Coal handling plants are used in thermal power plants to handle and process coal. The processed coal in used in the boilers to generate steam. The heated steam is used to run turbines. The turbines moves the generators which in turn produce electricity.

1. COAL HANDILING PLANT
PREPARED BY
PAWAN SINGH

2. INTRODUCTION
COAL HANDLING PLANT
 Coal handling plants are used in thermal power plants to handle and
process coal. The processed coal in used in the boilers to generate
steam. The heated steam is used to run turbines. The turbines
moves the generators which in turn produce electricity.
 Coal being a very brittle and cumbersome material to handle,
requires a sophisticated handling mechanism. This requirement
gave rise to the development of Coal Handling Plants.
 Coal is hard black or dark brown sedimentary rock formed by the
decomposition of plant material, widely used as a fuel.

3. TRANSPORTATION OF COAL
 Coals are generally transported by wagons (trains) from coal
mines to the power plants.
 Coal is received from mines in the form of lumps, the sizes varying
from 100 mm to 350 mm, in two types of wagons through Rail;
BOBR meaning Bogie Open Bottom Rapid discharge & BOXN
meaning Bogie Open High Sided Side discharge Wagon.
 Mostly E and F grades coal are used in India.
 3 ways of transportation of coal is
1) Railways
2) Ropeways
3) Roadways

4. COAL HANDLING PLANT PROCESS SYSTEM
 Coal is received from mines.
 CoalWeighing System
 Unloading System
 Conveyor System
 BeltWeighing System
 Magnetic Separator/ Metal Detector
 Bin/chute vibratory system
 Crushing system
 Feeding system
 Stacking system
 Fire fighting system
 DFDS (Dry Fog Dust Suppression System)
 Dust extraction system

5. COAL FEEDING
 The size of coal lumps is about to the 600mm.
 This coal is fed to single rotary crusher and after that the size
become 300mm.
 This coal is again fed to the double rotary crusher and the size
become 80mm.
 The coal is again fed to the crusher and the size becomes less
than 20mm or 20mm
 Then this coal is fed to the coal mill for pulverization.
 Even when the bunker is full this coal is used for staking or storage
of coal in coal storage area.

7. GENERAL LAYOUT OF CHP
LOADED
COAL
WAGON
TIPPLER
CONVEYORS
VIBRATING SCREENS
CRUSHERS
FEEDER
CRUSHER HOUSE
CONVEYOR BELTS
BUNKERS
MESH OF 250X250 MM
HOPPER
UNLOADED
COAL

8. CATEGORIZATION OF COAL
Grade
Useful Heat
Value (UHV)
(Kcal/Kg) UHV=
8900-138(A+M)
Corresponding
Ash% + Moisture
% at (60% RH &
40OC)
Gross Calorific
Value GCV
(Kcal/ Kg) (at 5%
moisture level)
A Above 6200 Above 19.5 Above 6454
B 5600 -6200 19.6-23.8 6049 -6454
C 4940 -5600 23.9-28.6 5597 -6049
D 4200-4940 28.7-34.0 5089-5597
E 3360-4200 34.1-40.0 4324-5089
F 2400-3360 40.1-47.0 3865-4324
G 1300-2400 47.1-55.0 3113-3865

9. COAL PROPERTIES
 Hardness index 45-50
 Density 0.8MT/m3
 Size 250mm
Parameter
Indian
Coal
Indonesian
Coal
South
African
Coal
Moisture 5.98 9.43 8.5
Ash 38.63 13.99 17
Volatile
Matter
20.70 29.79 23.28
Fixed Carbon 34.69 46.79 51.22

10. OPERATIONAL CYCLE
 BUNKERING CYCLE
 STAKINGCYCLE
 RECLAIMING CYCLE

11. STACKING CYCLE
VIBRATING SCREENS
CRUSHERS
BUNKERING
CONVEYOR
BELTS
COAL FROMWAGONTIPPLER
BUNKERS
STAKING CONVEYOR BELTS
CRUSHEDYARDS

12. RECLAIMING CYCLE
VIBRATING SCREENS
CRUSHERS
BUNKERING
CONVEYOR
BELTS
COAL FROMWAGON
TIPPLER
BUNKERS
STAKING
CONVEYOR
BELTS
CRUSHEDYARDS
OUTER SOURCE
OF COAL IS NOT
PRESENT
NON CRUSHED
YARD
RECLAMING
CONVEYOR
BELTS

13. WAGON TIPPLER
 Tippler is used for emptying the loaded wagons by tipping it.Tippler
retains wagon from top as well as from side by using clamping devices
provided on it. Apart from that track stops, wheel grippers and different
type of limit switches are provided as features of wagon tippler.
 Tippler is driven by either Hydraulic drive or by electro-mechanical drive
or Hydro Mechanical Drive .
 Placement of wagon, on tippler platform, is accomplished by wagon
marshalling equipment like Side Arm Charger or Pusher Car depending
onType ofWagonTippler application.
 These are used to unload the coal wagons into the very less time
(20wagons/hr. or more).
 Weighting of the coal is carried out at wagon tippler.
 Normally 55-60 metric ton coal come in each region.

