vt_project final presentation

8/13/2019 VT_Project Final Presentation

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VOCATIONAL TRAINING

IN

ARAVALI POWER COMPANY PRIVATE LIMITED

(A joint venture of NTPC Ltd, HPGCL,IPGCL)INDIRA GANDHI SUPER THERMAL POWER PROJECT

TITLE OF PROJECT-Preliminary study on thermalpower plant and detail study on coal handling plant

DURATION2 weeks

Concerned Coordinator-Sh. J P Rai (DGM Maintenance)

Project report prepared by

Sh. ABIR MUKHERJEE


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Thermal power plant


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Simplified Diagram


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Main Parts of a Thermal Power

Plant


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Boiler


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Boiler

Boiler is a device for generating steam forpower,processing or heating purposes.Boiler isdesigned to transmit heat from an externalcombustion source(usually fuel combustion to afluid) contained with in boiler itself. In the boilerthe water circulates in a controlled way, that is

the flow in the downcomers is controlled by apump called controlled circulation pump.There are different accessories in a boiler.Theseaccessories are following-

1.boiler drum, 2.down comers, 3.water walls,4.superheater, 5.burners, 6.ignitors.In this power plant water tube boiler is used.


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Boiler drum


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Boiler drum

The function of steam drum is to separate

the water from the steam generated in the

furnace walls and to reduce the dissolved

solid contents of the steam to below theprescribed limit of 1 ppm. The drum is

located on the upper front of boiler.


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Feed water heater


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Feed water heater

There are feed water heaters in the thermal

power plant located by the side of turbine. Theseare generally vertical type and turbine bleedsteam pipes are connected to them. There aretwo types of feed water heater, which are LPheater that is low pressure heater and HP heaterthat is high pressure heater. The exhaust steamwhich is drawn from HP turbine, at anyintermediate pressure is passed through HPheater, and similarly , exhaust steam which is

drawn from LP turbine at any intermediatepressure is passed through LP heater tocomplete the regeneration to increase thethermal efficiency of the plant.


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Schematic of Deaerator


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Deaerator

The presence of certain gasses, principally

oxygen, carbon-di-oxide and ammonia,dissolved in water is generally considered

harmful because of their corrosive attack on

metals, particularly of internal corrosion in

boilers, therefore the boiler feed water should befree as far as possible from all dissolved gasses

especially oxygen. This is achieved by

embodying into the boiler feed system a

deaerator unit,whose function is to remove

dissolved gases from the feed water by

mechanical means

S h ti di f


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Schematic diagram of

Steam turbine


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Steam turbine

The steam turbine is one of the most importantaccessories of the thermal power plant. In any thermalpower plant there are three type of steam turbines.Which are high pressure steam turbine, Intermediatepressure steam turbine, low pressure steam turbine. The

high pressure turbine handles steam of pressure 200-250 ksc, and temperature about 540 degree celcius.Exhaust steam of the high pressure turbine is passedthrough reheater, and after reheating it enters intointermediate pressure steam turbine, and then the

exhaust steam of the intermediate pressure steamturbine enters into low pressure turbine, and thenexhaust steam of the low pressure turbine enters to thecondenser.


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Mechanism of turbine

In the turbine there is a pin wheel ,the action of the flowing fluid causes thewheel to rotate. This part of the machine is called the 'Rotor'. In any turbine,the rotor is mounted on a shaft and consists of the 'Sails' or 'Paddles' whichwe will now refer to as 'Blades'. The blades are fitted into a wheel at anangle and are called 'Rotor Blades'. The wheel is then mounted on to theshaft. This arrangement of a single wheel is called 'one stage' or a 'SingleStage Rotor' and does not produce high power. For large processing and

generation plants, very powerful turbines are needed for driving machineslike compressors, large pumps or generators. In this case, 'Multi-StageTurbines' are used. As stated earlier, the energy needed to drive theseturbines, comes from high pressure, superheated steam. In order to get thesteam to pass to the rotor blades, we need a means of directing the steamon to the blades. The piece of equipment used for this is called a Nozzle.As the steam leaves a nozzle, its pressure decreases and its velocity

increases. This high velocity steam jet is directed at the rotor blades and, asin the pin-wheel, the rotor and shaft begins to rotate. As more and moresteam is released on to the blades, the speed of rotation increases.


