Thermal Power Plant Pre Operational Activities Dipak K. Sarkar

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Thermal Power Plant Pre Operational Activities Dipak K. Sarkar

Contents

Preface ……………………………………………………………………………………………… xv
Acknowledgments ……………………………………………………………………………….. xxi
List of Acronyms/Abbreviations………………………………………………………………xxiii
Chapter 1: General Description of Thermal Power Plants ……………………………….. 1
1.1 Introduction……………………………………………………………………………………………… 1
1.1.1 Nuclear Power Plant ……………………………………………………………………………… 2
1.1.2 Hydel Power Plant………………………………………………………………………………… 6
1.1.3 Renewable Energy Power Plant ……………………………………………………………… 8
1.1.4 Integrated Gasification Combined Cycle (IGCC) …………………………………… 10
1.1.5 Magnetohydrodynamic (MHD) Generator……………………………………………… 11
1.1.6 Fuel Cell Power Plant………………………………………………………………………….. 11
1.1.7 Thermal Power Plant …………………………………………………………………………… 12
1.2 Steam Power Plant………………………………………………………………………………….. 14
1.2.1 Steam Generator …………………………………………………………………………………. 16
1.2.2 Steam Turbine…………………………………………………………………………………….. 23
1.3 Gas Turbine Power Plant…………………………………………………………………………. 27
1.4 Diesel-Generating Station………………………………………………………………………… 29
Reference …………………………………………………………………………………………………….. 31
Chapter 2: Quality Assurance and Quality Control
(Applicable to Preoperational Activities) …………………………………………………… 33
2.1 Introduction……………………………………………………………………………………………. 33
2.1.1 Quality Assurance……………………………………………………………………………….. 34
2.1.2 Quality Control …………………………………………………………………………………… 35
2.2 ISO 9000:2015—Quality Management Systems—Fundamentals
and Vocabulary………………………………………………………………………………………. 36
2.2.1 Definitions …………………………………………………………………………………………. 37
2.3 ISO 9001:2015—Quality Management Systems—Requirements…………………. 39
2.4 Procedure ………………………………………………………………………………………………. 41
References……………………………………………………………………………………………………. 42
PART 1 PREOPERATIONAL CLEANING OF VARIOUS
SUB-SYSTEMS 43
Chapter 3: Alkali Flushing of Preboiler System …………………………………………… 45
3.1 Introduction……………………………………………………………………………………………. 45
3.2 Description of Preboiler System ………………………………………………………………. 49
3.3 Precautions…………………………………………………………………………………………….. 51
3.4 Prerequisites…………………………………………………………………………………………… 51
3.4.1 Typical List of Apparatus…………………………………………………………………….. 53
3.4.2 Typical List of Safety Gadgets …………………………………………………………….. 53
3.5 Preparatory Arrangements……………………………………………………………………….. 53
3.6 Operating Procedure ……………………………………………………………………………….. 55
3.7 Estimation of Clarified Water, DM Water, and Chemicals …………………………. 59
3.7.1 Water-Holding Capacity………………………………………………………………………. 60
3.7.2 Clarified Water Requirement ……………………………………………………………….. 60
3.7.3 DM Water Requirement ………………………………………………………………………. 61
3.7.4 Chemical Requirement ………………………………………………………………………… 61
3.8 Conclusion …………………………………………………………………………………………….. 61
References……………………………………………………………………………………………………. 62
Chapter 4: Flushing of Fuel Oil Piping System ……………………………………………. 63
4.1 Introduction……………………………………………………………………………………………. 63
4.2 Description of Fuel Oil System………………………………………………………………… 68
4.2.1 Fuel Oil System of Steam Power Plant …………………………………………………. 68
4.2.2 Fuel Oil System of a Gas Turbine ………………………………………………………… 71
4.2.3 The Fuel Oil System of a Diesel Engine ……………………………………………….. 72
4.3 Precautions…………………………………………………………………………………………….. 73
4.4 Prerequisites…………………………………………………………………………………………… 74
4.4.1 Typical List of Bill of Materials …………………………………………………………… 75
4.4.2 Typical List of Safety Gadgets …………………………………………………………….. 75
