Problem 6.29:

The steam power plant shown in Figure 6-18 uses a two-stage turbine and one feedwater heater that regenerates the partly exhausted steam from the first turbine stage. The steam enters the turbine at 60 bar and 700 °C, and exhausts at 1 bar. Steam for the feedwater heater is extracted from the turbine at 5 bar and exits the heater as saturated liquid (stream 7), while stream 1 exits at a temperature that is 6 °C below that of stream 7. The condenser produces saturated liquid. Calculate the energy balances, the thermodynamic efficiency, and perform an entropy analysis around each unit of the process. What are the advantages of this design compared to the simple Rankine plant? Additional data: The efficiency of both stages in the turbine and of the pump is 80%.