GAS TURBINE POWER STATION

B.Tech. Industrial Training

Report

In

Mechanical Engineering

By

Muneer Ahmed (ME-11-80)

Department of Mechanical Engineering

Al-Falah School of Engineering & Technology, Dhauj

Faridabad, Haryana (India)

May 2015

GAS TURBINE POWER STATION

B.Tech. Industrial Training

Report

Submitted In partial fulfillment of the

Requirement for the award of the degree

of

Bachelor of Technology

In

Mechanical Engineering

By

Muneer Ahmed (ME-11-80)

Under the Guidance of

Mr. Hasan Zakir Jafri

Department of Mechanical Engineering

Al-Falah School of Engineering. & Technology, Dhauj

Faridabad, Haryana (India)

May 2015

CERTIFICATE

I hereby certify that the work which is being presented in the B.Tech. Project Entitled “GAS

TURBINE POWER STATION” in partial fulfillment of the requirement for the award of the

Bachelor of Technology and submitted to the Department of Mechanical Engineering is an

authentic record of our own work carried out during the period from January’ 2015 to May’ 2015

under the guidance of Mr. Hasan Zakir Jafri (Assistant Prof.) in the Department of Mechanical

Engineering.

The matter presented in this report has not been submitted by me for the award of any

other degree elsewhere.

Muneer Ahmed (ME-11-80)

Date: 12-05-2015

Hasan Zakir Jafri Prof. Mohd. Parvez

(Assistant Professor) Head

Guide ME & MAE

Internal Examiner External Examiner

i

Declaration

I declare that this written submission represents my ideas in my own words and where others’

ideas or word have been included, I have adequately cited and referenced the original sources. I

also declare that I have adhered to all principles of academic honesty and integrity and have not

misrepresented or fabricated or falsified any idea/data/fact/source in my submission. I understand

that my violation of the above will be cause for disciplinary action by the institute and can also

evoke penal action from the sources which have thus not been properly cited or from whom

proper submission has not been taken when needed.

Muneer Ahmed(ME/11/80)

Department of Mechanical Engineering

Date: 12-05-2015

ii

List of Figures

Figure No. Name Page

1.1 Typical Gas Turbine Power Station 1

1.2 Components of Gas Turbine Power Station 4

1.3 Components of Gas Turbine 5

1.4 Open Cycle Gas Turbine 6

1.5 Close Cycle Gas Turbine 7

1.6 Schematic Arrangement of Open Cycle Gas Turbine Power

Station 8

1.7 Simple Cycle Diagram 10

1.8 Close Cycle Diagram 11

1.9 Combine Cycle Power Plant 12

2.1 Typical Close Cycle Power Plant Sketch 13

2.2 Close Cycle Power Plant Diagram 15

2.3 P-V Chart of Dual Cycle 19

2.4 Working of a Combine Cycle power Plant 20

2.5 Combine Cycle Plant Design 21

2.6 Combine Cycle Heat Balance 22

3.1 Gas Turbine 26

3.2 Gas Turbine Components 27

3.3 P-V and T-S Chart of Gas Turbine 29

3.3 Ideal Gas Turbine Cycle 31

4.1 Combustor Diagram 37

4.2 Combustor arrangement in a Gas Turbine 37

4.3 Compressor in Gas turbine 39

4.4 Various Compressors and their Components 40

5.1 Components Of Heat Recovery Steam Generator 44

5.2 Actual Picture of HRSG in Gas Turbine Power Station 38

5.3 Flow Diagram Of Gas Turbine Power Station 44

6.1 Transformer Installed in Gas Turbine Power Station 45

6.2 Types of Transformers 46

6.3 Actual Cut in Section of Generator 47

7.1 Water Treatment Plant 53

7.2 Anion and Cation Water Filters 54

7.3 Switch Yard Working 55

7.4 Isolators 56

7.5 Circuit Breakers 56

7.6 Insulators 57

7.7 Bus Couplers 57

iv

List of Tables

Table No. Name Page

1.1 Specifications of Power Plants Under I.P.G.C.L. 3

3.6 Comparison Between Heavy Duty and Aero-Derivative

Gas Turbine

34

6.4 Altitude Correction Graph

49

6.5 Humidity Correction Graph

50

v

Acknowledgement

I wish to express my sincere thanks to Mr. Piyush Gupta,Manager (Tech.) of Gas Turbine Power

Station,Indraprastha Power Generation Co. Ltd, for providing me with all the necessary facilities

for the thesis.

I place on record, my sincere thank Mr. Chetan Pathania(Supervisor of my internship), for the

continous encouragement and their supervision throughout this dissertation.

I am also grateful to Hasan Zakir Jafri, assistant professor, in the Department of Mechanical

Engineering. I am extremely thankful and indebted to him for sharing expertise, and sincere and

valuable guidance and encouragement extended to me.

I am also grateful to my batch mates of engineering and Internship fellows Ammar Faris bearing

Roll no. MA/12/09D Mechanical and Automation (8TH SEM.) and Syeed Uz Zafar Khan bearing

Roll No. ME/11/148 Mechanical Engineering (8th SEM.). of A.F.U.

I take this opportunity to express gratitude to all of the Department faculty members of Al-Falah

University for their help and support.

I also thank my parents for the unceasin encouragement, support and attention.

I also place on record, my sense of gratitude to one and all, who directly or indirectly, have lend

their hand in this dissertation.

vi

Table of contents

Certificate i

Declaration ii

List of figure iii-iv

List of Tables v

Acknowledgement vi

Table of contents vii-x

Abstract xi

Chapter 1: Introduction 1-12

1.0 Gas Turbine Power Plant 1

1.1 Brief Profile of the Company 2

1.2 Specifications of Power Plants under I.P.G.C.L. 3

1.3 Components of Gas Turbine 5

1.31 How does a Gas Turbine Works 5

1.4 Types of Gas Turbine Power Stations 6

1.5 Open Cycle Gas Turbine Power Station 7

1.6 Close Cycle Gas Turbine Power Station 9

1.7 Fuels for Gas Turbine Power Stations 11

Chapter 2: Combine Cycle Power Plant 11-25

2.0 Introduction to Combine Cycle Power Plant 13

2.01 Mechanism 14

2.02 Working Principle of CCGT 14

vii

2.03 Air Inlet 15

2.04 Turbine Cycle 16

2.05 Heat Recovery Steam Generator 16

2.2 Typical Size and Configuration of CCGT Plant 17

2.21 Efficiency of CCGT Plant 17

2.22 Fuels for CCPT Plant 18

2.23 Emission Control 18

2.3 Combining the Brayton and Rankine Cycle 18

2.31 Major Combined Cycle Pant Equipment 20

2.4 Other Specifications of Combined Cycles 23

2.5 Results and Conclusions 24

Chapter 3: Gas Turbine 26-36

3.0 Introduction 26

3.1 History of Gas Turbines 27

3.2 Classifications of Gas Turbines 28

3.3 Working Cycle 29

3.31 Calculating Efficiency Using Euler’s Equation 30

3.32 Principle of Operation 30

3.33 Ideal Gas Turbine Cycle 31

3.4 Accessories 33

3.5 Results 35

Chapter 4: Combustor and Compressor 37-41

4.0 Introduction 37

viii

4.01 Gas Turbine Combustor Arrangement 38

4.1 Compressor 39

4.11 Introduction 39

4.3 Result and Conclusions 41

Chapter 5: Heat Recovery Steam Generator 42-44

5.0 Introduction 42

5.1 Components of H.R.S.G. 42

5.2 Conclusion 44

Chapter 6: Transformer and Generators 45-52

6.0 Introduction to Transformers 45

6.2 Types of Transformers 46

6.3 Introduction to Generators 47

6.4 Gas Turbine Generator Performance 48

6.41 Altitude Correction 49

6.42 Humidity Correction 50

6.5 Results and Conclusions 51

Chapter 7: Other Components of Gas Turbine Power Station 53-57

7.0 Water Treatment Plant 53

7.01 Phases of Water Treatment 54

7.1 Switch Yard 55

7.11 Various Equipment Installed in Switch Yard 56

ix

Chapter 8: Results and Conclusions 58-59

8.0 Positive Points of Gas Turbine Power Station 58

8.1 Negative Points of Gas Turbine Power Station 59

8.2 Discussions 59

Chapter 9: Summary and Conclusions 60-62

9.0 Summary 60

9.1 Conclusions 61

References

Appendix

x

Abstract

I.P.G.C.L. Gas Turbine Power Station is located at Delhi.

