Advances in Steam Turbines for Modern Power Plants

Advances in Steam Turbines for Modern Power Plants
Copyright
Contents
List of contributors
1 Introduction to steam turbines for power plants
1.1 Features of steam turbines
1.2 Roles of steam turbines in power generation
1.3 Technology trends of steam turbines
1.3.1 Steam turbines for thermal power plants (except combined cycle)
1.3.1.1 Increase steam temperature and pressure
1.3.1.2 Development of highly efficient last-stage long blades
1.3.1.3 Enhancement of efficiency
1.3.1.4 Enhancement of operational availability in low-load conditions and load-following capability
1.3.2 Steam turbines for combined-cycle power plants
1.3.3 Steam turbines for nuclear power plants
1.3.4 Steam turbines for geothermal, solar thermal, and bioenergy power plants
1.4 The aim of this book
References
2 Steam turbine cycles and cycle design optimization: the Rankine cycle, thermal power cycles, and integrated gasification-...
2.1 Introduction
2.2 Basic cycles of steam turbine plants
2.2.1 Rankine cycle
2.2.2 Theoretical thermal efficiency of the Rankine cycle
2.2.3 Influence of design parameter on thermal efficiency
2.2.3.1 Steam inlet pressure
2.2.3.2 Steam inlet temperature
2.2.3.3 Exhaust pressure
2.2.4 Reheat cycle
2.2.5 Regenerating cycle
2.2.6 Reheat–regenerating cycle
2.2.7 Calculation of thermal efficiency for the thermal power station
2.3 Types of steam turbines
2.3.1 Condensing turbine
2.3.2 Backpressure turbine
2.3.3 Extraction condensing turbine
2.3.4 Mixed-pressure turbine
2.4 Various steam turbine cycles and technologies to improve thermal efficiency
2.4.1 Steam turbine cycle for petrochemical plant
2.4.2 Gas- and steam-turbine-combined cycle
2.4.3 Cogeneration system
2.4.4 Ultra-supercritical pressure thermal power plant
2.4.5 Advanced USC pressure thermal power plant
2.4.6 Integrated coal gasification-combined cycle power plant
2.4.7 Advanced cycle
2.4.7.1 Triple-combined cycle
2.4.7.2 Supercritical CO2 cycle
2.4.7.3 Binary cycle
2.5 Conclusion
References
3 Steam turbine cycles and cycle design optimization: advanced ultra-supercritical thermal power plants and nuclear power p...
3.1 Introduction
3.2 Advanced ultra-supercritical thermal power plants
3.2.1 Progress of steam condition improvement in fossil-fired power plants
3.2.2 Cycle and turbine design optimization
3.2.3 Features of advanced ultra-supercritical turbines and technical considerations
3.3 Nuclear power plants
3.3.1 Cycle and features of boiling water reactor
3.3.2 Cycle and features of pressurized water reactor
3.3.3 Cycle and turbine design optimization
3.3.4 Features of nuclear turbines and technical considerations
3.3.5 Features of small modular reactor and its steam turbine
3.4 Conclusion
Acknowledgments
References
4 Steam turbine cycles and cycle design optimization: combined cycle power plants
4.1 Definitions
4.2 Introduction to combined cycle power plants
4.2.1 History of gas turbine combined cycle plants
4.3 Combined cycle thermodynamics
4.3.1 Thermal cycle overview
4.3.2 Heat recovery considerations
4.3.2.1 Heat source temperature
4.3.2.2 Steam generation pressure levels
4.3.2.3 Steam turbine impacts
4.3.2.4 Reheat
4.3.3 Efficiency definitions
4.3.3.1 First law
4.3.3.2 Second law
4.3.3.3 Efficiency drivers and tradeoffs
4.4 Markets served
4.4.1 Power generation
4.4.2 Cogeneration
4.4.3 District heating
4.4.4 Power generation+concentrated solar power
4.4.5 Integrated gasification combined cycle
4.4.6 Carbon capture and storage
4.5 Major plant systems overview
4.5.1 Plant configurations: single and multishaft
4.5.2 Gas turbine
4.5.3 Heat recovery steam generator
4.5.4 Steam turbine
4.5.5 Balance of plant
4.5.5.1 Heat rejection
4.5.5.2 Construction
4.5.6 Gas turbine combined cycle plant design considerations
4.5.6.1 Thermo-economics
4.5.6.2 Operability considerations
4.5.6.3 Turn down