4.5 Preparatory Arrangements……………………………………………………………………….. 76
4.5.1 Protection of Equipment………………………………………………………………………. 76
4.5.2 Mechanical Cleaning …………………………………………………………………………… 76
4.5.3 Erection of Temporary Tank, Piping, and Valves…………………………………… 78
4.5.4 Steam/Air Blowing or Water Washing of Fuel Oil Piping ………………………. 78
4.5.5 Installation of Fine Mesh Screen ………………………………………………………….. 80
4.5.6 Readiness of Auxiliaries………………………………………………………………………. 81
4.6 Operating Procedure ……………………………………………………………………………….. 81
4.6.1 Oil Charge………………………………………………………………………………………….. 81
4.6.2 Oil Circulation ……………………………………………………………………………………. 82
4.6.3 Duration of Oil Circulation ………………………………………………………………….. 82
4.7 Estimation of Flushing Oil ………………………………………………………………………. 83
4.8 Conclusion …………………………………………………………………………………………….. 83
References……………………………………………………………………………………………………. 84
viii Contents
Chapter 5: Blowing of Fuel Gas Piping System……………………………………………. 85
5.1 Introduction……………………………………………………………………………………………. 85
5.2 Description of Fuel Gas System……………………………………………………………….. 90
5.3 Precautions…………………………………………………………………………………………….. 90
5.4 Prerequisites…………………………………………………………………………………………… 92
5.4.1 Typical List of Bill of Materials …………………………………………………………… 93
5.4.2 Typical List of Safety Gadgets …………………………………………………………….. 94
5.5 Preparatory Arrangements……………………………………………………………………….. 94
5.6 Operating Procedure ……………………………………………………………………………….. 96
5.6.1 Natural Gas Blowing …………………………………………………………………………… 97
5.6.2 Compressed Air Blowing …………………………………………………………………….. 98
5.6.3 Compressed Nitrogen Blowing …………………………………………………………….. 99
5.6.4 Steam Blowing …………………………………………………………………………………… 99
5.6.5 Water Jet Flushing………………………………………………………………………………. 99
5.6.6 Pigging …………………………………………………………………………………………….. 100
5.7 Conclusion …………………………………………………………………………………………… 100
References………………………………………………………………………………………………….. 100
Chapter 6: Chemical Cleaning of a Steam Generator ………………………………….. 103
6.1 Introduction………………………………………………………………………………………….. 103
6.1.1 Drum-Type Steam Generator ……………………………………………………………… 112
6.1.2 Once-Through Steam Generator …………………………………………………………. 113
6.2 Precautions…………………………………………………………………………………………… 114
6.3 Prerequisites…………………………………………………………………………………………. 115
6.3.1 Typical List of Apparatus…………………………………………………………………… 117
6.3.2 Typical List of Safety Gadgets …………………………………………………………… 117
6.4 Preparatory Arrangements……………………………………………………………………… 118
6.5 Operating Procedure ……………………………………………………………………………… 119
6.5.1 Drum-Type Steam Generators…………………………………………………………….. 121
6.5.2 Once-Through Steam Generator …………………………………………………………. 122
6.6 Estimation of DM Water and Chemicals…………………………………………………. 126
6.6.1 Water-Holding Capacity…………………………………………………………………….. 126
6.6.2 Estimation of DM Water Requirement………………………………………………… 127
6.6.3 Estimation of Chemical Requirement………………………………………………….. 128
6.7 Conclusion …………………………………………………………………………………………… 129
References………………………………………………………………………………………………….. 130
Chapter 7: Flushing of Lube Oil Piping System …………………………………………. 131
7.1 Introduction………………………………………………………………………………………….. 132
7.1.1 Purpose and Type of Lubrication………………………………………………………… 134
7.1.2 Oil Coolers……………………………………………………………………………………….. 135
7.1.3 Oil Filters …………………………………………………………………………………………. 136
7.1.4 Oil Pumps ………………………………………………………………………………………… 136
7.1.5 Care and Supervision of a Lubrication System …………………………………….. 137
7.2 Description of the Lube Oil System ……………………………………………………….. 137
7.2.1 Lube Oil System of Steam Turbine …………………………………………………….. 137
7.2.2 Lube Oil System of Gas Turbine ………………………………………………………… 138
