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Bharat Heavy Electricals Limited Tiruchirappalli

FBC & HRSG

Best Practices

Learning and application

In Engineering

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Product profile

Bubbling Fluidized bed combustion (BFBC) boilers

Circulating fluidized bed combustion (CFBC) boilers

Heat recovery Steam Generator (HRSG)

BFBCs for low grade coal as fuels

CFBCs from 75 MW to 250 MW

HRSGs for Frame 5 GT to Frame 9FA GT

Product turnover 5 fold increase to Rs 1000 Cr. in a

span of 4 years

Introduction

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Current practiceAnalysis for improvement for

Ease of manufacture

Comfort for erection

Better performance

Implementation phase (initial)

Continual improvement lead to

Established product with best practices

Approach towards improvement

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Collecting feed back from operational experience of units

Learnings from site action requests and information

obtained during the visit of engineering personnel

Discussion with manufacturing group for ease of

manufacturing and erection

Discussion with erection group before finalisation ofarrangement engineering

Methodology adopted towards improvement

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SH Flow t/h 165

SH Pressure kg/cm2 95

SH Temperature Deg C 540

77 Mw BFBC Power plant - Jindal

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50 MW BFBC Power plant at ACC - Wadi

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SH Flow t/h 75SH Pressure Kg/cm2 65

SH Temperature Deg C 485

BFBC Boiler at PT-IBR Indonesia 3 x 75 TPH

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USAID Test Facility-1986

(90 t/h Hot water)

Combustion Test Rig-1979

0.5 M X 0.5 m

(4,00,000 kcal/h)

FBC Test Facility - 1991

(90 t/h Hot water)

FBC Test Rigs at Trichy

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Municipal Solid WasteShivsankar Ind.,Bangalore

SelCo, Hyderabad

Kiln Char

Sunflag Industries,BandaraWashery Rejects

Tisco, Jamadobha

Fuels Tested

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High Ash coalBellampalli, AP

Mill RejectsParli TPS

Fuels Tested

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Rice HuskRice Mill, Tiruchi

Rice StrawTiruchi

Mustard Crop Residue

Manipal Int., Gurgaon

Biomass Fuels Tested

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Wood ChipsTiruchi

Palm ShellsKerala Electricity Board,

Biomass Fuels Tested

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36

2

26

29

3

1

1

46

6

7

7

9

12

15

Westinghouse-W191

MES-SB30

MES-SB60GE/BHEL-Fr 3

JBE-Fr 5

ALST-MS5001

GE/BHEL-Fr 5

MHI-Fr6

ALST-Fr 6

GE/BHEL-Fr 6

GE/BHEL-Fr 6FA

GE/BHEL Fr 9E

Siemens-V 94.2

GE/BHEL-Fr9FA Fired HRSG Unfired HRSG

3

6

2

26

29

3

1

1

4

6

6

7

79

12

15

Westinghouse-W191

MES-SB30

MES-SB60

GE/BHEL-Fr 3

JBE-Fr 5

ALST-MS5001

GE/BHEL-Fr 5

MHI-Fr6

ALST-Fr 6

GE/BHEL-Fr 6

GE/BHEL-Fr 6FA

GE/BHEL Fr 9E

Siemens-V 94.2GE/BHEL-Fr9FA

Fired HRSG Unfired HRSG

Combined Cycle - 62Cogeneration

Unfired - 9Supplementary Fired - 66Total - 137

ALST-Alsthome Atlantique, France

JBE-John Brown Engg, UK

MHI-Mitsubishi Heavy Industries, Japan

MES-Mitsui Engg & Shipbuilding, Japan

HRSG Experience list

Around 100 HRSGs are

of HARP design

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Two Row Module

Single Row Module

HRSG Module design

improvement

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Module manufacturing Vertical position

For better weld quality

&

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Facility created for largersize HRSG Module

Fabrication vertical

position welding

HRSG Frame assembly

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Standardisation of HRSGs for 9FA GTs

Inlet ductBeam

Bottom brazing

beam

Internal Liner

Inlet duct

HP

IPF

CS

IP LP

Duct

Top brazing beam

Insulation

Main boilerColumn

Modules

HP Drum

IP Drum

LP Drum

HP/IP/LP Drums

Module height

Module width

Heat transfer bundlesdisposition.

