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CUSTOMER

OFFICIALS

WELCOME

TO

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RENOVATION & MODERNISATION (R & M)

OF

BOILER & ITS AUXILIARIES

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Need for R&M

9 Installation Cost per MW is High for New Units

9 Gestation period is high for New Units

9 Boiler components are Designed for a Life of 25-30 years

9 Pressure Parts Failures due to

Service related damages like Oxidation, Corrosion,

Erosion and Creep Fatigue

Abnormal operating conditions like

- More no. of Start- ups & Shutdowns- Lack of proper maintenance

- Operating at high temp. regions

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Need for R&M (Contd.)

9 Deterioration in Coal quality with Lower Calorific value and

Higher ash content Resulting in

Reduced Availability Boiler and its Auxi liaries

Limitation of Milling System

Erosion of Pressure parts, Gas Ducts, AH, ID Fans

Leading to Unforeseen forced outages

9 Reduced load Operation & Poor Availability leading to Low

PLF of units

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OBJECTIVES OF R&MR&M programmes basically aim at achieving :

9 Reduced Forced outages to improve Availabili ty and Reliabili ty of Boiler

9Capacity augmentation / regain of lost capacity

9 Enhanced operational Efficiency

9 Improved Equipment Performance

9 State-of-the-art upgrades

9 Reduced support fuel requirement

9 Wear life improvements of Rotary parts Particularly Mill , ID Fan & AH

9 Meeting latest environmental standards and Pollution Contro l Norms

9 Energy conservation

9 Increased operational Safety

9 Lesser maintenance requirement & time

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R&M PROGRAM OF BHEL FOCUSSES ON

) Reduced Forced outages to improveAvailability and Reliability of Boiler

)Capacity augmentation / regain of lost capacity

) State of the Art Improvements

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AVAILABILITY & RELIABILITY IMPROVEMENTS

)Even at lesser loads targeted PLF can be achieved ifthe Unit Availabil ity is increased

) Can be achieved by

Reducing Pr.parts failures

Minimising Air ingress into the system

Increasing the availabili ty of Auxiliaries

) Cost effective proposal resulting inmajor saving for the Customer

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LOST CAPACITY RESTORATION

) Improving the Performance of the Unit frompresent operating level of 75-80% to 100%

) Major problem is Deteriorated Coal quality

) Fuel preparation system Up-gradations

) Expenditure will be more

) Direct benefit in terms of MW increase

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STATE - OF - THE - ART IMPROVEMENTS

) BHELs In - house R&D efforts to suit IndianCoal conditions

) Can be retrofitted in Older design units

) Units can be run at optimum Efficiency level

) Operation cost will come down

) Higher Safety for Equipment & Man power

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METHOD OF APPROACH

Method of approach & Technology adopted by BHEL are :

) Plant Evaluation

)Thermal Performance Assessment of the unit.

) Residual life assessment of Pressure parts

) Preparation of R&M packages for Replacement, repairs,

modification and upgrades

) Preparation of cost benefits and execution time

) Execution of R & M program

) Evaluate the Performance feedback of the modifications

after R&M

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PLANT EVALUATIONPlant Evaluation mainly focus in the review of the operational history of

the Boiler, with reference to :

)Number of start-up & shutdown (Unit trip data analysis )

) Operation regimes maintained in the Boiler

) Preservation method adopted during major outage periods

) Duration and extent of parameter escalation mainly with

respect to steam temp.

) Operating history and failure statist ics

) Generic problems experienced by the Customer

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THERMAL PERFORMANCE EVALUATION

) Thermal performance test is conducted to assess the

present performance of the unit & its l imitation to achieve

rated parameters

The following tests normally conducted

) The as-run readings at maximum available load to

evaluate the present performance

) The unit operation will be tuned to optimum possible

running condition and then data collected

) Unit performance at part load (60% MCR)

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THERMAL PERFORMANCE EVALUATION (Contd.)

