Practice Test: Question Set - 07
1. Which is the most thermally efficient furnace?
- (A) Reheating furnace
- (B) Reverberatory furnace
- (C) Rotary kilns
- (D) Boiler furnace
2. In a heating process, a heat flow diagram in which the quantities of heat in the various items of a heat balance are represented by the width of a band is called the
- (A) Ostwald chart
- (B) Cox chart
- (C) Sankey diagram
- (D) None of these
3. The advantages of firing pulverised coal in the furnace lies in the fact that, it
- (A) Permits the use of high ash content coal
- (B) Permits the use of low fusion point ash coal
- (C) Accelerates the burning rate and economises on fuel consumption
- (D) All (a), (b) and (c)
4. In producer gas making furnace, steam is added along with air to mainly control the
- (A) Fusion of coal ash & clinker formation
- (B) C. V. of producer gas
- (C) Temperature of producer gas
- (D) Tar content in producer gas
5. ________ furnace is not an electric furnace.
- (A) Arc
- (B) Induction
- (C) Pot
- (D) Resistance
6. Pick out the wrong statement.
- (A) Addition of methane to the furnace atmosphere
reduces decarburising by hydrogen
- (B) Nitrogen in presence of steam decor-burises
high carbon steel, whereas hydrocarbon gases carburise the surface of steel at
annealing temperatures
- (C) Active nitrogen (formed by cracking ammonia at
the metal surface) cause nitride formation with increase in surface hardness
- (D) None of these
7. To reduce the stack loss, heat recovery from flue gas can be done by
- (A) Preheating of cold stock
- (B) Preheating of combustion air
- (C) Steam generation in waste heat boilers
- (D) All (a), (b) and (c)
8. Thermal efficiency of furnaces can be improved by
- (A) Waste heat recovery from flue gas
- (B) Minimising heat losses from furnace walls
- (C) Maintaining proper draught
- (D) All (a), (b) and (c)
9. Size of the combustion chamber of a furnace depends upon the
- (A) Heat release rate of the fuel
- (B) Preheat temperature of fuel & air
- (C) Method of mixing the fuel & air
- (D) All (a), (b) and (c)
10. Power required in case of forced draught as compared to induced draught (for the same draught produced) is
- (A) Same
- (B) Less
- (C) More
- (D) Either more or less; depends on the flue gas density
11. An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called __________ furnace.
- (A) Resistance
- (B) Arc
- (C) Low frequency induction
- (D) None of these
12. While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about ________ °C.
- (A) 2000
- (B) 3000
- (C) 4500
- (D) 6000
13. Which of the following is a heat treatment furnace?
- (A) Muffle furnace
- (B) Annealing furnace
- (C) Reheating furnace
- (D) Rotary kiln
14. Rotary kilns are used in the
- (A) Calcination of limestone & dolomite
- (B) Cement manufacture
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
15. In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of
- (A) Use of non-preheated combustion air
- (B) Use of pulverised solid fuels
- (C) Imperfect mixing of fuel & air and
infiltration of air
- (D) Use of excessive positive draft in the furnace
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