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New Generation Strategy Ultra-Supercritical Technology New Generation Strategy Ultra-Supercritical Technology Presented by: Tim Riordan, Manager New Generation.

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Presentation on theme: "New Generation Strategy Ultra-Supercritical Technology New Generation Strategy Ultra-Supercritical Technology Presented by: Tim Riordan, Manager New Generation."— Presentation transcript:

1 New Generation Strategy Ultra-Supercritical Technology New Generation Strategy Ultra-Supercritical Technology Presented by: Tim Riordan, Manager New Generation Design & Eng. APP Site Visit October 30 – November 4, 2006

2 2 AGENDA  Power Plant Steam Cycle – (Rankin Cycle)  History of Supercritical Units  Ultra-supercritical (USC) Overview  AEP Ultra-supercritical Design  Steam Generator Design  Turbine/Generator Design  Efficiency and Emissions Comparison

3 3 Typical Heat Balance

4 4 SCR NOx control added to meet NOx SIP Call. Additional NOx control greater than 85% FGDS to reduce SO2 by greater than 90% Low NOx Burners. NOx reduction greater than 50 % Bag filter to remove Particulate

5 5  Critical Point – 3208psi/705°F  Sub-Critical Steam Cycles : Water boiling to steam with pressures below ‘critical point’  Super-Critical Steam Cycles: Water to steam without boiling. Pressure above ‘critical point’  Ultra-Supercritical Steam Cycles: Steam temperatures above 1100 °F as defined by Electric Power Research Institute (EPRI) The Basic Heat Cycle

6 6 Gaining Efficiency Higher Pressure and Temperature Critical Point

7 7 The Evolution Continues Comparison Entropy Temperature Ultra Supercritical 1940 Vintage Subcritical Non-Reheat Early 20th Century Vintage Subcritical Non-Reheat 1960 Vintage Subcritical Reheat Supercritical

8 8 History of Supercritical Units  First Supercritical Unit: AEP Philo Unit 6  Initial Operation Date: 1957 (49 years ago)  125 MW  Steam Conditions: 4500psi/1150F/1050F/1000F (double-reheat)  World-wide – Over 200 units  Typical steam pressures: 3350 to 4200 psi  Typical steam temperatures: 1000 to 1050°F

9 9  What is USC Technology?  Defined by EPRI as Rankin Cycle steam temperatures above 1100°F  Limited to ASME code approved metallurgy for pressure part design  Higher temperatures increase cycle efficiency  USC technology is most efficient cycle available for selected fuels (sub-bituminous coal)  Higher efficiency = Less emissions  IGCC is limited for sub-bituminous coal applications Generating Technology: Ultra-Supercritical (USC) Pulverized Coal Plants

10 10 Generating Technology: Ultra-Supercritical (USC) Pulverized Coal Plants  An ultra-supercritical (USC) steam generation unit operates at supercritical pressure (typically 3500 psi or higher) and at steam temperatures above 1100 o F (593 o C).  For comparison, a conventional supercritical unit operates at steam temperatures of 1000-1050 o F (538-566 o C).  Modern chrome and nickel-based super alloys in the steam generator, steam turbine, and piping systems can withstand prolonged exposure to this high temperature steam.  By operating at elevated steam temperatures, the turbine cycle is more efficient. This reduces fuel (coal) consumption, and thereby reduces emissions.  USC technology is compatible with all types of coal.

11 11 Steam Generator Cross Section

12 12 AEP USC Steam Generator Design Conditions  Pulverized Coal-fired Benson Cycle, Spiral-wound Boiler  PRB Coal  Main Steam: 3675 psi/1115 F  Reheat Steam: 1130 F

13 13 USC Impact on Steam Generator  High Temperature Oxidation  Internal oxidation of boiler tubing above 1050 o F  Exfoliation of oxide layers leads to tube pluggage and could damage turbine blading.  SA-213-T91 material not used in heat transfer zone  Approaching limits of dissimilar metal weld (DMW) designs  DMW Design Limit = 1150 o F

14 14 Steam Generator Materials of Construction  SSH Outlet Bank: SA-213-347 HFG Stainless Steel  RH Outlet Bank: SA-213-347 HFG Stainless Steel  Superheater Headers : SA-335 –P92  Other alloys typical of previous supercritical designs

15 15 Steam Turbine/Generator Current Turbine Design for AEP USC Unit:  Four-casing, 3600 RPM, Tandem Compound, Single Reheat  Single-flow High-pressure (HP) turbine section  Double-flow Intermediate-pressure (IP) turbine section  Two (2) Double-flow Low-pressure (LP) turbine sections  Designed for full arc, sliding pressure operation  Improved Efficiency  Minimize Component Thermal Fatigue Damage

16 16 Steam Turbine/Generator Generator Design for AEP USC Unit:  Two-Pole, Three-Phase Synchronous Machine  840 MVA Rating  Direct Hydrogen cooled field and stator core  Direct water cooled stator windings

17 17 USC Impact on Turbine Higher operating temperatures call for improved materials of construction:  Most important components:  Forgings (rotors)  Castings (casings)  Piping  Material Requirements to handle USC operating conditions:  High creep rupture strength  Resistance against embrittlement  Low oxidation growth and no loosening of oxidation layer  Ease in manufacturing and availability

18 18 Turbine Materials of Construction  Main Steam and Reheat Steam Piping: SA-335-P92  Main Steam Valve Casing: 9Cr (CB2)  HP Inner Shell: 9Cr (CB2)  HP Rotor: 9Cr (FB2)  HP Rotating Blading – Inlet Stages: Nimonic (Ni80TiAl)  Nickel-based alloy  Superior to steel alloys at temperatures above 1050 o F

19 19 Efficiency and CO 2 Emissions Comparison

20 20 EmissionUltra SC 3800psi/1100F/1100F Supercritical 3500psi/1000F/1000F IGCC 2X1 7FB GT – Dry Feed Subcritical 2400psi/1000F/1000F SO 2 0.91 lb/MWh0.97 lb/MWh0.55 lb/MWh0.99 lb/MWh NOx 0.64 lb/MWh0.68 lb/MWh0.65 lb/MWh0.70 lb/MWh PM-10 0.14 lb/MWh0.15 lb/MWh0.09 lb/MWh0.15 lb/MWh CO 2 0.97 T/MWh1.03 T/MWh0.99 T/MWh1.06 T/MWh Emission Comparison Sub-Bituminous Coal

21 21 Conclusion  Ultra-supercritical Pulverized Coal Technology  Higher Temperatures = Better Efficiency  Better Efficiency = Less Emissions and Less Carbon Dioxide  Metallurgy Currently Available for Temperatures above 1100°F  Equipment Suppliers Can Guarantee Performance and Reliability


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