IPGCL Gas Turbine Power Station has an installed capacity of 270 MW. The power plant have

nine power generating units.

Six Gas Turbine Units of 30 MW each were commissioned in 1985-86 to meet the electricity

demand in peak hours and were operating on liquid fuel. In 1990 the Gas Turbines were

converted to operate on natural gas. Later due to growing power demand the station was

converted into combined cycle gas turbine Power Station by commissioning 3x34 MW Waste

Heat Recovery Units, in 1995-96. The total capacity of this Station is 282 MW. The gas supply

has been tied up with GAIL through HBJ Pipeline. The APM gas allocation was not sufficient

for maximum generation from the power station. Subsequently with the availability of

Regassified -LNG an agreement was made with GAIL in Jan. 2004 for supply of R-LNG so that

optimum generation could be achieved. The performance of the station has improved from 49 %

in 2002-03 to 70.76 % in 2005-06.

Gas Turbine Power Station (GTPS) with a total capacity of 282 MW having six gas turbines of

30 MW each using CNG/LNG as fuel and three steam turbines of 34 MW each.

xi

Chapter 1

Introduction

1.0 Gas Turbine Power Plant

The simple gas turbine power plant mainly consists of a gas turbine coupled to a rotary type air

compressor and a combustor or combustion chamber which is placed between the compressor

and turbine in the fuel circuit. Auxillaries, such as cooling fan, water pumps, etc. and the

generator itself, are also driven by the turbine. Other auxillaries are starting device, lubrication

system, duct system, etc. A modified plant may have in addition to the above, an inter-cooler, a

regenerator and a reheater.

Figure -1.1 Typical Gas Turbine Power Station

1.1 Brief Profile of the company

• Under IPGCL i.e. Indraprastha Power Generation Company Limited,3 Power Stations are

in operation.They are as follows :

1)I.P STATION

2)RAJGHAT POWER HOUSE

3)GAS TURBINE POWER STATION (GTPS)

• Under PPCL i.e. Pragati Power Cooperation Limited, one Power Station is in operation

and it is:

PRAGATI POWER STATION

MISSION OF THE COMPANY

• To make Delhi-Power Surplus

• To maximize generation from available capacity

• To plan and implement new generation capacity in Delhi

• To set ever so high standards of environment Protection

• To develop competent human resources for managing the company with good standards.

2

1.2 Specifications of Power Stations under I.P.G.C.L.

STATIONS I.P STATION RAJGHAT

POWER

STATION

GTPS PRAGATI POWER STATION

Station Capacity

(MW)

247.5 135 282 330

Units 3*62.5 (GT) +

60 (ST)

2*67.5 (GT) 6*30 (GT) +

3*34 (WHRU)

2*104 (GT) + 1*122 (WHRU)

Year of

Commissioning

1967-71 1989-90 1986 & 1996 2002-2003

Coal Field/Gas NCL,BINA NCL,BINA GAIL HBJ

Pipeline

GAIL HBJ Pipeline

Water Sources River Yamuna River Yamuna River Yamuna Treated water from Sen

Nursing Home & Delhi Gate

Sewage Treatment Plants

Beneficiary

Areas

VIP-South &

Central Delhi

Central &

North Delhi

NDMC-

VIP,DMRC

NDMC,South Delhi

Table 1.1 Overview Of Several Power Plants Of I.P.G.C.L.

3

How does Gas Turbine works?

Gas turbine functions in the same way as the Compressed Ignition Engine. It sucks in air

from the atmosphere, compresses it.

The fuel is injected and ignited. The gases expand doing work and finally exhausts

outside.

The only difference is instead of the reciprocating motion, gas turbine uses a rotary

motion throughout.

Figure -1.2 Components of G.T.P.S.

4

1.3 Components of Gas Turbine

The three main sections of the Gas Turbine

1. Compressor

2. Combuster

3. Turbine

Figure -1.3 Components of Gas Turbine

5

1.4 TYPES OF GAS TURBINE POWER PLANTS

The gas turbine power plants can be classified mainly into two categories. These are :open cycle

gas turbine power plant and closed cycle gas turbine power plant.

Open Cycle Gas Turbine Power Plant- In this type of plant the atmospheric air is charged into

the combustor through a compressor and the exhaust of the turbine also discharge to the

atmosphere.

Specifications of open cycle gas turbine

Fresh air is drawn into the compressor from atmosphere.

Heat is added by combustion of fuel.

Exhaust from turbine is released in atmosphere.

Arrangement of continuous replacement of working medium is required.

Figure -1.4 Open cycle Gas Turbine

Closed Cycle Gas Turbine Power Plant- In this type of power plant, the mass of air is constant

or another suitable gas used as working medium, circulates through the cycle over and over

again.

In this , cycle is closed and exhaust is not open to atmosphere.

6

In this there is continuously supply of same working gas.

Higher density gases like hydrogen or carbon dioxide is used.

So we get higher efficiency then open cycle GT.

1.5 OPEN CYCLE GAS TURBINE POWER PLANT AND ITS

CHARACTERISTICS

Figure 1.6 The schematic arrangement of a simple open cycle gas turbine power plant

In the process shown the cycles are :

2-3: Isentropic compression

3-4: Heat addition at constant pressure

4-1: Isentropic expansion

1-2: Heat rejection at constant pressure

7

The ideal thermal efficiency for the cycle,ç t, is given by, Heat supplied - Heat

rejected/Heat supplied

where, r is the compression ratio=V2/V3and k is the ratio of specific heat of the gas.

In actual operation the processes along 2-3 and 4-1 are never isentropic and the degree of

irreversibility of these processes and the mechanical efficiencies of the machine components

greatly reduce the ideal value of thermal efficiencies of the cycle. If the air entering the

combustor is preheated by the heat of exhaust gases escaping from the turbine, some heat can be

recovered resulting into an increase in the efficiency of the cycle improved. Such heating of

combustion air is known as regeneration and the heat exchanger transferring heat from gas to air

is called regenerator.

Since most of the output of turbine is consumed by the compressor, the actual efficiency of the

cycle greatly depends upon an efficient working of the compressor. To attain higher compression

ratios, it is necessary to use multi-stage compression with inter-cooling. In actual practice, all

these modifications, viz. regeneration, reheating and inter-cooling are combined in a simple

modified cycle and a substantial gain in the overall plant efficiency is attained.

