W P C A. Worldwide Pollution Control Association. WPCA-Entergy Increasing Energy Efficiency of Existing Units Seminar January 22, 2014

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1 Worldwide Pollution Control Association WPCA-Entergy Increasing Energy Efficiency of Existing Units Seminar January 22, 2014 All presentations posted on this website are copyrighted by the Worldwide Pollution Control Association (WPCA). Any unauthorized downloading, attempts to modify or to incorporate into other presentations, link to other websites, or to obtain copies for any other purposes than the training of attendees to WPCA Conferences is expressly prohibited, unless approved in writing by the WPCA or the original presenter. The WPCA does not assume any liability for the accuracy or contents of any materials contained in this library which were presented and/or created by persons who were not employees of the WPCA. Visit our website at W P C A

2 Ways to Increase Turbine Efficiency and Improve Heat Rate Jim Auman Steam Turbine Engineering All Rights Reserved

3 Improving Efficiency and Heat Rate 3D Reaction Airfoils (Bowed) - Increased Stage Count - Reaction versus Impulse Designs - Proven Efficiency Improvement Advanced Control Stage Design Optimized Sealing Technology - Labyrinth Blade Path Seals - Spring-back and Retractable Seals - Sustainable Clearances Reduce Potential Leakage Paths Select LP Annulus Area for Best Efficiency 2

4 Industry Development of Airfoils Cylindrical Airfoil (since early 1900 s) constant profile section Twisted Airfoil (since late 70 s) variable profile sections adjustment to variable flow angles reduction of incidence loss 3D (since late 90 s) variable profile sections application of tangential lean or bow influence on radial pressure gradient reduction of secondary losses 3

5 3DV TM Current Generation Bowed Blading 3DS TM 3D with reduced Secondary losses 2 nd generation of advanced 3D blading based on twisted blades superimposed compound lean (bow) 3DV TM 3D blading with Variable stage reaction 3rd generation of advanced 3D blading based on 3DS blades optimized load distribution within the blade path achieve maximum overall blade path efficiency 4

6 3DS TM Blading Reduced Secondary Losses Modern 3DS TM blade η % > 2 % Cylindrical blading 3DS TM Blading Late 1990 s 3DS TM blading 2% efficiency improvement ψ 5

7 3DS TM Blading Pictorial 6

8 Advanced Control Stage Technology Past Features Turn around control stage Bolted on nozzle block Current - World Class Features Straight thru control stage Increased Impulse Chamber P & T Riveted, side entry rotating blade New, increased pitch airfoil section prevents HCF induced vane chipping Vane chipping calculation Improved airfoil profile design Contoured endwall nozzle Slide in nozzle block Triple pin rotating blade Improved materials Est. up to +3-5% CS η over Past Designs Modernized triple pin blade Contoured endwall Close pitch nozzles Increased pitch 7

9 Comparison of Blade Design Principles Impulse Stage 50% Reaction Stage V 1R V 1 U V 1R V 1 U V 2R V 2 U Fixed blade row accelerates the steam Moving blade row changes only the direction of the steam - High Work per Stage V 2R U V 2 Fixed blade row accelerates the steam Moving blade row changes both the speed and direction of the steam - Lower Peak Steam Velocity V1 - High Stage Count for Efficiency 8

10 Blade Path Sealing Technology HP Small Axial Expansion LP Large Axial Expansion Casing Casing Rotating Blade Rotating Blade Seal Optimization with Modern CFD-Tools Stationary Blade Stationary Blade Rotor Rotor 9

11 Sealing Technology Retractable Dummy Seal Rings TurboCare Retrofit: Brush Seals in Impulse Blade Path Benefits Reduction in leakage flow Improved efficiency Favorable wear behavior characteristics 10

12 Turbine Technology LP Last Stage Design Features L-0R Design Features Freestanding L-0 Full 3D Design Thin Trailing Edge Fir Tree Root Design Supersonic Airfoil Flame Hardened Leading Edges L-0C Design Features Thin Trailing Edge Welded Diaphragms Full 3D Design for optimum radial flow distribution and low exhaust loss Hollow Vanes Moisture Suction 11

13 Efficiency Improvement Summary 3D Reaction Airfoils (Bowed) - Increased Stage Count - Reaction versus Impulse Designs - Proven Efficiency Improvement Advanced Control Stage Design Optimized Sealing Technology - Labyrinth Blade Path Seals - Spring-back and Retractable Seals - Sustainable Clearances Reduce Potential Leakage Paths Select LP Annulus Area for Best Efficiency 12

14 Implementing New Technology for Improved Efficiency and Heat Rate Retrofit Turbine Modules 13

15 Improving Efficiency and Heat Rate Questions? 14