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Development of a Condition Based Preventive Maintenance Action for

Coal Handling Plant of Thermal Power Station.

In the onsite operation phase, failures are the main causes of worsenedperformance and degraded reliability. Consequently, an effectivemaintenance is the main approach to failure reduction.

The basic theory of condition Based Preventive Maintenance is to Propose routineinspection to identify any degradation in the integrity of the systems during theirservice life and to provide an early warning in order that remedial action can betaken before failure occurs.

Note :- Assessing the deteriorating condition is necessary to optimize inspectionand maintenance schedules, of Coal Handling Plant to make decisions and to avoidunplanned outages.

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A Basic Layout of Coal Handling Plant

Unloading

StationTransfer House

Crushing &

Screening

Plant

Transfer House Stockyard

Bunker

Transfer House

The Main Objective :-

1. Establishing an alarm level based on variation of a physical parameter.

2. Prediction of impending failures of critical plant components in real time.

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Condition Monitoring Implementations: -

The steps in implementing CBM are :-

1. Divide Plant For Ease Of Maintenance

Unloading Unit

Feeding Unit

Crushing & Screening Unit

Stacking & Reclaiming Unit

Bunkers2. Detection Of Physical Parameters

3. In Service Examination By Using NDT

4. Analysis or Fault Diagnosis

5. Correction.

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Condition Measurement techniques :-

Parameter Instrumentation Position Description

Vibrations Vibration analyzers/data

collectors, hand held overall

meters

Transducer placed in path

of vibration transmission

i.e. bearing housings

Crushers & Pulley

Bearings, Gearbox,

Crusher Rotors

Vibrations Detection meters, Shock pulse

etc.

As close to source of

vibrations.

Crushers & Pulley

Bearings, Gearbox,

Crusher Rotor

Temperature

(Contact)

Thermocouples, RTD Surface or internally

mounted

Crushers & Pulley

Bearings, Gearbox

Temperature(Non-Contact)

Infra red cameras, Pyrometers,Laser Thermometer

Surface Crushers & PulleyBearings, Gearbox

Lubricants

(Condition)

Analytical lab or Portable lab kit Any lubrication sample Gearbox, Fluid Couplings

Lubricants

(Wear Debris)

Spectrographic analysis, On-line

systems Ferrography

Wear Debris in lubricant

used between wear surface

via magnetic plugs

Gearbox, Fluid Couplings

Speed and

current

Relations

Taco generators with current

transformer

Mounted on shafts Fluid Couplings

Current Load cell with Current

Transformer

Below the conveyors and in

panels

Electromagnetic vibrating

feeders

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In Service Examination By Using NDT :-

Parameter Instrumentation Positions Description

Thickness Ultrasonic thickness gagelike Nova TG2

Surface Transfer Chute Liners, Grindingjib of crushers, Conveyor

structures etc.

Thickness Digital Radiography Surface Transfer Chute Liners, Grinding

jib of crushers, Conveyor

structures etc.

Flaw Ultrasonic Flaw Detectorlike Quantam TE

Surface Crusher Rotors; Jack shaft,Grinding jibs; Suspension Bars,

Arms, Sprocket Tiers etc.

Flaw Acoustic Impact Technique Surface Crusher Rotors, Bearings

Flaw Magnetic Flaw Detector

like MD20 Wire Rope

Tester

Surface Wire ropes of Aerial Ropeway

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Limitations

As the plant operating conditions change, it makes it hard to compare the readings andthe data scatter will be more difficult to trend.

Condition based Maintenance may not easily achieve the confidence of maintenance,due to culture, management buy-in, or regulatory resistance.

There needs to be a good balance between training of CBM technicians, goodequipment for monitoring, knowledge of the equipment being monitored, and planthistorical performance.

Be aware of false indications and manage them so as not to discredit the programme.

Data from the programme should be widely accessible.

Although data management is very important, keep it simple so that it takes little timeto get it instituted.

Team work is a requirement for the programme to be successful.

The CBM programme is not an all inclusive programme and must be balanced withother maintenance processes.

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Technical paper on Quality Assured Maintenance Management For Coal Handling

Plant by Makarand Joshi at web site

Technical paper on Development and Implementation of Reliability centeredMaintenance using Vibration Analysis: Experiences at Rourkela Steel Plant byS.Parida, N.R.Kotu, M.M.Prasad Research & Development Centre for Iron andSteel, Steel Authority of India Limited (SAIL), Rourkela Centre.

Technical paper on Maintenance Method For Critical Equipments Of CoalHandling Plant by Makarand Joshi at web site

Technical paper on Application & Implementation of Residual Life AssessmentTechniques For Coal Handling Plant by Makarand Joshi presented in NationalSeminar of The Indian Society For Non Destructive Testing 5-7 December 2002 atChennai.

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Thankyou

Q/A