Simple Cycle

Figure 1.7 Simple Cycle Diagram

8

Simple Cycle Power Plant

1.6 CLOSED CYCLE GAS TURBINE POWER PLANTAND ITS

CHARACTERISTICS

In the closed cycle, quantity of air is constant, or another suitable gas used as working medium,

circulates through the cycle over and over again. Combustion products do not come in contact

with the A development in the basic gas turbine cycle is the use of the closed cycle which

permits a great deal of flexibility in the use of fuels. Moreover, working medium of the plant

could be any suitable substance other than air which would give higher efficiency. An

arrangement of closed gas turbine cycle is shown in Figure in next slide. In this cycle, working

fluid is compressed through the requisite pressure ratio in the compressor, and fed into the

heater, where it is heated up to the temperature of turbine itself.

working fluid and, thus, remain closed.

9

Arrangement of Closed Cycle Gas Turbine Plant

Figure -1.8 Close Cycle Diagram

The fluid is then expanded in the turbine and the exhaust is cooled to the original temperature in

the pre-cooler. It then re-enter the compressor to begin the next cycle. Thus, the same working

fluid circulates through the working parts of the system. The heater burns any suitable fuel and

provides the heat for heating the working fluid. In fact, this combustor is akin to an ordinary

boiler furnace, working at the atmosphere pressure and discharging the gaseous products to the

atmosphere. There is, thus, a great deal of flexibility in respect of furnace design and use of fuel,

allowing low cost fuel to be used

Another advantages in use of closed cycle is the choice of selecting a convenient pressure range,

once the pressure ratio has been selected. The volume of the air or the working fluid in the cycle

depends upon the pressure range which, in turn, affects the sizes of the air heater, compressor,

turbine, etc. In a closed cycle, there is no restriction to keep the pressure low and this could be

kept at any suitable value say 7.03 kg/cm2(68.9 N/cm ) abs.

The pre-cooler in a closed cycle plant is an important equipment and corresponds to the

condenser of a steam plant. However, unlike the condenser, cooling water in the pre-cooler could

be heated to a fairly high temperature depending upon temperature of exit gas from the turbine,

and then used elsewhere in the plant. The design of pre-cooler is commonly of the shell and tube

type, and water is the coolant commonly used. The air heater of the closed cycle corresponds to

the water heaters of the steam plant, but with one important difference that it has very small heat

storage capacity .

10

Combined Cycle Power Plant

Figure – 1.9 Combine Cycle Power Plant.

1.7 FUEL FOR GAS TURBNE POWER PLANTS

Natural gas is the ideal fuel for gas turbines, but this is not available everywhere. Blast furnace

and producer gas may also be used for these plants. However, liquid fuels of petroleum origin,

such as, distillate oils or residual oils are most commonly used for gas turbine power plants. The

essential qualities of these fuels include proper volatility, viscosity and calorific value. At the

same time, the fuel should be free from any content of moisture and suspended impurities that

may clog the small passages of the nozzles and damage valves and plungers of the fuel pump.

However, liquid fuels of petroleum origin, such distillate oils or residual oils are most commonly

used for gas turbine plants. Residual oils burns with less ease than distillate oils and the heaters

are often used to start the unit from cold, after which the residual oils are red into the combustor.

Pre-heating of residual oils may be necessary in cold climates. Use of solid fuel, such as coal in

pulverized form in gas turbines presents several difficulties, most of which have been only

partially overcome.

11

Figure 1.10 Working of Gas Power Plant

12

Chapter 2

Combine Cycle Power Plant

2.0 Introduction Of Combine Cycle Power Plant

The Combined Cycle Power Plant or combined cycle gas turbine, a gas turbine generator

generates electricity and waste heat is used to make steam to generate additional electricity via a

steam turbine. The gas turbine is one of the most efficient one for the conversion of gas fuels to

mechanical power or electricity. The use of distillate liquid fuels, usually diesel, is also common

as alternate fuels.

More recently, as simple cycle efficiencies have improved and as natural gas prices have fallen,

gas turbines have been more widely adopted for base load power generation, especially in

combined cycle mode, where waste heat is recovered in waste heat boilers, and the steam used

to produce additional electricity.

This system is known as a Combined Cycle. The basic principle of the Combined Cycle is

simple: burning gas in a gas turbine (GT) produces not only power – which can be converted to

electric power by a coupled generator – but also fairly hot exhaust gases.

Routing these gases through a water-cooled heat exchanger produces steam, which can be

turned into electric power with a coupled steam turbine and generator.

Figure- 2.1 Typical Combine Cycle Power Plant Sketch

13

This type of power plant is being installed in increasing numbers round the world where there is

access to substantial quantities of natural gas.

A Combined Cycle Power Plant produces high power outputs at high efficiencies (up to 55%)

and with low emissions. In a Conventional power plant we are getting 33% electricity only and

remaining 67% as waste.

By using combined cycle power plant we are getting 68% electricity.

It is also possible to use the steam from the boiler for heating purposes so such power plants

can operate to deliver electricity alone or in combined heat and power (CHP) mode.

2.01 Mechanism

Combined cycle power plant as in name suggests, it combines existing gas and steam

technologies into one unit, yielding significant improvements in thermal efficiency over

conventional steam plant. In a CCGT plant the thermal efficiency is extended to approximately

50-60 per cent, by piping the exhaust gas from the gas turbine into a heat recovery steam

generator.

However the heat recovered in this process is sufficient to drive a steam turbine with an

electrical output of approximately 50 per cent of the gas turbine generator.

The gas turbine and steam turbine are coupled to a single generator. For startup, or ‘open cycle‘

operation of the gas turbine alone, the steam turbine can be disconnected using a hydraulic

clutch. In terms of overall investment a single-shaft system is typically about 5 per cent lower in

cost, with its operating simplicity typically leading to higher reliability.

2.02 Working principle of CCTG plant

First step is the same as the simple cycle gas turbine plant. An open circuit gas turbine has a

compressor, a combustor and a turbine. For this type of cycle the input temperature to turbine is

very high. The output temperature of flue gases is also very high.

This is therefore high enough to provide heat for a second cycle which uses steam as the

working medium i.e. thermal power station.

14

Figure -2.2 Combine Cycle Plant Diagram

2.03 Air Inlet

This air is drawn though the large air inlet section where it is cleaned cooled and controlled.

Heavy-duty gas turbines are able to operate successfully in a wide variety of climates and

environments due to inlet air filtration systems that are specifically designed to suit the plant

location.

Under normal conditions the inlet system has the capability to process the air by removing

contaminants to levels below those that are harmful to the compressor and turbine.

In general the incoming air has various contaminants. They are:

In Gaseous state contaminants are:

• Ammonia

• Chlorine

• Hydrocarbon gases

• Sulfur in the form of H2S, SO2

• Discharge from oil cooler vents

In Liquid state contaminants are:

• Chloride salts dissolved in water (sodium, potassium)

• Nitrates

15

• Sulfates

• Hydrocarbons

In Solid State contaminants are:

• Sand, alumina and silica

• Rust

• Road dust, alumina and silica

• Calcium sulfate

• Ammonia compounds from fertilizer and animal feed operations

• Vegetation, airborne seeds

Corrosive Agents:

Chlorides, nitrates and sulfates can deposit on compressor blades And may result in stress

corrosion attack and/or cause corrosion Pitting. Sodium and potassium are alkali metals that can

combine with Sulfur to form a highly corrosive agent and that will attack portions of the hot gas

path. The contaminants are removed by passing through various types of filters which are

present on the way.

