A steam plant operates on Rankine Cycle with two adiabatic turbine stages and a reheater. The...

 

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A steam plant operates on Rankine Cycle with two adiabatic turbine stages and a reheater. The boiler produces superheated steam at 100 bar and 400 °C with a heat input of 7 MW. The steam undergoes expansion within the first turbine stage and enters the reheater as dry saturated steam at 15 bar. Then, the reheater raises the steam temperature to 400 °C and feeds steam to the second turbine stage. The steam expands within the second turbine stage and exhausts to the condenser as dry saturated steam at 0.05 bar. The condensate leaves the condenser as saturated water, which is pumped back to the boiler by a feed pump with negligible work input. (a) Sketch the configuration of the steam plant. Draw the T-s diagram for the plant cycle, indicating all relevant state points. (b) Calculate the enthalpy of steam/water at each state point identified in Part (a). (c) Find the steam plant's mass flow rate and the power output of each turbine stage. (d) Determine the overall thermal efficiency of the plant. (e) Show that the two turbine stages are irreversible. A steam plant operates on Rankine Cycle with two adiabatic turbine stages and a reheater. The boiler produces superheated steam at 100 bar and 400 °C with a heat input of 7 MW. The steam undergoes expansion within the first turbine stage and enters the reheater as dry saturated steam at 15 bar. Then, the reheater raises the steam temperature to 400 °C and feeds steam to the second turbine stage. The steam expands within the second turbine stage and exhausts to the condenser as dry saturated steam at 0.05 bar. The condensate leaves the condenser as saturated water, which is pumped back to the boiler by a feed pump with negligible work input. (a) Sketch the configuration of the steam plant. Draw the T-s diagram for the plant cycle, indicating all relevant state points. (b) Calculate the enthalpy of steam/water at each state point identified in Part (a). (c) Find the steam plant's mass flow rate and the power output of each turbine stage. (d) Determine the overall thermal efficiency of the plant. (e) Show that the two turbine stages are irreversible.