7.2.3 Lube Oil System of Diesel Engine ……………………………………………………… 139
7.3 Precautions…………………………………………………………………………………………… 141
7.4 Prerequisites…………………………………………………………………………………………. 142
7.4.1 Typical List of Bill of Materials …………………………………………………………. 143
7.4.2 Typical List of Apparatus…………………………………………………………………… 143
7.4.3 Typical List of Safety Gadgets …………………………………………………………… 143
7.5 Preparatory Arrangements……………………………………………………………………… 144
7.5.1 Mechanical Cleaning …………………………………………………………………………. 144
7.5.2 Chemical Cleaning ……………………………………………………………………………. 144
7.5.3 Water Washing of Factory Pickled (Chemically Cleaned)
Lube Oil Pipe Lines ………………………………………………………………………….. 146
7.5.4 Installation of Fine Mesh Screen ………………………………………………………… 147
7.5.5 Bypassing All Vulnerable Systems……………………………………………………… 147
7.5.6 Heating of the Flushing Oil………………………………………………………………… 148
7.5.7 Erection of Temporary Piping and Valves …………………………………………… 148
7.5.8 Readiness of Auxiliaries…………………………………………………………………….. 149
7.6 Operating Procedure ……………………………………………………………………………… 149
7.6.1 Oil Charge………………………………………………………………………………………… 149
7.6.2 Oil Circulation ………………………………………………………………………………….. 150
7.6.3 Purification of Flushing Oil During Circulation……………………………………. 151
7.6.4 Duration of Circulation ……………………………………………………………………… 151
7.6.5 Inspection and Cleaning …………………………………………………………………….. 152
7.6.6 Fresh Oil Filling and Circulation ………………………………………………………… 153
7.7 Estimation of DM Water, Chemicals, and Flushing Oil ……………………………. 153
7.7.1 Details of Lube Oil Piping …………………………………………………………………. 153
7.7.2 Estimation of DM Water Requirement………………………………………………… 154
7.7.3 Estimation of Chemical Requirement ………………………………………………….. 154
7.7.4 Estimation of Flushing Oil Requirement ……………………………………………… 154
7.8 Conclusion …………………………………………………………………………………………… 155
References………………………………………………………………………………………………….. 156
Chapter 8: Steam/Air Blowing of Main Steam, Cold Reheat, Hot Reheat
and Other Steam Pipe Lines ………………………………………………………………… 157
8.1 Introduction………………………………………………………………………………………….. 157
8.2 Description of Main Steam, Cold Reheat and Hot Reheat Steam,
and HP-LP Bypass System…………………………………………………………………….. 169
8.3 Precautions…………………………………………………………………………………………… 170
8.4 Prerequisites…………………………………………………………………………………………. 172
8.4.1 Typical List of Bill of Materials …………………………………………………………. 174
8.4.2 Typical List of Safety Gadgets …………………………………………………………… 175
8.5 Preparatory Arrangements……………………………………………………………………… 175
8.6 Operating Procedure ……………………………………………………………………………… 180
8.6.1 Steam Blowing …………………………………………………………………………………. 180
8.6.2 Compressed Air Blowing …………………………………………………………………… 185
8.7 Estimation of DM Water……………………………………………………………………….. 188
8.8 Estimation of Fuel Oil…………………………………………………………………………… 189
8.9 Conclusion …………………………………………………………………………………………… 190
References………………………………………………………………………………………………….. 191
PART 2 ACTIVITIES THAT MAKE CRITICAL EQUIPMENT
READY TO PUT THEM IN SERVICE 193
Chapter 9: Hydraulic Test of Steam Generator …………………………………………. 195
9.1 Introduction………………………………………………………………………………………….. 195
9.2 Objective……………………………………………………………………………………………… 197
9.3 Precautions…………………………………………………………………………………………… 197
9.4 Prerequisites…………………………………………………………………………………………. 198
9.4.1 Typical List of Bill of Materials …………………………………………………………. 198
9.4.2 Typical List of Safety Gadgets …………………………………………………………… 201
9.5 Preparatory Arrangements……………………………………………………………………… 201
9.6 Filling of Steam Generator…………………………………………………………………….. 204
9.6.1 Drum-Type Steam Generators…………………………………………………………….. 204
