CESC SGS project report

UNIT 1
INTRODUCTION
Kolkata has come a long way on the wings of power. Through rapid growth and change
during the world’s most eventful decades. CESC, a power utility in India was set up in
1899. It was first Thermal Power Generation Co. in India. In 1989 CESC became a part of
RPG group which has a strong presence in the fields of power generation, and supplies
power to the city Kolkata, serving 2.4 million populations across its area of 567 sq. km. It
has an initial licensed area of 14.44 sq. km. CESC brought electricity to Kolkata 10 years
after it came in London. The peak load so far handled more than 1300 MW and it’s no of
employees are 10460 (2009-10) From its first DC station at Emambaugh Lane operating
from April of 1899 units of CESC now became an ISO 9001: 2000 & 14001:2004 Co. &
established its latest station at Budge Budge (1997) with a capacity of 500 MW which is
one of the largest ever private industrial investments in West Bengal.
Today CESC has three flagship generating stations in West Bengal now.
Generating
Station
Year of
starting
Installed
capacity
Feature of
boiler
Titagarh (TGS) 1983 240MW (60MW x 4
units)
Pulverized fuel
Southern (SGS) 1991 135MW (67.5MW x
2 units)
Pulverized fuel
Budge Budge (BBGS) 1997 750MW (250MW x
3 units)
Pulverized fuel
Table: CESC Generating Stations

SOUTHERN GENERATING STATION
SGS is one of the newer generating stations & is a pulverized fuel thermal power station of
CESC, situated on Garden Reach Road, Kolkata. In 1991 this station was started. This
generating station has 2 units each of 67.5 MW power generating capacity.
Figure: Schematic diagram of “SGS” Unit

GENERAL INFORMATION
Address 28,Garden reach road, kolkata-700024
Capacity 135 MW (2 x 67.5MW)
Total area of the campus 41.45 acres
Boiler first lit up on
Unit#1: 16.03.90
Unit#2: 13.02.91
Commercial generation started on
Unit#1:25.09.1990
Unit#2: 10.06.1991
Fuel source ECL, BCCL, ICML & Imported coals
Fuel requirement 2400 ton coal/day
The station uses boilers and turbo-alternator sets manufactured by BHEL.
Power generation is controlled through Digital Foxboro USA make
Intelligent Automation (IA) system.
SGS PERFORMANCE LANDMARKS ACHIEVED IN 2005-06:
o Highest daily MU generated: 3.473 MU
o Highest daily station plant load factor: 107.19 %
(100% PLF = 3.240 MU)
o Lowest monthly auxiliary consumption: 8.40%

UNIQUE FEATURES:
 1ST
TPS in India to achieve ISO 9001 certification (Certified in the year 1997).
 1st
CESC TPS to achieve ISO 14001 certification (Certified in the year 1997).
 1st
CESC TPS to achieve OHSAS 18001 certification (Certified in the year 2007).
 1st
TPS in India in lower installed unit category (≤110MW)to be ranked within top 10
TPS in India on % Plant Load Factor (PLF) achieved in last 6 years (as per CEA).
 Installation of “Zero Discharge System” during the year 1995, first in India.
 Installation of 2 number of 15 KW Micro-Hydel sets at CW outfall (1st
in February
2011 & 2nd
in December 2011) & installation of 3rd
Micro-Hydel sets is on progress.
ENERGY SAVING INITIATIVES:
 Installation of Variable Frequency Drive (VFD) of unit 1 ID & unit 2 ID fans.
 Vane damper lins of PA fans from existing single vane control for reducing throttling
loss.
 Replacement of BFP passing re-circulating valves by existing repaired re-circulation
valves.
 Installation of flexible seal and acoustic cleaning system in both units air heaters to
reduce air leakage loss and eliminate steam consumption.
 Auto-cut off timer introduced in power supply system to all officers’ room after 8:00
pm.
 Installation of 3.2 KW solar PV module.

UNIT 2
PLANT SPECIFICATION
MAIN BOILER GENERAL SPECIFICATION
Manufacturer M/s BHEL
Type Fusion welded walls water cooled Single
radiant furnace, Single drum and natural
circulation, balanced draft furnace, tangential
fired, hopper bottom, top supported,
pulverized fuel fired boiler.
Identification No: U-I:WBL 11150
U-II:WBL 11151
Furnace Specification
Type Fusion welded walls water-cooled Single
radiant, hopper bottom and natural circulation
Wall Water steam cooled
Total SH space projected area 2836m2
Depth 7,696 mm
Width 10,135 mm
Height 28740 mm
Volume 1,819 m3
Drum elevation 36.3 m from basement

STEAM GENERATOR:(Boiler MCA = 77 MW)
STEAM:
Table: Steam Specification
DESCRIPTION UNIT H.P. HEATERS IN
H.P.
HEATER
S OUT
MC
R
75 %
MC
R
60 %
MCR
MCR
Flow at SH O/L t/h 318 238.5 191 285
Pressure at SH O/L Kg/Cm 2
g 89.5 89.5 89.5 89.5
Pressure at LTSH
O/L
Kg/Cm 2
g 97.9 94.2 92.5 96.3
Pressure in drum Kg/Cm 2
g 102.
6
96.9 94.2 100
Sat Temp. in drum o
C 311 307 302 310
Temp. at LTSH O/L o
C 385 380 374 407
Temp. at SH Platen
Inlet
o
C 338 336 333 319
SH Platen outlet o
C 394 398 401 376
SH Finish outlet o
C 515 515 515 515

PRIMARY AIR FANS
Manufacturer: BHEL
DESCRIPTION
UNIT
VALUE
Type:
(NDV 17 TARANTO) Radial
Single suction, single stage centrifugal with spiral casing handling hot air.
Location: Ground mounted
Medium handled: Hot air
Orientation:
Bottom horizontal delivery and 45 degree inclined suction.
NOS. / UNIT NOS. FIVE (5)
Design Rating
a) Capacity m3
/s 19.0
b) Total head
developed
mmw
c
680
c) Design Temp. O
C 305 O
C
d) Specific weight of
medium
Kg /
m3
0.605
e) Speed rpm 1480 rpm
Fan reserve Flow % 38
Pressure % 25.9
Control: Inlet multiple damper control or louver damper control.
Motor specification: BHEL, squirrel cage induction motor
6.6 KV, 3 phase , 50 HZ, 1500 rpm , clockwise rotation, 190 KW
Class of insulation: Frame size: 1LA 7566
Table2.2: Primary Air fan specification

ELECTROSTATIC PRECIPITATOR
Manufacturer: BHEL
SL.
NO
DESCRIPTION UNIT VALUE
1
Design conditions:
a Gas flow rate m3
/sec 143.38
b Temperature Oc 140
c Dust concentration Gms/Nm3 67.92
2 Type of precipitator FAA-5x37.5-90125-2
3 Number of precipitator offered per boiler 2
4 No of gas path per boiler 2
5 No of fields in series in each gas path 5
6 Guaranteed collection efficiency for design
condition
% 99.78
7 Velocity of gas at electrode zone on total area m/sec 0.64
8 Treatment time sec 29.4
9
Collecting electrode:
a No of rows of collecting
electrode per field
31
b No of collecting electrode
plates. Five plates are
arranged in each row per
field
155
C Total no of collecting plates
per boiler
1550
d Nominal height of collecting
plate
m 12.5
Table 2.3: ESP Specification

TURBINE & AUXILIARIES
TURBINE SPECIFICATIONS:
Maker: BHEL. Hyderabad
Maximum output: 77 MW.
Most Economical output: 70 MW.
Type: Single cylinder, condensing steam
turbine of design rating 70 MW with 5
non-regulated extraction points of
steam for heating the feed water and
directly driving the alternator.
Suitable for system frequency: 47.5Hz to 51Hz
Inlet Steam Pressure (Normal) 86 atm
Inlet Steam Pressure (Max) 90 atm
Inlet Steam Temperature (Normal) 510 ºC.
Inlet Steam Temperature (Normal) 535 ºC.
Main steam pr at ESV 80 kg/ cm2
MS temp before stop valve 510 ºC.
Absolute pressure at exhaust 0.098 ata.
Turbine cycle efficiency 35 %
Cooling Water Temperature 31 ºC.
Inlet Steam Flow (for 70 MW) 279.153 T/hr.
Normal exhaust steam pressure 0.098 ata
Cooling Water Temperature 31O
C
Inlet Steam Flow (for no load) 4.7 T/hr.
No. of control valve four nos. at H.P. inlet
Direction of rotation clockwise viewing towards generator
from front bearing pedestal.
No of extraction points 5

