Power Plant Primer - Combustion Turbines by yurtgc548

VIEWS: 108 PAGES: 54

									Gas Turbine Technologies
 for Electric Generation
             by
      Rob Shepard, P.E.

                             www.Neel-Schaffer.com
                          rob.shepard@neel-schaffer.com
Gas Turbine Basics

    Gas Turbines
        Types
        How They Work
        Applications
        Components of Plant
        Flow Paths
        Operation




 2
Gas Turbine Applications


 Simple Cycle
 Combined Cycle
 Cogeneration




    3
Types of Gas Turbine Plants

    Simple Cycle
        Operate When Demand is High – Peak Demand
        Operate for Short / Variable Times
        Designed for Quick Start-Up
        Not designed to be Efficient but Reliable
             Not Cost Effective to Build for Efficiency
    Combined Cycle
        Operate for Peak and Economic Dispatch
        Designed for Quick Start-Up
        Designed to Efficient, Cost-Effective Operation
        Typically Has Ability to Operate in SC Mode


 4
Principles of
Operation
    Open Cycle
Also referred to as simple cycle)




       The energy contained in a flowing ideal gas
        is the sum of enthalpy and kinetic energy.
       Pressurized gas can store or release energy.
        As it expands the pressure is converted to
        kinetic energy.
                                                       Link to picture
    5
Brayton Cycle – Gas Turbine Cycle




 6
Thermodynamic Fundamentals
   Pressure Ratio &
    CT Components




    7
Combustion or Gas Turbine




 8
Principles of Operation
  Compressor
   As air flows into the compressor, energy is transferred from its
    rotating blades to the air. Pressure and temperature of the air
    increase.
   Most compressors operate in the range of 75% to 85% efficiency.


  Combustor
   The purpose of the combustor is to increase the energy stored in
    the compressor exhaust by raising its temperature.

  Turbine
   The turbine acts like the compressor in reverse with respect to
     energy transformation.
   Most turbines operate in the range of 80% to 90% efficiency.




  9
Principles of Operation
Overall Energy Transformations (Thermal Efficiency)


    Useful Work = Energy released in turbine minus energy absorbed by
     compressor.
    The compressor requires typically approximately 50% of the energy released by
    the turbine.
    Overall Thermal Efficiency =
     Useful Work/Fuel Chemical Energy *100
    Typical overall thermal efficiencies of a combustion turbine are 20% - 40%.




    10
Gas Turbine Applications


    Simple Cycle




                           Link to picture
    11
Simple Cycle Power Plant
Westinghouse 501D5 – 340 MW




 12
Combined Cycle Power Plant




 13
Combined Cycle Plant Design
        GT PRO 13.0 Drew Wozniak                                                                                                                                   Net Power 95959 kW
                                                                                                                                                                   LHV Heat Rate 7705 BTU/kWh
      12.54 p
      90 T                                                                    1X GE 6581B                                  967.3 m                     2 X GT                                 73.85 %N2
      30 %RH                                                                                                                                                                                  13.53 %O2
                                                                                                                                                       12.93 p
      944 m                                                                                                                                                                                   3.233 %CO2+SO2
                                                                           149.2 p                   143.2 p                                           1034 T                                 8.497 %H2O
      4327 ft elev.               Fogger                                                                                        33781 kW               1934.6 M
                                  4.717 m                                  684 T                     2072 T                                                                                   0.8894 %Ar

                                    12.39 p
                                    68 T
                                    948.7 m

                                                                                                                                                                                                                 30813 kW

                                                  Natural gas 18.58 m
                                                  LHV 369671 kBTU/h                                                                                 850 p
      122 T                                       77 T                     96 T                                                                     950 T
      292.6 M                                                                                                                                       248.6 M

           122 T        17.19 p                                                                                                                                                                                 1.694 p
                        220 T                                                                                                                                                                                   120 T
                                                                                                                                                                                                                222.1 M
                      29.58 M
                      29.65 M
                      292.6 M




                                                                                                                                                                                                          0.1296 M
                                                                                                                                                                       26.36 M




                                                                                                                                                                                                195.8 p 597 T
                                                                                                                                                                            879.8 p 954 T
                                                              183 p 375 T 70 M                                                       V4
                                                                                                                                                          6.89 M                                                120 T