14. COAL UNLOADING
HOPPER- Coal is transported to the
plant in bottom discharge wagon
rakes and shall be unloaded on
hopper.
WAGON TIPPLER-Tippler is used for
emptying the loaded wagons by
tipping it. Tippler retains wagons from
top as well as from side by using
clamping devices provided.

15. Side Arm Charger is used for hauling rake of wagons, placement of wagons on
tippler table and evacuation of empty wagons from tippler table
SIDE ARM CHARGER

16. COAL UNLOADING FROM WAGONS BY
USING WAGON TIPPLER

17. UNLOADING OF COAL FROM RAIL WAGON
Coal Unloading Hopper

18. CONVEYOR SYSTEM
DEFINITIONS
 Flat belt conveyor: A conveyor having a moving flat belt carried on free
running Rollers
 Troughed belt conveyor: A conveyor composed of a moving belt carried
on horizontal
 Head pulley: The terminal pulley at the discharge end of the conveyor.
 Tail pulley: The terminal pulley at the loading end of the conveyor.
 Snub pulley: The pulley used to increase the arc of contact of the belt on
the driving pulley.
 Carrying idler: Idler roller which supports the loaded belt.
 Return idler: Idler roller which supports the empty side of the belt.
 Bend pulley: A pulley used to change the direction of the belt in a
vertical plane.
 Take-up pulley: The tensioning pulley used in the take-up device which
applies tension to the belt and reduces slack.

19. CONVEYOR SYSTEM
Conveyor Belt transfer of coal in thermal power plant including
carrying of coal from unloading point to the storage site.

20. PIPE CONVEYOR BELT

21. CONVEYOR BELT DRIVE SYSTEM
BELT SPEED
SPEED BEFORECRUSHER:- 2.4 M/SEC
SPEEDAFTER CRUSHER:- 2.7 M/SEC

22. SAFETY SYSTEMS IN CONVEYORS
 PULL CHORD SWITCH
 CHUTE BLOCK SWITCH
 ZERO SPEED SWITCH
 BELT SWAY SWITCH
 METAL DETECTOR

23. Pull cord switch also known as Rope Operated Emergency switch is used as a safety switch
to stop the conveyor belt in case of an emergency. It is also known as pull switch cord.
PULL CHORD SWITCH
PULL
CHORD
SWITCH
PULL
CHORD
SWITCH

24. CHUTE BLOCK SWITCH
Tilt switch is an electronic device specially developed for sensing the level of an
approaching stockpile on stacker-reclaimed or material in a hopper, in a silo and to provide
an output signal which can be used to initiate control actions.
CHUTE
BLOCK
SWITCH
CHUTE
BLOCK
SWITCH

25. ZERO SPEED SWITCH
It is used to monitor speed of conveyors, crushers, rolling mills, agitators,
mixers, stirrers, screw conveyors, and other industrial machinery. This device
actuates relay contacts at preset speed. Using these contacts desired control
action such as zero speed protection/ under speed protection/ over speed
protection can be achieved.

26. BELT SWAY SWITCH
The switch allows smooth running of the conveyor and protects it from damages by over
swaying which can occur due to uneven loading of material, worn out idler roller bearings
etc. Belt sway switch is also known as Run Off Switch.
BELT
SWAY
SWITCH
JBPULL
CHORD

27. METAL DETECTOR
 Metal detectors are used to detect tramp metal pieces from the raw material
coming on the conveyor belt. metal detectors are used to prevent damage to the
processing machinery like crushers, cutting machines, cutters, mills, rollers, saws,
presses, chippers and other processing machinery.

28. VIBRATORY SCREEN
Crush house by conveyor belts where it is crushed to small pieces of about 20 mm
diameter.The crushed coal is then transported to the store yard. Coal is transported to
bowl mills by coal feeders.

29. Emergency Brake
Pedestal Bearing
coupling Gear box
MOTOR CONNECTIONS

30. SHUTTLE CONVEYOR
Shuttle conveyor is a piece of belt conveyor mounted on a travelling trolley, with long travel
drive for smooth, to and fro motion on rail. Easy and trouble free operation ensures long life
to the equipment resulting in efficient performance of the entire plant. It is used for feeding
material at a desired position on bunkers.

31. CRUSHERHING SYSTEM
 In the crusher there is high-speed 3-phase induction
motor which is used to crush the coal to a size of
50mm so as to be suitable for milling system.
1. Ring granulator
2. Primary crusher/beaker
3. Rotary crusher
4. Double roll crusher
5. Impact crusher

32. DOUBLE ROLL CRUSHER
Double Roll Crushers are equipped with two identical crushing rolls rotates towards
each other. Double-Roll-Crushers are used for the crushing coal. Due to the low
crushing ration double roll crusher is producing a product size distribution with less
content of fines

33. IMPACT CRUSHER
ROTOR
COAL
HAMMERS HAMMERS
Impact Crushers starting from the base working principle that compression is the
forcing of two surfaces towards one another to crush the material caught between
them by Impact Hammering.

