Rla Descriptive

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Residual Life Assessment and Life Extension Programme in

Utility Boilers BHELs Experience

Dr V T Sathyanathan, M.E., Ph.D.

Additional General Manager / Research & Development

BHEL, Tiruchirappalli 620014

1.0 INTRODUCTION

Thermal power plants form the major portion of the installed capacity in our country

and , there always exist a wide gap between supply and demand of energy. To bridge

this gap , there is a need to set up new plants for which huge financial investments and

long gestation period is required . Indias thermal Power generation started in 1899

with small thermal power plant with stoker fired Boilers. We have then moved on to

30 MW, 60 MW, 110 MW, 200/210 MW and 500 MW unit rating in the last 2 to 3

decades. Indias power requirement is increasing at an exponential rate and is

expected that more than 1,50,000 MW of installed generation capacity will be

required by 2000 AD. This may need very high initial investment to the tune of a few

thousand corers. Combined with this huge financial requirement, the gestation

period for new units are still in the range of 24 to 36 months depending upon the

rating of the units. Hence, there is a need to look at our ageing units and get their

useful life extended. In India about 15 20 % of utility power generation can be taken

as power from captive power generation. Hence to meet the immediate power

demand, the attention is focussed on extending the useful life of ageing power plants .

Rehabilitation of ageing steam generators through life extension program is the most

cost effective method to achieve the extended useful life . The concept of Renovation


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Residual Life Assessment and Life Extension Programme in Utility Boilers BHELs Experience

will help in minimising the gap between supply and demand to some extent.

Remaining life assessment of these units will help in identifying the critical areasthat need refurbishment / replacement , which when carried out will ensure reliable

operation.

Boilers normally designed for a specific life are capable to deliver an extended useful

life because of the conservatism built-in during design stage itself. Pressure part

components operating at high pressure and temperature are prone for service damageslike creep, fatigue or a combination of creep and fatigue. The assessment calls for

certain special techniques over and above the routine requirements like laboratory

analysis by doing destructive testing through sampling and Non- destructive

examination like Ultrasonics , Oxide scale thickness measurement etc., . Special

techniques as detection of hydrogen damage in waterwalls by attenuation method as

well as corrosion damage of pressure part components are employed on a need based

requirement, depending upon the operational history of specific unit.

Assessment programme will help in identifying the components that can be

considered for continued operation , components that need reexamination after

specific interval and components that require modification/replacement so that the

utility can plan life extension activity in a programmed and phased manner. This

enables the owner to stagger the investment necessary for such rehabilitation in cost-

economic way.

Units that have limitation in achieving full load can be specifically addressed in the

rehabilitation programme so as to regain the lost capacity. Certain state-of-the art

improvements in design could also be investigated for implementation to improve the

efficiency of the plant.

BHEL, as a premier Organisation in the Power Sector of India, through our rich


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2.0 RESIDUAL LIFE ASSESSMENT STUDY

As we go into the details of pressure part life assessment, it is worth looking into

material damage mechanisms, which can cause pressure part failures and reduction in

life of the pressure parts.

Pressure parts deteriorate continuously during service due to time dependent

degradation mechanisms such as oxidation, corrosion, creep, fatigue and interactions

of the above. In actual practice, material damage results from interactions of two or

more of these failure causing mechanisms.

Long term overheating Thermal Fatigue


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extent of damage to a component. Hence, independent study of each unit even in the

same station is a basic need to establish the precise status of each component.Various methods of measuring creep life assessment may be classified into two

categories.

- Method based on the operational history in which the expended life of a

component is examined on the basis of operational history and standard

material properties.- Methods based on post service examination and / or testing on the actual

component.

Precise operational data seldom available in practice. Moreover, as the lower bound

stress rupture properties are considered in the absence of precise knowledge of the

material data, operational history based approach leads to pessimistic life assessment.

However, such an exercise would be very useful in identifying the critical component

that require thorough scrutiny.

Post exposure test (PET) comprises of destructive and non-destructive techniques.

These methods require accessibility to the actual component and hence can be taken

up only during overhauls or planned outages.

Destructive test approaches are helpful in arriving at numerical estimates of remaining

useful life. In case of boiler components like superheater tubes destructive testing by

sampling can also be used since it is relatively easier to remove the samples and

reweld with spool pieces, as compared to the headers and steam pipes of boiler.

In case of thick walled components, it is advisable to combine all the NDT

approaches along with replication to study the surface metallography.

The various stepsadopted in pressure part life assessment in involve the following:

* Review of operational history of equipment.