                                                                                                                                                              V8


                                                                        6.89 M

                                                                                                                                                                                                                        FW




                                            LPB                  IPE2                   IPB         HPE2       IPS1      HPE3      IPS2      HPB1                                           HPS3

 268 T                                                                                                                                                                                                            1031 T
 1934.6 M                                                                                                                                                                                                         1934.6 M
                                            17.19 p              203.6 p                203.6 p 924.2 p        199.7 p 910.5 p     195.8 p 910.5 p                                          879.8 p
                                            220 T                373 T                  383 T 472 T            460 T 523 T         500 T 533 T                                              954 T
                                            29.65 M              292.6 M                36.75 M 251.1 M        36.75 M 251.1 M     36.75 M 248.6 M                                          248.6 M
                                      268                  326                    419         481       534        538      568        569                                  897                     1031
        p[psia], T[F], M[kpph], Steam Properties: Thermoflow - STQUIK                                                                                                                                           Natural gas
                                                                                                                                                                                                                0M
        1512 10-13-2004 23:27:31 file=C:\Tflow13\MYFILES\3P 0 70.gtp
 14
        Gas Turbine Components
     Compressor – Combustor - Turbine




15
    Gas Turbine Components & Systems (cont’d)
    Combustion System                    Exhaust System
            Silo, Cannular, Annular          Simple Cycle Stack
            Water, Steam, DLN                Transition to HRSG
    Turbine                              Generator
            Multiple Shaft, Single           Open-Air cooled
             Shaft                            TEWAC
            Number of Stages                 Hydrogen Cooled
            Material and                 Starting Systems
             Manufacturing                    Diesel
             Processes                        Motor
                                              Static
                                                         Paper Towel thru
                                                           compressor

    16
Combustion Turbine Fuels

     Conventional Fuels
         Natural Gas
         Liquid Fuel Oil
     Nonconventional Fuels
         Crude Oil
         Refinery Gas
         Propane
     Synthetic Fuels
         Chemical Process
         Physical Process


 17
GE Combustion Turbine Comparisons




 18
Gas Turbine Types
    Advanced Heavy-Duty Units
    Advanced Aeroderivative Units


    Parameter                   Heavy Duty Aero-Derivative
    Capital Cost, $/kW             Lower         Higher

    Capacity, MW                  10 - 330       5 – 100

    Efficiency                     Lower         Higher

    Plan Area Size                 Larger        Smaller

    Maintenance Requirements       Lower         Higher

    Technological Development      Lower         Higher


     19
Gas Turbine Major Sections

    Air Inlet
    Compressor
    Combustion System
    Turbine
    Exhaust
    Support Systems




    20
Gas Turbine Barrier Inlet Filter Systems




 21
Gas Turbine Pulse Inlet Filter System




 22
Inlet Guide Vanes




 23
Inlet Guide Vanes




 24
Gas Turbine Compressor Rotor Assembly




 25
6B Gas Turbine




 26
Gas Turbine Cut Away Side View




 27
Gas Turbine Combustor Arrangement




 28
Frame 5 GT




 29
GE LM2500 Aeroderivative Gas Turbine
                                   Power
                      Compressor
                                   Turbine
                        Turbine
                                   Section
                        Section
      Compressor




 30
FT4 Gas Turbine




 31
FT4 Gas Turbine – Gas Generator (Compressor)




 32
FT4 Gas Turbine – Gas Generator (Compressor)




 33
FT4 Gas Turbine – Free Turbine




 34
FT4 Gas Turbine – Free Turbine Gas Path




 35
FT4 Gas Generator Performance




 36
FT4 Free Turbine Performance




 37
Aeroderivative Versus Heavy Duty Combustion
Turbines
    Aeroderivatives
            Higher Pressure Ratios and Firing Temperatures Result
             in Higher Power Output per Pound of Air Flow
            Smaller Chilling/Cooling Systems Required
            Compressor Inlet Temperature Has a Greater Impact on
             Output and Heat Rate
            Benefits of Chilling/Cooling Systems are More
             Pronounced




    38
Typical Simple Cycle CT Plant Components

     Prime Mover (Combustion Turbine)
     Fuel Supply & Preparation
     Emissions Control Equipment
     Generator
     Electrical Switchgear
     Generator Step Up Transformer
     Starting System (Combustion Turbines)
     Auxiliary Cooling
     Fire Protection
     Lubrication System