4.6 Combined cycles trends
4.6.1 Steam conditions
4.6.2 Alternate bottoming cycle working fluids
4.7 Conclusion
References
5 Steam turbine life cycle cost evaluations and comparison with other power systems
5.1 Introduction
5.2 Cost estimation and comparison with other power systems
5.3 Technological learning
5.3.1 Technological change and technological learning
5.3.2 Application of technological learning on R&D investment
5.4 The modeling of technological learning
5.4.1 Learning curve definition
5.4.2 Two-factors learning curve
5.4.3 Technological learning combined with energy modeling
5.4.4 Application to sustainable energy system design
5.5 Conclusions
References
6 Design and analysis for aerodynamic efficiency enhancement of steam turbines
6.1 Introduction
6.2 Overview of losses in steam turbines
6.3 Overview of aerodynamic design of steam turbines
6.4 Design and analysis for aerodynamic efficiency enhancement
6.4.1 Blade profile design and analysis
6.4.2 Turbine blade and stage design and analysis
6.4.2.1 3D design and development of a short-blade stage
6.4.2.2 3D design and development of a long-blade stage
6.4.3 Design optimization of steam turbine blades and stages
6.5 Future trends
6.6 Conclusions
References
7 Mechanical design and vibration analysis of steam turbine blades
7.1 Categories of steam turbine blade vibration
7.1.1 Forced vibration of the blade
7.1.1.1 Vibration due to flow distortion
7.1.1.2 Vibration due to stage interaction force
7.1.1.3 Vibration due to shock load
7.1.1.4 Random vibration due to flow disturbance
7.1.2 Self-excited vibration of the blade
7.1.3 Vibration due to mistuned phenomena
7.2 Mechanical design of the blade
7.2.1 Summary of the mechanical design of the blade
7.2.2 Analysis of natural frequency
7.2.3 Analysis of resonant stress due to the stage interaction force
7.2.4 Analysis of the resonant response due to the shock load
7.2.5 Analysis of random vibration
7.2.6 Analysis of blade flutter
7.2.7 Analysis of blade damping
7.2.8 Analysis of mistuned system
7.3 Measurement and guideline for blade vibration
Reference
8 Steam turbine rotor design and rotor dynamics analysis
8.1 Categories of steam turbine rotor vibration
8.1.1 Forced vibration of a steam turbine rotor
8.1.1.1 Vibration due to rotor imbalance
Imbalance vibration due to errors in rotor geometry
Vibration due to thermal bending
Coupled vibration between turbine casing and foundation
8.1.1.2 Vibration due to fluid disturbance
8.1.2 Self-excited vibration of steam turbine rotor
8.1.2.1 Oil whip
8.1.2.2 Steam whirl
8.1.3 Torsional vibration
8.2 Mechanical design of steam turbine rotors
8.2.1 Overview of different rotor design and technology
8.2.2 Summary of mechanical design
8.2.2.1 Structure and geometry of the rotor
8.2.2.2 Design of bearings
8.2.2.3 Design of casing and foundation
8.2.3 Rotor dynamics analysis of steam turbine rotor
8.2.3.1 Analysis method and model (lateral vibration)
Model of rotor shaft
Model of bearing
Model of bearing support
Model of casing and foundations
Model of fluid force
8.2.3.2 Analysis method and model (torsional vibration)
8.2.4 Evaluation of rotor dynamics (lateral vibration)
8.2.4.1 Critical speed map
8.2.4.2 Q-factor diagram
8.2.4.3 Evaluation of rotor stability
8.2.5 Evaluation of rotor dynamics (torsional vibration)
8.3 Measurement and guidelines for rotor vibration
8.3.1 Measurement of steam turbine rotor vibration
8.3.2 Allowable rotor vibration
References
9 Steam turbine design for load-following capability and highly efficient partial operation
9.1 Introduction
9.1.1 Shortening the start-up time of turbines
9.1.2 Increasing the maximum load of plants
9.1.3 Lowering the minimum operation load of plants
9.1.4 Improving the load-following capability (controllability of load control) of plants
9.1.5 Improving the load-frequency response of plants