Gas phase contaminants such as ammonia or sulfur cannot be removed by filtration. Special

methods are involved for this purpose.

2.04 Turbine Cycle

The air which is purified then compressed and mixed with natural gas and ignited, which causes

it to expand. The pressure created from the expansion spins the turbine blades, which are

attached to a shaft and a generator, creating electricity.

In second step the heat of the gas turbine’s exhaust is used to generate steam by passing it

through a heat recovery steam generator (HRSG) with a live steam temperature between 420

and 580 °C.

2.05 Heat Recovery Steam Generator

In Heat Recovery Steam Generator highly purified water flows in tubes and the hot gases passes

a around that and thus producing steam .The steam then rotates the steam turbine and coupled

generator to produce Electricity. The hot gases leave the HRSG at around 140 degrees

centigrade and are discharged into the atmosphere.

The steam condensing and water system is the same as in the steam power plant.

16

2.2 Typical Size and Configuration of CCGT Plants

The combined-cycle system includes single-shaft and multi-shaft configurations. The single-

shaft system consists of one gas turbine, one steam turbine, one generator and one Heat

Recovery Steam Generator (HRSG), with the gas turbine and steam turbine coupled to the

single generator on a single shaft.

Multi-shaft systems have one or more gas turbine-generators and HRSGs that supply steam

through a common header to a separate single steam turbine-generator. In terms of overall

investment a multi-shaft system is about 5% higher in costs.

The primary disadvantage of multiple stage combined cycle power plant is that the number of

steam turbines, condensers and condensate systems-and perhaps the cooling towers and

circulating water systems increases to match the number of gas turbines.

2.21 Efficency of CCGT Plant

Roughly the steam turbine cycle produces one third of the power and gas turbine cycle

produces two thirds of the power output of the CCPP. By combining both gas and steam

cycles, high input temperatures and low output temperatures can be achieved. The efficiency of

the cycles adds, because they are powered by the same fuel source.

To increase the power system efficiency, it is necessary to optimize the HRSG, which serves as

the critical link between the gas turbine cycle and the steam turbine cycle with the objective of

increasing the steam turbine output. HRSG performance has a large impact on the overall

performance of the combined cycle power plant.

The electric efficiency of a combined cycle power station may be as high as 58 percent when

operating new and at continuous output which are ideal conditions. As with single cycle thermal

units, combined cycle units may also deliver low temperature heat energy for industrial

processes, district heating and other uses. This is called cogeneration and such power plants are

often referred to as a Combined Heat and Power (CHP) plant.

The efficiency of CCPT is increased by Supplementary Firing and Blade Cooling.

Supplementary firing is arranged at HRSG and in gas turbine a part of the compressed air flow

bypasses and is used to cool the turbine blades. It is necessary to use part of the exhaust energy

through gas to gas recuperation. Recuperation can further increase the plant efficiency,

especially when gas turbine is operated under partial load.

17

2.22 Fuels for CCPT Plants

The turbines used in Combined Cycle Plants are commonly fuelled with natural gas and it is

more versatile than coal or oil and can be used in 90% of energy applications. Combined cycle

plants are usually powered by natural gas, although fuel oil, synthesis gas or other fuels can be

used.

2.23 Emissions Control

Selective Catalytic Reduction (SCR):

To control the emissions in the exhaust gas so that it remains within permitted levels as it enters

the atmosphere, the exhaust gas passes though two catalysts located in the HRSG.

One catalyst controls Carbon Monoxide (CO) emissions and the other catalyst controls Oxides of

Nitrogen, (NOx) emissions. Aqueous Ammonia – In addition to the SCR, Aqueous Ammonia (a

mixture of 22% ammonia and 78% water) is injected into system to even further reduce levels of

NOx.

2.3 Combining the Brayton and Rankine Cycles

In CCPP ,a successful common combination is the Brayton cycle (in the form of a turbine

burning natural gas) and the Rankine cycle (in the form of a steam power plant)

18

Figure -2.3 P-V Chart of Dual Cycle

Gas Turbine Exhaust used as the heat source for the Steam Turbine cycle

Utilizes the major efficiency loss from the Brayton cycle

19

2.31 Major Combined Cycle Plant Equipment

Combustion Turbine (CT/CTG)

Steam Generator (Boiler/HRSG)

Steam Turbine (ST/STG)

Heat Rejection Equipment

Air Quality Control System (AQCS) Equipment

Electrical Equipment

Figure -2.4 Working Of a Combine Cycle Power Plant

20

Figure -2.5 Combined Cycle Plant Design

21

GT PRO 13.0 Drew Wozniak

1512 10-13-2004 23:27:31 file=C:\Tflow13\MYFILES\3P 0 70.gtp

Net Power 95959 kWLHV Heat Rate 7705 BTU/kWh

p[psia], T[F], M[kpph], Steam Properties: Thermoflow - STQUIK

4.717 m

Fogger

1X GE 6581B 2 X GT

33781 kW

12.54 p

90 T

30 %RH

944 m

4327 ft elev.

12.39 p

68 T

948.7 m

Natural gas 18.58 m

96 T 77 TLHV 369671 kBTU/h

149.2 p 684 T

143.2 p 2072 T

967.3 m

12.93 p 1034 T 1934.6 M

73.85 %N2 13.53 %O2 3.233 %CO2+SO2 8.497 %H2O 0.8894 %Ar

1031 T 1934.6 M

1031 897 569 568 538 534 481 419 326 268

268 T 1934.6 M

30813 kW

0.1296 M

FW

1.694 p 120 T 222.1 M

120 T

Natural gas 0 M

122 T 292.6 M

122 T 17.19 p 220 T

29

.58

M

17.19 p

220 T

29.65 M

LPB

29

.65

M

29

2.6

M

203.6 p

373 T

292.6 M

IPE2

203.6 p

383 T

36.75 M

IPB

199.7 p

460 T

36.75 M

IPS1

195.8 p

500 T

36.75 M

IPS2

924.2 p

472 T

251.1 M

HPE2

910.5 p

523 T

251.1 M

HPE3

910.5 p

533 T

248.6 M

HPB1

879.8 p

954 T

248.6 M

HPS3

850 p 950 T 248.6 M

87

9.8

p 9

54

T

6.89 M

183 p 375 T 70 M V4

26.36 M 19

5.8

p 5

97

T

V8

6.89 M

Figure -2.6 Combined Cycle Heat Balance

22

2.4 Other Specifications of Combined Cycles

Plant Efficiency ~ 58-60 percent

Biggest losses are mechanical input to the compressor and heat in the exhaust

Steam Turbine output

Typically 50% of the gas turbine output

More with duct-firing

Net Plant Output (Using Frame size gas turbines)

up to 750 MW for 3 on 1 configuration

Up to 520 MW for 2 on 1 configuration

Construction time about 24 months

Engineering time 80k to 130k labor hours

Engineering duration about 12 months

Capital Cost ($900-$1100/kW)

Two (2) versus Three (3) Pressure Designs

Larger capacity units utilize the additional drums to gain efficiency at the expense

of higher capital costs

Combined Cycle Efficiency

Simple cycle efficiency (max ~ 44%*)

23

Combined cycle efficiency (max ~58-60%*)

