In a steam power plant, superheated steam at 9 MPa and 500°C, is expanded isentropically in a turbine until it becomes a saturated vapor. It is then reheated at constant pressure to 500°C. The steam is next expanded isentropically in another turbine until it reaches the condenser pressure of 15 kPa. Relevant properties of steam are given in the following two tables. The specific steam consumption rate will be ____ kg/kW-hr. (round off to the nearest integer). Neglect the pump work consumption.
For superheated water:
|
p (MPa) |
Temperature, T (°C) |
Enthalpy, h (kJ/kg) |
Entropy, s (kJ/kg.K) |
|
9 |
500 |
3387.4 |
6.6603 |
|
0.8 |
500 |
3481.3 |
7.8692 |
For saturated Steam Table:
|
Pressure, p |
Sat. Temp, Tsat (°C) |
Enthalpy, h (kJ/kg) |
Entropy, s (kJ/kg.K) |
||
|
hf |
hg |
sf |
sg |
||
|
0.8 MPa |
170.41 |
2047.5 |
2768.3 |
2.0457 |
6.6603 |
|
15 kPa |
53.97 |
225.94 |
2598.3 |
0.7549 |
8.0071 |
Enter numerical value using the virtual keypad. Round off where necessary.