✅ What is CHP? CHP (Combined Heat and Power) is a highly efficient process that generates electricity and captures the usable heat that is produced in the process. Instead of wasting the heat generated during electricity production, CHP systems reuse it for heating or industrial processes. 🏭 Where is CHP used? Industries (chemical, paper, cement, steel, sugar mills) Hospitals Universities Commercial buildings District heating systems ⚙️ How Does CHP Work? (Step-by-Step Process) Here’s how a typical CHP system works: 1. Fuel Input CHP systems use fuels like: Natural gas (most common) Biomass Coal Oil Biogas Municipal waste 2. Electricity Generation A prime mover (like a gas turbine, steam turbine, or reciprocating engine) converts fuel into mechanical energy. This mechanical energy drives a generator to produce electricity. 3. Heat Recovery Instead of wasting the heat from exhaust gases or cooling systems, a Heat Recovery Unit (like a Heat Recovery Steam Generator – HRSG) captures it. This recovered heat is used to: Produce steam Heat water Provide space heating Support industrial processes 4. Heat Utilization The captured heat is then: Piped to nearby buildings or factories Used in heating systems (like radiators) Utilized in drying, sterilizing, boiling, or other thermal applications 🔄 CHP Working Flow (Simple Diagram Description) arduino Copy Edit Fuel (Gas/Biomass) → Engine/Turbine → Electricity ↓ Waste Heat ↓ Heat Recovery System ↓ Steam/Hot Water for Heating or Process Use 🎯 Key Components of a CHP Plant Prime mover – Gas turbine, steam turbine, or engine Generator – Converts mechanical energy into electricity Heat Recovery Unit – Captures exhaust heat Control System – Balances power and heat demands Fuel supply system – Ensures uninterrupted fuel flow 💡 Types of CHP Systems Type Description Example Use Topping Cycle Electricity generated first, then heat recovered Most industrial CHP Bottoming Cycle Heat used first (e.g., in kilns), then residual heat used for electricity Cement, glass industries Packaged CHP Pre-assembled small units Hospitals, schools Micro-CHP Very small-scale (1–10 kW) for homes Domestic buildings 📈 Efficiency and Benefits 🔋 Efficiency Traditional power plants: ~35% efficient CHP systems: up to 80–90% efficient ✅ Benefits of CHP Saves energy and fuel Reduces electricity bills Reduces carbon emissions Provides energy security (can run off-grid) Reliable backup in critical facilities ❌ Limitations of CHP High initial cost Requires steady demand for heat Maintenance and skilled operation needed Not suitable for all building types 🧠 Real-World Example Sugar Mills in India use bagasse (sugarcane residue) to fuel boilers that: Produce steam for processing sugar Generate electricity for internal use and sometimes for sale

2. • Coal, oil, gas and hydroelectric potential
constitute the conventional sources of electricity
generation.
• India is ranked third in the world with respect to
coal reserves (7 % of the world’s total Coal reserves).
• Coal production increased from 30 million tonnes
from 1950 to over 500 million tonnes in 2005 - 2006.
• Seventy percent of the total coal produced is utilised
for power generation. Steel & cement are the other
major consumers.
COAL AND ENERGY SCENARIO

3. Source wise Power Generation
(1999)
Source
Source India
India Japan
Japan U.S.
U.S.
Coal
Coal 59.2%
59.2% 21.2%
21.2% 51.8%
51.8%
Oil
Oil 13.9%
13.9% 16.6%
16.6% 03.1%
03.1%
Gas
Gas 06.3%
06.3% 22.1%
22.1% 15.7%
15.7%
Nuclear
Nuclear 02.5%
02.5% 30.0%
30.0% 19.9%
19.9%
Hydro
Hydro 17.8%
17.8% 08.2%
08.2% 07.4%
07.4%
Others
Others 00.3%
00.3% 01.9%
01.9% 02.2%
02.2%

4. FUEL REQUIREMENT FOR NTPC- VINDHYACHAL
Coal requirement
 The Main input for a Thermal power Station is
COAL.
 After Light-up when sufficient heat is attained in
the Boiler, Pulverized Coal firing is done.
 The average coal requirement per day is Approx.
50,000 – 55,000 MT for Stage I,II & III.