Inlet duct configuration

Ducting & Liner system

Insulation system

Structures

Column location and spacing

Floors and stairs

Module support arrangementand hangers

Major components standardised for all 9FA HRSGs

Floor

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CFBC Boiler Design Upgrade

About 50 feedbacks from the operational experience from Surat Lignite(SLPP Phase 1) and BILT Graphics

Learnings from 158 SARs from SLPP I and BILT Graphics incorporated

Discussions with manufacturing and OP & C groups for using ofstandard tooling and materials

Discussions with Erection Group Pre engineering and before

commencement of erection

For 125 MW category

For 250 MW category

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Feedbacks from Operating Units

Lignite Feeder Improvements

Back Sifting of Bed Ash into PA Wind box Back pass Hanger Tube Erosion

FBHE WW Failures - Wall Pitch reduced

AH tube corrosion - Arrangement/Metallurgy

Soot blower at Back pass entry

Welded Flow Orifices for Spray lines

PA and SA ducts NMEJ to MEJ

Cyclone, Feeder Outlet MEJ to NMEJ

Header Connections Changed to avoid Choking

Indigenisation of Refractory, Air-nozzles, Drag Link Chain Feeder, Rotary

Feeder, Vortex Finder

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Backpass Hanger tube Erosion at Entry

o Due to nature of the Duct

connections from the Cyclones

to the common Backpass

preferential gas flow pattern

exists.

o This induces high velocity zones

leading to tube erosion asindicated in the enclosed

transparencies.

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FlueGas

Half Shields

Plan View Convection Backpass Hanger Tubes

CFD Study made and sacrificial Half-shields introduced. Performance

found to be good

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Superheater Header connection change to avoid chocking

Existing Improved

Similar changes in RH and Economiser Headers

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Discussion with Manufacturing Groups

Suggestions Implemented in 125 MW CFBC boilers:

No. ofWW panels reduced from 187 to 148

In-conel attachments in coils replaced by SS Attachments for

easy welding

Combination of T12, T22 & T91 avoided in a single coil to havesingle HT cycle (wherever feasible)

Close pitch drilling of headers eliminated

ID controlled sleeves for coils attachments for easy insertion

Short Radius bends eliminated (Wherever feasible)

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Combustor Panel Openings - improvements

Ease of Panel Manufacture

PresentFuture

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Evaporator circuit close pitch drillingExisting Improved

Similar Improvements made in SH2A, SH2B, RH1, SH3, SH1, Eco, Seal Pot header

connections

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Major issues

Trial assembly of cyclones & match marking at works

Pullout bends of FBHE front panels to be supplied in loose

Erection weld of FBHE coils at about 250 to 300 mm fromwater wall panel

Seal boxes, cyclone, inlet & outlet ducting of cyclone to be fully

welded from inside for better accessibility

Erection Feedbacks Incorporated

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Teething Issues faced and resolved in Giral Phase 1

Leakages of hot ash: Improper seal weldingof pressure parts

were identified and attended to. Procedure evolved and sent toSite to include Protocols for checkingduring erection in Giral II.

Clinker formation at Start-up Burner:ImpingementofHFoilon

burnerthroatcaused clinkers. Resolved bychanging burner tips

with narrower spray angle. HFO was also contaminated withwater - damaged pump barrel, also caused improper combustion

in the burner

Lignite Rotary Air-lock Feeder trips: Frequent feeder trips due to

clutchslipping and resetting of the torquevalue was analysed

andimprovements incorporatedin the clutch assembly and

operating satisfactorily

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Teething Issues faced and resolved Contd.

Foreign material entry into the Lignite feeding system:Foreign

materials like tubes of 2-2.5m longhave found entryinto the

drag chain feedersand damaged theconveyorchain links.

Material hang-up in cyclone: The material buildup in LHS

cyclone was observed on two occassions. After analysis

improvements in operation logics

measurements like seal-pot inlet pressure and

temperature

air injection in cyclone at some critical locations where

material hang up noticed were implemented and the unit

has been in satisfactory operation.

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Limestone size finer:The fines content (

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Issues to be resolved (Customer) - contd.

HFO contaminated with water:The Heavy fuel oil (HFO) used during start-up/load support is contaminated with water and led to improper combustion. The oil pump

barrel got damaged due to water and was replaced. HFO is hence not used in bed lances for

maintaining the load in case of a problem in the Lignite feeding system. Steps taken for reducing

moisture content.

