Class 4 Power Engineering Exam Prep – Part B (50 Questions)

Class 4 Power Engineering Exam Prep – Part B (50 Questions)

1. What is the primary function of a steam boiler?

To generate steam by applying heat energy to water.

2. What type of energy conversion occurs in a steam turbine?

Thermal energy of steam is converted into mechanical energy.

3. What is the function of a condenser in a steam cycle?

To condense exhaust steam back into water for reuse in the boiler.

4. What is the typical efficiency range of a steam turbine?

30% to 45%.

5. What is a deaerator used for?

To remove dissolved oxygen and gases from feedwater.

6. What does an economizer do in a boiler system?

Preheats feedwater using flue gas heat to improve efficiency.

7. What is superheated steam?

Steam that is heated above its saturation temperature at a given pressure.

8. Why is superheated steam used in turbines?

To prevent condensation and improve turbine efficiency.

9. What is the function of a boiler drum?

It separates steam from water and provides storage for steam generation.

10. What does a soot blower do?

Removes deposits from boiler tubes to improve heat transfer.

11. What is cavitation in pumps?

The formation and collapse of vapor bubbles causing damage and loss of efficiency.

12. What is the purpose of a gland sealing system on a steam turbine?

To prevent steam leakage and air ingress at the turbine shaft.

13. What is a draft in boiler operation?

The flow of air and flue gases through the boiler system.

14. What are two main types of boiler draft?

Natural draft and mechanical draft.

15. What is the function of an induced draft fan?

Draws flue gases out of the boiler and maintains furnace pressure.

16. What is the function of a forced draft fan?

Supplies combustion air into the furnace.

17. What is the difference between a fire-tube boiler and a water-tube boiler?

Fire-tube: hot gases pass through tubes surrounded by water.
Water-tube: water passes through tubes heated by combustion gases.

18. Which type of boiler is more efficient for high pressure applications?

Water-tube boiler.

19. What is the function of a steam trap?

Removes condensate from steam lines without losing steam.

20. What are three main types of steam traps?

Thermostatic, mechanical (float), and thermodynamic.

21. What is the primary purpose of boiler water treatment?

To prevent scale, corrosion, and carryover.

22. What is scale in boilers caused by?

Deposition of dissolved minerals such as calcium and magnesium.

23. What is boiler carryover?

Water droplets carried with steam, reducing efficiency and causing damage.

24. How is pH typically controlled in boiler water?

By adding alkalinity agents such as sodium hydroxide or phosphate treatment.

25. What is blowdown in a boiler?

The removal of concentrated boiler water to control dissolved solids.

26. What are the two types of boiler blowdown?

Continuous blowdown and intermittent (bottom) blowdown.

27. What is the purpose of turbine governing?

To regulate turbine speed and load.

28. What does “enthalpy” measure in steam?

Total heat content (sensible + latent + superheat).

29. What is a heat exchanger used for?

Transfers heat between two fluids without mixing them.

30. What is a common type of feedwater heater?

Shell-and-tube heat exchanger.

31. What does a pressure reducing valve do?

Lowers steam pressure to required levels for equipment use.

32. What is a boiler refractory?

Heat-resistant material lining the furnace to protect metal and conserve heat.

33. What is the function of a steam separator?

Removes entrained water droplets from steam.

34. What is a turbine overspeed trip?

A protective device that shuts down the turbine if speed exceeds safe limits.

35. What is the difference between saturated and superheated steam?

Saturated steam is at boiling point, while superheated steam is above saturation temperature.

36. What is a steam accumulator?

A pressure vessel that stores steam for sudden load demands.

37. What does a governor valve do in a turbine?

Regulates steam flow to control turbine speed and power output.

38. What is a surface condenser?

Condenses steam by passing it over tubes cooled by circulating water.

39. What is the function of gland steam condenser?

Condenses steam leaking past turbine shaft seals.

40. What is boiler efficiency?

The ratio of heat energy absorbed by steam to the heat energy supplied by fuel.

41. What is a feedwater regulator?

Controls the flow of feedwater into a boiler to maintain water level.

42. What is priming in boilers?

Carryover of water droplets with steam due to high water level or impurities.

43. What is foaming in boilers?

Formation of stable bubbles that cause water carryover with steam.

44. What is a turbine reheater?

Reheats steam after partial expansion to improve efficiency.

45. What is the function of a condenser vacuum pump?

Removes non-condensable gases to maintain condenser vacuum.

46. What is meant by boiler “dry firing”?

Operating a boiler without water, which can cause catastrophic damage.

47. What is the function of an air preheater?

Heats combustion air using flue gases to improve efficiency.

48. What does a boiler safety valve do?

Releases steam automatically if pressure exceeds safe limits.

49. What is meant by boiler “turn down ratio”?

The ratio of maximum to minimum firing rate of the burner.

50. Why is feedwater heating important in power plants?

It improves efficiency by reducing thermal shock and increasing boiler temperature.

UK

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