5. CLASSIFICATION OF COAL BY UHV
GRADE Calorific value range
(kcal/kg)
A >6200
B 5600-6200
C 4940-5600
D 4200-4940
E 3360-4200
F 2400-3360
G 1300-2400

6. COAL ANALYSIS
PROXIMATE ANALYSIS
 MOISTURE CONTENT
 ASH CONTENT
 V M CONTENT
 FIXED CARBON
ULTIMATE ANALYSIS
 CARBON
 HYDROGEN
 NITROGEN
 SULPHUR
 OXYGEN
 MINERAL MATTER
 TRACE METALS

8. • Merry Go Round (MGR) system is a private, full fledged
Railway system of NTPC used for hauling the required
Coal from Mines to its Thermal power plants.
• At NTPC - VINDHYACHAL we have Ten Diesel
Locomotives and 5 rakes for the transportation of
Coal from Nigahi & DCH Mines.
• Each coal rake consists of 47 wagons hauled by one
locomotive.
• Modern Multi Aspect Colour Light Signalling (MACLS)
system with panel Interlocking is provided for
the safety of the rake movement
• Daily on an average around 60,000 MT of Coal is
being transported through this MGR System

9. Main feature of MGR
• Loop length 19.6/25km (Nigahi / DCH)
• Traffic density 18 rakes/day (AVG.)
• Cycle time (track hopper to track hopper)
Nigahi Rake 3 hr 15 min
DCH Rake 4 hr 15 min
• Avg loading time at silo is 50 min
• Avg Unloading time at track Hopper is 1.5-2.0 hrs

10. Locomotives & Wagons
 At silo coal is loaded in the
wagons when the rake is on
the move at a speed between
0.8 – 1 Km/hr.
Avg. Loading time: 47-50
min
Locomotives :
Type -WDS6 & WDM2
Nos.- 10

11. COAL LOADING
 At SILO, Coal is loaded in the Wagons
 Capacity 3000/4000 MT (Nigahi /DCH)
 Filling rate 3000 TPH
 Location Nigahi /DCH SILO
 AVG Loading Time at SILO - 1 hr
 Equipped with pre weighing system

12. SILO

13. Loading

14. COAL UNLOADING
 At NTPC end, Coal is unloaded in the Track hoppers.
 Three Track Hoppers, each of capacity 3000 MT
 Coal evacuation rate 2000/1500/1500 MT/H (St-1/St-2/St-
3)
 After placing the wagons on the hopper, electrical pulse
is given to the wagon for opening the bottom doors.
 Coal rushes down due to its own weight.
 When the track hopper is empty, it takes only 20 secs
for unloading one wagon i.e. 60 Tons.
 This coal falls on a ‘T’ table, over which a paddle feeder
runs and pushes the coal on to a conveyor.

15. Nos.: 5*47 + 10 = 245
Type-Bottom opening & Bottom
reclose (BOBR).
Loading Capacity-62 MT each.
Unloading time of one wagon-20 sec.
Pressurized air opening & closing
system(Pneumatic operated).
In automatic wagon discharge system,
24 V DC supply are used for tripping
purpose.
WAGON
S

17. COAL-HANDLING SYSTEM:
Coal handling system is a system of transferring of coal
from coal-wagons to coal-bunker going through the
process of separation of material impurities, crushing of
coals, Coal sampling etc.
The first basic requirement to run the thermal power plant
is Coal.
Stage: Coal consumption (MT/day):
1 18000
2 16000
3 16000

