in thermal power plant the turbine losses study

1. SRI VENKATESWARA ENGINEERING COLLEGE
SUYAPET,NALGONDA(DIST)-508213
A MINI-PROJECT presentation on
STUDY AND ANALYSIS OF STEAM TURBINE AND TURBINE LOSSES
IN KTPS
Department of
MECHANICAL ENGINEERING
Project By:-
KRISHAN CHANDRA 10631AO316
MD.SAMEER 10631A0339
KARTHIK KUMAR PRADHAN 10631A0313
M.SRINIVAS REDDY 10631A0346

2. ABSTRACT
 The purpose of present project is to study of steam turbines and turbine losses in
thermal power plant i.e., at 120MW and 110MW.
 It is also used to evaluate the performance of steam turbine.
 A modern thermal power station is a power plant in which the prime mover is
steam driven.
 Water is heated, it turns into steam and spins a steam turbine which drives an
electrical generator.
 Here an attempt is made on various factors that effect on the actual efficiency of
turbine cycle of the plant those are turbine design conditions, turbine losses.
 Turbine cycle efficiency mostly depend on turbine losses, these losses are mainly
two types internal and external losses.
 These losses and analysis of steam turbine discussed in the project.

3. INDEX
S.NO. CONTENTS
1 INTRODUCTION TO KTPS
2 PLANT OVERVIEW
3 RANKINE CYCLE
4 TURBINE THEORY
5 CLASSIFICATION OF STEAM TURBINE
6 CONSTRUCTION OF TURBINE
7 TURBINE COMPONENTS
8 TURBINE LOSSES
9 DATA COLLECTION AT KTPS AND ITS ANALYSIS
10 CALCULATIONS
11 CONCLUSION

4. INTRODUCTION
 It was the first major thermal power station to set up in Andhra Pradesh state
electricity board.
 Kothagudem thermal power station is basically the coal fired thermal power
generation station with total installed capacity of 1720MW.
 The plant has been divided into namely A, B and C stations.
 The actual site of power station is near Paloncha town which is about 12 kms from
the collieries town of Kothagudem in Khammam District.
 The total area of KTPS complex is 5450 acres.
 The entire requirement of coal to the power station is met by M/s Singareni
Collieries Company Ltd.
 from their Rudrampur, Yellandu, Ramachandrapuram, Manuguru mines,
Kothagudem area where proved reserves of about 530 million tonnes of coal
expected to be available

5. PLANT OVERVIEW

6. INSTALLED CAPACITY OF KOTHAGUDEM THERMAL POWER PLANT
STAGE UNIT NO. INSTALLED
CAPACITY(MW)
STATUS
STATION A 1 60 RUNNING
STATION A 2 60 RUNNING
STATION A 3 60 RUNNING
STATION A 4 60 RUNNING
STATION B 5 120 RUNNING
STATION B 6 120 RUNNING

7. INSTALLED CAPACITY OF KOTHAGUDEM THERMAL POWER PLANT
STAGE UNIT NO. INSTALLED
CAPACITY (MW)
STATUS
STATION C 7 120 RUNNING
STATION C 8 120 RUNNING
5th STAGE 9 250 RUNNING
5th STAGE 10 250 RUNNING
6th STAGE 11 500 RUNNING

8. RANKINE CYCLE
 Rankine Cycle is an ideal process. The total steam power plant work based on
Rankine cycle.
 It consist of the following four processes
1. Pump: Isentropic Compression
2. Boiler: Constant Pressure heat addition
3. Turbine: Isentropic Expansion
4. Condenser: Constant Pressure Heat rejection

9. P-V AND T-S DIAGRAMS OF RANKINE CYCLE
 Efficiency of a Rankine cycle is improved by following processes:
• By increasing inlet pressure of Turbine
• By Decreasing Condenser pressure
• By Re-heating
• By Re-generation


10. STEAM TURBINE THEORY
 A turbine is being a form of heat engine which converts thermal energy into
mechanical energy.
 When the working fluid (steam) flows through the turbine, part of enthalpy
energy continuously extracted and converted into useful mechanical work.
 BASIC PRINCIPLES OF STEAM TURBINE:
 Conversion of heat energy into kinetic energy.
 Depends upon the dynamic action of the steam.
 Drop in pressure of steam through some passage resulting.
 To increase in velocity.
 Change in direction of motion gives rise to a change of momentum or
force.
 This is driving force of the prime mover.

