Description
Book SynopsisWhen installed and operated properly, general purpose steam turbines are reliable and tend to be forgotten, i.e., out of sound and out of mind. But, they can be sleeping giants that can result in major headaches if ignored. Three real steam turbine undesirable consequences that immediately come to mind are:
- Injury and secondary damage due to an overspeed failure. Anoverspeed failureon a big steam or gas turbine is one of the most frightening of industrial accidents.
- The high cost of an extensive overhaul due to an undetected component failure. A major steam turbine repair can cost ten or more times that of a garden variety centrifugal pump repair.
- Costly production loses due an extended outage if the driven pump or compressor train is unspared. The value of lost production can quickly exceed repair costs.
A major goal of this book is to provide readers with detailed operating procedure aimed at reducing these risks to minimal levels. Star
Table of Contents
Preface xiii
Acknowledgements xix
1 Introduction to Steam Turbines 1
1.1 Why Do We Use Steam Turbines? 1
1.2 How Steam Turbines Work 2
1.2.1 Steam Generation 5
1.2.2 Waste Heat Utilization 5
1.2.3 The Rankine Cycle 7
1.3 Properties of Steam 8
1.3.1 Turbine Design Confi gurations 11
1.4 Steam and Water Requirements 13
1.4.1 Steam Conditions for Steam Turbines 13
1.4.2 Water Conditions for Steam Turbines 13
1.4.3 Advantages of Steam Turbine Drives 14
1.4.4 Speed Control 16
1.4.5 Turbine Overspeed Protection 17
Questions 18
Answers 19
2 General Purpose Back Pressure Steam Turbine 21
2.1 Single-Stage Back Pressure Steam Turbine 22
2.1.1 Steam Flow Path 23
2.2 Mechanical Components in General Purpose Back Pressure Steam Turbines 31
2.2.1 Radial and Th rust Bearings 31
2.2.2 Bearing Lubrication 33
2.2.3 Force Lubrication Systems 37
2.2.4 Lubrication 38
2.2.5 Bering Housing Seals 40
2.2.6 Lip Seals 41
2.2.7 Labyrinth Seals 42
2.2.8 Steam Packing Rings and Seals 44
Questions 48
Answers 49
3 Routine Steam Turbine Inspections 51
Questions 56
Answers 56
4 Steam Turbine Speed Controls and Safety Systems 59
4.1 Introduction 59
4.2 Speed Controls 60
4.3 Governor Classes 68
4.4 Overspeed Trip System 77
4.5 Overpressure Protection 81
4.6 Additional Advice 83
Questions 83
Answers 84
5 The Importance of Operating Procedures 85
5.1 Steam Turbine Start-up Risks 87
5.2 Starting Centrifugal Pumps and Compressors 91
5.3 Steam Turbine Train Procedures 93
5.4 Training Options 95
Questions 97
Answers 98
6 Overspeed Trip Testing 101
6.1 Overspeed Trip Pre-test Checks 104
6.2 Uncoupled Overspeed Trip Test Procedure 106
6.3 Acceptance Criteria for Overspeed Trip Test 110
Questions 113
Answers 114
7 Centrifugal Pump and Centrifugal Compressor Start-ups with a Steam Turbine Driver 115
7.1 Centrifugal Pump and Steam Turbine Start-up 117
7.2 Centrifugal Compressor and Steam Turbine Start-up 125
Questions 134
Answers 134
8 Centrifugal Pump and Centrifugal Compressor Shutdowns with a Steam Turbine Driver 137
8.1 Centrifugal Pump Steam Turbine Shutdown 139
8.2 Centrifugal Compressor Steam Turbine Shutdown 141
Questions 144
Answers 145
9 Installation, Commissioning and First Solo Run 147
9.1 Introduction 147
9.2 Equipment Installation 148
9.2.1 Foundations 148
9.2.2 Grouting 150
9.2.3 Piping 157
9.3 Commissioning 160
9.3.1 Steam Blowing 162
9.3.2 Strainers 165
9.3.3 Lubrication 167
9.3.4 Oil Sump Lubrication 167
9.3.5 Flushing Pressure Lubricated System 169
9.3.6 Hydraulic Governors 172
9.4 Turbine First Solo Run on Site 174
9.4.1 First Solo Run Pre-checks 175
9.4.2 Steam Turbine First Solo Run Procedure 179
Questions 186
Answers 187
10 Reinstating Steam Turbine after Maintenance 189
10.1 Turbine Reinstatment after Maintenance 189
10.2 Reinstatement after Maintenance Check List 190
10.3 Steam Turbine Reinstatement after Maintenance Procedure 194
Questions 201
Answers 202
11 Steam Turbine Reliability 205
11.1 Repairs versus Overhauls 205
11.2 Expected Lifetimes of Steam Turbines and Their Components 206
11.3 Common Failure Modes 207
11.4 Improvement Reliability by Design 211
Questions 214
Answers 215
12 Introduction to Field Troubleshooting 217
12.1 Common Symptoms 219
12.2 Common Potential Causes 219
12.3 Troubleshooting Example #1 222
12.4 Troubleshooting Example #2 223
12.5 Steam Turbine Troubleshooting Table 225
12.6 Other Troubleshooting Approaches 229
Questions 231
Answers 232
13 Steam Turbine Monitoring Advice 235
13.1 What Is the Steam Turbine Speed Telling You? 236
13.1.1 Is the Steam Turbine Running at the Correct Speed? 236
13.1.2 Is the Speed Steady? 237
13.1.3 Is a Speed Swing Acceptable? 237
13.2 Assessing Steam Turbine Vibrations 238
13.2.1 What is Normal? 238
13.2.2 What are Some Causes of Vibration in Steam Turbines? 239
13.3 Steam Turbine Temperature Assessments 243
13.3.1 Bearing Temperatures 243
13.3.2 Oil Temperatures 243
13.4 Common Governor Control Problems 244
13.4.1 Steam Turbine Loss of Power 245
13.4.2 Steam Turbine Sealing 245
13.4.3 Oil Analysis as it Applies to Steam Turbines 247
13.4.4 Formation of Sludge and Varnish 248
13.4.5 Steam Piping and Supports 249
13.4.6 Steam Turbine Supports 250
13.4.7 Overspeed Trip Systems 251
13.5 Other Inspections 252
13.6 Good Rules of Th umb for Steam Turbines 253
Questions 255
Answers 256
14 Beyond Start-ups, Shutdowns, and Inspections 257
Appendix A: An Introduction to Steam Turbine Selection 261
Appendix B: Glossary of Steam Turbine Terms 289
Appendix C: Predictive and Preventative Maintenance Activities 299
Appendix D: Properties of Saturated Steam 301
Index 305