18. Various equipments involved in coal handling are
Locomotives & Wagons
Track hopper
Paddle Feeders
Conveyors & its acces.
FG & Chutes
Crushers
Vibrating feeders
Belt Feeders
Stacker-cum-Reclaimer
SM, MD & MS
Trippers
Protective Switches
COAL HANDLING SYSTEM-
EQUIPMENTS

19. TRACK HOPPER & PADDLE FEEDER
At pit head power plants Merry Go Round system is
provided.
Wagon is unloaded along T/H
(66 hoppers in each T/H)
Track hopper capacity-3000MT.
 Below track hopper paddle feeder arrangement is provided to
unload coal to coal conveyors.
Rating: 1000/750 MTPH
Speed: 0-15 RPM/4.5 M/S

20. CONVEYORS & ITS ACCESSORIES
Conveyors transfers coal
from CHP to bunkers
• St-1: 21 Nos.
• St-2: 20 Nos.
• St-3: 23 Nos.
ACCESSORIES
• Conveyor belts
• Idlers & pulleys
• Drive Units
• Take ups
• Skirt board
• Scrapers etc.

21. 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=25 km.

22. IDLERS
Idlers consists essentially of rolls made out of seamless
steel 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.

23. POSITIVE ACTION TROUGHING TRAINERS –
automatically maintain troughing side alignment in
one-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.

24. 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)

25. DRIVE UNIT
Motors coupled to reduction gear with the help
of flexible coupling on the high speed shaft of the
Gear box
Flexible coupling on the input side
TAKE UPS
Take up pulley to facilitates –
Necessary tension for the drive to operate the belt
Sag at a point where required horse power will be
at a minimum and load will move with least
disturbance over idlers

26. SKIRT BOARD
Used with chutes at tail end of conveyors.
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.

27. Protection of conveyors:
 Pull Chord Switch
 Belt Sway Switch
 Zero Speed Switch
 Over flow Switch
 Metal Detector
 Magnetic Separator
 Suspended Magnet
 Motor Overload trip
 Path Permissive- O.K.
 Local EPB/SCADA EPB
 Breaker Feed Back
Fault
 Motor Electrical
Protection

28. Pull Chord Switches: A rope operated emergency protective
switch used to stop conveyor belt in case of emergency
 Operation: When the rope is pulled from any side the
switch gets operated
 Reset: Manually by changing the position of handle to off
position.
 Construction: Dust & weatherproof with high corrosion
resistance

29. Belt Sway Switches: Used to trip the conveyor in case of
over swaying of belt in either side.
 Operation: When belt edge strikes and pushes the roller
away the BSS actuates & trips the conveyor.
 Reset: Manual resetting required by lifting the roller
striker to the normal position.
 Construction: Switch housed in dust & weatherproof
enclosure having epoxy painted to withstand harsh
climate.

30. Zero Speed Switch: ZSS works on the principle of
comparison of pulses received from monitor with
standard pulses. It trips the drive motor when belt
speed is less than prescribed limit.
Sensor probe: it is to be installed with its sensing face
in close proximity of rotating object on which flags
are to be fixed. The sensor produces strong
electromagnetic waves which gets disturbed by
rotating flags resulting into generation of pulses.
Control unit: These pulses are fed to CU where they are
compared with standard pulses to sense the speed.
Location: In front of tail pulley or take-up pulley of
conveyors.

31. SEPARATING FOREIGN MATERIAL FROM CONVEYOR
MAGNETIC SEPARATOR
Any ferrous material on
the conveyor will be lifted
from the moving
conveyor.
 No Tripping involved.
MS is interlocked with
Conveyor start up.
When ferrous Metal is
picked up, the MS is
moved from the Conveyor,
de-magnetized and the
metal piece is removed.
METAL DETECTOR
Any Metal with an
area of 100 Sq Cm will
be detected.
Conveyor is tripped
after detection.
MD is also having
interlock with start up.
A sandbag is dropped
near the Metal piece
for easy search.