Speed
Rated speed 3000 rpm.
Turbine tripping Speed 3300 rpm.
Critical speeds:
First critical speeds of:
a) Turbine rotor 2170 rpm
b) Alternator 1788 rpm
c) Combined critical speed 1894 rpm (Generator)
2156 rpm (Turbine)
Second critical speeds of:
a) Turbine rotor 6714rpm
b) Alternator Beyond 4000 rpm
c) Combined critical speed 5627rpm (Generator)
8376 rpm (Turbine)
2.6.3 Flow Data (T/Hr.):
DESCRIPTION MIN
(NO
LOAD)
DESIG
N
(70
MW)
MAX
(77M
W)
Main steam throttle
flow
4.7 279.153 313.68
8
5th
extraction (HPH 2) 0 22.902 26.539
4th
extraction ( HPH
1)
0 11.086 12.822
3rd
extraction (
Deaerator)
0 20.002 23.020
2nd
extraction (LPH
2)
0 9.049 10.308
1st
extraction (LPH
1)
0 17.161 19.194
Table: Flow Data

UNIT 3
WORKING STEAM CYCLES IN POWER PLANT
WORKING
A steam power plant continuously converts the energy stored in fossil fuels (coal, oil,
natural gas) or fissile fuels (uranium, thorium) into shaft work and ultimately into electricity.
The working fluid is water, which is sometimes in the liquid phase and sometimes in the
vapor phase during its cycle of operations.
So, it can be said easily that a
fossil fueled power plant is a
bulk energy converter from fuel
to electricity using water as the
working medium. Energy
released by the burning of fuel is
transferred to water in the boiler
(B) to generate steam at a high
pressure and temperature, which
then expands in the turbine (T) to
a low pressure to produce shaft work. The steam leaving the turbine is condensed into water
in the condenser (C) where cooling water from a river or sea circulates carrying away the heat
released during condensation. The water (condensate) is then fed back to the boiler by the
pump (P), and the cycle goes on repeating itself. The working substance, water, thus follows
along the B-T-C-P path of the cycle interacting externally as shown above.
If we go through the cycle internally, we will see that Carnot cycle is the most ideal
steam power plant cycle, as it offers the greatest efficiency possible between any two given
limits of temperature. But this cycle, applied to a steam power plant, is practical up to a point.

Figure 3.1Carnot Cycle on p-v
The isothermal generation of steam in the boiler (process AB) with volume expansion
from VA to VB is reasonable. Also reasonable is the adiabatic expansion of the steam in the
turbine (process BC).
The impractical part of this cycle is in the handling of steam in the condenser and feed
pump. Steam is only partially condensed in the condenser and the condensation must cease at
D. Furthermore, the feed pump must be capable of handling both wet steam and waste. And
this is not possible. So, this can be called as an ideal cycle but not a practical cycle and that is
why the Carnot cycle is not adopted in steam power plant.
A slight modification of this cycle makes it more practical, but then it will give rise to
lesser thermal efficiency than the Carnot cycle. This modified cycle is termed as Rankine
cycle, where instead of stopping the condensation in the condenser at some intermediate
condition; the condensation is allowed to continue until it is complete at point D, shown in
Fig. 3.2.At this point there is all water. This condensate can be successfully dealt with in the
feed pump pumping it to the boiler at boiler pressure PB.
Figure 3.2Carnot Cycle on T-s

In the Rankine cycle, heat is added reversibly at a constant pressure but at infinite
temperatures. If Tm1 is the mean temperature of heat addition as shown in Fig. 6, then the area
under 4 and 1 is equal to the area under 5 and 6. Then, we found the efficiency of this cycle is
Rankine = 1 – (T2/Tm1),
Where T2 is the temperature of heat rejection.
The lower is the T2 for a given Tm1, i.e. lower is the condenser pressure, and the higher
will be the efficiency of the Rankine cycle. But, the lowest practicable temperature of heat
rejection is the temperature of surroundings, T0. The saturation pressure corresponding to this
temperature T0 is the minimum pressure to which steam can be expanded in the turbine. This
being fixed by the ambient conditions,
Rankine = f (Tm1)only
So, the higher the mean temperature of heat addition, the higher will be the cycle
efficiency.
Thus, to increase the mean temperature of heat addition the concept of “Superheat”
comes. From Fig. 6 it is clear that, when the initial state changes from 8 to 1, Tm1 between 4
and 1 is higher than Tm1 between 4 and 8. If we further increase the initial state from 1 to
some higher point, it will result higher Tm1 than before. So an increase in the superheat at
constant pressure increases the mean temperature of heat addition and hence, the cycle
efficiency. Moreover, with increase in superheat, the expansion line of steam in the turbine
Figure 3.3Rankine Cycle on T-s
diagram
Figure 3.4Mean Temperature of Heat
Addition and Superheat in Rankine
Cycle

shifts to the right, as a result of which the quality of steam at turbine exhaust increases and
performance of the turbine improves.
Apart from this Rankine cycle many other cycles are adopted in steam power plants, viz.
Reheat cycle, Regenerative cycle, Reheat-Regenerative cycle etc., to increase the overall
cycle efficiency and as well as plant efficiency. In “SGS” only regenerative cycle is used.
Why is this Regenerative cycle adopted?
There is a large difference between the superheated steam temperature as supplied from
the boiler unit to the turbine and the condensate temperature as it leaves the condenser and is
recycled to the boiler as BFW. Now to increase the condensate temperature on it’s way back
to the boiler and, as a consequence, to increase the thermal efficiency of the plant, the process
of regenerative heating (feed heating) is introduced.
In this process, small quantities of steam drawn at various stages of the turbine are
allowed to pass through several feed heaters whereupon they condense in the process of
either direct heat exchange or indirect heat exchange with the condensate being pumped to
the boiler. The bled steam condenses and heats up the turbine condensate, which together
with the bled-steam-condensate is returned to the boiler.

UNIT 4
FUEL HANDLING SYSTEM
Fuel handling system consist of two part (a) coal handling plant (b)fuel oil system.
COAL HANDLING PLANT
Fig 4.1 Coal Handling Plant
Here, both types of coal (ECL and ICML) are used. ICML coal contains 47% ash ECL coal
contains 22-25% ash. ECL (Eastern Coal Field Ltd)coal mainly coming from Ranigang belt,
it is more costly than the ICML coal(coming from RPG‘s mines, Sashatali mine, Barabani
mine only, use of ECL coal means good generation but per unit charge is increased & only
use of ICML coal means difficult to handle flame stability & more ash generation. For this
resin blended coal (ECL + ICML) is used to generate electricity.
Coal is unloaded from the wagon by tripling the wagon. The unloaded coal from the
wagon falls on six no’s of hoppers. From the hoppers it falls into the conveyor 1A or 1B
trough vibrating feeder to regulate the coal flow and decrease the impact on conveyor.
Conveyor 1A or1B convey the coal to the transfer point 1 where the coal is transferred to
conveyor 2A or 2B through flap gate FG1 or FG2. From the conveyor 2A or 2B the coal is
transferred to the conveyor 3A &3B at transfer point 2. The conveyor 3A &3B transfer the
coal to RBFD1 or RBFD2 (RBFD – Return belt feeder drive). RBFD1 or RBFD2 convey the
coal to screen1 & screen2 to screen the already sized particles through ILMS (ILMS –
Inline magnetic separator) to separate the magnetic particles. The already sized particles

falls on the conveyor 4A or 4B through 2 no’s of Ring Granulator (Crusher) to get a size
approximately 20mm. From the crusher house the crushed coal around 20mm size falls on
the conveyor 4A & 4B which has Metal Detector. Conveyor 4A & 4B convey the coal to the
conveyor 5A & 5B. Conveyor 5A &5B finally enters the bunker house which has Tripler
Trolley to fill 5 no’s of Raw Coal Bunker.
RBFD1 or RBFD2 rotates in opposite direction for blending the coal at the field
where 2 kinds of coal are stored & blended. During the reverse rotation of RBFD1 or
RBFD2 the uncrushed coal falls on the conveyor 6A or 6B. The coal of conveyor 6A & 6B
falls in open field to make a stock pile of uncrushed coal through chute1 & chute2. The
uncrushed coal is reclaimed by Reclaim Hoppers. One set of Reclaim Hopper guide the
uncrushed coal to conveyor 8 through vibrating feeder. The conveyor 8 conveys the coal
to conveyor 2A or 2B at transfer point 1. Another set of Reclaim Hopper guide the
uncrushed coal to conveyor 7 which convey the coal to conveyor 3A & 3B at transfer point
2. In rainy season coal is wet condition & field contains enough water. To remove this
water from the coal & field some process are used:
(a)The coal in stored in the form of pile(height<5m) so the water with coal comes down
ward direction due to gravity then the dry coal from upper portion is separated by
bulldozer .
(b)the geo filtered pipes are spread out throughout the field to collect the water & send to
the suction of the pump to throughout from the field. But it has no enough capacity to
drained out the water & also if geo filter unable to supply the sufficient quantity of water
to the suction of the pump then may damage .so another process
(c) Saucer drain system is used it is nothing but outside inclined drain.

