111. Protective gas used in the annealing furnace for steel coil comprises of
95% N₂ + 5% H₂
5% H₂ + 9% N₂
100% CO
100 %H₂
✅ The correct answer is option A.
Furnace Technology MCQs
112. Main gas valve in a gaseous fuel burner is a __________ valve.
Gate
Butterfly
Globe
None of these
✅ The correct answer is option A.
113. The heating capacity of continuous reheating furnace depends upon the
Hearth area and furnace temperature
Emissivity of the stock
Ratio of wall surface to stock surface
All of the above
✅ The correct answer is option D.
114. Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by
Preheating the combustion air
Oxygen enrichment of combustion air
Preheating the fuel gas
All of the above
✅ The correct answer is option D.
115. Ingress of cold air in the furnaces through cracks, charging doors, openings etc.
Reduces the flue gas temperature and makes the furnace atmosphere oxidising
Increases the load on the induced draft fan
Reduces the furnace draught
All of the above
✅ The correct answer is option D.
116. Reverberatory furnace is used for
Roasting/reduction of ores
Annealing steel coil
Heating air
Steel melting
✅ The correct answer is option A.
117. Size of the combustion chamber of a furnace depends upon the
Heat release rate of the fuel
Preheat temperature of fuel & air
Method of mixing the fuel & air
All of the above
✅ The correct answer is option D.
118. Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above __________ °C, because corrosion prevails at higher temperatures.
350
750
1050
1250
✅ The correct answer is option B.
119. Decarburisation of steel
Is the removal of carbon from iron carbide (Fe₃C)
Affects its crystalline structure
Is favoured by CO₂
All of the above
✅ The correct answer is option D.
120. An example of indirectly heated furnace is the
Soaking pit
Muffle furnace
Reheating furnace
None of these
✅ The correct answer is option B.