32. STACKER-CUM- RECLAIMER
•Coal to/from stock yard
•Capacity ---2000T/hr
Bucket wheel
Boom conveyor

33. RECLAIMER IN OPERATION
STACKER IN OPERATION
STACKER RECLAIMER
Bucket wheel
Boom conveyor Belt conveyor

34. PROTECTION & INTERLOCKS OF STACKER/RECLAIMER
 PCRD/CCRD Over tension
 Slew at 30 deg during stacking
 Slew end limit switch
 Bucket wheel anti collision
switch
 Traverse end limit switch
 Tripper chute indications
 Electrical protection of Motors
 Stacking/reclaiming indications
 PCS / BSS of B/C
 PCS & BSS of I/C
 Storm lock
 Rail clamp
 All EPB (6 Nos.)

35. Interlock & Protection of TRIPPERS
 PCRD over tension switch
 Tripper & Conveyor. EPB
 End limit switch
 Rail clamping
 Brake: (i) Manual (ii) Thruster
 Motor overload

36. Interlock & protection of PADDLE FEEDERS
 Over tension switch
 Traverse Trips
 Anti collision switch
 Auto Reverse
 End limit switch
 Auto Reverse
 Oil low level switch
 Main motor trips
 Oil temp. trip
 Main motor trips
 Rotor oil pressure switch
 Rotor trips
 EPB
 corresponding conveyor
 corresponding equipment

37. INTERLOCK CONDITIONS OF FGs OF ST-2
FLAP GATES
 FG - 3
 FG - 4
 FG - 5
 FG - 6
 FG - 13
 FG - 14
 FG - 15
 FG - 16
 FG - 17
 FG - 18
 FG - 19
 FG - 20
INTERLOCK CONDITIONS
 FG-5 Positioned on C-14A
 FG-6 Positioned on C-14B
 FG-3 Positioned on FG-5
 FG-4 Positioned on FG-6
 FG-15 Positioned on C-17A
 FG-16 Positioned on C-17B
 FG-13 Positioned on FG-15
 FG-14 Positioned on FG-16
 FG-19 Positioned on C-18A
 FG-20 Positioned on C-18B
 FG-17 Positioned on FG-19
 FG-18 Positioned on FG-20

38. CRUSHERS: To crush the coal from 200 mm to 20mm
size received from vibrating feeders.
Crusher hammers are made of
Manganese steel.
Hammer rows -4(st-1): 2*18+2*20
-4 (st-2): 4*23
Interlock & Protections:
 Belt feeder is
running(Interlock)
 Crusher motor over
current
 Crusher motor over load
 Belt feeder tripped
 Crusher Brg. Vib. very high
 Crusher Brg. Temp. very
high
 Scoup oil pr. Low
 Scoup water flow low/temp
high
 Motor electrical
protections

39. REASONS FOR COAL LOSS
 Coal handling loss.
 Coal Loss due to pilferage.
 Loss on account of spontaneous combustion, fire
& VM.
 Loss due to error in physical verification and
weighment error.
 Loss on account of excess moisture.
 Loss due to water washing & chute cleaning.
 Loss due to wind.

40. COAL COMBUSTION PROCESS
At Room Temp. Oxygen is absorbed – Its an
Exothermic reaction. Heat is given out.
At 155 deg. C, Volatile matter released
At 65 deg. C, surface moisture released
At 75 deg. C, Oxidation starts
At 190 - 250 deg. C, start of Thermal
decomposition.
At 250 - 300 deg. C, SELF SUSTAINED
COMBUSTION (FIRE)

41. TYPES OF FIRE
 Class A - Wood,
paper, cloth, trash
 Class B -
Flammable liquids,
oil, gas, grease
 Class C - Electrical,
energized electrical
equipment
 Class D -
Combustible metals

42. Different Kinds of Extinguishers
The 4 most common fire
extinguishers:
 Water type
 Dry Powder type
 Foam type
 Carbon Dioxide

43. fuel
heat
oxygen
FIRE Elimination methods
starvation
cooling
smothering