Furnace Technology

Question: Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400°C results in saving of about __________ percent furnace oil as compared to its combustion with atmospheric air, if the flue gas outlet temperature from the soaking pit is 1200°C.
[A].

5

[B].

60

[C].

20

[D].

40

Answer: Option C

Explanation:

No answer description available for this question.

Question: Flue gas outlet temperature from the chimney of any furnace should be ideally about __________ °C.
[A].

50

[B].

100

[C].

150

[D].

250

Answer: Option C

Explanation:

No answer description available for this question.

Question: Large tonnage of refractory bricks are dried in a
[A].

shaft furnace

[B].

rotary hearth furnace

[C].

tunnel kiln

[D].

muffle furnace

Answer: Option C

Explanation:

No answer description available for this question.

Question: Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C.
[A].

250

[B].

650

[C].

850

[D].

1000

Answer: Option B

Explanation:

No answer description available for this question.

Question: Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above __________ °C, because corrosion prevails at higher temperatures.
[A].

350

[B].

750

[C].

1050

[D].

1250

Answer: Option B

Explanation:

No answer description available for this question.

Question: 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.

Answer: Option A

Explanation:

No answer description available for this question.

Question: 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.

Answer: Option C

Explanation:

No answer description available for this question.

Question: 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

Answer: Option B

Explanation:

No answer description available for this question.

Question: __________ is an indirectly heated furnace.
[A].

Open hearth furnace

[B].

Muffle furnace

[C].

Soaking pit

[D].

Reheating furnace

Answer: Option B

Explanation:

No answer description available for this question.

Question: An improved and fuel efficient version of the pusher type reheating furnace is the __________ furnace.
[A].

walking beam

[B].

shaft

[C].

tunnel

[D].

rotary hearth

Answer: Option A

Explanation:

No answer description available for this question.