9.6.2 Once-Through Steam Generators………………………………………………………… 206
9.7 Operating Procedure ……………………………………………………………………………… 207
9.8 Estimation of DM Water and Chemicals…………………………………………………. 208
9.8.1 Estimation of DM Water……………………………………………………………………. 208
9.8.2 Estimation of Chemical Requirement………………………………………………….. 209
9.9 Conclusion …………………………………………………………………………………………… 209
References………………………………………………………………………………………………….. 210
Chapter 10: Air-Tightness/Leakage Test of the Furnace, Air, and Flue Gas Ducts
of a Steam Generator…………………………………………………………………………. 211
10.1 Introduction………………………………………………………………………………………… 211
10.2 Objective……………………………………………………………………………………………. 214
10.3 Precautions…………………………………………………………………………………………. 214
10.4 Prerequisites……………………………………………………………………………………….. 215
10.4.1 Typical List of Bill of Materials ……………………………………………………… 216
10.4.2 Typical List of Safety Gadgets ……………………………………………………….. 217
10.5 Preparatory Arrangements……………………………………………………………………. 217
10.5.1 Fossil Fuel–Fired Steam Generator………………………………………………….. 217
10.5.2 Heat-Recovery Steam Generator……………………………………………………… 218
10.6 Operating Procedure ……………………………………………………………………………. 218
10.6.1 Smoke Bomb Test …………………………………………………………………………. 219
10.6.2 Kerosene Test ……………………………………………………………………………….. 220
10.6.3 Soap Solution Test…………………………………………………………………………. 220
Contents xi
10.6.4 Noise Detection Test ……………………………………………………………………… 221
10.6.5 Flame Torch Test…………………………………………………………………………… 221
10.6.6 Pressure Drop Test ………………………………………………………………………… 222
10.7 Conclusion …………………………………………………………………………………………. 222
References………………………………………………………………………………………………….. 223
Chapter 11: Steam Generator Initial Firing and Drying Out of Insulation ………… 225
11.1 Introduction………………………………………………………………………………………… 225
11.2 Objective……………………………………………………………………………………………. 227
11.2.1 Boiler Mountings…………………………………………………………………………… 227
11.3 Precautions…………………………………………………………………………………………. 228
11.4 Prerequisites……………………………………………………………………………………….. 228
11.4.1 Typical List of Bill of Materials ……………………………………………………… 232
11.4.2 Typical List of Safety Gadgets ……………………………………………………….. 232
11.5 Brief Description of Various Systems …………………………………………………… 232
11.5.1 Clarified Water System………………………………………………………………… 233
11.5.2 DM Water System……………………………………………………………………….. 233
11.5.3 Auxiliary Cooling Water (ACW) System……………………………………….. 235
11.5.4 CCCW System…………………………………………………………………………….. 235
11.5.5 Compressed Air System……………………………………………………………….. 235
11.5.6 Fire Water System……………………………………………………………………….. 236
11.5.7 Auxiliary Steam System……………………………………………………………….. 237
11.5.8 Make-Up Water System……………………………………………………………….. 237
11.5.9 HP Chemical Dozing System………………………………………………………… 238
11.5.10 Burner Management System (BMS)………………………………………………. 238
11.5.11 Uninterrupted Power Supply (UPS) System……………………………………. 238
11.6 Preparatory Arrangements……………………………………………………………………. 238
11.7 Operating Procedure ……………………………………………………………………………. 240
11.7.1 Master Fuel Relay Trip (MFT) Conditions ………………………………………. 242
11.7.2 Furnace Purge ……………………………………………………………………………….. 243
11.8 Conclusion …………………………………………………………………………………………. 243
References………………………………………………………………………………………………….. 244
Chapter 12: Floating of Steam Generator Safety Valves ……………………………… 245
12.1 Introduction………………………………………………………………………………………… 245
12.2 Objective……………………………………………………………………………………………. 250
12.3 Precautions…………………………………………………………………………………………. 251
12.4 Prerequisites……………………………………………………………………………………….. 252
12.4.1 Typical List of Bill of Materials ……………………………………………………… 253
