Mechanical Engineering
Power Plant Engineering Comprehensive Theory with Solved Examples and Practice Questions
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First Edition: 2015 Second Edition (Revised & Updated) : 2016
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Preface This book was motivated by the desire to further the evolution of a concise book on Power Plant Engineering. Keeping in focus the importance of this subject in GATE and ESE, we have done a proper study and thereafter developed the content of the book accordingly. This edition has an expanded discussion of all relevant topics in the subject. Initially, we compiled the perceptions of our students on their problems in GATE and ESE while dealing with the questions from this subject. We identified their various problems like- lack of fundamentals of the subject, difficulty in solving simple questions, shortage of a complete study package, etc. These strengthened our determination to present a complete edition of Power Plant Engineering textbook. The book addresses all the requirements of the students, i.e. comprehensive coverage of theory, fundamental concepts, objective type problems and conventional problems, articulated in a lucid language. The concise presentation will help the readers grasp the concepts with clarity and apply them with ease to solve problems quickly. The book not only covers the entire syllabus of GATE and ESE, but also addresses the need of many other competitive examinations. Topics like ‘Steam Power Plant, Fuels and Combustion, Analysis of Steam Cycles, Cogeneration and Combined Cycle, Steam Turbines, Gas Turbine, Jet Engines, Reciprocating Air Compressors, Rotary Compressor, Compressible Fluid Flow & Nozzle and Nuclear Power Plants’, are given full coverage in line with our research on their importance in competitive examinations. We have put in our sincere efforts to present elaborate solutions for various problems, different problem solving methodology, some useful quick techniques to save time while attempting MCQs without compromising the accuracy of answers. A summary of important points to remember is added at the end of each topic. For the convenience of the readers, points to remember are specifically highlighted in the form of a note- both in theory as well as in solved examples. At the end of each chapter, sets of practice question are given with their keys, that will allow the readers to evaluate their understanding of the topics and sharpen their problem solving skills. Our team has made their best efforts to remove all possible errors of any kind. Nonetheless, we would highly appreciate and acknowledge if you find and share with us any printing, calculation and conceptual error. It is impossible to thank all the individuals who helped us, but we would like to sincerely thank all the authors, editors and reviewers for putting in their efforts to publish this book. With Best Wishes B. Singh CMD, MADE EASY
Contents
Power Plant Engineering
Chapter 1
Steam Power Plant................................... 1
2.9 Fans...................................................................................35
2.8
Draught (or Draft) System.........................................32
Objective Brain Teasers...........................................36
1.1 Introduction..................................................................... 1
Student’s Assignments............................................38
1.2 Boiler................................................................................... 1
1.3
Classification of Boilers................................................ 2
1.4
Fire Tube Boiler................................................................ 3
1.5
Water Tube Boilers......................................................... 3
Analysis of Steam Cycles........................39
1.6
Steam Drum..................................................................... 4
3.1 Introduction...................................................................39
1.7 Economisers..................................................................... 8
3.2
Carnot Cycle...................................................................39
1.8 Superheaters.................................................................... 9
3.3
Rankine Cycle................................................................41
1.9 Reheater..........................................................................10
3.4
Deviation of Actual Cycle from Theoretical
Chapter 3
Rankine Cycle................................................................44
1.10 Electro-Static Precipitator (ESP)..............................10
1.11 Ash Handling System..................................................11
3.5
Improvement in Rankine Cycle...............................44
1.12 Feedwater Treatment..................................................11
3.6
Super Critical Pressure Cycle....................................52
1.13 High Pressure Boiler....................................................12
3.7
Various Efficiencies of Steam Power Plants.........52
1.14 Super Critical Boiler (Once through or
Objective Brain Teasers...........................................59 Student’s Assignments............................................60
Monotube Boiler).........................................................14
1.15 Boiler Mountings..........................................................15
1.16 Boiler Accessories.........................................................15
Chapter 4
1.17 Comparison between “Fire Tube and Water
Cogeneration and Combined Cycle.......61
Tube”..........................................................................17
4.1 Introduction...................................................................61
1.18 Fluidized Bed Boiler.....................................................17
