Operator's Guide to General Purpose Steam Turbines: An Overview of Operating Principles, Construction, Best Practices, and Troubleshooting

When 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.  An overspeed failure on 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.  Start-ups are complicated by the fact that operators must deal with numerous start-up scenarios, such as: Commissioning a newly installed steam turbine Starting ups after a major steam turbine repair Starting up a proven steam turbine after an outage Overspeed trip testing It is not enough to simply have a set of procedures in the control room for reference.  To be effective, operating procedures must be clearly written down, taught, and practiced—until they become habit.

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