Practice Test: Question Set - 05
1. In a furnace employing forced draught as compared to induced draught,
- (A) Air is sucked in, so air leaks are more and hence the furnace
efficiency is reduced
- (B) The fan operates hot and hence blades are liable to corrosion and
erosion
- (C) Positive pressure exists in the furnace
- (D) None of these
2. Regenerators are used for waste heat recovery in
- (A) By-product coke ovens
- (B) Beehive coke oven
- (C) Blast furnace stoves
- (D) Soaking pits
3. An example of recuperative furnace is the
- (A) Soaking pit
- (B) Open hearth furnace
- (C) Coke ovens
- (D) None of these
4. The heat recoverable from flue gases of furnaces depends on the
- (A) Thermal efficiency of furnace
- (B) Quantity of flue gases
- (C) Flue gas temperature drop through the furnace
- (D) All (a), (b) and (c)
5. Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent.
- (A) 10-15
- (B) 25-30
- (C) 45-50
- (D) 65-70
6. Operation of blast furnace stove is based on the principles of a __________ furnace.
- (A) Regenerative
- (B) Recuperative
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
7. Higher furnace temperature cannot be achieved by use of a lean fuel gas in the furnace by
- (A) Increasing the draft in the furnace
- (B) Preheating the fuel gas
- (C) Oxygen enrichment of combustion air
- (D) Preheating the combustion air
8. Air filtration in a furnace
- (A) Reduces its thermal efficiency
- (B) Is indicated by flame sting out
- (C) Increases the flue gas temperature
- (D) None of these
9. Blast furnace stoves are meant for heating
- (A) Air
- (B) Blast furnace gas
- (C) Steam
- (D) None of these
10. Which of the following is not a directly fired furnace?
- (A) By-product coke oven
- (B) Calcination kiln
- (C) Sintering furnace
- (D) Open hearth furnace
11. Heat transfer rate to the charge/stock in a furnace does not depend upon the
- (A) Type of fuels viz. solid, liquid or gaseous
- (B) Flue gas temperature
- (C) Emissivity of refractory walls
- (D) Initial temperature of the charged stock
12. Thermal efficiency of an open hearth furnace may be about __________ percent.
- (A) 5
- (B) 20
- (C) 50
- (D) 80
13. The amount of combustible escaping unconsumed from the furnace, depends upon the
- (A) Air supplied and furnace temperature
- (B) Burner design (thoroughness of mixing versus stratification)
- (C) Air preheat and the flow of gases in the furnace (mixing by
induction, by acceleration or by change of direction)
- (D) All (a), (b) and (c)
14. The electric furnace in which heat is produced by a combination of induced current and skin effect is called __________ furnace.
- (A) Arc
- (B) Resistance
- (C) Low frequency induction
- (D) High frequency induction
15. Reducing atmosphere is maintained in a
- (A) Calcination kiln
- (B) Blast furnace
- (C) Soaking pit
- (D) L.D. converter
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