Page 119 - Handbook of Energy Engineering Calculations
P. 119
the extraction flow rate, Q = 20,000 lb /h (150 kg/s); other values as before.
x
m
6
Then, AE = (80,000 − 20,000)(1284 − 1225) = 3.54 × 10 Btu/h (1037 kJ/s).
2
6
Total available energy to the turbine, AE = AE + AE = 6.296 × 10 + (3.54
2
1
6
6
3
× 10 ) = 9.836 × 10 Btu/h (172.8 × 10 kJ/s).
3. Compute the turbine’s kW output
The power available to the turbine to develop power at the shaft, in kilowatts,
6
kW = AE/(Btu/kW · h) = 9.836 × 10 /3412.7 = 2880 kW. However, the actual
power developed at the shaft, kW = kW × e, where e is the mechanical
a
efficiency of the turbine. Thus, for an efficiency, e = 0.90, then kW = 2880 ×
a
0.90 = 2590 kW (2590 kJ/s).
Related Calculations. The Steam Tables appear in Thermodynamic
Properties of Water Including Vapor, Liquid, and Solid Phases, 1969,
Keenan, et al., John Wiley & Sons, Inc. Use later versions of such tables
whenever available, as necessary.
