Repeat Problem 8.42, retaining all quantities except that each reheater reheats the steam back to 600°C, that is, T9 = T11 = 600°C.
The T-s diagram of an ideal Rankine power cycle with two reheat cycles and two open feedwater heaters is shown in Fig. 8.39. Steam leaves the boiler at state 7 at 15 MPa and 600°C. Steam at 4 MPa leaves the high-pressure turbine at state 8; some of the steam preheats water in feedwater heater #1 from state 4 to state 5, while the remainder is reheated to 500°C at state 9. Steam at 600 kPa is extracted from the low-pressure turbine at state 10; some of that steam preheats water in feedwater heater #2 from state 2 to state 3, while the remainder is reheated to 400 8 C at state 11. Steam at 10 kPa leaves the low-pressure turbine at state 12. For a mass flux m · = 20 kg/s through the boiler, calculate:
i) The steam flow rate diverted to each feedwater heater
ii) The power output of the turbine
iii) The total heat addition by the steam generator
iv) The quality of the steam exiting the turbine
v) The heat loss from the condenser
vi) The total pump horsepower
vii) The thermodynamic efficiency of the cycle
Figure 8.39

10 12 m10