Impact of Cycle Design on Steam Generator

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Impact of Cycle Design on Steam Generator

• P M V Subbarao
• Professor
• Mechanical Engineering Department

The strongest Measures of Development.
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Basic The Theme Steam Generator Design

• Constrains
• Imposed by Cycle Design (pmax, Tmax, etc.)
• Fuel Combustion Related.
• Heat Transfer Related
• Safety and Reliability Related.

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The Basic Rankine Cycle
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Gas to Liquid Heat Exchange
Liquid Heating
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The Power Gods
1760 James Watt
1820 Sadi Carnot
George Brayton W Rankine 1860
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Law of Power Generation
Coal (Source)
Power Plant --Cycle Design -- Equipment
Design --Equipment Operation
Land, Water Air (Sinks)
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Progress in Rankine Cycle
Year 1907 1919 1938 1950 1958 1959 1966 1973 1975
MW 5 20 30 60 120 200 500 660 1300
p,MPa 1.3 1.4 4.1 6.2 10.3 16.2 15.9 15.9 24.1
Th oC 260 316 454 482 538 566 566 565 538
Tr oC -- -- -- -- 538 538 566 565 538
FHW -- 2 3 4 6 6 7 8 8
Pc,kPa 13.5 5.1 4.5 3.4 3.7 3.7 4.4 5.4 5.1
h, -- 17 27.6 30.5 35.6 37.5 39.8 39.5 40
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Role of SG in Rankine Cycle
Perform Using Natural resources of energy .
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Impact of cycle on Construction of Steam Generator
Economizer
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Trends in coal-fired generation Performance

• The average efficiency of coal-fired generation
  is projected to increase from 34 in 2006 to 36
  in 2015 and to 38 in 2030.
• In the OECD, efficiency increases from 37 to
  41.
• In non-OECD countries, efficiency improves from
  31 to 37 because new coal-fired power plants
  built to meet rapidly growing electricity demand
  are expected to be far more efficient than
  existing ones.

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Modern Measure of Performance
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The Rankine Cycle
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Pump Isentropic Process
1
2
SSSF Conservation of mass
First Law
No heat transfer, change in kinetic and potential
energies are negligible
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2 3 SG Isobaric Heating p3 p2
QCV
3
2

• No work transfer, change in kinetic and potential
  energies are negligible

Assuming a single fluid entering and leaving
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Constant Pressure Heating Process
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Constant Pressure Heating Process
Vapour
Liquid Vapour
h
Liquid
s
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Ideal Rankine Cycle
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Constant Pressure Heating Process
s