9.1.6 Contribution to grid system stabilization capability
9.2 Solution for grid code requirement
9.3 Load-frequency control of thermal power plants
9.4 Current capacity of thermal power governor-free operation and load-frequency control
9.5 Over load valve
9.6 Requirement for the accuracy of simulation models
9.7 Conclusion
References
10 Analysis and design of wet-steam stages
10.1 Introduction
10.1.1 An overview of wet-steam phenomena
10.1.2 Implications for turbine design
10.1.2.1 The effect of condensation on the flow field
10.1.2.2 Wetness losses
10.1.2.3 Droplet size distributions
10.2 Basic theory and governing equations
10.2.1 Gas-dynamic equations
10.2.2 Formation and growth of the liquid phase
10.2.2.1 Classical nucleation theory
10.2.2.2 Droplet growth
10.2.2.3 Heterogeneous effects
10.3 Numerical methods
10.3.1 Evaluation of steam properties
10.3.1.1 Look-up tables
10.3.1.2 Equations for subcooled steam
10.3.2 Fully Eulerian methods
10.3.3 The standard method of moments
10.3.3.1 The quadrature method of moments
10.3.4 Mixed Eulerian–Lagrangian calculations
10.3.5 Other methods
10.3.5.1 Streamline curvature calculations
10.3.5.2 Wake-chopping models
10.3.6 Examples of application
10.3.6.1 Nozzle flows
10.3.6.2 The international wet steam modeling project
10.3.6.3 Unsteady supercritical heat addition within nozzles
10.3.6.4 Comparison with cascade experiments
10.3.6.5 Unsteady multistage calculations
10.4 Measurement methods
10.4.1 Fine droplets
10.4.2 Coarse water droplets
10.4.3 Unsteady flow
10.4.4 Pitot loss measurements
10.5 Design considerations
10.5.1 Performance estimation in wet steam
10.5.2 Water droplet erosion
10.5.2.1 Erosion rate models
10.5.2.2 Erosion countermeasures
10.5.2.3 Coarse water droplets in steam turbines
Acknowledgments
Notation
References
11 Solid particle erosion analysis and protection design for steam turbines
11.1 Introduction
11.2 Susceptible area of erosion
11.3 Considerations on boiler design and plant design
11.4 Considerations on turbine design and operation mode
11.4.1 Size and number of blade
11.4.2 Operational mode (nozzle governing and throttle governing)
11.5 Result of erosion
11.5.1 Efficiency deterioration
11.5.2 Rotor vibration
11.6 Considerations of parameters on erosion and countermeasure
11.6.1 Effect of impinge angle
11.6.2 Effect of impinge velocity
11.6.3 Effect of material
11.6.4 Coatings
11.6.4.1 Boride coating
11.6.4.2 Chromium carbide coating by plasma spray
11.6.4.3 Other coatings
11.6.4.4 Blade profile
11.7 Conclusion
References
12 Steam turbine monitoring technology, validation, and verification tests for power plants
12.1 Introduction to power plant testing and monitoring
12.2 Performance type testing
12.2.1 Acceptance testing
12.2.2 Testing of steam turbines in fossil-fired units
12.2.3 Enthalpy drop test
12.2.4 Heat rate determination from testing
12.2.5 Full-scale ASME PTC 6 test
12.2.6 Alternative test ASME PTC 6
12.2.7 ASME PTC 6S test
12.2.8 Output capacity test
12.2.9 Testing of steam turbines in combined-cycle units
12.2.10 Testing of steam turbines in nuclear plants
12.3 Steam turbine component-type testing
12.3.1 Blade vibration testing
12.3.2 Steam turbine rotor train testing
12.3.3 Steam turbine structures testing
12.3.4 Steam turbine aerodynamic testing
12.4 Steam turbine monitoring
12.5 Summary
12.6 Power plant testing—a look ahead
References
13 Development in materials for ultra-supercritical and advanced ultra-supercritical steam turbines
13.1 Introduction
13.2 Efficiency improvement of ultra-supercritical and advanced ultra-supercritical turbines
13.2.1 Definition of ultra-supercritical and advanced ultra-supercritical
13.2.2 Efficiency of ultra-supercritical and advanced ultra-supercritical
13.3 Material development for ultra-supercritical steam turbines
13.3.1 General considerations
13.3.2 Rotor material
