Fuel and Combustion MCQs

1. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm³ ), while the C.V. is same on weight basis (i.e., kcal/kg) ?

Propane and acetylene

Propane and LPG

Sewage gas and gobar gas

B.F. gas and coke oven gas

✅ The correct answer is option A.

2. Nitrogen in coal

Is present upto 1-2%

Comes from protein in parent vegetable matter

Is recovered as ammonia during its carbonisation

All of the above

✅ The correct answer is option D.

3. Atomising steam to fuel oil ratio in a burner should be around

0.5

1.5

2.5

3.5

✅ The correct answer is option A.

4. Flue gas from the heating chamber of byproduct coke ovens is removed by

Forced draft fan

Induced draft fan

Steam ejector

Natural draft

✅ The correct answer is option D.

5. Shatter index of metallurgical coke on 2 inches and 0.5 inch screen should be respectively around __________ percent.

80 and 97

95 and 100

40 and 70

25 and 97

✅ The correct answer is option A.

6. Use of excess of combustion air in the combustion of fuels results in

Heat losses

Long flame

Condensation of water vapour from the fuel gas

None of these

✅ The correct answer is option A.

7. Prime coking coal is always blended with medium or non- coking coal before ear-bonisation

To check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls

Because, it alone produces unreactive coke

Both A & B

Neither A nor B

✅ The correct answer is option C.

8. Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of

Less air for combustion

Correct amount of air for combustion

Too much air for combustion

Pulverised coal in boilers

✅ The correct answer is option C.

9. Which of the following is a poisonous fuel gas?

Coke oven gas

Blast furnace gas

Natural gas

None of these

✅ The correct answer is option B.

10. In flue gas analysis by Orsat’s apparatus, oxygen is absorbed by

Potassium hydroxide

Cuprous chloride

Alkaline pyragllol solution

None of these

✅ The correct answer is option C.