1st Class Power Engineer A2 Exam Questions
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. In a high-pressure water-tube boiler, the primary purpose of the
economizer is to:
• A. Increase furnace draft
• B. Cool flue gases below the dew point
• C. Preheat feedwater using waste heat from flue gases
• D. Superheat steam
Rationale: An economizer improves boiler efficiency by recovering
heat from outgoing flue gases and transferring it to incoming
feedwater. This reduces fuel consumption, minimizes thermal shock to
the boiler, and increases overall plant efficiency.
2. The critical pressure of water is approximately:
• A. 10 MPa
, • B. 16 MPa
• C. 22.1 MPa
• D. 35 MPa
Rationale: The critical pressure of water is approximately 22.1 MPa
(3,206 psi). Above this pressure, water and steam become
indistinguishable, eliminating the latent heat of vaporization.
3. A supercritical boiler operates:
• A. Below atmospheric pressure
• B. Below the critical pressure of water
• C. Above the critical pressure of water
• D. Only with saturated steam
Rationale: Supercritical boilers operate above the critical pressure of
water, where no distinct boiling process occurs. This allows higher
efficiencies and is common in modern utility power plants.
4. Which turbine stage experiences the greatest steam volume?
• A. First stage
, • B. Admission stage
• C. Intermediate stage
• D. Final stage
Rationale: As steam expands through the turbine, its specific volume
increases significantly. Consequently, the final stages require larger
blades and greater flow areas to accommodate the expanded steam.
5. The primary advantage of regenerative feedwater heating is:
• A. Increased boiler pressure
• B. Improved thermal efficiency
• C. Lower condenser vacuum
• D. Reduced steam quality
Rationale: Regenerative feedwater heating uses extraction steam to
preheat boiler feedwater, reducing fuel consumption and improving
Rankine cycle efficiency.
6. What is the primary purpose of a deaerator?
• A. Increase steam pressure
, • B. Remove dissolved oxygen and carbon dioxide
• C. Cool condensate
• D. Separate moisture from steam
Rationale: A deaerator removes dissolved oxygen and carbon dioxide,
preventing corrosion in boilers, piping, and feedwater systems.
7. Excessive dissolved oxygen in boiler water primarily causes:
• A. Scale formation
• B. Pitting corrosion
• C. Foaming
• D. Priming
Rationale: Oxygen reacts aggressively with steel, producing localized
pitting corrosion that can rapidly weaken boiler tubes.
8. The purpose of turbine gland sealing is to:
• A. Increase turbine speed
• B. Prevent steam leakage and air infiltration
• C. Lubricate bearings
and Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. In a high-pressure water-tube boiler, the primary purpose of the
economizer is to:
• A. Increase furnace draft
• B. Cool flue gases below the dew point
• C. Preheat feedwater using waste heat from flue gases
• D. Superheat steam
Rationale: An economizer improves boiler efficiency by recovering
heat from outgoing flue gases and transferring it to incoming
feedwater. This reduces fuel consumption, minimizes thermal shock to
the boiler, and increases overall plant efficiency.
2. The critical pressure of water is approximately:
• A. 10 MPa
, • B. 16 MPa
• C. 22.1 MPa
• D. 35 MPa
Rationale: The critical pressure of water is approximately 22.1 MPa
(3,206 psi). Above this pressure, water and steam become
indistinguishable, eliminating the latent heat of vaporization.
3. A supercritical boiler operates:
• A. Below atmospheric pressure
• B. Below the critical pressure of water
• C. Above the critical pressure of water
• D. Only with saturated steam
Rationale: Supercritical boilers operate above the critical pressure of
water, where no distinct boiling process occurs. This allows higher
efficiencies and is common in modern utility power plants.
4. Which turbine stage experiences the greatest steam volume?
• A. First stage
, • B. Admission stage
• C. Intermediate stage
• D. Final stage
Rationale: As steam expands through the turbine, its specific volume
increases significantly. Consequently, the final stages require larger
blades and greater flow areas to accommodate the expanded steam.
5. The primary advantage of regenerative feedwater heating is:
• A. Increased boiler pressure
• B. Improved thermal efficiency
• C. Lower condenser vacuum
• D. Reduced steam quality
Rationale: Regenerative feedwater heating uses extraction steam to
preheat boiler feedwater, reducing fuel consumption and improving
Rankine cycle efficiency.
6. What is the primary purpose of a deaerator?
• A. Increase steam pressure
, • B. Remove dissolved oxygen and carbon dioxide
• C. Cool condensate
• D. Separate moisture from steam
Rationale: A deaerator removes dissolved oxygen and carbon dioxide,
preventing corrosion in boilers, piping, and feedwater systems.
7. Excessive dissolved oxygen in boiler water primarily causes:
• A. Scale formation
• B. Pitting corrosion
• C. Foaming
• D. Priming
Rationale: Oxygen reacts aggressively with steel, producing localized
pitting corrosion that can rapidly weaken boiler tubes.
8. The purpose of turbine gland sealing is to:
• A. Increase turbine speed
• B. Prevent steam leakage and air infiltration
• C. Lubricate bearings