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Condenser


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condenser

There are two condensers entered to the two exhausters ofthe L.P turbine. These are surface type condensers with

two pass arrangement. Cooling water pumped into eachcondenser by a vertical C.W pump through the inlet pipe.Water enters the inlet chamber of the front water box,passes horizontally through the brass tube to the waterbox at the other end, takes a turn, passes through theupper cluster of tubes and reaches the outlet chamber infront water box. From these ,cooling water leaves thecondenser through the outlet pipe and discharge into thedischarge duct.Steam exhausted from the L.P turbinewashing the outside of the condenser tubes losses itslatent heat to the cooling water and is connected with water

in the steam side of the condenser. The condensatecollects in the hot well, welded to the bottom of thecondensers.

Condensate pump-A condensate pump is a specific type of pump used topump the condensate water


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Cooling Tower


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Cooling Tower

Cooling towers are heat removal devices used to transfer process

waste heat to the atmosphere. Cooling towers may either use theevaporation of water to remove process heat and cool the workingfluid to near the wet-bulb air temperature or, in the case of closedcircuit dry cooling towers, rely solely on air to cool the working fluidto near the dry-bulb air temperature. Common applications includecooling the circulating water used in oil refineries, petrochemical and

other chemical plants, thermal power stations. Cooling towers varyin size from small roof-top units to very large hyperboloid structuresthat can be up to 200 metres tall. In this power plant natural draftprocess is used to cool water. Warm, moist air naturally rises due tothe density differential compared to the dry, cooler outside air. Warmmoist air is less dense than drier air at the same pressure. Thismoist air buoyancy produces an upwards current of air through the

tower. Cooling water pump

This pump helps to enter the hot water into the cooling tower. This pumphandles large volume of water, that is 30000 m3/hr.


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Schematic of

superheater

S h t


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Superheater

There are three stages of superheater

besides the side walls and extended

sidewalls. The first consists of horizontal

superheater of convection mixed flow type

with upper and lower banks located aboveeconomiser assembly in rear pass.

The outlet temperature and pressure of

the steam coming out from thesuperheater is 540c and 157 ksc

respectively for H.P units.


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Function of Reheater


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Reheater

Power plant furnaces may have a reheater

section containing tubes heated by hot flue

gases outside the tubes. Exhaust steam

from the high pressure turbine is passed

through these heated tubes to collect moreenergy before driving the intermediate and

then low pressure turbines. That is the

function of reheater is to reheat the steamcoming out from high pressure turbine to a

temperature of 540c.


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Function of Economiser


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Economiser

The purpose of economiser is to preheatthe boiler feed water before it is introducedinto the steam drum by recovering heat

from the flue gases leaving the boiler. Theeconomiser is located in the boiler reargas pass below the rear horizontalsuperheater. The economiser is

continuous unfinned loop type and waterflows in upward direction and gas in thedownward direction.


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Primary air fan


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Primary air fan

The primary air fan supplies hot air to the

coal mills to dry and convey pulverised

coal to the burners.


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Forced draft fan


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Forced draft fan

The forced draft fan are designed for

handling secondary air for the boiler.

These fan s are located near P.A fan .

This fan supplies air to the boiler.


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Induced draft fan


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Induced draft fan

There are two induced draft fans per boiler

located between the Electrostatic

precipitator and the chimney. These fans

are used for sucking flue gas from furnace.


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Function of

Air preheater


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Air preheater

The air preheater is a device which is used

to recover the heat from the boiler flue gas

which increases the thermal efficiency of

the boiler by reducing the useful heat lostin the flue gas. As a consequence, the flue

gases are also sent to the chimney at a

lower temperature.


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Electric Generator


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Electric Generator

In electricity generation, an electric generator isa device that converts mechanical energy toelectrical energy. A generator forces electriccharge (usually carried by electrons) to flow

through an external electrical circuit. In this plantthe current which is created by the generator is3-phase. The rotor of the generator is coupledwith the shaft of the low pressure turbine. Thereis a exciter also which is used to control the

generator's terminal voltage and the reactivecomponent of the power developed by thegenerator.


