The whole world is suffering from energy crisis and the pollution is manifesting itself in the spiralling cost of energy. The economic, both micro and macro, growth of any nation depends on the power sector, because if that fails, slowly from minor to perhaps complete breakdown of the system can occur. Energy is created by the following plants: 1. Thermal 2. Nuclear 3. Hydel 4. Hydraulic 5. Gas 6. GeoThermal Alongwith cheap energy, control of the waste generation and pollution needs to be done, which is a bigger devil on the long run. A pioneer in such an enterprise is Mejia Thermal Power Station, Durlabhpur, Bankura. We undertook Vocational Training in this institution, and learned about the process of power generation and it’s by-products. The Power station has a total of 8 units, final two units inducted in 2012 and 2013, and thus being extremely advanced, with newest thermodynamic designs, and fast, digital and reliable controls. It employs Tilting Corner Fired Combustion Burner, and KWU West Germany Design Reaction Turbine, both manufactured by BHEL, India. MTPS units have many special features including Turbo mill, DIPC (Direct Ignition of Pulverised Coal) system, HPLP bypass system, Automatic Turbine run up system , and Furnace Safeguard Supervisory System.

1. - １ -
PROJECT REPORT
VOCATIONAL TRAINING IN DVC MTPS
PRESENTED BY
 UPAMANYU RAY
 KUNAL ADHIKARI
 KOUSHIK MANDAL
 SOUVIK SAHA
 PRAMEYA SAHA
 SAYANTAN BAGCHI
STUDENTS OF

2. - ２ -
SIGNATURE BY STUDENTS :
1)
2)
3)
4)
5)
6)

3. - ３ -
 CONTENTS
Preface 4
Acknowledgement 5
Introduction 6
Overview 7
Mechanical Operation 17
Electrical Operation 27
Chemical Operation 32
Safety 35
Control And Instrumentation Operation---------------------------------- 52
Conclusion 53
Bibliography 54

4. - ４ -
 PREFACE
The whole world is suffering from energy crisis and the pollution is
manifesting itself in the spiralling cost of energy.
The economic, both micro and macro, growth of any nation depends on
the power sector, because if that fails, slowly from minor to perhaps
complete breakdown of the system can occur.
Energy is created by the following plants: 1. Thermal 2. Nuclear 3.
Hydel 4. Hydraulic 5. Gas 6. GeoThermal
Alongwith cheap energy, control of the waste generation and pollution
needs to be done, which is a bigger devil on the long run.
A pioneer in such an enterprise is Mejia Thermal Power Station,
Durlabhpur, Bankura. We undertook Vocational Training in this
institution, and learned about the process of power generation and it’s
by-products.
The Power station has a total of 8 units, final two units inducted in
2012 and 2013, and thus being extremely advanced, with newest
thermodynamic designs, and fast, digital and reliable controls. It
employs Tilting Corner Fired Combustion Burner, and KWU West
Germany Design Reaction Turbine, both manufactured by BHEL,
India.
MTPS units have many special features including Turbo mill, DIPC
(Direct Ignition of Pulverised Coal) system, HPLP bypass system,
Automatic Turbine run up system , and Furnace Safeguard Supervisory
System.

5. - ５ -
 ACKNOWLEDGEMENT
This report has been prepared based on the Vocational Training in a
pioneer of Generation and Distribution of power, one of the most
technologically advanced, and the biggest Thermal Power Station,
capacity wise, in West Bengal and DVC, till date, Mejia Thermal
Power Station, MTPS Bankura.
With the report being as through as we could, we would like to express
our heartfelt and sincere gratitude to the authorities of MTPS and UIT
BU, for giving us the opportunity to undergo this learning.
We would also like to thank the highly experienced engineers, for the
concept building of the power plant, and teaching us the intricacies of
the working, monitoring and maintenance of the Thermal Power plant.
Some of them are:
1. Mr. Parimal Kumar Dubey, Retd.
2. Mr. S.K Pander, DCE
3. Mr. Arnab Mandal, EE
4. Mr. Prasun Kumar Mondal, EE
5. Mr. Pabitra Mohan Naik, EE
6. Mr. Ravi Roshan, EE

6. - ６ -
 INTRODUCTION
Power Plants are part of the infrastructure of the world and its essential
that these power plant facilities should be highly reliable and
economical.
”Damodar Valley Corporation” was established on on 7th July 1948.
Mejia Thermal Power Plant, MTPS is till date the largest thermal
power plant, capacity wise, among the DVCs, producing a massive
2340MW power.
Power generation are accomplished by a system that operates on a
thermodynamics cycle.
The devices or systems used to produce a net power output are often
called engines and the thermodynamics cycles they operate on are
called power cycle.
Installed Capacity:
1. Total Units - 8
2.Total Power Generation Capacity - 2340 MW (4X210 MW + 2X250
MW + 2X500 MW)
3.Source of Coal - BCCL and ECL, also imported from Indonesia,
Australia, etc.
4. Source of Water - Damodar River
5. Source of Fuel - IOCL, Servo, etc.
All equipments and machinery, micro to macro, is provided by BHEL.
Power generation is accomplished by a system that operates on a
thermodynamic cycle. In MTPS, modified Rankine Cycle is used.
The devices or systems used to produce a net power output are often
called engines and the thermodynamics cycles they operate on are
called power cycle.
Essentials of Steam Power Plant Equipment:
(a) A furnace to burn the fuel.
(b)Steam generator or boiler containing water. Heat generated in the
furnace is utilized to convert water into steam.
(c) Main power unit such as a turbo-generator to use the heat energy of

7. - ７ -
steam and perform work.
(d) Piping system to convey steam and water.
In addition to the above equipment the plant requires various
auxiliaries and accessories depending upon the availability of water,
fuel and the service for which the plant is intended.
Steam is generated in a boiler, expanded in the prime mover and
condensed in the condenser and fed into the boiler again, achieving
maximum efficiency.
The different types of systems and components used in steam power
plant are as follows:
(b) Prime mover (c) Condensers and(a) High pressure boiler
cooling towers
(d) Coal handling system (e) Ash and dust handling system
(f) Draught system (g) Feed water purification plant (h) Pumping
system
(i) Heating systems (SCAPH, Air preheater, economizer, superheater,
reheater, feed heaters)
 OVERVIEW
A Thermal power plant works on a basic principle of rotating a
generator, which then generates a voltage, according to Faraday’s Law
of Induction.
V  d / dt ,  being the flux cut
The Thermal part comes in when rotating the generator.
From burning fossil fuels (coal, oil, natural gas), it converts the energy
stored/heat generated, to heating water to steam (at very high
temperature and pressure created along the way), which is used to
produce shaft work in the Turbine, which is at a lower pressure. The
Turbine is coupled with the generator on a single shaft, with bearings.
The Steam utilised here is again cooled, converted to water, and heated
to the same temperature and pressure before passing it inside the
turbine. So, theoretically, the same water would be used again and
again (Practically, some portion of the water is lost along the way and
in the process).

