Free Heat Transfer Operations MCQs with Answers
645 Heat Transfer Operations MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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645 questions · page 4 of 33
- A. Ingots
- B. Slabs
- C. Steel coils
- D. Steel sheets
Explanation: A pusher-type reheating furnace continuously pushes steel slabs through heating zones before rolling.
Correct answer: Slabs- A. 80
- B. 130
- C. 180
- D. 250
Explanation: Sulphur in the fuel forms sulphur oxides, mainly SO₂ with some SO₃, and the resulting sulphuric-acid vapour condenses at an acid dew point…
Correct answer: 130- A. 100% H2
- B. 5% H2 + 9% N2
- C. 100% CO
- D. 95% N2 + 5% H2
Explanation: Annealing steel coils requires a reducing, non-oxidising protective atmosphere, commonly nitrogen diluted with a small amount of hydrogen.
Correct answer: 95% N2 + 5% H264. Artificial draught produced by a fan in the furnace can be controlled by the___________________?
- A. All A., B. and C.
- B. Damper
- C. Variation in the pitch of fan blades
- D. Speed of the fan
Explanation: Fan-produced draught can be adjusted by changing fan speed, throttling with a damper, or varying blade pitch in a controllable fan.
Correct answer: All A., B. and C.- A. Regenerator
- B. Ceramic recuperator
- C. Metallic recuperator
- D. None of these
Explanation: Metallic recuperators lose strength and oxidation resistance at very high temperatures, whereas ceramic recuperators can withstand…
Correct answer: Ceramic recuperator- A. Arc
- B. Resistance
- C. High frequency induction
- D. Low frequency induction
Explanation: High-frequency induction furnaces heat through induced currents concentrated near the surface because of the skin effect.
Correct answer: High frequency induction- A. 5
- B. 20
- C. 50
- D. 80
Explanation: Open-hearth furnaces have substantial heat losses through flue gases, walls, openings, and incomplete heat recovery, so their overall…
Correct answer: 20- A. By-product coke oven
- B. Calcination kiln
- C. Sintering furnace
- D. Open hearth furnace
Explanation: A by-product coke oven heats coal indirectly through hot combustion gases flowing in side flues, rather than firing the charge directly.
Correct answer: By-product coke oven- A. Reduces its thermal efficiency
- B. Is indicated by flame sting out
- C. Increases the flue gas temperature
- D. None of these
Explanation: Interpreting “air filtration” as unintended air infiltration or leakage, it introduces cold excess air into the furnace and carries heat…
Correct answer: Reduces its thermal efficiency- A. 250
- B. 650
- C. 850
- D. 1000
Explanation: SiC ceramic recuperators tolerate much higher temperatures than metallic units, but their higher cost becomes economical when combustion…
Correct answer: 650- A. By-product coke ovens
- B. Beehive coke oven
- C. Blast furnace stoves
- D. Soaking pits
Explanation: By-product coke ovens use regenerative arrangements to recover heat from hot waste gases and preheat the combustion air.
Correct answer: By-product coke ovens- A. 5
- B. 60
- C. 20
- D. 40
Explanation: Preheating combustion air to 400°C recovers a substantial part of the flue-gas sensible heat, reducing the furnace-oil requirement by…
Correct answer: 20- A. Retards the heat transfer
- B. Assists in temperature equalisation in the charge
- C. All A., B. and C.
- D. Permits the use of controlled atmosphere for the protection of stock
Explanation: A muffle separates the stock from direct flame contact, allowing a controlled protective atmosphere, more uniform temperature…
Correct answer: All A., B. and C.- A. Roasting
- B. Melting
- C. Reheating
- D. None of these
Explanation: Hearth furnaces are versatile units used for roasting, melting, and reheating operations.
Correct answer: None of these- A. Conduction
- B. Radiation
- C. Convection
- D. Either A., B. or C.; depends on the type of furnace
Explanation: At the very high temperatures found in furnaces, heat transfer by thermal radiation increases sharply with temperature and generally…
Correct answer: Radiation- A. kcal/hr
- B. kcal/m3 combustion space
- C. kcal/hr/m3 combustion space
- D. None of these
Explanation: Heat-release rate measures furnace heat intensity as the heat released per unit combustion-space volume per unit time.
Correct answer: kcal/hr/m3 combustion space- A. Are lighter
- B. Have higher pressure differential between flue gas & air side
- C. Are less costly
- D. Occupy more space
Explanation: Ceramic recuperators withstand higher temperatures but require thicker, more fragile construction and often have lower heat-transfer…
Correct answer: Occupy more space- A. Occupy more space
- B. Are less costly
- C. Are of smaller size
- D. All A., B. and C.
Explanation: A regenerator requires separate refractory storage chambers or checkerwork to absorb and release heat, so it generally occupies more space…
Correct answer: Occupy more space- A. Flame temperature
- B. Flue gas volume
- C. Fuel consumption
- D. Stack loss
Explanation: Oxygen enrichment reduces the nitrogen carried into the furnace, allowing more of the released heat to raise the combustion-gas…
Correct answer: Flame temperature- A. Glass tank furnace
- B. Cupola
- C. Open hearth furnace
- D. Reheating furnace
Explanation: A cupola is a vertical shaft furnace in which solid fuel and the charge move downward, whereas glass tank, open-hearth, and reheating…
Correct answer: Cupola