12.4.2 Typical List of Safety Gadgets ……………………………………………………….. 254
12.5 Preparatory Arrangements……………………………………………………………………. 254
12.6 Operating Procedure ……………………………………………………………………………. 255
12.6.1 Full Set Pressure Valve Actuation (Popping)……………………………………. 255
12.6.2 Lift-Assisted Valve Actuation…………………………………………………………. 258
12.7 Conclusion …………………………………………………………………………………………. 260
References………………………………………………………………………………………………….. 261
xii Contents
Chapter 13: Clean Air Flow Test of a Pulverizer……………………………………….. 263
13.1 Introduction………………………………………………………………………………………… 263
13.1.1 Classification of Mills ……………………………………………………………………. 265
13.2 Objective……………………………………………………………………………………………. 269
13.3 Precautions…………………………………………………………………………………………. 270
13.4 Prerequisites……………………………………………………………………………………….. 270
13.4.1 Typical List of Apparatus/Instruments……………………………………………… 272
13.4.2 Typical List of Safety Gadgets ……………………………………………………….. 273
13.5 Preparatory Arrangements……………………………………………………………………. 273
13.6 Operating Procedure ……………………………………………………………………………. 274
13.7 Conclusion …………………………………………………………………………………………. 274
References………………………………………………………………………………………………….. 276
Chapter 14: Condenser Flood and Vacuum Tightness Tests ………………………….. 277
14.1 Introduction………………………………………………………………………………………… 277
14.1.1 Circulating Water (CW) Cooled Condenser……………………………………… 278
14.1.2 Air-Cooled Condenser (ACC)…………………………………………………………. 281
14.1.3 Hybrid or Combination Water and Air Cooling………………………………… 282
14.2 Objective……………………………………………………………………………………………. 282
14.3 Precautions…………………………………………………………………………………………. 283
14.4 Prerequisites……………………………………………………………………………………….. 283
14.4.1 Typical List of Bill of Material and Apparatus/Instruments ……………….. 285
14.4.2 Typical List of Safety Gadgets ……………………………………………………….. 285
14.5 Preparatory Arrangements……………………………………………………………………. 286
14.6 Operating Procedure ……………………………………………………………………………. 287
14.6.1 Condenser Flood Test…………………………………………………………………….. 287
14.6.2 Condenser Vacuum Test ………………………………………………………………… 288
14.7 Conclusion …………………………………………………………………………………………. 289
References………………………………………………………………………………………………….. 290
Chapter 15: Generator Drying Out and Air-Tightness Tests…………………………. 291
15.1 Introduction………………………………………………………………………………………… 291
15.1.1 Generator Air/Hydrogen Cooling System…………………………………………. 293
15.1.2 Generator Stator Cooling Water System…………………………………………… 294
15.1.3 Generator Seal Oil System ……………………………………………………………… 295
15.2 Objective……………………………………………………………………………………………. 295
15.3 Precautions…………………………………………………………………………………………. 296
15.4 Prerequisites……………………………………………………………………………………….. 296
15.4.1 Typical List of Apparatus/Instruments……………………………………………… 296
15.4.2 Typical List of Safety Gadgets ……………………………………………………….. 298
15.5 Preparatory Arrangements……………………………………………………………………. 299
15.5.1 Generator Drying Out…………………………………………………………………….. 299
15.5.2 Generator Air-Tightness Test………………………………………………………….. 301
15.6 Operating Procedure ……………………………………………………………………………. 301
15.6.1 Generator Drying Out…………………………………………………………………….. 301
15.6.2 Generator Air-Tightness Test………………………………………………………….. 303
Contents xiii
15.7 Conclusion …………………………………………………………………………………………. 305
References………………………………………………………………………………………………….. 305
Chapter 16: Filling of Generator With Hydrogen and Protection Stability Test
of Generator ……………………………………………………………………………………. 307
16.1 Introduction………………………………………………………………………………………… 307
16.2 Objective……………………………………………………………………………………………. 309
16.3 Generator Hydrogen Filling …………………………………………………………………. 311
