16
Comprehensive Theory with Solved Examples and Practice Questions Power Plant Engineering Mechanical Engineering Publications
Comprehensive Theory
with Solved Examples and Practice Questions
Power PlantEngineering
MechanicalEngineering
Publications
MADE EASY Publications
Corporate Office: 44-A/4, Kalu Sarai (Near Hauz Khas Metro Station), New Delhi-110016E-mail: [email protected]: 011-45124660, 8860378007
Visit us at: www.madeeasypublications.org
Power Plant Engineering© Copyright, by MADE EASY Publications.All rights are reserved. No part of this publication may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photo-copying, recording or otherwise), without the prior written permission of the above mentioned publisher of this book.
First Edition: 2015
Second Edition (Revised & Updated) : 2016
© All rights reserved by MADE EASY PUBLICATIONS. No part of this book may be reproduced or utilized in any form without the written permission from the publisher.
Publications
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
Preface
Chapter 1Steam Power Plant................................... 1 1.1 Introduction .................................................................... 1
1.2 Boiler .................................................................................. 1
1.3 Classification of Boilers................................................ 2
1.4 Fire Tube Boiler ............................................................... 3
1.5 Water Tube Boilers ........................................................ 3
1.6 Steam Drum .................................................................... 4
1.7 Economisers .................................................................... 8
1.8 Superheaters ................................................................... 9
1.9 Reheater .........................................................................10
1.10 Electro-Static Precipitator (ESP) .............................10
1.11 Ash Handling System .................................................11
1.12 Feedwater Treatment .................................................11
1.13 High Pressure Boiler ...................................................12
1.14 Super Critical Boiler (Once through or
Monotube Boiler) ........................................................14
1.15 Boiler Mountings .........................................................15
1.16 Boiler Accessories ........................................................15
1.17 Comparison between “Fire Tube and Water
Tube” .........................................................................17
1.18 Fluidized Bed Boiler ....................................................17
1.19 Steam Generator Control .........................................20
Objective Brain Teasers ..........................................23
Student’s Assignments ...........................................25
Chapter 2Fuels and Combustion ...........................26 2.1 Introduction ..................................................................26
2.2 Coal...................................................................................26
2.3 Coal Analysis .................................................................27
2.4 Coal Properties .............................................................28
2.5 Actual Air-Fuel Ratio ...................................................29
2.6 Cooling Limit of Exhaust Gas ..................................30
2.7 Control of Excess Air ...................................................31
2.8 Draught (or Draft) System ........................................32
2.9 Fans ..................................................................................35
Objective Brain Teasers ..........................................36
Student’s Assignments ...........................................38
Chapter 3Analysis of Steam Cycles .......................39 3.1 Introduction ..................................................................39
3.2 Carnot Cycle ..................................................................39
3.3 Rankine Cycle ...............................................................41
3.4 Deviation of Actual Cycle from Theoretical
Rankine Cycle ...............................................................44
3.5 Improvement in Rankine Cycle ..............................44
3.6 Super Critical Pressure Cycle ...................................52
3.7 Various Efficiencies of Steam Power Plants ........52
Objective Brain Teasers ..........................................59
Student’s Assignments ...........................................60
Chapter 4Cogeneration and Combined Cycle ......61 4.1 Introduction ..................................................................61
4.2 Back Pressure Turbine ................................................61
4.3 Pass-out Turbine ..........................................................63
4.4 Combined Cycle Power Generation .....................63
4.5 Characteristics of Ideal Working Fluid for Vapour
Power Cycle ...................................................................64
4.6 Binary Vapour Cycles ..................................................64
4.7 Combined Cycle Plants .............................................65
Objective Brain Teasers ..........................................71
Student’s Assignments .............................................71
Chapter 5Steam Turbines ......................................72 5.1 Introduction ..................................................................72
5.2 Classification of Steam turbine ..............................72
Power Plant EngineeringContents
(iv)
5.3 Simple Impulse Turbines ..........................................73
5.4 Compounding of Steam Turbines .........................73
5.5 Impulse Reaction Turbine ........................................76
5.6 Comparison of Impulse and Reaction Turbine ..... 76
5.7 Impulse Turbine Analysis ..........................................77
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
Objective Brain Teasers ....................................... 108
Student’s Assignments ........................................ 111
Chapter 6Gas 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
Engines......................................................................... 115
6.6 Ideal Open Gas Turbine Cycle (OGTC) ............... 115
6.7 Actual Cycle Analysis............................................... 118
6.8 Optimum Pressure Ratio ........................................ 122
6.9 OGTC with Regeneration or Heat Exchange
Cycle ...................................................................... 123
6.10 OGTC with Reheating ............................................. 125
6.11 OGTC with Reheating and Regeneration ........ 126
6.12 OGTC with Intercooling ......................................... 128