11. CLASSIFICATION OF STEAM TURBINE
There are several ways in which the steam turbines may be classified
 According to the action of steam:
a. Impulse Turbine
b. Reaction or Impulse Reaction Turbine
 IMPULSE TURBINE:
 In impulse turbine the steam expands in the nozzles and its pressure does not
alter as it moves over the moving blades.
 As the steam flows through the nozzle its pressure drops from steam chest
pressure (boiler pressure) to condenser pressure.
 The steam leaves the nozzle with very high velocity and strikes the moving blade.
 The moving blades are so shaped which changes the direction of motion of steam.
 Due to this momentum is developed, which exerts a propelling force on the blade
and sets the rotor in rotational motion.

12.  REACTION TURBINE
 In this type of turbine there is gradual drop in pressure and that takes place
continuously over the fixed and moving blades.
 The function of fixed blades (is same as nozzles) that they alter the direction of
steam as well as allow.
 it expand to a larger velocity the steam passes over the moving blades, its kinetic
energy (obtained due to fall in pressure) is absorbed by them.

13. IMPULSE REACTION TURBINE
In an impulse reaction turbine the steam expands in both fixed and moving
blades continuously as the steam passes over them.
 DIFFERENCE BETWEEN IMPULSE AND REACTION TURBINE

14.  According to number of stages
a. Single stage turbine
b. Multi stage turbine
 According to the direction of steam flow:
a. Axial flow turbines
b. Radial flow turbines
 According to the number of cylinders:
a. Single cylinder turbines
b. Double cylinder turbines
c. Three cylinder turbines
d. Four cylinder turbines
 According to the method of governing:
a. Throttle Governing
b. Nozzle Governing
c. By-Pass Governing

15. According to steam conditions at inlet to turbine
a. low pressure turbines :
These turbines use steam at a pressure 1.2 to 2 bar
b. Medium pressure turbines:
These turbines use steam at a pressure up to 40 bar.
c. High pressure turbines:
These turbines use steam at a pressure up to 40 bar.
d. Turbines of very high pressures:
These turbines use steam at pressures of 170 bar and
temperatures of 550ᵒC and higher.
e. Turbines of supercritical pressure:
These turbines use steam at pressures of 225 bar and
above.

16. CONSTRUCTION OF STEAM TURBINES
 A steam turbine has two main parts; they are cylinder (stator) and the rotor. The
cylinder is made of alloy steel or cast steel.
 Housing is usually divided at the horizontal central line. Its valves are bolted
together for easy access.
 The cylinder contains fixed blades and nozzles which direct steam into the moving
blades carried by the rotor.
 A disk and diaphragm pair constitutes a turbine stage. Steam turbines can have
many stages.
 The rotor is a rotating shaft that carries moving blades on the outer edge of either
disk or drum the blades rotate as the rotor revolves.
 The rotor of a large steam turbine consists of high, intermediate and low pressure
sections.

17. TURBINE COMPONENTS
 Static Parts:
 HP (High pressure casing):
 HP casing is made up of Cr-Mo-V alloy casting.
 The HP casing is a double casing type; an inner casing is housed in the
outer casing such that the two are coaxial.

18.  MP (medium pressure) casing
 It is made into two parts. The front part is made up of creep resistance Cr-Mo-v
alloy steel casting.
 The exhaust part is of steel fabricated structure at the outlet side.
 LP Casing:
 LP casing is of double flow type, consists of front, middle and rear parts divided by
vertical parting plates.
 These three parts are fabricated from weld able mild steel.

19.  Bearings
 Two bearings normally support each section of the rotor, with the usage rigid
couplings.
 The three rotor assembly of 110MW turbines is supported on 5 bearings only.
 The thrust come journal bearing being common to HP and MP rotor.

20.  Nozzles
 Steam nozzles are arranged at the inlet of steam turbine casing to increase the
velocity of steam and directing the steam to the moving blades.
 Mostly the fixed blades also work as nozzles in an impulse turbine.
 Nozzles work on the principle of change of pressure energy into kinetic energy.
 That means the steam flow with high pressures passes through the nozzle, losses
its pressure and gains velocity.
 Rotors
 The turbine rotor consists of a row of impulse wheels, assembled with blades.
 One set of stationary and rotor blades is called One Stage of Turbine, number of
stages in a turbine designed to control the speed and load on the turbine.
 Shaft seals are arranged both on turbine and casings to minimize the leak off
steam to atmosphere.
 For large capacity turbines, to control the steam flow and speed & load of the
turbine.
 Number of stages are designed which are accommodated as a combination of HP,
IP & LP turbines.

21.  Blades
 The blades are designed to convert the heat energy of the steam into work energy
(mechanical energy) which gives momentum to the shaft for the rotation.
 The thickness and the length of the blades vary according to the usage either in
impulse turbine or in impulse reaction turbine.
 The blades are also called as fixed blades and moving blades according to usage.