8. - ８ -
The Entire Cycle of a running unit is pointed out in the diagram below.
Pressure, Intermediate Pressure, Low Pressure)
1. Main Steam Line 2. Reheated Steam Line 3. Turbine(High
4. Condenser 5.
Condensate Extraction Pump 6. Low pressure Heater
7. Deaerator 8. Boiler Feed Pump 9. High Pressure Heater
10. Economiser 11. SuperHeater(for 1) and ReHeater(for 2) 12.
Drum 13. Flue Gas Path 14. Air Flow 15. Air Heater (for PA and
SA) 16. Electrostatic Precipitator 17. Dry Ash Collection 18. Wet
Ash Collection 19. Induced Draught Fan 20. Chimney Stack
21. Synchro 22. 3Phase Generator

9. - ９ -
 Journey of Coal mine to Electricity
The entire journey, or the process of converting the stored energy to
heat energy, in turn to mechanical energy, to finally the electrical
energy can be described in the many steps.
Also, there are many by products of this process, among which ash is
used to make cement, and the steps are to be discussed.
1. Coal Path
Coal is the main source of energy in MTPS. Coal is mined locally, and
sometimes imported from Indonesia, Australia, etc. The coal is brought
in by the Indian Railway, which is then pulverised, and used primarily
for burning and converting water to steam, and later for making cement
from it’s ash. The entire path is:
(brings in
3000 tonnes
of coal)
Track Hopper
(drops the coal to
a belt
underground)
Crusher
House
(crushes the
coal to 20mm
size)
Transfer Point
(changes the
path direction of
coal from
underground to
bunker)
Stack
(stores coal
for later
use)
Bunker
(stores
the coal)
Feeder
(rotating belt
used to feed
coal to
pulveriser)
Coal Mill
(pulverise
s the
coal)
Furnac
e

10. - １０ -
Transfer Point
TP
Bunker
Feeder

11. - １１ -
(Crusher)
Fuel Path
Fuel or Oil is necessary for two
reasons: A. Boiler start up, B.
Cooling of equipments. Two
types of oil is used in MTPS,
Heavy Oil and Light Oil. While
start-up of the furnace, Light Oil is
atomised with high pressure Air,
and fed into a spark inside. As
Light Oil increases the temperature
primarily, due to it’s high cost, Heavy Oil mobilised and atomised with
high temperature and pressure Steam, is fed into the furnace to finally
facilitate increase of temperature and lightening it up.
(Top picture shows the oil storage tanks)
2. Air Path
Air is used for the operation of the boiler. It is used to carry Oxygen
and the Coal into the furnace, atomise LO, cool equipments, take out
the Flue Gas, and for the general respiration of the employees.

12. - １２ -
Primary Air Fan transports pulverised coal from mill to the furnace. It
also takes care that required temperature is attained for the coal to be
not too cold, not too hot.
FD Fan transports the air for combustion under Forced Draft
conditions (flow of air at pressure
above atm) to the furnace.
ID Fan is used to take out the
residual gases out of the furnace,
after combustion.
ID Fan is also intelligently
designed to heat up the PA and SA,
on their way to the furnace, to
facilitate flow and combustion. The
path of Flue Gas FG is turned by a
rotating cylinder at 2-3rpm, and the
heat exchange occurs as shown. PA
takes up 60° and SA 120° of the
semicircular flow path. Once FG
passes through through it’s side,
heat exchange occurs as it rotates
slowly, so at PA gets heated first, and then SA gets the remainder, and
FG leaves with it’s temperature dropped. Again, FG enters from the
Furnace, and the process goes on.
Atmosphe
re
Primar
y Air
Fan
Secondar
y
Air/Forced
Draught
Fan
Flue
Gas/Induc
ed
Draught
Fan
“Furnac
e”
Mill
Stac
k
2-3
rpm

13. - １３ -
(Stack)
3. Feed Water Cycle
The Feed Water is used mainly for generation of steam, and for
drinking.
Consider the steam used to rotate the turbine, is condensed, and again
converted to steam to rotate the turbine. Practically, due to uncountable
reasons perhaps, a portion of the steam and water is lost as vapour,
through all the following blocks. So, a make up water is needed to keep
the steam quantity and pressure continuous and same.
The condensate is removed of Oxygen from it through DeAerator
(preventing oxide formation in pipes). Booster pump and Boiler Feed
Pump increases it’s pressure one by one, and it is heated through a high
pressure heater, and an Economiser further, before putting it in the
Boiler Drum.
The water from the Barrage is treated (alum), gravity filtered using
three steps, gravel, coal and sand, and chlorinated for drinking
purposes in the Colony and plant. Further that, it is Aerated over a
cascade aerator, which facilitates easy separation of dissolved
undesirables. Then it is transferred to a DM, or DeMineralising plant
where all the minerals are extracted from it, using chemicals and resins.

14. - １４ -
This is done to ensure that no minerals deposit themselves on the
sides/bottom on evaporation. It is then transferred to the Drum.
The Boiler gets it’s water from the Drum itself.
Chlorination
Drum
Barrage/Mak
e up
Water
Reservo
ir
Pre-
treatme
nt Plant
Aerato
r
DM
Plan
t
Chlorinati
on
Drinkin
g
Water
Gravity
Filtratio
n
Dru
m
Condens
er
De-
aerator
Boost
er
PumpBoile
r
Feed
Pum
p
High
Pressu
re
Heater
Economis
er

15. - １５ -
4. Steam and Condensate Path
The Steam is the main entity for shaft work, that in turn rotates the
generator.
The Steam is of the DeMineralised water. Water from Drum is made to
fill the boiler walls, which converts to steam and is passed through
SuperHeater to facilitate flow, increase pressure, and make sure no
water is existent at all (which can damage turbine blades), and further
rotates HPT under high temperature and pressure. As the pressure
drops, ReHeater coil beside SH inside furnace increases the
temperature, feeds it into IPT and LPT again. As the pressure drops
below a critical, it cannot rotate any large scale turbine any more. So,
the steam is condensed, extracted via CEP and BFP, and heated along
the way (HPH, LPH, Economiser) to the Drum, to the Furnace again.
The cycle goes on.

16. - １６ -
Heating Coils (SH/RH)
5. Flue Gas Path
The Flue gas consists of ash-laden gas at a temperature around 325℃
out of the furnace. This gas has harmful particles, and needs to
discarded safely, or put to better use. In MTPS, the gas are released
through chimney, and ash is collected.
The Hot Ash from directly under the furnace is added with water, and
made into a Slurry.
The Gas path from above is passed through a ESP, which separates the
solid particles. VFD decides the rate of releasing gas into the Chimney.
The Dry Ash is collected, either manually or loaded and sent to SILO,
or it can also be made into a slurry if need comes.
Furnace Flue
Gas
ElectroStat
ic
Precipitat
or
VF
D
Stac
kDry
Ash
Manual
Collecti
on
SIL
O
Very
Hot
Ash
Wate
r
Wet
Ash
Slurr
y

17. - １７ -
ASH POND
4.
STEA
M
CYCL
E
2.
FUEL
PATH
3.
AIR
PAT
H
SILO
ALL THE PROCESSES OF THE THERMAL POWER PLANT
HAS BEEN BRIEFLY DESCRIBED IN THE ABOVE POINTS,
WITH PICTURES AND BLOCK DIAGRAMS. ALL THE
PROCESSES, IN A GIST:
1.
COA
L
PATH
6. FLUE
GAS
5.
CONDENSA
TE CYCLE
FURNA
CE