4.2
Back Pressure Turbine.................................................61
1.19 Steam Generator Control..........................................20
4.3
Pass-out Turbine...........................................................63
Objective Brain Teasers...........................................23
4.4
Combined Cycle Power Generation......................63
4.5
Characteristics of Ideal Working Fluid for Vapour
Student’s Assignments............................................25
Power Cycle....................................................................64
Chapter 2 Fuels and Combustion............................26
4.6
Binary Vapour Cycles...................................................64
4.7
Combined Cycle Plants..............................................65
Objective Brain Teasers...........................................71
2.1 Introduction...................................................................26
Student’s Assignments..............................................71
2.2 Coal...................................................................................26
2.3
Coal Analysis..................................................................27
2.4
Coal Properties..............................................................28
2.5
Actual Air-Fuel Ratio....................................................29
Steam Turbines.......................................72
2.6
Cooling Limit of Exhaust Gas...................................30
5.1 Introduction...................................................................72
2.7
Control of Excess Air....................................................31
5.2
Chapter 5
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Classification of Steam turbine...............................72
5.3
Simple Impulse Turbines...........................................73
7.3
Equation of Work (with Clearance Volume)..... 161
5.4
Compounding of Steam Turbines..........................73
7.4
Volumetric Efficiency (hvol)..................................... 162
5.5
Impulse Reaction Turbine.........................................76
7.5
Multistage Compression......................................... 164
5.6
Comparison of Impulse and Reaction Turbine...... 76
7.6
Effect of Clearance Volume.................................... 169
5.7
Impulse Turbine Analysis...........................................77
7.7
Actual P-V Diagram for Single-Stage
5.8
Reaction Turbine Analysis.........................................89
5.9
Parsons Turbine (50% reaction turbine)...............91
5.10 Enthalpy Drop in Various Stages.......................... 100
5.11 Losses in Steam Turbines........................................ 103
Compressor........................................................... 175
Student’s Assignments......................................... 180
Objective Brain Teasers........................................ 108
Chapter 8
Student’s Assignments......................................... 111
Rotary Compressor...............................181 8.1 Introduction................................................................ 181
Chapter 6 Gas Turbine...........................................112 6.1 Introduction................................................................ 112
6.2
Open Cycle Arrangements..................................... 112
6.3
Closed Cycle Arrangement.................................... 113
6.4
Requirements of the Working Medium............. 115
6.5
Advantages of Gas Turbines Over Reciprocating
Objective Brain Teasers........................................ 178
8.2
Centrifugal Compressor.......................................... 181
8.3
Axial Flow Compressors.......................................... 193
8.4
Comparison between the Centrifugal and Axial Flow Compressor............................................ 199
Engines......................................................................... 115
8.5
Roots Blower............................................................... 207
8.6
Vane Type Blower...................................................... 208
Objective Brain Teasers........................................ 213
Student’s Assignments......................................... 216
6.6
Ideal Open Gas Turbine Cycle (OGTC)................ 115
6.7
Actual Cycle Analysis............................................... 118
6.8
Optimum Pressure Ratio......................................... 122
Chapter 9
6.9
OGTC with Regeneration or Heat Exchange
Compressible Fluid Flow & Nozzle......218
Cycle....................................................................... 123
9.1 Introduction................................................................ 218
6.10 OGTC with Reheating.............................................. 125
9.2
Static Properties......................................................... 218
6.11 OGTC with Reheating and Regeneration......... 126
9.3
Stagnation Properties.............................................. 218
6.12 OGTC with Intercooling.......................................... 128
9.4
Velocity of Sound (Sonic Velocity)....................... 220
6.13 OGTC with Intercooling and Regeneration..... 129
9.5
One Dimensional Steady Isentropic Flow
6.14 OGTC with Intercooling and Reheating............ 130
6.15 OGTC with Intercooling, Reheating and
(Effect of Area Variation)......................................... 222 9.6 Nozzles.......................................................................... 224
Regeneration.............................................................. 131
9.7
Flow Through Nozzles............................................. 225
6.16 Comparison of Various Cycles............................... 141
9.8
Super Saturated Flow.............................................. 229
6.17 Performance Curves................................................. 142
