Quiz One Solution - 14

```Power Plant Quiz One
Name: ________________________________ Class No:________ Reg No: _________________
1. Steam enters the turbine of a vapor power plant at 1600 lbf/in.2, 1000oF and exits as
a two-phase mixture at 1 lbf/in.2. The quality of steam at exit is
a. 0.825
c. 0.812
b. 0.925
d. 0.912
2. In question 1, if turbine efficiency is 88%, the exit enthalpy at the condenser is:
a. 912 Btu/lbm
b. 1547 Btu/lbm
c. 988 Btu/lbm
d. 1655 Btu/lbm
3. In an Ideal Rankine Cycle, the pump operates at constant ___________
a. Pressure
c. Specific Entropy
b. Specific Enthalpy
d. Both a and b
4. In an Ideal Rankine Cycle, the condenser operates at constant ___________
a. Pressure
c. Specific Entropy
b. Specific Enthalpy
d. Specific Internal Energy
5. For acceptable moisture content we aim for at least 90% quality for the __________
outlet.
a. Turbine
c. Pump
b. Condenser
d. None of the above
6. Steam at 18 MPa, 560 &deg;C is expended to 6 kPa. The final entropy of the steam is:
a. 8.33 kJ/kg.K
c. 7.44 kJ/kg.K
b. 7.33 kJ/kg.K
d. 6.44 kJ/kg.K
7. In question 6, if turbine efficiency is 88%, the exit enthalpy at the condenser is::
a. 1520 kJ/kg
c. 1982 kJ/kg
b. 2567 kJ/kg
a. 2245 kJ/kg
8. The specific enthalpy of wet steam at pressure of 70 kN/m2 and having dryness
fraction of 0.85:
a. 2660.1 kJ/kg
c. 2600.3 kJ/kg
b. 2321.8 kJ/kg
d. 2545.9 kJ/kg
9. Steam at 4 MN/m2 and dryness fraction 0.95 receives heat at constant pressure until
its temperature becomes 350&deg; C. The heat received by the steam per kilogram is:
a. 3095 kJ/kg
c. 501.0 kJ/kg
b. 380.3 kJ/kg
d. 3215.7 kJ/kg
10. The specific volume of water at saturation temperature for a pressure of 4.0 MN/m2:
a. 0.001084 m3/kg
c. 0.001252 m3/kg
b. 0.46220 m3/kg
a. 0.049749 m3/kg
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Power Plant Quiz One
Name: ________________________________ Class No:________ Reg No: _________________
11. In a turbine the enthalpy of steam entering is 2500 kJ/kg. The turbine power output is
1000 MW and steam flow rate is 1000 kg/sec. The enthalpy of steam leaving the
turbine is:
a. 3500
c. 1500
b. 2500
d. 500
12. An adiabatic steam turbine has an efficiency of 80% and it produces work output of
1000 kJ/kg, The maximum input is (in kJ/kg):
a. 800
c. 1250
b. 1000
d. 1500
13. Steam turbine had exit pressure of 10 kPa. The enthalpy at inlet is 3000 kJ/kg and
work output is 1000 kJ/kg. The quality of steam is:
a. 0.95
c. 0.85
b. 0.75
d. Not defined
14. A pump used in Rankine cycle has flow rate of 100 kg/s. It pump liquid water, with v
= 0.001 m3/kg from pressure of 10 kPa to 10 MPa. If efficiency of pump is 80%, the
magnitude of pumping power is
a. 4250 kJ/s
c. 2250 kJ/s
b. 3250 kJ/s
d. 1250 kJ/s
15. A simple Rankine cycle operates the boiler at 10 MPa with an outlet temperature of
480&deg;C and the condenser at 6 kPa. Assuming ideal operation and processes, what is
the thermal efficiency of this cycle?
a. 7.2 %
c. 37.2 %
b. 17.2 %
d. 41.2 %
16. The energy rejected by heat transfer to the cooling water in open feedwater heater is
a. Reduced
c. Remain same
b. Increased
d. None of above
17. A coal-fired power-plant generate 1000 MW gross, by using 9800 tons of coal per
day. If heating value of coal is 11,500 Btu/lbm. The rate of coal burned is:
a. 816,667 lbm/h
c. 139,323 lbm/h
b. 403.333 lbm/h
d. None of the above
18. Supercritical power plants use pressure above
a. 3200 psia
c. Critical Pressure
b. 2500 psia
d. Superheat Pressure
19. The Heat Rate (HR) is ____________ proportional to efficiency
a. Directly proportional to efficiency
c. Directly proportional to fuel
b. Inversely proportional to efficiency
consumption
d. Both b and c
20. A binary vapor cycle use _____________
a. Ammonia as working fluid
c. Does not have condenser
b. Two vapor cycle
d. Both b and c
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