18. - １８ -
 MECHANICAL OPERATION
A Thermal Power plant is said to be comprised of 50-60% Mechanical,
20-25% Electrical, and 15-30% Control & Instrumentation
Engineering. All the designs of the functioning blocks, generators,
turbines, fans, boilers, pipes, are due to the application of Mechanical
Engineering.
In MTPS, it is no exception.
1.Coal Handling:
Coal delivery equipment is one of the major components of plant cost.
The various steps involved in coal handling are Coal delivery,
Unloading, Preparation, Transfer, Outdoor storage, Covered storage, In
plant handling, Weighing and measuring, Feeding the coal into
furnace.
MTPS uses the lowest grade of bituminous coal. Coal is moved around
either by conveyor belts, trains, or tractors.
As mentioned earlier in the Overview, coal comes in by rail. The trains
are BOBR (Bottom Open Bottom Release) type that operate an
opening by hydraulic action.
As the Coal is loaded, it is weighed automatically by Load cells, and
sent to crusher house via a conveyor belt. Then the 20mm crushed coal
is sent to the Bunker, whereforth it is to be fed into the boiler. Some
coal is sent to a Stack, for future use. It is desirable that sufficient
quantity of coal should be stored. Storage of coal gives protection
against the interruption of coal supplies when there is delay in
transportation of coal or due to strikes in coal mines. Also when the
prices are low, the coal can be purchased and stored for future use.
The transfer of the coal path, to the Bunker is done via conveyor bets,
inside Transfer Point. In MTPS, there are 8 TPs in series and parallel,
one for each unit. The coal basically falls from one belt to another, via
a feeder, and changes it’s direction.The bunker makes it fall into a
pulveriser. Pulverization relates to powdering. Pulverization of the coal
is done to increase the surface exposure to permit the rapid combustion,
which makes even the low grade coal burn easily.
For large scale generation of energy the efficient method of burning
coal is confined still to pulverized coal combustion. The pulverized
coal is obtained by grinding the raw coal in pulverizing mills. The

19. - １９ -
various pulverizing mills used are: 1. Ball mill 2. Hammer mill
3. Ball and race mill 4. Bowl mill.
The essential functions of pulverizing mills are as follows:
1.Drying of the coal Grinding 2. Separation of particles of the
desired size.
2. Proper drying of raw coal which may contain moisture (necessary
for effective grinding).
The coal pulverizing mills reduce coal to powder form by three actions
as follows:
(i) Impact (ii) Attrition (abrasion) (iii) Crushing.
In ball and race mill, a combination of crushing, impact and attrition is
used for pulverization of the coal between the grinding surfaces. Ball
and race mill is quite advantageous. It has: (i) Lower capital cost (ii)
Lower power consumption (iii) Lower space requirement (iv)
Lower weight.
However in this mill there is greater wear as compared to other
pulverizers.
What happens is a large tube is rotated at around 20rpm, which
contains high grade nichrome balls, which are extremely heavy. The
coal is fed into this, and when rotating, as the rpm is below the
threshold for UCM, the balls and the coal fall on each other with high
momentum. This crushes the hard coal under impact.
This type is used in units
1-6 in MTPS
For units 7,8, bowl mill is
used. Here, the coal is fed
from above to a slowly
rotating platform. There are
three huge rotating crushers
as shown inside, at 120°
each, that crush the coal.
Though it is a little costlier,
it has way less wear than
ball mill. The etches on the
crusher facilitate crushing
properly.
(Reject crusher)

20. - ２０ -
Once pulverized, the powder is pulled by a hot Primary Air, into the
furnace. 0.6kg/hour coal feed rate is necessary for making 1kWh of
power.
2.Boiler:
Thermodynamically boiling
is a process of heat addition
to water at constant pressure
and temp.
Boiler is an apparatus to
produce steam. Thermal
energy released by
combustion of fuel is
transferred to DM water,
which vaporizes and gets
converted into steam at the
desired temperature and
pressure.
The heat added is in two parts: sensible heat and latent heat. Prior
raises the temperature of and pressure of water as well as steam. Latter
converts water to steam (phase change).
Requirements of a good boiler:
A good boiler must possess the following qualities:
1.The boiler should be capable to generate steam at the required
pressure and quantity as quickly as possible with minimum fuel
consumption.
2.The initial cost, installation cost and the maintenance cost should be
as low as possible.
3. The boiler should be light in weight, and should occupy small floor
area.
4.The boiler must be able to meet the fluctuating demands without
pressure fluctuations.
5. All the parts of the boiler should be easily approachable for cleaning
and inspection.
6.The water and flue gas velocities should be high for high heat
transfer rates with minimum pressure drop through the system.
7. The boiler should conform to the safety regulations as laid down in
the Boiler Act.

21. Boiler can be classified into two types: In water tube boilers, water
circulates through the tubes and hot products of combustion flow over
these tubes. In fire tube boiler the hot products of combustion pass
through the tubes, which are filled with DM water. MTPS employs
water tube boilers.
Water tube boilers require less weight of metal for a given size, are less
liable to explosion, produce higher pressure, are accessible and can
response quickly to change in steam demand. Tubes and drums of
water-tube boilers are smaller than that of fire-tube boilers and due to
smaller size of drum higher pressure can be used easily.
Water tube boilers are classified as follows:
1. Horizontal straight tube boilers
2. Bent tube boilers:
3. Cyclone fired boilers:
Used in MTPS, various advantages of water tube boilers are as follows.
(i) High pressure of the order of 140 kg/cm2 can be obtained. (ii)
Heating surface is large, hence steam generation and coal combustion
is easier.
(iii) Large heating surface can be obtained by use of large number of
tubes.
3. BoilerAuxiliaries:
i.Boiler Drum: The Drum is the main storage of DM water, for
conversion to steam. The Drum consists of both water and steam,
separated. Drum water level should be optimum. More water, at such
high pressure, will purge water through the steam line damaging the
turbine. More steam means steam is in the pipe, and so at such high
pressure, there will be leakage and bursting of pipes. Water level is
maintained at ~ -50cm.
ii.Bottom Ring Header: The water from the drum enters the furnace
from this point. Also known as inlet header, it distributed to the thin
corrugated tubes, where it becomes steam initially, and fed to the upper
part of drum, and then SH.
iii. SuperHeater: The first stage of heating the steam upto its
maximum, abv. Saturation, such that maximum work is attained from
high energy (enthalpy) steam and after expansion in Turbine, the
dryness fraction does not reach below 80%. SH is actually a coil type
pipe, inside the boiler that allows rising temp and pressure to a very
high quantity (~540℃ ~170 kg/cm2).
- ２１ -

