Energy generation using exhaust then cooling- Report
Muneer GTPS
1. 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
2. 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
3. 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
4. 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
5. 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
6. 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
7. 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
8. 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
9. 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
10. 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
11. 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
12. 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
13. 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
14. 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
15. 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
16. 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
17. 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
18. 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
19. 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
20. 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
21. 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
22. 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
23. 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
24. 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
26. 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
27. 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.
2.01Mechanism
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.
2.02WorkingprincipleofCCTGplant
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
28. Figure -2.2 Combine Cycle Plant Diagram
2.03AirInlet
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
29. • 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 TurbineCycle
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.
2.05HeatRecoverySteamGenerator
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
30. 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.
2.21EfficencyofCCGTPlant
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
31. 2.22FuelsforCCPTPlants
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.
2.23EmissionsControl
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
32. 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
33. 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
36. 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
37. 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
38. 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
39. 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
40. 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
41. 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
42. 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
43. 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
44. • 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
45. 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
46. 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
47. 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
48. 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
49. 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.
50. 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
51. 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
52. 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
53. 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
54. 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
55. 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
56. 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
58. Figure -5.2 Actual Picture Of HRSG in GTPS
Figure -5.3 Flow Diagram of Gas Turbine Power Plant
44
59. 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
60. 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
61. 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
62. 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
65. 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
66. 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
67. 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
68. 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
69. 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
70. 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
71. 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
72. Chapter 8
Result and Discussions
8.0 Positive Points of Gas Turbine Power Station:
Fuelefficiency: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.
Lowcapitalcosts:The capital cost for building a combined cycle unit is two thirds the capital cost
of a comparable coal plant.
Commercialavailability:Combined cycle units are commercially available from suppliers
anywhere in the world. They are easily manufactured, shipped and transported.
Abundantfuelsources: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.
Reducedemissionandfuelconsumption: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
73. Potentialapplicationsindevelopingcountries: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
74. 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
75. 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
76. 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
77. References
1. http://ipgcl-ppcl.gov.in/ppcl.htm
2. http://ipgcl-ppcl.gov.in/powerstations.htm
3. http://economictimes.indiatimes.com/industry/energy/power/bawana-power-plant-ready
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
10.http://www.powermin.nic.in/research/training.htm
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
81. 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)