) The data collected is analysed for total thermal performance

behaviour of the Boiler

Possible ways of improving the PLF/efficiency of the unit l ike :

Need for changing surface areas

Identifying Air ingress points etc

Augmenting Fuel firing system capacity reduction of gas

velocity / temp for minimising erosion potential

Adequacy of ESP & ID fans are decided

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RESIDUAL LIFE ASSESSMENT STUDY

RLA study conducted basically to find out :

) The present condition of the Boiler pressure parts

) To determine the remaining left out life

of the pressure parts

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WHERE RLA FIGURES IN

LIFE EXTENSION PROGRAMME (LEP)

PLANT EVALUATION PERFORMANCE

DATA COLLECTION EVALUATION RLA

PROBLEM AREA

IDENTIFICATION

VARIOUS PROPOSALS

FOR LIFE EXTENSION

F DONE IN PHASED

E FULL OUT

ED

B

A

C

K

PERFORMANCE EVALUATION

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PREPARATION OF R & M PACKAGE

) Analysis for finding the root cause of problems and arrive

at feasible technical solution

) Identifying the problem areas affecting the Unit

performance

) Composite package for Revamp, Retrofit & Modernisationof Boiler will be worked out

) The final recommendation will include :

Pressure parts replacements

Fuel firing capability improvements

Need for acid cleaning

ESP improvement

State-of-the-art upgrades etc.

Cost benefit analysis & Pay back period

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BHELS EXPERIENCE IN R&M

BHELs R&M program mainly concentrate in improvements / up--

-gradation of :

) Pressure parts improvement

) Firing system improvements/upgrades

) Milling system improvements

) Boiler Auxil iaries improvements

) Measures for Pollution Controls

) Controls and Instrumentation updates

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PRESSURE PART IMPROVEMENTS

) Redesign of 2nd pass for lower Gas velocity (10m/s) tominimise Erosion potential

) Cassette / baffles, shields for LTSH, Eco & WW screen bendsfor erosion protection

) Modified arrangements for alignment of superheater infurnace

) Additional flexible loops (bends) introduced in SH outlet

headers to improve flexibility) Binder coil / spacer coils redesigned

) LTSH supply tubes and SH screen tubes eliminated byredesigning the 2nd pass

) Improved WW bottom hopper sealing arrangement tominimise air ingress

) Forced drain system for Soot blower piping

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FIRING SYSTEM IMPROVEMENTS

) Ceramic lined PF bends for fuel piping for better wear lifeand less maintenance.

) Wide range coal nozzles for better flame stabili ty

) High energy arc ignitors for oil consumption reduction

) Air cooled non-retractable oil guns.

) Volumetric belt feeder in place of rotary feeder to improve

availability

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MILLING SYSTEM IMPROVEMENTS

) For Bowl mills, state-of-the-art improvements for betterwear life and increased fineness, like mechanical face seal

assembly, stationary vane wheel assembly, ceramic lined classifier

cones etc.

) For Drum mills, modified liners and ball charge for increase in milloutput as well as for increased wear li fe

) Increased down spout size from bunker to feeder to mill for lesserchance of choking

) Larger size mills in place of old mills for getting more coal output

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BOILER AUXILIARIES & OTHER SYSTEM IMPROVEMENTS

AIRHEATERS

) Extended tube design for tubular air-heaters for avoiding entryerosion and air leakage

) Increased thickness tubes for tubular air-heater for better wear li fe

) Corten steel tubes for bottom air heaters to avoid cold endcorrosion

) Automatic leakage control system and infra red fire detection forregenerative air-heaters

DUCTS AND DAMPERS

9 Guillot ine gates for complete isolation for PA fans, ID fans and ESPducting

9 Louvre dampers with special sealing for open / close dampers9 Biplane dampers for complete isolation9

Ceramic tile lining at some portion of duct (ESP inlet) for erosionprotection

9 Redesigned ducting for lesser velocity to minimise ash erosion9 Acoustic insulation for ducts9 Silencers at Fan inlets

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FANS

) Variable frequency drive for reduced power consumption

) Simply supported type PA fans with sleeve bearings

) Replaceable liners for ID application

) Third PA fan for transporting increased coal output from mills

) Third ID fan for improving draft in furnace

ELECTROSTATIC PRECIPITATORS

9Augmentation of ESP to achieve collection efficiencies up to99.98% to meet reduced particulate emission rqte.

