study and analysis of steam turbine and turbine losses

SRI VENKATESWARA ENGINEERING COLLEGESUYAPET,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

ABSTRACT

The purpose of present project is to study of steam turbines and turbine losses inthermal 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 issteam driven.

Water is heated, it turns into steam and spins a steam turbine which drives anelectrical generator.

Here an attempt is made on various factors that effect on the actual efficiency ofturbine cycle of the plant those are turbine design conditions, turbine losses.

Turbine cycle efficiency mostly depend on turbine losses, these losses are mainlytwo types internal and external losses.

These losses and analysis of steam turbine discussed in the project.

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

INTRODUCTION

It was the first major thermal power station to set up in Andhra Pradesh stateelectricity board.

Kothagudem thermal power station is basically the coal fired thermal powergeneration 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 fromthe 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 SingareniCollieries Company Ltd.

from their Rudrampur, Yellandu, Ramachandrapuram, Manuguru mines,Kothagudem area where proved reserves of about 530 million tonnes of coalexpected to be available

PLANT OVERVIEW

INSTALLED CAPACITY OF KOTHAGUDEM THERMAL POWER PLANT

STAGE UNIT NO. INSTALLED CAPACITY(MW)

STATUS

STATION A 1 60 RUNNING




STATION B 5 120 RUNNING

STATION B 6 120 RUNNING

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



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 Compression2. Boiler: Constant Pressure heat addition 3. Turbine: Isentropic Expansion 4. Condenser: Constant Pressure Heat rejection

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

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.

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 notalter as it moves over the moving blades.

As the steam flows through the nozzle its pressure drops from steam chestpressure (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 bladeand sets the rotor in rotational motion.

REACTION TURBINE

In this type of turbine there is gradual drop in pressure and that takes placecontinuously over the fixed and moving blades.

The function of fixed blades (is same as nozzles) that they alter the direction ofsteam as well as allow.

it expand to a larger velocity the steam passes over the moving blades, its kineticenergy (obtained due to fall in pressure) is absorbed by them.

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

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

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.

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.

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.

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.

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.

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.

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 inimpulse turbine or in impulse reaction turbine.

The blades are also called as fixed blades and moving blades according to usage.

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

DATA COLLECTION AT KTPS AND ITS ANLSIS

S.NO.

DESCRIPTION UNITS SAMPLE (1)

SAMPLE(2)

SAMPLE(3)

SAMPLE(4)

SAMPLE(5)

AVERAGE

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/cm2

97 100 99 105 98 99.8

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

Data collection at ktps and its analysis

13. Feed water pressure entering in HP-1

Bar 6 5 6 5 6 6

14. Feed watertemperature 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

CALCULATION AND RESULTGiven 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)

TURBINE EFFICIENCY CALCULATIONHP 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%

IP TUBINE(120MW)

1. Hot reheat pressure = 31.63 Kg/cm2 = 31.22bar2.Hot reheat temperature = 535 0c3. Enthalpy of steam corresponding to 1&2 = 3539 KJ/Kg4.Entropy of steam corresponding to 1&2 = 7.24KJ/Kg K5. Steam pressure at L.P turbine = 2.43 KJ/Cm2 = 2.39bar6.Steam temperature at L.P turbine = 215 0c7. Enthalpy of steam corresponding to5&6 = 2900Kj/Kg8. Enthalpy of steam corresponding to 5&4 = 2820 KJ/Kg9. 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%

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 0c3.Enthalpy of steam corresponding to 1&2 = 2900 KJ/Kg 4. Entropy of steam corresponding to 1& 2 = 7.24KJ/kg K5. Steam pressure at L.P turbine exhaust = 2.43 Kg/Cm2 = 2.39bar6. Steam temperature at L.P turbine exhaust = 221 0c7. Enthalpy of steam corresponding to 5&6 = 2581 KJ/Kg8.Enthalpy of steam corresponding to 5&4 =2418.8 kj/kg9. 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%

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

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%

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%

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

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

CONCLUSION

The steam turbine itself is a device to convert the heat in steam to mechanicalpower.

The difference between the heat of steam per unit mass at the inlet to the turbineand 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 tomechanical power gives more efficiency.

Hence the steam turbine place a vital role in the thermal power plant in achievinga greater efficiency.

study and analysis of steam turbine and turbine losses

Engineering