mgr philosophy

7/31/2019 Mgr Philosophy

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24 May 2012 PMI Revision 00 1

MGR SYSTEM AN OVERVIEW

A CHATTERJEE , SS/MGR


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COAL AVAILABILITY FROM MINESDaily an average of 30,000 MT Coal is required for a

typical 2000 MW Station & for 3260 Station like VSTPP , itis around 52,000 MT/day with 0.66 Sp Coal.Each super Thermal Power Project is linked with aparticular coal mine to meet its coal requirement. Thisparticular Mine is called Linked Mine.

i) For VSTPP, The Linked Mine is Nigahi Mine of NCL.

ii) The present capacity is 11milion Ton/year till dategoing to be 15 Million Ton by 2012)

The required coal for any power station is allotted

through SLC (Short Term Linkage Committee) allocationon quarterly basis i.e for 3 months . This allocation isdecided in periodic Quarterly meeting held at Delhi inconsultation with NTPC,COAL INDIA, CEA ,RAILWAYS,

OTHER POWER SECTORS etc.


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Grade Useful Heat Value(UHV) (Kcal/Kg)

Corresponding Ash%+ Moisture % at(60% RH & 40O C)

Gross Calorific ValueGCV (Kcal/ Kg) (at 5%moisture level)

A Exceeding 6200 Not exceeding 19.5 Exceeding 6454

B Exceeding 5600 but notexceeding 6200

19.6 to 23.8 Exceeding 6049 butnot exceeding 6454

C Exceeding 4940 but notexceeding 5600

23.9 to 28.6 Exceeding 5597 butnot exceeding. 6049

D Exceeding 4200 but notexceeding 4940

28.7 to 34.0 Exceeding 5089 butnot Exceeding 5597

E Exceeding 3360 but not

exceeding 4200

34.1 to 40.0 Exceeding 4324 but

not exceeding 5089

F Exceeding 2400 but notexceeding 3360

40.1 to 47.0 Exceeding 3865 butnot exceeding. 4324

G Exceeding 1300 but notexceeding 2400

47.1 to 55.0 Exceeding 3113 butnot exceeding 3865

Grades of Coal


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Merry Go Round (MGR) system is a NTPC owned, full fledgedRailway system used for hauling Coal from Min end to Thermalpower station.

For transportation of coal from Mine end, Coal Rakes are moved inthe dedicated MGR Circuit of NTPC.

Each coal rake consists of Bottom open Broad Gauge wagons(BOBR) hauled by one/two locomotive. The Rake Size is differentfor different project --for VSTPP the Rake Size is 50 Wagons.

MGR circuit consists of Broad Gauge Track ( i.e 1676 mm gauge)

MGR Track is laid on PRC (Pre reinforced Concrete) Sleepers.

For changing of Rake movement , from one Track to another,

Motor operated Point machine are provided which are operatedfrom different Control stations of MGR Circuit.

Multi Aspect Colour Light Signalling (MACLS) system , with panelInterlocking is provided for the safety of the rake movement fromone station to other.

Railway retired Loco drivers are engaged on Contract basis tooperate MGR Rakes for coal transportation purpose,


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MGR SYSTEM CONSISTS OF MAINLY

1) MGR OPERATING SYSTEM.

2) MAINTENANCE OF MGR ROLLING STOCK.

3) MAINTENCE OF TRACK & SIGNALLINGSYSTEM.

4) COAL CORDINATION & COAL BILLINGACTIVITY.


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24 May 2012 7

MGR OPERATING SYSTEM

Rake loading & Sampling

Loading system consists of a high-speed load- out station

at the mine end called SILO. The capacity of the silos forthe NTPC project varies between 3000 -- 4000 MT.The loading operation of the coal Rake takes place while itis moving under the silo at a speed of 0.8 - 1 k.m. per hr. It

takes appx 1 Min/wagon for loading. The silos are cylindrical and fed by twin belt conveyorsfrom Mine end through a Coal Handling System. For accurate weighing of coal to each wagon, Pre weigh

Hoppers are provided which weighs coal of individualwagons before it is discharged to wagon. After loading sampling is carried out , through randomsamples collected from couple of loaded wagons for

quality analysis.