* Anal sis of data records and maintenance/o erha l reports


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2.1 Review of Operational History of equipment:

The operational history of the equipments/boiler is reviewed with reference tonumber and details of startup and shutdown, operational regimes maintained,

duration and extent of parameter escalation especially steam temperature and water

chemistry regimes. This information helps in identifying the extent of deviation

in operating condition from design and consequently the areas to be examined in

detail by destructive/non-destructive methods can be identified .

2.2 Analysis of Data Records and Maintenance / Overhaul Reports :

Observations during planned shutdown provide a wealth of information on

equipment condition / deterioration. Generally this information is utilized by the

maintenance planning division for preventive maintenance and replacement. History

cards covering replacements done during routine maintenance/forced outages

and planned overhauls will be reviewed so that current status of the unit is assessed

and equipment degradation trend formulated.

Analysis of the data along with design review helps in formulating the maintenance

strategy and also in deciding scope of detailed examination.

2.3 Analysis of Failure Records and Reports :

As the main aim of the life assessment study is to ascertain/ extend the life of

components designed with a finite life, the failure records are a basic source of

information for the study. Reports containing detailed metallurgical analysis will

help in evaluating the failures.

Marking up of pressure part failures in the arrangement drawing helps in

identifying the weaker areas. Analysis reports on premature failures can indicate

the deviations in operating conditions or design lacunas that need correction for

extending the life of the components.

2.4 Visual Examination :

Visual examination is carried out to assess material wastage due to oxidation,

erosion/ corrosion problems, fouling conditions of heat transfer surfaces, integrity of


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2.5 Dimensional Measurements :

Essentially thickness and outside diameter measurements form the dimensionalmeasurements. Thickness measurements at critical areas give a measure of

thickness loss over the year due to erosion and corrosion. Outside diameter

measurements are generally employed to determine the swelling (bulging) due to

creep.

2.6 Non-Destructive Examination :

The following Non Destructive Examination ( NDE ) are normally carried out prior

to examination by replica technique.

2.6.1 Liquid Penetrant Examination :

This technique is adopted primarily for detection of cracks or crack like

discontinuities that are open to the surface of a part, like surface porosity, pitting, pin

holes and other weld defects. In principle, the liquid penetrant is applied to thesurface to be examined and allowed to enter into the discontinuities. All excess

penetrant is then removed, surface dried and the developer applied. The

developer serves both as a blotter to absorb the penetrant coming out by capillary

action and as a contrasting background to enhance the visibility of the indication.

2.6.2 Magnetic Particle Examination :

This technique is adopted for locating surface and sub-surface discontinuities like

seams, laps, quenching and grinding cracks and surface rupture occurring on welds.

This method is also used for detecting surface fatigue cracks developed during

service. Magnetic particle inspection helps to detect cracks and discontinuities

on or near the surface in ferromagnetic materials using dry magnetic particle

testing equipment. The testing is done by magnetising at least two mutually

perpendicular direction to ensure detection of defects in all possible orientations.

2.6.3 Ultra-sonic Testing :

By using high frequency sound waves the surface and sub surface flaws can be

detected. Cracks, laminations, shrinkages, cavities, flakes, pores and binding faults

that act as discontinuities in metal gas interfaces can also be easily detected


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2.7.1 Waterwalls :

Waterwall tube samples will be removed from high heat flux zone for evaluatingthe deposit content and constituents of the deposits. Weight loss method is adopted

for calculating deposit content. The need for chemical cleaning will be decided

based on the deposit content and the constituents of the deposit.

The analysis report may include the need or otherwise for

chemical cleaning. Recommendation on solvent for ensuring the effective removal

of the deposit will also be included as per requirement.

2.7.2 Metallurgical Examination of High Temperature Tubes :

The tube samples removed from superheater will be analysed for any

metallurgical degradation in service. Transverse ring segments from the tubes

will be metallographically prepared and examined using light optical microscope up

to a magnification of 500 x.

Carbide morphology and distribution, presence of creep cavities, dimensional

evidence of creep bulging, and tube wall thinning will be evaluated. The oxidescale thickness on steam side surface will be measured and used in estimating the

extent of damage as also the general operating temperature for the running hours.

2.8 In-situ Metallography by Replica Technique :

The high temperature components in utilities when subjected to high stress for a

long time undergo steady changes in transformation of strengthening carbide

phases followed by creep cavitation. This is the beginning of creep or slow

plastic deformation leading to gradual bulging of pressure parts


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The following three distinct stages of creep occur in several alloys. The first stage of

creep occurs in a short period which is transient. The second stage or steady state

creep occurs over a very long duration of several years. The metallurgical changeslike carbide transformation and dispersion occurs. In this stage formation of minute

creep voids along the grain boundary surfaces also accompanies creep deformation.