22. iv.ReHeater: In order to increase the cycle efficiency
thermodynamically, and reheat any vapour formed and feed it to IPT
LPT, High Pressure Turbine outlet steam is reheated in a coil similar to
SH, and then the high temperature steam is fed to TG again.
v.Economiser: After passing through LPT, the steam is condensed to
form water, as the pressure and temperature fall below a critical. Both
feed water and condensed water via BFP are heated on the way to the
drum. It utilises Flue Gas heat to preheat. Economiser recirculation line
connects down-comer with the economiser inlet header through an IV,
and a CV to protect and control economiser inlet.
Drains and Vents:
1. Boiler Bottom Ring Heater 2. Drum Drain and Vents 3. SH
and RH headers Drains and Vents 4. DSH header Drain and Vents
Drains facilitate draining of boiler, as required. Vents ensure removal
of air from boiler while startup, and facilitate depressurising.
vi.Primary Air Fan/Exhauster Fan: As the
name suggests, it is the primary air that enters the
furnace for combustion. As a result it is
responsible for carrying the pulverised coal along
with it. PA Fan is nothing but a huge cylindrical
Fan driven by a motor, beside the mill, that is
just able to suck in the fine particles inside the
mill.
Along the way, it is heated by the temperature of
Flue Gas, that decreases moisture content, and
facilitates flow and combustion. However, too
much heating might ignite the powdered coal,
and too less temperature will require lot more
time to ignite the coal, if so. To avoid this, the PA is channelled
through two pipes, as shown
Controlled properly, this ensures that the temperature of PA is standard,
optimum.
In MTPS, from Unit 1-6, Radial Type NDZV 20 Herakles PA FAN is
used. Orientation suction-Vertical/45° to Horizontal Delivery-Bottom
Horizontal.
vii.Secondary Air Fan/Forced Draft Fan: This Air is also fed to the
furnace, and it’s job is to maintain the oxygen content and temperature
of the boiler. It is an axial type fan(motor driven) and is used to take,
and heat up the atmospheric air, which then takes entry to boiler
- ２２ -

23. - ２３ -
through wind box. This Fan technically is Type Radial, NDZV
28/Sidor, and Orientation is 45° horizontal, same as PA Fan.
viii.Flue Gas Fan/Induced
Draft Fan: This is the air
that is actually inside the
furnace, consisting of all the
gases and particles that are
leftover after combustion. ID
Fan is responsible for
sucking out this air, flowing
it through a cylinder through
which both PA and SA
enters, and the economiser,
and then finally releasing the
gases into the air via chimney. Induced draft represents the system
where air/products of combustion are driven out by maintaining them
at a progressively increasing sub-atmospheric pressure. The ID fan and
Stack(high up touching the sky) performs the job for pressure drops.
The fan is forward curved centrifugal (radial) NDZV 31 Sidor, which
sucks the ash-laden gas at a temperature around 325℃ out of the
furnace to throw it into the stack.
(ID Fan motor is shown in the picture)

24. - ２４ -
4. Steam TurboGenerator:
With reference to the above diagram, Steam Turbines are prime
movers used to drive Turbo Generators for Power Generation. A
generator converts the mechanical shaft energy it receives from the
turbine into electrical energy. Combined, the duo can be called
TurboGenerator.
The choice of steam turbine depends on the following factors:
i. Capacity of plant ii. Plant load factor and capacity factor
iii. Thermal efficiency iv. Reliability
v. Location of plant with reference to availability of water for
condensate.
Steam turbine driven a.c. synchronous generators (alternators) are of
two pole designs in MTPS.
Generator losses appearing as heat must be constantly removed to
avoid damaging the windings. The Generators have cylindrical rotors
with minimum of heat dissipation surface and so they have forced
ventilation to remove the heat.
Alongwith that they generally use an enclosed system with hydrogen
coolant.
Units #1,2,3,4 210MW and #5,6 250MW Turbines
HP Turbine inlet steam is at 147kg/cm2 and 537℃. Steam enters HPT
through two combined main stop and control valves. Reheated, steam
is at 34.5 kg/cm2 and 525℃, fed into IPT and LPT. Both 210 MW and
250 MW turbines are a tandem compounded, three cylinders, single
reheat, condensing turbine provided entirely with reaction blading.
No. of stages: HPT-25 , IPT-double flow with 20 reacn stages/flow and
LPT-double flow with 8 stages/flow. Six steam extractors for
feed/condensate water heating have been taken from HPT exhaust and
11th stages of IPT for HPH, from IPT exhaust for deaerator and from
3rd, 5th and 7th stages of LPT forLPH.
Units #7,8 500MW Turbines
HP Turbine inlet steam is at 170kg/cm2 and 540℃.Steam enters HPT
through two combined main stop and control valves, and to IPT and
LPT through four combined reheat stop and control valves. Reheated
steam is at 40kg/cm2 and 530℃. 500 MW turbine is a tandem
compounded, three cylinders, single reheat, condensing turbine
provided entirely with reaction blading.

25. - ２５ -
The Generator used here are
synchronous motors in a squirrel
cage build, details of which will be
seen in the Electrical Operation
section.
(Generator Stator Winding
Diagram)
5.Ash Handling Plant:
Large quantities of Ash is produced in any steam power stations using
coal. Ash produced is about 10-20% of the total coal burnt in the
furnace. Handling the ash is a problem because its either too hot, or
extremely dusty and full of harmful gases.
Smooth handling of the clinkers, dust etc. is one of the function of the
ash handling equipment. The equipment should remove the ash from
the furnace load it to the conveying system to deliver the ash to a
dumping site or storage and finally it should have means to dispose of
the stored ash. The ash handling equipment should be corrosion and
wear resistant. In MTPS, ash is taken out in two ways, dry and wet.
The hot ash directly from below the furnace is treated with dry
handling, and the ash laden flue gas is treated either by dry or
wet(when dry systems are unavailable) method.
For Wet method, high pressure (H.P. ) pump is used to supply high
pressure water-jets which carry ash from the furnace bottom through
ash sluices (channels) constructed in basement floor to ash sump fitted
with screen. The screen divides the ash sump into compartments for
coarse and fine ash. The Dry method is to simply to collect only the
ash, after separation through ESP. ESP is discussed in the Chemical
Operation section.
Layout of the ash handling system:
The commonly used ash handling systems are as follows :
(i) Hydraulic system (ii) Pneumatic system (iii) Mechanical
system

26. - ２６ -
6.Chimney:
Chimneys at power plants are designed to release the gases above the
inversion layer. The exhaust from the power plants consist of
particulate matter, various oxides of nitrogen, sulphur and carbon at
very high temperature. At higher heights wind speed will be more and
disperses the pollutants properly. If chimneys are shorter in height
below the inversion layer, all the oxides may be trapped in atmosphere
resulting in health hazards to living organisms. Wind speed, Inversion
layer and landscapes play a significant role in designing the chimney.
A Chimney has two primary functions -
1.To carry undesirable combustion, also known as smoke, out of the
boiler.
2. To provide the draught that feeds air to the fire, keeping it burning.
The draft of the chimney comes from rising hot air.
In MTPS, there are 4 chimneys made of bricks, at 72m and 166m
heights.
6. Cooling Tower:
Cooling Tower, as the name suggests, is used for cooling the water.
Cooling towers are used to cool both the Feed Water and the
Condensed Water, to feed them back to their destination. There are two
types of cooling towers, natural and draft. Units 7 and 8 use Natural
Cooling Tower, that increases the surface area of the water to naturally
let the heat dissipate. Units 1-6 use 14 huge Fans that cool the water.
Draft CTs

27. - ２７ -
Natural CTs
 ELECTRICAL OPERATION
In any power generation and distribution place, Electrical Operation is
bound to be present. When power is sent from power station to all
other power station in the grid, it is known as distribution of power.
1. Generators:
Generators are the machines that finally generate the voltage, for which
all the employees and other processes are working tirelessly. Following
the principle of Faraday’s Law of Electromagnetic Induction, where
the voltage induced/developed depends upon the flux cut by a coil,
which depends upon the rotor, the generator used here is Squirrel Cage
Induction type generator.