Correlating Efficiency to Heat Rate (British Units)

o h= 3412/(Heat Rate) --> 3412/h = Heat Rate*

o Simple cycle – 3412/.44 = 7,757 Btu/Kwh*

o Combined cycle – 3412/.58 = 5,884 Btu/Kwh*

Correlating Efficiency to Heat Rate (SI Units)

o h= 3600/(Heat Rate) --> 3600/h = Heat Rate*

o Simple cycle – 3600/.44 = 8,182 KJ/Kwh*

o Combined cycle – 3600/.58 = 6,207 KJ/Kwh*

Practical Values

o HHV basis, net output basis

o Simple cycle 7FA (new and clean) 10,860 Btu/Kwh (11,457 KJ/Kwh)

o Combined cycle 2x1 7FA (new and clean) 6,218 Btu/Kwh (6,560 KJ/Kwh)

2.5 Result and Conclusions

The results of using the combine cycle are as under:

Advantages:

Relatively short cycle to design, construct & commission

Higher overall efficiency

Good cycling capabilities

24

Fast starting and loading

Lower installed costs

No issues with ash disposal or coal storage

Disadvantages:

High fuel costs

Uncertain long term fuel source

Output dependent on ambient temperature

25

Chapter 3

Gas Turbine

Figure -3.1 Gas Turbine Diagram

3.0 Introduction

A gas turbine is a machine delivering mechanical power or thrust. It does this using a gaseous

working fluid. The mechanical power generated can be used by, for example, an industrial

device. The outgoing gaseous fluid can be used to generate thrust. In the gas turbine, there is a

continuous flow of the working fluid.This working fluid is initially compressed in the

compressor. It is then heated in the combustion chamber. Finally, it goes through the turbine.

26

The turbine converts the energy of the gas into mechanical work. Part of this work is used to

drive the compressor. The remaining part is known as the net work of the gas turbine.

3.1 History of gas turbines

• Invented in 1930 by Frank Whittle

• Patented in 1934

• First used for aircraft propulsion in 1942 on Me262 by Germans during second world war

• Currently most of the aircrafts and ships use GT engines

• Used for power generation

• Manufacturers: General Electric, Pratt &Whitney, SNECMA, Rolls Royce, Honeywell,

Siemens – Westinghouse, Alstom

Indian take: Kaveri Engine by GTRE (DRDO)

Gas Turbine Components

Figure -3.2 Gas Turbine Components

27

The gas turbine is comprised of three main components: a compressor, combustor and a turbine.

• The air is, compressed in the compressor (adiabatic compression-no heat gain or loss),

then mixed with fuel and burnt by combustor under constant pressure conditions in the

combustion chamber.

The resulting hot gas expands through the turbine to perform work (adiabatic expansion)

3.2 Classification of Gas Turbines

A. On basis of combustion process:

1. Continuous combustion or Constant pressure type

2. The explosion or constant volume type

B. On basis of path of working substance

1. Open cycle gas turbine

2. Closed cycle gas turbine

C. On basis of action of expanding gases:

1. Impluse turbine

2. Impulse- Reaction turbine

D. On the basis of direction of flow:

1. Axial flow

2. Radial flow

28

3.3 Working cycle:

Brayton Cycle

Figure 3.3 PV and TS Diagram Of Gas Turbine

Process 1-2:

Isentropic compression in the compressor

Process 2-3:

Addition of heat at constant pressure

Process 3-4:

Isentropic expansion of air

Process 4-1:

29

Rejection of heat at constant pressure

3.31 Calculating Mean Efficiency Of Gas Turbine Using Euler’s Equation

Mean performance for the stage can be calculated from the velocity triangles, at this radius,

using the Euler equation:

Hence:

where:

specific enthalpy drop across stage

turbine entry total (or stagnation) temperature

turbine rotor peripheral velocity

change in whirl velocity

The turbine pressure ratio is a function of and the turbine

efficiency.

3.32 PRINCIPLE OF OPERATION

• Intake

Slow down incoming air

Remove distortions

• Compressor

Dynamically Compress air

• Combustor

• Heat addition through chemical reaction

30

• Turbine

Run the compressor

• Nozzle/ Free Turbine

Generation of thrust power/shaft power

3.33 The ideal gas turbine cycle

Figure 3.5 Ideal Gast Turbine Cycle

The cycle that is present is known as the Joule-Brayton cycle. This cycle consists of four

important points.We start at position 1where the gas has passed through the inlet, after that the

gas then passes through the compressor. We assume that the compression is performed

isentropically. So, s1 = s2. The gas is then heated in the combustor. (Point 3.) This is done

isobarically (at constant pressure). So, p2 = p3. Finally, the gas is expanded in the turbine. (Point

4.) This is again done isentropic ally. So, s3 = s4.

The whole process is visualized in the temperature-entropy diagram as shown above. The cycle

consists of an isentropic compression of the gas from state 1 to state 2; a constant pressure heat

31

addition to state 3; an isentropic expansion to state 4, in which work is done; and an isobaric

closure of the cycle back to state 1.

Above Figure shows, a compressor is connected to a turbine by a rotating shaft. The shaft

transmits the power necessary to drive the compressor and delivers the balance to a power-

utilizing load, such as an electrical generator.When examining the gas turbine cycle, we do make

a few assumptions. We assume that the working fluid is a perfect gas with constant specific heats

cp and cv. Also, the specific heat ratio k (sometimes also denoted by ) is constant. We also

assume that the kinetic/potential energy of the working fluid does not vary along the gas turbine.

Finally, pressure losses, mechanical losses and other kinds of losses are ignored.

Classification

The gas turbine can be classified into two categories, i.e.

1)impulse gas turbine 2)reaction gas turbine.

If the entire pressure drop of the turbine occurs across the fixed blades, the design is impulse

type, while if the drop is taken place in the moving blades, the fixed blades serving only as

deflectors, the design is called reaction type.

The advantage of the impulse design is that there is no pressure force tending to move the wheel

in the axial direction and no special thrust balancing arrangement is required.There being no

tendency for gas to leak over the tips of the moving blades. A purely reaction turbine is not

generally used. In a small multi-stage construction the velocity change in the moving and fixed

blades is about the same, the design being 50% reaction types.

The turbine acts like the compressor in reverse with respect to energy transformation.

Most turbines operate in the range of 80% to 90% efficiency.

Construction

The basic construction of a gas turbine employs vanes or blades mounted on a shaft and enclosed

in a casing. The flow of fluid through turbine in most designs is axial and tangential to the rotor

32

at a nearly constant or increasing radius. There are two types of blades used in all turbines :

those that are fixed on the rotor and move with the shaft and those that are fixed to the casing and

help to guide and accelerate or decelerate the flow of fluid, being called fixed blades or vanes.

The power of the turbine depends upon the size, shape and the speed of the blades used.

Multi-staging is employed to increase the power output of the turbine by placing

additional sets of fixed and moving blades in series. To prevent leakage of gas along the shaft

gas seals or glands are provided where

the shaft emerges from the turbine casing. The extending lengths of the shaft on the two

sides of the turbine are supported on journal bearings which also maintain it’s proper alignment.

Inlet Guide Vanes

Collects and directs air into the gas turbine. Often, an air cleaner and silencer are part of the inlet

system. It is designated for a minimum pressure drop while maximizing clean airflow into the

gas turbine.