FUEL OIL SYSTEM
The main purpose of Fuel Oil System is to facilitate start-up of the boilers, flame
stabilization at low load /unstable flame condition with pulverized coal as the fuel. The
fuel oil system, in addition to serving this purpose, is also capable of carrying about 20%
of boiler MCR load. The heavy fuel oil, which shall be used during normal operation,
being quite viscous requires being preheated to attain requisite viscosity at the burner
for proper atomization and combustion. In addition to the HFO, supply of Light Diesel Oil
(LDO) is also provided for initial lightning up of the furnace during cold start –up before
with HFO. But here now only LDO is used, all HFO system is used for LDO.
LDO SYSTEMS:
The LDO is pumped to the burner floor by two motor driven screw type positive
displacement pressurizing pumps which takes suction from the LDO storage tanks via 2
basket type suction strainers. Normally one strainer and one pump are in operation while
the other remains as standby. A recirculation line is provided at the discharge side of the
pump through a pressure control valve. The recirculated oil returns back to the LDO
storage tank. The LDO discharge from the pressuring pumps is led to the burner front
through a fuel oil control station which maintains oil supply to burner at a preset pressure
at its downstream irrespective of the number of burners in operation.
THE MILLING SYSTEM:
The coal firing equipment is suitable for attaining full load of the boiler on the limit coal
with three (3) mills in operation and with two (2) mills in the operation when guarantee coal
is fired. Coal from the coalbunkers is fed to the pulverizer through a coal feeder.
FEEDER
Here gravimetric feeder is used to feed the coal to the mill. in
this type of feeder give accurate mass flow rate of the coal
may be bulk density or volume may be changed. Here the
coal flow rate is obtained by
R=MXN
R=MASS FLAW RATE
M=MASS OF THE COAL ON UNIT LEANTH OF
FEEDER BELT
Fig: Gravimetric Feeder

The gravimetric resembles a belt feeder in the coal conveying aspect but provided with
precise weighing system to measure the mass of coal per unit length of belt which is
multiplied by the speed of belt to determine the rate of coal flow. The weighing can be done
by either mechanical or electrical device.
Here 5 feeders are used (A, B, C, D, E) to feed the mills. Each mill is feed by each feeder.
Coal Feeders:
a) Number of feeders : 5 x 33.33%
b) Type : Gravimetric feeder
c) Capacity : 28 t/h
d) Gear Box ratio : 213 : 1
e) Motor speed : 1450 rpm
Fig 4.5: Gravimetric feeder at SGS Fig 4.3: Conveyer belt
MILL
Here bowl mill is used to pulverize the coal. The size of the coal such that 70% should
pass through the 200 mesh sieve.
In this type of mill 3 roller journal assembly & a rotating bowl is used to crush the coal.
when coal fall on the bowl from middle pipe and outward direction and coal take entry in
middle gap of roller & bowl (initial gap=5mm).20mm sized coal take entry between the gap
by uplifting the roller forcefully so the spring assembly (in journal head is compressed & give
a reaction impact on the coal & due to the rotation of bowl roller also rotated in opposite
direction so a attrition is also given to the coal. Due to this two effect coal is pulverized and
conveyed to the coal burner through PA produced from lower side of the mill.

Classifier is used to given pass to go the desired size of the coal & other coal is
returned back to the bowl for further pulverizing.
Seal air is given from bottom direction to prevent the damage of bearing from the coal
dust. Seal air pressure is more than the PA pressure.
Mills:
a) Number : 5 x 33.33%
b) Type : Bowl Mill
c) Maximum capacity : 22 t/h
d) Air flow per mill : 37.3 t/h
e) Pulverized coal fineness through 200 mesh : 75%
f) Mill inlet temperature : 66 C to 90 C
g) Mill outlet temperature : 191 C
h) Motor rating : 260 kW
i) Motor speed : 1000 rpm
j) Coal burner elevations : 5 (A, B, C, D and E)
k) Number of burners per elevation : Four
Fig: Schematic of bowl mill
Fig: bowl mill

UNIT 5
WATER TREATMENT PLANT
INTRODUCTION
The availability of a suitable
supply of water (both for Cooling
purpose and Boiler feed make-up)
is one of the basic requirement in
sitting a Power Station. In this
sense, water may be regarded as a
raw material for the Power
Generation Industry.
And, inadequate water
treatment and insufficient
theoretical knowledge of Scale
formation and Corrosion process had been a major cause of Boiler Explosion, which occurred
in the early years. In this section, we are going to review the field of water treatment in
relation to Boiler Operation.
The overall objective in any regime of control in Power Plant Systems is to maintain
operation at best possible levels of availability, economy, and efficiency. To attain this
objective, Chemical Control of the Water & Steam is directed to:
 Prevention of corrosion in the Boiler, Steam and Feed Water systems.
 Prevention of Scale and Deposit formation on wetting surfaces.
 Maintenance of a high level of purity for Feed Water.

PROCESSES FOR PRE-TREATMENT OF WATER
The main raw water source of SGS is River HOOGLY.
ALUM DOSING:
These colloidal impurities are removed by coagulating with Alum [K2SO4, Al2(SO4)3
18H2O]. This is due to the presence of these negatively charged colloidal particles, that river
water looks heavy, i.e. gives the indication of turbidity in water.
SODIUM HYPOCHLORITE ADDING:
Sodium Hypochlorite acts as a substitute for Chlorine Gas.
Sodium Hypochlorite bleaches by oxidation and thus plays a key role in destroying bacteria
present in the river water. Thus, white amorphous powder having a strong smell of chlorine
evolves Cl2 by reacting even with carbonic acid present in moist air.
2NaOCl + 2H2CO3 =2NaCO3 + 2H2O+ Cl2
(Sodium Hypochlorite)
The evolved chlorine reacts with moisture liberating nascent oxygen and HCl. This
nascent oxygen thus oxidizes the coloured vegetable (organic) matter, producing a colourless
product.
Cl2 + H2O = HCl + HOCl
HOCl = HCl + [O]
Cl2 + H2O = 2HCl + [O]
(Nascent oxygen)
[O] Oxidation
So, Coloured Vegetable Matter --------------------- Colourless Product
This nascent oxygen also destroys big organic acids into small acids; otherwise big
organic acids destroy the resin bed.

FM (FLASH MIXTURE) TANK
The flow rater of Flash Mixture tank is 150 – 250m3
/h.
Here the turbidity is 250-750 NTU It is a tank Ganges
water which is coming after strainer by CW pump mix
with alum solution, poly electrolyte and Sodium hypo
chlorite. One agitator with motor drive is present in the
FM tank. Two numbers of FM tank is used at the time of
entry of the FM tank three dozing are connected with
half-inch diameter pipes. The inlet pipe is connected at
the bottom of the tank. The tank is separated in three
parts. In the middle part the water is agitated and after
that it goes to the separated chamber. From the top of
the chamber the mix water goes to the plate settler. At
the bottom, heavier mud particle are pumped to the mud
collecting pond. Two numbers of ponds are used. Fig 5.1: Inline flash mixture
Flash Mixture Tank

PLATE SETTLER
In the plate settler tank there is some inclined plate. At the bottom of the plates there are
conical chamber for collecting mud. the water coming from FM tank take entry from upper
side of the PS but it again rises by touching plate bodies .it create resistance in path of water
but mud fill more resistance to go up so due to the gravity it comes down but water goes up
& over flow water goes to the storage tank. The inclination of the plates is 670
with
horizontal. Here the turbidity is 3-5 NTU. The mud particle is collected at the bottom & goes
to the mud collecting pond.
Fig 5.3: Inclined Plate settler
PRETREATED WATER STORAGE TANK:
This clarified water after the PLATE SATTLER goes to the Clarified Water Storage
Tank. This clarified water used for different purposes. For this several pumps are employed
viz., 3 DM Water pumps, and three NON DM Water pumps. All these pumps take suction
from the CW Storage tank through that suction header.
DM Pumps deliver the pre-treated water to the main DM house, where the water is
subjected to overall Demineralization process. Here the water passes through several filters.
Generally two filters of the same kind (one operating and one standby) are used. In the next
section, we discuss about the several process for Demineralization.