28. - ２８ -
In MTPS, there are 8 generators, each for one unit. These are 3phase ,
2pole cylindrical rotor type synchronous turbo generators which are
directly coupled to the turbine via bearings, and a synchro.
A generator has mainly two parts, rotor and stator.
Stator
Stator is the fixed body of a
generator, that provides
constant magnetic field. The
body is designed to withstand
internal pressure of
hydrogen-air mixture without
residual deformation.
The stator winding has 3phase
double layer short corded bar
type lap winding having 2
parallel paths. The winding
bars are insulated. The
following insulation
techniques are to used for
reliable insulation:
a. Highly heat resistant epoxy resin b. Highly pregnable mica paper
tape c. Thermal relaxation stress layer providing high heat cycle
resistance.
Rotor
Rotor is, as read, the rotating part. It is responsible for the flux cutting.
It is a cylindrical type shaft, coupled with the turbine shaft. It is forged
in one piece from Chromium Nickel Mb and Vanadium steel.

29. Generator is filled up with H2 gas, for cooling purpose, purity
maintained >90%.
Specifications:
Rated kW capacity: 210MW
Rated terminal voltage: 15750V
Rated stator current: 9050 A
Rated frequency: 50 Hz
Rated kVA capacity: 247000 kVA
Rated Pf: 0.85 lag
Rated RPM: 3000
Efficiency: 98.55%
Critical speed of rotor: 1370/3400 RPM
Max Temp. of cooling water: 37℃
Max Temp. of cooling hydrogen: 44℃
Max Temp. of cooling distillate: 45℃
Max Temp. of stator core: 105℃
Max Temp. of stator winding: 75℃
Max Temp. of rotor winding: 115℃
2. Transformers
Transformers are employed after generation of electricity, for
transmission at long distances. In MTPS different types of power
transformers are employed:
Types of Transformers:
i. Generator Transformer:
This is the main power transformer employed in the power plant. It
steps the voltage from 21kV to 220kV and delivers the power.
Stepping up the voltage reduces the transmission losses which occur
during the power transmission to long distances.
ii.Unit Auxiliary
Transformers:
These transformers are
connected to the
Generator Transformer
bus. These
transformers steps
down the voltage from
220kV to 6.6kV
(220/6.6kV) and
- ２９ -

30. supply the power to the electrical auxiliaries present in the plant
(motors, pumps, drives, lighting and other plant loads).
iii. Station Transformer or Startup Transformer:
This transformer provides electrical power to the plant during startup
when no supply is available to the plant (generator is not operating). It
also steps down the voltage like unit auxiliary transformers and supply
power the plant auxiliaries.
Station Transformer and Unit Auxiliary Transformers are connected to
the grid.
iv.Auxiliary Transformers:
These are small distribution transformers supply power to plant
electrical auxiliaries rated at 220V by stepping down the voltage
(6.6kV/220V).
3. Switchyard
This is the long yard through which the transmission lines bid adieu to
the plant. Switchyard is essentially a hub for electrical power sources.
In MTPS, there is a big switchyard for units 1-6, and another switch
yard for units 7&8. Switchyard can be centrally controlled in a room.
Important points which dictate the choice of bus switching schemes are:
i. Operational Flexibility
iii. System security.
v. Protection scheme
ii. Ease of maintenance
iv. Ease of sectionalizing
vi. Installation cost and land
vii. Ease of extension in future.
The basic components of a switchyard are as follows:
1.Circuit Breaker-Used to break the circuit under no load, full load or
short circuit conditions. SF6 CBs are used.
2. Isolator-Used to isolate a particular circuitry from the rest, to allow
works during off load operations.
3.CT-Current Transformer, used to serve the purpose of metering
current and power, and protection.
4.PT-Potential Transformer, the same type of transformer as CT just
connected in parallel. Used to meter voltage and power, detect
abnormalities and isolate instruments from the HV side.
5. Power Transformer-Used to change the voltage level. At the sending,
and usually stepup end, 33/11kV transformers are used for
transmission. At the receiving end, usually sub stations it is stepped
down.
- ３０ -

31. - ３１ -
6. Insulator-The connections need to insulated from the surroundings
to prevent accidents. Steel/cement structures are used to mount up the
live equipments. Porcelain insulators are used for small scale insulation
at transmission wire level.
4. Switchgear
In an electric power system, switchgear is the combination of electrical
disconnect switches, fuses or circuit breakers used to control, protect
and isolate electrical equipment. Switchgear is used both to de-energize
equipment to allow work to be done and to clear faults downstream.
This type of equipment is directly linked to the reliability of the
electricity supply.
Typically, switchgear in substations are located on both the high- and
low-voltage sides of large power transformers. The switchgear on the
low-voltage side of the transformers is located inside building, with
medium-voltage circuit breakers for distribution circuits, along with
metering, control, and protection.
MTPS uses SF6 switchgear.
Type of Relays used in MTPS for protection of Power System
components
1. Auxiliary relay for isolations
3. Directional over current relay
5. Multi relay for generator function
7. Instantaneous relay
9. Lock out relay
11. Numerical LBB protection relay
2. Fail accept relay
4 Master trip relay
6. Supervision relay
8. Bus bar trip relay
10. Contact multi relay
12. Trip circuit R-phase

32. relay
13. Transformer differential protection relay
14. EUS Section relay 15. DC fail accept relay
16. Trip circuit R-phase super relay Y-phase B-phase
 CHEMICAL OPERATION
The work of chemicals is essential when we’re talking about water
treatment, demineralisation of the raw water, and electrostatic
precipitation.
1.Water Treatment
Water Treatment is done for mainly three purposes: Drinking,
Equipment cooling, and Steam generation. For all these processes
water must be treated, such
that there is no impurity (for
drinking) and no minerals
(such that no oxides, sulphides,
etc make themselves at home
inside pipes and equipments)
As discussed before, Water
treatment consists of many
parts:
i.Aeration: In this process,
raw water is sprayed over
cascade aerator in which water flows downwards over many step in the
form of thin waterfalls. Cascading allows separation of dissolved
gases., or to help in oxygenation of mainly
ferrous ions in presence of atm. oxygen to
ferric ions .
ii. Coagulation: This takes place in
clariflocculator. Coagulants destabilizes
suspended solids and agglomerates them into
a heavier floc, which is separated.
iii. Gravity Filtration: Filters remove course
suspended matter and remaining sludge/floc
after 2., and also reduces chlorine demand of
water. Filter beds are developed by placing
gravel or coarse anthracite and sand in layers.
They are cleaned by backwashing or air
blowing through it.
- ３２ -

33. 3.Electro Static Precipitator (ESP)
The work of ESP is to ionize particles as RH and ROH, to facilitate
their separation.
The principal components of an ESP are 2 sets of electrodes insulated
from each other. First set of rows are electrically grounded vertical
plates called collecting electrodes while the second set consists of
wires called discharge electrodes.
The below figure shows the operation of an ESP.
The negatively charged fly ash particles from the furnace, via ID fan,
are driven towards the collecting plate, as discussed before. The
positively charged ions then travel to the negatively charged wire
- ３３ -
iv. Chlorination: Neutral organic matter is very heterogeneous i.e
consists of many classes of high molecular weight organics.
Chlorination is done at .05ppm, so as to remove the germs and
organics, make it good for drinking, but not too much as that would
backfire.
(Chlorine plant pumping in the above picture)
2.DM Plant
In De-Mineralised Plant, the filter water of Water Treatment Plant is
passed through the pressure sand filter (PSF) to reduce turbidity and
then through activated charcoal filter (ACF) to adsorb the residual
chlorine and iron in filter water.