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Transformer

T f


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Transformer

The generator is connected to this

transformer by means of isolated bus

ducts. This transformer is used to step up

the generating voltage. The transformer isgenerally provided with some cooling

arrangement.


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How Generated electricity

reached customer


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Water treatment plant


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Water treatment plant

Water treatment plants used in thermal powerplants are designed to process the raw water toa water with very low in dissolved solids knownas demineralised water. No doubt, this planthas to be engineered very carefully keeping in

view the type of raw water to the thermal plant,its treatment costs and overall economics.

Actually , the type of demineralisation processchosen for a power station depends on threemain factors:

The quality of the raw water

The degree of deionisation i.e. treated waterquality

Selectivity of resins.


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Ash Handling System

Coal Seam

Surge Pile

Pulverize (-150)

Overburden

Fly Ash

Flue Gas

Electrostatic Precipitator

Flue Gas

Boiler

Fly AshBottom Ash

SmokeStack

Fly AshBottom

Ash

Electrostatic precipitator-


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p p

An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate

collection device that removes particles from a flowing gas (such as air)

using the force of an induced electrostatic charge. Electrostatic precipitators

are highly efficient filtration devices that minimally impede the flow of gases

through the device, and can easily remove fine particulate matter such asdust and smoke from the air stream. These are generally two plate type

located between boiler and the chimney.

Fly ash collection-

Fly ash is captured and removed from the flue gas by electrostatic

precipitators or fabric bag filters (or sometimes both) located at the outlet ofthe furnace and before the induced draft fan. The fly ash is periodically

removed from the collection hoppers below the precipitators.

Bottom ash collection and disposal-

At the bottom of the furnace, there is a hopper for collection of bottom ash.

This hopper is always filled with water to quench the ash and clinkers fallingdown from the furnace. Some arrangement is included to crush the clinkers

and for conveying the crushed clinkers and bottom ash to a storage site.


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Electrostatic precipitator


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Chimney

C


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Chimney

These are tall RCC structures. The height of

these chimneys vary depending on thelocations. Combustion product gases called fluegases are exhausted to the outside air throughthese chimney. Flue gases are produced when

coal, oil is combusted in a power plant's steam-generating boiler. Flue gas is usually composedof carbon dioxide (CO2) and water vapour aswell as nitrogen and excess oxygen remainingfrom the intake combustion air. It also contains asmall percentage of pollutants such asparticulate matter, carbon monoxide, nitrogenoxides and sulphur oxides


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COAL HANDLING

PLANT


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Introduction

The purpose of the Coal handling plant in a thermal power plant is toProcess raw coal & insure against the irregular supply of coal which isdependent on many players in the Supply chain.

The function of a CHP is to receive ,process, store, feed the Coalbunkers consistently over the entire life of the Power plant.

Coal is received from mines in the form of lumps, the sizes varyingfrom 100mm to 350mm, in two types of wagons through Rail; BOBR

meaning Bogie Open Bottom Rapid discharge & BOXN meaning BogieOpen High Sided Side discharge Wagon.

BOBR wagons are unloaded in Track Hoppers & BOXN Wagons areunloaded by Wagon tipplers.

Coal is then supplied to the crusher house through Roller screens orVibrating feeders to sieve the coal before feeding to the crusher; 20%of the coal that is received is already


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UNIT #1 500 MW UNIT #2 500 MW UNIT #3 500 MW


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`

STACKER RECLAIMER 2

TP 1

TP 2

TP 3TP 14

TP 13

TP

12

TP 18

TP 21

TP 19

TP

11

TP

10

TP 9TP 8TP 7TP 6TP 5

TP 16

TP 15

TP 4

CRUSHER

HOUSE

WT 3 & 4

WT 1 & 2

TP 20

TP 17

STACKER RECLAIMER 1

CONVEYOR 16 A/B

(157)

CONVEYOR 14 A/B

(157)

CONVEYOR 12A

(720)

CONVEYOR 12B

(720)

C 13

A/B

C 3

A/B

C 5A/B (520)

UNIT #1 500 MW UNIT #2 500 MW UNIT #3 500 MW

MCC

1C

WT MCC

1A

MAIN CTRL ROOM

HT SWGR

MCC 1B

CONVEYOR 1 A/B

(283)

CONVEYOR 2 A/B

(415)