16.3.1 Prerequisites………………………………………………………………………………….. 311
16.3.2 Typical List of Bill of Materials/Instruments ……………………………………. 311
16.3.3 Typical List of Safety Gadgets ……………………………………………………….. 312
16.3.4 H2-CO2 System……………………………………………………………………………… 312
16.3.5 Precautions……………………………………………………………………………………. 313
16.3.6 Preparatory Arrangements………………………………………………………………. 316
16.3.7 Operating Procedure ………………………………………………………………………. 317
16.4 Protection Stability Test of Generator …………………………………………………… 318
16.4.1 Prerequisites………………………………………………………………………………….. 318
16.4.2 Typical List of Instruments …………………………………………………………….. 319
16.4.3 Precautions……………………………………………………………………………………. 319
16.4.4 Preparatory Arrangements………………………………………………………………. 319
16.4.5 Test Procedure ………………………………………………………………………………. 319
16.5 Conclusion …………………………………………………………………………………………. 326
References………………………………………………………………………………………………….. 327
Chapter 17: Completion Test of a Thermal Power Plant ……………………………… 329
17.1 Introduction………………………………………………………………………………………… 329
17.2 Objective……………………………………………………………………………………………. 330
17.3 Precautions…………………………………………………………………………………………. 330
17.4 Prerequisites……………………………………………………………………………………….. 330
17.5 Miscellaneous Tests…………………………………………………………………………….. 331
17.6 Reliability Run Test…………………………………………………………………………….. 333
17.7 Performance Guarantee (PG)/Performance Acceptance (PA) Tests ………….. 340
17.7.1 General Requirements ……………………………………………………………………. 340
17.7.2 Liquidated Damages (LDs) for Shortfall in Performance …………………… 342
17.7.3 Performance Guarantee/Acceptance Test Codes ……………………………….. 346
17.7.4 Performance Test Procedures………………………………………………………….. 350
17.8 Conclusion …………………………………………………………………………………………. 351
References………………………………………………………………………………………………….. 352
Appendix A: Brief Description on Performance Guarantee/Performance
Acceptance Tests ………………………………………………………………………………. 353
Appendix B: General Safety Guidelines …………………………………………………… 409
Appendix C: Tagging Procedure…………………………………………………………….. 423
Appendix D: Conversion Factors……………………………………………………………. 429
Index ……………………………………………………………………………………………… 435

Preface

I worked in the premier engineering consultancy firm of India, M/S Development Consultants
Private Limited (DCPL), for more than four decades. During this long tenure I had the
opportunity to work in innumerable thermal power plants of various sizes and configurations.
The most important part of this association was my exposure to chronological development in
power plant technology, both within and outside India. Against this backdrop, when I was
executing various projects I observed that there is a dearth of published books wherein various
aspects of preoperational activities are consolidated. This was the starting point in getting
motivated to write this book, Thermal Power Plant—Preoperational Activities, in which I tried
my utmost to incorporate the state-of-the-art technology applicable to these activities.
Design of a thermal power plant is a desktop study, while operation of the plant falls exclusively
within the purview of field engineering. In between design and operation there are certain areas,
generally known in the industry as preoperational activities. The procedure for execution of
these activities is developed during desktop study, but is executed in field only. So these
activities act as a go-between for design and operation to ensure unruffled power generation as
far as the end user is concerned. Thus, this book may be construed as complemental to my
previous book, Thermal Power Plant—Design and Operation, published by Elsevier.