9 Better material (904L) for ESP emitting electrode to avoidstress corrosion cracking

9Micro processor based controls (like BAPCON, RAPCON,COMCON) for better ESP management and collection

efficiency

9 Pulsed on/off control for reduced power consumption

BOILER AUXILIARIES & OTHER SYSTEM IMPROVEMENTS

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POLLUTION CONTROL FEATURES

The Pollution control has become stringent world over and also

in India. BHEL is offering as a retrofit for old boilers for the

following system

) Emission level up to 50 mg/Nm3 can be achieved with

BHEL ESPs and retrofits are made for old Boilers.

Layout constraints are also resolved by innovative wayof positioning the additional ESP fields/ESPs.

) For reducing NOx emission, the following new system /

concepts

Over fire air systems

Concentric firing system

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CONTROLS & INSTRUMENTATION UPDATES

) Measures to avoid spurious tripping by

2/3 logic for furnace pressure and drum level

Visible light flame scanner for better viewing

) Micro processor based controls for Burner ManagementSystem (BMS)

) Secondary Air Damper Control system (SADC) for bettercombustion and flame stability

) Conductivity type Electrostatic water level indicator forproper level indication and control

) Acoustic steam leak detection system for early detection of

tube leaks and to avoid secondary damages

) On-line condition monitoring system for Oxygen / Vibration /Water chemistry / Pollution

)Boiler performance Optimisation System

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) Most of the above design features are available as standard retrofitpackage - as component improvement or as system improvements

) All the above retrofits are implemented in number of Power Stations inIndia and Abroad

) During the past 10 years, BHEL has successfully handled, a massiveRenovation and Modernisation (Phase I & II) programme launched by

Government of India, to upgrade operating thermal power stations run by

state electricity boards

) With this background experience of R & M and also the design update andtechnology improvement, BHEL has also very successfully carried out

rehabilitation of a number of boilers supplied by other manufacturers in

India and Abroad

) In 1990, BHEL has obtained a prestigious overseas order fromTNB/Malaysia for the rehabilitation and incorporating gas firing for 12 units

located at 3 places in Malaysia. This contract has been successful ly

completed to the entire satisfaction of the owner and a rigorous

Performance guarantee test carried out

CONTROLS & INSTRUMENTATION UPDATES (Contd.)

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BHELS EXPERIENCE ON STATE-OF-THE-ART DESIGNIMPROVEMENTS

Old Design

) 100lb Volumetric Rotary feeder for feeding raw coal into the Mill

) Feeder speed control by PIV

) Boiler load demand signal actuate PIV for more coal into Mill andBoiler

) Hinge gate mechanism controls the volume of coal fed into the Mill

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PROBLEM FACED

) Coal flow largely depends upon Raw coal size

Presence of foreign material

Bulk density of coal Effective operation of hinge gate

) Shear key & Shear pin failures

) Coal flow is very much erratic

) Low rangeability & variation in output

) Problem with Hinge gate mechanism

) Wear out of PIV gears & chain leading to ineffectivespeed control

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MODIFICATION IMPLEMENTED

) BHELs Belt type Gravimetric feeder

) Existing R.C.Feeder is of short centred type

) BHEL developed short-centred Volumetric Belt feeder with

24 Down spout piping

Eddy current clutch drive

Coal on belt monitor Belt motion monitor

) Robust construction as per NFPA

) Feeder speed control by variation of field voltage to eddycurrent drive

) Bunker emptying can be done by reverse rotation of feeder

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PERFORMANCE AFTER RETROFIT

) These feeders are running continuously for the past 2 years withoutany of the problems

) Uninterrupted coal flow to the feeder and the pulveriser ensured

) Shear key and shear pin failures eliminated.