Flue gas analysers :Measurement of CO2 and O2 in order to ensure safe and complete

combustion and SO2 measurement to ensure adequate limestone feeding is yet to beestablished. So far it has been managed with our portable instrument. Presently the instrument

has been calibrated by Vendor and will be observed during operation.

Lignite Drag Chain conveyor trips:Damages of the chain links occurred due to entry offoreign materials. The damaged chain assemblies were stiff. Vendor specialist from UK came to

site, analysed and informed that presence of stagnant wet lignite is the cause. Advised that

lignite is to be drained in case of unit shut down and also lubrication of the chains periodically

to avoid such occurrences. Replaced with new conveyor chain assembly. Failure of Pins noticed

during recent operation, Taken up with Supplier for resolution. Meantime, existing chain

assembly is being replaced with new material supplied for Unit II

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Non Integral FBHE Arrangement 125 MW CFBC design

Integral design Non-integral design

Reduced Shop Weld & Ease of Panel Manufacture

Downcomers (9 nos)

2 nos 457.2 x 40.0

2 nos 355.6 x 30.0

2 nos 141.3 x 16.0

3 nos 219.1 x 22.2

Risers (78 nos)

48 nos 159.0 x 16.0

12 nos 101.6 x 10.0

18 nos 88.9 x 11.13

Supply Pipes (64 nos)

40nos168.3 x 14.27

8 nos 141.6 x 16.0

16 nos 88.9 x 11.13

Downcomers (5 nos)

3 nos 457.2 x 40.0

2 nos 368.0 x 56.0

Risers (58 nos)

58 nos 159.0 x 16.0

Supply Pipes (44 nos)

44 nos 159 x16.0

Use of Standardized

Forged Drum Nozzle

Multi-Cell CLH, Disc Spring & Multi Ball Bearing Supports Eliminated

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Convective Pass Arrangement Reduction in erection joints

10000 x 6800 10871.6 x 6807.2

Section Assy# SL ST

FSH 53 96 203.2

FRH 106 96 101.6

LTSH 106 96 101.6

Eco IV 106 96 101.6Eco III 106 96 101.6

Eco II 106 96 101.6

Eco I 106 96 101.6

Hanger 3x53 203.2

No of Joints 10112 (including FBHE)

Section Assy# SL ST

FSH 55 65/102 180FRH 56 65/96 180

LTSH 110 76 90

Eco IV 110 90 90

Eco III 110 90 90

Eco II 110 90 90

Eco I 110 90 90

Hanger 3x55 180

No of Joints 13252 (including FBHE)

Present Future

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Manufacture & Erection Friendly 125 MW CFB Design Erection

joint reduction

Description Integral design Non integral design Variation

No.of WW headers 251 37 86

No.of WW Panel DUs 297 114 62

Multi cell CLH 36 Nil 100

Convective pass panel bend 1992 Nil 100

No.of joints in

FBHE WW panel 4496 Nil 100

Combustor 2384 2384 No Change

HT coils 13252 10112 24

Others 1027 1027 No Change

Total 21159 13523 36

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Manufacture & Erection Friendly 250 MW CFB Design

Description Proposal

design

Contract

design

Future design

( Suggested)

Variation

Combustor panels 9800 5430 4756 12FBHE RH 1 2500 2160 2160 No Change

Low temperature SH 3000 2880 1440 50

Interstage SH 1 3000 2880 1440 50

Interstage SH 2 3000 2880 1440 50

Steam cooled wall 3300 2700 2560 5

Hanger tubes 4800 3000 2400 20

Final SH 3600 3360 1680 50

Final RH 6000 5760 2880 50

BP Evaporator 5500 5400 3600 33

Economiser 2500 3360 2520 25

Other links 2205 2028 2028 No Change

Total 49205 41838 28904 31

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CFD modeling of ducting for optimisation and for ease of manufacturing.

(Eg. HRSG inlet ducting, Cyclone outlet ducting)

PDMS approach Implemented in Konimabo Nickel CFBC boiler design.

Clashes detected during engineering stage itself.

Modularisation approach To reduce number of erection activities. Care

should be taken for mode of transport

Periodic meeting with site personnel and units concerned apart from pre-

engineering discussion

Interface activities finalisation at 0 date Hyderabad & PEM/Delhi

Importance of proper storage at site and identification of material for easy

retrieval Documentation on lessons learned and documentation for future reference

Enhancing customer awareness on process requirement

Towards bench marking through best practices

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Thank you

Improvement over improvement

Continues with your co-operation ..

2.FBC Engg

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