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After loading & Sampling is over Loaded Rake comes to T/H for

unloading at power house end. Track Hopper is normally of 200-250 m length . Total Number of

Track Hopper varies as per coal handling quantity (For VSTPP,it is 3 nos).

In each placement appx 14-15 wagons are placed forsimultaneous unloading at T/H.

Wagons are provided with bottom discharge hoppers fitted withpneumatically operated automatic door actuating mechanism.

After placing the wagons on the hopper, electrical pulse isgiven to the pneumatic device for opening the bottom doors.

Coal rushes down due to its own weight. When the track hopper is empty, it takes only 20 seconds for

unloading one wagon i.e. 60 Tons. After unloading operation, individual wagon doors are closed,

checked for Proper setting of wagon doors & sent forsubsequent loading.

This coal falls on a T table, over which a paddle feeder runs


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1) TOTAL MGR CIRCUIT IS DIVIDED IN 3 CONTROLSTATIONS.

2) MOVEMENT OF RAKE/LOCOMOTIVE , FROM ONESTATION TO ANOTHER , AFTER GETTING LINE

CLEARANCE THROUGH PRIVATE NUMBEREXCHANGE & RECEIVING SLOT.3) ALL MOVEMENTS DONE WITH SIGNALS ONLY

WHEREEVER PROVIDED.4) STATION WORKING RULE FRAMMED & DISPALYED

AT ALL CONTROL STATIONS.5) ABSOLUTE BLOCK WORKING FOLLOWED DURINGRAILWAY MOVEMENT THROUGH DUDHICHUACIRCUIT ,WHERE ONLY ONE PARTY OPERATES AT ATIME


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1) STRICT ADHERENCE OF STAION WORKING RULE &MOVEMENT THROUGH SIGNALS .

2) REGULAR BRAKE POWER TESTING OF RUNNINGRAKES , AT LEAST ONCE IN A WEEK.

3) SIGNAL OVERSHOOT PROTECTION SYSTEMPERIODICALLY TESTED.4) MONTHLY SAFETY AUDIT THROUGH VSTPP

SFAETY TEAM & TECHICAL AUDIT THROUGHCORPORATE CENTRE TEAM.

5) YEARLY SAFETY AUDIT IS PLANNED THROUGHRAILWAY EXPERTS.6) REGULAR FOOT PLATE INSPECTION BY

DEPARTMENTAL HEAD & OTHER SENIOR OFFICIALS


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WDM2A WDS6 WDG-3A Number 2 4 4

HP 2400 1200 3100

Speed 120 60 100

Tank Cap 5000 Lt 4000 6000

Weight 120 MT 126 MT 112MT

Cost 7Cr 6 Cr 8 Cr


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Type of Wagon BSCL CIMMCO TEXMACO

No of Wagons 43 67 39 +119

Total = 268 Nos

Year of Comg 88-89 90-91 00-01 & 05-06 DOM System Single Link Single Link Double link

Axle Load (Ton) 22.9 22.9 22.9

Length (M) 13.41 13.41 13.41

Carrying Capacity 60 MT 60 MT 60 MT Cost/Wagon Appx 25 Lacs


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LOCO MAINTENANCE

Light Schedule: T1,T2,M1,M2 includingtrouble shooting in MGR Work Shop.

Heavy Schedule: M4 &M6 including

Breakdown Maintenance in MGR WorkShop.

Major Schedule: M 24 & M 48 in Railway

Diesel Shed( like Patratu , E.C.Rly) POH:M 96 at Railway Workshops Golden

Rock(Trichy)


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DETAILS OF WAGON

MAINTENANCE Monthly Maintenance of 4 Rakes (50Wagons)

Maintenance of DOM Systems including

overhauling of Spool Valves.

Maintenance of Brake Systems includingoverhauling Distriubutor Valves.

Wheel Changing. Overhauling/Reclamation of Axle Bearings.

Reclamation of Wagon Doors.


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SIGNAL & TELECOM SYSTEM OF MGR Vulnerable areas of the track are electrically circuited

which are activated by the passage of trains forensuring maximum safety in train operation

Inter slotting system between the Cabins ensuresinvolvement of two Cabins for receiving & dispatchingof trains

Apart from the Signals, communication channelbetween the Control Rooms & Loco Driver isestablished thro Wireless & Walkie Talkie sets.

