ULTRA SUPERCRITICAL - The McIlvaine Company by pengxuebo

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Pulverized Coal-Fired Steam Generators
August 13, 2009

     Q: What is Ultra Supercritical (USC)?
     A: Not universally defined, but generally can be
     considered to be >3800 psig and >1100 F final steam
     Q: Why Consider Ultra Supercritical?
     A: Dramatic Improvement in Plant Efficiency
                   Economic Pressures – Fuel Prices
                   Environmental Pressures
                      Clean Air Act
                      Clear Skies
                      Local BACT
                      Future CO2
                   Social/Political Pressures
                   Quest for Permit

August 13, 2009



August 13, 2009
                                                            Operating Results

                                 Supercritical: Evolution
         Early Supercritical Units had problems
                 Lengthy start-ups
                 Poor load following flexibility
                 Poor availability
                 Slagging/fouling/corrosion
   Some of those problems not related to supercritical but
    other boiler evolution issues
   Most early design issues have been effectively addressed
    and availability has improved, though maintenance costs
    are relatively high
   Current supercritical designs in Europe and Japan have
    availability and maintenance commensurate with
    subcritical units

August 13, 2009
                                                                Operating Results

         Availability of Subcritical versus Supercritical Units – N. America
                                   (Data from NERC 1982-1997)


August 13, 2009
                                                     Operating Results

    Availability Data for Supercritical verses Subcritical Units (Europe)


August 13, 2009
                                                                                     Design Criteria

   Size
             Current commercial range from 300-1100 MW

 Steam Conditions
             Trade off efficiency gains (fuel savings) vs. capital cost
             Example: Change from 1000/1000 to 1100/1100 results in 3-5% overall increase in plant cost

 Fuel
             More difficult fuels (often less expensive) require designs higher in capital costs

 Feedwater Temperature
             Affected by cycle design

 Operating Requirements
             Base load, load following, cycling, on-off peaking

 Emissions Limits
             Current and future, including CO2


August 13, 2009
                                       Advanced Designs and Materials

      Recent Activities Assessing Ultra Supercritical Designs and
   DOE/NETL - Cost and Performance Baseline for Fossil Energy Plants – 2007
   EPRI – CoalFleet Guideline for Advanced Pulverized Coal Power Plants – 2008
   EPRI - Engineering and Economic Assessment of Ultra-Supercritical Pulverized
    Coal Power Plants for Near Term Development – Ongoing
   Thermie (Europe)
   Japanese Program
   U.S. - DOE and State of Ohio
   Shandong Technical Exchange – Henan Design Institute – Henan Province,


August 13, 2009
                                       Advanced Designs and Materials

                  Ultra Supercritical: Current State-of-the-Art

           Latest Units in Europe 4000 psig, 1105/1110 F
           China moving up to 3800 psig, 1120/1135 F
           Most aggressive unit in Japan 3950 psig, 1121/1153 F
           U.S. Market generally around 3700 psig, 1080/1080 F
           Most advanced U.S. plant in Engineering Phase at
            3800 psig, 1112/1135 F

           With advanced materials and careful design, Ultra
            Supercritical units have maintenance and availability
            similar to more recent standard supercritical units.

August 13, 2009
                  Advanced Designs and Materials


August 13, 2009
                                                   Advanced Design and Materials

Significant Issues with Ultra Supercritical Project Implementation
 Long term validation of materials
         ASME/ASTM Re-rating of materials: Grade 91, 92, 122, 23, etc.
         Creep-Rupture, exfoliation, corrosion resistance
    Fabrication
         Welding procedures, heat treatment, bending, etc.
    Construction
         Qualified crafts, qualification of procedures, tight Q/A
    Compatibility of valves, fittings and appurtenances
         Many shapes, valves, etc. not available in advanced materials

     Above issues present risks to project costs, schedule, and
    performance which are significant in comparison to standard
                subcritical or supercritical cycles.

August 13, 2009
                                                                   Future Generation USC

             Increase steam conditions to further improve efficiency:
                   For typical US facility, efficiencies up to 48% (HHV) achievable
                   Benefits include:
                      − Reduced emissions (including CO2)
                      − Lower CO2 capture costs per MWh

             Materials for advanced boilers:

                                                AD700 Program
                      Current                     UltraGen II             UltraGen III

                  1150°F (630°C)                1295°F (700°C)           1400°F (760°C)

                   Ferritic Steels             Austenetic alloys          Nickel based
                                               and nickel based           super alloys


August 13, 2009
                                                                                                           Future Generation USC

       100,000 Creep-Rupture Stress for USC Boiler Materials

 P.J. Maiasz, I.G. Wright, J.P Shingeldecker, T.B. Gibbons, and R.R. Romanosky, “Defining the Materials Issues and Research for Ultra-Supercritical Steam Turbines,” Proceedings to the
 Fourth International Conference on Advances in Materials Technology for Fossil Power Plants (Hilton Head, SC, Oct. 25-28, 2004). ASM-International, Materials Park, OH, 2005.     13

August 13, 2009
                                           Future Generation USC

                  Beyond Advanced Steam Conditions

        Double Reheat
        Reduction of Boiler Exit Gas Temperature
        Low Level Exit Gas Heat Recovery
        Coal Drying
        Combustion Air Preheating
        Feedwater Heater External Desuperheater
        Multi-Pressure Condenser
        Maximizing Cooling Tower Performance
        Optimized Turbine Cycle for Ambient Conditions
        Variable Speed Drives


August 13, 2009

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