Fuels and Combustion

Question: Coke oven gas is a better fuel than blast furnace gas, because of its higher
[A].

calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity).

[B].

adiabatic flame temperature.

[C].

heat release rate (thus requiring smaller combustion chamber).

[D].

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

Answer: Option D

Explanation:

No answer description available for this question.

Question: A gaseous fuel in order to develop luminousity on burning, must contain
[A].

carbon monoxide

[B].

hydrocarbons

[C].

hydrogen

[D].

oxygen

Answer: Option B

Explanation:

No answer description available for this question.

Question: During combustion of gaseous fuels, deficiency of air
[A].

lengthens the flame.

[B].

tends to shorten the flame.

[C].

does not affect the flame length.

[D].

increases the flame temperature.

Answer: Option A

Explanation:

No answer description available for this question.

Question: A coal containing high amount of volatile matter will have
[A].

low ignition temperature

[B].

very little ash content

[C].

high fusion point of its ash

[D].

low adiabatic flame temperature

Answer: Option A

Explanation:

No answer description available for this question.

Question: Calorific value of dry wood may be around __________ Kcal/kg.
[A].

5

[B].

50

[C].

500

[D].

5000

Answer: Option A

Explanation:

No answer description available for this question.

Question: If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will be
[A].

low

[B].

high

[C].

very high, if the fuel is of low calorific value

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: Grindability index of a coal is 100. It implies that the
[A].

coal can be pulverised with great difficulty.

[B].

coal can’t be pulverised.

[C].

coal can be easily pulverised.

[D].

power consumption in grinding the coal will be very high.

Answer: Option C

Explanation:

No answer description available for this question.

Question: With increase in calorific value of fuels, their adiabatic flame temperatures
[A].

increase

[B].

decrease

[C].

remain unchanged

[D].

may increase or decrease ; depends on the quantity of products of combustion

Answer: Option D

Explanation:

No answer description available for this question.

Question: A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be
[A].

more

[B].

less

[C].

same

[D].

data insufficient; can’t be predicted.

Answer: Option C

Explanation:

No answer description available for this question.

Question: Adiabatic flame temperature of a fuel is dependent on the initial temperature of
[A].

fuel

[B].

air

[C].

both (a) & (b)

[D].

neither (a) nor (b)

Answer: Option C

Explanation:

No answer description available for this question.