Signaling system with wireless communication is fullyoperational for safe train movement.

Multi-aspect Color light signaling with motorizedoperation of Points

System is operable from a interlocked Control Panelwith mimic diagrams located in Cabins.

Real time movement of trains are monitored thro Panel.


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ROUTINE S&T MNTCE Maintenance of Secondary cells numbering 300 Nos

Checking & adjustment of Point machines 33 Nos forcorrect setting in Normal & Reverse positions

Maintenance of 50 Nos Track Circuits

Adjustment of Voltage & correct focusing of Signals

Checking of interlocking circuits for propercorrespondence between Panel & Site,

Visual inspection of Relays

Maintenance of Wireless and Walkie Talkie sets

Maintenance of 2 Nos DG sets (for Standby Powersupply)


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SALIENT FEATURES OF MGR TRACK

Length of main MGR coal circuit 19.6 Km.

Total 52 Track Kilometer (including DCH & Non-coal track)

is maintained by MGR/VSTPP

Almost 40% i.e.7.8 Km of main MGR are in curvature

Steepest Gradient 1 in 125 Down in DCH Circuit.

52 Kg rail, short welded rail panel, T-12 rails for main line

and T-18 for yard lines in use.

No of Points & Crossings : 1 in 8 48 nos

1 in 12 03 nos Sleeper density M+7 in main line and M+4 in yard lines. PRC sleepers laid throughout main MGR track Total number of bridges & culverts - 34 Longest being 78 M steel girder bridge at DCH Track.


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ROUTINE TRACK MNTCE

Daily patrolling of the entire track on foot by Key man. Packing of track at locations where slackness found.

Through packing of entire track once in a year.

Lifting of track at required locations.

Overhauling of track. Replacement of worn out rails and sleepers.

Maintenance of Hand lever operated points .

Re-alignment of curvature where distorted.

Lubrication of fish-plated joints yearly.

Greasing of gauge face of curvature track.

Removing spillage coal from track in W/Shop areas .

Drain cleaning & de-weeding along the track.


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MGR VSTPP AT A GLANCE1) TOTAL TRACK LENGTH MAINTAINED(INCLUDING BASKET MINE) =45 Km.

2) MAJOR BRIDGES IN CIRCUIT 2 STEEL GARDER(13 M)- NGH CIRCUIT-- 1 STEEL GARDER(26 M) DCH CIRCUIT-- 1 STEEL GARDER(72 M) DCH CIRCUIT

- 1 RCC GARDER BRIDGE(15 M) NGH CIRCUIT3) STEEPEST GRADIENT 1 IN 125 (IN DCH CIRCUIT)4) LOCOMOTIVES-- WDS6 =4 Nos. WDM2 =2 Nos WDG 3A= 04 NOS(1 ON LOAN BASIS FROM SIPAT)

TOTAL LOCO = 105) WAGONS BURN STANDARD =43 Nos

CIMMCO =67 Nos.

TEXMACO =158TOTALWAGONS =268

6) TOTAL NUMBER OF MOTORISED POINTS IN CIRCUIT = 33 NOS7) TOTAL NUMBER OF SIGNALS IN CIRCUIT = 21 NOS8) RAKE SIZE 50 WAGONS


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MGR PERFORMANCE(07-08) AT A GLANCE

MAXIMUM COAL TRANSPORTED

1) IN A DAY = 70,138.94 MT(31/03/08)

2) IN A MONTH = 17.21 Lac MT(Mar- 08)

3) IN A YEAR = 173.91 Lac MT

(2007-08)


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COAL SUPPLY TO VSTPP DURING

THE YEAR 2007-08

Total Linkage 176.58 Lac MT

Total Receipt 173.91 Lac MT Total Consumption 171.43 Lac MT


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24 May 2012 28

Coal handling system is the arrangement for transferring ofcoal from coal-wagons to coal-bunker or coal stock yard.

It also provide arrangement for separation of material

impurities, crushing of coals, Coal sampling etc.

In the coal handling system of NTPC stations, three coal paths are

normally available

Path A - direct conveying of coal from track hopper to boiler bunkers.

