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 °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° 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 Page 1 of 2 B 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°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 Page 2 of 2 B