9.9
Types of Nozzle.......................................................... 230
6.18 Polytropic Efficiency (hp)........................................ 144
9.10 Fanno and Rayleigh Lines...................................... 233
Objective Brain Teasers........................................ 153
Objective Brain Teasers........................................ 244
Student’s Assignments......................................... 156
Student’s Assignments......................................... 247
Chapter 7
Chapter 10
Reciprocating Air Compressors...........158
Nuclear Power Plants...........................248
7.1 Introduction................................................................ 158
10.2 Isotopes........................................................................ 249
7.2
Work Input for Compression Process................. 159
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10.1 Introduction................................................................ 248
10.3 Nuclear Stability and Binding Energy................ 249
10.4 Radioactive Decay and Half Life.......................... 250
10.5 Nuclear Reactor & Essential Components........ 252
Student’s Assignments......................................... 300
10.6 Selection of Fuel and Moderator......................... 253
10.7 Types of Reactors...................................................... 254
10.8 Pressurised Water Reactor (PWR)......................... 254
10.9 Boiling Water Reactor (BWR)................................. 256
10.10 CANDU Reactor.......................................................... 258
10.11 Gas Cooled Reactor.................................................. 259
10.12 Breeder Reactors....................................................... 259
10.13 Liquid Metal Fast Breeder Reactor (LMFBR)..... 260
10.14 Advantages and Disadvantages of Nuclear 10.15 Nuclear Waste Disposal........................................... 264
10.16 Nuclear Power Programme of India................... 264
10.17 Location of Nuclear Power Plant......................... 265
Objective Brain Teasers........................................ 297
Chapter 12 Steam Condensers, Cooling Tower & Air Ejector..............................................301
Steam Condenser
12.1 Introduction................................................................ 301 12.2 Vacuum......................................................................... 301
Power Plant........................................................... 263
11.15 Liquid Propellant Rockets...................................... 296
Objective Brain Teasers........................................ 266
12.3 Organs of a Steam condensing Plant................. 302
12.4 Classification of Condensers................................. 302
12.5 Jet Condensers........................................................... 302
Ejector Condenser
12.6 Surface Condensers.................................................. 304
12.7 Reasons for Inefficiency in Surface Condensers. . ....................................................307
Student’s Assignments......................................... 269
12.8 Comparison Between Jet and Surface Condensers.................................................................. 307
Chapter 11
12.9 Selection of Condenser........................................... 308
Jet Engines............................................270
12.10 Sources of Air in Condensers................................ 308
11.1 Introduction................................................................ 270
12.11 Effects of Air Leakage in Condenser................... 308
12.12 Method for Obtaining Maximum Vacuum in
11.2 Atmospheric Jet Engine or Air Breathing
Condensers ................................................................. 309
Engines.................................................................. 270
11.3 Rocket Engine or non Air Breathing Engines.. 270
12.13 Vacuum Measurement............................................ 309
11.4 Reciprocating or Propeller Engines.................... 270
12.14 Vacuum Efficiency..................................................... 310
11.5 Gas Turbine Engines................................................. 271
12.15 Condenser Efficiency............................................... 310
11.6 Ramjet Engines.......................................................... 271
12.16 Determination of Mass of Cooling Water......... 310
11.7 Pulse Jet Engine......................................................... 273
12.17 Heat Transmission through Walls of Tubes of a
11.8 Turboprop Engine..................................................... 275
11.9 Turbojet Engine......................................................... 276
12.18 Methods of Cleaning Condenser Tubes............ 312
11.10 Parameters Affecting Performance.................... 290
12.19 Cooling Tower............................................................. 313
11.11 Advantages of Jet Propulsion over Other
12.20 Dry Cooling Towers.................................................. 316
System.................................................................... 291
Air Ejector
11.12 Comparison of Relative Performances of Various
12.22 Air Ejector Working................................................... 320
Propulsion Power...................................................... 292
12.23 Air Ejector Theory...................................................... 320
11.13 Rocket Engine............................................................. 292
12.24 Appliction of Air Ejectors........................................ 321
11.14 Solid Propellant Rockets......................................... 295
Surface condenser.................................................... 311
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