Path B - from track hopper to stockyardPath C - from stockyard to boiler bunkers.

The storage facilities at the stockyards have been provided only for

crushed coal.


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The coal handling system is designed to provide100% standby for all the equipment and conveyors.

The capacity of the coal handling system for super

thermal stations varies from 1200 to 2000 t/h,normally, for a stage of 1000 MW,


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plough feeder/ paddle feeder vibrating screen

crushers,

Conveyor belt,

Idlers, Pulleys,

Drive Unit,

Take-ups,

Skirt board, Scrapper,

Stacker-cum-reclaimer,

Magnetic separators,

Motorized tripper.


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Below track hopper paddle feeder arrangement isprovided to unload coal to coal conveyors.

The 200mm coal as received at the track hopper isfed to the crusher house through 1A & 1Bconveyors.


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Vibrating Screen :The function of the vibratingscreen is: -

To send the coal having size of less than 20mm to

belt feeder through the bypass chute bypassing thecrusher and

To send the coal of more than 20mm size to thecrusher.


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CRUSHERS

To crush the coal from 200mmto 20mm size received

from vibrating screenCrusher hammer are made of MAGNEESE STEEL .

Hammer row -4(stage 1)

(a)Row-1 & 2 =18 hammer each

(b)Row-3&4=20 hammers each

No of hammer in each Crusher-

stage-1 = 76 hammers

stage-2 = 92 hammers

Weight of each hammer=18.5kg

Crushing motor rating -740kw/3.3kv

Life of hammer =4 lac MT of coal

Normal capacity=600 tons/hr


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Normally these crushers have a capacity of around 600

tons per hour.


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CONVEYOR BELTS

Made of diff. Layers or piles of fabric duck with rubber

protected by a rubber cover on both sides & edges.Fabric duck are designed to withstand tension created in

carrying the load .

Nylon rubber cover protect the fabric duck.

Material =fire resistant grade.

Belt Width=1600 mm.

Strength= 1000/1250 kN.

Belt speed=3.2-3 m/s.Belt length=20km.


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IDLERS

Idlers consists essentially of rolls made out of seamlesssteel tubes enclosed fully at each end fitted with

stationary shaft, antifriction bearing and laybrith sealing.

TYPES

TROUGHING IDLERS- shape the belt to support a

moving load without spillage or damage to the belt.

IMPACT IDLERS - absorb the shock of falling material

at loading and transfer points to protect belt from damage


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POSITIVE ACTION TROUGHING TRAINERS

automatically maintain troughing side alignment inone-way conveyors. A center pivot frame and offset

neutral guide rolls provide the troughing action.

RETURN IDLERS

support the empty belt during the return run.

POSITIVE ACTION RETURN TRAINERS automatically maintain return belt alignment on one-way

conveyors.


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PULLEYS

Made of mild steel.

Rubber coating is used to increase friction

factor between belt & pulley (rubber lagging

Shell dia-500mm.

Shaft dia-1400mm.

Pulley length-1800mm.

Shaft length-2350mm(bearing centre to

centre)


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DRIVE UNIT

Motors coupled to reduction gear with the help

of flexible/fluid coupling on the high speed shaft of theGear box

Flexible coupling on the input side

TAKE UPSTake up pulley to facilitates

Necessary tension for the drive to operate the belt

Sag at a point where requires horse power will be

at a minimum and load will move with least

disturbance over idlers


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SKIRT BOARD

Used with chutes at trail end.

Guides material centrally on the belt while loading

until it has settle down on the belt

SCRAPPERS

Placed at discharge pulley in order to clean the

carrying side of belt.It avoids the wear of return idlers due to build up

material.


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Pull Chord

Belt Sway

Zero Speed

Chute block


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This is used for stacking and reclaiming the coal fromstock yard. Generally two stacker claimers have beenprovided at each of the NTPC's projects. Their normalcapacity is 200 tons per hour and maximum design

capacity is 450 tons per hour. The stacker reclaimer generally consists of (a) bucket

wheel or digging wheel (b) boom conveyor. While thebelt conveyor carrying the coal for the stock yard is in thesame direction but the direction of the boom conveyor

with respect to stacking and reclaiming is opposite. Digging Wheel The digging wheel is use for cutting and

lifting the coal from the stock yard to the belt used fortransfering coal from the yard. The above transfer takesplace in case of reclaiming the coal only.