34. - ３４ -
electrodes. Collected particulate matter is removed from the collecting
plates by a mechanical hamper system, or if blockage occurs more,
then manually.

35. - ３５ -
 SAFETY
“Safety First, and Safety Must” is the safety motto of MTPS. Safety
while working is a must thing to consider, as at first human lives, and
then high grade and costly equipments are at risk.
For example, there are 6types of fire extinguishers, A,AB,B,BC,C,AC.
Fire type A refers to clothes catching fire, B means fire due to oil, and
C due to electrical short circuiting. AB, BC and AC extinguishers are
capable of removing two types of fire simultaneously.
The engineers and trainees must have safety helmet and boots on,
while at site. All workers have a must Personal Protective
Equipment(PPE). PPE consists of fluorescent shirts, head ear and nose
protection, gas mask, safety boots, ropes, gloves, etc. Not only
wearables, there are monitoring and sensing systems that give an alarm
when in danger.

36. - ３６ -
 CONTROL AND INSTRUMENTATION
OPERATION
The use of Control, Instrumentation and Automation is spreading like
wildfire. All industries, plants, institutions employ it for monitoring,
controlling, and running every part of a system, and further use it on
more complex conditions and circuits. MTPS being a technologically
advanced power plant doesn't lag behind.
Before the advent of control engineering per se, control, sequencing,
and safety interlock logic for any desired place was mainly composed
of relays, cam timers, drum sequencers, and dedicated closed loop
controllers. Since these number to thousands in even a medium sized
plant, the process for updating and starting up after tripping was very
time consuming and costly, as each part was to be wired and rewired
individually.
Instrumentation is defined as the art of measurement and control (both
automatic and manual) of process variables within a production,
manufacturing, distribution or surveillance area.
The process variables used here are the various parameters that define
the optimum running conditions of the plant, every one of them; like
pressure, temperature, level, flow, pH, humidity, speed, etc.
Control engineering or systems is the engineering study that applies
control theory to design systems that act according to the process
variables, as desired. Automation reduces more gross errors than jobs,
and is thus finding interest worldwide.
We being from AEIE
discipline, lay more
stress in the
measurement, calibration
and control of the entire
power plant.
C&I(Control &
Instrumentation)
engineers are responsible
for reseearch, design and
development of measurement and control devices/systems.

37. - ３７ -
Control Systems
PLC
A hardware system can be controlled
via desired logics, with the help of
Programmable Logic Controllers, or
PLCs. A PLC is an industrial computer
which has a rugged design and both
hardwired and software(program)
controls. It is actually a large hardwired
logic, that has an electronic CPU.
These can range from small ‘building
brick’ devices with tens of inputs and
outputs, in a housing integral with the
processor, to large rack-mounted
modular devices with a count of
thousands of I/O, interconnected with
other PLC/SCADA, perfect for a thermal power plant where control of
one part depends on the variables of many other parts.
PLC works in digital logic. A scanner keeps looking for inputs to the
PLC, and if logic is high, then the input is transmitted to the field.
DCS
DCS stands for
Distributed Control
System. It is them most
advanced kind of
system that allows the
user to take care of
multiple inputs at one
time. Autonomous
controllers are
distributed throughout
the concerned system, but central operator is present. In units 7&8,
DCS manages the entire power generation process, which will be
discussed later. DCS is initially more costly, but faster, more reliable
and easier to use.
All the inputs are entered via a computer, and thus there are adapters
and a networking system that allows the distribution and

38. - ３８ -
interconnection of several inputs to the individual cards. Cards mean
electronic cards that process room inputs and maybe send it to field as
a desired output. A scanner keeps looking for inputs to the DCS, and if
logic is high, the input is transferred to its unique IP address for
processing. Cards represent actual measurements and processes, like
RTD, Thermocouple, Analog I/O, Digital I/O, etc cards.
All the cards needed for a particular process, like for Mill to Furnace
process control, together for a DPU, Distributed Processing Unit.
There are always 2DPUs at work for a process, and one DPU kept on
hot standby mode.
Overview of the Plant Control System
The plant is divided into three functions:
1.SG (Steam Generator) - All the processes of generating steam.
Boiler, coal mills, oil guns, etc.
2. TG (Turbine Generator) - All the processes of turbine and generator
rotation. Turbine, generator, vacuum P/O, etc.
3.BOP (Balance Of Plant) - All the processes responsible for efficient
and smooth running of plant. PA, FD, ID fans, HP, LP heaters, etc.
All the field outputs are verified, or fed back to the controller via
feedbacks.
(Spark Ignition Feedback
Switch)
Comput
er
Control
Networ
k
HMI
Fiel
d

39. SG
In Boiler, the drum level,
superheater temperature, PA,
fuel and SA are controlled.
Drum level is controlled
corresponding to a measured
level, which is never allowed
to deviate much. The drum
level is maintained at around
-50cm below the divider.
Drum pressure is maintained
at ~170kg/cm2. The main
steam temp, pressure and flow
are maintained at ~540℃
165kg/cm2 and 1400TPH.For
the air, SADC, or Secondary
Air Damper control
is present, which are
parallel vents which
open or close to a
degree
set.Superheater
temperature is
maintained at a level
by using a
de-superheater,
following SH, such
that the steam does
- ３９ -
However, there are emergency
control panels for most blocks of a
process, just beside the physical
design of those blocks.

40. - ４０ -
not become too hot.
Also for boiler startup, there is a controlled spark generator (picture),
which lights up the oil and then the coal.
As for the coal feed rate, ~45TPH coal is fed to the mill by the feeder,
for each functioning mill.
The feed water flow is controlled at ~1300TPH.
Control systems also can completely isolate or stop a certain input.
ESV, emergency stop valves are employed to such effect.
However, there is also a special case-tripping of the process. Lets say
that the boiler working must be tripped, or it should be stopped with
immediate effect, because lets say, the PA fan has stopped rotating,
Drum level has become abnormal, Superheater pipe is leaking, HPT is
at maintenance work, etc. For many conditions of every process out
there, the process itself must be stopped immediately to avoid further
damage. That condition is also controlled by this branch of engineering,
by putting all those conditions, negative high or low (trip yes or no) to
interconnected logics (AND gates, primarily). So, as one condition is
satisfied, the unit trips.
There are similar conditions and logics for the startup of the process.
TG
In TG portion, there are similar type trip conditions and normal
controls.
There are many control and stop valves in the steam inlet and outlet
pipes of the turbine, in case steam pressure, temperature and flow
become below or off the charts. There are also cases of extreme
vibration, sparks inside generator and overheating, that can result in the
control system becoming useful.
(IPT valve)

41. BOP
Ironically,
BOP covers
more content
than the SG
and TG.
There are
numerous
controls
spread all
over the
plant, for the
auxiliaries
and more.
For ID fan, there is a VFD, or Variable Frequency Drive present on site,
that sets the speed of rotation of the drive motor according to a
frequency set by the control. This in turn controls the amount of flue
gas extracted and released into the atmosphere. There are similar
controls for the other Air systems. PA temperature is controlled by
controlling the amount of air sent for heating, and the rest is direct
atmospheric air.
The Feed water rate, and the water entering the drum is also controlled
via vent like valves.
A fall in pressure operates the master relay which in turn operates the
servomotor coupled to the vanes of the induced draught (ID) fan to
open them slightly and simultaneously the secondary air fan damper
gets opened proportionately. This is the automatic boiler operation
control, which helps in better combustion.
The Chemical operations are controlled, like amount of chemicals
applied, at a particular temperature and pressure, are crucial for the
efficient and speculated operation of the processes.
The Electrical Controls, though employs Control Systems, is not
usually controlled in the Central Control Room by C&I engineers, as
the electrical systems are not their area of expertise. The Electrical
Controls consist of all the parts previously discussed in ‘Electrical
Operation’. It also shows the electricity distribution inside the plant
itself.
- ４１ -