Exhaust System Directs exhaust flow away from the gas turbine inlet. Often a silencer is part of

the exhaust system. Similar to the inlet system, the exhaust system is designed for minimum

pressure losses

3.4 Accessories

There are several accessories fitted to the turbine. These are : a tachometer driven through a gear

box, an over speed governor, a lubricating oil pump and a fuel regulator. The starting gear is

mounted on the shaft at one end. The tachometer shows the speed of the machine and also

actuates the fuel regulator in case of speed rises above or fall below the regulated speed, so that

the fuel regulator admits less fuel or more fuel into the combustor and varies the turbine power

according to demand of load.

The governor back off fuel feed, if the exhaust temperature from turbine exceeds the safe limit,

33

thermal switches at the turbine exhaust acting on fuel control to maintain present maximum

temperature. The lubricating pump supplies oil to bearing under pressure. Other auxillaries used

on the turbine plant include the starting motor or engine with starting gear, oil coolers, filters and

inlet and exhaust mufflers. The turbine (and with it the compressors) is driven by the starting

motor through a clutch and set-up gearing. A standby motor driven pump is also provided for

emergency service. A failure of lubricating pump system results in stopping of the unit

automatically.

Aeroderivative gas turbines

Aeroderivatives are also used in electrical power generation due to their ability to be shut down,

and handle load changes more quickly than industrial machines. They are also used in the marine

industry to reduce weight. The General Electric LM2500, General Electric LM6000, Rolls-

Royce RB211 and Rolls-Royce Avon are common models of this type of machine.

Amateur gas turbines

In its most straightforward form, these are commercial turbines acquired through military surplus

or scrapyard sales, then operated for display as part of the hobby of engine collecting. In its most

extreme form, amateurs have even rebuilt engines beyond professional repair and then used them

to compete for the Land Speed Record

Table 3.6 Comparison between Heavy Duty and Aero Derivative Gas Turbine

34

Parameter Heavy Duty Aero-Derivative

Capital Cost, $/kW Lower Higher

Capacity, MW 10 - 330 5 – 100

Efficiency Lower Higher

Plan Area Size Larger Smaller

Maintenance Requirements Lower Higher

Technological Development Lower Higher

Auxiliary power units

APUs are small gas turbines designed to supply auxiliary power to larger, mobile, machines such

as an aircraft. They supply:

compressed air for air conditioning and ventilation,

compressed air start-up power for larger jet engines,

mechanical (shaft) power to a gearbox to drive shafted accessories or to start large jet

engines, and

electrical, hydraulic and other power-transmission sources to consuming devices remote

from the APU.

Industrial gas turbines for power generation

Industrial gas turbines differ from aeronautical designs in that the frames, bearings, and blading

are of heavier construction. They are also much more closely integrated with the devices they

power—electric generator—and the secondary-energy equipment that is used to recover residual

energy (largely heat).

They range in size from man-portable mobile plants to enormous, complex systems weighing

more than a hundred tonnes housed in block-sized buildings.

3.5 Results

Advantages

There are two big advantages:

Gas turbine engines have a great power-to-weight ratio compared to reciprocating

engines. That is, the amount of power you get out of the engine compared to the weight

35

of the engine itself is very good.

Gas turbine engines are also smaller than their reciprocating counterparts of the same

power.

The Gas Turbine Plant is simple in Design and Construction. It has few Reciprocating

Parts and is lighter in weight.

The Gas Turbine is quite useful in the regions where due to scarcity it is not possible to supply

water in abundance for raising steam.

Other advantages include:

Moves in one direction only, with far less vibration than a reciprocating engine.

Fewer moving parts than reciprocating engines.

Greater reliability, particularly in applications where sustained high power output is

required

Waste heat is dissipated almost entirely in the exhaust. This results in a high temperature

exhaust stream that is very usable for boiling water in a combined cycle, or for

cogeneration.Low operating pressures.

High operation speeds.

Low lubricating oil cost and consumption.

Can run on a wide variety of fuels.

Very low toxic emissions of CO and HC due to excess air, complete combustion and no

"quench" of the flame on cold surfaces

Disadvantages

The main disadvantage of gas turbines is that, compared to a reciprocating engine of the same

size, they are expensive. Because they spin at such high speeds and because of the high operating

temperatures, designing and manufacturing gas turbines is a tough problem from both the

engineering and materials standpoint.

Gas turbines also tend to use more fuel when they are idling and they prefer a constant

load rather than a fluctuating load. That makes gas turbines great for things like trans-continental

jet aircraft and power plants,

36

Chapter 4

Combustor And Compressor

Figure -4.1 Diagram Showing Combustion Chamber in a Gas Turbine

4.0 Introduction

A combustor is a device inside which the combustion of fuel takes place. For an efficient

operation of gas turbine plant, it is necessary to ensure good combustor performance. A good

combustor should achieve completeness of fuel combustion and the lowest possible pressure

drop in the gas, besides being compact, reliable and easy to control. Complete combustion of fuel

depends upon three factors, viz. temperature, time and turbulence. Temperature in the combustor

directly affects combustion and high temperature is conductive to rapid combustion.

37

The purpose of the combustor is to increase the energy stored in the compressor exhaust by

raising its temperature.

Adds heat energy to the airflow. The output power of the gas turbine is directly proportional to

the combustor firing temperature; i.e., the combustor is designed to increase the air temperature

up to the material limits of the gas turbine while maintaining a reasonable pressure drop.

4.01 Gas Turbine Combustor Arrangement

Figure -4.2 Combustor Arrangement

38

4.1 Compressor

Figure 4.3 Assembly of Gas Turbine Showing Compressor Chamber

4.11 Introduction

A compressor is a device that is used to supply compressed air to the combustion chamber.

Compressors are broadly classified as positive displacement type and rotodynamic type and may

be of single stage or multi-stage design. In the positive displacement machine, successive

volumes of air are pressurized within a closed space. These may be of reciprocating type or

rotary type. In reciprocating type machines, air is compressed by a piston in a cylinder, while in

the rotary type, this is accomplished by positive action of rotating elements.

The roto-dynamic compressors may be of radial flow, axial flow or mixed flow type. In these

machines, compression takes place by dynamic action of rotating vanes or impellers which

impart velocity and pressure to the air as it flows through the compressor. Roto-dynamic type

compressors include the centrifugal, axial and mixed flow compressors which are all high speed

machines running at as high as 3,000 to 4,000 RPM driven by turbines. These are designed to

have high value of air discharge capacity at moderate pressure. These types of compressors are

usually employed for gas turbine applications.

39

As air flows into the compressor, energy is transferred from its rotating blades to the air. Pressure

and temperature of the air increase. Most compressors operate in the range of 75% to 85%

efficiency.Provides compression, and, thus, increases the air density for the combustion process.

The higher the compression ratio, the higher the total gas turbine efficiency . Low compressor

efficiencies result in high compressor discharge temperatures, therefore, lower gas turbine output

power.

Figure 4.4 Compressors and Their Components

40

4.2 Results and Conclusions

The Conclusions drawn about the combustors are as under:

There are three main types of combustors, and all three designs are found in modern gas

turbines:

1. The burner at the left is an annular combustor with the liner sitting inside the outer

casing which has been peeled open in the drawing. Many modern burners have an

annular design.

2. The burner in the middle is an older can or tubular design. The photo at the top left

shows some actual burner cans. Each can has both a liner and a casing, and the cans are

arranged around the central shaft.

3. A compromise design is shown at the right. This is a can-annular design, in which the

casing is annular and the liner is can-shaped. The advantage to the can-annular design is

that the individual cans are more easily designed, tested, and serviced.