PROCESSES FOR DEMINERALIZATION OF WATER
The type of Demineralization chosen will certainly depend upon some factors, four of which
are:
 The quality of raw water
 The quality of final treated water, i.e. the degree of de-ionization required
 The capital cost, and of course
 The running cost
DM water tank
Nos. : 2
Diameter : 8000 mm
High / Deep : 7500 mm
Material : MSRL
DM water pump
Maker : Akay Industries
Nos. : 2+1
Model : 4 x 3 – 9 CHP -M
Type : Centrifugal
Capacity : 75 m3/Hr
T.D. Head : 25 MWC
Material of construction SS 316
Medium : DM water
Motor HP : 15
Motor RPM : 2900

BY PRESSURE FILTER & ACTIVATED CARBON FILTER:
None of the pre-treatments can remove all the organic matter. We aim at removing as
much possible of the organic substances, some of which are in true solution while others in
colloidal dispersion; so that they do not interfere with the later stages of the treatment
process.
To ensure this, it is necessary to convert as much as possible of the soluble material to an
insoluble form and remove it along with the less soluble constituents by Sedimentation and
Filtration. The Pressure Filter and the Activated Carbon Filter plays a key role in this
respect.
In Pressure Filter silica is used as the filtering medium. Here water is pressurized and as
it passes through the filter, the fine impurities are separated from the water. After this filter
water is passed through the Activated Carbon Filter (A.C. Filter), where the excess
chlorine present in water, is absorbed. Maximum permissible limit of chlorine after this filter
is 0.3 ppm.
BY CATION EXCHANGER:
After the filters, the water enters the ion exchanger. The use of Synthetic Ion
Exchange Resins can completely remove all the ionisable salts present in the water. The
resins (organic), which are used to remove the metallic ions or the cations from water, are
called ‘Cation Exchangers’.
This is the organic structure of Polystyrene Sulphonate, an example of the cation
exchange resin. Now, instead of --SO3H group the cation exchange resin may also contain –
COOH group in their giant organic structure. Thus the cation exchanger contains H+
ions

obtained usually from these –SO3H or –COOH groups present in their molecules. Thus, these
types of resins may be represented by R-H+
.
Such strongly acidic cation exchange resins, will exchange hydrogen ions for other
cations. The result is that neutral salts are converted to their corresponding acids, a process
known as Salt Splitting.
2R-H+
+ CaCl2 = R2Ca +2H+
+ 2Cl--
2R-H+
+ MgSO4 = R2Mg +2H+
+SO4
2--
2R-H+
+ Ca (HCO3)2 = R2Ca +4H+
+2CO3
2--
R-H+
+ Na+
= R2Na + H+
BYWEAK BASE ANION EXCHANGER:
The resins, which are used to remove the non-metallic ions or anions from water, are
known as Anion Exchangers. The anion exchanger resins are organic amine (--NH2)
compounds of giant molecules. This type of resins can be represented by R-NH2. The resins
are synthetically prepared – they are insoluble and complex organic molecules.
So, continuing with the example of Polystyrene if basic groups are introduced into the
polystyrene resins instead of the acidic groups, the resins are conferred with anion exchange
properties. The basic group may be derived from NH3 or an amine (--NH2) and in order to
facilitate the introduction of the basic group into the polymer, it may first be produced to
contain for example chloro-methyl groups.
The resins containing primary, secondary, and tertiary amine basic groups behave as
weak bases. Thus, such Weak Base Anion Exchangers will exchange, or (more correctly)
form acid salts with strong acid only. At first the resin R-NH2 in contact with water is
converted to R-NH3
+
group with basic OH–
attached to it.

R-NH2+H – OH = RNH3
+
+ OH--
RNH3
+
OH--
+ Cl--
= RNH3Cl  + OH--
2RNH3
+
OH--
+ SO4
2--
= (RNH3)2SO4 + 2OH--
H+
+ OH--
= H2O
BY DEGASSER TANK:
Water now passes through the Degasser Tank. Here the blower blows air into the chamber
and as a result unstable carbonic acid of the water breaks to liberate CO2 gas.
H2CO3 = CO2 + H2O
Thus water becomes free of carbonate ions (CO3
2-
), which was not precipitated as salt by
the weak base anion exchanger.
By STRONG BASE ANION EXCHANGER:
After the Degasser Unit the water now passes through the Strong Base Anion Exchanger.
The resins containing quaternary ammonium groups, are strongly base, similar in strength to
strong alkalis and will exchange even weak acids like carbonic acid and silicic acid, or in
effectCO2 and SiO2 in water. However, when water passes through the strong base anion
exchanger, the harmful silicate ions are absorbed and the anions, which have not been
absorbed earlier, are absorbed here.
R-NH2 + H – OH = RNH3
+
+ OH--
2RNH3
+
OH--
+ SiO3
2--
= (RNH3)2SiO3 + 2OH--
Thus, we find weak resins have only a limited capability for ion exchange and since
strong resins will perform all of the functions of weak resins, there would appear to be little
point in using them.

UNIT 6
BOILER
INTRODUCTION
According to the Indian
Boiler Act. 1923, a Boiler (Steam
Generator) is a closed pressure
vessel with capacity exceeding
22.75 liters used for generating
steam under pressure. It includes
all the mountings fitted to such
vessels that remain wholly or
partly under pressure when steam
is shut-off.
The Steam Generator (Boiler)
is the major part of a Thermal
power plant, which provides the
energy required for consequent
steam generation. The furnace
Boiler At SGS
of the boiler creates the environment for combustion of pulverized coal particles, fed to it
from coal mill leading to the formation of flue gas, which in turn contributes for the entire
heat value required in the plant. The Steam Generator (Boiler) mainly comprises of two parts
namely the First Pass and the Second Pass. Both the First Pass and the Second Pass is a
box like structure with a hopper fitted below. The Boiler walls are made up of tubes hanging
vertically from top. The walls of the First Pass are made of water tubes and that of the
Second Pass are made of steam tubes.

The Steam Generators (Boiler) in SGS are of
radiant, natural circulation, single drum, and p.f. fired,
balanced draft, , corner fired double pass, non-reheat,
semi-outdoor type designed to fire pulverized
bituminous coal as fuel.
The Boiler is provided with fuel oil burners for
initial start-up and low load operation and pulverized
coal (main) burners for normal operation. Slag (ash) is
removed from the furnace chamber continuously
through bottom ash hopper by ZERO DISCHARGE
SYSTEM.In short the design parameters of the Boiler
– Unit 1 & 2 are listed below: super heater coil
BOILER SYSTEM:
Operating parameters at MCR (Maximum Continuous Rating):
a) Steam Flow : 318 t/h
b) Pressure at superheater outlet : 89.5 kg/cm2
c) Drum pressure : 102.6 kg/cm2
d) Temperature at superheater outlet : 515ºC
e) Feed water temperature : 229ºC
f) Secondary combustion air temperature : 339ºC
g) Fuel quantity
: 57.1 t/h
h) Air quantity : 354 t/h
i) Temperature of gas at boiler exit (Chimney) : 143ºC

BOILER CONSTRUCTION
At the present time the water cooled furnace is applied to practically every type and
size of Boiler. We are trying to discuss about the every parts of this Boiler of SGS below:
FURNACE:
Furnace is the primary part of Boiler where the chemical energy available in the fuel is
converted to thermal energy by combustion. Major factors that assist for efficient combustion
are Time of residence (of fuel) inside the furnace, Temperature inside the furnace and
Turbulence that cause rapid mixing between fuel and air. Thus, furnace is designed properly
for efficient and complete combustion. The various particulars of the furnace are given
below:
WALL CONSTRUCTION:
The furnace walls are composed tubes. The tubes are spaced on close centers. Where
the tubes are spread out to permit passage of superheater elements, hanger tubes, water-
cooled spacers, etc.
BOTTOM CONSTRUCTION:
Two furnace water walls, usually the front and rear walls are continued down to form the
inclined sides of the bottom. Depending on the height of the furnace, some clearances
between the furnace and ash hopper is allowed for downward expansion of the furnace walls.
Leakage of air at this point is prevented by either a water seal arrangement called as trough
seal.
BOILER DRUM:
The steam drum is of fusion-
welded design with welded
hemispherical dished ends and
suspended from ceiling girders
with u rods. The feed water
distribution manifold is at the

bottom of steam drum and admits feed water through holes in the manifold, distributing the
flow of water evenly along the whole length of the drum. The discharge is directed along the
bottom of the drum and toward down comers.
The drum has two compartments, i.e., one circumferential for wet steam and central for
water and separated steam. Separated steam is dried in the baffle plate demisters, which are
built on the cyclone separators and along the drum length just before the steam outlets.
An emergency overflow is provided in order to protect against priming in case of water
overfeeding.
THE DETAILS OF THE BOILER DRUM OF UNIT 1 & 2 OF THIS PLANT IS GIVEN BELOW
Boiler Drum:
a) Outside diameter : 1675 mm
b) Overall length : 10.2 m
c) Design drum pressure : 110 kg/cm2
d) Operating temperature : 311ºC
e) Elevation : 36.3 m
Required water quantity for filling:
a) Drums : 25 m3
b) Water wall plus down comer tubes : 35 m3
c) Superheater (all types) : 40 m3
d) Economizer : 20 m3
BOILER AUXILIARIES
These are the devices incorporated in the Boiler circuit to boost up the efficiency and
performance of the steam generation plant and assist in the systematic and adequate operation
of the Boiler unit for prolonged period. The details of the Auxiliaries are discussed below:
ECONOMISER:
For efficient heat exchange in the economizer the mean temperature difference
between the gases and the water is to be greatest with a counter flow system, the coldest
water entering economizer section meets the coldest gases leaving the section.