) Controlled coal flow through the belt type feeder improved therangeability and linearity of coal flow with ref.to speed variation

) Eddy current clutch drive of the new feeder provides accurate &reliable feedback signals for faster response of load change

) Bunker emptying chute in feeder also helps in mtc. of the bunkerduring rainy season

) Coal on belt and belt motor monitor doubly ensures the NO-coal Flowcondit ion and gives immediate signal to the operator

) Higher availability of the unit and better satisfaction levels

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BHEL's Experience in Renovation & Modernisation

1.Domestic Projects(During the period 1990 to 1999)

SL.

No

Name of the

Customer

Name of the Power

Station and Capacity

Nature of Work Carried out Remarks

01 Neyveli Lignite

Corpn.Ltd

(NLC)

4 x 50 MW Unit nos.2, 3, 4

& 5 Boilers of Russian

makeComplete pressure parts replacement (waterwalls),

economizer, downcomer, SH headers, DESH, entire MS

piping etc. about 350 tons).All valves reconditioning/replacement

All non-pressure part renovation

Measures for performance uprating/low capacity

Measures for performance uprating/low capacity

restoration.

Unit loaded to

235 t/hr (design

220 t/hr)

Exit gas

temperturereduced from

190oC to 140oC

02 Steel Authorityof India Ltd.

(SAIL)

Bokaro Steel plant 3x220t/hr Units nos. 3, 4 & 5

Boilers of Russion makePressure part replacement in water wall, screen SH,

Conv.SH, (Platen SH, redesigned with material upgrades)

Burner performance uprating

APH (tubular) performance improvement

Other non-pressure parts renovation

Metal temperature scanner system introduction

Boiler loaded tofull capacity

03 Bihar State

Electricity

Board

(BSEB)

Unit nos. 1-4 & 5-6

8x50 MW boilers

Replacement of complete downcomer pipes

Replacement of waterwall tubes - partial

Replacement of superheater - modified design

Replacement of economizer blocks - modified

Replacement of main steam pipingReplacement of airheater blocks

Work under

progress

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SL.

No.

Name of the

Customer

Name of the Power

Station and Capacity

Nature of Work Carried out Remarks

04 APSEB Kothagudem TPS2 x 110 MW Units Nos.7 &

8

Exit gas temperature reduction by second pass pressure

parts redesign and replacement.

About 50o

C gastemperature

reduction

achieved.

05 RSEB Kota TPS

2 x 110 MWUnit nos. 1 & 2

Lost capacity restoration with fuel system upgrades

HEA ignitor introduction in place of eddy plate ignitor.

Full parameters

achieved since1995

06 TNEB Ennore

2x110 MW

Unitnos. 3 & 4

Complete pressure part re-engineering (tangent tube

waterwall to membrane tube waterwall)

Performance uprating (lost capacity restoration).

Work under

progress

SL Name of the Name of the Power Station Nature of Work Carried out Remarks

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SL.

No.

Name of the

Customer

Name of the Power Station

and Capacity

Nature of Work Carried out Remarks

07 SAIL Bhilai Steel Plant 2x150 t/hr

Non pressure part renovation

Total downcomer/upriser replacement

DESH replacement

SH headers replacement

08 APSEB Kothagudem

2x110 MW

Unit nos. 5 & 6

Complete pressure part re-engineering

(tangent tube waterwall to membrane

tube waterwall

Performance uprating (lost capacity restoration)

Non pressure part renovation

Work under

progress

09 HSEB Panipat TPS

4x110 MW

Unit nos.1,2

Milling system capacity upgradation

Work under

progress

10 UPSEB Obra Unit no.11 200 MW

Mill capacity upgradation

3rdPA fan introduction

Airpreheater sector widening from 52o to 70o

Lost capacity of

boiler restored.

SL Name of the Name of the Power Station Nature of Work Carried out Remarks

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SL.

No.

Name of the

Customer

Name of the Power Station

and Capacity

Nature of Work Carried out Remarks

11 SPC, Kota 2x90 t/hr boilers

Lost capacity enhancement

Higher size mill replacement

Performance review for low-grade coal

Capacity

enhancement by

more than 15%

carried out

successfully.

