Gas Turbine Combined Cycle Power Plants Gas Turbine Combined Cycle Power Plants S. Can Gülen MATLAB® and Simulink® are trademarks of The MathWorks, Inc. and are used with permission. The MathWorks does not w arrant the accuracy of the text or exercises in this book. This book’s use or discussion of MATLAB® and Simulink® software or related products does not constitute endorsement or sponsorship by The MathWorks of a par- ticular pedagogical approach or particular use of the MATLAB® and Simulink® software. CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2020 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-0-367-19957-9 (Hardback) This book contains information obtained from authentic and highly regarded sources. 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Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Contents Preface...............................................................................................................................................xi Author ............................................................................................................................................xiii Chapter 1 Introduction ..................................................................................................................1 1.1 Note on Units .....................................................................................................2 1.1.1 Odds and Ends ......................................................................................4 Chapter 2 Prerequisites .................................................................................................................7 2.1 Books and Periodicals .......................................................................................7 2.2 Software Tools ...................................................................................................8 2.3 Codes and Standards .......................................................................................11 References ..................................................................................................................14 Chapter 3 Bare Necessities .........................................................................................................15 3.1 Why Combined Cycle? ....................................................................................15 3.2 Combined Cycle Classification ........................................................................18 3.3 Simple Calculations .........................................................................................19 3.3.1 Design Performance ...........................................................................20 3.3.2 Off-Design Performance ....................................................................22 3.3.3 Lower or Higher Heating Value? ........................................................24 3.3.4 Gross or Net? ......................................................................................25 3.4 Operability .......................................................................................................27 References ..................................................................................................................31 Chapter 4 Gas Turbine ................................................................................................................33 4.1 Brief Overview ................................................................................................33 4.2 Rating Performance .........................................................................................38 4.3 Technology Landscape ....................................................................................39 4.4 Basic Calculations ...........................................................................................42 4.4.1 Heat and Mass Balance Analysis (First Law) ....................................42 4.4.2 Simplified Cycle Analysis ..................................................................48 4.4.3 Stage-by-Stage Gas Turbine Model ....................................................54 4.4.3.1 Turbine Aero .......................................................................55 4.4.3.2 Turbine Cooling ..................................................................64 4.4.3.3 Compressor Aero ................................................................65 4.5 Fuel Flexibility ................................................................................................71 References ..................................................................................................................73 Chapter 5 Steam Turbine ............................................................................................................75 5.1 Impulse versus Reaction ..................................................................................78 5.1.1 Steam Turbine Irreversibility .............................................................91 5.1.2 Supercritical Steam Turbine ...............................................................93 5.2 Last-Stage Bucket ............................................................................................95 v vi Contents 5.3 Basic Calculations .........................................................................................100 5.3.1 Steam-Path Efficiency ......................................................................103 5.3.2 Steam Cycle Simple Calculation ......................................................104 5.3.3 Steam Cycle Efficiency History .......................................................108 5.3.4 Exhaust End Analysis .......................................................................110 References ................................................................................................................112 Chapter 6 Heat Recovery Steam Generator (HRSG) ................................................................115 6.1 Fundamentals of Heat Recovery ...................................................................120 6.1.1 Heat Release Diagram ......................................................................120 6.1.2 HRSG Irreversibility ........................................................................121 6.1.3 HRSG Effectiveness .........................................................................122 6.1.4 Simplest Possible HRSG: One-Pressure, No Reheat ........................123 6.1.5 Next Level: Two-Pressure HRSG .....................................................129 6.1.6 The “Ultimate” HRSG: Three-Pressure with Reheat ......................133 6.1.7 Advanced Steam Conditions ............................................................136 6.2 HRSG Performance Calculations ..................................................................136 6.2.1 HRSG Pressure Loss ........................................................................137 6.2.1.1 Stack Effect .......................................................................138 6.2.2 Heat Transfer in the HRSG ..............................................................140 6.2.3 HRSG Steam Production .................................................................144 6.2.4 Stack Temperature ............................................................................146 6.3 Supplementary (Duct) Firing .........................................................................150 6.3.1 Practical Considerations ...................................................................154 6.3.2 Aeroderivative Gas Turbine Combined Cycle ..................................155 6.4 Supercritical Bottoming Cycle ......................................................................159 6.4.1 Feasibility of Supercritical Bottoming Steam Cycle ........................163 References ................................................................................................................164 Chapter 7 Heat Sink Options ....................................................................................................165 7.1 Water-Cooled Surface Condenser .................................................................167 7.2 Wet Cooling Tower ........................................................................................172 7.3 Circulating Water Pumps and Piping ............................................................176 7.4 Air-Cooled (Dry) Condenser .........................................................................177 7.5 Heat Sink System Selection ...........................................................................181 7.6 Heat Sink Optimization .................................................................................183 7.6.1 Two-Step Condensation ....................................................................185 References ................................................................................................................188 Chapter 8 Combining the Pieces ...............................................................................................189 8.1 Topping Cycle ................................................................................................189 8.2 Bottoming Cycle ............................................................................................191 8.2.1 Theory ..............................................................................................191 8.2.2 Practice .............................................................................................194 8.3 Combined Cycle ............................................................................................197 8.3.1 Second Law Analysis .......................................................................197 8.3.2 Optimum Combined Cycle Efficiency .............................................201 8.4 History ...........................................................................................................203 Contents vii 8.5 State of the Art ..............................................................................................215 8.6 The Hall of Fame ...........................................................................................221 8.6.1 Irsching .............................................................................................221 8.6.2 Bouchain ...........................................................................................222 8.6.3 Inland Empire Energy Center ..........................................................223 8.6.3.1 Steam-Cooled H Technology ............................................223 8.6.3.2 IEEC 107H........................................................................224 8.6.3.3 Fuel Gas Moisturization ...................................................225 8.6.4 60% Net (LHV) Bogey ....................................................................226 8.6.5 Epilogue............................................................................................228 References ................................................................................................................228 Chapter 9 Major Equipment ......................................................................................................231 9.1 Gas Turbine Package .....................................................................................231 9.2 Steam Turbine Package .................................................................................234 9.2.1 Steam Valves ....................................................................................236 9.2.2 Steam Seal Regulator (SSR) .............................................................238 9.2.3 Gland Seal Condenser (GSC) ...........................................................240 9.2.4 Turning Gear ....................................................................................240 9.2.5 Protective Features ...........................................................................240 9.3 Heat Recovery Steam Generator (HRSG) .....................................................241 9.4 AC Generator .................................................................................................247 9.5 Scope of Supply .............................................................................................251 References ................................................................................................................253 Chapter 10 Balance of Plant .......................................................................................................255 10.1 Electrical Equipment .....................................................................................255 10.1.1 Plant Controls ...................................................................................258 10.1.2 Plant Instrumentation .......................................................................260 10.2 Pipes and Valves ............................................................................................260 10.2.1 Steam System ...................................................................................263 10.2.2 Valves ...............................................................................................265 10.3 Pumps ............................................................................................................268 10.3.1 Pumps Shown in Plant Heat and Mass Balance ...............................268 10.3.2 Pumps Not Shown in Plant Heat and Mass Balance ........................269 10.3.3 Pump Selection and Design..............................................................269 10.4 Tanks .............................................................................................................273 10.5 Auxiliary Boiler ............................................................................................274 10.6 Fuel Gas Booster Compressor .......................................................................275 10.7 Fuel Gas Heating and Conditioning System .................................................276 10.8 Closed Cooling Water (CCW) System ..........................................................278 10.9 Water Facilities ..............................................................................................279 10.9.1 Why Treatment? ...............................................................................279 10.9.2 Once-Through (Benson) HRSG .......................................................283 10.9.3 Usage Minimization .........................................................................284 10.9.4 Wastewater Treatment ......................................................................285 10.9.5 Zero Liquid Discharge .....................................................................286 10.9.6 Water Balance ..................................................................................288 10.9.7 Deaeration ........................................................................................288 References ................................................................................................................292 viii Contents Chapter 11 Construction and Commissioning ............................................................................293 11.1 Procurement ...................................................................................................297 11.2 Construction ..................................................................................................298 11.3 Startup and Commissioning ..........................................................................301 11.3.1 HRSG Steam Blow ...........................................................................302 11.4 Acceptance Tests ...........................................................................................305 11.5 General Arrangement ....................................................................................309 Chapter 12 Environmental Considerations .................................................................................313 12.1 Air Permits ....................................................................................................315 12.2 Continuous Emissions Monitoring System (CEMS) ....................................321 12.3 Noise