The details of mixing and burning the fuel are quite complex and require extensive testing for a

new burner. For our purposes, we can consider the burner as simply the place where combustion

occurs and where the working fluid (air) temperature is raised with a slight decrease in pressure.

The Isentropic efficiency of compressor obtained is:

Isentropic efficiency of Compressors:

is the enthalpy at the initial state

is the enthalpy at the final state for the actual process

is the enthalpy at the final state for the isentropic process

41

Chapter 5

Heat Recovery Steam Generator (HRSG)

5.0 Introduction

The Heat Recovery Steam Generator (HRSG) is a horizontal, natural circulation,

single pressure, water tube type steam generator with a single drum.

It is unfired type and uses Gas turbine exhaust gases as heat source.

It has been designed to generate superheat steam at a pressure of 41.5 kg/cm2 and a

temperature of 512 degree Celsius at a Main Stream Value (MSV).

5.1 Components of HRSG

It consists of following section :

1) Superheater section

2) Evaporator section

3) Economizer section

4) Condensate Pre heater (C.P.H) and components

5) Steel chimney

42

Figure 5.1 Components of HRSG

43

Figure -5.2 Actual Picture Of HRSG in GTPS

Figure -5.3 Flow Diagram of Gas Turbine Power Plant

44

Chapter 6

Transformer and Generator

6.0 Introduction to Transformers

Transformer is a device that transforms electrical energy form from one alternating voltage to

another alternating voltage without change in frequency.

IEEE defines transformer as a static electrical device, involving no continuously moving parts,

used in electric power system to transfer power between circuits through the use of

electromagnetic induction.

Figure -6.1 Transformer installed in GTPS

45

6.1 Types of transformer:

1) Power Transformer

2) Instrument Transformer

3) Auto Transformer

4) On the basis of working

4.1) Step down- converts H.V to L.V

4.2) Step up- converts L.V to H.V

Figure -6.2 Different types of Transformers

46

6.2 Introduction to Generator

Figure -6.3 Actual cut in section of a Generator

It is a device that generates electricity. It is coupled to the same shaft of turbine and runs at same

speed to that of the turbine. The capacity of generators depends on installed capacity of the plant.

The types of generators to be used depend on the purpose for which electrical energy is to be

produced.

Generator converts the mechanical energy of turbine shaft into electrical energy. Rotating field

type generators are employed which are ventilated by the fans of rotor shaft or separately driven

fans.

At this power plant the requirements of generator are:

POLES=2

FREQUENCY=50Hz

SPEED=120f/P=3000rpm

47

The class of generator under consideration is steam turbine-driven generators, commonly

called turbo generators. Generally they have the ratings up to 1900MW but here

3000rpm,50Hz generators are used of capacities 122MW.

6.3 Gas Turbine Generator Performance

Factors that Influence Performance

Fuel Type, Composition, and Heating Value

Load (Base, Peak, or Part)

Compressor Inlet Temperature

Atmospheric Pressure

Inlet Pressure Drop

Varies significantly with types of air cleaning/cooling

Exhaust Pressure Drop

Affected by addition of HRSG, SCR, CO catalysts

Steam or Water Injection Rate

Used for either power augmentation or NOx control

Relative Humidity

48

6.31 Altitude Correction

Table 6.4 Altitude Correction Graph

49

6.32 Humidity Correction

Table -6.5 Humidity Correction Graph

50

6.4 Result and Conclusions

Several conclusions can be drawn about the generators from the above thesis:

In the current situation, the cost of electricity continues to rise and thus, we should now be

willing to be inclined towards wind energy and solar energy. By learning to use a magnetic

generator, you can be assured of free and a life long generation of electricity. There are various

benefits of a magnetic electrical generator which are as follows:

1) Works in all types of weather conditions: Generally the wind and solar energy

alternatives rely much on natural phenomena, but in case of a magnetic generator, the

device would continue to perform well without depending upon weather conditions.

2) Safer to use: Evidently, the user is concerned with safety of power generators, as it

should be easy and safe to operate especially in houses.

3) Fits in a small space: It is very easy to install an eco-friendly magnetic generator and it

can fit even in a small, condensed place. Thus, these perpetual motion generators are

ideally suited for houses.

4) Minimum maintenance cost: Once these magnetic generators are constructed, they can

operate efficiently without any problems for long periods of time. Additionally, one need

not have to check them on a regularly basis and extra cost for generator maintenance can

be avoided.

5) Ability to reduce the power bill: The magnetic electrical generator can reduce an

individual’s power bill by about fifty percent. Thus, it is one of the best reasons for

anybody to own a magnetic electrical generator.

6) Ease in construction: Majority of people find it easy to build a magnetic electrical

generatorby themselves. Before constructing, one needs to abide by and understand the

step-by-step guide available on the internet. The whole process of construction would

take about few hours, and resources required for construction can be availed from a

hardware store.

51

Several disadvantages are also there while installing the generators like:

1) As we have already mentioned, the cost of diesel is very high compared to coal. This is

the main reason for which a diesel power plant is not getting popularity over other means

of generating power. In other words the running cost of this plant is higher compared to

steam and hydro power plants.

2) The plant generally used to produce small power requirement.

3) Cost of lubricants is high.

4) Maintenance is quite complex and costs high.

Conclusions About Transformers:

Advantages

1) Direct Oil Temperature

2) Simulated Winding Temperature

3) Calculated Winding Temperature (CT Models)

4) LTC Temperature Difference (LTC Models)

5) Single, Dual and Three Channel Units

6) Analog & Digital Inputs

7) Multi-Stage Fan/Pump control

8) Weatherproof Metal Case

9) SCADA Ready - DNP3.0 & Modbus Protocol

Disadvantages

1) Increased complexity and maintenance

2) Increased cost as fan packages may cost more than just adding material in smaller units

3) Additional energy losses and noise when fan motors are operated in higher loads

52

Chapter 7

Other Components Of Gas Turbine Power Station

7.0 Water Treatment Plant

The steam coming out of turbine is condensed and the condensate is feedback to the boiler as

feed water. Some water may be lost due to blow-down, leakage etc and to make up these losses

additional water called make up water, is required to be fed to the boiler.

The source of feed water contain impurities that could lead to scale formation.The water is

passed through alum-dosed clarifier which bonds impurities and thus removed.

Chlorine removes the algae and bacteria’s from the water. These processes takes place in

clarifier from where water is sent to D.M Plant (De-mineralized plant).

Figure 7.1 Water treatment plant

53

Figure -7.2 Anion and Cation Filters

7.01 Phases of Water treatment

Activated Carbon Filter: Water from the clarifier first comes in the ACF. It absorbs some of

the impurities.

Strong Acid Cation: It consists of resin named hydrocarbon. It removes the acidic impurities.

This is recharged by HCl acid.

Degasifier: Here the gases available in the water i.e. oxygen, carbon dioxide is removed upto

5-6%.

Strong Base Anion: It consists of resin, OH-.It removes the basic impurities. It is recharged

by NaOH. The pH is 8.5-9.5.

Mixed Bed: It consists of both resin, acid and basic. pH is maintained about 6.8-7.2.This is

recharged by HCl & NaOH.

54

7.1 SWITCH YARD

For any power station, switchyard is an important part which bridges the generating station and

the distribution system i.e. via switchyard the generated electricity is fed to the sub-stations. It

connects the GTPS to the northern grid. The switchyard of Gas Turbine Power Plant is of 66KV.

