Download - Presentacion air inlet cooling system
PB Power
Gas Turbine Inlet Air Cooling System
The 3rd Annual Australian Gas Turbine Conference
6th – 7th December 2001MelbourneAustralia
Presented by
Bob OmidvarManager, Power Engineering
PB Power Australia
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75%
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105%
110%
0 5 10 15 20 25 30 35 40 45GT Inlet Temp (deg C)
Heat rate kJ/kWh Power output MW Exhaust flow t/h Exhaust temperature °C
Heavy Duty GT - Effects of Ambient Temp
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60%
70%
80%
90%
100%
110%
120%
0 5 10 15 20 25 30 35 40 45
GT Inlet Temp (deg C)
Exhaust temperature C Heat rate kJ/kWh Power output MW Exhaust flow t/h
Aero-Derivative GT - Effects of Ambient Temp
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Gas Turbine Performance Design BasisWhat Does ISO Condition Mean?
! Dry bulb 15°C
! Relative humidity 60%
! Wet bulb temperature 7.2°C
! Atmospheric pressure 1 bar (sea level)
Most of the gas turbine installations are not in ISO standard locations, they are in the real world
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Ambient Air and Gas Turbine Performance
1. Air density is inversely related to the dry bulb temperature
2. Gas turbine output depends on mass flow and not the volume of air
3. Ambient temperature affects the following points drastically
" Air flow
" Output
" Heat rate
" Exhaust temperature
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Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
PB Power
Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
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Fuel
Combustion Turbine
Water Tank
CombustionAir
WettedMedia
Schematic of Evaporative Air Coolingshown with Optional Water Treatment
Exhaust GasBlow down
WaterTreatment
MakeUp
AirFilter
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Evaporative CoolerApplications: Areas where RH and wet bulb temperature is rather low
Advantage# Lowest capital cost
# Lowest O&M cost
# Can operate on raw water
# Quick delivery and installation time
# Operates as an air washer and cleans the inlet air
Disadvantage# Limitation on capacity
improvement
# Highly influenced by the site wet bulb
PB Power
Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
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Fuel
Combustion Turbine
DemineralisedWater Tank
CombustionAir
FogSpray
System
Schematic of Fog Inlet Air Cooling SystemUtilizing Demineralised Water
DemineralisedWater Treatment
Plant
RawWater
Exhaust Gas
AirFilter
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Fog Systems
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Demineralised Water Quality For Fog System Inlet Air Cooling
Total dissolved solids
pH
Na + K
5 PPM maximum
6-8
0.1 PPM maximum
Silica (SiO2)
Chlorides
Sulphate
0.1 PPM maximum
0.5 PPM maximum
0.5 PPM maximum
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0 25 50 75 100 125 150 175 200 225 250
Gas Turbine Output MW
t/h
Fogging System Demin. Water ConsumptionInlet air 36°C DB, 25°C WB
Chilled air temp 25.5°C DB 25°C WB, 96%RH
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Fogging SystemApplications: Areas where RH and wet bulb temperature is rather low
Advantage# Low capital cost
# Low O&M cost
# Can increase gas turbine performance better than evaporative cooling
# Quick delivery and installation time
Disadvantage# Limitation on capacity
improvement
# Highly influenced by the site wet bulb
PB Power
Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
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Fuel
Combustion Turbine
AmmoniaLiquid Line
MechanicalRefrigeration
Machine
CombustionAir
AmmoniaSuction Line
Schematic of a Direct SystemUsing an Ammonia Refrigeration Machine
Exhaust Gas
AirFilter
CondensateDrip Pan
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Mechanical Refrigeration System (Direct Type)Applications: Areas where relative humidity is rather high
Advantage# Can increase gas turbine
performance better than evaporative cooling, and fog system
Disadvantage# High initial capital cost
# High O&M cost
# Longer delivery and installation time
# Expertise is needed to operate and maintain the plant
PB Power
Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
