Practice Test: Question Set - 06
1. Which of the following is the most suitable for preheating combustion air above 650°C?
- (A) Regenerator
- (B) Metallic recuperator
- (C) Ceramic recuperator
- (D) None of these
2. Heat transfer takes place through a liquid medium surrounding the submerged material under heating, in case of a/an
- (A) Blast furnace
- (B) Steam boiler
- (C) Salt bath furnace
- (D) Annealing furnace
3. Artificial draught produced by a fan in the furnace can be controlled by the
- (A) Speed of the fan
- (B) Damper
- (C) Variation in the pitch of fan blades
- (D) All (a), (b) and (c)
4. Ceramic coating material for furnace refractory, which increases its emissivity and thus the radiation heat transfer rate in the furnace, comprises of
- (A) Graphite powder
- (B) Thoria
- (C) Zircon powder
- (D) Beryllium
5. Protective gas used in the annealing furnace for steel coil comprises of
- (A) 95% N2 + 5% H2
- (B) 5% H2 + 9% N2
- (C) 100% CO
- (D) 100% H2
6. Which one is not an induced draught furnace?
- (A) Blast furnace stove
- (B) Sintering furnace
- (C) High pressure boiler
- (D) None of these
7. Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C.
- (A) 80
- (B) 130
- (C) 180
- (D) 250
8. Furnace pressure is normally controlled by regulating the
- (A) Air pressure
- (B) Fuel gas pressure
- (C) Speed of I.D. fan
- (D) Damper
9. Reheating furnace (pusher type) is used for heating
- (A) Ingots
- (B) Slabs
- (C) Steel coils
- (D) Steel sheets
10. _________ is an indirectly heated furnace.
- (A) Open hearth furnace
- (B) Muffle furnace
- (C) Soaking pit
- (D) Reheating furnace
11. Shaft furnaces are used for
- (A) Smelting
- (B) Calcining
- (C) Roasting
- (D) All (a), (b) and (c)
12. Fuel economy in furnaces can be achieved by
- (A) Using oxygen enriched combustion air
- (B) Preheating the combustion air
- (C) Reducing the heat loss through furnace openings & doors
- (D) All (a), (b) and (c)
13. Regenerators are installed in
- (A) Coke ovens
- (B) Open hearth furnace
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
14. Ingress of cold air in the furnaces through cracks, charging doors, openings etc.
- (A) Reduces the flue gas temperature and makes the
furnace atmosphere oxidising
- (B) Increases the load on the induced draft fan
- (C) Reduces the furnace draught
- (D) All (a), (b) and (c)
15. Presence of SO2 in furnace gases attacks the ferrous metal by way of
- (A) Accelerating the rate of scaling
- (B) Causing metal embrittlement
- (C) Attacking the grain boundaries; particularly
severe on low carbon and nickel bearing steels at high temperature
- (D) All (a), (b) and (c)
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