The voltage generated is 11KV, which is then step up to 66KV by generator transformer. This

66KV is fed to the 66KV switchyard.

The switchyard has the double bus bar system i.e. one is main bus and the other one is secondary

bus.

Some of the functions are:

Change voltage from one level to another

Switch transmission and distribution circuits into and out of the grid system.

Measure electric power qualities flowing in the circuits.

Eliminate lightning and other surges from the system.

Figure -7.3 Working of Switch Yard

55

7.11 Various Equipments installed in Switch Yard

Isolators: They are designed to open a ckt under no load. Its main purpose is to isolate

portion of the ckt from the other & is not intended to be opened while current is flowing

in the line.

Figure -7.4 Isolators

Circuit Breakers: It is a piece of equipment which can break the circuit automatically

under faulty conditions and make the circuit either manually or by remote control under

faulty conditions. They can be classified as

1) Oil ckt breaker

2) Gas(SF6) ckt breaker

3) Air-blast ckt breaker

4) Vaccum ckt breaker

The switch yard has gas (SF6) or Sulphur Hexa Fluoride ckt breaker

Figure -7.5 Circuit Breaker

56

Insulators: All the insulators are made of porcelain metal parts. They are free from radio

interference. They support the conductors (bus bar) and confine the current to the

conductors.

Figure7.6 – Insulators

Bus Couplers: Breakers are used as a bus coupler. They provide coupling between the

two bus bar of zones

.

Figure -7.7 Bus Couplers

57

Chapter 8

Result and Discussions

8.0 Positive Points of Gas Turbine Power Station:

Fuel efficiency:In conventional power plants turbines have a fuel conversion efficiency

of 33% which means two thirds of the fuel burned to drive the turbine off. The turbines in

combined cycle power plant have a fuel conversion efficiency of 50% or more, which means

they burn about half amount of fuel as a conventional plant to generate same amount of

electricity.

Low capital costs:The capital cost for building a combined cycle unit is two thirds the capital cost

of a comparable coal plant.

Commercial availability:Combined cycle units are commercially available from suppliers

anywhere in the world. They are easily manufactured, shipped and transported.

Abundant fuel sources:The turbines used in combined cycle plants are fuelled with natural gas,

which is more versatile than a coal or oil and can be used in 90% of energy publications. To

meet the energy demand now a day’s plants are not only using natural gas but also using other

alternatives like bio gas derived from agriculture.

Reduced emission and fuel consumption:Combined cycle plants use less fuel per kWh and produce

fewer emissions than conventional thermal power plants, thereby reducing the environmental

damage caused by electricity production. Comparable with coal fired power plant burning of

natural gas in CCPT is much cleaner.

58

Potential applications in developing countries:The potential for combined cycle plant is with

industries that requires electricity and heat or stem. For example providing electricity and steam

to a Sugar refining mill.

8.2 Negative Points of Gas Turbine Power Station:

The gas turbine can only use Natural gas or high grade oils like diesel fuel.

Because of this the combined cycle can be operated only in locations where these fuels are

available and cost effective.

Temp. of combustion chamber is too high, which results in shorter life time.

Gas turbine has low thermal efficiency

Has starting problem

Efficient only in combined cycle

8.3 Discussions

Combined cycle power plants meet the growing energy demand, and hence special attention

must be paid to the optimization of the whole system. Developments for gasification of coal and

use in the gas turbine are in advanced stages.

Once this is proven, Coal as the main fuel can also combined cycle power plants meet the

growing energy demand, be used in the combined cycle power plant.

The advances in cogeneration-the process of simultaneously producing useful heat and

electricity from the same fuel source-which increases the efficiency of fuel burning from 30% to

90%, thereby reducing damage to the environment while increasing economic output through

more efficient use of resources.

59

Chapter 9

Summary and Conclusions

9.0 Summary

Following specifications about the simple cycle gas turbine power plant are concluded throught

this thesis.

Simple Cycle

Operate When Demand is High – Peak Demand

Operate for Short / Variable Times

Designed for Quick Start-Up

Not designed to be Efficient but Reliable

Not Cost Effective to Build for Efficiency

Following specifications about the Combine cycle gas turbine power plant are concluded

throught this thesis.

60

Combined Cycle

Operate for Peak and Economic Dispatch

Designed for Quick Start-Up

Designed to Efficient, Cost-Effective Operation

Typically Has Ability to Operate in SC Mode

More recently, as simple cycle efficiencies have improved and as natural gas prices have fallen,

gas turbines have been more widely adopted for base load power generation, especially in

combined cycle mode, where waste heat is recovered in waste heat boilers, and the steam used

to produce additional electricity.

.

A Combined Cycle Power Plant produces high power outputs at high efficiencies (up to 55%)

and with low emissions. In a Conventional power plant we are getting 33% electricity only and

remaining 67% as waste.

By using combined cycle power plant we are getting 68% electricity.

It is also possible to use the steam from the boiler for heating purposes so such power plants can

operate to deliver electricity alone or in combined heat and power (CHP) mode.

9.1 Conclusions

Combined cycle power plants meet the growing energy demand, and hence special attention

must be paid to the optimization of the whole system.

Developments for gasification of coal and use in the gas turbine are in advanced stages.

Once this is proven, Coal as the main fuel can also combined cycle power plants meet the

growing energy demand, be used in the combined cycle power plant.

The advances in cogeneration-the process of simultaneously producing useful heat and

61

electricity from the same fuel source-which increases the efficiency of fuel burning from 30% to

90%, thereby reducing damage to the environment while increasing economic output through

more efficient use of resources.

62

References

1. http://ipgcl-ppcl.gov.in/ppcl.htm

2. http://ipgcl-ppcl.gov.in/powerstations.htm

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to-generate-1500-mw/articleshow/34166645.cms

4. IT Department, IPGCL-PPCL.

5. El-Wakil M.M, “Power Plant Technology”, Tata McGraw-Hill, 1984

6. Ramalingam K.K, “Power Plant Engineering”, Scitech Publications, 2002

7. Nagpal G.R,“Power Plant Engineering”, Khanna Publishers, 1998

8. Rai G.D, “Introduction to Power Plant Technology”, Khanna Publishers, 1995

9. [http://www.nptisr.com/AboutUs.htm About NPTI Southern Region

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11. http://www.ntpc.co.in/

12. http://www.delhitransco.gov.in

13. http://www.bsesdelhi.com

14. NDPL http://www.ndplonline.com

15. Electrical Engineer's Reference Book -edited by M A Laughton, M G Say

16. “Gas Turbine Theory” by Cohn H. Rogers, G.F.C. and Servanamutto. H.I.H

17. Steam Turbines and their Cycles” by Salisbury J.K

18. Axial Flow Turbines” by Horlock H.H

Appendix

65

To,

The Training & Placement Officer

Department of Mechanical Engineering Date:-12-05-2015

Al Falah University

Dhouj,Faridbad

Subject-“ Informing you about Internship certificate of a student of A.F.U.”

Respected sir,

We are hereby to inform you that Muneer Ahmed of Mechanical engineering branch bearing roll

no. ME-11-80 of 8th semester is doing Internship in Gas Turbine Power Station of I.P.G.C.L. in

order to complete his industrial training procedure of 4 months.

He joined G.T.P.S. on 27th January 2015 and his four

months training will be completed on 27th May 2015.So he will positively get his internship

certificate on or after 27th May 2015.

Thanking you

Your’s sincerely

……………………………………

(PIYUSH GUPTA)