the simple rankine cycle power plant operates on steam between 8kpa and 4 mpa .
What is the Simple Rankine Cycle?
Answer: The Simple Rankine Cycle is a thermodynamic cycle used to generate electricity in power plants, typically utilizing steam as a working fluid. It consists of four key components:
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Boiler: Water is heated to form steam at high pressure, typically at 4 MPa (megapascals).
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Turbine: The high-pressure steam expands through a turbine, producing mechanical work. The typical low pressure after expansion might be 8 kPa (kilopascals).
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Condenser: The steam exits the turbine and is cooled in the condenser where it returns to a liquid state.
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Pump: The liquid water is pumped back to the boiler, increasing its pressure to start the cycle again.
Cycle Process:
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Isentropic Expansion in the Turbine:
- High-pressure steam expands and does work on the turbine blades, decreasing pressure and temperature.
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Heat Rejection in the Condenser:
- The exhaust steam from the turbine is condensed to water at constant pressure, typically at 8 kPa. Heat is rejected to the cooling environment.
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Isentropic Compression in the Pump:
- The condensed water is pumped back to boiler pressure, increasing its pressure and temperature without significant change in entropy.
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Heat Addition in the Boiler:
- The high-pressure water absorbs heat and turns into steam at 4 MPa.
Thermal Efficiency:
The thermal efficiency ((\eta)) of the Rankine cycle is determined by the ratio of net work output to heat input, which is a crucial factor for power plants.
Why These Pressures?
- High Pressure (4 MPa): Increases the efficiency by maximizing the energy extracted by the turbine.
- Low Pressure (8 kPa): Lowers the temperature in the condenser, enabling more heat extraction and improving efficiency.
Summary: The Simple Rankine Cycle generates power by converting water to steam and back. It operates between a high-pressure boiler and a low-pressure condenser, with pressures like 4 MPa and 8 kPa to optimize efficiency and energy production.