12 Gujarat Narmada

Valley Fertiliser

Corporation

Bharuch

3 x 180 t/hr VU 40 boilers

Fuel conversion - additional gas firing facility

Forced drain system for soot blowers (State-of-the-art

improvement)

Fuel conversion

implemented and

successfully tested

at full load. Forced

drain system for

soot blowers

supplied and

commissioned.

13 IOC Mathura 3 x 150 t/hr VU 40 boilers

Conversion of boiler for 100% natural gas firing

Conversion

completed and

performance

proved

14 IOC, Haldia 3 x 125 t/hr boilers

Low-NOx burner retrofit

Burner retrofit

completed and

working.

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2.OVERSEAS PROJECTS

SL.

No.

Name of the

Customer

Name of the Power Station

and Capacity

Nature of Work Carried out Remarks

01 Tenga Nasional

BerhadMalaysia

i) TJPS Stage I

2 x 60 MW

ii) TJPS Stage II

2 x 60 MW

iii) TJPS Stage III

3 x 120 MW

Rehabilitation of boilers

Rehabilitation of turbine and generator auxiliaries

Replacement of total station controls and instrumentation

with microprocessor based system.Life assessment and extension survey

Incorporation of natural gas firing facility in three 120 MW

boilers

More than

Guaranteed

Efficiency

achieved.

02 Tenaga Nasional

Berhad, Malaysia

SIPS

2 x 120 MW

Rehabilitation of boilers.Rehabilitation of turbine and generator auxiliaries

Replacement of total station controls and instrumentation

with microprocessor-based system

Life assessment and extension survey

Incorporation of natural gas firing facility in three 120 MW

boilers.

- do -

03 Tenaga

Nasional Berhad,

Malaysia

Prai

3x120 MW

Rehabilitation of boilers

Rehabilitation of turbine and generator auxiliaries

Replacement of total station controls and instrumentation

with microprocessor - based systemLife assessment and extension survey

- do -

SL Name of the Name of the Power Nature of Work Carried out Remarks

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.

No

Customer Station and Capacity

04 General

Electric

Company,Libya

Tripoli West TPS

60 MW boiler (Stein

Industrie, France, make)

Replacement of all bowed waterwalls

Replacement of superheaters, superheater

supports

Revamping of burners

Revamping of ducts and insulation

05 General

Electric

Company,

Libya

Bengazi

8 x 160 t/hr boilers

(Babcock Company

make)

Replacement if waterwalls

Replacement of refractory & insulation

Replacement of burners

Replacement of expansion bellows

Servicing of soot blowers, valves, fuel

pumping and heating station.

Servicing of fans

Replacement of APH elements and servicing

Renovation of controls and instrumentation

Chemical cleaning.

SL Name of the Name of the Power Nature of Work Carried out Remarks

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.

No

.

Customer Station and Capacity

06 General

Electric

Company

Libya

Zuera Desalination

Plant

2x90 t/hr boilers

(IDRO, TERMICI,

Italy, make) Replacement of waterwalls, bank tubes

Replacement of insulation

Replacement of economizer

Servicing of valves , soot blowersServicing of burners

Servicing of fans

Revamping of controls and instrumentation

07 General

Electric

Company

Libya

Dhama TPS

3x120 t/hr boilers

(Babcock, Germany,

make)

Replacement of waterwalls,

Replacement of soot blowers

Replacement of refractory and insulation

Revamping of burnersServicing of valves

Revamping of fuel system equipment

Servicing of fans

Servicing of airpreheaters and element

replacement

Chemical cleaning

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SL.

No.

Name of the

Customer

Name of the Power

Station and Capacity

Nature of Work Carried out Remarks

8 BangladeshPower

Development

Board,

Bangladesh

Siddhirganj1 x 50 MW (225 t/hr boilers)

(CE, USA, make)

Replacement of complete furnace walls

Replacement of complete bank tubes

Replacement of superheater - partly

Replacement of side waterwall headers

Replacement of damaged burnersServicing of entire boiler including fan, APH, safety

valves and other valves.

Replacement of APH seals

Replacement of refractory & insulation

Replacement of water level indicator

Replacement of part-duct and expansion joints

Servicing of controls and instrumentation

Chemical cleaning

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THANK YOU ALL