34. RING GRANULATOR
Ring Granulator type crushers are provided to crush the coal generally from
250 mm/100 mm size to 20 mm size.

35. FLAP GATES
These are used to channelize the route of coal through another belt in case
the former is broken or unhealthy.The flap gates open let the coal pass if
the coal is passed.

36. OPERATION OF CHP
General Instructions
 Before starting the plant, check which of the equipment is available and
accordingly plan an appropriate path for the movement of coal.
 Ensure that the path so planned, is clear for coal movement i.e. Flap Gate
position, Interlocking etc.
 Before starting any equipment ensures that the equipment is not subject to a
P.T.W.
 Check from each location that the equipment is ready for start and no persons
are working on the equipment.
 Line up the system by starting each equipment from the last conveyor in the up-
stream path.
 Good communication between the control room and different equipment
locations is essential before starting the system.
 Ensure that all Metal Detectors and Magnetic Separators are working properly
on running conveyors and foreign material removed, where necessary.
 Adequate lighting should be ensured in all the areas.

37. OPERATION OF CHP
Ensure that all Electrical systems are healthy and all the
protection systems mentioned below are in service.
1. Hooters.
2. Emergency Push Buttons
3. Pull Cord switches
4. Zero-speed switches
5. Belt sway switches
6. Chute block switches
7. Crusher bearing temperature & vibration-monitoring
equipment
8. Interlocks
9. PA System
10. Magnetic Separators
11. Metal Detectors
12. Electro Magnetic/Thrust Brakes installed in long conveyors

38. OPERATION OF TRIPPERS
 Trippers are provided on coalbunkers to receive coal from the
conveyors and feed it to the bunkers. The tripper is mounted on rails
and feeds coal to the bunkers for use on all the units.
 The following checks are to be carried-out before taking the tripper
into service:
a) The availability of supply.
b) That the brakes are clean and functioning correctly.
c) The tripper discharge chute is free from jamming/blockage.
d) That the CRD cable is free from any obstruction and is
tensioned correctly.

39. OPERATION OF CONVEYORS
 Various conveyors are provided for transporting the coal from Track hopper to
Bunkers.
 The following precautions are to be taken before taking any conveyor into service:
a) There is no oil leakage at gearboxes / fluid couplings and the oil
levels are correct.
b) The Discharge and Receiving chutes are free from jamming and
choking.
c) The Flap Gates are in correct positions.
d) All inspection doors are in the closed position.
e) All pull-cords are reset and the EPB is released and ensure that all
protections are healthy.
f) The Alarm Siren is in working order.
g) Communication facility is available.
h) The lighting is adequate.
i) No Permit To Work (Isolation) is pending against that conveyor.

40. OPERATION OF CRUSHERS
 Ring Granulator type crushers are provided to crush the
coal generally from 250 mm/100 mm size to 20 mm size.
The following points need to be checked before returning
any crushers to service:
a) The crusher shall be clear from any jamming.
b) All inspection doors are in the closed position and
locked.
c) There is no leakage at gearbox and fluid couplings
and the oil levels are correct.

41. OPERATION OF PADDLE FEEDERS
 The Paddle Feeders feed the coal on the conveyor belt from the Track
hopper at a controlled rate. The paddle blades projected in the hopper slot
scoop the coal from hoppers and discharge it on the conveyor belt running
below.
 The following points need to be checked before taking any paddle feeder
into service.
a) The paddle arms are free from any obstruction.
b) There is no leakage at gearboxes and fluid couplings and the oil levels are
correct.
c) There is no leakage of hydraulic oil, in the case of hydraulically driven
paddle feeders, and the oil levels are correct.
d) The cable reeling drums for correct winding and unwinding.
e) The paddle feeder is operating only in interlock mode.

42. OPERATION OF STACKER RECLAIMER
 The Stacker reclaimer is provided to stack the excess coal received from the mines
and to reclaim the coal, as and when required.
 The following points need to be checked before returning Stacker reclaimer into
service:
a) The track is clear of obstructions.
b) There is no leakage from gearboxes, fluid couplings &hydraulic system.
The oil levels are correct.
c) The availability of power supply is checked.
d) All operations e.g. travel; slewing etc. are available.
e) Brakes are clean and functioning correctly.
f) CRD cable is free from damage and any obstruction and is tensioned
correctly.

43. PROTECTION
 Belt & following system except crusher will trip in case of
operation of BSS
 In case of excessive belt slippage, low speed due to
over load or otherwise, belt not running although motor
running, belt snapped than belt and following system will
stop through zero speed switch.
 Overloading of more than 600T/hr
 Motors are protected against over load, short circuit,
single phasing.

44. PAWAN SINGH
Mechanical Engineer
THANKYOU