Abatement ...........................................................................................322 12.4 Selective Catalytic Reduction ........................................................................324 12.4.1 NOx Emission Calculations .............................................................325 References ................................................................................................................326 Chapter 13 Economics ................................................................................................................327 13.1 Price versus Cost ...........................................................................................327 13.2 Cost Estimation .............................................................................................330 13.2.1 Simplified .........................................................................................331 13.2.2 Detailed ............................................................................................338 13.3 Cost of Electricity ..........................................................................................342 13.4 Value of 1 Btu/kWh of Heat Rate..................................................................346 13.5 Bottoming Cycle “Optimization” ..................................................................348 13.5.1 LCOE Dissected ...............................................................................349 13.5.2 Two-Pressure or Three-Pressure? ....................................................353 References ................................................................................................................359 Chapter 14 Cogeneration.............................................................................................................361 Chapter 15 Operability ...............................................................................................................371 15.1 Steady-State Operation ..................................................................................374 15.1.1 Hot Day Power Augmentation ..........................................................384 15.1.2 Drum-Type versus Once-Through (Benson) Control .......................387 15.2 Transient Operation .......................................................................................391 15.3 GTCC Startup: Basics ...................................................................................393 15.3.1 Steam Turbine Roll ...........................................................................396 15.3.2 Steam Turbine Stress Control ...........................................................398 15.3.3 HRSG Stress Control .......................................................................399 15.4 GTCC Startup: Practical Considerations.......................................................401 15.4.1 Steam Bypass Systems .....................................................................403 15.4.2 HP Turbine Exhaust Temperature Control .......................................405 15.4.3 Fast versus “Slow” ............................................................................405 15.5 GTCC Shutdown ...........................................................................................408 15.6 Emergencies ...................................................................................................410 15.7 Grid Code Compliance ..................................................................................412 References ................................................................................................................417 Contents ix Chapter 16 Maintenance .............................................................................................................419 16.1 Maintenance Costs ........................................................................................421 16.2 Important Metrics ..........................................................................................424 16.2.1 Availability Calculation Example ....................................................428 16.3 Failure Mechanisms ......................................................................................431 References ................................................................................................................437 Chapter 17 Repowering ..............................................................................................................439 17.1 Which Repowering? ......................................................................................441 17.2 Cost of Repowering .......................................................................................442 17.3 An Example Calculation ...............................................................................444 17.4 Takeaways ......................................................................................................450 References ................................................................................................................451 Chapter 18 Integrated Gasification Combined Cycle .................................................................453 18.1 Syngas-Fired Gas Turbine .............................................................................457 18.2 Bottoming Cycle ............................................................................................460 18.3 Gasification ....................................................................................................462 18.3.1 Gasifier Types ...................................................................................462 18.3.2 Cold Gas Efficiency ..........................................................................462 18.3.3 Gasifier Heat Recovery ....................................................................464 18.3.4 Air Separation Unit ..........................................................................464 18.3.5 Syngas Cleanup ................................................................................466 18.3.6 Syngas Expander ..............................................................................467 18.3.7 Syngas Heating and Moisturization .................................................467 18.3.8 Carbon Capture and Sequestration...................................................468 18.4 Example .........................................................................................................470 References ................................................................................................................474 Chapter 19 Carbon Capture ........................................................................................................475 19.1 Post-Combustion Carbon Capture Basics......................................................476 19.1.1 State of the Art .................................................................................476 19.1.2 A Novel Method ...............................................................................478 19.1.3 A Novel Operating Strategy .............................................................480 19.2 Simple Calculations .......................................................................................483 References ................................................................................................................485 Chapter 20 What Next? ...............................................................................................................487 Appendix A: Property Calculations ...........................................................................................491 Appendix B: Standard Conditions for Temperature and Pressure ........................................497 Appendix C: Exergetic Efficiency ...............................................................................................499 Appendix D: Thermal Response Basics .....................................................................................503 Appendix E: Steam Turbine Stress Basics ................................................................................507