22. TURBINE LOSSES
 Consider briefly some losses which occur in turbines. They can be divided
conveniently into two groups; namely internal and external.
 Internal losses:
 Nozzle friction
 Blade friction
 Disc friction
 Diaphragm gland and blade tip leakage
 Partial admission losses
 Losses due to wetness of steam
 Exhaust velocity losses
 External losses:
 Shaft gland leakage
 Journal and thrust bearings
 Governor and oil pump

23. DATA COLLECTION AT KTPS AND ITS ANLSIS
S.
N
O.
DESCRIPTION UNITS SAMP
LE (1)
SAMP
LE(2)
SAMP
LE(3)
SAMP
LE(4)
SAMP
LE(5)
AVER
AGE
1. Load(p) mw 120 110 120 110 120 120
2. Steam flow ton/hr 360 355 360 355 360 360
3. Feed water flow ton/hr 200 210 200 210 200 200
4. Main steam pressure Bar 128 225 130 126 125 128.3
5. Main steam temperature 0C 535 542 540 539 540 535
6. Temperature of water
before economizer
0C 217 220 225 218 216 219
7. Pressure of water before
economizer
Kg/cm
2
97 100 99 105 98 99.8

24. Data collection at ktps and its analysis
8. Feed water flow
through
economizer
Ton/hr 120 215 217 212 216 214
9. Temperature of
water after
economizer
0C 303 310 312 308 306 308
10. Pressure of water
after economizer
Kg/cm2 93 91 96 99 92 94.2
11. Hot reheat steam
flow
Kg/hr 321 320 321 320 321 321.
7
12. Cooling water
temperature at
inlet of condenser
0C 27 26 28 27 28 27

25. Data collection at ktps and its analysis
13. Feed water pressure
entering in HP-1
Bar 6 5 6 5 6 6
14. Feed water
temperature leaving
in HP-1
0C 206 204 206 205 206 206
15. Feed water pressure
entering in HP-2
Kg/cm2 6 5 5 6 6 6
16. Feed water
temperature leaving
HP-2
0C 293 290 292 290 290 293
17. Condenser vacuum Kg/cm2 -0.92 -0.91 -0.92 -0.91 -0.92 -0.92

26. CALCULATION AND RESULT
Given data,
1. Main steam pressure and temperature (130kg/cm2,5350c)
2. Cold reheat steam pressure and temperature (36kg/cm2,3500c)
3. Hot reheat steam pressure and temperature (32kg/cm2,5350c)
4. MPT exhaust pressure and temperature (2.4kg/cm2,2210c)
5.HP-2 heater extraction pressure and temperature at turbine and heater
(33.6kg/cm2,3460c),
6. HP-1 heater extraction pressure and temperature at turbine and heater
(18.04kg/cm2,4620c)
7. Feed water pressure and temperature entering and leaving HP-1 heater-
(6kg/cm2,1600c,2060c), feed water pressure and temperature entering and leaving
HP-2 heaters-6kg/cm2,2060c,2930c)
8. HP- 1&2 heater drain temperature (1650c, 2110c)
9. Reheat spray flow orifice dp (200tones/hour)
10. Condenser vacuum (-0.92 kg/cm2)
11. Generator load (120MW)

27. TURBINE EFFICIENCY CALCULATION
HP Turbine(120 MW)
1.Main steam pressure = 130Kg/cm2 = 128.3bar
2. Main steam temperature = 535 0c
3. Enthalpy of steam corresponding to 1&2 = 3420KJ/Kg
4. Entropy of steam corresponding to 1&2 = 6.52 KJ/Kg K
5. H.P turbine outlet pressure = 36Kg/Cm2 = 35.5 bar
6. H.P turbine outlet temperature = 348 0c
7. Enthalpy of steam corresponding to 5&6 = 3060KJ/Kg
8. Enthalpy of steam corresponding to 5&4 = 3416.2KJ/Kg
9. Efficiency of H.P turbine = n H.P.T = ( h3 - h7 )
( h3 - h8 )
= 3430 - 3060
3430 - 3416.2
= 97.3%
The efficiency of the H.P turbine = nH.P.T = 97.3%

28. IP TUBINE(120MW)
1. Hot reheat pressure = 31.63 Kg/cm2 = 31.22bar
2.Hot reheat temperature = 535 0c
3. Enthalpy of steam corresponding to 1&2 = 3539 KJ/Kg
4.Entropy of steam corresponding to 1&2 = 7.24KJ/Kg K
5. Steam pressure at L.P turbine = 2.43 KJ/Cm2 = 2.39bar
6.Steam temperature at L.P turbine = 215 0c
7. Enthalpy of steam corresponding to5&6 = 2900Kj/Kg
8. Enthalpy of steam corresponding to 5&4 = 2820 KJ/Kg
9. Efficiency of H.P turbine = nP.T = ( h3 - h7 )
( h3 - h8 )
= (3539-2900)
(3539-2820)
The efficiency of the I.P turbine = nH.P.T = 88.0%