42. - ４２ -
Individual Handling Plant Controls
CHP
Coal Handling Plant is the area where the Coal comes into the plant, and is
sent to the bunker. The entire process is controlled via Rockwell Automation.
The Conveyor Belt speed, TP feed rate, Crusher House functions, and
Stack Loading are controlled via on site control system with feedback
systems. The transfers take place via a Flap Gate, that opens the path
for only one direction at a time.
T
H
Convey
or 1A,
1B
TP 1 FG 1,
2
RH
1 FG 3,
4
Convey
or 4
TP
5
CR
Hous
e
FG 6 TP 3
Stack
Bunk
er

43. - ４３ -
CHP Control PC
AHP
Ash Handling Plant is the area where the Dry and Wet ash from flue
gas and below the furnace respectively are handled. AHP, like CHP,
utilises PLCs for control. Siemens Automation is used in AHP.
AHP controls various parameters of the said process, such as amount
of Ash collected, temperature and pressure of the Ash, adjustment of
opening, and closing valves of the hoppers, pumps for the sump water,
treatment of the water, pumping away the slurry, etc.
(Low Pressure Water Pump of
AHP)
Water Treatment Plants
The water treatment, as discussed at the beginning, include many steps.
As we know that C&I is responsible for monitoring and controlling
every other process in the plant, this is no exception.

44. The Feed water rate, CEP, CWP,
Chlorination, etc is controlled locally
and centrally.
(Left: Local Control Panel for
Chlorination plant
Bottom: Local measurement and
control for chlorine content and
parameters)
Sensors Used in the plant
Pressure Transducers
Pressure and pressure drop is measured in various places, all over the
plant.
Mainly secondary transducer Bourdon Tube is used for pressure
reading.
Components of Bourdon Tube:
1. C/U shaped tube
5. Hair Spring
2. Link
6. Pointer
3. Pinion 4. Gear Set
7. Scale
Bourdon tubes work in the principle of height change in a U tube when
pressure is changed. When pressure is changed on the measuring end
of the U, the height changes on the open end. A piston (frictionless) is
attached to the open end, above the fluid, which is free to move up and
down as the height changes. Spring, gear set, and pointer is attached to
the piston, and so, as it moves up and down, the pointer is configured
to move to and fro left to right, corresponding to the ups and downs.
Bourdon tubes are made of copper alloys or stainless steel, and is quite
- ４４ -

45. - ４５ -
sturdy and accurate at the same time, which makes it a famous choice.
However, if the fluid pressure to be measured is of high viscosity, then
Bourdon tube principle cannot provide proper output. So, for that
Diaphragm Pressure Gauges are employed, that involve the
capacitance change of a plate with respect to distance between a fixed
plate, and the diaphragm. As the pressure increases, the diaphragm will
be pressurised to move closer to the fixed plate, increasing the
capacitance. Proper calibrated meter will hence read the pressure at
that point.
For vacuum pressure reading, Pirani Guages are used. They are
resistive transducers that provide a voltage proportional to the
resistance change, corresponding to the pressure change.
Pressure switches are also
used in the measurement
and control. A pressure
switch is a form of switch
that closes electrical
contact when a certain fluid
pressure has been reached.
The switch maybe designed
to make contact either on
pressure rise, or fall.
Pressure switches can be
used for alarm systems that
inform an operator about a small critical change, which maybe
overlooked.
Temperature Sensors
Temperature and pressure measurement are the most vital
measurements of any thermal power plant. There are numerous ways to
measure temperature accurately.
RTD
Resistance
Temperature
Detector, this is a
resistive
transducer
(primary) that provides a voltage output corresponding to resistance

46. - ４６ -
change, which is proportional to the temperature.
[ RT=R0(1+α1T+α2T2+…) ]
The meter can be calibrated accordingly, with the varying voltages.
The RTD material is of high resistivity, temperature stability and high
coefficient.
RTD used in industries and
plants are either three wire or
four wire configuration. The
latter is the most accurate.
A 3wire configuration is
drawn beside. This is to make
the effect of lead wire
resistance as minimal as possible. Lead wire resistance is not negligible
in a thermal power plant that is both hot in general, and the distance of
control room far from the actual measuring point. But close scrutiny of
the diagram shows that Vo is still dependent upon one lead wire. Hence,
3wire configuration, is not the most accurate.
A 4wire configuration is
drawn beside. This
configuration is free of the
effect of lead wire resistance
on the numerator of the
theoretical equation.
The diagram shows that lead
wire is not present, and thus it is highly accurate, trade off, the price.
RTDs are mostly made of platinum
and nickel.
PT100 and PT1000 are commonly
used RTDs, as platinum has higher
resistivity. PT100 and 1000 means
that the resistance of the RTD at
0 ℃ is 100Ω and 1000Ω
respectively. The leads require
insulated leads attached. The measuring point, and usually most of the
leads require a housing or protective sleeve, often made of a metal
alloy that is chemically inert and mechanically strong.
Since RTD is a resistive gauge, it has limitations to its range, and
hence cannot be used for very high temperature measurement. But, due

47. - ４７ -
to it’s high accuracy, ruggedness and low cost and maintenance, RTD
is used in places where temp<200℃
Thermocouple
Thermocouple is a
bimetallic strip that,
under Seebeck effect,
provides a voltage when
a temperature difference is provided between two ends. Under OC
circuit conditions where there is no internal current flow, the gradient
of voltage is directly proportional to the gradient in temperature.
Thermocouples, since metals, have huge range though average
accuracy and linearity. The problems of accuracy and linearity can be
minimised by using cold junction compensation and balancing
thermocouples. K and R type thermocouples are used to this effect.
Flow Sensors
Flow measurement is the quantification of bulk fluid movement. Flow
can be measured in a variety of ways. Positive displacement flow
meter accumulate a fixed vol. of fluid and then count the number of
times the volume is filled to measure flow. Flow is measured mainly
using dp meters. dp, or differential pressure between
Orifice Meter
An orifice plate is a device
used for measuring flow
rate, for reducing pressure
or for restricting flow. It
uses Bernoulli’s principle to measure the flow with the help of height,
and the pressure difference. An orifice plate is a thin plate with a hole
TYPE METALS
TEMP
RANGE
(℃)
SENSITIVITY
(μV/℃)
K
CROMEL
ALUMEL
-200 to
1200
40
R
PLATINUM
PLATINUM-RHOD
IUM
0 to 1400 7