13.3.2.1 Rotor material for 566°C-class turbine (12Cr)
13.3.2.2 Material for 593°C-class turbine (modified 12Cr)
13.3.2.3 Material for 600°C–630°C-class turbine (new 12Cr)
13.3.2.4 Low-pressure turbine rotor
13.3.3 Blade material
13.3.4 Casting
13.4 Material development for advanced ultra-supercritical steam turbines
13.4.1 Rotor material
13.4.1.1 Design consideration and material selection for advanced ultra-supercritical turbines
13.4.1.2 Results of research and development
13.4.1.3 Rotor welding
13.4.1.4 High-temperature rotational test
13.4.2 Blade and bolt material
13.4.3 Casing and valve material
13.5 Conclusion
References
14 Development of last-stage long blades for steam turbines
14.1 Introduction
14.2 Design space for last-stage long blade development
14.3 Main features of modern last-stage blades
14.4 Design methodology for last-stage long blades
14.4.1 Technical features of last-stage long blades
14.4.1.1 High centrifugal force
14.4.1.2 Transonic, supersonic, and three-dimensional flow
14.4.1.3 Wet steam flow
14.4.1.4 Exhaust loss
14.4.1.5 Material and manufacturing for long and large blades and rotors
14.4.2 Aerodynamic design
14.4.2.1 One-dimensional design of high-pressure, intermediate-pressure, and low-pressure turbines
14.4.2.2 Through-flow design, profile design, three-dimensional design, and computational fluid dynamics analysis
14.4.2.3 Water droplet erosion assessment and erosion protection design
14.4.2.4 Exhaust loss and partial load efficiency assessment
14.4.3 Mechanical design
14.4.3.1 Blade height, hub diameter, and dovetail type selection
14.4.3.2 Blade cover and part-span damper
14.4.3.3 Three-dimensional mechanical design and static finite element analysis
14.4.3.4 Blade dynamic design and vibration assessment
14.4.4 Material selection and material tests
14.5 Model turbine tests and measurements
14.5.1 Efficiency and flow measurements
14.5.1.1 Aeromechanical and mechanical testing including very low-load conditions
14.6 Conclusions
References
15 Sealing designs and analyses for steam turbines
15.1 Introduction
15.2 Steam leakages in steam turbines and sealing designs
15.3 Impact of steam leakages on steam turbine efficiencies
15.4 Labyrinth seals
15.5 Joint surface sealing
15.6 Analysis and experiment for sealing designs
15.7 Advanced sealing technologies
15.7.1 Active clearance control
15.7.2 Brush seal
15.7.3 Leaf seal
15.7.4 Abradable seal
15.8 Conclusions
References
16 Advanced technologies for steam turbine bearings
16.1 Geometry of oil-film bearing
16.1.1 Journal bearings
16.1.1.1 Sleeve journal bearings
16.1.1.2 Tilting-pad journal bearings
16.1.2 Thrust and combined bearings
16.2 Bearing design
16.2.1 Thrust bearings
16.2.2 Journal bearings
16.2.3 Preload effects
16.2.4 Temperature and vibration measurements
16.2.5 Oil flow supply
16.3 Journal bearing testing
16.3.1 Tilting-pad journal bearing test-rig
16.3.1.1 Installed sensors
16.3.1.2 Experimental procedure
16.3.1.3 Results and discussions
Clearance profile and shaft center locus
Minimum oil-film thickness
Pressure distributions
Dynamic coefficients
16.3.2 Sleeve bearing test-rig
16.4 Thrust bearing testing
16.5 Bearing coating materials
16.5.1 Low friction alloys (white metals)
16.5.2 Polymeric materials
16.6 Reduction of bearing power loss
16.7 Conclusions
Acknowledgments
References
17 Steam valves and turbine inlet flow path design
17.1 Introduction
17.2 Steam turbine valves
17.2.1 Valve types
17.2.2 Turbine connections
17.2.3 Stop valve
17.2.4 Control valve
17.3 Steam turbine inlets
17.3.1 Design considerations
17.3.2 Design features
17.3.2.1 High-pressure steam turbines
17.3.2.2 Intermediate-pressure steam turbines
17.3.2.3 Low-pressure steam turbines
17.4 Conclusions
References
18 Advanced steam turbine technologies and countermeasures to neutralize the rapid load changes due to the increasing power...