The economizer consists of tube banks situated in the second pass of the boiler. The
banks are built-up layers of horizontal tubular coils fixed on the hanger tubes. Adequate space
is provided between tubes banks to facilitate ONLOAD cleaning.
SUPERHEATER:
The steam after being separated in the drum from the water and steam mixture flows as
per the attached diagram. For higher temperature requirement convection sections are
arranged essentially for pure counter flow of steam and gas, with steam entering at the bottom
and leaving at the top of the pass, while gas flow is in opposite directions. The arrangement
allows a maximum mean temperature difference between the two media and minimizes the
heating surface. The second stage of the super heater is made up of tube element, platens
hung at the inlet to the interconnecting section. It takes radiant heat from the furnace.
The third stage of the super heater consists of vertical tube elements hung over the
furnace arch and in interconnecting pass. The arch is used for protection of the tube elements
against direct flame radiation. In order to maintain metal temperatures of the outlet sections
of tube elements within the recommended limits, the flow of steam and combustion gases in
this stage are in same direction.
Cross-sections of the convection passes have been dimensioned so that gas velocities do not
exceed the value of pre-set value. Since the concentration of the fly ash in the combustion
gases can reach a relatively high value, tube elements situated at the inlet to the second pass
where local flow disturbances normally occur, are especially protected against the excessive
fly ash corrosion. The protection measures include fitting of anti-corrosion shields to the first
row of the elements and adding allowances to the thickness of all elements of the tube bank
of the economizer. Additional protection anti-corrosion shields of the superheating surfaces in
the area near soot bowers are provided.
Due to this steam flow through the inside of superheater tubes and hot flue gas flow
through the outside of the tubes, the metal temperature of the superheater varies from point
to point and a careful observation is taken in this respect.

AIR PRE-HEATER:
The Air Pre-Heater is an essential boiler auxiliary, because hot air is necessary for rapid
and efficient combustion in the furnace and also for drying coal in the milling plant. This is
rather different from its original purpose, which was to recover ‘waste’ heat from the flue gas
to increase boiler efficiency.
In SGS regenerative type rotary Air Pre-Heater is used, where the heating sheets being
mounted on the rotor are alternately, heated by the flue-gas stream, and cooled by the air
stream. The rotor is divided into two main parts i.e. the middle one together with the upper
and lower shaft and the outside one, which, in turn, is made up of two segments. The middle
part of the rotor includes a hub to which the radial sheets are welded.
Sealing of the heater prevents any air ingress into flue-gases, it is provided with a system
of flexible tapes, which are rubbing against the co-working parts as the rotor turns. To
compensate for thermal deformations of the rotor faces an articulated system of wings and a
lever system have been adopted. There are types of seal (a) Rotor seal, (b) Longitudinal
seal, (c) Axial seal, (d) Radial seal, (e) Lateral seal, (f) Circumferential seal.
Air Pre-Heater:
a) Number of units : 2 x 50%
b) Type : Regenerative Bisector
c) Motor Rating : 5.5 kW
d) Motor speed : 1450 rpm
SOOT BLOWERS:
Because of the nature of the deposits resulting from the combustion of coal, and to a
relatively smaller extent from oil, means have to be provided to prevent an accumulation of
deposits from chocking the Boiler gas passes and to maintain the Boiler heating surfaces in a
suitably clean condition for effective heat transfer whilst on-load. The most commonly used
method of on-load cleaning is Soot Blowing, although other methods such as shot cleaning
on economizers and tabular air heaters have been used to a more limited extent on other
Boilers.
The Soot-Blowing can be with steam or compressed air; both are equally efficient.
Normally for all the two Boilers in SGS, superheated steam is used. The steam tapping is
taken from any of the intermediate superheater header. The enthalpy of superheated steam is

selected such that after the steam pressure is reduced to the blowing pressure. The steam will
have enough superheat. This limitation is to avoid the use of alloy steel piping. About 500C
superheat is preferred to prevent the water particle being blown through the nozzle, which
may lead to tube cutting and consequent tube failures. The steam taken from the intermediate
header is reduced through a pressure-reducing valve to approximately 25 to 30 atmospheres
and this steam is directly fed to the soot-blowers. A separate line from the pressure reducing
station is taken to the air heater so that the air heater soot-blowers can be used along with the
soot-blowers in other areas. Normally the soot-blowers are operated one by one. Hence, the
piping is sized for the maximum flow required for any of the soot-blowers. The lay out of the
piping is carried out in such a way that the piping is self-drained and finally ending up with
the electrically operated drain valve. This drain valve will have a permanent orifice in the
disc so that a continuous drain can be maintained. This will keep lines in the warmed up
condition and will prevent condensate formation.
BOILER FIRING SYSTEM:
Proper fuel combustion in Boiler is one of
the most important noticeable areas in all
Power Plants; as everything for electricity
generation is depend on it. Thus Boiler
Firing system is among the Boiler
Auxiliaries having great importance. The
factors influencing the type of firing to be
adopted on a Boiler is not the steam pressure
and temperature but the evaporation.
Pressure and temperature conditions are
selected to suit the steam cycle adopted and
can be applied to any method of firing. That
the more advanced steam conditions are associated with pulverized fuel (coal) fired Boilers
is only because the higher evaporations generally associated with these conditions necessitate
the adoption of this form of firing. Oil firing can be used for any evaporation and there is no
doubt that the price difference between coal and oil and the scarcity of the latter in a coal-
producing country have prevented the use of oil-fired Boilers on a much wider scale. But
instead of it, now-a-days almost every power plant is equipped with start-up oil burners to
warm up the boiler and for many other reasons, discussed just later.

PROCESS:
Each of the oil burners has one gas igniter with LPG & electric spark assisting oil during
burner starting and stopping.
In addition to the main burners for coal firing, the boiler is equipped with start-up oil
burners, which serve the following functions:
 Warming – up of the boiler.
 Farming the pulverized coal burners.
 Maintaining the flame in the furnace chamber at low loads and keeping the
flame stable during transients.
The maximum attainable boiler load when operating with all oil burners is 30% of MCR.
The basic parts of the oil burner are:
 Housing, with a cut-off gate valve and electro pneumatic servo on the air inlet
port.
 Pressure type oil lance with a steam atomizer (for the fuel oil – basic lance)
 Ignition oil burner
 Photocell.
The ignition procedure for both fuel oil and light oil is controlled by a control system.
The flame is controlled by the photocell. The photocell is mounted on the protection tube,
which is installed in the brickwork of the throat (burner box) in the position enabling control
the oil flame. The protection tube of the photocell is cooled with auxiliary air.

BOILER WATER AND STEAM FLOW PATH
Feed water is supplied to the steam drum from the economizer outlet links. The waterside of
the steam drum is connected with the furnace bottom water wall ring header through 4 down
comers.
The front and rear wall bottom headers feed the front and rear furnace wall tubes. The
furnace side walls are supplied by the two side wall bottom headers. All the bottom headers
are connected together in the form of a ring. Some tubes in the furnace rear wall supply water
to the extended side water wall inlet headers. The extended side water wall tubes terminate in
the rear section of the side water wall top header.
In addition to the 4 down comers, which are connected to the bottom, ring header, 2 more
down comers terminate at some mid elevation to supply water to 4-platen water wall bottom
header. The platen water walls are located in the radiant section of the Boiler.
Water in the tubes of front rear, side platen and extended side walls absorb heat from the
furnace. The resulting mixture of water and steam collected in the respective outlet headers is
discharged into drum through a series of riser tubes.
In steam drum separation of water and steam takes place. The separated saturated steam is
led to the superheater for superheating and the water mixes with the incoming water from
economizer.
Saturated steam from the steam generator drum is passed through banks of superheater
tubes to heat it unto the temperature of 515 C. There are three superheater section namely
low temperature, primary superheater, platen superheater and pendant final superheater. The
dry saturated steam from the drum enters the horizontal convective primary superheater
which is located in the second pass of the tem generator through roof tubes of the furnace,
intermediate headers and second pass wall tubes. From the horizontal convection superheater,
steam flows to the radiant platen superheater suspended directly above the furnace. From the
platen superheater steam then passes through convective pendant final superheater.