In the third stage of creep, the creep voids increase in number and size and get

oriented and connected. They generate micro cracks, and the micro cracks connect

themselves resulting in the initiation and growth of macro crack with sudden fracture

in some zones depending on the operating stress at that zone. The replication is the

technique adopted to obtain the microstructure 'in-situ' by nondestructive

metallography. This technique is used in areas where sample removal is difficult

and not viable on cost economic aspects. Figure 2 shows a pictorial representation of

taking replica.

. Figure 2 A pictorial representation of taking replica

As far as the thick walled components like headers and main steam line and hot reheat

lines are concerned, the replica taken are evaluated based on Wedel and Neubauer

classification.

2.9 Remnant Life Determination based on Accelerated Creep Rupture Testing


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2.9.1 Parametric extrapolation:

Specimen from each sample tube will be subjected to a specified stress andtemperature. Time to rupture versus temperature will be plotted and the

extrapolation will be done for the operating temperature to decide the remaining

life.

The assumptions made in the above method are

a) Thickness variation is not considered and hence the operating stress is

assumed as uniform.

b) Metal temperature considered for extrapolation is assumed as constant and

metal temperature increase due to building of oxide scale over a period

is not accounted.

2.9.2 Application Of Life Fraction Technique :

The life fraction rule says that during creep the fractional reduction in life after time

t , at a given stress and temperature is t / tr , where tr is the time to rupture under

the same stress and temperature. The failure would occur when sum of the fractionsof life equals unity.

2.10 Remnant Life Calculation based on Service Temperature :

Tube samples removed from boiler are evaluated for microstructure classification

based on which the service temperature can be evaluated taking into consideration

the operating hours collected from the plant records.

Another method of estimating operating temperature is based on oxide scale

measurement. As steam passes through the tubes at high temperature, the metal

is oxidized. Knowing the operating hours and oxide thickness measured in mils, the

average temperature 't' is calculated .

2.10.1 Calculation of Remaining Life :

Assuming oxidation rates for a specific period , the average stress can be

calculated for the aging duration considered. With average stress value Larsen-

Miller parameter can be calculated for the particular material. With the Larsen-

Miller parameter rupture life can be calculated using metal temperature values.

Fraction of life consumed is the ratio of operating period divided by rupture


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Total Number Of Boilers (As on July 2000)

Power BoilersIndustrial Boilers

BHEL Boilers

In India

In Abroad

Non BHEL BoilersIn India

In Abroad

127

7156

52

42

10

7575

-

The details of assessment and recommendations pertaining to specific three units are

discussed as case studies.

The first case study refers to a boiler supplied to a refinery which was taken up for

study when the unit had clocked about 150,000 hrs. of operation. The findings fromthe study revealed that except for replacement of outlet header of SH the remaining

components were found to be good for continued operation.

The second case study is relating to a reheat balanced draft unit which was taken up

for study after 130,000 hrs of operation. This unit had experienced frequent outages

on account of reheat system. The methodology and the scope was finalised based on

operational history. The findings from the study revealed that most of the

components were found to be good for continued operation and the anticipated life

can be achieved only with for part replacement of hot reheat header and reheater

coils.

The third case study is relating to a reheat, balanced draft unit which was taken up for

assessment when the unit has clocked 110,000 hrs. This unit had forced outages in

platen superheater and in economiser, because of which the utility had done

replacement of the above prior to study. Since this boiler had certain limitations inachieving the rated capacity and also there was a need to improve the boiler

efficiency, the rehabilitation proposal called for measures to take care of the above

aspects over and above the scope identified from the findings of remaining life

assessment study.


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3.1.2 Field Study :

The non reheat boiler operating at temperature below 427 C was checked mainly forintegrity of welds and also for suitability of waterwalls and superheater coils for

continued operation. Though the components are designed for an operating

temperature below 427 C, replication was carried out at SH outlet header

considering the service hours to which the components have been subjected.

The study revealed that the condition of boiler drum , water walls and SH coils are

good enough for continued operation.

The secondary superheater outlet header when examined with fiberscope indicated

presence of ligament cracks in longitudinal section . Few ligaments on the left

extreme were only found to have cracks where as the other ligaments were found to

be having just initiation of cracks.