18.1 Introduction
18.2 History of increasing the efficiency of coal-fired power generation to higher temperatures and pressure
18.3 Influence of the spread of renewable energy
18.4 Grid code
18.5 Primary response
18.6 Design and evaluation of low-pressure end blades
18.7 Fast start-up and thermal stress prediction
18.8 Measures to reduce thermal stress
18.9 Measures to decrease the minimum load
References
19 Manufacturing technologies for key steam turbine components
19.1 Introduction
19.2 Manufacturing documentation
19.3 Castings and forgings
19.4 Casings
19.5 Rotors
19.6 Blade manufacture
19.7 Inspection technologies
19.8 Conclusion
References
20 Steam turbine retrofitting for the life extension of power plants
20.1 Comprehensive maintenance planning and new technologies for steam turbine retrofitting
20.2 Age deterioration and lifetime of the steam turbine
20.2.1 Material deterioration
20.2.1.1 Creep
20.2.1.2 Embrittlement
20.2.1.3 Fatigue
20.2.1.4 Environment-assisted cracking
20.2.1.5 Stress corrosion cracking
20.2.1.6 Dynamic stress corrosion cracking
20.2.1.7 Corrosion fatigue
20.2.2 Performance deterioration
20.3 Outline of retrofitting for life extension
20.3.1 Steam turbine integrity inspection
20.3.2 Steam turbine life assessment program
20.3.3 Life extension and performance improvement
20.4 Technology for higher efficiency and other benefits
20.4.1 Performance improvement technology
20.4.1.1 Blade group efficiency
20.4.1.2 Seal technology
20.4.1.3 Other technologies
20.4.2 Repair technology
20.4.2.1 High-pressure/intermediate-pressure casing repair
20.4.2.2 Installation of high-pressure/intermediate-pressure casing cooling cell
20.4.2.3 Development of a new turbine frame for an integrity retrofit
20.5 Summary
References
21 Steam turbine retrofits for power increase and efficiency enhancement
21.1 Overview
21.2 Introduction
21.3 Improvement of plant performance
21.4 Key development processes
21.5 High-pressure and intermediate-pressure turbine retrofits
21.6 Low-pressure turbine retrofits
21.7 Summary
Nomenclature
References
22 Advanced geothermal steam turbines
22.1 Introduction
22.1.1 Outline of geothermal power generation
22.1.1.1 Dry steam system
22.1.1.2 Flash system
22.1.1.3 Back-pressure system
22.1.1.4 Binary cycle system
22.1.1.5 Total-flow system
22.1.1.6 Hybrid system
22.1.1.7 Enhanced geothermal system
22.1.1.8 Magma power generation
22.1.2 Brief history of geothermal power generation
22.2 Construction of modern geothermal steam turbines
22.2.1 Features of geothermal steam turbines
22.2.2 Types of geothermal steam turbines
22.2.3 Components and materials of geothermal steam turbines
22.2.3.1 Casing
22.2.3.2 Rotor
22.2.3.3 Blades
22.2.3.4 Valves
22.2.4 Design characteristics of the latest geothermal steam turbines
22.3 Technologies to enhance reliability of geothermal steam turbines
22.3.1 Corrosion problems and solutions
22.3.1.1 Evaluation of corrosion resistance of materials
22.3.1.2 Measures against stress corrosion cracking and corrosion fatigue
22.3.1.3 Measures against erosion–corrosion
22.3.2 Measures against water-droplet erosion
22.3.3 Measures against scale problems
22.4 Technologies to enhance performance of geothermal steam turbines
22.4.1 New-generation low-pressure blades for geothermal steam turbines
22.4.2 High-load, high-efficiency reaction blades
22.4.3 High-performance, compact exhaust casing
