Transcript MCB TOWER, Karachi - :: Ainul Abedin Consulting Engineers

11TH HVACR CONFERENCE, KARACHI,
MARCH 25-27,2004
CONDITIONING OF GAS TURBINE INLET AIR BY
ABSORPTION REFRIGERATION TO REDUCE
COSTS OF COMBINED CYCLE POWER PLANTS
AUTHOR:
AINUL ABEDIN, P.E.
FELLOW ASHRAE, FELLOW I.E. (PAK)
AINUL ABEDIN CONSULTING ENGINEERS
KARACHI
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COMBINED CYCLE POWER PLANT
PERFORMANCE
•
Most Efficient Thermal Power Plants.
•
GT Performance Affected By Air Mass Flow.
•
Lowering of Air Density Both Due to Higher Altitude
(Site Specific) & Increase in Ambient Temperature.
•
1 % Capacity
Temperature.
•
1 % Decrease in Efficiency For Each 3 deg.C Rise in
Temperature.
Loss
For Each 1
deg.C
Rise in
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EFFECT OF GT COMPRESSOR INLET
TEMPERATURE ON OUTPUT & HEAT
RATE
Percent Design
Effe ct of G.T. Compre ssor Inle t
Te mpe rature on Output & He at Rate
120
100
80
Heat Rate
60
40
20
0
Output
5
10
15
20
25
30
35
40
45
G.T. Comperessor Inlet Temperature
(Deg. C)
Figure 1
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COMBINED CYCLE POWER PLANT
COSTS
• Capital Costs US $ 600-700 / kW Capacity (ISO
Rating).
• At Peak Summer (45 deg.C), Actual Capacity Could
Cost 30 % Higher Per kW Due to Power Plant De-rating.
• Inefficient Operation at High Ambients also Increase
Specific Fuel Consumption.
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CONDITIONING OF GT INLET AIR BY
REFRIGERATION
• Cooling & Controlling Humidity of GT Inlet Air to ISO
Conditions For Full Combined Cycle Power Plant
Capacity, Increase Upto 30 % from De-rated Capacity
at 45 deg.C.
• Operation at ISO Conditions Will Result in Lower Heat
Rate, Not Only For Additional Capacity But For Total
Generation And This Would Result in Very Big Fuel
Savings
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GAS TURBINE-BASED COMBINED
CYCLE STATION LAYOUT
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INTEGRATED SYSTEM DESIGN FOR GT
INLET CONDITIONING WITH
ABSORPTION REFRIGERATION
• For Economical Refrigeration, Proposed Design is Based
on Utilisation of Waste Heat Availability From Steam
Turbine Extraction.
• Actual Cost of Energy For Absorption Refrigeration is
Reduced Due to Maximum Utilisation of Steam Enthalpy
(Over 75 %) For Power Generation in Steam Turbine
before Extraction at 15 psig.
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INTEGRATED SYSTEM DESIGN
(CONTD)
• Single-stage Low-cost Absorption Chillers Have Very
Reliable Operation History in Pakistan.
• Since There Are No Moving Equipment (Only Small
Pumps), Simple Service & Maintenance Required For
Absorption Chillers.
• Cooling Water Circuit of Condensing Steam Turbine Can
Be Combined With Absorption Chiller Condenser Water
Circuit For Most Economical Integrated Combined Cycle
Power Plant Design.
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REFRIGERATION CAPACITY FOR GT
INLET CONDITIONING
• For Efficient Gas Turbines, Capacity Increase of 30 %
(To Cool Inlet Air From 45 deg.C To 15 deg.C) Requires
About 44 Tons of Cooling For Each 1 MW ISO Capacity.
• Modern Efficient 300 MW ISO Rated Combined Cycle
Power Plant Would Require Peak 8,800 Tons of
Refrigeration to Increase De-rated Capacity at 45
deg.C, to Full Capacity at 15 deg.C This Would be
Required During Full-load Operation, Normally 8-10
Hrs/Day.
• With Thermal Storage System, On-line Absorption
Refrigeration of About 3,000 Tons Capacity Would
Ensure Both Enhanced Capacity & Efficiency During Full
Load Operation.
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COMBINED CYCLE POWER STATION
PART-LOAD OPERATION WITH
CONDITIONING OF GT INLET AIR
• Since Cooling Coil is Redundant During Part-load
Operation, Additional GT Inlet Pressure Drop Increases
Heat Rate Due to Lower Efficiency.
• GT Inlet Air Heating Could Be Utilised To Increase
Overall Cogeneration Efficiency Since Normally, Most
Base-load Combined Cycle Power Stations Operate at
Part-load For Long Duration (14 – 16 Hours) Every
Day.
• Integrated System Design Allows Use of Components of
GT Inlet Cooling for Economical Inlet Heating Cycle.
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WORLD WIDE APPLICATIONS OF GAS
TURBINE INLET COOLING BY
REFRIGERATION
• In USA, Over 350,000 Tons of Refrigeration Have Been
Installed For Enhancement of Gas Turbine-Based Power
Plant Capacity.
• In Brazil (With Conditions Similar To Pakistan), Nearly
53,000 Tons of Refrigeration Have Been Installed in
Similar Power Plants.
• Large Installation in Saudi Arabia Also.
• Pakistan Has Only Small Gas Turbine Power Plants’
Installation With Inlet Air Cooling But These Examples
Prove Performance & Available Technology.
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