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Fuel
Combustion Turbine
Chilled WaterPump
Mechanical Chiller
CombustionAir
Air CoolingCoil
Schematic of an Indirect SystemUsing a Mechanical Chiller
Exhaust Gas
AirFilter
CondensateDrip Pan
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Mechanical Refrigeration System (Indirect Type)Applications: Areas where relative humidity is rather high
Advantage# Can increase gas turbine
performance better than evaporative cooling, and fog system
# Not very sensitive to ambient air wet bulb temperature
Disadvantage# High initial capital cost# High O&M cost# Long delivery and installation
time# Expertise is needed to
operate and maintain the plant
# Requires extra chilled water cooling circuit
# Higher parasitic load than direct type
# Higher energy input compared to direct type chiller
PB Power
Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled
water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
PB Power
Fuel
Combustion Turbine
Chilled WaterPump
Mechanical Chiller/Ice Maker
CombustionAir
Air CoolingCoil
Inlet Air Cooling With Ice Storage,Chilled Water Storage System Schematic
Ice Storage Tank
Exhaust Gas
AirFilter
CondensateDrip Pan
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Fuel
Combustion Turbine
Chilled WaterPump
ChilledWater
StorageTank
Mech.Chiller
CombustionAir
Air CoolingCoil
Inlet Air Cooling With Chilled Water StorageSystem Schematic
Exhaust Gas
AirFilter
CondensateDrip Pan
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Mechanical Refrigeration SystemWith Ice Storage
Applications: Areas where RH is rather high,plus a wide variation in electricity tariff between peak and non peak hours
Advantage# Can increase gas turbine
performance better than evaporative cooling, and fog system
# Not very sensitive to ambient air wet bulb temperature
# Can utilise low night time tariff to produce and store ice for peak hours operation
Disadvantage# High initial capital cost# High O&M cost# Longer delivery and
installation time# Higher expertise is needed
to operate and maintain the plant
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0 25 50 75 100 125 150 175 200 225 250 275 300
Gas Turbine Output MW
Chi
ller E
lect
rical
Loa
d M
WChiller Electrical Load MW
36°C DB, 25°C WB, 10°C Chilled Air Temp
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Gas Turbine Inlet Air CoolingAvailable Technologies
1. Evaporative cooler2. Fogging system3. Mechanical refrigeration system (direct type)4. Mechanical refrigeration system (indirect type)5. Mechanical refrigeration with ice storage6. Mechanical refrigeration system with chilled water storage7. Single stage Lithium Bromide Absorption chiller8. Two stage Lithium Bromide Absorption chiller
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Fuel
Combustion Turbine
Chilled WaterPump
Absorption Chiller
CombustionAir
Air CoolingCoil
Absorption Chiller Inlet Air CoolingSystem Schematic
Heat RecoverySteam Generator
Exhaust Gas
AirFilter
CondensateDrip Pan
LP S
team
Ret
urn
Con
dens
ate
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6°C
12°C
Chilled Water
Tower Water In
Tower Water Out
Heat Medium Out
Heat Medium In Steam or Hot Water
tc 45°C
95°C
70°C
to 4°C
Condenser
Generator
Pressure approx.60 Torr60 mm Hg80 mbar8 kPa
Pressure approx.6,2 Torr6,2 mm Hg8,2 mbar0,83 kPa
ta 35°C
Evaporator
Absorber
50°C
70°C
27°C
32,5°C
37°C
Refrigerant (Water)Steam or Hot WaterDiluted Solution (LiBr)Concentrated Solution (LiBr)Tower WaterChilled Water
Flow Diagram
Picture courtesy of York International
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Gas Turbine Output MW
Stea
m C
onsu
mpt
ion
t/h
Single StageTwo Stage
Absorption Chiller Steam Consumption36°C DB, 25°C WB, 10°C Chilled Air Temp
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Single Stage Lithium Bromide Absorption ChillerApplications: Areas where relative humidity is rather high, and the plant is going to operate in a combined cycle or cogeneration mode and has
access to low pressure steamAdvantage# Can increase gas turbine
performance better than evaporative cooling, and fog system
# Not very sensitive to ambient air wet bulb temperature
# Low electrical parasitic load
Disadvantage# High initial capital cost# High O&M cost# Longer delivery and