48. - ４８ -
in it, which usually is placed in a pipe. When a fluid passes through,
it’s pressure builds up slightly upstream of the orifice but as the fluid is
forced to converge to pass the hole, the velocity increases and the fluid
pressure decreases. A little downstream of the orifice the flow reaches
its point of max convergence where the velocity reaches the max.
Beyond that the flow expands the velocity falls and the pressure
increases. By measuring the difference in fluid pressure across
tappings upstream and downstream of the plate, the flow rate can be
obtained from bernoulli’s eqn.
Venturimeter
Venturimeter uses
the same principle
as that of orifice
meter. There is a
constriction in the
pipe flow, that
creates the pressure
difference, that is proportional to the flow and
hence the properly calibrated meter will read the
flow. The construction of the venturi are:
1.Short converging part: It is a tapered portion
whose radius decreases as we move forward.
2.Throat: It is middle portion of the venturi. Here
the velocity of the fluid increases and pressure
decreases. It possesses the least CSA.
3.Diverging part: The part from where the fluid
diverges.
DP meters
Differential
Pressure
meters is defined as the
difference between two
pressures. DP transmitters use a
reference point called the low
side pressure and compare it to
the high side pressure. Ports in
the instrument are marked high side and low side. The DP reading can
be either negative or positive depending on whether the low side or

49. - ４９ -
high side is the larger value. A DP transmitter can be used as a gauge
pressure transmitter if the low side is left open to the atmosphere.
Level Measuring Devices:
The level measuring devices can either be analog or digital values.
Ultrasonic sensors are used for the most parts. Sometimes, capacitive
level measurement techniques are used for small
scale measurements.
Liquid levels are measured
using Float/Displacer type
sensors. They use LVDTs
and RVDTs for very
accurate measurements.
Radar type level
measurements are seen in
Hotwell.
Drum levels are
measured with the help of EWLI, or
Electronic Water Level Indicator. It
uses probes at regular intervals on the
walls, and when the level touches the
probes at the certain level, it becomes
high, ascertaining that the water is at
present at that level. So, till the level
that probe is high, water is present
there. In drum, it is used to measure
the level of water and steam, moderately accurately.
indicator in the picture)
(Drum level

50. Others
Aerofoil: Used to measure the flow of SA. It is a 3D structure, with an
inbuilt dp structure, that ultimately measures the flow.
Flame Scanner: Actually a photodiode configuration, it measures the
intensity of the flame inside the furnace. Light falls on a focus F
accordingly to the light inside the furnace. So, light sensor measures
voltage according to the intensity of light. The intensity inside is
proportional to the pressure inside, too. Flame scanner is needed to
know the exact temperature, and type of flame inside. Too hot might
be dangerous for the boiler.
The furnace pressure thus calculated from this sensor, is maintained at
~ -5 kg/cm2, so as to be of extreme low pressure (imagine vacuum)
from the outside. The boiler body is designed to withstand the outside
pressure. If the pressure was not maintained at a negative, then flames
would be coming outside, that can result in mild damage to
irrecoverable catastrophe.
Tachometer: This measures the rpm
of a rotating body. So, the rpm of any
motor is perfectly read by this device.
Proximity: The proximity sensors
are also used to read no. of cycles,
and hence, the speed, volumetric
TPH carried by the rubber belts. The
proximity sensors have a rotating
body that rotates with the rotation of
the motor that drives the belt.
Calibration
The words "calibrate" and "calibration" is thought to be derived from a
measurement of the calibre of a gun. Calibration, by definition is the
operation that, under specified conditions, in a first step, establishes a
relation between the quantity values with measurement uncertainties
- ５０ -

51. provided by measurement standards and corresponding indications
with associated measurement uncertainties (of the calibrated
instrument or secondary standard) and, in a second step, uses this
information to establish a relation for obtaining a measurement result
from an indication.
This definition states that the calibration process is basically a
comparison of the tested equipment or measurement with a standard
one, but it also introduces the concept of measurement uncertainty in
relating the accuracies of the device under test and the standard.
Calibration may be required for the following reasons:


 a new instrument
 after an instrument has been repaired or modified
 when a specified time period has elapsed
 when a specified usage (operating hours) has elapsed
 before and/or after a critical measurement
 after an event, for example after an instrument has been exposed
to a shock, vibration, or physical damage, which might potentially
have compromised the integrity of its calibration
sudden changes in weather
whenever observations appear questionable or instrument
indications do not match the output of surrogate instruments
Hence it is clear that calibration is a necessary and frequent process
that should be done for correct measurement, which in turn means that
the process variables of the control system
will be correct. Calibration is performed by
C&I engineers.
This is a calibration entity. Calibration, as
defined is the comparison, and hence
adjustment of a tested process with a
standard measuring device.
Taking the example of a feeder belt, for
calibration, the belt is emptied. The weight,
the speed, and all the other parameters
related to it is measured from the reading it
gives. The reading is noted.
It will be erroneous of course, so, a test
weight or a test process is initiated, which
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52. - ５２ -
then gives another reading. Comparing the same process with another
standard measurement process, the current parameter measuring meter
is adjusted.
Also, the zero speed or dead weight parameter values can be subtracted
from the test weight parameter values, but the latter process is more
accurate, though more time consuming.
Pollution Control
Pollution control is yet another thing to keep an eye on. With pollution
levels rising, the world will be in a serious problem in the years to
come.
There are government set rules, regulations and values that is of
interest to both mechanical engineering designers and the
instrumentation engineers at MTPS.
The main pollutants are either removed chemically in water treatment
plant, or, the maximum is released through the chimney. There are
oxides of carbon, nitrogen, sulphur, and more in the gases, which are to
be maintained.
Stack outlet levels are maintained at:
Opacity at 72m: 13.17mg/Nm3 Opacity at 166m: 16.1 mg/Nm3
SOX: 145.8 ppm NOX: 170 ppm H2O: 7 ppm CO: 10 ppm
CO2: 85 ppm
These levels are maintained via scrubbers, flow rate controllers, VFDs
(variable frequency drives, that control ID fan speed, hence control the
amount of pumping of flue gas), etc. All the parts have set points, and
to-be-maintained levels, which are done so by the help of sensors that
read the amount of each pollutant, and control systems, that control the
level by which outlet valves are opened or closed.

53. - ５３ -
 CONCLUSION
In conclusion, we would like to thank again the authorities at this
institution and our university. The practical experience we have gathered
in this massive plant generating 2340MW of power, has not only
increased our interest for the subject, but will definitely be a stepping
stone in building a bright professional career in future life. It gave us the
spectrum to utilise our theoretical knowledge and to understand it in
practice.
The troubleshooting operations in the plant, in practice, and the
environment and the decision making in case of crisis has instilled in us
all, a desire to work harder and be more confident to work in an industrial
atmosphere.
Also, this training was not just about book learning. We learnt a lot about
professionalism, and forming interpersonal relationships with
professional executives, staffs and workers, and to develop the hardcore
leadership ability to work
and lead a group towards a
common benefit.
We would like to suggest a
few points of counter
measures to any mishap or
drop in efficiency that may
occur. The counter measures
for plant longevity are not
simply a return to the
counter measures against
plant deterioration.
Further improvements with
electronic control is to be
done, like shorter start up
time, automation of every
point, and proper monitoring
systems with alarms, and
finally, digitization of the
systems from analog.

54. - ５４ -
 BIBLIOGRAPHY
 MTPS Technical Data and Guides
 Google
 Wikipedia
 https://www.fujielectric.com/company/tech/pdf/r51-3/r51-3.pdf
 http://www.dictionary.com
 SlideShare
 Measurement by E.O Doeblin
 Power Plant Engineering books
 Control System books