To bring back the unit in service, it was necessary to replace the header as the crack

size in few ligament locations were beyond acceptable limits. As the unit was nothaving readily a spare header for replacement, it was decided to partly remove the left

extreme portion of the header which had cracks in ligaments beyond acceptable level

and start the unit. The superheater coils pertaining to the removed portion were

retained in position in order to avoid any possible gas laning. The removed portion

of header material was analysed in Laboratory and the lab analysis indicated that the

ligament crack was due to corrosion fatigue. The typical inside view of the affected

header is given in figure-4.


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3.1.3 Laboratory Analysis :The cut piece from SH outlet header was taken up for detailed analysis. The damage

in the ligament location was attributed to corrosion fatigue. Corrosion damage wasseen on inside surface of the header in other locations also. Though the replica taken

from the header parent metal location did not reveal any microstructure degradation,

the material was tested for tensile strength and yield strength which confirmed the

suitability of material for further operation. The hardness measurements carried out at

different locations confirmed no softening of material .

Considering the metallurgical condition of the header and also based on the above

laboratory results, it was decided to keep the unit in service for a limited period with

the old header till replacement is arranged.

The replacement decision was taken considering the corrosion damages seen on

steam side surface of the header which was mainly attributed to collection of

condensate during shut down. No drain provision was available in the original design

and hence the condensate gets collected during shutdown .

The new header supplied was provided with drain arrangement and the utility was

recommended to avoid any collection of condensate during prolonged planned

outage of the unit and also to maintain water regime as per suppliers

recommendation.

Thus the remaining life assessment study carried in the above unit indicated the

possibility for continued operation with the existing components and it was

necessary only to replace part of SH assemblies and the secondary SH outlet headerwith a new header .

3.2 CASE STUDY II.

A 140 MW reheat , balanced draft type unit was taken up for study after a service

period of 130,000 hours . The review of operational history indicated failures in cold

reheat header stub as well as in ligament locations of reheat outlet header. Thescope for assessment was finalised based on the failure history and on the outcome of

discussions with station authorities. The work scope for remaining life assessment

study covered the following.

Detection of hydrogen damage in water walls using attenuation principle.


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4. Reheater Misalignment of coils and low remaining life

5. Cold RH Header Erosion in stub bends

6. Hot reheat header Ligament cracks particularly near the T piece.7. Desuperheater Enlargement of nozzle hole and also cracks in

the liner plates.

8. Piping No microstructure degradation

The boiler which was designed for a maximum evaporating capacity of 450 T/hr was

operating at lower load and with frequent failures in reheater. The deterioration in

calorific value of fuel was the reason for load limitation.

Visual inspection carried out on cold reheat header stubs showed rupture opening at

few locations particularly near bend region.

The ligament space at the header inside surface was checked using fiberscope and

cracks were seen in circumferential ligaments particularly near T piece. ( both sides )

Ultrasonic testing using pulse echo with angle beam probe was done for checking

the ligaments in other locations and for sizing the defect.

The other ligament locations were found to be free from service cracks. The replica

taken covering the weld and the heat affected zone location of the reheat outlet

header revealed that the header material had not undergone any micro structural

degradation. The decision to continue to operate with existing cracks in the ligament

location adjacent to the T piece was carefully done after evaluation of the crack size

and taking into consideration the duration required for arranging replacement.

The header pipe thickness nearer to T piece weld was lower as compared to T piecethickness. The increase in stress at this location is likely to cause an early damage and

any additional thermal stress due to mal functioning of spray system will aggravate

the situation. In view of this, spray system was checked. The reheat steam

temperature control was not proper because of damage to control valve seat.

Till replacement of affected portion of header is carried out, the utility was

recommended to take care of the following aspects.

The spray control valve was recommended for replacement with a new valve.

Thermocouples at cold reheat inlet header and outlet header were installed at critical

locations and the temperatures were recommended to be monitored to avoid undue


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Thus with the remaining life assessment study done in this unit, the utility could plan

for life extension and the life extension programme for this unit could be done only

by part replacement of specific components as identified above thereby theinvestment required for life extension programme could be minimised.

3.3 CASE STUDY III

This case study covers the details of remaining life assessment done in one of the 110

MW units. The furnace construction was of refractory design, the air ingress in the

boiler was more and this was causing poor efficiency in operation. While formulating

the proposal for rehabilitation of this unit, this aspect was also taken into account.

Accordingly, the refurbishment programme included activities to improve boiler

efficiency and also the replacements necessary as identified in remaining life

assessment study

Evaporation - 375 TONS/HR.