6.13 OGTC with Intercooling and Regeneration .... 129
6.14 OGTC with Intercooling and Reheating ........... 130
6.15 OGTC with Intercooling, Reheating and
Regeneration ............................................................. 131
6.16 Comparison of Various Cycles .............................. 141
6.17 Performance Curves ................................................ 142
6.18 Polytropic Efficiency (hp)........................................ 144
Objective Brain Teasers ....................................... 153
Student’s Assignments ........................................ 156
Chapter 7Reciprocating Air Compressors ..........158 7.1 Introduction ............................................................... 158
7.2 Work Input for Compression Process ................ 159
7.3 Equation of Work (with Clearance Volume) .... 161
7.4 Volumetric Efficiency (hvol) .................................... 162
7.5 Multistage Compression ........................................ 164
7.6 Effect of Clearance Volume ................................... 169
7.7 Actual P-V Diagram for Single-Stage
Compressor .......................................................... 175
Objective Brain Teasers ....................................... 178
Student’s Assignments ........................................ 180
Chapter 8Rotary Compressor ..............................181 8.1 Introduction ............................................................... 181
8.2 Centrifugal Compressor ......................................... 181
8.3 Axial Flow Compressors ......................................... 193
8.4 Comparison between the Centrifugal and
Axial Flow Compressor ........................................... 199
8.5 Roots Blower .............................................................. 207
8.6 Vane Type Blower ..................................................... 208
Objective Brain Teasers ....................................... 213
Student’s Assignments ........................................ 216
Chapter 9Compressible Fluid Flow & Nozzle .....218 9.1 Introduction ............................................................... 218
9.2 Static Properties ........................................................ 218
9.3 Stagnation Properties ............................................. 218
9.4 Velocity of Sound (Sonic Velocity) ...................... 220
9.5 One Dimensional Steady Isentropic Flow
(Effect of Area Variation) ........................................ 222
9.6 Nozzles ......................................................................... 224
9.7 Flow Through Nozzles ............................................ 225
9.8 Super Saturated Flow ............................................. 229
9.9 Types of Nozzle ......................................................... 230
9.10 Fanno and Rayleigh Lines ..................................... 233
Objective Brain Teasers ....................................... 244
Student’s Assignments ........................................ 247
Chapter 10Nuclear Power Plants ..........................248 10.1 Introduction ............................................................... 248
10.2 Isotopes ....................................................................... 249
(v)
(vi)
10.3 Nuclear Stability and Binding Energy ............... 249
10.4 Radioactive Decay and Half Life ......................... 250
10.5 Nuclear Reactor & Essential Components ....... 252
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
Power Plant .......................................................... 263
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 ....................................... 266
Student’s Assignments ........................................ 269
Chapter 11Jet Engines ...........................................270 11.1 Introduction ............................................................... 270
11.2 Atmospheric Jet Engine or Air Breathing
Engines ................................................................. 270
11.3 Rocket Engine or non Air Breathing Engines . 270
11.4 Reciprocating or Propeller Engines ................... 270
11.5 Gas Turbine Engines ................................................ 271
11.6 Ramjet Engines ......................................................... 271
11.7 Pulse Jet Engine ........................................................ 273
11.8 Turboprop Engine .................................................... 275
11.9 Turbojet Engine ........................................................ 276
11.10 Parameters Affecting Performance.................... 290
11.11 Advantages of Jet Propulsion over Other
System ................................................................... 291
11.12 Comparison of Relative Performances of Various
Propulsion Power ..................................................... 292
11.13 Rocket Engine ............................................................ 292
11.14 Solid Propellant Rockets ........................................ 295
11.15 Liquid Propellant Rockets ..................................... 296
Objective Brain Teasers ....................................... 297
Student’s Assignments ........................................ 300
Chapter 12Steam Condensers, Cooling Tower & Air Ejector .............................................301 Steam Condenser
12.1 Introduction ............................................................... 301
12.2 Vacuum ........................................................................ 301
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
12.8 Comparison Between Jet and Surface
Condensers ................................................................. 307
12.9 Selection of Condenser .......................................... 308
12.10 Sources of Air in Condensers ............................... 308
12.11 Effects of Air Leakage in Condenser .................. 308
12.12 Method for Obtaining Maximum Vacuum in
Condensers ................................................................ 309
12.13 Vacuum Measurement ........................................... 309
12.14 Vacuum Efficiency .................................................... 310
12.15 Condenser Efficiency .............................................. 310
12.16 Determination of Mass of Cooling Water ........ 310
12.17 Heat Transmission through Walls of Tubes of a
Surface condenser ................................................... 311
12.18 Methods of Cleaning Condenser Tubes ........... 312
12.19 Cooling Tower ............................................................ 313
12.20 Dry Cooling Towers.................................................. 316
Air Ejector
12.22 Air Ejector Working .................................................. 320
12.23 Air Ejector Theory ..................................................... 320
12.24 Appliction of Air Ejectors ....................................... 321
nnnn