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24 May 2012 PMI Revision 00 44Stacker Reclaimer


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During stocking operation, the coal from the crusherhouse is diverted towards the stockyard conveyor at atransfer point TP2/ TP3. The above conveyor dischargescoal to the boom conveyor through a discharge chute.The boom conveyor, running in the forward direction,

creates coal stacks. During reclaiming, coal from the stock yard falls on the

boom conveyor with the help of the bucket wheel and theboom conveyor, during this period, rotates in backwarddirection. The coal from central chute falls on the

conveyor belts used for transferring the coal from thestock yard. By this way, the coal moves on theunderground conveyor belts connected to the main belts.

A 6.6 KV motor is used for running the stacker-cum-reclaimer and has a cable reeling drum on which flexiblecable is wrapped.


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Coal to/from stock yard

Generally 2nos

Capacity ---200T/hrMaximum---400T/hr

Bucket wheel

Boom conveyor


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RECLAIMER IN OPERATIONSTACKER IN OPERATION

Bucket wheel


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MAGNETIC SEPARATOR

Any ferrous material onthe conveyor will be liftedfrom the moving conveyor.

No Tripping involved.

MS is interlocked withConveyor start up.

When ferrous Metal is

picked up, the MS ismoved from the Conveyor,de-magnatised and themetal piece is removed.

METAL DETECTORAny Metal with an area

of 100 Sq Cm will be

detected.Conveyor is trippedafter detection.

MD is not having

interlock with start up.A sandbag is droppednear the Metal piecefor easy location


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TRIPPERS

To stack material at

desired bunker

Provided with wheels which moves on rails

parallel to conveyor.

Three types

motorized tripper

Belt propelled manually operated tripper

Winch driven tripper


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WEATHERING OF COAL

WHEN COAL IS EXPOSED TO ATMOSPHERE - IT

REACTS WITH OXYGEN - PRODUCTION OF

HEAT - RISE IN TEMPERATURE - OXIDATION

REACTION IS ACCELERATED - NUMBER OFCHANGES IN PHYSICAL AND CHEMICAL

PROPERTIES OF COAL TAKE PLACE - IT IS

CALLED WEATHERING OF COAL.

IMPORTANT FACTORS FOR


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IMPORTANT FACTORS FOR

STORAGE OF COAL

RANK OF COAL

SURFACE AREA

VENTILLATION

COMPACTION

AGE OF COAL

SIZE AND HEIGHT OF STOCK PILES

% LOSS I N CVSI ZE OF COAL

( MM) 1 YEAR 2 YEAR50 75 O. 11 0. 24

12 03 0. 5 1. 0

0. 3 0. 2 1. 0 2. 1


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PREDICTION OF SPONTANEOUS

COMBUSTION

B-M LIABILITY INDEX:

= 21.48M+ 0.98A- 0.62M

2

-0.58MA+ 0.08A

2

+ 10.2WHERE, M=% MOISTURE(AIR DRIED BASIS)

A=% ASH(AIR BASIS)

COALS HAVING B-M INDEX > 80 ARE HIGHLY

PRONE TO AUTO-OXIDATION.


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MANAGEMENT OF COAL STOCKYARD

Proper coal-air interaction to avoid auto- oxidation and

spontaneous combustion.

Close monitoring during march-june.

Design should ensure that for maximum duration of the year, air

strikes the width of the stockpile and not the length.

Freshly mined coals should be stacked and old coal should be used.

Freshly mined coals should not be stacked over old coal.

Stacking of coal layer by layer, with compaction of each layer.


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MANAGEMENT OF COAL STOCKYARD (CONTD.)

Stacking in trapezoidal shape, not in conical shape.Height of stockpile not more than 9-10m (indian coal).

Lumps and fines should be stacked together and compacted.

Before stacking coal should be visibly wet.

Segregation of stockpiles into various segments and relevent records

of period of stacking, quality of coal (cv) should be maintained.

Compaction of finer particles over the bigger particles.


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mgr philosophy

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