C 6 A/B (144) C 7 A/B (107) C 8 A/B (118)

C

9AC

9B

C

10A

C 10B C

11A

C

11B

CONVEYOR 15 A/B

(103)

PENT

HOUSE

ERA SCOPE

TRF SCOPE

LAYOUT OF

COAL HANDALING

PUMPHOUSE C

PUMP

HOUSE B

PUMP

HOUSE A

PENTHOUSE


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Coal Flow Diagram -CHP


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Main Equipments in CHP

Wagon Tippler Side Arm Charger

Apron Feeder

Conveyor System

Transfer Points

Vibrating Screen Feeder Crusher

Shuttle Conveyor

Stacker Cum Reclaimer

Moving Head Assembly

Travelling Tripper Auxiliary Systems

Miscellaneous equipments


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Types of Wagons

GA Drawing


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GA Drawingof Wagon Tippler

W Ti l


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Wagon Tippler

Wagons are Tippled by Wagon Tippler and the

coal is feed to the hoppers.

Data Sheet of


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Data Sheet ofwagon tippler

Side arm charger


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Side arm charger

Side Arm Charger is required to position the

wagons in the cradle of Wagon Tippler for

Tippling Purpose.

agon pp erith Sid h


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g ppwith Side arm charger

Datasheet


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Apron Feeder


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Front view of Apron Feeder

Apron Feeder


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Apron Feeder

Apron Feeder receive the coal from hopper and

it feeds the coal to belt feeder and subsequent

conveyors

Different parts of


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Different parts of

Apron Feeder


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Conveyor Systems

Coal is conveyed through Conveyor Systems

from Wagon Tipplers to Bunkers.


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Drawing of a Typical Conveyor


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Main Parts of a Conveyor System

Pulleys

Drive itemsMotor, Gear Box, Scoop

Coupling

Belt

Idlers

Frames for pulleys and drive items Counter Weight items


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Conveyor Belting System

Conveyor Pulley


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Conveyor Pulley

Conveyor Idlers


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Conveyor Idlers


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Drive items of a Conveyor

Drive consists of Motor, Gear Box and ScoopCoupling


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Scoop coupling


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Crusher House

Typical drawing of a Transfer


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Typical drawing of a Transfer

Point


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Vibrating Screen Feeder

It is working as a sieve. It feeds to bigger lumps

to crusher and smaller lumps to shuttle

conve or.


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Drawing of Vibrating Screen Feeder

Crusher


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Crusher


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crusher


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Shuttle conveyor

It is used to feed the coal in different chute

positions. It moves upon rail.


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Drawing of Shuttle conveyor

S C


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Stacker Cum Re-claimer

Different Parts of Stacker cum


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Different Parts of Stacker cum

Re-claimer

It can stack the coal in the stack yard and it also

reclaims the coal from yard when required

Drawing of Stacker cum


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Drawing of Stacker cum

Reclaimer

PAY LOADER


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PAY LOADER

Moving head


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Moving head

Its function is to feed the coal in two location of

chute

D i f M i h d


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Drawing of Moving head

Drawing of Travelling Tripper


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Drawing of Travelling Tripper

T lli T i


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Travelling Tripper

Its function is to feed the coal in different location

bunkers. It moves upon the structure mounted rail.

A ili S t


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Auxiliary System

Auxiliary systems consists of the followingitems-

Cooling water system

Service water system Drinking water system

Dust suppression system

Dust Extraction system Ventilation system

P h


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Pump house

Cooling water, Service water, Drinking water and

Dust Suppression system is operated by

Concerned Pump Houses

Pump house layout


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Pump house layout

C li W t S t L t


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Cooling Water System Layout

D t S i


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Dust Suppression

Dust Extraction System


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Dust Extraction System

It is situated near Crusher House. Its function is

to extract the dust from concerned equipments.

Miscellaneous Equipments


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Miscellaneous Equipments

ILMS

Metal Detector

Suspended Magnet

Flap Gate with actuator

Coal Sampling System

RPG ROD Gate

Removal/Detection of Metal


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Particles

ILMS & Coal Sampling System


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ILMS & Coal Sampling System

Coal sampling


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p g

Coal Trivia


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Coal Trivia

Grades of coal


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Grades of coal


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Thank you

vt_project final presentation

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