UNIT 7
POWER STATION FANS
INTRODUCTION
Fan can be defined as a volumetric machine, which like pumps moves quantities of air or
gas from one place to another. In doing so it overcomes resistance to flow by supplying the
fluid with the energy necessary for contained motion. The following fans are used in power
plant for Boiler House:
FORCED DRAFT FAN (F.D FAN)
It is used to take air from
atmosphere at ambient temperature
to supply essentially all the
combustion air. It can either be sized
to overcome all the boiler losses
(pressurized system), or just put the
air in furnace (balanced draft units)
Its speed varies between 600 r.p.m
to 1500 r.p.m.
Force Draft (FD) Fans:
a) Number of fans : 2 x 50%
b) Type : Radial Double Suction
c) Capacity : 62.1 m3
/sec
d) Motor Rating : 375 kW

INDUCED DRAFT FAN (I.D FAN)
It is used only in balanced draft units to suck the gases out of the furnace and throw them
into the stack. It handles fly ash laden gases at temperatures of 125C to 200C. Its speed
ranges in between 1000r.p.m.
ID Fan Details:
Induced Draft (ID) Fans:
b) Type : Radial Double Suction
c) Capacity : 92.5 m3
/sec
PRIMARY AIR FAN (P.A FAN)
It is used for pulverized system. Primary air has two functions viz., drying the coal and
transportation that coal to the furnace. This fan is usually sized for 1500 r.p.m. due to higher
pressure.
Primary Air (PA) Fans:
a) Number of fans : 5 x 33.33%
b) Type : Radial Single Suction
c) Capacity : 190 m3
/sec
SEAL AIR FAN
It is used to seal mill bearings, coal feeders and coal pipes in case of pressure type mill. It
may take air from atmosphere and supply air to mill at a pressure higher than mill pressure or
may take up suction from cold P.A. level and boost up that pressure. There may be seal air
fan for each mill or they may supply to a common duct from where air can be supplied to
mills for sealing. Its speed depends upon the type of arrangements and fan.

SCANNER AIR FAN
It is used to provide necessary cooling air to the flame scanners. When F.D. fns are
running a portion of cold air is diverted to the scanner air fans and then to the flame scanner
cooling air connections. Two scanner air fans are usually provided, one will run and the other
will remain as stand-by. When F.D fans trip the scanner air fan will draw air from atmosphere
through emergency damper. Its typical speed is 3000 r.p.m.
Scanner Air fan:
b) Type : Radial backward curved blade,
Single suction
c) Capacity : 4000 m3
/sec
d) Motor Rating : 3.7 kW
Fig: Air paths

UNIT 8
TURBINE AND IT’S AUXILIARIES
INTRODUCTION
Thermal power plants use
closed steam or water cycle to
ensure repetitive use of water. The
thermodynamic cycle used in
those plants is Rankine cycle
modified to include superheating
and regenerating feed water
heating. Main steam from
superheaters passes through
isolating valves on boiler end,
emergency stop valves, control
valves of turbine and then flows toward the inlet of the turbine.
The turbine, which is a rotating machine, then converts the heat energy of steam to
mechanical energy. In India, turbines of different capacities, ranged between 15MW and
500MW, are employed in the field of thermal power generation. The design, material,
auxiliary systems vary widely depending on the capacity and it also depends on the company,
by whom the turbine is manufactured.
Figure:Turbine system

TURBINE SYSTEM
Super heated steam
after coming out from the
boiler, enters to turbine
through turbine stop
valve, emergency stop
valves, Governing valves.
The steam turbine is
single cylinder, impulse
reaction, condensing type
with 5 non-regulated
extractions for re-
generative feed heating.
The turbine consist of 2 sections, i.e., HP turbine and LP Turbine construction ally the HP
turbine is of double casing type .the inner casing is housed inside the outer casing such that
the two are coaxial.
Stem enters first to the inner casing of HP turbine through 2 emergency stop valves and 4
governing valves. Stem gets expanded in the hp turbine from where it is re directed to inlet of
LP turbine for further expansion. The passage of steam from HP turbine to LP turbine is
provided through an annular gap between inner casing and outer casing .the HP turbine
consist of 14 stages.
In LP turbine, steam gets further expanded and finally comes condenser where it is
condensed to water by circulating water taking from near by river HOOGLY. The LP turbine
consist s of 29 stages.
The condenser is divided in to 2 separate compartments on the waterside. Each
compartment is fed with cooling water from the common header through a motorized inlet
isolating valve, and a motorized four-way valve. Circulating water returning from each
condenser compartment is discharged to the CW return channel through the 4 way valve and
a motorized outlet isolating valve.

In case of condenser tube failure or fouling in one compartment, it is possible to isolate
that compartment on the CW side in such a condition; the turbine load has to be reduced.
There is also provision for back washing of the condenser compartments by proper re –
orientation of the 4-way valve.
TURBINE SYSTEM CONSISTS OF THE FOLLOWING SUBSYSTEMS:
 Circulating water system.
 Turbine lubricating oil system.
 Turbine governing oil system.
 Turbine gland sealing system.
 Air evacuation system.
 Condensate & feed heating system.
 Condensate makeup & duping system.
 Extraction system.
Circulating water system
Raw water from river HOOGY is pumped by four 33.33% circulating water pumps to cater
the requirement for condenser cooling and other auxiliary cooling for both the units. Beside
this the CW pumps also supply water to pretreatment plant ,ash handling booster station
,service water for different areas .the ash water and fire water sums are supplied by water
from the CW discharge tunnel

From the CW inlet header for condenser cooling a line is tapped off for the auxiliary
cooling water pump suction header for each unit. Each unit has 3x50%ACW booster pumps.
ACW booster pump of each unit supplies cooling water fir the turbine oil coolers.
BFP lub oil coolers clarified water cooling heat exchangers and mill lub oil coolers .the
return from all the cooler and heat exchangers join the condenser cooling water discharge
header to the CW return tunnel.
Turbine oil system:
The operational safety of the turbine and it’s bearing in
particular; have to be insured by a definite quantity of
continuously re circulating oil. The pump which comprise
the main part of the turbine oil system, beside furnishing the
lubricant for the bearings, also provide oil volume required
for governor oil circuit and the operation of safety devises.
THE MAIN COMPONENTS OF THE SYSTEM ARE:
Oil tank:
The oil tank has sufficient capacity for holding the entire volume of circulating oil .the
sloping design of the tank facilitates the collection of impurities for easy draining off.
Auxiliary oil pumps and emergency oil pump are housed inside the tank. Tank is also
equipped with 2 oilvapor extraction fans .tank connection to main oil pump incorporates an
oil injector and a foot valve.
The main oil pump:
In normal operation the oil volume required by the bearing and the governing circuit is
supplied by the main oil pump which is coupled directly to the turbine shaft .the main oil
pump take suction from the oil tank via foot valve and oil injector.
Auxiliary oil pumps:
Two vertical type ac driven aux. Pump are provided. The principal duties of this pumps
are
1. To supply oil to the governor and lubricating oil circuit during start up during the
main oil pump takes over .
2. To work as stand by to the main oil pump n order to restore oil pressure in governing
and lubricating system in case the main oil pump fails to deliver oil at the reg. Pressure .

3. To cut into operation, during speeding down of the unit when main oil pump dis. Pr.
Falls bellow a preset value.
Hydraulic turning gear is also supplied from the disc.
Emergency oil pump:
The DC driven EOP ensure oil to all bearing when all other source of oil supply fails. It
gives the supply by passing the duplex oil filter & coolers.
Oil filter & coolers:
Two coolers & two duplex filters are used for cooling and filtration.
Hydraulic turning gear:
Turning gear is provided to rotate the turbine shaft at sufficient speed after shut down
and before start up for uniform cooling & warm up to avoid the distortion shaft system . the
ventilation of rotating blades provide uniform cooling &heating of the bottom and upper part
of the inner casing .turning gear operation the shaft is rotated by blade wheel which is driven
by the oil provided auxiliary oil pump .
Hydraulic shaft lifting system:
Hydraulic shaft lifting system reduces the break away torque during starting. So there is
a great reduction in the turning gear size. The supply of the oil is taken from the luboil circuit
if the pressure of the circuit fails then the oil supply taken from the main oil tank, a pressure
release valve is provided in the line to decrease excessive pressure. The oil comes out from
the pockets machined in to the bottom shell of each journal bearing by gear type jacking oil
pump.
Gland sealing system:
To eliminate the leakage of steam from the gland of HP side & ingress of air in the LP
side Gland sealing system is provided. Labyrinth type sealing arrangement is done in here for
gland sealing. Each gland consists of no of rings depending upon the pressure against which
it is working.
In the time of starting glands are sealed by the gland steam which is taken from the gland
steam header at a pressure 1.1ata,
it is taken from the aux steam header through a pressure
control valve .when load increased the HP side steam leakage is gradually increased then the
leakage steam of HP side is send to the LP side.