installation time# High expertise is needed to
operate and maintain the plant
# In case of a steam operated chiller, cannot be applied in an open cycle gas turbine plant
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Two Stage Lithium Bromide Absorption ChillerApplications: Areas where relative humidity is rather high, and the plant is going to operate in a combined cycle or cogeneration mode and has
access to low pressure steamAdvantage# Can increase gas turbine
performance better than evaporative cooling, and fog system
# Not very sensitive to ambient air wet bulb temperature
# Low electrical parasitic load# Requires less steam per unit
of refrigeration than single stage chiller
Disadvantage# High initial capital cost# High O&M cost# Longer delivery and
installation time# High expertise is needed to
operate and maintain the plant
# In case of a steam operated chiller, cannot be applied in an open cycle gas turbine plant
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Gas Turbine Output MW
Con
dens
ate
Form
atio
n t/h
Condensate Formation on the Chilled Water Coil t/hBased on 36°C DB, 25°C WB, 10°C Chilled Inlet Air
Temperature
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Performance EvaluationOf Different Inlet Air Cooling Systems
Base Condition! 35°C Dry bulb! 25°C Dry bulb Real world condition! 44.7% Relative humidity
Increase in power output
Gas turbine output before inlet air cooling
Gas turbine output with mechanical refrigeration system and inlet air
temperature of 10°C
Gas turbine with evaporative cooler running at 85% RH
Gas turbine with fog system running at 100% RH
0%108.23 MW (net)
Percent Change
15.3%124.8 MW (net including chiller electrical load)
6%114.8 MW (net)
7.69%116.65 MW (net)
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Capital Cost Comparisons ofInlet Cooling Systems
Options
Evaporative cooler
Fog system (excluding water treatment plant)
Relative Costs
1
2Single stage LiBrabsorption chillerTwo stage LiBrabsorption chillerAmmonia mechanical refrigeration system
8
10
9.5
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Major Contributors To The O&M CostsOptionsEvaporative cooler
Fog system (excluding water treatment plant)
O&M Costs# Make up water# Water treatment (if applicable)# Make up water# Demineralised water treatment# Injection pump power consumption
Single stage LiBrabsorption chiller
Two stage LiBr absorption chiller
Ammonia mechanical refrigeration system
# Steam# Cooling tower chemical treatment# Chiller maintenance# Electric power consumption# Steam# Cooling tower chemical treatment and
make up water# Chiller maintenance# Electric power consumption# Electric power consumption# Cooling tower chemical treatment and
make up water# Chiller maintenance
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Heavy Duty Gas Turbine NOx Emission kg/MWhGT with Dry Low NOx burner
0.410
0.420
0.430
0.440
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0.470
0 5 10 15 20 25 30 35 40 45
Ambient Temperature deg C
NO
xEm
issi
on k
g/M
Wh
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Heavy Duty Gas Turbine CO2 Emission kg/MWh
520530
540550560570
580590
0 5 10 15 20 25 30 35 40 45
Ambient Temperature deg C
CO
2Em
issi
on k
g/M
Wh
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Aero-Derivative Gas Turbine NOx Emission kg/MWhGT with Dry Low NOx burner
0.37
0.38
0.39
0.4
0.41
0.42
0.43
0 5 10 15 20 25 30 35 40 45
Ambient Temperature deg C
NO
xEm
issi
on k
g/M
Wh
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Aero-Derivative Gas Turbine CO2 Emission kg/MWh
470
480
490
500
510
520
530
540
550
0 5 10 15 20 25 30 35 40 45
Ambient Temperature deg C
CO
2Em
issi
on k
g/M
Wh
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In Selecting Inlet Air Cooling As A Retrofit To An Existing Plant
Points to watch:! Check the generator capacity in order not to overload the
generator
! Quality of raw water for the evaporative cooler
! When using an existing demineralised water treatment plant, be careful about the capacity and quality of available demineralised water
! With an existing heat recovery steam generator, inlet air cooling will change the behaviour of the existing HRSG, leading to a drop in steam production at high pressure and increase in intermediate and low pressure steam