secondary Superheater Tertiary Superheater

Reheater

Primary Superheater

Economizer

DeNOxSystem

Air Heaters

Mills

CoalBunker

Primary AirFans

Forced Draft Fans

Boiler CirculationPump

Coal Feeders


Table 2 Main Specification of Hitachi-Naka No.1

Generator Output 1000 MW

Boiler TypeBabcock Hitachi Supercritical Sliding Pressure Operation Benson Boiler

Steam Pressure Main 24.5 MPa(g)

Main 600 oC Steam Temperature Reheat 600 oC

MCR

Economiser Inlet Feedwater Temp. 286.9 oC

Combustion System Pulverised Coal Fired

Draught System Balanced Draught System

Main Water Fuel Ratio Control andStaged Spray Attemperation Steam Temperature

Control System Reheat Parallel Gas Dampering andSpray Attemperation


Fig.15’ Side View of Hitachi-Naka No.1 Boiler

Spiral wall with opposed firing

Optimized heating surface arrangement

High strength material SA335P122, SUPER304H

Parallel gas damper with adequate heating surface


200

250

300

350

400

450

500

550

600

650

0 1000 2000 3000

Main Steam Flow (t/h）

Stea

m a

nd W

ater

Tem

pera

ture

(oC

) Reheater Outlet

Economizer Inlet

Economizer Outlet

Reheater Inlet

Superheater Inlet

Superheater Outlet

30%ECR 50%ECR 75%ECR 100%ECR

Fig.16 Steam and Water Temperature


Hitachi-Naka No.1 without Gas Recirculation

Previous Design with Gas Recirculation

(oC)550

Load Demand

Reheater outlet steam temperature

50%

3%/min

100%

0 30min. 0 30min.

650Damper opening degree (Reheater side)

Fig.17 Reheater Outlet Steam Temperature during Load Change


B CoalAustralia

7.41.99

1.8

CoalCountry

Fuel Ratio (-)

N(dry%)

IndonesiaA Coal

1.009.31.3

Ash(dry%)

0

2

4

6

8

100 120 140 160 180 200Unb

urne

d C

arbo

n in

Ash

(%)

Target Point

100%ECR

A Coal

B Coal

NOx at Boiler Outlet (ppm 6%O2)

Fuel Ratio = Fixed Carbon

Volatile Matter

Fig.18 Combustion Test Results at 100% Load


Flame of Hitachi NR3 Burning B Coal at Minimum Load

Fig.19 Flame of Hitachi NR 3 Burner at Minimum Load


Main Steam Pressure (MPa)

750

700

650

600

550

15 20 25 30 35

Germany/MARCKO DE2’99-’03

USA/VISION21 EU/THERMIEAD700’98-’13

Sub-Critical Boiler

Target for next generation

USC BoilerExisting USC Boiler

Mai

n St

eam

Tem

pera

ture

(oC

)Fig.20 Target Steam Conditions of Next-Generation USC Developing Project


Fig.21 Creep Rupture Strength for Material of Next Generation USCFig.21 Creep Rupture Strength for Material of Next Generation USC

Cre

ep R

uptu

re S

tren

gth

(10

5 hr,N

/mm

2 )

0

50

100

150

200

0

50

100

150

200

600 650 700 750 800 850600 650 700 750 800 850

Temperature (oC)

Alloy617 (52Ni22Cr)HR6W (40Ni23Cr)NF709 (25Ni20Cr)SA335P122(11Cr2W0.4Mo)

PipePipe TubeTube


Coal fired USC technology is established up to 600oC class steam conditionImprovement of material and manufacturing technology for boiler tubes and pipes increases steam conditions600oC class USC Boiler , Hitachi-Naka unit No.1, starts commercial operation with advance technology such as low NOx, high combustion efficiency and steam temperature control.Investigation for next Generation USC 700oC class is started.

Coal fired USC technology is established up to 600oC class steam conditionImprovement of material and manufacturing technology for boiler tubes and pipes increases steam conditions600oC class USC Boiler , Hitachi-Naka unit No.1, starts commercial operation with advance technology such as low NOx, high combustion efficiency and steam temperature control.Investigation for next Generation USC 700oC class is started.

SummarySummarySummary


SLIDING PRESSURE OPERATION

Thermodynamic loss byfalling in pressure

51015202530

20 40 60 80 10000Turbine Load (%)

0 20 40 60 80 100Turbine Load (%)

Unit output control method by sliding pressure is as follows.By the sliding pressure in proportion to the generator output, steam quantity at turbine inlet can be changed at a constant volume flow while keeping governing valve open.

A smaller governing valve loss enables improvement of high pressure turbine internal efficiency : A

Decrease of feed water pump throughput : B

Boiler reheat steam temperature can be maintained at higher level because of higher temperature in high pressure turbine exhaust steam : C

Improvement of Turbine Heat Rate due to Sliding Pressure Operation

A

B

C321012345

degr

adat

ion

Rel

ativ

e co

mpa

rison

of

Hea

t Rat

e (%

)im

prov

emen

tM

ain

Stea

m P

ress

. (M

pa )

In comparison to constant pressure operations, a slidingtype enables much improvement in plant efficiencyunder partial load operations.

Feature of Supercritical Sliding Pressure Operation


Next Generation USC30MPa 700/700oC

High Efficiency Coal Utilizations

2010200019901980 20302020

40

45

50

55(HHV)

Net

Pla

nt E

ffici

ency

(%)

Pulverized CoalBed FluidizedCoal GasificationHyper Coal

Pulverized Coal

PFBC

IGCC/IFGC

Hyper Coal

24.1MPa538/538oC

USC24.5MPa

600/600oC

USC30.6MPa

630/630oC

PFBC : Pressurized Fluidized Bed CombustionIGFC : Integrated Coal Gasification Fuel Coal

Combined CycleIGCC : Integrated Coal Gasification Combined CycleUSC : Ultra Super Critical

From : NEDO FORUM 2002

usc boiler

Documents

sliding pressure

steam conditions

super 304h

manufacturing

gas recirculation

notes nc

15 side view

allowable