Fig:Turbine System
Condenser air removal system:
For quick evacuation of the turbo set during starting, a single steam jet hogging air
ejector has been provided which sucks air from the condenser and turbine casing and helps in
building up the desired vacuum in the system.
To remove air leaking into the condenser during normal operation, two steam jet air
ejectors each of 100% capacity is provided.
breaking of vacuum and bringing the turbine to reset quickly under certain emergency
condition, vacuum breaker valve is provided on the air line which if operated will bring down
the turbine speed fast.
Fig:Air Removal System

BEARINGS
A turbine employs thrust and journal bearings. The thrust bearing positions the rotor
axially with respect to the stationary parts while absorbing load due to steel thrust on the rotor
and the journal bearings positions the rotor shaft radially in turbine casing, support weight of
rotor , and absorb the vertical and transverse loads on rotor.
Both bearing blocks are supplied with lubricating oil from the pressure piping. Apart from
the oil supply connections, the blocks are also provided with drain connections, which
provides the passage for the oil to return to the tank.The bearings are of slide type with an
inlay of white metal coat. They can get inclined in ball surfaces for the purpose of adjustment
toward the shaft elastic line.
The turbine front and thrust bearings are connected in one part and placed in front
bearing block.
AXIAL SHIFT
Due to the axial thrust produced on the Curtis wheel or first few stages by the high-
pressure steam entrance the turbine may be subjected to considerable stresses, which can
cause the rotor and rotor shaft to be affected. To eliminate the chances of stresses to be
produced the rotor shaft has a provision that it can sift to a certain amount from its original
position. This axial movement of he shaft is called as the Axial Shift of the rotor.
TOTAL & DIFFERENTIAL EXPANSION:
Total expansion is the expansion taken place in the casing structure due to excess heat.
Differential expansion is the difference of expansion taken place in the stator and the rotor.

UNIT 9
ASH REMOVAL SYSTEM
Bottom Ash Removal System
Here for removal bottom ash “Zero Discharge System” is used. In this system
overflow transfer tank, overflow transfer pump, two numbers of hydro bin, one number of
settling tank, one number of surge tank, three HP pumps, two LP pumps, ejector and three
number of surge recirculation pumps are present.
The bottom ash hopper filled with the water. When the bottom ash come into the
contact of water it forms clinker then the ash passes through flap gate and goes to the clinker
grinder to reduce the size of the clinker formed ash. After clinker grinder it goes to the ejector
where power water create the jet velocity to convey the bottom ash to the hydro bin.

Hydro bin is a conical shaped tank
which can separate the ash and the water. Here
two numbers of hydro bin are used. When one
hydro bin is filled with the ash other come into
the service. Each hydro bin can store four days
ash.. When the slurry water comes out from it
and falls on the plate the turbidity is reduced. It
helps the slurry water to settle down the ash at
the bottom. The ash settle down in the bottom
and the water (not pure) is comes out from the
vertical cylindrical centerised strainer. The water from the upper most portion of the hydro
bin means overflow water comes out and goes to the settling tank for more settlement of ash.
In the bottom portion there is a flap gate for ash extraction through this gate the ash is
collected in the truck to dispatch.
` Fly Ash Removal System
For fly ash removal
Macawaber system is used. It
consists of dome valve, solenoid
valve, air seal, Macawaber
compressor, some presser switches,
ash vessel, ash hopper, silo etc.
At first, suppose there is no
ash in the ash vessel, seal air presser
is proper then dome valve is in
closed condition.
After that ash is in hopper
seal air is drained to the atmosphere
through pneumatic switch and quick
exhaust valve so that dome valve can easily open without friction.

Then the five-port solenoid valve is opened &instrument air helps to open the dome
valve. Then ash fall on the ash vessel and dome valve is closed .the pneumatic switch closes
which makes the seal air to the seal of the dome valve .a pressure switch is used to maintain
the pressure sure of the seal.5kg cm2. Then pressure switch gives a signal that the seal air
pressure is ok.
Then solenoid valve opens &the blow valve opens through which Mac air enters for
conveying the ash to the silo .the conveying pressure 1. 5 kg /cm2. There are two pressure
switches near blow valve. One set at a pressure of 4.5 kg /cm2, another switch at 0.39 kg
/cm2.it means that suppose there is a chock age in the dry ash line, then the pressure will
increase .if it is more than 4.5kg/cm2 then blow valve will close the line to be free from choc
age.
The cycle then again starts after 30 sec, known as cycle gap time .
Fly Ash Removal System

UNIT 10
TRANSFORMERS
INTROUCTION
A transformer is a static device that transfers electrical energy from one circuit to another
through inductively conductors—the transformer's coils. A varying current in the first
or primary winding creates a varying magnetic flux in the transformer's core and thus a
varying field through the secondary winding. This varying magnetic field induces a
varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is
called inductive coupling.
If a load is connected to the secondary, current will flow in the secondary winding, and
electrical energy will be transferred from the primary circuit through the transformer to the
load. In an ideal transformer, the induced voltage in the secondary winding (Vs) is in
proportion to the primary voltage (Vp) and is given by the ratio of the number of turns in the
secondary (Ns) to the number of turns in the primary (Np) as follows:
Fig 10:Transformer

CESC HAS VARIOUS TYPES OF TRANS FORMERS WHICH ARE AS FOLLOWS:
STATION TRANSFORMER (ST):
Specification : 16 MVA, 3, 50 Cycles.
VOLTAGE CURRENT
HV 33 KV 279.9A
IV. 6.9 KV 1338.8 A
LV 6.6 KV UNLOADED
Serial No : 24969
Year of Mfg : 1989
Cooling type: ONAN (up to 12 MVA)
ONAF (up to 16 MVA)
Guaranteed temperature rise Oil - 45O
C
Winding – 55O
C
Connection Symbol - Y NY nod
Core and winding weight 24000 Kg
Total Oil 9650 Kg/11000 lt
Total Mass 44400 Kg
Rated C.T. ratio 1338.8/2.4A, 2.6A, 2.7 A, 7.5 VA
No Load Loss 12 KW (Max)
On Load Loss 76 KW
% Impedance HV/IV - 10
#OLTC (On load tap changer) + 8-x x1.25 on – load taps on HV

UNIT TRANSFORMER (UT):
SPECIFICATION:
MAKER CROMPTON GREAVES
MVA 7.5
COOLING ONAN
TEMP RISE: OIL: 45 O
C
Winding: 55 O
C
PHASE: 3
FREQ: 50 HZ
CONN SYMBOL: Dyn11
% impedance 7.5% (at tap No 9)
Tap changer On load + 10%
No of taps - 17
VOLTAGE CURRENT
HV: 10.5 KV 412.4A
LV: 6.6 KV 627.5A
WEIGHTCORE AND WDG 11300 Kg
OIL 4610 Kg
TOTAL 24800 Kg
VOLUME OF OIL 5270 Ltrs
INS LEVEL HVLV – L175 28/L 160 AC 20
YEAR OF MFG 1988.

UNIT AUX TRANSFORMER (UAT):
SPECIFICATION:-
MAKER: THE GENERAL ELECTRICAL C. of INDIA LTD. NAINI
TYPE OF COOLING: ONAN
VECTOR GROUP: DYN11
RATED OF COOLING: ONAN
FREQUENCY: 50 HZ
VOLTAGE CURRENT
HV: 6600 V 87.5 A
LV: 415 V 1333.4 A
INSULATION LEVEL: HV – KVLI 60 - AC 20
LV – KVLI - AC3
LVN - KVLI - AC3
NO OF PHASE: 3
% IMPEDANCE: HV/LV 4.72
TEMPERATURE RISE: TOP OIL 45O
C
AVG WDG 50O
C
YEAR OF MFG 1989
DIAGRAM DRG NO A3 – 2782
CUSTOMER’S REF NO 6285/36, DATED =- 7.10.88.
CORE AND COIL WT 1800 Kg
TANK AND FITTINGS 1355 Kg
MASS OF OIL 845 Kg
TOTAL MASS 4000 Kg
TRANSPORT MASS 3050 Kg
VOLUME OF OIL 970 LTS.