This book aims to address some of the essential preoperational activities which are extremely
important to carry out in line with the practice followed in the industry globally. Smooth,
trouble-free, and economic operation of thermal power plants can be ensured if preoperational
activities are carried out with the utmost care in order to establish that prior to the start-up of
various systems, equipment, and/or the plant as a whole, they would be ready in all respects in
accordance with manufacturers’ recommendations, and at the same time fulfill all requirements
of applicable statutory guidelines. The main purpose of addressing the essential features of
preoperational activities is to ensure economic generation from a plant. Hence, the primary
focus of this book is on professional engineers.
The contents of the book are such that the book should not be treated as a conventional textbook
used in technical institutes. For design engineers, this book would act as a reference to help
them develop project-specific precommissioning manuals of a new plant. It would also fulfill
the needs of commissioning engineers, suppliers, and utility operators during the execution
period of new plants. While successful completion of preoperational activities is essentially to
be accomplished and certified prior to the start-up of new plants, areas addressed in this work
are applicable to running plants as well. In running plants, this book would be a tool to help
operation and maintenance engineers/suppliers (contractors) execute cleaning/testing activities
(eg, overhaul, critical inspection, major repair) successfully to comply with regulatory
requirements.
Degradation in the performance of major prime-movers—namely steam turbines, gas turbines,
and diesel engines—of running units is a common phenomenon in the industry. In order to arrest
the severity of degradation, it is generally recommended to undertake a major overhaul of these
prime-movers following a specified period of operating hours. In the case of steam turbines, this
period is usually 6 years, while for gas turbines and diesel engines, permissible operating hours
that are usually recommended by manufacturers are 48,000 and 8000, respectively. Steam
generators are generally inspected after about 12–24 months of operation to meet the statutory
requirements of the boiler inspectorate.Any defectobserved duringinspectionneeds to be attended
to before the boiler inspectorate extends permission to restart the steam generator.
In many countries initiatives have been undertaken to improve the efficiency and
environmental performance of their existing thermal power plants through refurbishment,
upgradation, rehabilitation, and modernization activities. Before putting these old plants into
service on completion of routine overhauls, on completion of renovation and modernization,
following a major repair, or after long shutdown of critical equipment or of the plant, it is
compulsory to carry out preoperational activities to meet statutory requirements; otherwise,
these plants would not be in a position to supply uninterrupted power.
Before discussing details of these activities, it is essential that readers are conversant with an
outline of a thermal power plant or that readers’ knowledge of a thermal power plant is
refreshed for the convenience of understanding various systems and equipment. Hence,
Chapter 1 addresses “General Description of Thermal Power Plants.” In addition, a generic
description of systems and equipment pertaining to specific types of preoperational activities or
thermal power plants is discussed substantially in various chapters.
Successful completion of a preoperational cleaning activity or a prestart-up activity depends on
how consciously each activity is carried out, such that a plant does not face any untoward
incident during normal running, lest generation gets perturbed. This is ensured by adhering to
the guidelines laid down by an internationally recognized quality management system (eg, ISO
9000). For the convenience of readers to adopt a foolproof quality management system,
guidelines on “Quality Assurance (QA) and Quality Control (QC) (Applicable to
Preoperational Activities)” are discussed in Chapter 2. Prior to conducting any preoperational
activity it is extremely essential to observe certain precautionary measures, and also to ensure
that certain activities/items are completed beforehand. These two aspects are addressed under
“Precautions” and “Prerequisites” in Chapters 3–17. The QA team must be responsible for
fulfilling these aspects. Thereafter the QC team takes over to ensure successful completion of
each preoperational activity, following the steps of developing preparatory arrangements,
operating procedures to be followed, availability of required materials (chemicals/water/any
special gadgets), availability of safety equipment, and so on.