SH design pressure - 139 KG/CM2

SH design temperature - 540 CMake - BHEL (Czech design)

Type - Balanced draft/Reheat

Service hours - 110,000.

The utility had carried out replacement of platen SH with modified design as the

unit experienced frequent tube failures in platens. Also the economiser located in

2nd pass was replaced with modified design to minimise failures on account of gas

side erosion.

The major findings from the RLA study are given below:

1. Boiler drum Existing drum found to be in good condition.

2. Water walls Bow observed in different locations.

3. SH & RH coils The SH & RH coils were found to have adequate

remaining life. Alignment disturbed.

4. Platen SH headers The common header connecting the branch headers

when examined by replication, was found to have


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The following major recommendations were given.

Bowed water wall sections to be replaced

Platen common header along with stubs for connecting the branch headers to bereplaced. The details are shown in fig. 6

Alignment band provision for SH / RH coils.

To minimise air ingress, it was recommended to replace waterwalls, horizontal

pass and second pass with membrane / steam-cooled walls. ( Shown in thick line

in fig 5 )

Also existing slag crusher system for furnace bottom ash handling was

recommended for replacement with water impounded hopper to eliminate airingress.

4.0 BHELS Experience In Life Extension Programme

BHEL has been engaged in the design, manufacture and supply of boilers / steam

generators from its manufacturing unit at Tiruchirapalli, since 1963. The range of

boilers supplied by BHEL covers utility boilers from 30 - 500 MW capacities, and

also industrial boilers for Steel plants, Fertiliser plants, Paper industry, Sugar plants

etc. These boilers are capable of firing various fuels and industrial by-products like

black liquor, blast furnace gas, coke oven gas, Corex TM gas, bagasse, rice husk etc.

The design is based on the technical know-how obtained from various leaders in

international market as well that developed through in-house R&D efforts.

BHEL has been updating the boiler design over the years to suit our Indian conditions

as well as the deteriorating coal quality. BHEL is also updating the design of boilers,

by incorporating a number of state-of-the-art technologies and also utilising the

feedback from over 500 BHEL boilers in operation in the country and abroad. These

latest practices are adopted, wherever applicable, on the R&M packages proposed by

BHEL. The list of such major R&M packages carried out by BHEL for the boiler

proper (excluding ESP retrofit / augmentation) is given in Annexure 2. BHEL has

l i d fi / i f h 100 ESP f ili / i


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Remaining Life Assessment plays a vital role . BHEL has gained vast experience in

this field and has rededicated itself to serve the customers by continuously updating

its technology.

5.0 References:

1. CBIP Publication no. 168 : Thermal Power Stations in India

2. Sri K. Rajendran & Dr V T Sathyanathan - BHELs Approach / Experience in

R&M of Boiler & Auxiliaries - Indian Institute of Plant Engineers Conference -

DIU - 1998

3. Dr. V T Sathyanathan & R Rajasekaran - Coal fired Boiler design for Reliability

and Maintainability - Indian Institute of Plant Engineers Conference - Madras

1994

4. P.Nagamanickam , K. Rajendran & Dr. V.T. Sathyanathan - Residual life

assessment of boilers - BHEL s experience - Conference on Residual lie

assessment NTPC, Korba 1999

5. N. Ayodhi - RLA Based Life Extension Programme: BHELs Experience In

Indian Utilities

6. Sri. A.M. Pagedar / CEA / Delhi - R&M of Thermal Units - Its economics -

LIPREX Seminar - Hyderabad

7. Dr V T Sathyanthan & K Sivaraman Residual Life Assessment and Renovation

& Modernisation for Major Equipments of Captive Power Plants BHEL Journal,

Vol. 21 No. 1, Feb. 2000.


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ANNEXURE

BHELs Experience in Rehabilitation & Modernisation

OVERSEAS PROJECTS

Sl.

No.

Name of the

Customer

Name of the Power Station

and Capacity

Nature of Work Carried Out Remarks

01 Tenaga

NasionalBerhad,

Malaysia

i) TJPS Stage I

2 x 60 MWii) 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

GuaranteedEfficiency

achieved.

Power

consumption in

FD/ID Fans

achieved

02 Tenaga

Nasional

Berhad,

Malaysia

SIPS

2 x 120 MW Rehabilitation of boilers.

Rehabilitation of turbine and generator auxiliaries.




Incorporation of natural gas firing facility in two 120 MW boilers.