22.4.4 Performance improvement by retrofit of existing geothermal steam turbines
22.5 Operational experiences and lessons learned
22.5.1 Erosion
22.5.2 Erosion–corrosion
22.5.3 Stress corrosion cracking and corrosion fatigue
22.6 Future view of geothermal power generation and challenges
References
23 Steam turbines for solar thermal and other renewable energies
23.1 Introduction
23.2 Pilot plant of solar thermal and biomass binary generation system in Japan
23.3 The steam turbine for solar thermal technology
23.3.1 Features of the steam turbine
23.3.2 Steam condition and performance
23.3.3 Existing steam turbine size and steam condition
23.4 Steam turbine for organic Rankine cycle
23.4.1 Features of organic Rankine cycle systems and turbines
23.4.2 Centrifugal type organic Rankine cycle turbine
23.4.3 Screw type organic Rankine cycle turbine
23.4.3.1 Components of the organic Rankine cycle system
23.4.3.2 Screw turbine and generator system
23.5 Future applications
23.5.1 Combined system of concentrating solar power and biomass binary generation
23.5.2 Secondary use of the lower-temperature heat exhausted by the generating system
23.5.3 Organic Rankine cycle system application for ships
References
24 Advanced ultrasupercritical pressure steam turbines and their combination with carbon capture and storage systems
24.1 Introduction
24.2 Advanced ultrasupercritical turbine
24.3 Carbon capture technology
24.3.1 Concept of the technology
24.3.1.1 Precombustion capture
24.3.1.2 Oxy-fuel combustion
24.3.1.3 Postcombustion capture
24.3.2 Pilot plants and demonstration plants
24.3.2.1 Important pilot projects
24.3.2.2 The Tomakomai carbon capture and storage pilot plant
24.3.2.3 The Osaki coolgen pilot plant
24.3.2.4 Large-scale projects
24.3.3 Storage and utilization of carbon dioxide
24.3.3.1 Enhanced oil recovery
24.3.3.2 Enhanced coal bed methane recovery
24.3.3.3 Ocean storage
24.3.3.4 Mineral storage
24.3.3.5 Artificial photosynthesis
24.4 Combination of advanced ultrasupercritical turbine and carbon capture and storage
24.4.1 Comparison of three major technologies
24.4.2 Integration of carbon capture plant and power generation plant
24.4.2.1 Impact of turbine design
24.4.2.2 Consideration of pressure variation of the exhaust stage of an intermediate-pressure turbine
24.4.2.3 Decoupling one low-pressure turbine
24.4.2.4 Throttling the inlet pressure of a low-pressure turbine
24.4.2.5 Using a back-pressure turbine between the exhaust of the intermediate-pressure turbine and the inlet of the low-pr...
24.4.2.6 Combination of Case B and Case C
24.4.2.7 Unbalance of thrust force depending on the type of intermediate-pressure turbine
24.4.2.8 Efficiency penalty of last stage
24.5 Conclusions
References
25 Steam turbine roles and necessary technologies for stabilization of the electricity grid in the renewable energy era
25.1 Introduction
25.2 Issue of the renewable energy era
25.2.1 Adjustment function of supply and demand balance
25.2.2 Fluctuation of variable renewable energy
25.2.3 Issue of grid operating for the renewable energy era
25.3 Requirements of steam turbine power generation system
25.3.1 Quick start-up
25.3.2 Enhancement of output change rate
25.3.3 Enhancement of allowance of rotating speed
25.3.4 Improving minimum-load and implementation of net-zero power generation
25.4 Innovation and future technologies
References
26 Conclusions
26.1 Conclusions
Acknowledgments
Index