 39
Typical Peaking Plant Components




      Lube Oil System         GSU            Generator




      Switchgear / MCC   Starting Engine   Fire Protection
 40
Combining the Brayton and Rankine Cycles

 Gas Turbine Exhaust used as the heat source for the Steam
  Turbine cycle
 Utilizes the major efficiency loss from the Brayton cycle
 Advantages:
            Relatively short cycle to design, construct & commission
            Higher overall efficiency
            Good cycling capabilities
            Fast starting and loading
            Lower installed costs
            No issues with ash disposal or coal storage
    Disadvantages
            High fuel costs
            Uncertain long term fuel source
            Output dependent on ambient temperature
    41
How does a Combined Cycle Plant Work?




 Picture courtesy of Nooter/Eriksen
   42
Combined Cycle Heat Balance




 43
Combined Cycles Today
     Plant Efficiency ~ 58-60 percent
          Biggest losses are mechanical input to the compressor and heat in the
           exhaust
     Steam Turbine output
          Typically 50% of the gas turbine output
          More with duct-firing
     Net Plant Output (Using Frame size gas turbines)
          up to 750 MW for 3 on 1 configuration
          Up to 520 MW for 2 on 1 configuration
     Construction time about 24 months
     Engineering time 80k to 130k labor hours
     Engineering duration about 12 months
     Capital Cost ($900-$1100/kW)
     Two (2) versus Three (3) Pressure Designs
          Larger capacity units utilize the additional drums to gain efficiency at
           the expense of higher capital costs

 44
Combined Cycle Efficiency
    Simple cycle efficiency (max ~ 44%*)
    Combined cycle efficiency (max ~58-60%*)
    Correlating Efficiency to Heat Rate (British Units)
            h= 3412/(Heat Rate)   --> 3412/h = Heat Rate*
            Simple cycle          – 3412/.44 = 7,757 Btu/Kwh*
            Combined cycle        – 3412/.58 = 5,884 Btu/Kwh*
    Correlating Efficiency to Heat Rate (SI Units)
            h= 3600/(Heat Rate)   --> 3600/h = Heat Rate*
            Simple cycle          – 3600/.44 = 8,182 KJ/Kwh*
            Combined cycle        – 3600/.58 = 6,207 KJ/Kwh*
    Practical Values
            HHV basis, net output basis
            Simple cycle 7FA (new and clean)      10,860 Btu/Kwh (11,457 KJ/Kwh)
            Combined cycle 2x1 7FA (new and clean) 6,218 Btu/Kwh (6,560 KJ/Kwh)

                                                                 *Gross LHV basis
    45
Gas Turbine Generator Performance

Factors that Influence Performance
         Fuel Type, Composition, and Heating Value
         Load (Base, Peak, or Part)
         Compressor Inlet Temperature
         Atmospheric Pressure
         Inlet Pressure Drop
              Varies significantly with types of air cleaning/cooling
         Exhaust Pressure Drop
              Affected by addition of HRSG, SCR, CO catalysts
         Steam or Water Injection Rate
              Used for either power augmentation or NOx control
         Relative Humidity
 46
Altitude Correction




 47
Humidity Correction




 48
Cogeneration Plant

     A Cogeneration Plant
         Power generation facility that also provides
          thermal energy (steam) to a thermal host.
     Typical thermal hosts
         paper mills,
         chemical plants,
         refineries, etc…
         potentially any user that uses large quantities of
          steam on a continuous basis.
     Good applications for combined cycle plants
         Require both steam and electrical power


 49
Major Combined Cycle Plant Equipment


     Combustion Turbine (CT/CTG)
     Steam Generator (Boiler/HRSG)
     Steam Turbine (ST/STG)
     Heat Rejection Equipment
     Air Quality Control System (AQCS) Equipment
     Electrical Equipment




 50
Heat Recovery Steam Generator (HRSG)




  51
Steam Turbine


      GE D11




 52
 Heat Rejection Equipment - Condenser

Same Function as
  discussed earlier in
  Session 9
      Usually utilizes a
       cooling tower to
       reject heat to the
       atmosphere
      Rarely uses once
       through cooling
       (retrofit applications
       or ocean)



  53
     Questions?




                          Rob Shepard
                        Neel-Schaffer, Inc.
                     www.Neel-Schaffer.com
                  rob.shepard@neel-schaffer.com

54

								
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