Fuels and Combustion MCQs

Question 1

Pick out the wrong statement.

Accepted Answer

Cokes of high reactivity are obtained from strongly coking coals

Answer

Cokes of high reactivity are obtained from weakly coking coals

Answer

Reactivity of coke is inversely proportional to its absolute density

Answer

Abrasion index of the coke is a measure of its hardness

Question 2

The pyragallol solution used in orsat apparatus can absorb

Accepted Answer

Both O2 and CO2

Answer

Only O2

Answer

Both O2 and CO

Answer

All of the above

Question 3

Use of preheated air for combustion of fuel in the furnace, increases the

Accepted Answer

Flame temperature

Answer

Scale losses of the furnace stock

Answer

Calorific value of the fuel

Answer

None of these

Question 4

C.V. (kcal/Nm3) of gaseous fuels __________ with increase in molecular weight.

Accepted Answer

May increase or decrease, depends on combustibles

Answer

Decreases

Answer

Increases

Answer

Remains constant

Question 5

'Wobbe index' is a characteristic of

Accepted Answer

Gaseous fuels

Answer

Solid fuels

Answer

Liquid fuels

Answer

Fat coals

Question 6

Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its

Accepted Answer

All of the above

Answer

Emissivity factor is higher

Answer

Sulphur content is lower

Answer

Flue gas has lower dew point thereby facilitating more waste heat recovery

Question 7

The calorific value of natural gas is about __________ kcal/Nm3.

Accepted Answer

10000

Answer

2500

Answer

25000

Answer

35000

Question 8

Calorific value of wood gas is about __________ kcal/Nm3.

Accepted Answer

3300

Answer

1500

Answer

5400

Answer

8500

Question 9

Calorific value of coke even gas produced by low temperature carbonisation of coal is about __________ kcal/Nm3.

Accepted Answer

6500

Answer

4000

Answer

2500

Answer

10000