Looking toward commissioning of a new plant or recommissioning of a running plant from
availability of electric power to commercial operation, the effective order of preoperational
activities that are generally followed in the industry are presented here:
1. Hydraulic test of steam generator
2. Airtightness/leakage test of the furnace, air, and flue gas paths of steam generator
3. Alkali flushing of preboiler system
4. Flushing of fuel oil piping system
5. Blowing of fuel gas piping system
6. Steam generator initial firing and drying out of insulation
7. Chemical cleaning of steam generator
8. Flushing of lube oil piping system
9. Steam/air blowing of main steam, cold reheat, hot reheat, and other steam pipe lines
10. Floating of steam generator safety valves
11. Clean airflow test of pulverizers
12. Condenser flood test and vacuum-tightness test
13. Generator drying out and airtightness test
14. Filling of generator with hydrogen and protection stability test of generator
15. Completion test of the power station
While some of the aforementioned activities pertain to the preoperational cleaning of piping
systems, the remaining activities are conducted to ensure the integrity of critical equipment.
Hence, preoperational activities, as laid down in this book, are addressed under Part 1 and Part 2,
as categorized here:
Part 1: Preoperational Cleaning of Various Sub-Systems
Preoperational cleaning of various piping systems of modern thermal power plants assumes
considerable importance because of the high-quality demand of flowing fluid, be it steam,
water, oil, or gas, through different pipe lines. During the process of manufacturing,
transportation, storing, and erection of various piping systems, in spite of taking the best
precautionary measures, a certain amount of dirt, mill scale, oil, grease, and so on finds its way
into these systems. These unwanted constituents need to be cleaned prior to putting into service
“erected new piping” or “replaced old piping.”
In running units, deposits may grow inside pipe lines due to improper water treatment or from
process contamination. Corrosion inside the pipe lines of operating units may take place either
Preface xvii
from an improperly controlled pH of demineralized makeup water or from concentration of
boiler water salts.
In order to get rid of these undesirable elements from the piping systems of both new units and
running units, as far as practicable, preoperational cleaning of piping systems is carried out.
Based on the type of flowing fluids through various piping systems, different types of cleaning
activities, as adopted in the industry, are discussed in the following chapters:
i. Chapter 3: Alkali flushing of preboiler system
ii. Chapter 4: Flushing of fuel oil piping system
iii. Chapter 5: Blowing of fuel gas piping system
iv. Chapter 6: Chemical cleaning of boiler
v. Chapter 7: Flushing of lube oil piping system
vi. Chapter 8: Steam/air blowing of main steam, cold reheat, hot reheat, and other steam
pipe lines
Part 2: Activities that Make Critical Equipment Ready to Put Them in
Service
This section addresses activities which are carried out to make critical equipment ready prior to
putting it in service and to establish the integrity of this equipment, along with its associated
systems. Activities covered in this section are:
i. Chapter 9: Hydraulic test of steam generator
ii. Chapter 10: Airtightness/leakage test of the furnace, air, and flue gas paths of steam
generator
iii. Chapter 11: Steam generator initial firing and drying out of insulation
iv. Chapter 12: Floating of steam generator safety valves
v. Chapter 13: Clean airflow test of pulverizers
vi. Chapter 14: Condenser flood test and vacuum-tightness test
vii. Chapter 15: Generator drying out and air-tightness test
viii. Chapter 16: Filling of generator with hydrogen and protection stability test of generator
ix. Chapter 17: Completion test of the power station
As a prequel to Chapter 17, “Brief Description of Performance Guarantee Tests” is addressed in
Appendix A.
Safety is a fundamental necessity for operating any plant. Hence, Appendix B lays down
“General Safety Guidelines.”
When a plant is in operation, under maintenance, or kept under mothballed condition, certain
valves/areas/systems purposefully need to be kept isolated. Any attempt to violate such
xviii Preface
isolation, even inadvertently, may lead to harm, injury, or major disaster of the plant and
personnel. In order to obviate such an inadvertent attempt of violation, warning tags of various
types are applied on isolated valves/areas/systems. Typical “Tagging Procedures” delineating
various warning content are therefore presented in Appendix C of this book.
In accordance with current global practice, SI units have been used throughout the book.
Nevertheless, for the convenience of readers, conversion factors from SI units to the metric
system of units to the imperial and US system of units are addressed in Appendix D.
Reader suggestions for the improvement of the contents of this book are welcome, and would
be acknowledged gratefully by the author.