Practice Test: Question Set - 10
1. The thermal efficiency of a steel slab reheating furnace (walking beam type) may be about _________ percent.
- (A) 15
- (B) 40
- (C) 70
- (D) 85
2. Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of
- (A) Furnace oil with air
- (B) Furnace
oil with oxygen
- (C) Blast furnace gas
with air
- (D) Blast
furnace gas with oxygen
3. Neutral atmosphere is maintained in a/an __________ furnace.
- (A) Cold
rolled steel coil annealing
- (B) Open hearth
- (C) Soaking pit
- (D) Walking beam
reheating
4. Which of the following is not an additive for flue gases from furnace to reduce its dew-point?
- (A) Ammonia
- (B) Fine
dolomite
- (C) Alkaline
powders
- (D) None
of these
5. An example of indirectly heated furnace is the
- (A) Soaking pit
- (B) Muffle
furnace
- (C) Reheating
furnace
- (D) None of these
6. The function of an economiser in a boiler is to preheat the
- (A) Feedwater
- (B) Combustion air
- (C) Pulverised coal
- (D) Furnace oil
7. Thickness of stock does not affect the fuel economy of furnaces, if the material to be heated is of
- (A) Low
emissivity
- (B) High
thermal conductivity
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
8. Which of the following furnaces will have maximum thermal efficiency?
- (A) Soaking pits
- (B) Walking beam
reheating furnace
- (C) Boiler furnace
- (D) Rotary kilns
9. The resistance furnace produces heat by the
- (A) Electric
arc struck between electrodes and the charge
- (B) Flow of current
through a heating element
- (C) Combination of
induced current and skin effect
- (D) None of these
10. Ostwald charts are meant for
- (A) Computing
the excess/deficiency of combustion air
- (B) Calculation
of flue gas temperature
- (C) Computation
of flue gas analysis
- (D) None of these
11. Dampers are located
- (A) Before the I.D fan
- (B) After the I.D. fan
- (C) Near the top of the
chimney
- (D) Anywhere after the
I.D. fan
12. Regenerators as compared to recuperators for the same duty
- (A) Store smaller
quantity of waste heat
- (B) Are lighter &
compact
- (C) Involve higher
initial cost
- (D) All (a), (b) &
(c)
13. Calcination of limestone to produce lime is done in a ________ kiln.
- (A) Tunnel
- (B) Rotary
- (C) Vertical shaft
- (D) Both (b) and (c)
14. Which furnace employs natural draft?
- (A) Coke oven
- (B) Boiler
- (C) Rotary kilns
- (D) L.D.
converter
15. Oxygen enrichment of combustion air does not result in increase of the
- (A) Flame
temperature
- (B) Oxygen in the flue
gas
- (C) Stack loss
- (D) Heat transfer rate in
the furnace
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