Fuels and Combustion

Question: Efficient burning of anthracite coal requires
[A].

low preheat of air.

[B].

fine grinding.

[C].

high excess air.

[D].

all (a), (b) and (c).

Answer: Option B

Explanation:

No answer description available for this question.

Question: Low temperature oxidation of coal resulting from bad storage conditions does not decrease its
[A].

caking power

[B].

calorific value

[C].

hydrogen content

[D].

oxygen content

Answer: Option D

Explanation:

No answer description available for this question.

Question: Out of the following fuels, the difference between the net and gross calorific value is maximum in case of
[A].

pitch

[B].

fuel oil

[C].

blast furnace gas

[D].

bituminous coal

Answer: Option B

Explanation:

No answer description available for this question.

Question: Ash content in the coke produced from a coking coal having 20% ash may be around __________ percent.
[A].

6

[B].

12

[C].

18

[D].

24

Answer: Option D

Explanation:

No answer description available for this question.

Question: For every 10% increase in the excess air; the fuel consumption increases by __________ percent.
[A].

0.1

[B].

2

[C].

5

[D].

10

Answer: Option A

Explanation:

No answer description available for this question.

Question: Atomising steam to fuel oil ratio in a burner should be around
[A].

0.5

[B].

1.5

[C].

2.5

[D].

3.5

Answer: Option A

Explanation:

No answer description available for this question.

Question: Most of the coking coals are
[A].

anthracite

[B].

bituminous

[C].

lignite

[D].

none of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: Dry air requirement for burning 1 Nm3 of CO to CO2 may be around __________ Nm3.
[A].

2.4

[B].

1.75

[C].

0.87

[D].

11.4

Answer: Option A

Explanation:

No answer description available for this question.

Question: Dry air required to burn 1 kg of carbon completely may be around __________ kg.
[A].

11

[B].

2

[C].

20

[D].

38

Answer: Option A

Explanation:

No answer description available for this question.

Question: Combustion of pulverised coal as compared to that of lump coal
[A].

develops a non-luminous flame.

[B].

develops a low temperature flame.

[C].

can be done with less excess air.

[D].

provides a lower rate of heat release.

Answer: Option C

Explanation:

No answer description available for this question.