--- do ---

03 TenagaNasional

Berhad,

Malaysia

Prai3 x 120 MW

Rehabilitation of boilers. Rehabilitation of turbine and generator auxiliaries.




--- do ---

Dr V T Sathyanathan, M.E.., Ph.D.

BHEL, Trichy 62014

Page : 17/22


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Sl.No.

Name of theCustomer

Name of the Power Stationand 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 GeneralElectric

Company,

Libya

Bengazi8 x 160 t/hr boilers (Babcock

Company make)

Replacement of 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.

06 General

Electric

Company,

Libya

Zuera Desalination Plant

2 x 90 t/hr boilers

(IDRO, TERMICI, Italy,

make)

Replacement of waterwalls, bank tubes.

Replacement of insulation.

Replacement of economiser.

Servicing of valves, soot blowers.

Servicing of burners. Servicing of fans.

Revamping of controls and instrumentation.


BHEL, Trichy 62014

Page : 18/22


19/22


Sl.No.

Name of theCustomer

Name of the Power Stationand Capacity


07 General

Electric

Company,

Libya

Dhama TPS

3 x 120 t/hr boilers (Babcock,

Germany, make)

Replacement of waterwalls.

Replacement of soot blowers.

Replacement of refractory and insulation.

Revamping of burners.

Servicing of valves.

Revamping of fuel system equipment.

Servicing of fans.

Servicing of airpreheaters and element replacement.

Chemical cleaning.

08 Bangladesh

Power

DevelopmentBoard,

Bangladesh

Siddhirganj

1 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 burners.

Servicing 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.


BHEL, Trichy 62014

Page : 19/22


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DOMESTIC PROJECTS

(During the period 1990 to 1999)

Sl.

No.

Name of the

Customer

Name of the Power

Station & Capacity


01 Neyveli

LigniteCorpn. Ltd.

(NLC)

4 x 50 MW

Unit nos. 2,3,4 & 5Boilers of Russian make

Complete pressure parts replacement (waterwalls,

economiser, downcomer, SH, SH headers, DESH, entireMS piping etc. about 350 tons).

All valves reconditioning / replacement.

All non-pressure parts renovation.

Measures for performance uprating/low capacity

restoration.

Unit loaded to 235 t/hr

(design 220 t/hr). Exit gas temperature

reduced from 190C to

140C.

02 Steel

Authority ofIndia Ltd

(SAIL)

Bokaro Steel Plant

3 x 220 t/hrUnit nos. 3,4 & 5

Boilers of Russian make

Pressure part replacement in waterwall, 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 to full capacity.

03 Bihar State

ElectricityBoard

(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 economiser blocks - modified .

Replacement of main steam piping.

Replacement of airheater blocks.

Work under progress.


BHEL, Trichy 62014

Page : 20/22


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SlNo.

Name of theCustomer

Name of the PowerStation & Capacity


04 APSEB Kothagudem TPS

2 x 110 MW

Unit nos. 7 & 8

Exit gas temperature reduction by second pass pressure

parts redesign and replacement. About 50C gas

temperature reduction

achieved.

05 RSEB Kota TPS

2 x 110 MW

Unit nos. 1 & 2

Lost capacity restoration with fuel system upgrades

HEA ignitor introduction in place of eddy plate ignitor.

Full parameters achieved

since 1995.

06 TNEB Ennore

2 x 110 MW

Unit nos. 3 & 4

Complete pressure part re-engineering (tangent tube

waterwall to membrane tube waterwall).

Performance uprating (lost capacity restoration).


07 SAIL Bhilai Steel Plant

2 x 150 t/hr

Boilers of Russianmake

Non pressure part renovation.

Total downcomer /upriser replacement

DESH replacement. SH headers replacement.

08 APSEB Kothagudem

2 x 110 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.


09 HSEB Panipat TPS

4 x 110 MW

Unit nos. 1,2

Milling system capacity upgradation. Work under progress.


BHEL, Trichy 62014

Page : 21/22


22/22


SlNo.

Name of theCustomer

Name of the PowerStation & Capacity


10 UPSEB Obra Unit no. 11

200 MW Mill capacity upgradation.

3rd PA fan introduction.

Airpreheater sector widening from 52to 70.

Lost capacity of boiler

restored.

11 SFC, 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

3x180 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

3x150 T/Hr VU 40

Boilers Conversion of boiler for 100% natural gas firing. Conversion completed and

performance proved.

14 IOC, Haldia 3x125 T/Hr Boilers Low NOx burner retrofit. Burner retrofit completed and

working.


BHEL, Trichy 62014

Page : 22/22

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