STATION AUX TRANSFORMER (SAT):
Specification
MAKER CROMPTON GREAVES.
KVA 2000
VOLTAGE CURRENT
HV 6600 V 175.0 A
LV 433 V 2667 A
PHASE 3
FREQUENCY 50 HZ
TYPEOF COOLING ONAN
% IMPEDANCE 9.03
CONNECTION SYMBOL DYN11
CORE AND WINDINGS 2600 Kg
WEIGHT OF OIL 1660 Kg
TOTAL WEIGHT 6480 Kg
OIL 1900 LI
DIAGRAM NO T 22 BVF 7083 D.
SL NO 37495 VE
GUARANTEED TEMP RISE OIL – 45O
C
WDG – 55O
C
YEAR OF MANUFACTURE 1989

GENERATOR TRANSFORMER (GT):
SPECIFICATION:
MAKER: CROMPTON GREAVES
MVA: 85
PHASE: 3
FREQ: 50 HZ
CONN SYMBOL: YND11
C
WDG: 50 O
C
% Impedance 12.5
VOLTAGE CURRENT
HV: 35 KV 1402.1
LV: 10.5 KV 4673.3
MASS:
CORE & WDG 59, 0000 Kg
OIL 20480 Kg
TOTAL 106500 Kg.
VOLUME OF OIL: 23400 Ltrs
GUARANTED LOSSES: 12.5%
NO LOAD: 36 KW
LOAD: 250 KW.
BUCHHOLTZ DETAILS: GAS OPERATED RELAY
TYPE OBG 3 E 1
SL NO - MO88111
Tap changer OFF load +5% to –5%
No of taps: 5
Type of cooling ONAN ONAF OFAF
Rating 42 63 85

GENERATORS EXCITATION TRANSFORMER (DRY TYPE):
SPECIFICATION:-
MAKER BHEL (JHANSI)
RATED KVA 600
MODEL CAST RESIN (DRY TYPE)
SL. NO 2004883
RATED CURRENT
(HV) - 33 A
(LV) - 722 A
IMPEDANCE VOLT 6%
TYPE OF COOLING AN
VECTOR GROUP DYN5
TEMPERATURE RISE 90 O
C (OVER 55 O
C)
VOLTAGE VARIATION: CFV,
INSULATION CLASS F
INSULATION LEVEL HV: 75 KVP.
WEIGHT 2000 Kg,
YEAR OF MFG 1988.
OP. PRESSURE 0.50Kg/ Cm2
SL. NO 2797.
TAP NO HV LV
1 11025.0
2 10762.5
3 10500.0 480
4 10237.5
5 9975.0

GENERATOR NEUTRAL GROUNDING TRANSFORMER
SPECIFICATION:-
MAKE: - P.S. ELEC PVT. LTD. MADRAS: 600097
TRANFORMER TO BIS: 3151
TYPE - CAST RESIN
KVA 16
VOLTS (HV) 10.5 KV
VOLTS (LV) 240/120 VOLTS.
CURRENT (HV) 1.52 A
CURRENT (LV) 66.6A/133.3 A
CLASS OF INS - INS – F
TYPE OF COOLING - AN
TEMP. RISE: 70 O
C (ABOVE 50 O
C AMBIENT)
SL. NO. - G156/2
YEAR OF MFG: 1989.
FOR EXCITATON TRANSFORMER:
Current Transformer IS: 2705
Part: III
VA/Class Core 1: 10/ 5 P 10
Ratio 100/1
HV 12 KV ILU 23/75 KV
Frequency 50 HZ.
SL. 205, 206, 213
Type CB2 - 01
Mfg year 1987
Mfd. By. Kappa Electricals, Madras – 32,
India.

COAL HANDLING TRANSFORMERS (CHT):
SPECIFICATION:
MAKE: CROMPTON GREAVES
MVA: 1600
COOLING ONAN
C
WDG: 55 O
C
PHASE: 3
FREQ: 50 HZ
CONN SYMBOL: DYN11
VOLTAGE CURRENT
HV: 6600 V 140.0A
LV: 433 V 2133.3A
WEIGHT
CORE ANDWDG 2020 Kg
OIL 1420 Kg
TOTAL 5200 Kg
VOLUME OF OIL 1620 Ltrs
YEAR OF MFG 1989.
ASH HANDLING TRANSFORMER (AHT):
SPECIFICATION:
MAKE: THE GENERAL ELECTRIC CO OF INDIA LTD.
COOLING: ONAN
KVA: 750
PHASE: 3
FREQ: 50 HZ
VECTOR GROUP: DYN11
VOLTAGE CURRENT
HV: 6600V 65.6A
LV: 433V 1000 A
C
WDG: 55 O
C
INS LEVEL: HV: KV LI60 AC20
LV: KVLI AC3
LVN: KVLI AC3

WEIGHT
CORE AND COIL 1475 Kg
TANK AND FITTINGS 1315 Kg
OIL 760 Kg
TOTAL 3550 Kg
TRANSPORT 2750 Kg
VOLUME OF OIL 875 Litres
ESP TRANSFORMERS:
SPECIFICATION:
KVA: 60
COOLING: ONAN
VOLTS CURRENT
HV 53570 1.12
LV 3373.5 160.6
PHASE 1
FREQ 50 HZ
TEMP RISE of OIL: 0 O
C
WDG:
D.C OUTPUTVOLTAGE: 70 KV.
PEAK 800 MA
WT. OF REACTOR 76 Kg
W.T. OF RECTIFIER 374 Kg (CORE & WDG)
TOTELWT. 1350 Kg
VOLUME OF OIL 440 LI
ELECTRICAL SP. NO 625 159 C
DIAGRAM DRNG NO 246719 50 050

LIGHTING AUXILIARY TRANSFORMER:
SPECIFICATION:-
MAKE: UNIVERSAL MAGNETS
C/26/1 Sarat Chatterjee Road,
HWH – 711104 India
TYPE: DRY: AN NONVENT INDOOR
VECTOR: DYN1 3 Phase
INPUT 415 Δ + 2 ½ % + 5%
OUTPUT 415 V Y 139 A MAX
INS Class C
MAXWinding TEMP 70 O
C
IMPEDANCE 3.8. 3.9 %
Weight: Core + Coil: 580 Kg
TOTAL: 720 Kg
IS 11171 - 1985
SR. NO UM - L 100 - 01
YEAR 1989
CIRCULATING WATER TRANSFORMER:
SPECIFICATION:-
MAKER: GEC
KVA: 1000
COOLING: ONAN
FREQ: 50HZ
PHASE: 3
VOLTAGE CURRENT
HV 6600V 87
LV 433 V 1333.4

% IMPEDNACE : HV/ LV - 4.72
TEMPERATURE : TOP OIL - 45 O
C
AVG WDG - 55 O
C
VECTOR GROUP: DYn11
INS LEVEL : HV - KV L1 60 - AC20
LV - KVL1 - AC3
LVN - KVL1 - AC3.
WEIGHTS:
CORE AND COIL: 1800 Kg
TANK AND FITTING: 1355 Kg
OIL: 845 Kg
TOTAL MASS: 4000 Kg
TRANSPORT MASS: 3050 Kg
VOL OF OIL 970 Ltrs
DIAGRAM DRG NO 43 - 2782
YEAR OF MGF 1988
CUSTOMER REF NO. 6280/36
CT 5389
SR NO. – CWT-1 CT 5389/B - 27040
SR. NO. – CWT – 2 CT 5389/B - 27042
AIR COMPRESSOR TRANSFORMER (ACT):
SPECIFICATION:-
MAKER: CROMPTON GREAVES LTD.
KVA: - 1600
VOLTAGE CURRENT
HV 6600 140.0
LV 433 2133.3

PHASE 3
FREQUENCY 50 HZ
IMPEDANCEVOLT 8.05%
INSULATION LEVEL L 160 AC 20 LIAC 3
TEMPERATURE RISE
OIL 45 O
C
Winding 55 O
C
CORE ANDWINDINGS WEIGHT 2020 Kg
TOTALWEIGHT 5200 Kg
OIL 1620 LI
TYPE OF COOLING ONAN
YEAR OF MANUFACTURE 1989
DIAGRAM NO T 22 BVE 7082 D.
SL NO. 37492 VE
F
Fig Turbine generating system

UNIT 11
CONCLUSION
CESC’s environmental management system focuses on continuous
improvement and upgradation, with state-of-the-art principles and equipment,
setting high targets and reviewing its performances. CESC recognizes its
responsibility towards protecting the ecology, health and safety of the
employees and consumers.
The vocational training has been organized by the CESC limited and has
been undertaken at the Southern Generating Station. The purpose of the
vocational training is to get an industrial exposure in our engineering career.
Students can learn a lot from different books about various subjects such
as operations of a plant, various constituents of a plant, power production,
power distribution etc. but a practical experience helps in better understanding
and enhancement of knowledge in various subjects. I am grateful to CESC
limited for organizing this training.

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