Steam leaves the boiler of a power plant at 5 MPa, 500°C as shown in Figure P3.22. As the steam passes to the turbine, the temperature drops to 496°C before it enters the turbine due to a heat loss through the pipe’s insulation. The pressure drop in the pipe connecting the boiler to the turbine is negligible. The steam then passes through an adiabatic turbine and exits at 10 kPa. The turbine has an isentropic efficiency of 85% and is delivering 1000 MW of power.
Determine the following,

a. The heat transfer rate from the pipe connecting the boiler to the turbine (in MW)

b. The change in flow exergy rate as the steam flows through the pipe (MW). This represents exergy that is lost to the environment and unavailable for power delivery. Comment on the magnitude of this exergy loss compared to the power delivered by the turbine. What factor(s) would warrant better insulation on the pipe to reduce this exergy loss?

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Boiler P = 5 MPa T = 500C FIGURE P3.22 Boiler and turbine of a steam power plant. P = 1 atm T = 25C P = 5 MPa T = 496C 2 17, = 85% Turbine W, = 1,000 MW 3+ P =10 kPa