29. LP TURBINE(120MW)
1. Steam pressure before L.P turbine = 31.63 Kg/Cm2 = 31.22 bar
2. Steam temperature before L.P turbine = 535 0c
3.Enthalpy of steam corresponding to 1&2 = 2900 KJ/Kg
4. Entropy of steam corresponding to 1& 2 = 7.24KJ/kg K
5. Steam pressure at L.P turbine exhaust = 2.43 Kg/Cm2 = 2.39bar
6. Steam temperature at L.P turbine exhaust = 221 0c
7. Enthalpy of steam corresponding to 5&6 = 2581 KJ/Kg
8.Enthalpy of steam corresponding to 5&4 =2418.8 kj/kg
9. Efficiency of L.P turbine = nP.T = ( h3 - h7)
( h3 - h8)
= (2900-2581)
(2900-2418.8)
= 66.3%
TURBINE EFFICIENCY= HP+IP+LP/3
= 97.3+88.0+66.3/3
=83.9%

30. TCHR= Turbine Cycle Heat Rate
mLS : Main steam flow kg/hr
hLS : Enthalpy of steam entering Hp turbine
hfw : Enthalpy of feed water at HP Heater out let k.cal/kg
mhrh : Hot reheat steam flow in kg/hr
hhrh : Enthalpy of steam entering MP turbine k.cal/kg
hcrh : Enthalpy of steam leaving HP turbine (cold reheat )k Cal/kg
MSWPR : Mass flow rate of spray water
Pgen : Electrical power output at the generator terminal in KW
mLS : 360x103 kg/hr
hLS : 819.8k.cal/kg
hfw : 164.2k.cal/kg
mhrh : 321.705kg/hr
hhrh : 844.1k.cal/kg
hcrh : 741.2K.cal/kg
mswpr : 2x103 kg/hr
Pgen : 120x 103Kw

31. TCHR = mLS ( hLS - hFW ) + mhrh ( hhrh - hcrh ) + mSWPR ( hcrh – hfw)
Pgen
=360x1000(819.8-164.2)+321.70x1000(844.1- 741.2)+2x1000(741.2-
164.2)/120x103
= 2252.25K.Cal/Kwh
Thermal efficiency=heat converted into useful work/TCHR
= 860x100
2252.25
nthermal= 38.1%

32. LOSSES CALCULATION
 Turbine entering enthalpy=3420kj/kg
 turbine exhaust temperature=2210c
 turbine exhaust pressure=2.39 bar
from steam table
 enthalpy of steam turbine at exhaust =2969.6kj/kg
 Turbine losses in enthalpy=Enthalpy of turbine at entering -enthalpy of turbine at
exhaust
=3420-2969.6
=450.4kj/kg
According to present=16.1%

33. Internal losses
S.NO TYES OF LOSSES IN %
CALCULATION
RESULT IN
KJ/KG
1. Nozzle losses(10%) 450.4x10/100 45.04kj/kg
2. Blade friction losses(3%) 450.4x3/100 13.51kj/kg
3. Disc friction losses(0.88%) 450.4x0.88/100 3.96kj/kg
4. Diaphragm gland and blade
tip leakage(0.1%)
450.4x0.1/100 0.45kj/kg
5. Partial admission
losses(0.88%)
450.4x0.88/100 3.96kj/kg
6. Losses due to wetness of
steam(0.55%)
450.4x0.55/100 2.47kj/kg
7. Exhaust velocity
losses(0.1%)
450.4x0.1/100 0.45kj/kg

34. External losses
RESULT:
 STEAM TURBINE EFFICIENCY= 83.9%
 THERMAL EFFICIENCY= 38.1%
 STEAM TURBINE LOSSES=16.1%
1. Shaft gland leakage(0.1%) 450.4x0.1/100 0.45kj/kg
2. Journal and thrust bearing
losses(0.55%)
450.4x0.55/100 2.47kj/kg
3. Governor and oil
pump(0.1%)
450.4x0.1/100 0.45kj/kg

35. CONCLUSION
 The steam turbine itself is a device to convert the heat in steam to mechanical
power.
 The difference between the heat of steam per unit mass at the inlet to the turbine
and heat of steam per unit mass at the outlet.
 turbine represents the heat which is converted to mechanical power.
 Therefore, the more the conversion of heat per pound or kilogram of steam to
mechanical power gives more efficiency.
 Hence the steam turbine place a vital role in the thermal power plant in achieving
a greater efficiency.